International Workshop on Groundnutsagropedia.iitk.ac.in/sites/default/files/RA 00023.pdf · 2016-05-28 · Groundnut Foliar Diseases in the United States D. H. Smith 186 Research

Proceedings

International Workshopon Groundnuts

International Crops Research Institute for the Semi-Arid Tropics

Proceedings of the

International Workshop

on Groundnuts

ICRISAT CenterPatancheru, India

1 3 - 1 7 October 1980

International Crops Research Institute for the Semi-Arid TropicsICRISAT Patancheru P.O.

Andhra Pradesh 502 324, India

Correct c i ta t ion: ICRISAT (Internat ional Crops Research Inst i tute for theSemi-Ar id Tropics). 1980. Proceedings of the International Workshop onGroundnuts , 13-17 October, 1980, Patancheru, A.P., India.

Workshop Coordinator

and

Scientific Editor

R. W. Gibbons

Publication Editor

J. V. Mertin

The International Crops Research Institute for the Semi-Arid Tropics (ICRISAT)is a nonprofit scientific educational institute receiving support from a variety ofdonors. Responsibility for the information in this publication rests withICRISAT or the individual authors. Where trade names are used this does notconstitute endorsement of or discrimination against any product by theInstitute.

Contents

F o r e w o r d vi i

O p e n i n g S e s s i o n 1

Welcome and Overview of ICRISAT L. D. Swindale 3Research at ICRISAT — An Overview J. S. Kanwar 6ICRISAT's International Cooperative Program J. C. Davies 8The ICRISAT Groundnut Program R. W. Gibbons 12

Sess ion 2 — Research O r g a n i z a t i o n a n d D e v e l o p m e n t 17

Indian Coordinated Research Project on Vikram Singh 19Oilseeds wi th Special Referenceto Groundnut

The Role and Function of the IHRO in P. Gillier 25Groundnut Research and Development

Peanut Collaborative Research Support C. R. Jackson and 31Program Planning D. G. Cummins

Research and Extension Inputs Resulting Ray O. Hammons 33in High Yields of Groundnuts in the USA

Summary of Discussion — Session 2 40

Sess ion 3 — Gene t i cs a n d B r e e d i n g 45

Groundnut Genetic Resources at ICRISAT V. R. Rao 47

Breeding Methodology for Groundnuts A. J. Norden 58

Groundnut Breeding at ICRISAT S. N. Nigam, S. L. Dwivedi, 62and R. W. Gibbons


Sess ion 4 — Cy togene t i cs a n d Ut i l i za t ion of W i l d Spec ies 71

Cytogenetic Investigations in the Genus H. T. Stalker 73Arachis

Utilization of Wi ld Arachis Species at A. K. Singh, D. C. Sastri, 82ICRISAT and J. P. Moss


Sess ion 5 — C r o p Nu t r i t i on a n d A g r o n o m y 93

Increasing Nitrogen Fixation of the J. C. Wynne, G. H. Elkan, 95

Groundnut by Strain and Host Selection and T. J. Schneeweis

Studies on Nitrogen Fixation by Groundnut P. T. C. Nambiar and 110at ICRISAT P. J. Dart

Physiological Basis for Increased Yield D. E. McCloud, W. G. Duncan, 125Potential in Peanuts R. L. McGraw, P. K. Sibale,

K. T. Ingram, J. Dreyer,and I. S. Campbell

Groundnut in Intercropping Systems M. S. Reddy, C. N. Floyd,and R. W. Willey

133


S e s s i o n 6 — G r o u n d n u t E n t o m o l o g y 147

Resistance of Groundnuts to Insects W. V. Campbell and 149

and Mites J. C. WynneGroundnut Pest Research at ICRISAT P. W. Amin and

A. B. Mohammad158


Sess ion 7 — G r o u n d n u t Pa tho logy 169

Cylindrocladium Black Rot (CBR) Disease Marvin K. Beute 171of Peanut

Sclerotinia Blight of Groundnut — a D. Morris Porter 177Disease of Major Importance in the USA

Groundnut Foliar Diseases in the United States D. H. Smith 186Research on Fungal Diseases of Groundnut P. Subrahmanyam, 193

at ICRISAT V. K. Mehan,D. J. Nevi l l , andD. McDonald

Studies of Resistance to Foliar Pathogens D. J. Nevill 199International Aspects of Groundnut Virus D. V. R. Reddy 203

ResearchGroundnut Virus Research at ICRISAT A. M. Ghanekar 211Summary of Discussion — Session 7 217

S e s s i o n 8 — C o u n t r y R e p o r t s 221

Asia and Austral iaAustral ia K. J. Middleton 223Bangladesh M. A. Hamid 226Burma U. Win Naing 230Malaysia Halim B. Hamat and

Ramli B. Mohd. Noor233

Thai land Arwooth Na Lampang,Terd Charoenwatanaand Dumrong Tiyawalee

237

South AmericaArgent ina Jose R. Pietrarelli 241

Brazil A. S. Pompeu 244Venezuela Bruno Mazzani 247

iv

v

AfricaMalawi P. K. Sibale and C. T. Kisyombe 249Mali D. Soumano 254Mozambique A. D. Mal i thano 257Niger A. Mounkaila 262Nigeria S. M. Misari , C. Harkness,

and A. M. Fowler264

Senegal J. Gautreau and O. De Pins 274Sudan H. M. Ishag, M. A. Ali,

and A. B. Ahmadi282

Tanzania A. Bolton 285Z imbabwe G. L. Hi ldebrand 290


S e s s i o n 9 — P l e n a r y S e s s i o n 301

Chairmen Summaries 303General Discussion 308

A p p e n d i x 1 — Pos te r S e s s i o n P a p e r s 313

A p p e n d i x II — Par t i c i pan ts 319

F o r e w o r d

One of the important functions of an international research institute is theholding of workshops, conferences, and symposia where delegates f rommany parts of the wor ld can meet together to discuss research problems andprogress. ICRISAT has hosted many such workshops, but this is the first onethat has been held solely for groundnuts.

It was an appropriate t ime to hold such a meeting, as our program atICRISAT Center is almost fu l ly staffed and we are preparing to place staff atresearch stations in Africa.

The research program of ICRISAT presented at the Groundnut Workshopand the deliberations and discussions thereon clearly indicate that theInstitute's main lines of research, aimed at overcoming major yield-reducingconstraints, are appropriate and welcome.

One area that undoubtedly needs early and more concentrated attention isdrought resistance. It is alarming to hear of the devastation that has affectedgroundnut production and reduced the cultivated area, particularly in the drierzones of West Africa.

We are pleased that the groundnut physiology program is now under way,and we look forward to frui t ful cooperation wi th our colleagues in nationalprograms.

It is also pleasing to f ind that the Indian groundnut research program isbeing strengthened and that a new national center is being formed in the highproduct ion area of Gujarat State. This is very appropriate because of the largedeficit of vegetable oils in India, wh ich in turn means that precious foreignexchange has to be spent on imports despite India being the largest groundnutproducer in the wor ld .

There is undoubtedly also a pressing need in many other parts of the wor ldto increase groundnut product ion and initiate more research. We believe thatICRISAT can help.

On behalf of ICRISAT I wou ld like to thank all the delegates, many of w h o mtravelled far to Hyderabad, for making this workshop a success.

L D. SwindaleDirector General

vii

Opening Session

Chairman: R. W. Gibbons

W e l c o m e and O v e r v i e w o f ICRISAT

L. D. Swinda le*

It is w i th very considerable pleasure that I we lcome you to ICRISAT and to our first Interna-t ional Workshop on Groundnuts. This morn ing I want to g ive you an overview of ICRISAT and itsactivities. I wi l l not deal very much w i thgroundnuts because you are going to discussthis subject in depth over the next f ew days.

ICRISAT is the International Crops ResearchInstitute for the Semi-Arid Tropics. Our logoshows that we work on cereals, and on legumes,and because we are work ing in the semi-ar idtropics, our logo also reminds us of the impor-tance of every drop of water, the scarcestnatural resource in the region.

There are four objectives in the mandatestatement of ICRISAT — (1) to serve as a wor ldcenter for the improvement of the genetic po-tential fo r grain yield and quali ty of groundnuts,sorghum, pearl mil let, pigeonpea, and chickpea;(2) t odeve lop fa rm ingsys tems to help increaseand stabilize agricultural product ion throughmore effective use of natural and human re-sources in the semi-arid t ropics; (3) to identifysocioeconomic and other constraints to agricul-tural development in the semi-arid tropics, andto evaluate alternative means of al leviatingthem th rough technical and inst i tut ionalchanges; and (4), to do what we are do ingtoday — assisting national and regional re-search programs through cooperat ion and bysponsor ing conferences, operat ing interna-t ional t ra in ing programs, and assisting exten-sion activities. These are the four objectives ofthe mandate statement of ICRISAT.

We generally define the semi-arid tropics(SAT) in terms of the distr ibut ion of rainfalland the potential evapotranspirat ion (PET)throughout the year. The rainfall tends to occurmost ly in a few months of the year whi le theevapotranspirat ion exceeds rainfall fo r most ofthe year. But for a short per iod, long enough forcropping, the reverse is t rue, and rainfall ex-

* Director General, ICRISAT.

ceeds PET giving us normally enough water togrow crops, and a little extra. One of the thingsthat we are doing in ICRISAT is trying to deter-mine if we can make good use of that little extra.The semi-arid tropics cover a very large area ofthe world including a large part of the Africancontinent, most of the South Asian subconti-nent, appreciable and significant areas in theAmericas, other parts of Asia, and Australasia.

Much of the world production of the fiveICRISAT crops is consumed as human food inthe SAT. The crops are low in cash value andwith one exception (groundnuts), do not enterworld trade to any extent. There has been verylittle research in the developed countries onmost of these crops, mainly because they aretropical and subtropical crops, and inadequateresearch in the developing countries. Fertilizer-responsive genes are yet to be discovered,particularly for the legumes. The crops aregrown mostly under rainfed conditions, theyields are low and unstable, and high inputtechnology has not yet been feasible. Veryimportant to us is the fact that they are grown bysubsistence farmers in the poorest countries ofthe world.

We are not discouraged by all these thingsbecause we believe that the potential for pro-duction is very high. Here at ICRISAT, underrainfed conditions, we have already obtainedseveral times the average yields of these cropsunder low-input conditions, and as you know,much higher yields again are possible in moreintensive agriculture. We believe the potential isthere — we know the potential is there. It is ourjob to unlock the potential and bring it to the useof the small farmers. They have limited meansand limited inputs and are without the benefitsof regular regional irrigation. They constitute a particular target group for which ICRISAT hasbeen charged to work by the ConsultativeGroup on International Agricultural Research,which is the donor group behind us. It is ourresponsibility to concentrate our efforts for thebenefits of this target group, but naturally we

3

also work for the other producers of our crops.This is particularly t rue of the crop that interestsyou — groundnuts. The small farmer of l i-mi ted means is a c o m m o n sight here in India,and also in the Afr ican countries, CentralAmerica, and the other countries covered by theICRISAT mandate.

A l though the small farmer is our target group,we also have a client group, which consists ofthe scientists, and workers in the national re-search institutions, extension, and action agen-cies. We are an international institute, and it isnot our responsibi l i ty to undertake the work ofnational programs of scientific research or ex-tension. We work for and help our cl ient groupwi th our results so that they in tu rn , wi l l help thesmall farmer. We fashion our products so thatthey wi l l help scientists help the small farmer.That is the way in which we work.

At ICRISAT Center, our crop improvementwork is conducted on t w o major soil types of theSAT. One is the black deep Vertisol (the blackcotton soils), and the other is the red soil wi th a sandy top and a clay subsoi l . This latter type weknow as Alfisol. In Africa, however, we tend towork much more upon very sandy soils like thesoils on the outskirts of Niamey in Niger wherethere is a litt le concentrat ion of clay in the lowerparts of the horizon but, for the most part, thesoil is very sandy, and has a very low exchangecapacity and very l ow nutrient status.

Regarding our programs in West Africa, wehave scientists work ing together wi th nationalprograms in Senegal, Mal i , Upper Volta, Niger,Nigeria, and also in Sudan, and in East Africa.Our major effort at the present t ime is inOuagadougou in Upper Volta, and we are alsot ry ing to establish a center at Niamey in Niger.At the present t ime, we do not have a programwork ing on groundnuts in Africa but our donorgroup, the CGIAR, has agreed that we should.In the near future, this year and next year,we hope to establish an ICRISAT groundnutprogram in Afr ica, possibly in t w o differentlocations or localit ies, w i th the first one prob-ably being in Malawi .

In carry ing out our mandate for the smallfarmer and our cl ient scientists, we concentratefirst ly upon collecting germplasm f rom all overthe wor ld . We have many lines now. This hasbeen done w i th the considerable help of theIndian Government quarant ine services andpart icularly the Central Plant Protection Train-

ing Institute (CPPTI) which has undertaken theresponsibi l i ty of quarantine services for mate-rial coming into India fo r ICRISAT and its releaseto us. We are interested in the highly responsiveand stable high yielding varieties. We test forstability in an international network at Hissarin northern India, at ICRISAT Center, atBhavanisagar in southern India, at Kamboinsein Upper Volta, and in the other countr ies that I have ment ioned in West Africa.

We carry out research on diseases of our f ivecrops and we also work upon insects includingthe pod borer, wh ich is probably the worstinsect pest in the tropical wor ld . We also workupon weeds, including resistance to parasiticweeds such as Striga wh ich occurs in the cerealcrops both in India and Africa. This is a veryserious pest of the cereal crops and there aresimilar parasitic pests upon groundnut andother legumes.

In addi t ion to our work on crop improvement ,we have a farming systems program and a pro-gram in socioeconomics. Try ing to overcomethe constraints that small farmers face is verydiff icult and you cannot do i t i f you do not knowwhat they are. So we are undertaking a consid-erable program, probably the largest programin social sciences in any of the internationalagricultural research centers, in order to under-stand, quanti tat ively if possible, the exactreasons for the lack of development amongstthis group of people in the SAT. For example,we are t ry ing to understand at f irst hand whyareas of Vertisols, the deep black soils, arebeing left fa l low when there is plenty of water inthe rainy season. What are the reasons thatcause the farmers to do this and are theysolvable by scientific research?

We have done a great deal of work in thisparticular f ield and recently we released a document summar iz ing our results to date onfarming systems components for selectedareas in India. This evidence was gained overabout 8 years of work here and in conjunct ionwi th the Al l India Coordinated Research Pro-jects. We can now say how to overcome manyof the constraints to development in theseareas, particularly in the areas w i th deep blacksoils and where the monsoon rainfall is reliable.Under these condi t ions we think we now havethe elements, indeed most of the components,of a new farming systems technology. We arenow discussing w i th the Indian national pro-

4

gram the way in wh ich this can be tested on a larger scale than w e , as an international insti-tute, are able to handle. Our new technology isbased upon a watershed concept in wh ich wetry to deal w i t h the who le watershed as a unit . I tincorporates improvements in cropping sys-tems, in land and water management, in im-p lements , in inst i tu t ions, and in h u m a n ac-tivit ies. Al l these changes are necessary in orderto implement the improved technology. Fortu-nately, a l though the package is complex it ispossible to implement it step by step. We have a good idea of wha t are the lead practices that canbe relied upon to start the farmers in thisprocess of development and then a l low them topick up other practices at later stages. Dr.Kanwar wi l l probably discuss th is w i th you inhis paper.

I have noticed that the Groundnuts Workshopprogram does not include the t ra in ing aspectsof ICRISAT or the possibi l i t ies for t raining hereat ICRISAT Center, so I thought I wou ld ment ionthis myself. There are people here, particularlyf rom the developing countries, w h o might w ishto see that their younger colleagues have op-portunit ies for t ra in ing here. There are alsopeople f rom developed countr ies w h o mightlike to know that we have t ra in ing programs forgraduate students and postdoctoral candi-dates.

ICRISAT Center provides f ive major types oft ra in ing — international internships, researchfel lowships, research scholarships, in-servicetraining programs, and apprenticeships.

The international internships are for post-doctoral fe l lows f r om our donor countr ies togive them an oppor tun i ty to work for a wh i le atICRISAT in a developing country. Researchfel lows are M.Sc. and Ph.D. degree holdersf rom SAT countr ies w h o work w i th ICRISATscientists on specific problems for one or moreyears. We also have research scholars w h o arestudents of overseas universit ies and of univer-

sities here in India. These scholars undertakecertain aspects of their research program hereat ICRISAT under the guidance of an ICRISATscientist w i th the cooperat ion of their thesis ordissertation supervisor f r om their own univer-sity.

Our largest training program is the in-serviceprogram. We br ing in young scientists andextension workers for a very concentratedprogram of training, usually for one croppingseason, on all aspects of how to g row a particu-lar crop and h o w t o conduct good f ield researchwi th it. Our training phi losophy is problem-areaand ski l l -development centered; practical ex-perience out in the f ield is the heart of ourt ra in ing program. We try to teach our traineesthe importance of socioeconomic relationshipsassociated wi th new technology. We insist thatthey undertake individual experiments and de-monstrat ions and learn something about man-agerial, communicat ion, and leadership skills.We have training programs in crop improve-ment, crop product ion, and in farming systems.We teach people to learn by gett ing them to dothings for themselves, such as gett ing behind a cou pie of bullocks for thef i rs t t ime in their l i fe orplanning their o w n experiments, organizingthem, laying them out in the f ie ld , and thenl iv ing w i th the results even if the results are notsuccessful.

The students learn f r om both their successesand failures. When they receive their certif icatehere at the complet ion of their training program,they can go back h o m e w i th t he f eeling that theyhave learned something. They wi l l have theconfidence to go out in the f ield and work eitherin research or extension and not f ind that theyhave only a great deal of academic knowledgewi th very litt le practical skill in the growing ofcrops.

Thank you very much. You are indeed we l -come here and I hope that you have an enjoy-able and prof i table conference.

5

Research at ICRISAT — An Overview

J. S. Kanwar*

I t is my great pleasure indeed to welcome you tothe ICRISAT Center and to participate in thisworkshop.

Dr. Swindale in his address has given you thespectrum of all the activit ies of ICRISAT — itsgoals, mandate, problems, approaches, targets,achievements and h o w we funct ion. Becauseour statist ician tel ls us that replication is essen-t ial in scientif ic agricul ture, I am going toreplicate Dr. Swindale's address just toimprove the reliabil i ty of the results and makethem better interpreted and better understood.

I wilt g ive you a brief idea about the activitiesof our f i f teen programs. Six of them are calledresearch p rograms, seven are the researchsupport programs and the other two , that isInformat ion and Adminis t rat ion, are our sup-port programs.

ICRISAT has to work for t w o groups of people.There is the target group consist ing of resourcepoor farmers. The other group, the so calledclient g roup, is composed of scientists, exten-sion workers and technicians.

In the semi-ar id t rop ics, SAT, the farmertarget g roup has to produce under very diff icultcl imatic condit ions. There is a short rainy sea-son fo l lowed by a long dry per iod. The rainfallreceived is also very variable and no two yearsare the same. Somet imes the rainfall is veryl ight and somet imes it is so heavy that the far-mers experience f looding and drainage prob-lems.

In the SAT, there are Alf isol and Vertisol soiltypes. The former are red soils, low in fert i l i tyand moisture-hold ing capacity, and they areused for the cult ivat ion of groundnuts and othercrops. The Vertisols are black soils w i th a highmoisture-holding capacity, but with low fertilityThey are very dif f icult to manage particularlydur ing the kharif season, i.e., the monsoon orrainy season, when they should be cropped butmany of them are left fa l low.

* Director of Research, ICRISAT.

Regarding our strategies for research, thefirst emphasis is on assembl ing, evaluating anduti l izing the germplasm resources. This is fo l -lowed by str iving to bui ld higher yield potent ialand yield stabil i ty in the hybr ids, compositesand exper imenta l variet ies. We are also in-terested in incorporat ing disease and pest resis-tance, and better nutr i t ional qualit ies into ourmandate crops.

Not only do we at tempt to improve grain ac-ceptabil ity but we also try to improve the lysinecontent of sorghum and mil let grains, and thesulphur-bearing amino acid content of thepulse seeds.

We are developing a computer ized system ofrecords for our 50 000 germplasm lines wh ichhave been accumulated over the last 6 - 7 years.Not only do we receive germplasm f rom manycountries, but we also distr ibute thousands ofsamples to a great many national programs inthe wor ld .

The f ield experiments of ICRISAT scientistshave shown that all of the mandate crops havegood po ten t i a l f o r increased y ie lds underrainfed condit ions as indicated in the fo l lowingtable:

Experimental y ie ld at

Average

ICRISAT (kg/ha)

Average High fert i l i ty Low fert i l i ty

SAT y ie ld and g o o d and averageCrop (kg/ha) management management

Sorghum 842 4900 2627Pearl Mil let 509 3482 1636Chickpea 745 3000 1400Pigeonpea 600 2000 1000Groundnut 794 2573 1712

The problem is that unless the farmers areable to get those types of yields, wecanno t get a big improvement in national product ion.

Regarding disease research at ICRISAT, we

6

disseminate resistant material developed hereto the national programs for screening in theircountr ies, part icularly at the hot spots in thein te rna t iona l nu rsery sys tem. Diseases onwhich ICRISAT is work ing include downy mi l -dew on sorghum and pearl mi l let ; ergot onpearl mi l le t ; grain molds and charcoal rot ofso rghum; steril i ty mosaic in p igeonpea; w i l t ofchickpea; and leaf spots and rust of groundnut .

In entomology, we have evolved a screeningtechnique for shoot fly and we are also develop-ing one to screen for pod borers.

Using a technique developed by ICRISAT, wecan screen plants fo r d rough t to lerance, inwh ich d i f ferent mo is tu re level reg imes areapplied to the plants being tested.

ICRISAT scient is ts are a lso s tudy ing theparasitic weed Striga. Apart f r om being a seri-ous problem in Afr ica, i t is now causing consid-erable concern in India too and it is be ingscreened here.

Recognizing that the ul t imate reality of what -ever improved material we produce is its suita-bil i ty and acceptance, we test newly developedmaterial w i th a tasting panel. What is suitablefor India may not be suitable for Afr ica and whatis suitable for the Sudan may not be suitable forNigeria and so on.

Our Economics P rog ram has t w o ma jo rsubp rog rams — p roduc t i on economics andmarke t ing economics . They are exam in ingmarketing problems and how to improve thepossibi l i t ies of farmers making more profits.

We are concerned wi th the poor fert i l i ty ofsoils, and the drainage problems associatedwi th the black soils, i.e., the Vertisols. Phos-phate, zinc and sulphur deficiences have beennoted.

ICRISAT has developed a watershed con-cept in its Farming Systems program so thatwater movement f r om the higher levels is con-

served by var ious techniques instead of all m o v -ing to the lower levels. I wou ld like to emphasizethe point that the availabil i ty of water acts as a catalyst for a new agriculture. When farmersf ind that they have some water available, theyare prepared to take risks.

In the farming system developed here, broadbeds and fu r rows are used and appropr iatemachinery is necessary to make them. Also, a suitable cropping system must be incorporatedinto the overall product ion scheme.

Materials are tested here at ICRISAT under a range of env i ronmenta l s i tua t ions such asunder pesticide protect ion; w i thout pesticideprotect ion; irr igated and nonirr igated cond i -t ions; and in low and high ferti l i ty areas.

Wi th new developments, we are very con-scious of the fac t tha t unless a farmer sees a twoor three-fold benefit, he wi l l not be very en-thusiastic about adopt ing a new technique ornew variety. In particular, under dryland farmingcondit ions, a farmer is not prepared to take toomany risks because of cl imatic condit ions. Sonatural ly, we must f ind a technology wh ichgives him good stability in product ion andalso more benefits.

In order to get new developments in technol-ogy and new varieties to farmers, we are in-volved in a linkage system for the transfer oftechnology. We have cooperative linkages w i thvarious international institutes, w i th nationalinstitutes, and w i th var ious other organizations.

Fundamental ly, the ICRISAT program actsthrough t w o bases — the seed base and the re-source base. ICRISAT reaches the nat ionalprograms and they in turn work wi th the far-mers. When a farmer adopts a new variety andcan say at harvest t ime that he has just ob-tained the largest yield in all his farming life, thenwe know that we have achieved one of ourobjectives — increased agricultural product ion.

7

ICRISAT's International Cooperative Program

J. C. Davies*

The basic objectives of ICRISAT and the thrustsof the research effort have been explained bymy col leagues, Drs. Swindale and Kanwar. I donot propose to reiterate these, but I wou ld like tore-emphasize that an impor tant premise, whenthe Insti tute was established, was that i t wou ldserve to strengthen and suppor t established ag-ricultural research programs and effort, both inthe host country and other nations in the SAT.Clearly, the estab l ishment of a Cooperat iveProgram was vi tal in achieving this goal. About50 countr ies on four cont inents have some SATareas w i th in their boundaries (20 mi l l ion sqmiles), and the major i ty of these are less de-veloped or are developing countries. There wasa necessity to de te rmine pr ior i ty countr ies,crops, and research areas for maximizing thereturns f rom resource input — both by way ofstaff and fund ing in cooperative ventures.

V i t a l S t a t i s t i c sI n f l u e n c i n g L o c a t i o n o ft h e C o o p e r a t i v e P r o g r a m

Some 66% of the SAT area is in Afr ica — 24% inW. Afr ica, 2 2 % in E. Africa, and 20% in southernAfrica. The populat ion of the SAT is around 600mi l l ion — 56% of wh ich , i.e., about 350 mi l l ion ,l ive in India (which occupies only 10% of theSAT land surface). About 90 mi l l ion live in SATW. Africa. The second largest SAT country is inAfr ica, the Sudan, which has only a minute 3%of the SAT populat ion in 8% of the land area.These f igures h ighl ight the w ide differences inland to populat ion ratios wh ich exist in the SATcountries.

Populat ions in Afr ica are g row ing at an ex-t remely high rate. A further factor which af-fected program si t ing was that in the 1970's, a drought si tuat ion existed in much of Afr ica, butparticularly in sub-Sahalian Afr ica, causing un-to ld suffer ing and misery to mi l l ions of people.

* Director fo r Internat ional Cooperat ion, ICRISAT.

A study of the statistics for three of ICRISAT'smanda te c rops — mi l l e t , s o r g h u m , andg roundnu ts— indicate their importance in theSAT, both in hectarage and product ion te rms(Table 1). However, average yields are low.Cereals are very important in the SAT and t w oof ICRISAT's mandate crops, mi l let and sor-ghum, are vitally important, especially in v iew oftheir comparat ive drought tolerance. Mil let isimportant in almost all the West Afr ican coun-tries and India, and sorghum in several coun-tr ies (Table 2). In Eastern Afr ica, mil let is of greatimportance in Sudan and Tanzania. Sorghum isof pr ime importance in the Sudan and of con-siderable and possibly increasing importance inTanzania, and to an extent in the other countr ies(Table 3).

These facts together w i th the predict ions of a number of agencies that food deficits wi l l be a f e a t u r e o f t h e 1980's in A f r i c a , g rea t l yinfluenced the development, crop choice andsit ing of our init ial cooperative research effortsin the West Afr ican region.

P r o g r a m D e v e l o p m e n ta n d S t r u c t u r e i n W e s t A f r i c aa n d Eas t A f r i c a

In early 1975, UNDP and ICRISAT entered into a 3-year contract that had as its pr ime objectivestrengthening of exist ing West Afr ican pro-grams and development of higher y ie ld ing andstress resistant sorghums and mil lets. The pro-ject covered 12 countr ies in W. Afr ica stretchingf rom Senegal to Nigeria; subsequently Sudanwas included. The strategy in the f i rst phasewas to post ICRISAT scientists to exist ing re-search s tat ions at Bambey, Senega l ; Kam-boinse (init ial ly Farako Ba), Upper Vol ta ; Maradiin Niger; Samaru in Nigeria; and Wad Medani inthe Sudan — thus ensuring close day to dayand effective col laborat ion w i t h national pro-gram scientists. The ICRISAT scientists posted

8

overseas w o u l d also effect ively col laboratew i th the ICRISAT Center at Hyderabad.

The f irst scientist was posted in 1976 and the1977 season was the first fu l l crop year. Thepattern of staf f ing in the second phase currentlyincludes — a project manager based at Dakar(partly funded by IRAT); a mil let breeder andcereal entomologis t at Bam bey, Senegal; a sor-ghum breeder (init ial ly UNDP, n o w on core); a mi l let breeder, a cereal pathologist and ag-ronomist at Kamboinse. The Dutch Govern-ment assisted w i th an agricultural engineer.Elsewhere we have a mil let breeder at Maradi , a

mil let breeder and cereal pathologist at Sam-aru, and mi l let and sorghum breeders at WadMedani.

To this network there have been added in thepast few years an agronomist and a sorghum/mil let breeder in Mali under a USAID contract,and under a subcontract to IITA/USAID, a sor-ghum breeder in Tanzania. In the sorghum andmil let crops therefore, a strong interconnectingseries of teams has been fo rmed. This w idespread of teams, to a considerable extent, cov-ers the range of ag roc l ima to log ica l , b roadedaphic and food preparation situations exist-

Tab le 2 . T o t a l a rea under ce rea l c rops i n t h e S A T coun t r ies i n W e s t A f r i c a and India. (Un i t sexpressed as ' 0 0 0 ha ) .

Country Maize Sorghum Mil let Rice Wheat

India 5900.00 16 015.00 18 351.67 39 504.00 20 859.67

Mal i 91.67 1214.67 204.33 2.00

Niger 10.67 715.67 2 651.67 224.00 2.00

Nigeria 1612.67 5 980.00 4 906.67 311.00 13.67

Senegal 48.33 934.67 74.33

Upper Vol ta 110.00 1 079.34 907.00 42.33

Tab le 3 . T o t a l a rea o f ce rea l c rops in Eastern A f r i c a . (Un i t s expressed as ' 0 0 0 ha ) .

Country Maize Sorghum Mi l le t Rice Wheat

Botswana 71.67 100 10

Ma law i 1033.33 120 45

Zambia 1050.00 80 134.67 2.33 1.67

Kenya 1550.00 209 80.67 7.00 120.67

Sudan 85.00 2705.67 1170.33 8.33 294.00

Tanzania 1300.00 338.33 213.33 180.00 50.00

9

Tab le 1 . S A T and wor ld product ion o f so rghum, mi l le t , ch ickpea, p igeonpea , and g r o u n d n u t Da tarepresent averages fo r t he years 1 9 7 3 , 1 9 7 4 , and 1 9 7 5 . ( Source : FAO, var ious issues).

Area Production Yield

CropSAT World

('000 ha) ('000 ha)SAT/Wor ld

%

SAT

('000 mt)Wor ld

('000 mt)

SAT/World%

SAT('000 kg/ha)

Wor ld('000 kg/ha)

SAT/World%

SorghumMil letsChickpeaPigeonpeaGroundnut

34 553 43 26935 595 70 3529 150 9 9742 669 2 792

14 604 19 084

8051929677

20 08218 1095 4061 777

11 594

52 80046 959

6 0081858

17 868

5539909665

842509591666794

1220667602665936

697698

10085

ing in the sorghum and mi l let areas of West andEast Afr ica.

As the program developed i t became clearthat fur ther strengthening of the research effortwas required. In the early part of Phase II of theUNDP program, i t was decided to strengthenthe team at Kamboinse and to assist w i th theimprovement of physical facil i t ies and the farmlay-out. This helped in fo rg ing links w i th theOAU/SAFGRAD p rog ram. Current ly ICRISAThas four scient ists on its staff in W. Afr icafunded f rom this p rogram — one soi l scientistposted at Kamboinse, and three short ly to beposted to Nigeria, including a sorghum breeder,an agronomist and an entomologist , all w i th anessentially regional program of work.

At Kamboinse, the staff has also been aug-mented by a Striga scientist under a restrictedcore IDRC grant and by the post ing of a corep rog ram economis t to in i t ia te v i l lage levelstudies and studies on adopt ion of improvedtechnology. A core funded entomology posthas also been created. The station wi l l mainlybe concerned w i t h the deve lopment of im-proved sorghum cuit ivars and farming systemsfor the 800 mm rainfall areas of W. Africa. Thelocation of core staff indicates the commi tmentof ICRISAT to a long-term research effort inAfrica.

In v iew of the importance of mil let in theSahelian area, w e a r e negot iat ing an agreementw i th the Government of Niger to site a centernear Niamey. This wi l l deal w i th pearl mi l letimprovement and farming systems, wh ich areessentially concerned w i th mi l le t /groundnuts inthe 600 mm sandy soil si tuations, wh ich are soc o m m o n in W. Africa. Recruitment of some stafffor this si tuat ion is under way.

C o o p e r a t i v e P r o g r a m si n O t h e r A r e a s

In addi t ion to these programs, ICRISAT cur-rently conducts a so rghum program in CentralAmer ica, based at CIMMYT in Mexico, wh ichfo l lows up on a previous program that wasaimed main ly at product ion of cold to lerantsorghums for higher elevation areas. This pro-gram is currently being diversif ied and is produc-ing good qual i ty wh i te sorghums, wh ich areprov ing to be very useful in several countr ies inthe region where sorghum is used as a human

food . Several l ines are already being mul t ip l iedby national programs, and these are useful fo radmixture w i th maize for making tort i l las.

Two years ago i t was recognized that ICRISATshould have a research effort on chickpea out -side the host country, as this w o u l d be valuablein breeding the kabuli type. This program wasbased in the Middle East. A t e a m of one breederand one geneticist is currently based in ICARDA,at Aleppo, Syria. The emphasis in breeding wi l lshift sl ightly in the future towards breeding fordisease resistance.

Role of ICRISAT Scient istsin the Cooperat ive Program

All ICRISAT scientists posted to the CooperativeProgram have a tr ipart i te role to play:

1. They make a direct contr ibut ion to the na-t ional program of the country in wh ichthey serve. This may be large or smal l ,depending on the strength of the nationalresearch program. They f o r m an effectivelink through which genetic material andin format ion f lows to national scientistsf r o m o the r ICRISAT sc ien t i s t s i n t h eCooperat ive Program and f rom ICRISATCenter, Hyderabad.

2. They make an increasing contr ibut ion toregional programs by assisting w i th ex-change of genetic mater ia l , part icularlythrough organization of or assistance w i ththe assembly of regional tr ials, but alsothrough personal contact and informat ionexchange through visits.

3. They have an important role in carryingout exper imentat ion, including conduc't-ingnurser ies, wh ich feed back in format ionto ICRISAT Center and other ICRISAT sci-entists in the Cooperative Program, on theperformance of material under a range ofcl imatic, disease, pest and edaphic condi-t ions. Such in format ion is crucial to bui ld-ing up a good data base and developinglong-term fu l ly integrated strategies forcrop improvement and fa rming systemswork. The exchange is not all one way,e.g. , A f r i ca has a l ready p r o v i d e d t h eCenter program w i th useful genetic mate-rial for development of downy m i l dew re-sistant l ines of pearl mi l let for the Indiansubcontinent.

10

Results f low ing f r om the program to date aremost encouraging in all three roles. The per-formance of improved cult ivars vis-a-vis localland race materials is being assessed and lineshave been developed wh ich are superior to cul-t ivars currently being g rown.

Many l ines hav ing stress resistance havebeen identi f ied and this resistance has beentested across a range of environments. The in-creasing amount of in format ion obtained on thequal i ty characterist ics of improved so rghumand mi l let strains for preparat ion of local foodshas been particularly useful. This is cruciallyimportant in ensuring acceptance of improvedcult ivars by small farmers.

T r a i n i n g

This topic was dealt w i t h earlier in the sym-posium by Dr. Swindale; however I wou ld liketo emphasize that this is a very important areaof activity. Cooperative program scientists, incol laborat ion w i th national scientists, have a very useful role in ident i fy ing technicians andscientists for t ra in ing at ICRISAT Center. Add i -t ional ly, they have init iated t ra in ing and lecturecourses locally in several countr ies to assist instaff development. The tra in ing effort is recog-n ized as be ing o f g r e a t i m p o r t a n c e instrengthening national research efforts and isan activity on wh ich we place very great store.

F u t u r e D e v e l o p m e n t s i n t h eC o o p e r a t i v e P r o g r a m

In spite of the fact that groundnut f igures p rom-inently in Table 1 w i th a hectarage of over 14mi l l ion in the SAT, our program to date over-seas has been negl igible. This is largely be-cause groundnut was added to our mandateonly relatively recently and much effort hasbeen expended to date in bui ld ing up ourg e r m p l a s m base and ac t i v i t i es a t t h e

Hyderabad Center. We are currently investigat-ing the possibi l i ty of ini t iat ing a program ongroundnuts in central Africa and have plans tostart work in West Afr ica, as soon as the centerin Niger is establ ished. Both breed ing andpathology wi l l be covered in the f irst phase,t o g e t h e r h o p e f u l l y w i t h m i c r o b i o l o g i c a lstudies, when funding is identif ied.

In the immediate future we intend to concen-trate on the establ ishment of the Niger Center,wh ich wi l l cater for both groundnut and mil let,expanding our program on farming systems inUpper Volta, and developing a program in thisf ield of endeavor for the sandy soi l , low rainfallareas of W. Africa, basing the program in Niger.We are col laborat ing w i th the Government ofMali in establishing a research center at Cinzanafor work on crop improvement and farming sys-tems in that country.

ICRISAT has been requested by the Heads ofState of Southern African States to develop a regional center and we are actively pursuingthis. A fact-f inding mission wi l l leave for thearea wi th in 3 weeks, and it is hoped that work-ing agreements may evolve f rom this.

We look forward to cooperating ful ly wi th na-tional programs in the great task ahead of help-ing the smal l farmer of l imited means in theSAT. These farmers have been neglected in thepast, but they fo rm a major component of thepopulat ions in mos tSAT areas. Thetask of help-ing them should not be min imized, the roadahead is diff icult and tor tuous, and given thediff icult condit ions unde rwh ich the fa rmers to i l ,progress is unlikely to be punctuated by bigbreakthroughs. The task wi l l take persistence,cont inui ty and patience. I know that we atICRISAT can assist you in your endeavors wi ththe groundnut crop, and I hope that f rom thisconference wi l l come f i rm plans of action andguidel ines on tackl ing the many prob lems weall face in assisting the farmers in the variouscountries represented here.

May I wish the Workshop every success in itsdeliberations.

11

The ICRISAT Groundnut Program

R. W. Gibbons*

G r o u n d n u t s i n W o r l dA g r i c u l t u r e

The cult ivated groundnut , Arachis hypogaea L,is a nat ive of South Amer ica and the crop is nowgrown throughout the tropical and warmtemperate regions of the wor ld . A l thoughgroundnuts are predominant ly a crop of thetropics the approx imate l imits of present com-mercial product ion are between latitudes 40°Nand 40°S.

In 1978, it was est imated that just over 18.92mi l l ion hectares were planted and 18.87 mi l l iontonnes were harvested at an average yield of998 kg/ha (FAO Trade Statistics). Asia is thelargest producer (.10.9 mi l l ion tonnes), fo l lowedby Afr ica (5.2 mi l l ion tonnes). North andCentral America (1.98 mi l l ion tonnes) and SouthAmerica (0.8 mi l l ion tonnes).

Of the indiv idual countr ies, India is the largestproducer in the wor ld (6.2 mi l l ion tonnes), fo l -lowed by China (2.8 mi l l ion tonnes), USA (1.8mi l l ion tonnes) Senegal (1.0 mi l l ion tonnes),Sudan (0.8 mi l l ion tonnes) and Nigeria (0.7mi l l ion tonnes). Approx imate ly 80% of wor ldproduct ion comes f r om the developing coun-tr ies and 67% of the total is produced in theseasonally dry rainfed areas of the semi-aridtropics (SAT).

P r o d u c t i o n C o n s t r a i n t sin t h e S A T

Yields in the SAT are low, around 800-900kg/ha, compared to yields of approximately2500 kg/ha in the developed wor ld (Gibbons1977). The major constraints are pests, dis-eases, and the unrel iable rainfall patterns of theSAT. Apart f rom the natural hazards whichrestrict product ion, there are relatively small

* Program Leader, Groundnut Improvement Pro-g r a m , ICRISAT.

numbers of wel l t rained, specialist g roundnutresearchers available.

A l though groundnuts are often regarded as a cash crop, the necessary inputs are often notavailable to small-scale farmers to control pestsand diseases, for example, even when appro-priate research recommendat ions have beenmade. Very often these recommendat ions havebeen based solely on trials conducted on ex-perimental stations, and not under condit ionswhere the farmer actually grows groundnuts.

Few research programs in the SAT haveconcentrated on breeding for resistance to themain factors which presently l imi t product ion.Some exceptions are the product ion and re-lease of cult ivars resistant to rosette virus inAfrica and cult ivars resistant to drought inSenegal (Gillier 1978).

T h e I C R I S A T G r o u n d n u tI m p r o v e m e n t P r o g r a m

B a c k g r o u n d

In 1974 a team of four consultants was invi ted toHyderabad to review wor ld research needs ofgroundnuts, to consider whether ICRISATought to help meet these needs and, i f so, tosuggest a possible program of internationalresearch. It was concluded that the crop didrequire international research, wou ld be anappropriate subject w i th in the mandates of theinternational research system, and that ICRISATwas the appropriate Center as groundnuts arepr imar i ly a crop of t heSAT(Bun t i nge ta l . 1974).

The consultants considered that the cropneeded international research because (1)groundnut research at national stations in mostcountr ies wou ld benefit f r om internationalcooperat ion, exchange of in format ion, t ra in ing,and in part icular by the format ion of a wor ldgermplasm base, and (2) groundnuts are animportant food crop in many developing na-t ions and the fact that it is also a cash crop

12

should be no bar, as by sell ing crops, farmershelp to feed the nations as a whole.

In 1976 a program of research was presentedto the Governing Board of ICRISAT. The reportwas accepted, and the recrui tment of staffcommenced (Gibbons 1976).

Research Organizat ion

Within the program, at the research center inHyderabad, there are a number of subprogramswhich include breeding, pathology, cytogene-tics, microbio logy, entomology and physi-ology. The germplasm subprogram was or igi-nally in the Groundnut Improvement Programbut is n o w part of the Genetic Resources Unit,which has assumed responsibi l i ty for all themandate crops of the Institute.

The consultants also decided that generalagronomic studies should not fo rm a major partof the program because such problems werelocale-specific and were the responsibi l i ty ofnational programs. The consultants also re-commended that a l though ICRISAT should beful ly in formed about the insect pests ofgroundnuts, no special p rogram should beformulated (Bunting eta l . 1974). However, sincethis report it has become apparent that insectpests are a serious wor ldw ide prob lem, bothdirectly and as vectors of v irus diseases, and a decision has been taken to increase entomo-logical research at ICRISAT f rom 1981.

Staffing of the center program is now almostcomplete, except for the physiology programwhich has only very recently commenced.

Object ives

The main objective is to produce high yieldingbreeding lines w i th resistance to the mainfactors presently l imi t ing product ion. It is notthe intent ion to produce f in ished cult ivars, butrather to supply germplasm and breeding lineson wh ich fur ther selection can be practiced incooperat ing countries. For th is, there is a needto know the exact requirements of cooperat ingcountries. These requirements vary greatly,even wi th in a country. For example in theSudan, large-seeded, long season groundnutsare g rown under irr igat ion in Wad Medani forexport ; but under rainfed condi t ions farmerscult ivate short season cult ivars that are moreadapted to those condi t ions (Osman 1978). In

Malawi , long season groundnuts , pr imar i ly forthe confectionary export trade, are g rown in theplateau areas; cult ivars for oi l crushing aregrown in the lake shore areas; and short seasoncultivars are adapted to the l ow elevat ion, drierand hotter areas in the southern part of thecountry (Gibbons 1972).

S p e c i f i c R e s e a r c h G o a l s

The program has emphasized the fo l low ingspecific research goals:

Breeding f o r Resistance to Ma jo rDiseases and Pests

The most important foliar diseases causingsevere yield losses on a wor ldwide basis are theleaf spots (Cercospora arachidicola and Cerco-sporidium personatum) and rust (Pucciniaarachidis). Bunting et al. (1974) conservativelyestimated that the leaf spot fungi alone causethe loss of about 3 mi l l ion tonnes of kernels peryear. Losses in kernel yields of around 10%have been estimated in the USA, even whenfungicides are rout inely appl ied (Jackson andBell 1969). In the SAT where chemical control isoften not used, losses in excess of 50% arecommonplace (Garren and Jackson 1973). Rustof groundnuts has become a wor ldwide prob-lem since 1969 (Subrahmanyam et al. 1979).

Intensive programs have been started tosearch for resistance to these diseases, both inthe cult ivated and wi ld species of the genus,and to incorporate this resistance into highyielding and commercial ly accepted cultivars(Nigam et al., Subrahmanyam et al., Nevil l — this conference).

Programs are also being developed to breedfor resistance to Aspergillus f lavus, which pro-duces a toxic metabol i te that affects humanhealth. Breeding lines possessing dry seedresistant to penetration by this fungus havebeen identif ied in the USA (Mixon and Rogers1973) and are being utilized in the breedingprogram.

The germplasm collection is also beingscreened for sources of resistance to suchcommonly occurr ing fungi as Aspergillus niger, Fusarium sp, Pythium sp, and Rhizoctonia sp.

Virus diseases of groundnuts are c o m m o nand serious in the SAT. The major virus dis-

13

eases being investigated presently at ICRISATare bud necrosis, caused by tomato spotted wi l tv irus (TSWV), and peanut mott le v i rus (PMV).The germpiasm collection is being screened forsources of resistance, and other methods ofcontrol are also being investigated (Ghanekar;Amin and Mohammad — this conference).

A l though insect pests are often l imi ted intheir d is t r ibut ion, some are of wor ldw ide dis-t r ibut ion and importance. A m o n g the latter arespecies of aphids, jassids, thr ips and termites.Some of these species occur at the ICRISATresearch center and germpiasm is beingscreened for sources of resistance in specialpesticide-free areas located on the researchfarm at Hyderabad.

Breeding for Earliness, High Yieldand for the Farming Systems

There is a need to generate high y ie ld ing lineswhich are adapted to the harsh condi t ions of theSAT. As already stated, i t wou ld be important toincorporate into these lines resistance to themajor constraints and stabil i ty of y ie ld overyears. However, not every environment hassevere disease or erratic rainfall constraints, sohigh y ie ld per se is also important.

Earliness is also an impor tant object ive, asgroundnuts f i t into relay or sequential croppingsystems where residual moisture is availablef rom the preceding crop. Wi th the advent ofshort durat ion rice cult ivars, large areas ofSoutheast Asia are now able to g row more thanone crop per year. Rice, fo l lowed by rice, or anupland crop is now a common practice andgroundnuts wou ld f i t wel l in this system.Sources of earliness are being util ized in thebreeding program (Nigam et al. — t h i s confer-ence).

Groundnuts are also common ly intercrop-ped, part icularly in India and Africa. In theGuinea Savanna zone of Nigeria, only 16% ofthe total area is planted as sole crop groundnuts(Kassam 1976). The Groundnut ImprovementProgram is cooperat ing w i th the ICRISAT Farm-ing Systems Research Program in ident i fy ingsuperior g roundnut cult ivars for the intercrop-ping si tuat ion (Reddy et al. — this conference).

Increas ing BiologicalN i t rogen Fixat ion

The groundnut is an efficient f ixer of ni t rogen

and at tempts are being made to manipulateboth the Rhizobium and the host plant compo-nent of symbiosis to increase ni trogen f ixat ion,and hence groundnut yields. There is also a beneficial effect on the subsequent crop f rom a wel l nodulated groundnut crop (Nambiar andDart — this conference).

Exploiting the Wild Speciesof Arachis

A major component of the program is theutil ization of genes f r om the w i ld Arachis species to improve the commerc ia l g roundnutcrop. Resistance to fungal diseases, pests, v i -ruses and drought occur in these species butgenetic manipulat ion is required to incorpo-rate these characters into the cult ivatedgroundnut because of differences in ploidylevels and other barriers to interspecific hy-bridization (Moss 1980).

Exploi t ing Physiological Charactersfo r Groundnut Imp rovemen t

This is the last of the programs to be staffed. Theresearch program wi l l be formulated in the verynear futu re and a major part w i l l be to study andexploit characters associated w i th drought re-sistance.

L i n k a g e s

Internat iona l Coopera t ion

The ICRISAT program has been, and stilt is, de-veloping linkages with other institutions conduct-ing research on an international or regional basis.Cooperative programs have been fo rmed w i thNorth Carolina State Universi ty on the transferof groundnut germpiasm, biological ni t rogenf ixat ion research and the uti l ization of w i l dArachis species in the improvement of thecult ivated groundnut . A jo in t p rogram has beenformed between ICRISAT and the USDA inscreening all known sources of resistance torust at the ICRISAT research center. The Gov-ernment of Japan has prov ided visi t ing scien-tists and facil it ies for research on viruses. TheInternational Board for Plant Genetic Resources(IBPGR), the germpiasm center in Brazil(CENARGEN), ICRISAT, and national scientists

14

f rom the USA and other countr ies are cooperat-ing on groundnut germplasm collections inSouth America. Research on the uti l ization ofw i ld species of Arachis, carried out at theUniversity of Reading and f inanced by theBritish Government, has been of immense helpin the ICRISAT program.

Other linkages are being investigated andthere is particular interest in cooperat ing wi thnon-groundnut g rowing countries in the inves-t igat ion of viruses and whether races of impor-tant fungi occur. These investigations cannot becarried out in India because of quarant ine regu-lations and the risks of introducing new dis-eases into groundnut g rowing countries.

Coopera t ion w i t h Na t iona l Programs

The program has developed very close linkswi th the Directorate of Oilseeds Research inIndia. The entire Indian germplasm collectionwas placed at the disposal of ICRISAT andcooperative links have been formed wi th Indianuniversit ies and research stations. A new na-t ional center for groundnut research has re-cently been created and located in the state ofGujarat, the largest groundnut producing areaof India. It is envisaged that close cooperat ionwi l l develop between ICRISAT and this center.

In the relatively short t ime that the inter-national program has been operating, links wi thnational programs interested in groundnut re-search have developed satisfactorily. There isnow a need though to intensify and expandthese links as breeding material is now becom-ing available for widespread distr ibut ion.

The t ra in ing facilit ies in groundnut researchat ICRISAT are also becoming available andalready personnel f rom several countr ies haveattended courses in such subjects as hybridiza-t ion techniques, disease scor ing methodologyand virological techniques. It is intended thatthese facil i t ies should be expanded in thefuture.

T h e F u t u r e

There is stil l a long way to go before markedsuccess can be achieved for the underpr iv i legedfarmer of the SAT. It is felt however that themajor research emphasis on stable diseaseresistance and high yield wi l l begin to be

achieved in the not too distant future. TheCenter program needs to be intensif ied, part icu-larly in the fields of entomological andphysiological research, and more cooperat ionwi th national programs is required. In 1981 a regional program is planned for Eastern andCentral Afr ica, and also in 1981 a second re-gional program wi l l be set up in West Africa.These regional programs wi l l init ial ly be staffedby a breeder and a pathologist and be fundedf rom the core budget. If noncore funding be-comes available, then a microbiologist wi l l beadded to each team.

References

B U N T I N G , A . H., GREGORY, W. C , M A U B O U S S I N , J . C ,

and R Y A N , J. G. 1974. A proposal fo r research ongroundnuts (Arachis) by ICRISAT. ICRISAT 38 pp.(Mimeographed) , Patancheru, A. P., India.

GARREN, K. H., and J A C K S O N , C. R. 1973. Peanut

Diseases. Chapter 13 in Peanuts-Culture and Uses.Amer ican Peanut Research and Education Associa-t ion .

GIBBONS, R. W. 1972. Peanut disease control inMa law i , Central Afr ica. Proceedings, Amer icanPeanut Research and Education Associat ion 4 : 1 - 7 .

G IBBONS, R. W. 1976. Groundnut improvementp rogram — pr ior i t ies and strategies. ICRISAT.(Mimeographed) , Patancheru, A. P., India.

G IBBONS, R. W. 1977. An internat ional approach topeanut improvement . Proceedings, Amer icanPeanut Research and Education Associat ion 9: 9 7 -100.

GILLIER, P. 1978. Nouvel le l imi tes cultures d 'Arachideresist ante a la secheresse et a la rosette. Oleaglneux33: 2 5 - 2 8 .

J A C K S O N , C. R., and BELL, D. K. 1969. Cercospora

leafspots. In Diseases of peanut caused by fung i .Universi ty of Georgia Agr icu l tura l Experiment Sta-t ion research bul let in 56. 137 pp.

KASSAM, A. H. 1976. Crops of the West Afr ican Semi-Ar id Tropics. ICRISAT. Patancheru, A. P., India.

M I X O N , A. C , and ROGERS, K. M. 1973. Peanuts

15

resistant to seed invasion by Aspergillus flavus. Oleagineux 28: 8586.

M o s s , J. P. 1980. W i ld species in the improvement ofgroundnuts . Advances in Legume Science (eds.Summer f ie ld and Bunt ing). Pages 525-535 in Vol 1 of the Proceedings of the Internat ional LegumeConference, Kew, England, 1978.

O S M A N , A. B. 1978. Peanut product ion in t he Sudan.Page 12 in Virginia-Carol ina Peanut News.

SUBRAHMANYAM, P., GIBBONS, R. W., NlGAM, S. N., and

R A O , V. R. 1978. Screening methods and fur thersources of resistance to peanut rust. Abstract inProceedings, Amer ican Peanut Research and Edu-cation Associat ion 10(1): 64.

16

Session 2

Research Organizat ionand Deve lopment

Chai rman: C. Harkness Rapporteurs: J. P. MossD. C. Sastr i

Indian Coordinated Research Projecton Oilseeds w i th Special Reference to Groundnut

V i k r a m S i n g h *

The evolut ion of agricultural research in Indiacommenced as early as 1870. Its developmentto the present coordinated research approachhas been expedited by two almost s imul tane-ous developments: f irst, the acceptance of theUppal Commit tee report (1954-56) to re-gionalize research on cotton, oilseeds, and mi l -lets; and the second, the successful experienceof the coordinated approach applied for the firstt ime in maize in the late 1950's. It has beenrefined since then and extended to all the crops,including oilseeds.

The cardinal phi losophy and the special fea-tures of the coordinated research as developedover the years (Singh 1980 a), and common toall projects, are:

1. A mult id iscipl inary approach to problemsolutions.

2. Free exchange and f l ow of material , in-fo rmat ion, and ideas among researchworkers.

3. Compulsory analysis, report, and discus-sion of research results pr ior to the futureplanning of the next season/year pro-gram.

4. Planning the technical program and re-search methods by c o m m o n discussionand consultat ion among research workersdur ing annual workshop/meet ings.

The fo l lowing six special features also apply:1. The project/program operates on a na-

t ional scale under the direct supervision ofthe Indian Council of Agr icul tural Research(ICAR).

2. Al l participating institutions/organizationsin the country work as a team to impart a national character to it.

3. The project/program has a ful l-t ime ProjectCoord ina tor /Pr inc ipa l Invest igator tocoordinate, supervise, and watch the pro-

* Project Director, Directorate of Oilseeds Research,ICAR, Rajendranagar, Hyderabad 500 030, AndhraPradesh, India.

gress for report ing to Council/Govern-ment.

4. The state provides the required land andlaboratory facil it ies for the cooperat ingcenter(s) located w i th in its bounds.

5. The research investment is shared be-tween the Council and state on a 3:1 basis.

6. A l l major disciplines are represented on theproject work on the basis of equivalenceand mutual ism.

The Oilseeds Project

The All India Coordinated Research Project onOilseeds, wh ich was established in 1967, wasraised to the status of Directorate of OilseedsResearch (DOR) on August 1, 1977 in order toenlarge its scope and activities (Vikram Singh1978). The main objective of the Oilseeds Re-search Project is to coordinate, encourage, in-itiate and plan research activites wi th a v iew toprovid ing a research base which would result inan increase in the product iv i ty and stabilizedproduct ion of oilseeds in India.

The Groundnut Program

The specific objectives of the Directorate'sgroundnut program are:

1. Development of high y ie ld ing varietiespossessing resistance/field tolerance todiseases and pests of economic impor-tance for the different groundnut g row ingagroecological zones.

2. Development of product ion technologyfor max imum yield exploi tat ion under irr i-gated and unirr igated condi t ions in diffe-rent groundnut g rowing zones.

3. Development of s imple and cheaper cropprotection technology w i th an emphasison integrated control of the disease-pestcomplex.

19

4. Demonstrat ion of the proven research re-sults through onfarm trials for the benefi tof farmers as wel l as extension workers.

5. Identif ication of the stable sources of resis-tance to diseases and pests, and otherdesirable agronomic traits in the germ-p lasm, and their use in future breedingprograms.

6. Product ion and maintenance of a cont inu-ous supply of breeder's seed for mul t ip l i -cation into fur ther categories of seeds forul t imate supply to the farmers.

7. Resolving any other problems.The number of main and sub-centers for all

oi lseed crops is n o w 62. Of these, 17 aredeployed for research on the groundnut crop. Inaddi t ion, suppor t f r o m other centers has beenenlisted. Act ive cooperat ion of scientists in theGroundnut Program of the International CropsResearch Insitute for the Semi-Arid Tropics(ICRISAT) since the beginning of the programin 1976 has been noteworthy. Addi t ional ly, theDirectorate of Oilseeds Research derives advan-tage f rom the experiences of other CoordinatedProjects (such as the Model AgronomicScheme, Dryland Farming Project, CroppingPattern and Land Use Project, and Crop Projectssuch as pulses, sorghum, mil lets, and sugarcanewherein oilseed crops fo rm a part of croppingpattern) and the Institute like the Central Ar idZone Research Institute, Jodhpur, and CentralSoi l Salinity Research Institute, Karnal.

The scientif ic strength at a ma in center in theNational Oilseeds Research Project normal lyconsists of a breeder, agronomist , plantpathologist , entomologist , biochemist, and a statistician, wh i le that of subcenter is l imited to

a breeder, or a max imum of assistant ag-ronomist in addit ion.

In 1979, the National Research Centre forG r o u n d n u t (NRCG) was es tab l i shed atJunagadh, w i th a mandate to generate anddistr ibute breeding material at early stages andto engage in basic research w i th a v iew to breakyield barriers in the groundnut crop.

The twoproceduresdeve loped fo rg roundnu tresearch for var ious disciplines are:

Four-Tier Sys tem of Test ing

For rapid mult i locat ion test ing of promis ingbreeding material and to assess the material 'ssuitabil i ty for different agroecological zones oradaptabil i ty at national level, each of the prom-ising lines enter the Initial Yield EvaluationTrials (Stage I). Depending upon performance,an entry can rise up to the National EvaluationTrial after wh ich it is identi f ied by the researchgroup as a potential variety. The period oftest ing and promot ion f rom one stage to thenext higher are given in Table 1.

After an entry has been identif ied as promis-ing, a V stage (Minikit/District Level Trial) as thefinal stage between the identif ication and f inalrelease of the variety, has been introduced since1979.

Deve lopmen t o f Agro -Pro tec t ionTechnology

In thediscip l ines of agronomy, plant pathology,and entomology, s imple to complex coordi-nated experiments are formula ted and im-plemented uni formly at all the stations.

20

Table 1. Four-tier system of testing groundnuts.

Stage Seasons of t r ia l

No. Name M a x i m u m M i n i m u m Remarks

I

II

III

IV

Init ial Yie ld Evalua-t ion Trial (IYET)Prel iminary VarietalTrial (PVT)Coordinated VarietalTrial (CVT)Nat ional Evaluat ionTr ia l (NET)

2

2

2

1

1

1

2

1

An entry f r o m IYET/PVTcan be p romoted to the nextstage after a one-season t r ia l ,i f i ts average y ie ld exceedsthe check var iety by 25%.

Location-specific tr ials under the category ofstation tr ials are also discussed and finalized fordifferent stations.

Groundnut ResearchAchievements

The dependence of groundnut cult ivat ion onhighly erratic rainfal l , susceptibi l i ty to devastat-ing pests and diseases, and the l imited capacityof the groundnut g rower make groundnut re-search rather more chal lenging.

Particular achievements in the groundnutprogram are:

Germp lasm

The groundnut program of DOR has shared itsentire col lection (4968 entries) w i th ICRISAT(Anon. 1979), wh ich was designated as thewor ld center for col lection, preservation anddocumentat ion of the genus Arachis by theInternational Board for Plant Genetic Resources(IBPGR). The groundnut program currently hasaccess to more than 9000 accessions of theICRISAT Center.

The National Research Centre for Groundnutis being developed as the second importantcenter for maintenance and evaluation ofgroundnut germplasm in the country.

The program in its mult i locat ion test ing ofgermplasm/breeding material has identi f ied a large number of lines resistant to one or morepests/diseases. These are being evaluatedfurther in the mult i locat ion uni form diseasenurseries (Vikram Singh 1979). The most nota-ble f indings are listed in Table 2.

Table 2. Some results of multilocation tastingof germplasm/breeding material.

Source/line Resistant/tolerant to

G 201 Leaf spotAh 7724Ah 7747 Leaf spot, rust*EC76446Ah 7795 Aphid, JassidsAh 7799 Aphid, Leaf minerAh 7983 White grub

* Also reported by R. W. Gibbons (1979).

Var ie t ies Released fo r Cu l t iva t ion

Since 1967, some 28 varieties belonging to thethree broad growth habit groups (16 in bunch, 5 in semi-spreading, and 7 in spreading type)have been released for different adaptabil i tyzones. Of these, M-13 and TG-1 (Vikram) are theonly t w o varieties that have been released bythe Central Variety Release Commit tee at na-t ional level. These t w o varieties when evaluatedon farmers ' f ields across 3 to 5 groundnutgrowing States, on average yielded 74 and 5 1 %more than local varieties (VMA 1978).

Agro-Pro tec t ion Technology

The opt imum agro-protection technology for thedifferent agrocl imatic zones in respect of avail-able varieties has been worked out by dif ferentcooperat ing centers. Agronomic and plant pro-tection research f indings have been recentlydiscussed by Singh (1979). Salient researchf indings wi th recent addit ions are:

Agronomic Practices

a. Plant stand. The use of op t imum seed ratesand control of seedling diseases is theeasiest and surest way to higher yields.

b. Field preparat ion. An increase in depth ofp lowing f rom 10 cm to 30 cm has givensignif icant yield increases in the red soils ofAndhra Pradesh, pr imar i ly due to increasedwater intake and increased root penetrationactivity (Table 3).

c. Groundnut nutr i t ion. Except for some areaslike the Saurashtra region of Gujarat and theKurnool district of Andhra Pradesh, wherefert i l izer is being applied by farmers (in somecases much more than the recommendedlevels), the level of nutr ients applied rangesf rom low to ni l . Results obtained in thegroundnut program suggest higher levels ofnutr i t ion in respect of N, P, and some minorelements (Singh 1980b). Gypsum applied at250 kg/ha has given signif icantly higheryields.

d. Package of practices. Dur ing the past 2 to 3 years, the relevance and effectiveness of theresearch results when applied to a largescale area has been engaging the attentionof oilseed research workers. Results f rommult i locat ion tr ials conducted to compare

21

the recommended package of practices w i t hthe farmer 's method (local) have shown thatgroundnut yields can be doubled by adop-t ion of the package of practices (Table 4).

The signif icant yield increase obtained f romfo l lowing the recommended package of prac-tices is further conf i rmed by the results f r om thedemonstrat ion trials conducted on farmers 'f ields by the State Departments of Agr icul ture(Singh 1979), and by the results of a surveyundertaken on the causes of low yields. Thesurvey clearly showed that wherever farmersadopted recommended practices (not in ful l) ,the district average groundnut yields have been4100 kg/ha as against the average yield of1000 to 1100 kg/ha where farmers did not adoptthe recommended practices (Reddy and Reddi1979).

Protection-Technology

Large reductions in yield due to attacks bydiseases and pests rank second only to thereductions due to unfavorable weather.

Due to the unavailabi l i ty of resistant/tolerantvarieties to major diseases and pests and keep-ing in mind the l imi ted investment capacity ofthe farmer, the Project f rom the very beginninghas emphasized the development of relativelysimple and cheaper control measures. Controlmeasures for all the important diseases andpests i.e., leaf spots (both early and late),groundnut rust, various rots, and aphid, leafminer and wh i te grub have been determined.

At current prices, most of the control mea-sures (operational cost included) cost less thanRs.150/ha and have resulted in signif icant yield

22

Table 3. Effect of depth of plowing on groundnut yields in th e rod soils of Andhra Pradesh. a Yield inquintals/ha (1q = 100 kg).

Treat. year Residual effects

Plowing 1972 1973 1974 1975

Shallow (10 cm)Deep (30 cm)

CD

4.25.42.1

8.611.72.2

5.78.22.1

13.314.2NS

a. Data from Dryland Farming Project.

Table 4. Average yield response of two groundnut varieti es under different management practicesat Ludhlana (Directorate of Oilseeds Research 1980).

Pod yield (kg/ha)b

% Increase % IncreaseTreatment M-13 over (A) PG-1 over (A)

(A) Local practices 1058.33 974.67(B) Recommended package of practices 2468.33 133.23 2313.00 137.31(C) B minus seed treatment and 2130.00 101.26 2057.00 111.05

termite control(D) B at 75% seed rate 2302.00 117.51 2132.00 118.74(E) B minus fertilizers 1964.33 85.61 1872.33 92.10(F) B minus weed control 1667.00 57.51 1815.33 86.25(G) B minus protective irrigation 1645.67 55.50 1770.67 81.67(H) B minus plant protection 2074.67 96.03 1699.33 74.35(I) B but less durationb 1838.67 73.73 1939.67 99.01

a. Average of three kharif season trials (1977-79).b. The crop was harvested 15 and 20 days earlier than the normal harvest time for M-13 and PG-1, respectively, in order to vacate

the field for next crop.

increases and a net return of more thanRs. 400/ha. Control l ing wh i te grub costsRs. 280/ha, but the yield increase is more than100%. Net returns in the case of rust controlhave ranged f rom Rs. 200 to 370/ha.

Other No tab le Aspects

Attempts at hybridizat ion in groundnut in thepast have had a very l ow success rate (about10%). This has now largely been overcome andthe success rate has increased to more than50%, and somet imes it has been over 80%.Some success towards identif ication of thesuccessful one f rom the accidentally selfed one,on the basis of pod morphology, has been made(Raman 1980). However, successful fert i l izationof both the proximal and distal ovules has notbeen accomplished in all cases.

The higher success rate of hybridization hashelped to achieve a long overdue project man-date, i.e., free exchange and f low of groundnutbreeding material. The large scale exchange ofbreeding material for the first t ime was ac-compl ished in the 1979 groundnut season,wherein the contr ibut ion f rom the ICRISATGroundnut Program was largest.

The Future Strategy

The research goal is stabilized groundnut pro-duct ion in the country. Fortunately, the nationalresearch infrastructure already developed forthe groundnut program, reinforced by the t w odevelopments in the recent past — i.e., theestabl ishment of the Groundnut Program atICRISAT, Hyderabad, in 1976 and the estab-l ishment of the National Research Centre forGroundnut at Junagadh (Gujarat) in 1979 — has the capacity to meet the future challenges.What is required now is reorganization andreallocation of priori t ies, and the strengtheningof weak links in the program.

It is believed that these could be achieved by:

1. Identif ication of regional/national prob-lems of a short and long-term nature; thef ix ing of priorit ies and assignment thereofto specific worker(s)/center(s) as againstthe present practice of everyone work ingon each and every problem.

2. Identif ication of centers and strengtheningthereof, for the generat ion and early shar-

ing of breeding material having desirabletraits like disease and pest resistance,drought tolerance, early or late matur i tygroups, and interspecific hybridization.

3. Strengthening and development of pro-grams in plant pathology and entomologywi th emphasis on identif ication of sourcesof stable resistance to var ious pests,immuno-genet ic studies, eco-biology ofthe pest, integrated pest/disease man-agement and prognosis of diseases andpests of economic importance.

4. Establishment of a center for intensifica-t ion of research in all disciplines for irri-gated groundnuts — an aspect hi thertonot covered in the national g roundnutprogram.

5. Strengthening and development of re-search in plant physiology and microbio l -ogy. NRCG (Junagadh) and ICRISAT havebeen identif ied as the main centers forthese two programs.

6. Identif ication of centers for intensivestudies on groundnut yield-weather rela-t ionships; detailed and in-depth studies onmicronutr ient-nutr i t ion of the groundnutcrop; and ni trogen nutr i t ion of groundnutin relation to rhizobial inoculat ion andvarieties.

7. Introduct ion of compulsory on-the-farmtrial programs at each center.

8. Standards and measures to improve thequality of experiments and therefore thevalidity of results.

Many of the basic studies are being carriedout and wi l l be carried out in the future atICRISAT, f r om which the national program hasderived/wi l l derive advantage. The existing re-lat ionship between the national groundnutprogram and the ICRISAT groundnut programis very close and cooperative. It is hoped thatboth wi l l benefit f r om each other and the resultsthat f low f rom such joint efforts wi l l benefit theult imate consumer — the groundnut grower.

References

A N O N . 1979. The current status of g roundnutgermplasm at ICRISAT. Paper circulated to m e m -

23

bers of IBPGR/ICRISAT ad-hoc Work ing Group onGroundnut Germp lasm, at the Group Meet ing atICRISAT, Hyderabad, 2 4 - 2 6 Sept 1979. (M imeoICRISAT) 21 pp.

G IBBONS, R. W. 1980. Groundnut improvement re-search technology fo r the semi-ar id t ropics. Pages27-37 in Proceedings of the Inaugural Sympos iumon Development and Transfer o f Technology fo r theRainfed Agr icu l ture and SAT Farmer, 28 Aug-1 Sept1979, ICRISAT, Patancheru, A.P., India.

R A M A N , V. S. 1980. A note on g roundnu t hy-b r id i za t ion—percen tage of success and Iden-t i f icat ion of crossed pod. (Personal commun ica t ion ,4 Augus t 1980).

REDOI , G. H. S., and REDOY, A. D. 1979. A survey reportof causes of l o w g roundnu t y ie ld in six distr icts ofAndhra Pradesh. APAU, Rajendranagar, Hyderabad.77 pp.

S I N G H , V I K R A M . 1978. Directorate of Oilseeds Re-

search, its object ives, organizat ion and fu ture plan

of work , (DOR mimeo) 21 pp.

S I N G H , V I K R A M . 1979. Current status of oi lseeds re-search in India, presented at nat ional seminar onresearch and deve lopment strategies for oi lseedproduct ion in India, IARI, New Delh i , 7 -10 Nov 1979.(DOR Mimeo) . 65 pp .

S I N G H , V I K R A M . 1980a. Development o f agr icul tureresearch in India w i t h special reference to coord i -nated mult i -d iscipl inary approach. Lecture del i -vered to the ARS Probationers, NAARM, Hyderabad,Feb 1980.

S I N G H , V I K R A M . 1980b. Ag ronom ic potent ial o f oi lseedcrops. Lecture del ivered to FAI Executive Trainees atV ikram Hote l , New Delhi , 5 Apr i l 1980. (FAI Mimeo)27 pp.

VMA. 1978. Annua l report of the research and de-ve lopment wo rk done by the Vanaspati Manufac-turers ' Associat ion of India, Bombay.

24

Role and Function of the IRHOin Groundnut Research and Development

P. Gil l ier*

Structures

The IRHO is a private nonprof i t organizationsponsored by the French Government and in-corporated into the GARDAT (Study and Re-search Group for the Development of TropicalAgronomy) .

Its head office is in Paris, where the GeneralDirectorate, Research Department, and thePlant and Technology Departments (oil pa lm,coconut and annual oil crops) are also located.

The scientific departments and laboratoriesare at Montpel l ier. They coordinate the outsideactivities which are carried out in various formsin the tropical zone.

This structure is assisted by a Documentat ionand Publication Department, which distr ibutesin 75 countr ies in French, English, and Spanish a month ly review called OLEAGINEUX whichspecializes in oil crops.

Objectives and Action

The IRHO is devoted to the development oftropical oil plants. It deals w i th the oil pa lm,coconut, and annual oil crops in the f rameworkof international cooperat ion. Its activities rangefrom scientific research to the practical applica-t ion of its results. It contributes to technical andeconomic promot ions in the countr ies con-cerned.

The technical aid and assistance made avail-able by IRHO is solidly based on experienceacquired in the tropical zone in numerous re-search stations, plantations and oil mi l ls inmore than thir ty countr ies for over thirty years.

* Director, Annual Oil Crops Department, IRHO, (In-s t i t u t de Reche rche p u r les H u i l e s e tOleagineux — Research Inst i tute for Oil and Oi l -seeds). 11 Square Petrarque, 7501L, Paris, France.

Means of Interventionand Resources

The IRHO can call on 85 technical executives(scientists and research workers) cover ing a very w ide range of discipl ines: pedology, ecol-ogy, genetics, cytology, physiology, chemistryand biochemistry, agronomy, phytopathology,virology, entomology, statistics and sof twaretechnology and economics; this does not in-clude the administrat ive executives, Plantationand Project Directors, and extension workers.

The IRHO can intervene in many areas, includ-ing agronomic research in the strict sense(conception, control and interpretation of ex-periments); specialized studies in pedology,cl imatology, mineral nutr i t ion, phytosanitarytreatments; creation of new varieties and sup-ply of selected seeds; contr ibut ing to designingdevelopment plans; technical control of planta-t ions; advice and control in bui ld ing and operat-ing oil mi l ls ; specialization of scientists; andpre-extension work on techniques developed inthe stations, in rural areas.

These interventions occur in the f rameworkof general cooperat ion agreements existingbetween the French Government and othercountries (in general, Francophone Africancountries) in the f ramework of a private agree-ment between the IRHO and the governmentconcerned, or in the f ramework of private con-tracts between the IRHO and various researchor development bodies, or international organi-zations.

In 1980, for a budget of US$ 16.5 mi l l ion, a breakdown of the or ig in of the credits is: f romFrench governmental organizations, 25%; f romforeign beneficiary states, other states and in-ternational organizations, 12%; and the lRHO'sown resources and private credits, 63%.

Created immediately after the war, the IRHOonly began to work on annual oi l crops, and onthe groundnut in particular, in 1948. The Insti-

25

tu te has thus been work ing for exactly 32 yearson these plants in the Mediterranean area.Certain basic techniques were created there inthe laboratory (leaf diagnosis, g rowth mea-surements etc) and then in West and CentralAfrica. We are n o w mov ing in to Southern Afr icaand other countr ies that have demonstrated aninterest.

Groundnut and annual oil crops representonly 20% of the IRHO's activit ies. The basicf ramework of our intervent ions in this area, andwhere they now stand are described be low:

Conditions for interventionand Localization

The Annual Oil Crops Department is work ing onthe groundnut almost exclusively in Fran-cophone Africa. Before these states becameindependent, the Department had its own re-search stations, or specialised sections, in var i -ous countr ies and took part in the generalagronomic research effort in this area. At thatt ime, this was coordinated on the level of theAOF and AEF federations.

A f t e r i n d e p e n d e n c e , rev i s ion o f t h earrangements lent the var ious interventions a more national character; coordinat ion of thevar ious arrangements was lessened. Fortu-nately, present relations between states, andprivi leged links between the research workersthemselves, have to a great extent preventedthe same work being done twice over.

The IRHO has pursued its activit ies in theareas of applied agronomic research, pre-extension work and seed mult ip l icat ion. Thelatter t w o activit ies are essentially l inked toapply ing research results. To date, we operatein six countr ies: Senegal, Mal i , Guinea Bissau,Upper Vol ta, Niger, Tchad.

Depending on the si tuat ions, the work to becarried out, and the type of contract s igned, theresearch workers or technical advisors are as-signed to precise programs or projects. Therearethus many methods of work. For example, insome cases on ly the research workers ' salariesand t ransport expenses to the work site arecovered by the IRHO; the host governmentensures the w h o l e operat ion. In other cases, thesalary and operat ion are entirely at the expenseof the IRHO wh ich manages the p rogram or theoperat ion.

For a company or government , the advantagein work ing w i th our Institute stems mainly f romthe support and logistical backup wh ich theisolated agent on a station or the technicaladvisor assigned to a specific operat ion canreceive, as wel l as the rather considerable rangeof oi l crop scientists or technicians available tohelp solve their problems.

Al though the staff of the Annual Oil CropsDepartment numbers only about 20 scientistsand technicians, the IRHO tries to satisfy allrequests in funct ion of the states' require-ments. It answers calls for tenders for thesupply of services in its area, and ensures a certain number of study, technical advice orconsultant missions th roughout the wor ld .

Range of Activities

Some of the past or present activit ies pursuedby our agents in the f ramework of contracts oragreements are described below. In most cases,they are not exclusive to the IRHO, as they arepart of a team undertaking, bu tourpar t i c ipa t ionis often essential, and justif ies our c la imingthem as part of our knowledge, and a result ofour experience.

Research

Physiology

From 1956, systematic work has been pursuedon groundnut drought resistance, its precisemeasurement, evaluation of sensit ivity stages,and development of rapid tests enabl ing pre-cise evaluation of the plants' reactions to waterstress. This aspect of research conducted inBenin and Senegal was mainly designed toenable practical sort ing and selection to bedone on progenies, bulks or populat ions, and tobetter evaluate the intrinsic value of choices.

At present, we have in-depth knowledge ofthe plant in th is particular f ie ld , .author iz ingjudicious manipulat ions. This can eventual lyserve other species wi th simi lar characteristics.

Mineral Nutrition

From 1948, the first work done by the IRHO ongroundnut dealt w i th the plant 's mineral nutr i -t ion. The groundnut was then considered to be

26

capricious in response and often unprof i tablefor mineral manur ing.

Precise and methodical analysis of absorp-t ion condi t ions f o r t he var ious mineral elementsdur ing g row th , l inked to plant product iv i ty,enabled nutr i t ion standards to be specified(critical level and response curve).

Numerous fertil izer trials carried out in morethan 10 producing countr ies, fo l lowed up by theleaf diagnosis technique, conf i rmed the val idi tyof these standards. We now have a valuablebasic element for evaluating manur ing needsand mineral correctives to be applied to thecrops. This technique is used to control theevolut ion of the plant's nutr i t ion dur ing rotat ionand in development projects where applicationof an economical fertil izer fu l f i l l ing the plant'sstrict needs is the foremost requirement.

A lmost unknown and unused before 1948,mineral manur ing is now wide ly used in WestAfrica, where both s imple and complex for-mulae have proved their prof i tabi l i ty w i t h con-stant results.

Agricultural Techniques and Packaging

Depending on the country, the crop types, andthe varieties used, s imple g row ing techniqueshave been tested and proposed for wider appli-cation.

The IRHO has made a signif icant contr ibut ionto the study of fa l low land (durat ion, t reatment) ,rotat ion, sowing density, fertil izer appl icat ion,harvesting etc. Prototypes of small-scaleequipment like ferti l izer-spreaders, thresher,shellers, and groundnut washers have beenproduced and distr ibuted. Simple themesapplicable by the growers under the extensionworkers ' control have been developed andproposed to the development projects for wideruse. Specif ic p roduc t ion and packagingtechniques for edible groundnut have beendeveloped and processing units installed andadapted to local product ion condit ions.

Selection

Previously, one or t w o great selection centersdealt w i th problems of varietal improvement forall the countries in the zone. Each country nowwants its o w n varietal creation unit. Manystates are pursuing work whose character isunfortunately sporadic: their means do not

remain constant, so research cannot be carriedon normally. This is most problematic whereselection work is concerned.

The IRHO has tackled the major problems,depending on the situat ion, and thanks to itsvaried arrangements, has tr ied to ensure theyare fo l lowed through.

D R O U G H T RESISTANCE. This p rogram was

started in Senegal, but due to the mult i localtests carried out in Mal i , Niger, Upper Volta etc.it took on a mult inat ional character. The f irstresistant variety, called 55-437 , f irst distr ibutedin the Louga area in 1962, now covers more than400 000 ha in the Sahel area.

Since then, great progress has been madeand the contr ibut ion to this problem has gonevery much beyond the Senegalese f ramework.At present, there are at least 10 usable resistantvarieties. Obviously, many other countriescould benefit f rom the advantage of this charac-teristic. A new mixed variety (edible and o i l ,known as 73-33) is thus being distr ibuted in thecentre of Senegal, and wi l l very likely cover vastareas in the future.

RESISTANCE TO ROSETTE. This was studied

more specifically in Upper Volta, but the use ofvarieties created f rom resistance genes isolatedin the Northern Ivory Coast has enabled theimprovement of very diverse groundnut types,including long cycle ones suitable for highrainfall areas, and short cycle ones suitable fordry zones or zones wi th t w o rainy seasons(Gabon, Congo, etc).

RESISTANCE TO ASPERGILLUS FLAVUS. This

is one of the themes studied by technologists,pathologists and breeders. Strains only sl ightlysusceptible have already been isolated, and inthe future, there wi l l be truly resistantgroundnuts. Similar work has just begun onrust resistance.

PRODUCTIVITY, SEED QUALITY , O I L CHEMICAL

C O M P O S I T I O N , ETC. These characteristics havebeen or are the subject of special selection onvarious stations where IRHO breeders work.

Crop Protection

Several methods are being examined, wi thspecial attent ion to the major pests likely to l imi t

27

groundnut y ie ld. There is a systematic study offungal diseases attacking seedlings using newformulae proposed by the phytosanitary pro-ducts ' manufacturers. Control techniquesagainst mil l ipedes are gradual ly being de-veloped and perfected.

Aflatoxin

It is by itself a vast p rogram, insofar as preven-t ion and detection are concerned. Developingtests enabl ing seeds' resistance to penetrationby the fungus, the use of sampl ing and sort ingtechniques are the result of a f irst series ofstudies, f rom wh ich numerous developmentsare expected in the near future.

Other diseases and parasites are beingstudied (rust, aphids, bugs, bruchids) but repre-sent only a small part of the IRHO's researchactivities.

Development and Extension Studies

One of our Institute's main concerns is apply ingresearch results. Research workers are only toooften satisfied w i th publ ishing their work, ci t ingthe results of fantastic experiments, w i thout itbeing possible to know whether they areappl icable to t radi t ional agriculture.

Thus, wherever possible, we have tr ied to getbeyond exper iment ing, and to make ful l sizetests of research results wi th the peasants.

In Senegal, on a network of several hundredha representing typical farms w i th groundnut ,grain and fa l low land rotat ion, we proved theprof i tabi l i ty of weak mineral manur ing chosenjudiciously as a result of leaf diagnosis over a 15-year per iod.

On an extension sector in Upper Volta, wewere able to demonstrate the value of Rosette-resistant varieties associated w i th s imple g row-ing techniques (sowing density, ferti l izer, etc.),thus reintroducing groundnut g rowing in anarea where it had practically ceased.

In Niger, Guinea Bissau, Mal i , etc, we set uppropagat ion units to develop new varieties andsupply growers w i th a sol id basis for apply ingmodern product ion techniques w i th guaran-teed profitabil i ty.

The IRHO is also present in integrated de-velopment projects to which i t contr ibutes aidand specialized knowledge of the groundnut . Itsintervention occurs either at the level of directpart icipation (as in Senegal for the ediblegroundnut operat ion, etc) or at the level ofoccasional technical advice (as in Mali to def inetechnical themes and the evolut ion of theirapplication) or even by bui ld ing industrial unitsfor product processing (SAN confect ionerygroundnuts).

The IRHO also participates in completestudies for restructuring the industry and pro-duct ion, as was the case in Gambia for thewhole groundnut sector, and in Senegal for thewhole edible and confectionery groundnutsector.

ConclusionCreated as a national body, the IRHO has be-come over the years an international associa-t ion, g iv ing developing countr ies specializedaid so that they can define, set up, and operateresearch programs, development projects orprocessing installations for tropical oil crops.

28

Appendix

List of countries where IRHO has been operat-ing for the last 15 years on a long-term basis(**), on a short- term basis at present (o), or as a consultant (*).

West Africa

(o) Benin:Castor research; consultancy for a develop-ment project (SONACO); yearly support fordirect ing agricultural research (groundnut,castor).

(**) Chad:Study of the part icipation in the integrateddevelopment project of southern Chad(groundnut, cotton); groundnut seed mul t ip-lication and experiments.

(*) Gambia:Study for restructuring the groundnut sectorincluding product ion and industrial ization.

(**) Senegal:Participation in ISRA's research work ongroundnut ; technical assistance for confec-t ionery groundnut product ion; technical as-sistance for the establ ishment and operat ionof a national seed service; study of theagroindustrial channels for confectionerygroundnut.

(*) Sierra Leone:Study of the possibil i t ies of the groundnutsection in the northern development project(IBRD).

(*) Togo:Study of the groundnut section of the de-velopment project in the mar i t ime zone(IBRD).

(**) Upper Volta:Scientific research on groundnut , sesame,soybean, and shea butter trees; researchstation marragement; seed mul t ip l icat ion;extension sector management.

(**) Guinea Bissau:Participation in scientific research and de-velopment activities for the Mancara Project;exper iments; seed mult ip l icat ion and otherstudies.

(»*) Ma l i :Scientific research on groundnut , sesame,and soybean; technical advice to OACV;technical assistance for groundnut seed mul -t ipl icat ion and storage; technical assistanceand services offered for the construct ion andoperat ion of a confectionery groundnut pro-cessing unit.

(**) Niger:Part ic ipat ion in scientif ic research ongroundnut and sesame; technical assistancefor organizing seed mult ip l icat ion operat ionsin Zinder, Maradi , and Dosso; periodic con-sultat ion for improv ing groundnut produc-t ion.

(*) Nigeria:Study of the possibi l i t ies of a cash crop(groundnut) rehabil i tat ion project in thenor th ; study of a groundnut seed mult ip l ica-t ion unit in the State of Kano.

Central Africa

(*) Cameroon:General oilseed crops study.

(o) People's Republic of the Congo-:Agricultural research on groundnut; seed mul-t ipl ication; consultancy for the development ofannual oilseed crops.

(o) Central African Republic:Agricultural research on annual oilseed cropsand study of a development project.

(o) Gabon:Agricultural research on groundnut; study of a development project in the plateau region.

East Africa

(*) Mozambique:Consultancy for the plantation societies andthe government.

Southern Africa

(*) Botswana:

29

Changes in the research and developmentrequirements of groundnut .

Central and South America

(*) Zambia :Technical support for p lanning a groundnutprocessing unit.

Indian Ocean

(*) Madagascar:Mission for assessing oilseed requirementsand the development p lan ; assistance to a castor project for genetic studies.

Far East

(*) Indonesia:Consultancy for improv ing castor product ion.

(*) Dominican Republic:Consultancy for groundnut development.

(*) Hait i :Consultancy for the development of annualoilseed crops.

(*) Mexico:Mission for ident i fy ing and studying the pos-sibil i t ies of groundnut and soybean projectson the east coast of Mexico for the PlanNacional Hydraul ico, and IBRD.

O c e a n i a

(**) New Hebrides:Groundnut research and experiments.

30

Peanut Collaborative Research SupportProgram Planning

C. R. Jackson and D. G. Cummins*

Our purpose at this Workshop is to in form youof the Peanut Collaborative Research Suppor tProgram Planning (CRSPP) effort. The col-laborative concept is a new USAID researchprogram in addit ion to other exist ing research,and is designed to aid research on a globalbasis. The planning is supported th rough a grant f rom USAID to the University of Georgia,made under provis ions of the Title XII programof the U.S. Board for International Food andAgricultural Development (BIFAD). The plan-ning office is located at the Georgia ExperimentStat ion, Experiment, Georgia, wh ich is veryf i t t ing since much of the modern peanut re-search or iginated at this station.

The planning grant was awarded on August12, effective August 1,1980 and wi l l extend overan 18 month period. Curtis R. Jackson, PlanningDirector, and David G. Cummins , AssociatePlanning Director, wi l l be responsible for ac-tivit ies under the grant. Robert Jackson, DS/AGR, is the AID Project Manager.

The Collaborative Research Suppor t Program(CRSP) concept is new to many of us. It is anarrangement wh ich facil itates long-term col-laborative research among U.S. universit ies,the U.S. Department of Agr icul ture, U.S. De-partment of Commerce, International Agr icul-tural Research Centers, other research institu-t ions, and developing country research insti-tut ions. Collaborative research embodies theidea of work ing jo int ly in a research endeavor.Funds and benefits f low pr imar i ly to the de-veloping countr ies, and the research is done inthe developing countr ies themselves, to themax imum extent practicable.

The pr imary goal of the CRSP is to develop a

* Planning Director, and Associate Planning Director,respectively, Peanut CRSP, Universi ty of Georgia,Georgia Exper iment Stat ion, Exper iment, Georgia30212, USA.

structure through which scientif ic talent andresources of the USA, not available in develop-ing countries, can come to bear on food produc-t ion , d istr ibut ion, storage, market ing, and con-sumpt ion problems in developing countries.The CRSP approach wi l l link inst i tut ions (andindividuals) having common interests in or-ganized research programs on selected prob-lems. The CRSP is bui l t upon exist ing researchprograms in developing countries. Developingcountry inst i tut ions wou ld part icipate out of a sense of pr ior i ty research needs and their capa-bil ity to contr ibute to a solut ion of the pr ior i tyresearch problems.

The CRSP is unique in prov id ing the l inkagebetween the U.S. and developing country in-st i tut ions, and in that the program must main-tain a university identity.

We, as the p lanning group, are interested incontact w i th interested individuals f rom thepeanut-producing countr ies around the wor ld .Our pr imary goals relative to developing coun-tries wi l l be to determine constraints to peanutproduct ion and uti l izat ion, assess interest inpart ic ipat ion in a CRSP, evaluate researchcapabil i ty and resources, and to improve ourknowledge of peanut research and product ion,and uti l ization.

Dur ing the fa l l and winter of 1980-81 , we wi l lbe involved in site visits and other activities todetermine country interests, develop the stateof the art in format ion, and identify constraintsto peanut product ion and uti l ization. In the earlysummer of 1981, preproposals wi l l be sol icitedf rom U.S. universit ies and other research in-st i tut ions to determine interest in col laborativeresearch programs to relieve these constraints.A selection process w i th the aid of a TechnicalPanel wi l l later result in ful l research proposals,establ ishment of U.S. and developing countryinsti tut ional l inkages, and f inal project de-velopment. The planning process is scheduledfor 18 months, concluding January 3 1 , 1982.

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A newsletter h ighl ight ing p lanning activit ieswi l l be publ ished periodical ly dur ing the courseof the project. Any inquir ies of interest in thenewsletter or anything else concerning theproject should be directed to Dr. Curtis R.

Jackson, Planning Director, or Dr. David G Cummins , Associate Planning Director, Univer-sity of Georgia, Georgia Experiment Stat ion,Experiment, Georgia 30212, USA, Telephone404-228-7312.

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Research and Extension Inputs Resultingin High Yields of Groundnuts in the USA

Ray O. Hammons*

The groundnut , Arachis hypogaea L., is animpor tant economic farm crop in the Uni tedStates. Ninety eight percent of the commercia lproduct ion is in seven states — two on themid-At lant ic coast, three in the Southeast, andt w o in the Southwest. Most of this area is a relatively humid zone al though some of theSouthwest crop is g rown under semi-arid fa rm-ing.

Groundnuts rank ninth in area among theUSA row crops and second in dol lar value perhectare. In 1979 the harvested crop area was617 400 ha, w i th a product ion of 1805 000metric tons (MT), averaging 2925 kg/ha.

Since the major thrust of this paper focuseson product ion inputs in Georgia, the leadinggroundnut state, the fo l low ing product ionstatistics show the current level of technologyachieved there. In 1979, Georgia farmers pro-duced 763 000 MT on 213 450 ha, for an averageof 3576 kg/ha. The crop value at the farm levelwas S360 000 000. In Georgia, groundnuts werethe No. 1 crop enterprise account ing for 12 .1%of the state's cash fa rm receipts.

This efficiency level can be attr ibuted totechnology developed by research and trans-ferred to the farmer by an effective agriculturalextension service. Since these major develop-ments occurred dur ing the past 25 -30 years, letme describe the situation then as a f rameworkagainst wh ich the product ion advances wi l lgain perspective.

Thirty years ago, the land was prepared w i ththe mo ld board p low and a spike tooth harrow,and seed was planted in a sl ight fu r row using a single row walk ing planter. The plants werecult ivated and hoed 3 or 4 t imes. Plant protec-

* Superv isory Research Genet ic ist and ResearchLeader — Crops, the Uni ted States Depar tment ofAgr i cu l tu re , Science and Educat ion A d m i n i s t r a -t i on , Agr icu l tura l Research, Southeast Area, at theUnivers i ty of Georgia Coastal Plain Sta t ion, T i f ton ,

Georgia 31793, USA.

t ion consisted pr imari ly of an application ofcopper-sulphate dust for leaf spot. A long-season cult ivar was g rown and harvesting wasusually begun when the leaves shed. Landpreparat ion, cultural practices, and the l i f t ingoperation were done w i th animal-drawnequipment. When the plants were lifted theywere stacked around a pole to f ield cure. After 6 weeks or more, the stacks were moved to a stat ionary mechanical picker where thegroundnuts were removed f rom the vines. Thissystem of product ion was labor intensive, re-quir ing about 185 hr/ha. Yields averaged under900 kg/ha (McGil l 1979).

Little research and extension effort wasapplied to the crop. Some cult ivar improve-ment, row and dri l l spacing studies, and thecopper-sulfur leaf spot fungic ide work formedthe technology informat ion bank. Neverthelessfarmers f rom six Southwestern Georgia coun-ties, meet ing in January 1950, attracted theattention of the state's leading newspaper bysett ing a goal of a "hal f ton per acre", or 1120kg/ha. As marginal land went out of product ionand growers began to try the new technology,the Georgia goal was reached in the 1956season.

Cultural practices in the middle 1950's werepoor by modern standards but were the bestthen known. Weeds were control led by p lowingas close as possible to the dr i l l , hoeing, anddir t ing to smother other weeds.

Many farmers grew established landrace cul-t ivars, w i th relatively low yielding potent ial , andkept their o w n seed or purchased it f r om a neighbor or a sheller-seedsman. In the latterinstance, Th i ram® (Arasan®) was usuallyapplied as a protective fungicide.

Adapt ive cultivars were developed mainly byline selection f rom farmers ' stocks or by screen-ing the l imited stocks of exotic introduct ions,al though the first series of cult ivars developedby selection fo l lowing hybridization were alsobecoming available. By 1960, farmers in the

33

Southeast had the choice of a number of cul -t ivars developed by public breeders in StateAgricul tural Experiment Stations and the U.SDepartment of Agr icul ture.

Since there were consumer products uti l izingthe major morpholog ica l groups of peanuts,growers had the opt ion of g row ing one or moreof the three USA market types and more thanone cult ivar of each type:

SPANISH . Small Spanish, Dixie Spanish, GFASpanish, Argent ine, Spantex, and Spanette.

RUNNER. Dixie Runner, Early Runner, FlorispanRunner, Southeastern Runner 56 -15 , and Vir-ginia Bunch 67.

V IRGINIA. Georgia 119-20 , Virginia Bunch G2,

Virginia Runner G26, NC 2, and Virginia 56R.Results of un i form variety tests, reorganized

after 1955 to prov ide comparat ive perfor-mances among cult ivars and advanced breed-ing lines wi th in market types, were widelypublicized. These data gave the farmer a ra-t ional choice of cult ivars to use in his fa rmingsystem.

The f ramework of cult ivars adapted to the soiland cl imatic features of the area provided a suitable backdrop for a number of break-throughs in g roundnuts research and develop-ment. It is not my purpose he re to provide a ful lchronology of these events since many of theachievements were interwoven together intothe product ion package.

The highl ights of research technology andextension inputs wh ich have led to high yieldlevels in the Southeastern United States may beout l ined as fo l lows:

Shaker-windrowerand Combine

The f i rst major advance was in equipmenttechnology. Groundnuts had emerged as a commercia l ly valuable crop w i th the develop-ment of the stationary picker in 1905 butal though horses, stat ionary engines, and even-tual ly tractors were used to power thesemachines, very l i tt le improvement in pickingefficiency had occurred in 40 odd years.

T w o pieces of equipment developed inthe late 1940's revolut ionized harvesting prac-tices. One was a shaker-windrower, wh ich

picked up the groundnuts after they were dug,shook out the soi l , and fo rmed t w o adjacentrows into a random w ind row for curing. Thisel iminated the stacking practice (Mil ls andSamples 1973). Then in 1948-50, J. L.Shepherd and W. D. Kinney developed a once-over mobi le peanut combine in research atTif ton. These two innovations, quickly adopted,cut the harvest labor requirement by about85%. They also led to the development ofartif icial dry ing principles used init ial ly at buy-ing stations, but soon adopted as an on-the-farm practice.

Tillage Methodsfor Disease Control

The second major advance was the developmentof ti l lage methods for nonchemical diseasecontrol. The practice of deep p lowing, fo l lowedby shallow, nondirt ing cult ivation, fo rmed thebasis of the suppression of the whi te mo ldcaused by Sclerotium rolfsii. L. W. Boyle andCO-workers (Boyle, 1958; Boyle and Hammons,1956) developed concepts, conf i rmed by a largebody of experimental evidence, on the benefitsof deep turn ing to bury surface organic matter.

Selective Herbicides

The th i rd major breakthrough came wi th thediscovery of selective herbicides for weed con-t ro l . L. W. Boyle, E. W. Hauser and associates atthe Georgia Agr icul tural Experiment Stationdeveloped a new scheme of cul ture throughresearch to lay the foundat ion for gains in yieldand crop quality and al lowed farmers to use thegenetic improvements bred into the newercultivars.

About 1959, Hauser led the pioneeringstudies showing that herbicide mixtures,applied at the g round cracking stage of seedl ingemergence, were more effective than the com-ponents of such mixtures. These results todaystil l fo rm an essential component of weedcontrol systems for groundnuts (and othercrops).

P r e c i s i o n L a n d P r e p a r a t i o n

The four th step was prov ided by J. L Shepherd

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i.e., engineer ing innovat ions in precision landp r e p a r a t i o n tac t i cs t o m a x i m i z e t h epathologic-agronomic practices and precisionplant ing to opt imize plant populat ions.

Organization of PeanutExtension Program

The Universi ty of Georgia established the posi-t ion of Extension Agronomist — Groundnuts,in the Cooperative Extension Service in 1959when J. Frank McGil l undertook this work. Thepathological , agronomic, and engineering prin-ciples described above were unif ied into a package approach for use. This package oftechnology, carried through the County Agricul-tural Agents, was quickly adopted.

Since 1959 the Extension Specialists team,located in the heart of the peanut belt at T i f ton,has increased to six: two in agronomy and oneeach in engineer ing, entomology, plant patho l -ogy, and weed control . The signif icance of thisteam lies not only in their skills in t ransmit t inguseful and t imely research informat ion directlyto farmers and/or through the County Agricul-tural Agents, but also in their funct ion to relaythe farmers ' needs and problems back to theresearchers.

Research/EducationPlanning Conferences

In the late 1950's the Universi ty of Georgia andcooperat ing USDA scientists organized a con-ference of workers engaged in groundnut re-search and education. This group has metannually w i t h administrators in p lanning ses-sions wh ich systematically identi f ied problemareas, discussed recent progress, and recom-mended new approaches and personnelrequirements. This conference prov ided an up-dating of key product ion constraints, a cross-fert i l ization of ideas, and an' oppor tuni ty forshift ing research responsibi l i t ies and resourcestoward solv ing new or dif f icult problems.

Growers Support Researchand Extension

A different kind of activity that has st imulatedgroundnut product ion in Georgia fo l lowed the

organization in 1961 of the Georgia Agr icul turalCommodi ty Commission for Peanuts (thePeanutCommission). This g rower g roup, usinga self assessment of $1 per ton since 1961 (and$2 more recently), has generously supportedgroundnut research at Georgia's three agricul-tural research facil it ies, has strengthened theextension specialist p rogram and has spon-sored graduate research fe l lowship grants. Thissupport equalled $2.5 mi l l ion f r om its ini t iat ionunti l June 1980 and is cont inuing. The Commis-sion regularly publishes a groundnut magazine,which is.circulated to all growers in Georgia,Florida, and Alabama (where more than 60% ofthe crop is grown). It provides a readily avail-able med ium for the rapid transfer of newtechnology to small scale farmers as wel l astheir more favored neighbors.

Effective Seed Dressings

Other signif icant research achievements camedur ing the 1960's. The development by C. R.Jackson and D. K. Bell of seed dressings usingorganomercurials significantly improved standsby virtual ly el iminat ing Aspergillus Crown Rot,the No. 1 seedling disease. After the removal ofthe mercurials by the Environmental ProtectionAgency, effective organic fungic ide com-binations developed by Bell have served as a reliable replacement.

Subsurface HerbicideIncorporation

In the early to mid-1960's Hauser developeddevices and methods for the subsurface incor-porat ion of the herbicide vernolate ®. The newsubsurface treatments enabled fanners to con-t ro l annual weeds and nutsedge more effec-t ive ly (and w i t h better crop tolerance)than wi th the previous methods of appli-cation.

Irrigation

The next major step came w i th the documenta-t ion by Engineers L. E. Samples and J. L.Stansell in 1965-68 of the magni tude of y ie ldand quali ty responses due to groundnut irr iga-t ion in the Southeast. In this area the sandy

35

soils, ro l l ing topography, f luctuat ing rainfal l ,and high cash value of the crop have led to theuse of sprinkler systems for g rowing irr igatedgroundnuts. Research and onfarm test datashowing a 1 0 - 1 8 % increased average y ie ld ,and frequent drought stress, led to a widespreadadopt ion of the new technology. From 7.5% ofthe Georgia g roundnut crop area irr igated in1970, the practice escalated to 23% by 1975, andto 48% in 1979. For 1980, a year of severedrought and heat stress, the est imate is 54%.

Variety Shifts

Al though a dozen groundnut cult ivars weregrown in Georgia in the late 1950's, two werepredominant . The Runner market type ac-counted for 55% of ail product ion area and DixieRunner alone for 34%. Spanish type occupied4 1 % of the area, w i t h Dixie Spanish on 24%.Virginia type accounted for less than 4 % .

The widespread availabil i ty of newer cul-t ivars wh ich responded wel l to the improvedtechnology inf luenced a marked shift by g row-ers. As the Argent ine and Starr cult ivars re-placed Dixie Spanish, Spanish-type product ionmoved to more than one-half the Georgia area.Even though the Early Runner cult ivar replacedDixie Runner, the total area in Runner typedecl ined to about 40% by 1969.

The start l ing change was the rapid rise inproduct ion of Virginia type groundnuts , wh ichmoved f r om 3% in 1959 to 14% in 1969. Thischange was inf luenced by a newly avai lablecultivar, Florigiant, and by a price structurefavor ing the larger seeded Virginia type.

The decade of the 1970's was a t ime for theintegrat ion of many research and extensioninputs result ing in h igh yields of groundnuts inthe Uni ted States.

Insect Scouts

In Georgia, entomological research by L. W.Morgan and associates about 1970 showed thatthe systematic use of insecticides el iminatedbeneficial insects, thereby increasing the totalpest problem and populat ion costs. As a directresult of th is research, an insect pest manage-ment p rogram was init iated in 1972 and theservice n o w includes almost one-f i f th of Geor-

gia's crop area. This program is based upon theprinciple that insects must be at economiclevels before control measures are just i f ied.That is, the loss in y ie ld or qual i ty at tr ibutable toinsect damage must exceed the cost of contro l .The program is voluntary by the growers andrequires trained insect scouts w h o regularlycheck f ields to moni to r insect levels. Growersadopt ing the program have greatly reduced thenumber of insecticide applications ( Informat ioncourtesy of L Morgan, H. Womack & R. Lynch).

Broadleaf Weed Control

Weed scientists in Georgia and Alabama coop-erated in showing that the groundnut planteffectively suppresses certain broadleaf weedspecies when the crop is mainta ined weedfreefor 5 - 6 weeks after they emerge. These results,combined w i t h subsequent r ow spacingstudies, increased the understanding of thecompet i t ive capacity of the peanut plant andenabled farmers to better plan their weed con-trol strategies for more efficient and moreeconomic product ion. More recent and currentresearch indicates that weed weights may bereduced by up to 50% and the y ie ld ofgroundnuts increased by 10% or more s implyby manipulat ing row spacing ( Informat ioncourtesy of E. W. Hauser and G. Buchanan).

The Florunner Cultivar

The most signif icant input of product ion re-search technology to high y ie ld performance inthe USA was the release of the Florunnergroundnut cult ivar in 1969 and its acceptanceby growers and the industry. Research anddevelopment of Florunner was conducted at theFlorida Agricul tural Experiment Stat ion and thebreeding methodology in use there wi l l bediscussed by A. J. Norden (this conference). Myconcern here is to describe some of the impactas other research inputs were meshed w i th theFlorunner cult ivar in the product ion package.

At the t ime of its release, Florunner had beenevaluated in cult ivar performance tr ials inFlorida, Georgia, and Alabama, where i tper formed wel l across a w ide range of soil andcl imat ic cond i t ions , exc lud ing p ro longeddrought.

36

Florunner is a product of a broadbased,open-ended breeding program that producesmul t i l ine g roundnut cult ivars w i th greatergenetic diversi ty than the pure l ine cult ivarsthey replaced (Norden 1980; Hammons 1976).At the t ime of its release, Florunner outyieldedits predecessor Early Runner by about 20%. By1979 it was g rown on 98% of the peanut croparea in the Southeast and occupied some 64%of the total crop area in the nat ion (Hammons,unpubl ished survey data).

O r g a n i c F u n g i c i d e s

Prior to 1970 almost ail of the groundnut far-mers used copper-sulfur dusts for control l ingleaf spots. With the discovery of the systemicfungicide benomyl (Benlate ® ) , and a protectivefungicide chlorothaloni l (Bravo ® ) , control ofleaf spot was significantly improved and yieldlosses f rom early defol iat ion were sharply re-duced. These organic fungic ides came on theheels of the introduct ion of Florunner and theiruse lengthened the f ru i t ing period by up to 2 weeks ( Informat ion courtesy of R. H. Littrell).The increasing use of i rr igat ion systems pro-vided addit ional water to support the extraproduct ion when natural rainfall was sparse.

F u n g i c i d e - t o l e r a n t S t r a i n s

The widespread and extensive use of benomylresulted in sel ection of strains of the Cercospora and Cercosporidium leaf spotting fungi that wasunparalleled in the use of fungicides for diseasecontrol . Research pathologists in Alabama andGeorgia almost s imultaneously discoveredstrains of these fungi tolerant (resistant) to thisotherwise highly effective fungicide. Tolerantstrains were found in 1973 using laboratorytechniques before economic losses occurredunder f ie ld condit ions.

In Georgia, R. H. Li t trel l , using laboratory andgreenhouse experiments, proved that benomyl-tolerant strains survived and were capable ofcausing disease. Based upon these results, thefungic ide was removed f r om the list recom-mended for 1974. Research data in 1974 indi-cated benomyl was completely ineffective, andyield in benomyl-treated plots d id not differf r om that in the untreated controls. Should

benomyl have been used in 1974, dramaticlosses f rom fol iar diseases w o u l d have occur-red (Littrell 1974 and personal communicat ion1980; Smi th and Littrell 1980).

A P a c k a g e A p p r o a c h

By the middle of the 1970's the original packageof product ion technology (McGil l and Samples1969) had been modi f ied (McGil l et al . 1973) toincorporate new discoveries. Further f ine-tun ing of the principles provides the f rameworkfor farmers in Georgia in the 1980's (Henning etal. 1979).

C u l t i v a r / l n s e c t i c i d e I n t e r a c t i o n

An addit ional input in the area of herbicideapplication is an example of fur ther research toopt imize the yield potential of the crop. E. W.Hauser led a three-state team that evaluated thegenetic vulnerabi l i ty of groundnuts to inten-sified pesticide treatments. They found that theyield of Florunner was signif icantly increasedmost of the t ime by the insecticide disulfotan (af ind ing wh ich surprised entomologists). An un-derstanding of these cultivar/insecticide in-teractions wi l l enable groundnut farmers tomore logically devise pesticide sequences foreffective pest contro l (personal communica-t ion , E. W. Hauser 1980).

F u n g i c i d e / N e m a t o c i d eC o m b i n a t i o n

In a simi lar manner, Pathologist S. S.Thompson led a team in demonstrat ing thebenefits of the soil fungic ide PCNB in combina-t ion w i th a nematocide (Mocap ® or Oasinit ®)in suppressing the wh i te mo ld fungus S. rolfsii.

Other major and minor advances in ag-ronomy, engineer ing, pathology, entomology,and other disciplines have contr ibuted substan-t ively to the product ion package. T ime wi l l notpermi t my discussing many of these. Amongthose wh ich may be listed are:

1. Improved agronomic practices, includingbalanced fert i l i ty of major and minor nu-tr ients appl ied fo l lowing soil test recom-mendat ions, precision l im ing , and the ex-

37

tensive use of gypsum (CaSC4) on Runnerand Virginia type peanuts.

2. W ind row inverters to shorten exposure ofthe dug crop to potent ial ly adverseweather and thus reduce losses in com-bin ing.

3. Avai labi l i ty and general use of effectivepesticides wh ich reduce mechanical con-tact w i th plants, provide season-long con-trol of insects and fol iar diseases, and givemoderate control of soi l -borne diseasesand nematodes.

4. Increasing use of some form of solid-setirr igat ion system to prov ide adequate soilmoisture upon demand.

5. Finally, and perhaps of greatest impor-tance, is the improved educational level offarmers w i th their greater awareness ofthe value and impact of agricultural re-search.

Farmers, now more than ever because ofsharply escalated costs, are w i l l ing to incorpo-rate effective and t imely research results intocommercia l product ion practices. This evolv inggrower att i tude has had a very posit ive effect onthe entire crop management program, part icu-larly in the southeastern peanut belt.

Actually, w i t h recent emphasis by the publicresearch sector on applied as contrasted w i thbasic research, and the rapid assimilat ion ofresults by growers, the stockpile of unusedtechnology is less extensive than it former lywas.

The examples of cooperat ive interactions be-tween researchers and their linkages wi th a mul t id isc ip l ine extension team as described inthis paper have shown that this approach isbetter than that of an individual alone t ry ing tosolve a myr iad of problems.

A c k n o w l e d g m e n t s

The author is indebted especially to J. FrankMcGil l for discussions on this subject since 1959and for sharing his unpubl ished notes. D. K.Bell, E. W. Hauser, R. H. Littrel l , and D. H. Smi thmade detailed responses, w i th examples, to a request for in format ion and gave permissionfor me to use their v iews. Appreciat ion is alsoexpressed to R. W. Gibbons w h o encouragedme to at tempt th is overv iew of technologyintegrated w i t h rapid appl icat ion by growers.

References

BOYLE, L. W. 1958. Fundamental concepts in the de-ve lopment of cont ro l measures fo r southern bl ightand root rot on peanuts. Plant Disease Reporter40: 661-665.

BOYLE, L. W., and H A M M O N S , R. O. Cultural Prac-t ices w i th respect to peanut yields and cont ro l ofsouthern bl ight and root rot. Universi ty of GeorgiaAgr icul ture Experiment Sta t ion.Mimeograph 3 1 . 12PP-

H A M M O N S , Ray O. 1976. Peanuts: Genetic vu lnerabi l -ity and breeding strategy. Crop Science 16: 5 2 7 -530.

H E N N I N G , R. J . , M C G I L L , J. E., SAMPLES , L. E., S W A N N ,

C , T H O M P S O N , S. S., and W O M A C K , H. 1979. Grow ing

peanuts in Georgia: A package approach. Coopera-t ive Extension Service, Universi ty of Gerogia Bulle-t in 640 (Revised). 48 pp.

LITTRELL, R. H. 1974. Tolerance in Cercospora arachidicola to benomy l and related fungic ides.Phytopathology 64: 1377-1378.

M C G I L L , J. FRANK. 1979. Forty years of pol icy impacton the fami ly peanut fa rm. Prepared at the requestof the (U.S.) Senate Agr icul tural Commit tee, Pages1-30, plus 8 appendix pages.

M C G I L L , J. F. 1980. Early 1950's research reshapedpeanut fa rming . Southeast Farm Press 7(13): 12.

M C G I L L , J. F. 1980. Phenomenal peanut y ie ld in-creases recorded in f irst half of 70's decade. South-east Farm Press 7(14): 12.

M C G I L L . J . F . , H E N N I N G , R . J . . S A M P L E S , L.E., FRENCH, J .

C, and T H O M P S O N , S. S. 1973. Growing peanuts inGeorgia: A package approach. Cooperat ive Exten-sion Service, Universi ty of Georgia Bul let in 640.(Revised). 48 pp.

M C G I L L , J . F., and SAMPLES. L. E. 1969. Growing

peanuts in Georgia — A package approach. Pages1-35 in Cooperat ive Extension Service, Univers i tyof Georgia Bullet in 640.

M ILLS, W. T., and SAMPLES, L. E. 1973. Harvest ing prac-t ices. Chapter 14, pages 4 9 5 - 5 0 8 , in P e a n u t s -cul ture and uses. Amer ican Peanut Research andEducation Associat ion.

N O R D E N , A. J . 1980. Crop improvement and geneticresources in g roundnuts . Pages 5 1 5 - 5 2 3 in A d -vances in Legume Science. R. J. Summer f ie ld and A.

38

H. Bunt ing , edi tors. Royal Botanical Gardens, Kew,Un i ted K i n g d o m .

S M I T H , D. H., and LITTRELL, R. H. 1980. Management of

peanut fol iar diseases w i th fungic ides. Plant Dis-ease 64: 3 5 6 - 3 6 1 .

39

Session 2 — Research Organizationand Development

Discussion

T. P. YadavaIn Haryana, wh i te g r u b has become an impor-tant insect pest and a check on groundnutdevelopment and spread. Do we have somemeasures to control this insect?

Vikram SinghD. R. C. Bakhetia has been looking for effectivelow cost insecticides, and the use of these asseed dressings.

D. R. C. BakhetiaFor wh i te g rub contro l in groundnut , seedtreatment w i t h insecticides has given veryencouraging results. Out of seven insecticidestested, seed t reatment w i th chlorpyr iphos 20EC, isofenphos 40 SD and carbofuran 50 WP at2.5 g a.i/kg seed gave an excellent control ofthe pest. The insecticides were also tested incombinat ion w i th th i ram (5 g/kg seed) to checkcollar rot incidence. Thus the control of whi tegrub, collar rot and both together helped inobta in ing 80 to 144, 104, and 130 to 196%increase in yield over contro l , respectivelyThese were tr ied at t w o locations over 2 years.

ChairmanThe costs of these seed t reatments is l o w rela-t ive to total product ion cos t

Vikram SinghThese treatments are not yet an official re-commendat ion , as they have not been testedby AICORPO.

R. W. GibbonsPlease, cou ld P. Gil l ier g ive details of seedmult ip l icat ion and cert i f icat ion schemes inf rancophone West Africa?

P. Gil l ierThe schemes are dif ferent in each country. InSenegal, there is a government seed service.Seed is g rown by farmers under cont rac t

Foundation seed is g rown by these farmersunder str ict ly control led condi t ions, w i thspecif ied seed dressings etc. It is then mul t ip -lied by cooperatives and then bought by theseed service for d ist r ibut ion. The seed serviceis a large organizat ion, w i th good control overthe seed and its pur i ty and germinat ion.

In Upper Volta, each farm er receives 10 to 20kg of seed and increases it himself for hissubsequent crops.

In Niger, seed is mult ip l ied by farmers undercontract.

R. W. GibbonsWhat are the problems of seed mul t ip l icat ionand dist r ibut ion in India?

Vikram SinghThe ini t iat ion of an efficient mult ip l icat ionsystem for breeders' seed is one of the short-term objectives of AICORPO, so we hope therewi l l be no further problems. Production offoundat ion and cert i f ied seed is beyond ourreach at present.

C. HarknessIn Nigeria, there are diff icult ies in gett ing largequantit ies of new seed. Wi l l the farmers g rowthe seed for mul t ip l icat ion of the new var i-eties?

Vikram SinghWe plan that the breeder wi l l mul t ip ly breed-ers' seed in the early generat ions, but aredebat ing what to do next w i th regard tofoundat ion seed. However, cert i f ied seed wil thave to be g rown on farmers ' f ields.

R. W. GibbonsI have been impressed in the USA by thenumber of extension workers w h o aregroundnut specialists. Which other countr ieshave appointed groundnut specialists to theirextension service?

40

K. S. LabanaIn the Punjab, India, we have extension work-ers w h o are oilseed specialists, based in theUniversit ies at Ludhiana and Kapurthaia. TheState Agr icul tural Department has extensionofficers too, not only in g roundnut but forother crops also. Most of these people arebreeders.

Vikram SinghExtension officers must be specialists in a particular discipl ine. We need workers w i th a thorough training especially in entomology,pathology, or agronomy.

G. D. PatilWhat are the causes of var iat ion in areas underdifferent g roundnut types in Georgia in diffe-rent years?

R. O. HammonsThe reasons are not related to soil type norfarmer preference. One is that there aresl ightly different price structures for differenttypes of groundnut , but the industry is alsoable to interchange end uses between diffe-rent types, and g row those types which givethe grower the max imum profit . Florunnergives high yield and greatest shell ing outturn,and so favors the grower, who is paid onshell ing out-turn. We grow for edible use, notfor oil extraction.

H. M. IshagIs shel l ing percentage solely control led bygenes, or is it control led also by agronomicpractices? In Sudan, we noted that in badlymanaged crops, we have high shel l ing percen-tage (it goes up to 70 to 72%) whi le in wel l -managed crops shel l ing percentage drops to62 to 65%.

R. 0. HammonsShell ing percentage is an inherent trait, but itdoes vary depending on the t ime in the grow-ing season at wh ich pod set occurs, and onotherfactors. In general , Florunner usually has75 to 77%, Florigiant 69 to 72%, and Spanishtypes in between.

H. M. IshagWhat is the reproduct ive efficiency of Florun-ner?

R. 0. HammonsWe do not know what the reproduct ive poten-tial of these varieties is.

U. R. Mur tyDoes the overproduct ion of f lowers ing r o u n d n u t rep resen t a n e v o l u t i o n a r ymechanism related to survival or does it alsorepresent a potential for increasing the pro-ductivity?

R. 0. HammonsWe have recovered 1400 seeds, plus 700 pegswhich had not matured at harvest, f r om a single plant. In the same trials we had morethan 1000 seeds on over 20 plants. Can wetransplant cutt ings, say of F1 hybr ids, andachieve improved yields?

H. T. StalkerCuttings of Fi hybr ids wi l l not produce asmany seeds as plants g rown f r om seedlings.The reproductive efficiency of most cutt ings ismuch lower than seedl ings; much of this isdue to fewer branches being produced onmost cutt ings. Also the cotyledonary lateralbranches usually produce most of the plant'sseeds, but cutt ings do not have these highlyproduct ive branch structures. The conclusionis that a f ield of F1 cutt ings probably wi l l notproduce as much per hectare as seedlings of a good variety.

J. S. ChohanWith the use of Benlate, was there an increasein the incidence of rust in the course of t ime? Ifso, how d id you face this problem?

R. O. HammonsRust is not a problem in USA except in Texas.

D. H. Smi thBenlate is not effective against rust. Rust issomet imes more severe when Cercospora leaf spots are control led by Benlate, becausethe compet i t ion w i th the leaf spots is el imi-nated.

Vikram SinghThe yield levels of 3500 kg/ha in Georgia areimpressive; much of this is due to g rowingFlorunner. Has the ful l y ie ld potential ofFlorunner been exploi ted, or is there stil l a gap

41

between exist ing yields and potential yield?

R. O. HammonsSome groundnuts are g rown on poor land notideally suited to them. Some of the yieldsobtained by the better farmers on good land(up to 7300 kg/ha) compare wel l w i th the bestyields on our exper imental plots (which arenot on the best land!).

S. H. PatilAccording to Dr. Vikram Singh of ICAR in India,about 8 years are required for a variety ofg roundnut before recommending i t for gen-eral cul t ivat ion. How many years of evaluationare required in the USA for similar recom-mendation?

R. 0. HammonsNormal ly 3 years of tr ials are needed beforethe state can recommend a new variety, but ifalready recommended in another state, only 2 years are necessary. We also test our breedinglines, so we have 3 to 5 years of test data. T w oorganizations are involved in release and pro-duct ion of seed. The Georgia Foundat ion SeedDevelopment Corporat ion takes the seed f r ompublic breeders and mult ip l ies it on state-owned farms in the foundat ion generat ion;that seed is then sold to farmers in the GeorgiaCrop Improvement Associat ion w h o mul t ip lythe seed under supervis ion, and the Agencycertif ies the seed.

S. M. Misar iI was impressed w i th the ever-increasingyields in groundnuts in the USA. In Nigeria atthe m o m e n t we have one extension worker to2000 to 3000 farmers. May I know h o w youhave gone abou tyour extension methodo logyand wha t is the present ratio of extensionworkers to farmers in the USA?

R. O. HammonsThe basis of the service is the s ix-man exten-sion team, and a County Agr icul tural Agent ineach county. There are about 75 extensionofficers for 16 000 farmers, or about 1 to every200 farmers.

K. S. LabanaIs there any micronutr ient p rob lem in USA? InPunjab we are fac ing micronutr ient problems

like deficiency of Zn, Fe, Mn , and Ca ingroundnut soils.

R. O. HammonsI can't provide details now, but wr i te to me andI w i l l send you the in format ion.

J. A. ThompsonWhat is the place of inoculat ion wi th rootnodule bacteria in the package deal for grow-ing groundnut in USA?

R. O. HammonsWe use a complete fertil izer, 400 lb/acre of5:10:15 or 4:12:12. Groundnuts usually fo l lowprevious groundnut crops, so less than 0 . 1 %of farmers use inocu lum; usually this is onland cropped to groundnut for the f i rst t ime.

B. S. GillDr. Hammons, you indicated that the areaunder Florunner increased rapidly in the 70s,and dur ing the same per iod the area of irr i-gated crop also increased. I wou ld like to knowthe relative contr ibut ion of the improved vari-ety and the irr igat ion.

R. O. HammonsThere is a 10 to 16% yield increase w i thi r r igat ion; there are variety responses to irri-gat ion and to excess i r r igat ion; some varietiesgive a 20% yield increase when irr igated.

N. D. DesaiDo you have areas under rainfed condit ions(wi thout irrigation)? Is there any product iontechnology developed for such areas or is anyvariety available?

R. O. HammonsI am sorry, we cannot offer you technology orreleased varieties. We have noted in varietytr ials that one of our lines, T i f t on 8', g rowsbetter and wi l ts later than other variet iesunder drought condi t ions, and we wi l l makeseed available if you request it. It does notrespond wel l under ample moisture, however.

P. S. ReddyNow that more than 50% of g roundnut inGeorgia is irr igated I presume that a lot ofin format ion migh t have been accumulated onirr igat ion studies. Can Dr. Hammons kindly

42

enlighten us on the fo l lowing?a. The critical stages of moisture stress for

dif ferent habit groups?b. Quantum of irr igat ion water required per

irrigation?

R. 0. HammonsThere is not an easy answer, as we get " i r r iga-t i o n " f r om frequent showers in addit ion to theirr igation water appl ied. The results f rom rain-out shelter studies are available and can bereferred to for details.

M. A. Al iDr. Hammons ment ioned that deep p lowinghas helped to control Sclerotium rolfsii. Wasthe control permanent or did the fungus be-come more serious when that particular pieceof land was deep p lowed again after 1 or 2 years?

M. K. BeuteDeep p lowing is a short- term control measure.Its effectiveness depends on when the debrisis brought back to the surface.

D. J. NevillHow wi l l Tit le XII interact w i th ICRISAT Pro-jects, and how wi l l ICRISAT feature in theplanning stage?

C. R. JacksonICRISAT wi l l be wr i t ten into projects whereapplicable. A lso Tit le XII wi l l not dupl icateon-going, wel l - funded projects.

J. S. SainiThere is a strong observation that groundnutsown for the f i rst t ime in a f ie ld gives goodyield under Punjab condit ions. But the samefield after 3 to 4 years of cont inuous groundnut

cult ivation shows a considerable decl ine inyie ld, even w i th the adopt ion of the sameproduct ion technology. Have you observedthis phenomenon in USA also, and wha t canbe the possible reasons for this decl ine undersuch a situation?

R. O. HammonsOur package includes intensive crop protec-t ion, so we do not have such problems.

ChairmanAny comments on monocropping?

N. D. DesaiIn Gujarat, groundnut is g rown year after yearand f rom generat ion to generat ion in the samefield. Not only that, but in the same fu r row — yet, there are no observat ions about declinein yield.

S. V. JaiswalGroundnut, when cult ivated for the f irst t imein the Punjab in a sandy f ie ld, wi l l y ield as h ighas 3 tonnes/ha. The farmers felt very muchencouraged and dur ing the second year, w i ththe application of the same inputs, the yieldcame d o w n to 1 Vi to 2 tonnes/ha. This suddendecline in yield dur ing the second year ofgroundnut cult ivat ion needs to be explained.This occurs especially in sandy soils.

J. S. ChohanThe explanation for the difference betweenthe sandy soils of the Punjab and the heaviersoils elsewhere is probably that in the sandysoils there are fewer microorganisms whichare antagonistic to the survival of the patho-gen in the soil between crops, so the secondand subsequent crops are exposed to higherlevels of inoculum than a crop in a f ield sownto groundnuts for the first t ime.

43

Session 3

Genet ics and Breeding

Chai rman: R. O. Hammons Rapporteurs: S. L. Dwived iR. W. GibbonsD. McDona ldS. N. N igam

Groundnut Genetic Resources at ICRISAT

V. R. Rao*

It is wel l known that the success of modern cropcultivars, the populat ion explosion and thedisturbance of the ecosystem have togethertended to reduce the genetic variabi l i ty in plantresources available to man. The grower, pro-cessor, d istr ibutor and consumer have de-manded uni formi ty in crop varieties and foodproducts. The plant breeder, to meet thesedemands, has reduced the genetic diversity inour major crop species and this has oftenresulted in their increased genetic vulnerabi l i ty.In a way, plant breeders have become v ict ims oftheir own success. Wi th diversity exist ing inlandraces being replaced by homogeneous im-proved cultivars, the danger of genetic ero-sion has become serious (USDA 1979). Ingroundnut , this process started as far back as1875 when Holle introduced into Java the Was-pada cult ivar, matur ing in 4 - 5 months, thatcompletely replaced native cult ivars matur ingin 8 - 9 months (Hammons 1973).

Wi th modernizat ion and urbanization, thenatural environs of w i ld and weedy specieshave been disturbed and some may becomeextinct. Natural habitat destruct ion, wh ich oc-curs only s lowly, can be seen happening todayin South America as far as Arachis species areconcerned. It is imperat ive that whatever gene-tic diversity remains should be assembled andconserved. This may be for immediate utiliza-t ion in crop improvement , or for future utiliza-t ion when the situation is expected to be evenmore alarming.

Arachis Genet ic Resources

Groundnut ranks 13th in importance among thewor ld food crops and is the most impor tantfood legume (Vamell and McCloud 1975). Com-pared to other oilseed crops and grain legumes,it is relatively daylength insensit ive and has a

* G r o u n d n u t G e r m p l a s m Bo tan i s t , Gene t i csources Uni t , ICRISAT.

Re-

high oil and protein content. As a crop it is wel ladapted and is readily accepted as a food.Groundnut is g rown on about 20 mi l l ion hec-tares, extending f rom tropical to temperatezones, in about 80 countries. The major produc-t ion zones are in the semi-arid tropics. Averageyields in the developed wor ld are about 2000kg/ha, but the wor ld average is less than 900kg/ha.

Arachis genetic resources include all the wi ldspecies and the cultivars under product ion. Thegenetic diversity in cultivated groundnut hasbeen cont inuously eroded in the groundnut-g rowing countries since crop improvementwork started in this crop. This process is veryclear in India and in some African countr ies,where improved cult ivars have been intro-duced, and the older landraces have almostcompletely disappeared. In some regions ofmany groundnut -growing countr ies, the pro-cess is s low and t imely collection now wou ldresult in conservation of such landraces. InSouth America, where Arachis or iginated,much valuable material exists. The develop-mental activities in many of the countr ies in thisregion wou ld soon result in the loss of thisvaluable germplasm (W. C. Gregory, personalcommunicat ion). Hence there is an urgent needto collect and conserve Arachis germplasmfrom these countries.

Some efforts to collect and conservegermplasm have been done in a few placesaround the wor ld in a f ragmented manner.Some of the major known Arachis collectionsare listed in Table 1. There is, undoubtedly, a certain amount of dupl icat ion in these collec-t ions. Table 2 lists the catalogs known f romvarious centers of conservation. From the list,one may take the vastness of the resources forgranted. Gregory et al. (1973) have warnedabout such a possible misconcept ion. Thesereserves are f ini te and exhaustible. Harlan(1976) has indicated the l imitat ions of our po-tential genetic resources in the l ight of thepossible genetic wipe out of the center of

47

T a b l e 1 . K n o w n sources o f g r o u n d n u t g e r m -p l a s m co l lec t ions .

Country Inst i tute/organization

USA a. Southern Regional Plant Introduc-t ion Stat ion (SRPIS), Exper iment ,Georgia

b. Nor th Carol ina State Univers i ty ,Raleigh

c. Univers i ty of Georgia, T i f tond. Univers i ty of Flor ida, Gainesvi l lee. Texas A & M Univers i ty , Stephen-

v i l lef. Ok lahoma State Univers i ty , Sti l l -

waterg. T idewater Research Center, Suf-

fo lk

Argent ina a. Univers i ty of the North-East, Cor-r ientes

b. Nat ional Inst i tute for Agr icu l tureand Technology (INTA), Cordoba

Brazil a. A g r o n o m y Inst i tute, Campinasb. CENARGEN/EMBRAPA, Brasil ia

Venezuela CENIAP, Maracay

Senegal,Upper VoltaIvory Coast,Niger etc.

a. Oils and Oilseed Research Inst i -tu te (IRHO), Paris, France

b. Senegalese Inst i tute of Agr icu l -tura l Research (ISRA), Bambey,Senegal

Niger ia Inst i tute of Agr icu l tura l Research,A h m a d u Bello Univers i ty (Samaruand Kano)

Malawi M i n i s t r y o f A g r i c u l t u r e andNatura l Resources (Chitedze Re-search Station)

S. Afr ica Depar tment of Agr icu l tura l Tech-nical Services, Potchefs t room.

Z imbabwe Crop Breeding Inst i tute, Sal isbury

Sudan Gezira Research Stat ion, W a d Me-dani

Israel a. Min is t ry of Agr icu l tu re , The Vol -cani Center, Bet-Dagon

b . The H e b r e w U n i v e r s i t y o fJe rusa lem, Rehovot

Japan Kochi Univers i ty , Kochi-ken

China Nat ional Academy of Agr icu l tura lSciences, Bei j ing

Indonesia Central Research Inst i tute fo r Ag-

r icu l ture, Bogor

Continued

T a b l e 1 . Continued

Country Inst i tute / Organizat ion

Austral ia Depar tment of Pr imary Industr ies,Kingaroy, Queensland

Malaysia Malaysian Agr icu l tura l Researchand Development Inst i tute

India a. Oilseeds Research Directorate,Hyderabad

b. A l l India Coord inated ResearchProject on Oilseeds (AICORPO)

T a b l e 2 . G r o u n d n u t c a t a l o g s a v a i l a b l e a tICRISAT.

Index Seminum Variet iesd'arachide (Arachishypogaea)

ISRA, CNRA,Bambey, Senegal

List of GroundnutGermp lasm,Potchefstroom

DATS, Republ icof S. Afr ica

Catalog of Seed Avai lab le atthe SRPIS, Georgia, USA

A R S - U S D A , USA

(1974 & 76)

Cult ivated Germplasm

Catalog-PeanutsNCSU, Raleigh,

USA

Germplasm Screened atDelh i , Ontar io , Canada

Universi ty ofGuelph, Gue lph,Canada

Groundnut Germplasm Bankin India

AICORPO (ICAR),India

Catalogo Anal i t ico dePoblaciones de Man i

INTA, Argent ina

Groundnut Seed Stored atNSSL

NSSL, Fort Col l ins,USA

Partial List of Groundnut

Avai lab le at CBI, Z imbabwe

CBI, Sal isbury,

Z i m b a b w e

Peanut Accessions NPGRL, Laguna,Phi l ippines

List of Int roduct ions

f r o m 01/61 to 08/76

The HebrewUnivers i ty ofJerusa lem,Rehovot, Israel

List of Arachis Germp lasm EMBRAPA-CENARGEN, Brazil

diversity and Hawkes (1979) clearly describedthe ways in which such a w ipe out may occur. Itis clear to everyone concerned that there is anurgent need to collect and conserve Arachis genetic resources i f we are, indeed, to cope w i ththe present and fu ture groundnut improvementproblems. Realizing th is urgency, ICRISAT hasbeen designated by the Consultat ive Group onInternational Agr icul tural Research (CGIAR) asa major repository for Arachis germplasm andhas been charged wi th the responsibi l i t ies ofgenetic resources activities.

Arachis G e n e t i c R e s o u r c e sa t I C R I S A T

The work in the groundnut improvement pro-gram was initiated at ICRISAT in 1976. Simul-taneously the genetic resource activities alsocommenced. The objectives are col lect ion,maintenance and evaluation of Arachis geneticresources and documentat ion and distr ibut ionof seed material and informat ion. During 1979,

the genetic resources work was reorganizedwi th the creation of the new Genetic ResourcesUnit wh ich took over the germplasm work in allf ive ICRISAT mandate crops. This did notchange the basic scope and objectives ofgroundnut germplasm work. Figure 1 showsthe basic activities of the Genetic ResourcesUnit.

C o l l e c t i o n a n d A s s e m b l y

Present S ta tus

Initially the major available resources wereidentif ied. Top prior i ty was given to acquir ingcollections available at var ious known centersfor ICRISAT. Al l the available collections f romvarious research institutes in India were do-nated to ICRISAT and about 5000 accessionshave been obtained in this manner (Table'3).This material , wh ich has been obtained w i th theexcellent cooperat ion of many inst i tut ions andin particular wi th the Indian Council of Agr icul -tural Research (ICAR), consists of many intro-

Figure 1. Genetic Resources Unit, ICRISAT — Operational flow chart.

49

COLLECTIONSFROM INDIA

DISCARDDUPLICATES REJUVENATION

REGISTRATION

SYSTEMATICEVALUATION

CLASSIFICATIONAND SEED INCREASE

LONG

COLD STORAGE

TERM

UTILIZATION

FOREIGN COLLECTIONSAND

INTRODUCTIONS

DOCUMENTATION DISTRIBUTION

duct ions, reselections f r om such introduct ions,

and experimental types developed w i th in India.

Similar ly about 3000 accessions have been

obtained f r om the USA, Japan, United King-

d o m , Senegal, Ma lawi , USSR, Nigeria, Z im-

babwe, South Afr ica and China (Table 4).

ICRISAT has initiated a contractual arrangement

w i th North Carolina State University, Raleigh,

USA for the supply of g roundnut germplasm

held at that center.

In addi t ion, ICRISAT has undertaken several

col lection expedit ions w i th in India and abroad,

and a total of 598 accessions have been ob-

tained so far (Tables 5 and 6). Generally random

sampl ing technique is used for col lect ion of

seed f rom farmers ' f ields and seed is collected

f rom as many plants as possible. Dur ing collec-

t i on tr ips, apa r t f rom collection of seed material ,

in format ion on cult ivat ion practices, locat ion,

pests and diseases is also collected. For th is

purpose, a germplasm collection data sheet has

been developed.

50

Tab le 3 . T rans fe rs f r o m Ind ian cen te rs .

Insti tute/ location Accessions

Andhra Pradesh Agr icu l tura lUnivers i ty, Kadir i & Kar imnagar 1364

Rajendra Agr icu l tura l Univers i ty,Ranchi 103

Mahatma Phule Krishi V idyapeeth,Jalgaon 263

G.B. Pant Universi ty ofAgr icu l ture and Technology,Pantnagar 11

Agr icu l tura l Research Stat ion,Durgapura 58

Al l India Coordinated ResearchProject on Oilseeds, T ind ivanamand Pollachi 681

Gujarat Agr icu l tura l Universi ty,Junagadh 1154

Oilseeds Experiment Stat ion,T ind ivanam 368

Punjab Agr icu l tura l Universi ty,Ludhiana 495

National Bureau of PlantGenetic Resources, Amravat i 159

Bhaba A tomic Research Center,Bombay 9

Punjabrao Krishi V idyapeeth, Akola 112

Regional Wheat Rust ResearchStat ion, Mahabaleswar 5

Tami l Nadu Agr icu l tura lUnivers i ty, Coimbatore 29

Others 67

Total 4969

Tab le 4 . Tans fers f r o m cen te rs a b r o a d .

Country Accessions

USA 2066Japan 74United K ingdom 20Malawi 263

Senegal 16USSR 3Z imbabwe 151South Afr ica 33Nigeria 103China 5

Total 2724

Tab le 5. Co l l ec t i on of loca l cu l t i va rs — Ind ia .

Mon th Year State Accessions

Mar/Apr 1976 Bihar, Orissa, andTami l Nadu 11

Nov/Dec 1976 Tami l Nadu, andAndhra Pradesh 23

Sept/Nov 1977 Rajasthan 7

Sept/Oct 1977 Karnataka (south) 35Oct/Nov 1977 Andhra Pradesh 92Apr 1978 Andhra Pradesh 4Oct 1978 Maharashtra 1Oct 1978 Karnataka (north) 151

Apr 1979 Andhra Pradesh 6Apr/May 1979 Karnataka (south)

and Andhra Pradesh 101May 1979 Maharashtra 1Aug/Sept 1979 Maharashtra

and Gujarat 19

Oct 1979 Uttar Pradesh 1

Table 6. Col lect ion of local cul t lvars -abroad.

Month Year Country Accessions

Mar/AprAprAprAug/SeptJune

19791979197919791980

BoliviaNepalMalawiSomaliaZambia

1213335

83

Up to mid-1980, about 8500 accessions hadbeen assembled and Table 7 gives the yearlyacquisit ion of this material . Table 8 presents theavailable germplasm, by country. Apart f r omthis, 1536 accessions f rom various countr ies arecurrently under quarant ine inspection (Table 9).

ICRISAT has a special interest in the wi ldspecies of Arachis for cytogenetic and resis-tance breeding work. Some species (Table 10)have already been obtained f rom the Tami lNadu Agr icul tural Universi ty, Coimbatore, In-d ia; North Carolina State University, USA; andReading University, U.K. and have been estab-lished at ICRISAT. The col lect ion f rom ReadingUniversity consists of material or iginal ly f romNorth Carolina State University, Raleigh;Oklahoma State University, St i l lwater; TexasA & M University, Stephenvi l le; ARS-USDA,Tif ton, Georgia, and the Division of Food Crops,Campinas, Brazil. More material is still beingtransferred. At the moment the w i ld speciesmaterial is maintained jo int ly by the GeneticResources Unit and Groundnut CytogeneticProgram.

Future Priorities

The IBPGR/ICRISAT ad hoc Commit tee onGroundnut Germplasm (September 1979) hasassigned the fo l low ing priori t ies for immediatecol lect ion:

South America Brazil, Argent ina, Peru,Bolivia, and Paraguay

Region Countries

South Asia BurmaSoutheast Asia IndonesiaMeso America Mexico, Central Amer ica,

and Caribbean Islands

West Afr ica Senegal, Nigeria,Upper Volta,and Gambia

East Afr ica Mozambique

Gregory et al. (1973) have described thedistr ibut ion of the genus Arachis in SouthAmerica, where more intensive collecting isnecessary to obtain valuable germplasm. Ef-forts are being made to launch expedit ions incol laborat ion wi th the IBPGR and CENARGEN/EMBRAPA (Brazil).

Quarantine

The importat ion of exotic groundnut material issubject to strict quarant ine regulations laiddown by the Government of India in order toprevent the entry of new pests or diseases intothe country. ICRISAT obtains the seed in thefo rm of shelled seed accompanied by regularphytosanitary certificates. The seed is plantedin plastic pots in the screen house at the CentralPlant Protection Training Institute (CPPTI),Rajendranagar. CPPTI has been authorized bythe Minist ry of Agr icul ture, Government ofIndia, to conduct quarantine work for ICRISATmandate crops. The seedlings remain underclose examinat ion for 6 weeks. Then thematerial is transferred, and transplanted, in thePost Entry Quarant ine Isolation Area (PEQIA)which is located in an isolated corner of theICRISAT fa rm. The seedlings are inspectedevery week by a jo int CPPTI-ICRISAT team andany plants showing suspicious symptoms areuprooted and destroyed. At matur i ty , the seedis harvested f rom the healthy plants and isreleased. These procedures al low an excellentwork ing relat ionship between the Genetic Re-sources Unit and the quarantine authorit ies.

For export, seeds f rom healthy plants arecollected. The seed is examined by the Indianquarant ine authorit ies and is then despatched

51

Table 7. Yearly acquisitions.

Year Accessions Total

1976 2443 24431977 3565 60081978 925 69331979 1216 81491980 349 8498(August)

52

T a b l e 8 . G r o u n d n u t g e r m p l a s m — s o u r c e coun t r i es ( A u g u s t 1 9 8 0 ) .

Country Accessions Country Accessions

AFRICA Brazil 243Ango la 2 Chile 12Dahomey 6 Ecuador 2

EgyptGambia

55

Paraguay 101

Ghana 6 Peru 62Uruguay 20

Guinea 2 Venezuela 8Ivory Coast 24 Others 114Kenya 28Liberia 10 813Libya 1

MadagascarMa law iMal iMaur i t iusMoroccoMozambique

865

975

10

ASIABurmaChinaCyprusIndiaIndonesia

16162

51715

25NigeriaSenegalSierra LeoneSouth Afr icaSudan

16785

742

674

IranIsraelJapanMalaysia

6314413

Tanzania 110 Phi l ippines 6

UgandaUpper Volta

ZaireZambiaZ i m b a b w eOthers

57101110

37784

Sri LankaTaiwan

Turkey

1720

3

2063

1827EUROPE

BulgariaGreece

24

Hol land 5N.C. AMERICA Spain 1

CubaCosta Rica

111 12

Honduras

Jamaica

3

1Mex ico 6 OCEANIA

Puerto Rico 19 Austral ia 45

USA 1240 Fiji 1

1281 46

SOUTH AMERICA USSR 49

Argent ina 195Bol iv ia 56 Unknown 1991

T a b l e 9 . Access ions unde r qua ran t i ne .

Country Accessions

Burma 5China 10

Indonesia 60

Italy 27

Malawi 6

Malaysia 56

Nepal 1

Senegal 341

South Afr ica 133

USA 814

Zambia 83

Total 1536

to the consignee w i th phytosanitary certif icateissued by the Government of India. This work iscarried out at thequarant ine laboratory situatedin the ICRISAT Center under the supervision ofCPPTI personnel.

tries, and genetic drift (Allard 1970). Goodstorage condit ions coupled w i t h proper grow-outs are expected to reduce the effects of suchproblems.

At ICRISAT all the cult ivated groundnut ac-cessions and seed producing wi ld species aremaintained by g rowing o u t In the case of thecult ivated groundnut , only pods attached to theplants are harvested. In the case of seed produc-ing w i ld species material , wh ich are considera-bly space planted, all the pods are collected. Therhizomatous and nonseed producing w i ldspecies are maintained in either brick chambersor concrete rings to prevent contaminat ion.Rejuvenation is carried out by root ing stemcuttings and rhizomes. As the long-term coldstorage facil it ies are still under construct ion,about one-third of the collection is plantedevery year for mult ipl icat ion and rejuvenationdur ing the postrainy season when there is lessincidence of pests and diseases.

Types of Collection

Though there is no recommendat ion regardingthe types of groundnut collections to be main-tained at ICRISAT, it is envisaged that thefo l lowing types wou ld be mainta ined:

ACCESSIONS COLLECTION. This includes all the

available groundnut accessions at ICRISAT. Itwi l l be maintained in long-term cold storage.

W O R K I N G C O L L E C T I O N . ( B A S I C C O L L E C T I O N )

This includes lines chosen and stratif iedby botanical variety, geographical distr ibu-t i on and ecological adaptat ion. This w o u l drepresent the genetic diversity available in thegroundnut germplasm.

W I L D SPECIES COLLECTION. This includes all the

wi ld species of Arachis wh ich have to be main-tained separately due to problems of handl ing.

Maintenance

The procedures fo l lowed in conservat ion,maintenance, and storage present many prob-lems. In mainta in ing the genetic puri ty of theconserved accessions, problems may arise dueto differential survival in storage, selection dur-ing rejuvenat ion, out-crossing w i th other en-

N A M E D CULTIVAR COLLECTION. All the cul-

t ivars named and released by publ ic and privateinsti tut ions wi l l be included in this collection.

GENETIC STOCK COLLECTION. This collection

includes all the sources of resistance to pestsand diseases, lines wi th specific desirable traitsand stocks w i th known genes.

53

Tab le 10 . Arachls spp at ICRISAT.

A. duranensis A. glabrata

A. batizocoi A. repens A. correntina A. sp (10038 LL & SL)

A. chacoense A. sp (C 565-66)A. cardenasii A. sp (C 9990, 9993,

10002)A. villosa A. sp (Man. 5)

A. stenosperma A. sp (Man. 8)

A. monticola A. sp (30008)

A. pusilla A. sp (30098)

A. paraguariensis A. sp (30093)A. villosulicarpa A. sp (30011)A. rigonii Many accessions ofA. hagenbeckii Rhizomatosae

Storage

At present the col lect ion is stored as unshel ledpods in air t ight containers in temporary storeswhich are not a i rcondi t ioned. The med ium-term cold storage facil i ty wh ich has been re-cently completed, w i th 4°C temperature and35% relative humid i ty , is now available forstor ing g roundnu t ge rm plasm. The long-termfacil i ty (- 18°C) has been approved for construc-t ion and should be completed by the end of1981.

E v a l u a t i o n a n d U t i l i z a t i o n

Collection, maintenance, and conservation havesignif icance in elucidat ing taxonomic statusand evolut ionary relat ionships between andwi th in the species. But the main justi f ication forgenetic resource conservat ion is for uti l izationin crop improvement . The key to successfuluti l ization of variabi l i ty f r om broad geneticpools requires the knowledge of desirable traitsavai lable in the germplasm. This requires a systematic evaluation of the germplasm. AtICRISAT, a mult id iscipl inary approach is fo l -

lowed and the available g roundnut col lection isevaluated by all the g roundnut scientists.

The prel iminary evaluation is carried out inthe PEQIA and dur ing the f irst g row out formult ip l icat ion. The mater ial is evaluated forabout 32 morphologica l and agronomic charac-ters. Promis ing material is then evaluated byother discipl ines. Table 11 gives some of thesources selected for resistance to pests anddiseases. These lines are being extensivelyused in the breeding p rogram to incorporateand improve the exist ing cult ivars. Lines iden-t i f ied elsewhere as early matur ing and highy ie ld ing, and which are in the ICRISAT collec-t ion are also being used in the respectivebreeding programs.

In the near future, germplasm wi l l also beevaluated for other useful attr ibutes such asdrought tolerance, high oi l content and sourcesof resistance to other pests and diseases. It isalso intended that in future, mul t i locat ion test-ing of some of the germplasm lines wi l l becarried out. At present, part of the ICRISATgroundnut germplasm is being evaluated inVertisols in Junagadh, Gujarat, in col laborat ionwi th National Research Center for Groundnut .

54

T a b l e 1 1 . P rom is i ng g r o u n d n u t g e r m p l a s m l i n e s .

Promis ing l ines

CharacterCult ivated(ICG Nos) Wi ld species

Leaf Spot(Cercospor id ium

personatum)

Rust

2716, 7013, 4747,6340, 6022

1697, 7013, 2716,4747, 6340, 6022,1703, 1705, 1704,1707, 1710, 6280,4746

PI 338280 (A. sp HLK-410),PI 338448 (A. pusilla),PI 276233 (A. sp 10596),PI 276235 (A. chacoense) A. chacoense x A. cardenasii, A. glabrata

PI 219823 (A. duranensis), PI 331194 (A. correntina), PI 262141 (A. cardenasii), PI 276235 (A. chacoense) A. chacoense x A. cardenasii Pl 338448 (A. pusilla),

PI 262848 (A. sp 9667),PI 276233 (A. sp 10596),A. villosa, A. villosulicarpa,

Continued

T a b l e 1 1 . Continued

Promising l ines

CharacterCult ivated(ICG Nos) Wi ld species

A. glabrata PI 298639 (A. batizocoi), PI 338280 (A. sp HLK-410)

Leaf Spot andRust

2716, 7013, 4747,6340

PI 338280 (A. sp HLK-410),PI 338448 (A. pusilla),PI 276233 (A. sp 10596),PI 276235 (A. chacoense), A. chacoense x A. cardenasii A. glabrata

Aflaroot rot 1326 Not tested

Collar rot 3263, 1326 Not tested

Aspergillusflavus

1326, 4749, 4750 Not tested

Pod rot 3336 ,3334 ,2951 ,1326, 1711,2031

Not tested

Tomato Spot tedWi l t Virus

1656,799 PI 262848 (A. sp 9667),PI 338448 A. pusilla),A. glabrata, PI 276233(A. sp 10596)

Peanut Mot t leVirus

2716, 4747 (Viruspresent in the p lantsbut does not go to theseed)

Not tested

C lump Virus 7677 ,5123 ,5118 ,8030, 3894, 6313,5210, 949

Not tested

Thr ips and

Jassids

5042, 5044, 5041

5043, 5045, 5040,2271

PI 276235 (A chacoense),PI 298639 (A batizocoi)

Aph ids Single plant selec-t ions f rom 5040

PI 276235 (A. chacoense),PI 298639 (A. batizocoi)

Termi tes 5045, 5929, 5040,5143, 2316, 1326

Not tested

Leaf miner 1697, 1703, 1704,5075, 2283, 2349

Not tested

Nodula t ion andBNF capacity

1561,2405,404 Not tested

55

Apart f rom this, the germplasm lines areevaluated systematical ly for yield and otherattr ibutes. Substant ia l amounts of suchgermplasm are being util ized in var ious breed-ing projects wh ich wou ld help to broaden thegenetic base of the material that goes out ofICRISAT. Some of t he earlier selections madef rom some accessions such as Robut 33-1 , havebeen suppl ied to the breeders and promis inglines have been selected f rom this mater ial .

Documentation

Progress in the f ie ld of plant genetic resourcesis related to the conservat ion of eroding geneticresources and uti l ization of this material forcrop improvement work. Success part ly de-pends on the availabi l i ty of in format ion on thematerial being conserved. W i t h the fo rma t i on ofinternat ional institutes, in format ion exchangehas assumed global importance, necessitatinga certain amount of un i formi ty in data collec-t ion , recording, storage, and retr ieval. The In-ternat ional Board for Plant Genetic Resources(IBPGR) is expected to play a key role in br ing ingan understanding among the workers in manycountr ies on these aspects and in the interna-t ional exchange of in format ion.

A c o m m o n descript ive language is impera-tive. At tempts to develop such a descript ivelanguage for g roundnut (genus Arachis) is un-der way, in close col laborat ion w i th IBPGR. TheIBPGR/ICRISAT ad hoc C o m m i t t e e onGroundnut Germplasm wh ich met dur ing Sep-tember 1979 appointed a subcommit tee tofinalize the descriptors for groundnut . The sub-commi t tee met dur ing July 1980 and hasevaluated a list of crit ically prepared descriptorsand a f inal draft for the approval of the membersis under preparat ion. This list contains 32 de-scriptors for passport in format ion and 40 de-scriptors of a morpho/agronomic nature. De-scriptors on disease and pest reaction are to beadded to th is list. After approval the descriptorswi l l be circulated among groundnut workersand then a f inal ized list w i l l be publ ished. A listo f the descr iptors used for g roundnu tgermplasm at ICRISAT is shown in Table 12.

Since the descript ive language is under prep-arat ion, t he data recorded dur ing the last f ewevaluations in ICRISAT site have not beenstored on the computer. However, these evalua-

Table 12. List of the descriptors used forgroundnut germplasm at ICRISAT.

Passport Data:1. ICG number2. Synonym number - 1 3. Synonym number - 2 4. Synonym number - 3 5. S y n o n y m number - 4

6. Sample type7. Col lector 's name and number8. Col lect ion date9. Sample source

10. Donor

11. Pedigree

12. Species, subspecies and var iety13. Cult ivar14. Pedigree15. Or ig in

16. Province/state and nearest v i l lage

17. A l t i tude, lat i tude, and long i tude18. Local name19. Soi l t ype20. Remarks

Morphological Data:1. Branching pattern2. G row th habi t3. Stem color4. Stem hair iness

5. Peg color6. Standard petal color7. Standard crescent8. Standard size9. Leaf color

10. Leaf shape11. Leaf size12. Pod type13. Pod beak14. Pod constr ic t ion15. Pod ret iculat ion

16. Pod length

17. Pod size18. Number of seed/pod19. Seed color20. Seed size2 1 . Seed shape

Agronomic Evaluation Data:1. Date of p lant ing2. Days to emergence3. Seedl ing v igo r4. Days to 50% f lower ing5. Plant height (cm)

Continued

56

T a b l e 1 2 . Continued

6. Plant w id th (cm)7. Total mature pods/p lant8. 100 seed we igh t (g)9. Yield (g/plot)

10. Date of harvest11. Days to matur i ty

tions, which used many of the proposed descrip-

tors, can be computer ized as soon as the de-

scriptors and descriptor states are f inalized. The

computer f i le fo rms the base for a l ive catalog

and only special lists wi l l be publ ished.

Distribution

The seed despatch to the scientists in India and

abroad is one of the important activities under-

taken by the Genetic Resource U n i t Table 13

gives the details of seed distr ibuted so far.

References

A L L A R D , R. W. 1970. Populat ion structure and sampl -ing methods . In Genetic resources in plants — thei rexplorat ion and conservat ion.

GREGORY, W. C. GREGORY, M. P., KRAPOVICKAS, A.,

S M I T H , B. W., and YARBROUGH, J . A., 1973. Structure

and genet ic resources of peanut. Pages 17-46 inPeanuts — culture and uses. Amer ican Peanut Re-search and Education Associat ion.

H A R L A N , J. R. 1976. Genetic resources in w i ld relativesof crops. Crop Science 16: 329-332 .

H A W K E S , J. G. 1979. Germplasm col lect ion, preserva-t ion and use. Presented at the Plant BreedingSympos ium- l l . 1 2 - 1 6 March 1979, Iowa State Uni-versity, Ames , Iowa, USA.

USDA (U. S. DEPARTMENT OFAGRICULTURE). 1979. Plantgenetic resources — conservat ion and use. Pre-pared by the Nat ional Plant Genetic ResourcesBoard. U. S. Government Pr int ing Office.

VARNELL, R. J . , A N D M C C L O U D , D. E. 1975. Pages 1-19

in Germplasm preservat ion and genotype evalua-t ion in Arachis. Internat ional Peanut Program,Gainesvi l le, Florida, USA.

57

T a b l e 1 3 . D i s t r i b u t i o n o f g r o u n d n u t g e r m -p l a s m .

Scientists in IndiaScientists abroadScientists in ICRISAT

538332624914

Breeding Methodology for Groundnuts

A. J. Norden*

The development of improved cult ivars is themajor responsibi l i ty of the plant breeder. Toaccompl ish th is the breeder must have f irst, a knowledge of the botany, genetics, and ecolo-gical requirements of the crop; second, establishsound breeding object ives; th i rd , collect orcreate a range of genetic var iabi l i ty ; and four th ,develop or devise the most sui table breedingmethod to fulf i l l the objectives. It is in theperformance of this last fundamenta l thatbreeders reach their best potent ial and ac-compl ish their most important role.

Before proceeding into a discussion ofg roundnut breeding methodology, however, I want to f irst emphasize the importance of thefirst three fundamenta ls to the groundnut im-provement process. The modern breeder isdependent to a large degree on the contr ibu-t ions and cooperat ion of researchers in manyother disciplines. T h e heart of a breeding pro-gram is the evaluation or screening of breedingmater ial , whether i t is to f ind the most suitableparents to use in a cross for a particular objec-t ive, or to isolate the superior progeny result ingf rom a cross. Groundnut breeders are depen-dent on pathologists, entomologists , chemists,engineers, physiologists, nutr i t ionists, etc., notonly for prov id ing basic knowledge on thesubject, but also for assistance w i th the de-ve lopment of suitable screening techniques.

Only l imi ted in format ion is available regard-ing the breeding behavior of groundnuts , thenature of inheritance, and the physiologicalimpl icat ions of impor tant characteristics. Ingroundnuts , where the end product is uti l izedpr imar i ly for human consumpt ion, addit ionaldata are required for reasonable certainty that

* A g r o n o m y Depar tment , Univers i ty of Flor ida,Gainesvi l le, Florida 32611, USA.

Note : Th is paper was prepared to supp lement in-fo rma t ion presented in sl ides at the Interna-t i o n a l W o r k s h o p o n G r o u n d n u t s , Oc tober1 3 - 1 7 , 1980 at ICRISAT, Hyderabad, India.

the new cult ivar wi l l excel, not only in y ie ld, butalso in processing and end-use product quality.

Determin ing the inherent processing, f lavor,and keeping qual i ty of groundnut lines is one ofthe more diff icult tasks facing breeders. Someof the older chemical tests are not completelyapplicable today, such as iodine value and fattyacid composi t ion. Taste and f lavor are affectedby the envi ronment and handl ing of the crop, aswel l as by the genotype. Processors and con-sumers have l itt le interest in y ie ld. Thus, someof the highest y ielding lines are not being g rowncommercia l ly today.

Breeding Objectives

The procedures involved in the development ofnew groundnut cult ivars opt imist ical ly spana period of 10 to 20 years. In v iew of thisand the changing trends in uti l ization and p ro -duct ion methods, establ ishing sound objec-t ives is extremely important in a breeding p ro -gram. The broad objective is to develop cultivarsthat are current ly in demand by the producer,the processor, and the consumer. It is impor tantto el iminate the defects wh ich hamper a cul-t ivar 's usefulness in a given region or per iod oft ime. It is only w i th in the past couple of yearsthat the energy requirements and/or contr ibu-t ions of g roundnut cult ivars in the fo rm ofnitrogen f ixat ion have become objectives ofimprovement programs.

Branch (1979) w i th the aid of several U.S.groundnut breeders recently compi led a list ofg roundnut breeding goals. For the grower theyinclude higher yields, more pest resistance, andmore env i ronmenta l stress-tolerance. Tosatisfy the processor, g roundnut breeders areat tempt ing to produce cult ivars wi th more uni-fo rm matur i ty and more favorable mechaniza-t ion and processing characteristics. The con-cern of the plant breeder for the consumerinvolves t ry ing to incorporate nutr i t ional seedpropert ies into cult ivars w i th f ru i t and seed of

58

preferred shape, size, texture, color, f lavor, andaroma.

Genetic Variability

It is a prerequisite to cult ivar improvement . Theprevious paper by Dr. V. R. Rao concernedgroundnut germplasm resources. Fortunately,there is a considerable amount of variabi l i tyavailable in the cult ivated species, especially inmorphologica l and chemical characteristics.The oil content of different genotypes variesf rom less than 40% to over 60% and the fattyacid composi t ion of the oil of di f ferent linesalso shows considerable variabil i ty. Somegroundnut lines have polyunsaturated to satu-rated oil ratios of almost 2 : 1 , the ratio consi-dered desirable for reduction of b lood serumcholesterol. Genetic variabi l i ty is also availablewi th in the species to increase some deficientamino acids, especially meth ionine, but morevariat ion is needed.

Mo re res is tance to cer ta in d iseases,nematodes, toxin-producing molds, and todrought is also required. Progress in cult ivardevelopment wi l l be enhanced as we improveour abil i ty to identify and incorporate the de-sired characteristics into improved cultivars. A better understanding of the cytogenetics ofArachis species is needed in order to deviseprocedures that wi l l enable the transfer ofdesirable traits f rom the w i ld species to becult ivated. This area is the subject of the nextSession on the program of this Workshop.

Groundnut BreedingMethodologyAn in-depth review of the l i terature ongroundnut breeding prior to 1972 was pub-lished in Peanuts — Culture and Uses (Norden1973) and a later review cover ing the per iod1972 to 1977 in Advances in Legume Science (Norden 1980). As I had emphasized in the latterpaper, " n e w and spectacular discoveries inplant breeding methodology, not only ingroundnuts buta lso in other crops, are rare, andthat there had not been any major advances ingroundnut breeding methods dur ing the f iveyears 1972 to 1977."

The breeding methods by wh ich new cul-t ivars of groundnuts or ig inate are not unl ike the

methods used for many other self-poll inatedcrops. They are: (1) introduct ion and select ion;and (2) hybr id izat ion or recombinat ion .Backcrosses, mul t ip le crosses and recurrentselection all utilize hybridizat ion. In irradiat ionbreeding, x-rays or other radiat ion is used toobtain mutant plants that may be helpful in thedevelopment of improved cultivars.

Introduction and SelectionIn the early part of this century the objectives ofgroundnut improvement programs could bemet by l ine selection f rom or direct use ofcultivars f rom other countries. Whi le thismethod is still satisfactory in some cases, suchas the selection of Makulu Red f r om the Bolivianstrain of groundnuts, Mani Pintar (Smartt 1978),it is inadequate in fu l f i l l ing most of the objec-tives of many breeding programs.

Because of the large investment in equip-ment, facil i t ies, maintenance, and manpowerrequired in ful l scale breeding programs, theneed for cooperat ion between countries orterr i tories is important. The groundnut im-provement program at ICRISAT, which is thesubject of the next paper, was designed w i ththis in m ind .

Hybr id izat ion or Recombinat ion

Hybridization and selection among and wi th inhybrid lines is currently the most w ide ly usedmethod of obtain ing improved groundnut cul-t ivars. Success in breeding hybridization de-pends on the availabil i ty of transferable geneticvariat ion and wil l more likely occur if the objec-tives are clearly designated, the correct parentsare selected, and if the hybrid populat ions aremanaged properly and selected successfully.Generally, the better and more adapted parentsgive better segregates or at least increase thel ikel ihood for product ion of desirable new re-combinat ions. In any regard, at least one parentin a cross should be a reasonably good per-former in the product ion area to be considered.The rare but greatly superior segregate, how-ever, is more likely obtained f rom crosses be-tween plants wi th more diverse genotypes.

The general procedure tor handl ing segregat-ing hybr id populat ions for a self-pol l inatingcrop such as groundnut usually involves theuseof the bulk o r t h e pedigree system or numerous

59

modif icat ions of the two . Experimental evi-dence concerning the meri ts of using one of thesystems to the exclusion of the other for breed-ing self-pol l inat ing crops is contradictory. Ingroundnut breeding, no reports of comparisonswere found and both methods are somet imesused by the same breeder.

The pressure to produce new cult ivars wh ichhave pest resistance and other economical lyimportant traits has forced some breeders tomodi fy their breeding systems in o rder to speedup cult ivar development. One such method is a modi f ied pedigree method of selection usingsingle seed descent, wh ich was successfullyused at North Carolina (Wynne 1976).

Breeding Techniquesfor Specific Objectives

Higher Yield

By necessity, much of the emphasis ingroundnut breeding throughout the wor ld isplaced on improv ing y ie ld. This is partly inresponse to the increased food requirementscaused by an increasing populat ion and l imi tedland resources and part ly due to the everincreasing costs of product ion. Producinghigher yields per unit area is one of the waysthat the grower has to counteract the costs ofproduct ion.

The general procedures employed in breed-ing for higher yields fo l lowing the hybridizat ionmethod were reviewed by Norden (1973). Garet(1976) reported the response of eight charactersf rom a dial lel cross of f ive cult ivars. He obtainedheterosis compared w i th the better parent forseveral y ield components. General and specificcombin ing abil i ty effects and reciprocal effectswere signif icant fo r all characters except oilcontent, where general comb in ing abi l i ty ef-fects alone were signif icant. Addi t ive effectspredominated for all characters except seedy ie ld , where nonaddi t ive effects w i th d o m i -nance and epistasis were observed.

Stabil i ty in product ion over seasons and overa w ide area is an impor tant attr ibute of a commerc ia l g roundnut cult ivar. An object ive ofthe Florida groundnut breeding program is tomo ld the cult ivar to f i t the somewhat specificand restr ict ive U.S. market ing system, wh i le atthe same t ime making a conscious effort toavoid deplet ing the cult ivar of its genetic

versatility through composit ing lines in earlygenerations. Pressures for monocultural produc-t ion and uni formi ty exist throughout the chainf rom farmer to customer. Hammons (1976)reported that the al loploid genetic structure ofA. hypogaea and modi f ied breeding proceduresprovide greater genotypic diversity for theeconomical ly dominant cult ivars in the UnitedStates than that exist ing in the pure l ine cul-t ivars they replaced. He caut ioned, however,that further w iden ing of the genetic base mayrequire changes in cult ivar seed cert i f icationstandards and market-grading criteria in theUnited States.

Pest Resistance

There have been recent advances in g roundnutbreeding for resistance to pests but many com-plex prob lems still remain. For example, goodresistance to some pests has been found only inthe w i ld species, but these sources ofgermplasm have been largely unavai lable be-cause of certain inherent barriers to hybridiza-t ion (Banks 1977; S impson et al . 1975).

Thel i teratures ince 1972 concerning breedingfor pest resistance in groundnut is very exten-sive, and since groundnut pests and pest resis-tance are the subjects scheduled for the Work-shop tomor row I wi l l curtail this por t ion of mypresentation and i l lustrate w i th slides thegroundnut breeding methods we are currentlyusing in Florida.

Conclusion

The groundnut improvement project in Floridainvolves control led hybridizat ion fo l lowed bypedigreed select ion w i th in and betweenthousands of di f ferent lines. Most peanut cros-ses do not result in improved cult ivars. Thebasic procedure is to discard the undesirableplants and lines early in the breeding programand save only those w i th apparent superior i ty ineconomical ly desirable characteristics. It is di f-f icult to incorporate desirable characteristicsinto a variety w i thou t being overwhe lmed byundesirable mater ial . Often the desirablecharacteristic is associated w i t h undesirabletraits.

A l though the groundnut is di f f icult to hy-bridize, mak ing the cross is the least t ime con-

60

suming phase of the breeding program. The

basic technique for crossing groundnuts has

not been greatly changed over the years, but

numerous aids and modi f icat ions have been

reported (Norden 1980).

References

BRANCH, W. D. 1979. Peanut Farmer 15(4): 9.

B A N K S , D .J . 1977. Pages 406 in 1977 Caddo ResearchStat ion Report. Ok lahoma Agr icu l tura l ResearchStat ion, St i l lwater, Oklahoma, USA.

GARET, B. 1976. Oleagineux 3 1 : 435.

H A M M O N S , R. O. 1976. Crop Science 16: 527.

N O R D E N , A. J. 1973. Pages 175-208 in Peanuts-cul ture

and uses. C. T. Wi l son , ed. Amer ican PeanutResearch and Education Associat ion, St i l lwater, Ok-lahoma.

NORDEN, A. J. 1980. Pages 515 -523 in Advances inlegume science. R. J. Summer f ie ld and A. H. Bunt-ing , eds. Royal Botanic Gardens, Kew, England

N O R D E N , A. J. 1980. Pages 443-456//7 Hybr idizat ion ofcrop plants. W. R. Fehr and H. H. Hadley, eds.Amer ican Society of Ag ronomy , 677 S. Segoe Road,Mad ison , Wiscons in , 53711.

S I M P S O N , C. E., S M I T H , O. D., and HARRISON, A. L. 1975.

Pages 6 - 9 in Peanut Product ion in Texas. TexasAgr icul tura l Experiment Stat ion, College Stat ion,Texas, USA.

S M A R T T , J. 1978. Euphytica 27: 605.

W Y N N E , J. C. 1976. Proceedings of the Amer icanPeanut Research and Education Associat ion 8: 44.

61

Groundnut Breeding at ICRISAT

S. N. Nigam, S. L. Dwivedi, and R. W. Gibbons*

Breeding work on groundnuts started in m id -1976 after the acceptance of the detailed re-search proposal (Gibbons 1976) by the Govern-ing Board of ICRISAT.

The main object ive of the program is toproduce h igh y ie ld ing breeding lines or popul a-t ions w i th resistance to the main factors pre-sently l imi t ing product ion.

Much emphasis has been laid on diseaseresistance breeding — particularly for diseasessuch as leaf spots (Cercospora arachidicola andCercosporidium personation) and rust (Puc-cinia arachidis), wh ich are of international im-portance. Other prior i t ies include breeding forearliness, high yield and quality. Since 1976,several more research projects have beenstarted as and when necessary germplasmbecame available.

Groundnut g row ing env i ronments varygreatly not only between but also w i th in coun-tries. In addi t ion, there is considerable diversityin the uses to which the crop is put. Consideringthe diverse requirements, emphasis has beenon supply ing suitable early generat ion andadvanced breeding material to cooperators indifferent countr ies of the Semi-Arid Tropics(SAT) for fur ther selection in si tu.

Program and Progress

Hybridization

The emasculat ion and pol l inat ion processesused at ICRISAT are basically the same as thosedescribed for Florida by Norden (1973). How-ever at Hyderabad, emasculat ions can be madeas early as 1.30 p.m compared w i th 5.00 p.m inFlorida. Pol l inations are carried f rom 7.00 a.m to10.00 a.m in Florida, but the highest successrates are achieved at Hyderabad if they aremade around 6.00 a.m.

* Plant Breeders and Principal Plant Breeder,Groundnu t Improvement Program, ICRISAT.

The standard method of making crosses is touse large pots, containing single parentalplants, wh ich are placed on benches inside a glasshouse or screenhouse. However, i t wasrealized that for the large numbers of crosses,wh ich needed to be made for an internationalbreeding program, there were severe l imita-t ions in using th is method. In 1977 crossing wastherefore extended to the f ield. Initial resultswere poor, but by improv ing insect control andusing an irr igation system to maintain highhumid i ty at the t ime of pol l inat ion, successrates of over 50% were obtained in therainy season of 1979 and the postrainy seasonof 1979-80. During the current rainy season of1980 the success rate averaged 67%, w i thsome individuals achieving as high as 94%.During each of the two crop seasons some30 000 pol l inat ions are made in the f ield. Aslarge number of crosses can now be carried out,specific combinat ions could be made for breed-ers in national programs w h o have l imi tedfacilit ies.

Initially the hybridizat ion program mainlyutil ized germplasm lines but now after fouryears lines der ived at ICRISAT are being used asparents to combine more desirable charactersin breeding populat ions.

Rapid Generation AdvanceThe cl imatic condi t ions and the facil it ies at theICRISAT Center provide opportuni t ies to g rowt w o ful l crops in a year. Many of the majorpathogens and insect pests either occur, or canbe induced, dur ing both seasons and thusprovide good opportuni t ies for cont inuous sc-reening.

The problem of postharvest dormancy inVirginia types (sub sp hypogaea) prevent ingimmediate replant ing in the second crop sea-son, has been overcome. The seed is dressedwi th Ethephon, an exper imental preparat ion inpowder f o rm of an ethylene-releasing com-

62

pound (Amchem Products Ina , USA), beforeplant ing. In the laboratory more than 90% oftreated seeds germinate wi th in 24 hours. Usingthis technique under f ield condit ions, 7 5 - 8 0 %emergence is obtained w i th in a few days.

Evaluat ion

The advanced breeding populat ions areevaluated in two different envi ronments at theICRISAT Center. The rainfed crop is g rownunder low ferti l ity condit ions (20 kg P2O5) and isnot protected against diseases and insect pests.The irr igated crop is g rown at higher fert i l i tylevels (40 kg P2O5) and is protected. Early gener-ation segregating material , when enough seedis available, is also g rown in both environ-ments. Very l i tt le material is discarded in earlygenerations. Most of the material is bulked intouni form groups for evaluation and furtherselection at cooperat ing centers.

Stabil i ty of y ield is important overyears andacross sites. Currently the breeding material isevaluated on a l imi ted scale in different agro-cl imatic zones in India. An international test ingnetwork wi l l soon be set up after the establish-ment of outreach programs.

Research Pro jects

Breeding for Resistanceto Foliar Pathogens

At present the work on foliar diseases atICRISAT is restricted to rust and Cercospora leaf spots as they are wor ldwide in distr ibution

and cause serious economic losses (Bunt ing etal. 1974; Hammons 1977; Subrahmanyam et al.1979).

SOURCES OF RESISTANCE. Rust resistance

breeding started in 1977 w i th t w o sources ofresistance, PI 259747 and PI 298115. Since thenseveral other sources of resistance have alsobeen incorporated in the breeding program(Table 1).

High levels of resistance to leaf spots occurwi th in the w i ld species (Abdou 1966; Abdou etal. 1974). Leaf spot resistant tetraploid pro-genies, resulting f rom interspecific hybridiza-t ion , wi l l soon become available f rom theCytogenetics subprogram for utilization by thebreeders (see Singh et al. in this volume).

Recently more intensive searches w i th in thecult ivated groundnut have shown some us-able sources of resistance or tolerance toleaf spot fungi (Sowell et al. 1976; Hassan andBeute 1977; Melouk and Banks 1978; Sub-rahmanyam et al. 1980b). Many of thegermplasm lines earlier selected for rust resis-tance have also shown resistance to lateleaf spot at the ICRISAT Center (Table 2). Sev-eral rust-resistant FESR selections made atICRISAT are also resistant to late leaf spot (Table3). A few rosette-resistant cult ivars, such asRMP 91 and RMP 12, have also some resistanceto late leaf spot (Subrahmanyam et al. 1980b).For resistance to early leaf spot, NC 3033 (Beuteet al. 1976) and P1109839 (Hammons et al . 1980)are being util ized in the breeding program.

CURRENT STATUS. The breeding material for

rust resistance, other than FESR selections, has

Tab le 1 . Sources o f rust res is tance.

Cult ivar Source Type Reference

PI 259747 Peru Valencia Mazzani and Hinojosa 1961

PI 298115 Int roduct ion to Virg in ia Hammons 1977

Israel f r om USA Bunch

NC Acc 17090 Peru Valencia Subrahmanyam et al. 1980a

EC 76446 (292) Uganda Valencia Subrahmanyam et al. 1980a

N C A c c 17133 (RF) S. Amer ica Valencia Subrahmanyam et al. 1980b

DHT 200 Peru Valencia Hammons 1977

FESR select ions USDA rust Variable Bailey et al . 1973;

nursery, Subrahmanyam et al.

Puerto Rico (unpubl ished data)

63

T a b l e 2 . Rus t res is tant sources a lso res is tan t t o l a ta loaf spot .

Cultivar Source Type Reference

PI 259747 Peru Valencia Filho and de Moraes 1977;

Subrahmanyam et al. 1980bEC 76446 (292) Uganda Valencia Subrahmanyam et al. 1980b

NC Acc 17133 (RF) S. Amer ica Valencia Subrahmanyam et al. 1980bFESR select ions USDA rust Variable Subrahmanyam et al.

nursery,

Puerto Rico

(unpubl ished data)

T a b l e 3 . Rust and la te leaf spo t reac t ions o fs o m a FESR se lec t ions in f ie ld sc reen-ing t r ia l s a t ICR ISAT Cen te r , 1 9 7 8 -

1 9 8 0 .

Mean disease scorea

Select ion Rust Leaf spot

FESR 5-P2-B1 2.0 3.0

FESR 5-P17-B1 2.0 3.0

FESR 7-P13-B1 2.0 3.0

FESR 9-P3-B1 2.0 3.0

FESR 9-P4-B1 2.0 4.3

FESR 9-P7-B1 2.7 3.3

FESR 9-P7-B2 2.7 4.3

FESR 9-P8-B2 2.0 3.0

FESR 9-P12-B1 2.0 2.7

FESR 11-P11-B2 2.3 2.7

FESR 12-P4-B1 2.0 2.0

FESR 12-P5-B1 2.0 2.7

FESR 12-P6-B1 2.7 3.7

FESR 12-P14-B1 2.0 3.3

FESR 13-P12-B1 2.0 2.7

TMV-2 (Check) 9.0 9.0

a. Mean score of th ree seasons on a 1-9 scale.whe re 1 - no disease and 9 = 50-100% fo l iage des t royed.

been advanced to the F6 generat ion generallyby fo l low ing pedigree and bulk pedigreemethods. Backcrossing has been adoptedin a few cases. The material is screened inthe f ield for both rust and leaf spot resistanceusing the infector-row technique developed bySubrahmanyam et al. (1980a). The plants arebroadly classified into resistant and susceptiblegroups based on f ie ld scoring using a 1 -9 scale(where 1 = n o disease, and 9 = 5 0 - 1 0 0 % defo-liation). Single plants or bulks classified as h ighyield ing but susceptible to fol iar pathogens are

retained for further screening and use in otherbreeding projects.

FESR SELECTIONS. Fourteen F3-derived rust-resistant lines (FESR 1-14), f rom a natural crossbetween PI 298115 and an unknown pol lendonor in the USDA rust nursery in Puerto Ricowere received at ICRISAT in 1977 (Bailey et al.1973). These l ines segregated not only fo rmorphological characters but also for reactionto rust at ICRISAT Center. All the lines wereprogeny-rowed in the next generat ion whenthey again segregated for reaction to rust. Thisindicated that resistance to rust, though reces-sive, may not be governed by duplicate loci ashas been reported by Bromfield and Bailey(1972). Since then the material has been ad-vanced to the F8 generation. Fifteen hundredand forty-six selections are currently beingfinally assessed in the f ield for yield and rustresistance.

Some of the resistant FESR selections,evaluated under rainfed and low-ferti l i ty condi-t ions, have yielded more than the releasedIndian cultivars, J-11 and Robut 33-1, and therust-resistant parent, NC Acc 17090 (Table 4).

Breeding for Earliness

Groundnuts, wh ich are earlier matur ing thancurrently released cultivars and possess highyield potent ial together wi th good qual i ty, wi l lbe extremely useful in areas of the SAT wh ichhave short g rowing seasons or where an earlymatur ing crop may escape certain pests anddiseases. There is also scope for f i t t ing earlymatur ing groundnuts into relay or sequentialcropping systems, particularly in SoutheastAsia by uti l izing residual moisture after theharvest of the rice crop (Gibbons 1980).

64

Tab le 4 . P e r f o r m a n c e o f FESR se lect ionsunder low- fe r t i l i t y and ra in fed condi -t i ons ( ra iny seeson 1 9 7 9 ) .

Yield

Select ions (kg/ha)

FESR 8-P12-B1-B1-B1 1301

FESR 5-P20-B1-B2-B1 1127

FESR 9-P5-B1-B1-B1 1076

FESR 8-P9-B1-B1-B1 1076FESR 8-P11-B1-B2-B1 1003

FESR 8-P13-B1-B2-B1 1001FESR 5-P19-B1-B2-B1 996FESR 8-P3-B1-B2-B1 987NC Acc 17090a 978Robut 3 3 - 1 * 816J 11b

524

LSD (0.05) 282.7

a. Rust-resistant check.b. Suscept ib le checks.

Tab le 5 . Early ma tu r i ng se lec t ions (pos t ra inyseason 1979—80) .

F4 generat ion F5 generation

Argent ine x Chico JH 89 x Chico2-5 x Chico JH 171 x Chico28-206 x Chico Dh 3-20 x ChicoSM 5 x Robut 33-1 NC Acc 2748 x ChicoTifspan x Robut 33-1 TMV 7 x Chico2-5 x Robut 33-1 Virginia 72R x ChicoVirginia 72R x Robut 33-1 Dh 3-20 x Robut 33-1

SOURCES OF EARUNESS. The fo l lowing cul-

t ivars are presently being utilized in the breed-ing p rogram:

Chico — a very early Spanish type, matur ingin 7 5 - 8 0 days, commercial ly unacceptablebecause of extremely small pods; 91176 and91776 —Span ish types, matur ing in 8 0 - 8 5days, bred in Tamil Nadu (India); and Robut33-1 — a Virginia type, maturing in 100 days,released in Andhra Pradesh (India).

CURRENT S T A T U S . The breeding material has

been advanced to the F7 generation by pedigreeor bulk pedigree methods.

Several early matur ing (100-105 days) selec-t ions have been identif ied and are currentlybeing evaluated for yield potential (Table 5).Some of the early f lower ing material identi-f ied in the current rainy season is presented inTable 6.

The cultivars Robut 33-1 and Chico haveproved to be very good combiners for high yieldin certain cases. Late matur ing, high y ie ld ingselections f rom this project are being util ized inthe high y ie ld and quality project.

Breeding for High Yield and Quality

The purpose of this project is to generate base

material w i th high yield potential for diseaseresistance programs, and for areas of the wor ldwhere diseases are not prevalent or protectivemeasures are routinely fo l lowed.

SOURCES. The fo l lowing material is beingutilized in the hybridization program: Cultivarsand landraces f rom different geographicalregions; high yielding and adapted varietiesf rom different countries; and high yieldingbreeding lines developed at ICRISAT.

CURRENT STATUS. The breeding material has

been advanced to F7 generation using pedigreeor bulk pedigree methods. Several promis ingselections are being evaluated for yield poten-tial in different environments dur ing the currentrainy season.

Some of the promising selections made in theF4 and F5 generations, dur ing the postrainyseason of 1979-80, are listed in Table 7.

65

Table 6. Early flowering selections (rainy sea-son 1980).

Selection Days to 75% flowering

Generation (P1 x P2) P1 Selection P2

F1 Ah 330 x 91176 28 18 17Chico x Ah 330 18 17 28Mani Pinter x 91776 24 17 17Chico x NC Acc 344 18 23 29Robut 33-1 x Jacana 24 21 2091176 x NC Acc 2123 17 23 29

F3 M 13 x 91176 25 21 17Chalimbana x 91176 26 23 17DM 1 x 91176 26 18 17RMP 91 x Chico 23 22 18Ah 114 x 91176 24 20 17

T a b l e 7 . H i g h y ie ld ing se lec t i ons (pos t ra inyseason 1 9 7 9 - 8 0 ) .

F4 Generat ion F5 Generat ion

NC Acc 529 x Shulami tNC-Fla-14 x TG 1 Ah 6279 x Spancross

Florigiant x SM 5

GAUG 1 x NC Acc 310

Ah 8254 x JH 62G 37 x SpanhomaFaizpur 1-5 x NC Acc

316NC Acc 63 x TG 17148-7-4-3-12-B x Manf red i

Starr x NC Acc 1107Tifspan x SM 5

Vi rg in ia 72R x NC Acc1107

X14-4-B19-B x SM 5

NC Acc 2750 x Ah 8189NC Acc 316 x NC Acc

310USA 20 x TMV 10

Five hundred and twelve F6 bulks wereevaluated in an 8 x 8 x 8 cubic lattice design aswel l as in a systematic design, which wassuper imposed over the lattice, dur ing the post-rainy season of 1979-80. The purpose of thetr ial was to compare the efficiency of these t w odesigns in evaluation of breeding material. Theresults obtained f rom the cubic lattice analysisare presented in Table 8. Four breeding linessignif icantly outyielded the checks, Robut 33-1and J-11, and 68 more breeding lines were equalin y ie ld to Robut 33-1.

Ay ie ld trial consist ing of progenies of severalplant selections made in the Indian cult ivarRobut 33-1 was carried out dur ing the post-rainy season of 1979-80. Eight selections sig-nif icantly outy ie lded the Robut 3 3 - 1 (Table 9).This cult ivar was developed in Andhra Pradesh,India and originated as a selection f r om a mutant or chance out cross in an exotic intro-duct ion.

New Research Projects

During 1979 and 1980 the fo l l ow ing new breed-ing projects were ini t iated:

Breeding for Resistanceto Aspergillus Flavus

Three breeding lines, w i th dry seed resistanceto invasion by the fungus, are presently beingutil ized as parents in the hybridizat ion program

T a b l e 8 . F 5 y i e l d eva lua t i on (pos t ra iny season1 9 7 9 - 8 0 ) .

Selection TypeDays tomatur i ty

Yie ld(kg/ha)

(Robut 33-1 x NC Acc 2821)F2-B3-B1-B2-B1 SB 121 3827(Robut 33-1 x NC Acc 2698)F2-B2-B1-B1-B1 SB 118 3686(Dh 3-20 x NC Acc 2608)F2-B3-B1-B1-B1 SB 112 3598(2-5 x NC Acc 741)F2-B4-B1-B1-B1 VB 122 3576Robut 33-1a VB 121 2949J 11a SB 112 2915

LSD (0.05) 634.5

a. S tandard checks.

wi th a w ide range of adapted but susceptiblecultivars. The resistant germplasm lines are PI337394F and PI 337409 (Mixon and Rogers1973) and UF 71513 (Bartz et al. 1978).

Breeding for Resistance to Insect Pests

Two germplasm lines, NCAcc 2214 and NCAcc2232, selected for resistance to thr ips and jas-sids (Amin, unpublished data) are being used asparents in an attempt to incorporate resistancein commercial ly accepted cultivars.

Development of Cultivars for Vertisols

Groundnuts g rown in Vertisols, or dark alluvialsoils, often show symptoms of chlorosis due tol ime induced iron chlorosis. Germplasm linesand advanced breeding populat ions are beingscreened for their reaction to i ron, and otherpossible deficiency factors, in Vertisols at theICRISAT Center.

Basic Studies

Some basic genetic studies are being con-ducted in cooperat ion wi th research workers inIndia and by postgraduate students at ICRISAT.Studies on breeding methods have shown highgenetic divergence among Spanish and Valen-cia pa ren t s s u g g e s t i n g t h e u t i l i t y o fSpanish x Spanish, Spanish x Valencia and

66

Tab le 9 . Na tu ra l hybr id t r i a l (postra iny season 1 9 7 9 - 8 0 ) .

Selections f rom Days to Yield Shel l ingRobut 33-1 Type matur i ty (kg/ha) (%)

11-7-B1-B1-B1 VB, SB, IB 119 2680 7721-11-B1-B1-B1 SB 119 2683 6610-3-B1-B1-B1 SB 119 2653 767-6-B1-B1-B1 VB, IB 119 2650 7013-6-B1-B1-B1 VB, SB, IB 119 2628 71

12-10-B1-B1-B1 VB, IB 119 2620 7550-1-B1-B1-B1 VB 119 2527 71

24-16-B1-B1-B1 SB 119 2488 72

Robut 33-1 (parent) VB 119 2013 70

LSD (0.05) 389.4

Valencia x Valencia crosses (Arunachalam etal. 1980).Similar results have been obtained inthe USA by Wynne et al (1970).

Uni form non-nodulat ing lines of groundnutshave been developed through w ide crosses andthe genetics of non-nodulat ion has been de-termined (Nigam et al. 1980).

Some yield trials conducted dur ing rainy andpostrainy seasons at the ICRISAT Center haveshown strong variety x season interactions.This suggests the need of identif ication ofvarieties for each season. This is particularlyimportant for India where presently 8% of thetotal crop is g rown under postrainy condit ions.

Cooperation with National Programs

The breeding mater ial , generated w i th desir-able characteristics at ICRISAT, is freely distr i-buted to breeders in national programs toenable them to carry out f inal selection undertheir local condit ions. So far, 2792 selectionshave been supplied to breeders in 14 countries(Table 10). Al l the breeders, w h o received mate-rial, were able to make useful selections out ofbreeding populat ions suppl ied. Some selec-t ions have done exceedingly well in trials inTamil Nadu (India). Another selection, matur ingin 85 days, has been found suitable for summercult ivat ion in Maharashtra.

As the breeding program develops, a consi-derably greater volume of material wi l l becomeavailable for distr ibut ion to any country whichrequests it.

T a b l e 1 0 . B r e e d i n g m a t e r i a l s u p p l i e d t oc o o p e r a t o r s b y I C R I S A T , 1 9 7 8 -1 9 8 0 .

Number

High- Selections Rust-y ielding wi th resistant

Country selections earliness material

Bangladesh 6 14Benin 80 55 68Burma 10 6China 8 2 40

Ghana 15 19

India 1121 858 288

Japan 3

Puerto Rico 14

Senegal 30 20 40

Sri Lanka 17 4 4

Tanzania 9 4

Thailand 10 20 10

Upper Volta 5 6

ReferencesA B D O U , Y. A - M . 1966. The source and nature of resis-

t ance in Arachis spp to Mycosphaerella arachidicola Jenk. and M. berkeleyii Jenk. and fac-tors inf luencing sporulat ion of these fung i . Unpub-l ished Ph.D. thesis, Department of Plant Pathology,Nor th Carolina State Universi ty, Raleigh, Nor thCarol ina, USA. Universi ty Micro f i lms, Inc. Ann Ar-bor, Mich igan, USA.

67

A S O O U , Y. A - M . , GREGORY, W. C, and COOPER, W. E.

1974. Sources and nature of resistance to Cercos-pora arachidicola Hor i and Cercosporidium per-sonatum (Berk and Curtis) Deighton in Arachis species. Peanut Science 1: 6 - 1 1 .

A R U N A C H A L A M , V., BANDYOPADHYAY, A., N I G A M , S. N.,

and G I B B O N S , R. W. 1980. S o m e basic results ofappl ied va lue in g roundnu t breeding. Pages 1 - 1 9 INProceedings of the National Seminar on the Appl i -cat ion of Genetics to Improvement of Groundnut .16-17 Ju ly , 1980. School of Genetics, Tami l NaduAgr icul tura l Univers i ty , Coimbatore-641 003, India.

BAILEY, W. K., STONE, E., BROMFIELD, K. R., and GARREN,

K. H. 1973. Not ice of release of peanut germp lasmwi th resistance to rust. V i rg in ia Agr icu l tura l Experi-ment Stat ion , Blacksburg, Virg in ia and USDA, Ag-r icul tural Research Service, Wash ing ton , D. C. 3 pp.

BARTZ, J . A., NOROEN, A. J. , LAPRADE, J . C, and DE-

M U Y N K , T . J . 1978. Seed t o l e rance i n peanu t s(Arachis hypogaea L.) to members of the Aspergi l -lus flaws g roup of f ung i . Peanut Science 5: 5 3 - 5 6 .

BEUTE, M. K., W Y N N E , J. C, and EMERY, D. A. 1976.

Registrat ion of NC 3033 peanut germplasm. CropScience 16: 887.

BROMFIELD, K. R., and BAILEY, W. K. 1972. Inheritance to

Puccinia arachidls in peanu t . P h y t o p a t h o l o g y62: 748 (Abstract)

BUNTING, A. H., G REGORY, W. C, M A U B O U S S I N , J. R., and

R Y A N , J . G. 1974. A p r o p o s a l f o r research ongroundnuts (Arachis) by ICRISAT. pp 1-38. ICRISAT,m lmeo .

FILHO, A. S., and de MORAES, S. A. 1977. Observacoes

sobre a incidencia de Cercosporioses em cult ivaresde a m e n d o i m (Arachis hypogaea L.) Revista de Ag-r iculture 52: 3 9 - 4 6 .

GIBBONS, R. W. 1976. Groundnut Improvement Pro-g r a m m e — Priori t ies and Strategies, pp 1-26.ICRISAT mimeo.

G IBBONS, R. W. 1980. Adaptat ion and ut i l izat ion ofg roundnuts in d i f ferent env i ronments and fa rm ingsystem. Pages 483-493 in Advances in LegumeScience, eds. Summer f ie ld and Bunt ing 1980.

H A M M O N S , R. O. 1977. Groundnut rust in the Uni tedStates and the Caribbean. Pest Art ic les and NewsSummar ies , 23: 300-304.

H A M M O N S , R. O., SOWELL, G. Jr., and S M I T H , D. H. 1980.

Registration of Cercospora arachidicola resistantpeanut germplasm. Crop Science 20: 292.

H A S S A N , H . N., and BEUTE, M. K. 1977. Evaluat ion of

resistance to Cercospora leaf spot in peanut ge rm-plasm potentially useful in a breeding program. PeanutScience 4: 78-83.

M A Z Z A N I , B., and HINOJOSA, S. 1961. Diferencias var-

letales de suscept ibl l idad a la roya del man i en Ven-ezuela. Ag ronomia Tropical 11 : 4 1 - 4 5 .

M E L O U K , H. A., and B A N K S , D. J . 1978. A me thod of

screening peanut genotypes fo r resistance to Cer-cospora leaf spots. Peanut Science 5: 112-114.

M I X O N , A. C, and ROGERS,K. M. 1973. Peanut acces-sions resistant to seed in fect ion by Aspergillus flavus. A g r o n o m y Journal 65: 560-562 .

N I G A M , S. N., A R U N A C H A L A M , V., G IBBONS, R. W.

BANDYOPADHYAY, A., and NAMBIAR, P. T. C. 1980.

Genetics of non-nodulat ion in g roundnut (Arachis hypogaea L ) . Oleagineux (In press).

N O R D E N , A . J . 1973. B reed ing o f t he c u l t i v a t e dgroundnut (Arachis hypogaea L ) . Pages 182-184 i nPeanuts-Culture and Uses. Amer ican Peanut Re-search and Education Associat ion, Inc., USA.

SOWELL , G. Jr., S M I T H , D. H. and H A M M O N S , R. 0 .1976 .

Resistance of peanut plant in t roduct ions to Cercos-pora arachidicola. Plant Disease Reporter 60:494-498.

S U B R A H M A N Y A M , P., REDDY, D. V. R., G IBBONS, R. W.,

R A O , V. R., and GARREN, K. H. 1979. Current distr ibu-t ion of g roundnut rust in India. Pest Art ic les andNews Summar ies. 25: 25-29 .

SUBRAHMANYAM, P., GIBBONS, R. W., N I G A M , S. N., and

R A O , V. R. 1980a. Screening methods and fur thersources of resistance to peanut rust. Peanut Science7: 10-12.

S U B R A H M A N Y A M , P., M C D O N A L D , D., G IBBONS, R. W.,

N I G A M , S. N. and NEVILL , D. 1980b. Resistance toboth rust and late leaf spot in some cult ivars ofArachis hypogaea L. Proceedings, Amer ican PeanutResearch and Education Associat ion, USA. (Inpress).

W Y N N E , J. C, EMERY, D. A. , and RICE, P. W. 1970.

Combing abi l i ty est imates in Arachis hypogaea L.II .Field per formance of Fi hybr ids. Crop Science 10:713-715.

68

Session 3 — Genetics and Breeding

Discussion

T. P. YadavaFor screening material against drought andinsects, do you depend upon natural infesta-t ion or some laboratory technique?

S. N. NigamDrought screening has not yet been started atICRISAT. Development of a drought screeningtechnique wou ld be a main pr ior i ty of thephysiology program, which has recentlystarted. Screening for resistance to insectsdepends to a large degree upon natural infes-tat ion, but some useful screening can be donein the screenhouse or laboratory.

K. S. LabanaHas ICRISAT got h igh-qual i ty and h igh-yielding lines that are better than the M-13spreading cultivar.

S. N. NigamHigh yield is not restricted to any one group ofcultivars or botanical type. We have somehigh-yielding runner lines that are better thanM-13 when tested at ICRISAT. Widescale test-ing of these lines in different environmentshas not been done as yet.

A. S. ChahalWhen the 1-9 scale for scoring leaf spot dis-eases in groundnut is used, an entry showing50 to 100% defol iat ion is scored as 9. Someleaves fall due to matur i ty and some leaveswi th even one spot may drop off the plant.Wou ld such leaves be considered under de-fol iat ion due to disease? If not, what is theexplanation?

P. SubrahmanyamDefol iat ion or wi ther ing depends upon thecultivar, severity of disease and other en-v i ronmental factors. Susceptible varietieswi ther very rapidly under high disease pres-sure whereas resistant varieties show s low

disease development wi th perhaps a l itt lewither ing towards maturity. It is compara-tively easy to select resistant plants.

J. S. Chohanin spite of all quarantine efforts, some patho-gens do get moved f rom country to country.Has any new pathogen been introduced toIndia wi th groundnut germplasm?

V. R. RaoNo. PMV-infected plants have been found inthe Plant Quarantine Glasshouses and wereimmediately destroyed. This serves as anexample of how stringent quarantine re-sources do result in the interception of dis-eases.

V. RagunathanWas PMV introduced to India through ICRISATgermplasm introductions, or was it alreadypresent in India but had not been detected?

R. W. GibbonsPMV has a wor ldwide distr ibut ion. It was firstnoted in India in the north of the country and itwas also reported present in Pakistan someyears ago, so it has probably been here forsomet ime. Because of the mi ld symptoms thisdisease has been overlooked in many coun-tries.

K. S. LabanaHas ICRISAT got any groundnut lines showingdeterminate f lowering?

V. R. RaoThe germplasm collection is yet to be checkedfor this character.

N. D. DesaiHas ICRISAT any accession available for useas donor parents wi th drought tolerance anddormancy in Spanish bunch types?

69

V. R. RaoScreening for drought tolerance w i l l com-mence short ly at ICRISAT but we have somedrought resistant material f r om Senegal in ourgermplasm col lect ion and we have a few linesof Spanish types showing about 15 dayspost harvest dormancy.

A. B. SinghIs there any l ine resistant to bud necrosis anddry root rot? Are there any resistant or tolerantlines to wh i te grub?

P. W. Am inWe have extensively screened our germplasmcollection but we have not found any lineresistant to bud necrosis. Whi te grub does notoccur in suff icient numbers to do any mean-ingful screening at the ICRISAT Center.

B. S. GillI wou ld like to hear the v iews of Dr. Nordenregarding plant types that can be util ized inselection for high y ie ld.

A. J. NordenA scale has been developed and is used in

Florida. Many factors are involved.

S. H. PatilCan Dr. Norden, f r om his great experience inbreeding improved varieties of groundnut ,indicate appropriate hypothetical ideotypesfor obtaining the highest yields in dif ferentbotanical groups of groundnut varieties?

A. J. NordenNo, I wou ld not wan t to at tempt to define a hypothetical ideotype for obtaining best yieldsin the different botanical groups of groundnutcultivars. It is dependent on too many var i -ables, such as the cl imate, the soils, and theend-use of the crop. For example, the ideotypefor obtain ing best yields in a fu l ly mechanizedproduct ion wou ld not f i t a situation in whichthe crop is produced w i th hand labor. In theformer, low-growing plants wi th spreadingprostrate g rowth habit and vines entwined arepreferred, but they wou ld not be the idealwhen the product ion, harvesting, and pickingare accomplished by hand labor. However, I think one could def ine ideotypes for the diffe-rent regions and periods in t ime.

70

Session 4

Cytogenetics and Utilization ofWild Species

Rapporteurs: V. R. RaoJ. H. Wil l iams

Chai rman: V. S. Raman

Cytogenetic Investigations in the Genus Arachis

H. T. Stalker*

The genus Arachis L. is a New Wor ld taxonnative to South America. Species are distr i-buted over a w ide range of environments f romsouth of the Amazon to 34°S latitude, and f romthe Atlantic shore to the eastern slopes of theAndes. Peanuts are most ly found in sandy soilsin open grasslands or in broken forests (Greg-ory et al. 1980). Speciation has generally fo l -lowed drainage basins and riverbeds, wh i le thegreatest diversity is found in the headwaters ofthe Paraguay River.

Twenty-two species have been described andpossibly 5 0 - 8 0 other distinct taxa are found innature. Gregory et al. (1973) grouped thespecies into seven botanical sections. Intersec-t ional hybridization is uncommon whi le in-trasectional hybr ids are more easily producedunder experimental condit ions (Gregory andGregory 1979). Barriers to interspecific hybr id i -zation are somet imes great and biosystematicrelationships wi th in some groups, i.e., sectionRhizomatosae, are not ful ly understood.

The cult ivated species, Arachis hypogaea L,belongs to the section Arachis along w i th atleast one other tetraploid (A. monticola Krap etRig.) and 10 diploid species, and hybridizationbetween the cult ivated species and other mem-bers of section Arachis is possible (Smartt andGregory 1967; Raman 1967; Gregory and Greg-ory 1979). When the wi ld species of sectionArachis are used as female parents, the successrate of producing hybrids is usually greater.Arachis monticola Krap. et Rig. and A.hypogaea are apparently completely compat i -ble.

* Assistant Professor, Department of Crop Science,North Carol ina State Univers i ty , Rale igh, Nor thCarolina 27650, USA.

Note: Paper No. 6625 of the Journal Series of theNorth Carolina Agr icu l tura l Research Service,Raleigh, USA. This research was part ial ly sup-p o r t e d by SEA/CR Research A g r e e m e n t5 9 0 1 - 4 1 0 - 9 - 3 6 7 .

Cytogenetic studies over the past four de-cades have included count ing the chromo-some numbers of species and their interspecifichybrids, identi fying cytologically rare plantssuch as aneuploids, and observing meioticbehavior of species and hybrids.

This paper attempts to summarize the ac-cumulated cytogenetic evidence concerningArachis species and their hybr id derivatives.Gregory and Gregory (1979) and Smartt (1979)have questioned the authenticity of many hy-brids reported in the literature, especially thoseclaimed to have been produced by Raman(1976) and Varisai Muhammad (1973a,b,c).Only hybr ids of unquestioned identity are thusincluded in this report.

Cytogenetic informat ion can conveniently bedivided into studies of somatic and meioticchromosomes, and each major group wi l l bediscussed separately in this report.

Somatic Chromosomes

Chromosome Numbers

The first cytogenetic informat ion presented forArachis was by Badami (1928) w h o reported a somatic chromosome number of 2n = 20 forthe cult ivated peanut, A. hypogaea. Other in-vestigators later conf i rmed the true number as2n = 40 (Kawakami 1930; Husted 1931). Greg-ory (1946) reported a chromosome number of2n = 40 for a w i ld species, A. glabrata Benth,and one year later Mendes (1947) reportedseveral d iploid species in the genus. Poor qua-lity preparations have hindered many analyses,and not unti l Fernandez (1973) publishedtechniques for Arachis chromosomes weremany of these diff icult ies overcome.

Listed in Table 1 are the named species andcorresponding chromosome numbers. A l -though Gregory and Gregory (1979) d id not listcollection numbers wi th many of their parentalassignments, they presented a general pattern

73

for d ip lo id and tetraploid species in the genus.Most Arachis species are d ip lo id wh i le a fewmembers of section Arachis and most speciesof section Rhizomatosae are tetraploid. Be-

cause the tetraploid species of sections Arachis and Rhizomatosae wi l l not hybridize, poly-ploidy probably evolved independently in eachof the groups.

T a b l e 1 . N a m e d spac ies o f Arachis a n d co r respond ing c h r o m o s o m e n u m b e r .

Section/species Chromosome ReferenceNo

ArachisA. batizocoi Krap. et Greg. 20 Smar t t and Gregory (1967)A. pusilla (correct ly A. duranensis) Krap. et Greg. nom. nud. 20 Krapovickas and Rigoni (1957)A. spegazzinii Greg. et Greg. nom. nud. 20 Gregory and Gregory (1979)A. stenosperma Greg. et Greg. nom. nud. 20 Gregory and Gregory (1979)

A. ipaensis Greg. et Greg. nom. nud. 20 Gregory and Gregory (1979)A. he/odes Mar t ius ex Krap. et Rig. 20 Smart t and Gregory (1967)A. villosa Benth. 20 Krapovickas and Rigoni (1949)A. diogoi Hoehne. 20 Mendes (1947)

A. cardenasii Krap. et Greg. nom. nud. (10017 GKP) 20 Smart t and Gregory (1967)

A. chacoense Krap. et Greg. nom. nud (10602) 20 Smar t t and Gregory (1967)A. hypogaea L. 40 Kawakami (1930)A. monticola Krap. et Rig. 40 Krapovickas and Rigoni (1957)

Erectoides

A. guaranitica Chod. et Hassl. 20A. tuberosa Benth. 20A. benthami HandroA. martii Handro

2020

Smart t and Gregory (1967)

A. paraguariensis Chod. et Hassl. 20 Smart t and Gregory (1967)

A. oteroi Krap. et Greg. nom. nud. 20 Smart t and Gregory (1967)A. rigonii Krap. et Greg. 20 Krapovickas and Gregory (1960)A. lignosa Chod. et Hassl. (10598) Caulorhizae 20 Smart t and Gregory (1967)A. repens HandroA. pintoi Krap. et Greg. nom. nud.

2020

Conagin (1963)

RhizomatosaeA. burkartii Handro 20 Gregory and Gregory (1979)A. glabrata Benth. 40 Gregory (1946)A. hagenbeckii Harms 40 Krapovickas and Rigoni (1957)

ExtranervosaeA. marginata Gard. 20 Mendes (1947)

A. lutescens Krap. et Rig. 20 Conagin (1963)

A. villosulicarpa Hoehne 20 Mendes (1947)A. macedoi Krap. et Greg. (10127) 20 Smar t t and Gregory (1967)A. prostrata Benth. 20 Mendes (1947)

Ambinervosae

None named 20

TriseminalaeA. pusilla Benth. 20

Note. nom, nud. = species which are not validly described In the botanical literature.

74

Aneuploidy

Plants of A. hypogaea w i t h 41 c h r o m o s o m e s

plus a f r a g m e n t w e r e reported by Husted

(1936). Spielman et al. (1979) f o u n d a series of

4 2 - 4 4 c h r o m o s o m e plants after observing

plants g r o w n f r o m small seeds. Other aneu-

ploids were f o u n d after ionizing radiation

(Madhava Menon et al. 1970; Patil 1968; Patil

and Bora 1961) and chemical t reatments (Ashri

et al. 1977).

Aneuplo idy in Arachis is c o m m o n l y observed

after colchicine treatment of treat ing inter-

specific hybrids. Smartt and Gregory (1967)

and Spielman et al. (1979) reported a range of

chromosome numbers in colchicine-treated

A. hypogaea x diploid section Arachis hybrids.

After several generations of selfing a 6x

(A. hypogaea x A cardenasii Krap. et Greg. nom.

nud.) interspecific hybr id, Simpson (1976) re

ported progeny w i t h c h r o m o s o m e numbers

ranging f r o m 3 2 - 4 8 . However, w h e n selecting

for agronomic f i tness. Stalker et al. (1979) f o u n d

all selected plants in the populat ion had 40

chromosomes. Thirty-one and 32-chromo-

some plants also resulted f r o m intersectional

hybridization of 4x (section Erectoidesxsect ion

Erectoides)x2x section Arachis species (Stalker

1978; in review). Trispecific hybr ids of A.

hypogaeax4x section Arachis amphid ip lo ids

also resulted in a f e w aneuploid progeny

(Stalker, unpubl ished data).

A l t h o u g h a n u m b e r of aneuploid plants have

been d o c u m e n t e d , complete aneuploid series

of g e n o m e s have not been produced. Sets of A.

hypogaea aneuploids need to be created and

maintained so that genetic analyses of c h r o m o -

somes can be performed. Even t h o u g h aneup-

loids recovered after interspecific hybridizat ion

(and recovered 40-chromosome interspecific

hybrids) are suspected of having w i l d species

c h r o m o s o m e s , t h e cytological make-up of hyb-

rid derivatives is unknown. Karyotyping w i l d

and cult ivated species c h r o m o s o m e s along

w i t h mainta in ing cytological ly un ique plants

wi l l aid in t h e uti l ization of aneuploids.

Chromosome Morphology

The c h r o m o s o m e s of A. hypogaea are small

w i t h most ly median centromeres (Chimpu

1930). A l t h o u g h karyotyping Arachis c h r o m o

somes is d i f f i c u l t several dist inct ive c h r o m o -

somes have been f o u n d . Husted (1933, 1936)

reported one c h r o m o s o m e pair w h i c h was dis-

t inctly smaller than other chromosomes of the

cult ivated species (A chromosomes) and one

pair w i t h a secondary constr ict ion (B c h r o m o -

somes). He analyzed the c h r o m o s o m e s of

several varieties but was unable to detect differ-

ences. Babu (1955) f o u n d several different types

of secondary constrictions in 14 A. hypogaea

varieties. Tennessee Red was the only variety

w i t h o u t a secondary constrict ion in his study.

D'Cruz and Tankasale (1961) w e r e also able to

cytologically distinguish four A. hypogaea vari-

eties based on centromere posit ions and

c h r o m o s o m e lengths.

The w i l d species A. villosa var correntina

Benth has a small (A) c h r o m o s o m e simi lar to

that f o u n d in A. hypogaea (Raman 1959;

Smartt 1965). Smartt (1965) observed the small

A chromosomes in several other members of

section Arachis; this dist inctive pair was not

present in t h e section Erectoides species A.

paraguariensis Chod. et Hassl. (9646 GKP).

F r o m p h o t o m i c r o g r a p h s p r o d u c e d b y

Krapovickas et al. (1974), A. batizocoi Krap. et

Greg, apparently d id not have the A c h r o m o -

some f o u n d in other section Arachis species.

Smart t et al. (1978) later conf i rmed the absence

of this dist inctive c h r o m o s o m e pair in A.

batizocoi.

The c h r o m o s o m e s of e ight section Arachis

species range in length f r o m 1 - 4 µ m in the

metaphase stage of mitosis (Stalker and Dal-

macio, in review). Each of the 10 h o m o l o g o u s

chromosomes of each species studied was

identif iable based on centromere posit ion,

length, secondary constrictions, and differential

staining of heterochromatic and euchromatic

regions of the chromosomes. Arachis batizocoi

had a unique karyotype wi th 1 submedian (S/L

arm=0.33-0.64) and 6 slightly submedian (S/L

arm=0.65-0.79) chromosomes and a secondary

constriction on the long arm of c h r o m o s o m e 2.

Arachis cardenasii had many sl ightly subme

dian chromosomes and was t h e only species

observed w i t h secondary constr ict ions on t w o

c h r o m o s o m e s (5 and 10). Most of t h e other

species of section Arachis most ly had median

or sl ightly submedian chromosomes. Secon

dary constrictions were on t h e median c h r o m o

somes of A. chacoense Krap. et Greg. nom. nud.,

A. duranensis Krap. et Greg. nom. nud., and A.

stenosperma Greg, et Greg. nom. nud., w h i l e

75

none were found for species A. villosa, A.correntina Krap. et Greg. nom. nud., or A.spegazzinii Greg, et Greg. nom. nud. Afterc o m b i n i n g fer t i l i t y data w i t h karyo typeanalyses, Smart t et al. (1978a,b) and Stalker andDalmacio (in review) proposed that sectionArachis has t w o dist inct genomes. Most specieshave the A genome w h i l e A batizocoi has the B genome. Based on ly on karyological evidence,subgroups of the A genom e were also proposedas f o l l o w s : A1 =A. cardenasii; A2 =A. chacoense,A. duranensis, and A. stenosperma; and A3 = A. correntina, A. spegazzinii, and A.villosa (Stalker and Dalmacio, in review). Table2 lists the eight species of section Arachis analyzed and corresponding chromosomemorpholog ica l traits (Stalker and Dalmacio, inreview).

Chromosome Behavior

SpaciesAll d ip lo id species of the genus Arachis have 10bivalents and regular meiosis (Resslar and Gre-gory 1978; Smart t et al. 1978a,b; Raman 1976;Stalker and Wynne 1979). Tetraploids of sectionArachis, A. hypogaea, and A. monticola, alsobehave cytological ly like d ip lo ids and usuallyhave 20 bivalents (Raman 1976). However, tet-

raploid members of section Rhizomatosae mayhave 1 -4 mult ivalents per cell (Raman 1976).

Many intraspecific hybr ids between sub-species of A. hypogaea produce sterile or " m u t -an t " progeny in the second or later generat ions.Genetical or cytological divergence amongsubspecif ic groups may offer an explanat ion forthe steril i ty. Husted (1936) observed bivalentsplus a f ew univalents, tr ivalents, and quadr iva-lents in Virginia x Spanish varietal hybrids.Both Husted (1936) and Raman (1976) con-cluded that structural dif ferences may be pre-sent between the t w o botanical types. Tofurther characterize the meiot ic behavior ofintraspecific hybr ids of A. hypogaea, Stalker(unpublished) cytological ly analyzed parentsand crosses of Spanish, Valencia, and Virginiavarieties (Table 3). The parents in the studyrepresented f ive gene centers of SouthAmerica. Bivalents were observed in most pa-rents and hybrids, but univalents and mul t iva-lents were also recorded at a low frequency.Only one hybr id combinat ion, Valencia x Vir-ginia, had a relatively high frequency of univa-lents (Table 3) wh ich may indicate structuraldifferences between t h e t w o botanical varieties.Fur ther analyses, especial ly of somat icchromosome morphology, are needed beforeconclusions concerning specific ch romosomedifferences among subspecif ic groups can bemade.

T a b l e 2 . C h r o m o s o m e va r i a t i on a m o n g s e c t i o n Arachis spec ies o f t h e genus Arachis (abs t rac tedf r o m S t a l k e r a n d D a l m a c i o , i n r e v i e w ) .

Chromosomes

Tota lW i th Sl ight ly Tota l RatioProposed secondary Sub- sub- g e n o m e chrorn

Species g e n o m e s * constr ic t ion median med ian length 10:1

A. cardenasii A1 5,10 2,4,5,6, 28.05 .63

A. chacoense A2 7 77,9,102,5,9,10 29.03 .56

A. duranensis A2 6 6 5,9 26.48 .41A stenosperma A2 5 5,6,9,10 27.46 .44A. correntina A3 9 1,2,5 29.89 .51A. spagazzini i A3 9 10 24.29 .47A. villosa A3 9 7,10 25.72 .50A batizocoi B 2 1 2,3,4,5,

6,925.49 .64

a. Subgroups at t he A g e n o m e (A1 , A2 a n d A3 ) w e r e p roposed based on karyo log ica l analyses and do no t necessar i ly cor respondw i t h plant habi t no r hyb r i d fer t i l i ty .

76

Table 3. Melotic behavior of Spanish, Valancia and Virgini a varieties of A. hypogaea and theirintraspecific hybrids.

Number Avg chrom assoc/cell

Identity Genotype Plant Cell I II III IV

Spanish (Sp)Valencia (Val)Virginia (Va)

343

353

75125

750.010.08

19.8519.8619.96

0.050.06

Sp x SpVal x Val

33

56

125150 0.07

19.9019.89 0.01

0.050.02

Sp x ValVal x Sp

43

56

111175

0.140.15

19.8919.86

0.01 0.010.01

Val x VaVa x Val

41

51

18025

0.510.08

19.5919.96

0.01 0.08

Sp x VaVa x Sp

41

62

15050

0.070.12

19.9319.94

0.01

Meio t i c Behavior of In terspeci f icHybr ids

Meiosis in F1 hybr ids between the two tetrap-loid species of section Arachis, A. hypogaea andA. monticola, is regular, and 20 bivalents areusually observed in pol len mother cells. Arachis hypogaea and A. monticola apparently have thesame g e n o m e s and gene exchange f ree lyoccurs in hybrids.

Arachis hypogaea also hybridizes w i th d ip-loid members of section Arachis. The F1 hybr idsare sterile and cytological analyses reveal thatunivalents and bivalents are the most c o m m o nchromosome conf igurat ions in pollen mothercells. The frequency of tr ivalents in meiot ic cellsis dependent upon the wi Id species parent usedin crosses. For example, Smart t (1965) reportedan average of 0.95 tr ivalents for A. hypogaea x A. villosa var. correntina, 2.15 tr ivalents fo r A.duranensis hybrids, and 3.40 tr ivalents when A.helodes was used as a parent. Meiotic analysesof tr iploid hybrids in Arachis do not reveal wi thwh ich genome(s) the w i l d species were paired.At least in cells w i th tr ivalents, cult ivated-cult ivated, and cul t ivated-wi ld species chromo-some associations occurred. Assuming A.hypogaea has two distinct genomes, the grea-ter the chromosome homology between thew i ld and cult ivated species, the fewer tr ivalentswou ld be expected because homologouspair ing among genomes wou ld be restricted by

the relatively rapid synapsis of homologues. A detailed analysis of pairing relationships be-tween A. hypogaea varieties and the sectionArachis d ip lo id species wou ld greatly add to ourunderstanding of genomic relationships amongthe species.

Fertil ity can be restored after colchicinetreatment of t r ip loid interspecific hybrids. In 6x(A. hypogaea x A. cardenasii) hybrids, meiosisis apparently irregular w i th up to 32 univalentsformed dur ing meiosis in 60-chromosomeplants (Spielman et al. 1979). The meiotical lyunstable gametes are apparently el iminatedbefore seed set, however, because progenyf rom these hybrids are stable at the 60-chromosome ploidy level (P. Moss, personalcommunica t ion) . In 6x hybr ids between A.hypogaea and A. chacoense between 2 and 18univalents per cell were observed (Companyand Stalker, unpublished). Since every chromo-some has a homologue in the 6x plants, genescausing asynapsis must be present. Companyand Stalker (unpublished) also observed pro-geny f r om 60-chromosome A. hypogaea x chacoense x cardenasii, and x batizocoi hybridderivatives and the offspring are apparentlystable at the 60-chromosome level. In the sec-ond to f i f th generations after self-pol l inating 6x(A. hypogaea x A. batizocoi) hybr ids, the usualcytological conf igurat ion is bivalents and me io -tic processes appear normal (Stalker, unpub-lished). Since strong selection pressure for

77

viable seeds occurs in seed nurseries to main-ta in the germplasm, corresponding pressuresare exerted in the interspecific hybr ids for nor-mal meiosis and viabi l i ty. Diploidizat ion w o u l dthus be expected to occur rapidly in po lyp lo idinterspecific hybr ids.

Meiosis of most d ip lo id x d ip lo id sectionArachis interspecific hybr ids is normal and 10bivalents are observed in F1 pol len mother cells(Raman and Kesavan 1962; Resslar and Greg-ory 1979; Stalker and Wynne 1979). The excep-t ion is when A. batizocoi is used as a parent.These F1 hybr ids are sterile and have irregularmeiosis (Gibbons and Turley 1967; Smar t t e ta l .1978a,b; Stalker and Wynne 1979). As indicatedin the section concerning ch romosome mor -phology, A. batizocoi has ch romosome mor -phologies different f r om the other observedspecies of section Arachis, and meiot ic andmitot ic analyses conf i rm the presence of twogenomes in section Arachis. Few analyses ofinterspecific hybr ids in other botanical sectionsof the genus have been recorded, al though inone sect ion Erectoides x sect ion Erectoides hybrid (10034 GKP x 9646 GKP), the F1 wassterile and meiotic cells averaged 1.2 univalentsand 9.4 bivalents per cell (Stalker, unpubl ished).Structural differences are apparently found be-tween species of sections other than sectionArachis.

Amphid ip lo ids produced f r om dip lo id fert i lesection Arachis interspecific hybr ids are male-fert i le, but most plants do not produce manyseeds. Amphid ip lo ids behave meiot ical ly eitheras dip lo ids w i th 20 bivalents or may have asmany as 9 quadrivalents per pol len mother cell(Stalker and Dalmacio, unpubl ished). Based onobservat ions of only a l imi ted number of plants,t r ispeci f ic A. hypogaeax4x sect ion Arachis amphidiploids have 40 -60% ferti l ity and manyunivalents per pol len mother cell. Meiosis isirregular w i th many laggards and bridges(Stalker, unpubl ished). The analysis of tris-pecific hybr ids is compat ib le w i th previousevidence for A. hypogaea having t w o genomeswi th one being the A genome of many sectionArachis d ip lo id species.

Intersectionsl hybr ids are dif f icult to produceand cytological analyses are correspondinglyless frequent. Stalker (1978; in review) reportedmeiot ic ch romosome behavior in (4x sectionErectoides amphid ip lo ids x 2xsect ion Arachis)F1 h y b r i d s . T h e s t e r i l e A rigonii (10034

GKP) x Arachis sp 9841 GKP F1 hybr id was col-chicine treated after which a fert i le amphid ip lo idwas found. This plant was hybridized wi th A.stenosperma (410 HLK) and A. duranensis (7988K). The result ing 3 0 - 3 2 chromosome of fspr inghad most ly univalents and bivalents plus a fewtrivalents. The author concluded that intersec-t ional ch romosome associations were presentin the hybr ids and possibly a common genomewas present between sections Arachis andErectoides. Complex section Erectoides (E)xsection Rhizomatosae (R) hybr ids producemostly bivalents dur ing meiosis (Stalker, un-published). Because of the p lo idy levels andcomplexi t ies of most exist ing hybrids, conclu-sions concerning intersectional chromosomeassociations are dif f icult to make. However, inone hybrid combinat ion 4x[GKP 10034 (E)xGKP9841 (E)] x4x [GKP 9841 (E)xGKP 9570 (R)] thenormal ly 20 bivalents observed, most probablyrepresented intersectional chromosome associ-ations (Stalker, unpublished).

D i s c u s s i o n

Careful analyses of section Arachis chromo-somes have revealed enough var iat ion to iden-t i fy the 10 homologues. As chromosomes be-come more condensed they are proport ionatelymore dif f icult to karyotype. At least t w ogenomes exist in the section Arachis. The A genome includes most species of the sectionand the known B genome current ly consists ofonly A. batizocoi. At least f ive species can becytologically identi f ied in section Arachis; another three cytological ly similar species (A.correntina, A. spegazzinii, and A. villosa) canonly be dist inguished after many cells areanalyzed.

interpretat ion of chromosome pair ing rela-t ionships of d ip lo id interspecific hybrids is gen-erally s t ra ight forward. In section Arachis, A.batizocoi hybr ids have irregular meiosis and aresterile. Al l other d ip lo id interspecific hybr idsinvolv ing species of this section thus faranalyzed have 10 bivalents at metaphase I.Semisteri l i ty is common in most interspecifichybr ids even though meiosis is regular. Morevariat ion in ch romosome morpho logy wasfound in somatic section Arachis species thanexpected, based on previous observat ions ofmeiot ic chromosome associations in pol lenmother cel ls. H o m o l o g o u s c h r o m o s o m e

78

pair ing must occur at a h igh frequency ininterspecific hybr ids of section Arachis.

Polyploidy is naturally present in t w o sectionsof the genus and colchicine treatment hasresulted in induced polyplo ids in several others.Analyses of chromosome numbers to identifyhybr ids and then to determine intergenomicchromosome relat ionships in hybrids wi th2x=40 to 60+ are desirable. Interpretation ofc h r o m o s o m e pa i r ing re la t ionships in po ly -ploids is sometimes difficult. Because of thesmall ch romosome size, meiot ic Arachis chromosomes are extremely dif f icult to iden-tify. Whi le mult ivalents in tetraploids may indi-cate intergenomic homologies, most ly only oneor t w o quadrivalents per cell are observed.Also, the same or dif ferent ch romosome maybe pair ing in different cells so the amount ofpossible gene exchange is di f f icult to determinein most hybrids. Bivalent format ion in poly-ploids generally indicates distinct genomes andl imited intergenomic interaction. However,when only bivalents are present, conclusions asto interaction cannot be easily drawn. Whi leformat ion of pentavalents or hexavalents inal lohexaploids indicates homology among allthree genomes, format ion of only quadrivalentswou ld not prove nor disprove genomic rela-t ionships.

Based on the extensive hybridizat ion pro-gram conducted by Gregory and Gregory (1979),at least f ive genomes have probably evolved inthe genus Arachis, inc luding: AM (Ambiner-vosae), C (Caulorhizae), E (Erectoides), EX (Ex-tranervosae), and T (Triseminalae). Tetraploidmembers of section Rhizomatosae hybridizewi th sections Arachis and Erectoides in rela-t ively high frequency. Rhizomatosae may thushave a c o m m o n genome w i th Arachis andErectoides. The relat ionships are somewhatconfusing because section Arachis probably didnot evolve f rom section Rhizomatosae, or viceversa. Present evidence indicates that sectionArachis has two genomes and members w i theither the A genome (i.e., A. duranensis or A spegazzinii) or w i th the B genome (i.e., A.batizocoi) wi l l hybridize wi th the same sectionRhizomatosae col lections. However, othermembers w i th the A genome (i.e., A villosa, A.correntina, A.cardenasii, and A. chacoense)w i l l n o t hyb r i d i ze w i t h the s a m e sec t ionRhizomatosae col lect ions (Gregory and Greg-ory 1979). The crossing relat ionships along w i th

karyotyping data indicate a considerableamount of diversity exists wi th in sectionArachis species. For species outside sectionArachis, the genomes are not cytologically veri-f ied nor completely identif ied. Many questionspertaining to chromosome pair ing in hybr ids,causes for incompatibi l i t ies (failures of hybr idsmay be due in part to single genes condi t ioninggametophyt ic or sporophyt ic incompatibi l i t ies),and further biosystematic analyses to identifyaddit ional viable hybrids wi l l add considerablyto the understanding of species relationships.

Progenitor species of A. hypogaea are as yetunident i f ied. Present indications are that thecult ivated species combines the A and B genomes. However, only after extensivecytological analyses wi l l questions of ancestrybe clarif ied. Identifying progenitors of A.hypogaea is more than an academic question inthe genus. If progenitor species were used ininterspecific hybrid combinat ions, then pair ingand gene exchange wou ld be more likely tooccur. For example, if 4x amphid ip lo id hybridswere crossed w i t h the cult ivated species, andone of the species was an ancestor of A.hypogaea, then pair ing between the cult ivatedand w i ld species wou ld more likely occuramong all chromosomes in the trispecific hy-br id.

Cytogenet ic i n fo rma t ion has steadi ly ac-cumula ted du r i ng the past 40 years. Manyspecies still need to be collected and also suchbasic informat ion as chromosome numbers re-co rded . For the cu l t i va ted and a f ew w i l dspecies, especially in section Arachis, the usefulcytogenetic information wil l soon help in mani-pulating chromosomes for improvement ofpeanut varieties.

References

ASHRI, A., OFFENBACH, R., CAHANER, A., and LEVY, A.

1977. Transmission of acriflavin induced trisomicmutants affecting branching pattern in peanuts, A hypogaea L. Zeitschrift fur Pflanzenzuch 79: 220-228.

BABU, C. N. 1955. Cytogenetical investigations ongroundnuts. I. The somatic chromosomes. IndianJournal of Agricultural Science 25: 41-46.

79

BADAMI , V. K. 1928. Ph.D. thesis (unpubl ished). Uni -versi ty of Cambr idge, England. Cited in H. Huntedand H. M. Leake, 1933. Recent Advances in Agr icu l -tural Plant Breeding, Blakiston, Philadelphia.

C O N A G I N , C. H. T. M. 1963. Numero de c romosomasdas especies se l vagems de Arachis. Bragant ia22: 125-129 .

D ' C R U Z and TANKASALE, M. P. 1961. A note on ch romo-some complement of four groundnut varieties. IndianOilseeds Journa l 5: 58 -59 .

FERNANDEZ, A. 1973. El acido lact ico c o m o f i jadorc romosomico . Bo l . Soc. Argent . Bot. 15: 287 -290 .

G M I M P U , V. 1930. Recharches cyto log iques sur lesgenes: Hordeum, Acacia, Medicago, Vitis et Quer-cus. A rch . D'Anat. Microsc. 26: 136-234.

GIBBONS, R.W., and TURLEY, A. C. 1967. Grain legumepatho logy research team. Botany and Plant Breed-ing. Pages 8 6 - 9 0 in Annua l Report of the Agr icu l -tura l Research Counci l of Central Afr ica.

GREGORY, M. P., and GREGORY, W. C. 1979. Exotic

germplasm of Arachis L. interspecific hybrids. Jour-nal of Heredity 70: 185-193.

GREGORY, W. C. 1946. Peanut breeding program un-de rway . Pages 4 2 - 4 4 / n Research and Farming, 69thAnnua l Report , Nor th Carol ina Agr icu l tura l Experi-ment Stat ion.

GREGORY, W. C, GREGORY, M. P., KRAPOVICKAS, A.,

S M I T H , B. W., and YARBROUGH, J . A. 1973. Structures

and genet ic resources of peanuts . Chapter 3 inPeanuts — cul ture and uses. Amer ican Peanut Re-search and Educat ional Associat ion, St i l lwater, Ok-lahoma 74074 USA.

GREGORY, W. C, KRAPOVICKAS, A., and GREGORY, M. P.

1980. Structure, var ia t ion, evo lu t ion, and classifica-t ion in Arachis. Pages 4 6 9 - 4 8 1 in Summer f ie ld andBunt ing (eds.), Advances in Legume Science.

H U S T E D , L. 1931. Ch romosome numbers in species ofpeanut Arachis. Amer ican Natural ist 65: 476 -477 .

H U S T E D , L. 1933. Cytological studies of the peanutArachis I . Ch romosome number and morpho logy .Cytologia 5: 109-117 .

H U S T E D , L. 1936. Cytological studies of the peanutArachis II. Ch romosome number , mo rpho logy andbehavior and the i r appl icat ion to t he or ig in o f cul t i -vated f o rms . Cytotogla 7 : 396 -423 .

K A W A K A M I , J. 1930. Chromosome numbers in Legu-

minosae. Botanical Magazine (Tokyo) 44: 319-328.

K R A P O V I C K A S , A. , a n d R I G O N I , V . A . 1949.

Chromosomas de una especies s i lves t rede Aachis.Idia Buenos Aires 2: 2 3 - 2 4 .

KRAPOVICKAS, A., and R IGONI , V. A. 1957. Nuevas es-

pecies de Arachis v incu ladas al p rob lem del or igendel man i . Darwin ians 11 : 431 -455 .

KRAPOVICKAS, A., and GREGORY, W. C. 1960. Arachis

r igoni i nueva especie silvestre de mani . Revista deinvest igaciones Agr icolas Buenos Aires 14: 1 5 7 -160.

KRAPOVICKAS, A. , FERNANDEZ, A., and S E E L I G M A N , P.

1974. Recuperacion de la fert l l ldad en un h ibr idointerspecif ico esteril de Arachis (Leguminosae)Bonplandla 3: 129-142 .

M A D H A V A M E N O N , P., R A M A N , V . S., and KRISHNASWAMI ,

S. 1970. An x-ray induced monosomlc in groundnut .Madras Agr icu l tura l Journa l 57: 8 0 - 8 2 .

M E N D E S , A. J . T . 1947. Estudos c i to log icos no generoArachis. Bragantia 7: 257 -267 .

PATIU, S. H. 1968. Cytogenet ics of x-ray inducedaneuploids in Arachis hypogaea L. Canadian Jour -nal of Genetics and Cyto logy 10: 545-550.

PATIL , S. H., and BORA, K. C. 1961. Meiot ic abnor-mal i t ies induced by x-rays in Arachis hypogaea. In-dian Journa l o f Genetics 2 1 : 5 9 - 7 4 .

R A M A N , V. S. 1959. Studies in the genus Arachis VII. A natural interspecif ic hybr id . Indian Oilseeds Journal3: 226 -228 .

R A M A N , V. S. 1976. Cytogenet ics and breeding inArachis. Today and Tomor row ' s Printers and Pub-l ishers, New Delhi , India, 84 pages.

R A M A N , V. S., and KESAVAN, P. C. 1962. Studies on a

dip lo id interspecif ic hybr id in Arachis. Nucleus (Cal-cutta) 5: 123-126.

RESSLAR, P. M., and GREGORY, W. C. 1979. A cytological

study o f th ree d ip lo id species of the genus Arachis L..Journa l of Heredity 70: 13 -16 .

S I M P S O N , C. E. 1976. Peanut b reed ing strategy toexp lo i t sources of var iab i l i t y f r o m w i l d Arachis species. Proceedings of the Amer ican Peanut Re-search and Education Associat ion 8: 87 (Abs.).

S M A R T T , J . 1965. Cross-compat ib i l i ty re lat ionships be-tween the cul t ivated peanut Arachis hypogaea L.and other species of t hegenus Arachis. Ph.D. thesis,Nor th Carol ina State Univers i ty. No. 65,8968. Uni -

8 0

versi ty Mic ro f i lms Internat ional , Ann Arbor , Mich i -gan , USA.

SMARTT, J. 1979. Interspecific hybridization in the grainlegumes — A review. Economic Botany. 33: 3 2 9 -337.

SMARTT, J . , and GREGORY, W. C. 1967. Interspecific

cross-compat ib i l i ty between the cult ivated peanutArachis hypogaea L and other members of thegenus Arachis. Oleagineux 22: 455 -459 .

S M A R T T , J . , G REGORY, W. C, and GREGORY, M. P. 1978a.

The genomes oft Arachis hypogaea L.I. Cytogenet ics tud ies o f pu ta t i ve g e n o m e dono rs . Euphy t i ca27: 665 -675 .

S MARTT, J . , G REGORY, W. C, and G REGORY, M. P. 1978b.

The genomes of Arachis hypogaea. 2. The impl ica-t ions in interspecif ic breeding. Euphyt ica 27: 6 7 7 -680.

S P I E L M A N , F. V., BURGE, A. P., and Moss , J. P. 1979.

C h r o m o s o m e loss and me io t i c behav io r in in -terspecif ic hybr ids in the genus/lrac/7/s L. and theirimpl icat ions in breeding fo r disease resistance. 2.Pflanzenzuchtg 83: 236-250.

STALKER, H. T. 1978. Cytological analysis of Erec-toides x Arachis intersectional hybr ids. Proceed-ings of the Amer ican Peanut Research and Educa-t ion Associat ion 10: 62.

STALKER, H. T. No date. Intersectional hybr ids in thegenus Arachis between sections Erectoides andArachis. Crop Science (in review).

STALKER, H. T., and DALMACIO, R. NO date. Chromo-s o m e s of Arachis spec ies , s e c t i o n Arachis (Leguminosae). Journal of Heredity (in review).

STALKER, H. T., and W Y N N E , J. C. 1979. Cytology of

interspecific hybrids in section Arachis of peanuts.Peanut Science 6: 110-114.

STALKER, H. T., W Y N N E , J . C, and COMPANY, M. 1979.

Variat ion in progenies of an Arachis hypogaea x d ip lo id w i ld species hybr id . Euphytica 28: 675 -684 .

V A R I S A I M U H A M M A D , S. 1973a. Cytogenetical investiga-tions in the genus Arachis L. I. Interspecific hy-brids between diploids. Madras Agricultural Journal60: 323-327.

V A R I S A I M U H A M M A D , S. 1973b. Cytogenetical investi-gat ions in the genus Arachis L. II. Tr ip lo id hybr idsand their derivat ives. Madras Agr icul tural Journal60: 1414-1427.

VARISA I M U H A M M A D , S. 1973c. Cytogenetical investi-gat ions in the genus Arachis L. III. Tetraplo id in-terspecif ic hybr ids and their derivatives. MadrasAgr icu l tura l Journal 60: 1428-1432.

81

Utilization of Wild Arachis Species at ICRISAT

A. K. Singh, D. C. Sastri and J. P. Moss*

One of the possibi l i t ies for increasing the yieldof g roundnu t , par t icu lar ly in the Semi-Ar idTropics, is breeding varieties w i t h resistance topests and diseases. Some progress has beenmade in this f ie ld, but the improvements thatcan be made by breeders are l imited by theavailabil i ty of genes w i th in A. hypogaea. Collec-t ions of w i ld species f rom South Amer ica havemade avai lable a wider range of genes, espe-cially genes for disease resistance. The richnessof Arachis germplasm col lect ion offers a greatoppor tun i ty for anyone interested in the im-provement of this crop (Bunt ing et al. 1974,Simpson 1976; Smartt et a I. 1978a, b; Gregoryand Gregory 1979).

However the cy to taxonomy of the genusArachis is such that it is diff icult for a breeder touse w i ld species in groundnut improvement(Gregory and Gregory 1979; Moss 1980; Stalker1980). The two major constraints to uti l izationof w i l d species are differences in ploidy leveland incompat ib i l i ty between some wi ld speciesand A. hypogaea. The small size of chromo-somes of Arachis and the dif f iculty experiencedby some workers in making good cytologicalpreparations has deterred many people f romattempt ing cytogenetic techniques in the im-provement of Arachis, despite their successfulappl ication to many other crop plants, espe-c ia l ly w h e a t and tobacco . The g r o u n d n u tcytogenetics program at ICRISAT has at temp-ted to overcome these dif f icult ies, and to pro-duce interspecific hybr ids and to manipulatethe ploidy level to produce tetraploid lines in-corpora t ing desi rable characters wh ich canthen be util ized by breeders in the improvementof groundnut .

The program on uti l ization of w i ld species inArachis was in i t iated at Reading Univers i ty(U.K.) w i t h three species wh ich were known tocross w i t h A. hypogaea and were resistant to

* Cytogeneticists, Groundnut Improvement

g r a m , ICRISAT.

Pro-

leaf spots. These were A. cardenasii Krap. andGreg., nomen nudum, A. chacoense Krap. andGreg., nomen nudum, and Arachis species Coll.HLK 410 wh ich were reported as immune toCercosporidium personatum, h ighly resistantto Cercospora arachidicola, and resistant toboth (Abdou 1966; Sharief 1972; Abdou et al.1974; Hammons, personal communicat ion).

The groundnut cytogenetics program atICRISAT was init iated in Apr i l 1978 w i th theobject of making the fullest possible use of thegenus Arachis. Cooperat ion w i th the GeneticResources Unit, pathologists, entomologists,and microbiologists has increased the numberof wi ld species at ICRISAT and our knowledgeof the desirable genes which they contain.Cytogenetic analysis provides informat ion toimprove the efficiency of incorporat ion of w i ldspecies genes into A. hypogaea. Thetechniqueshave been described by Singh et al. (1980).

In addi t ion to A. hypogaea, section Arachis contains one other tetraplo id. A. monticola, andseveral d ip lo id species. All these species arecross compat ib le w i th A. hypogaea (Smartt andGregory 1967; Stalker 1980). N ine d ip lo idspecies and the t w o te t rap lo ids have beenstudied in detail and a ch romosome wi th a sec-ondary constr ict ion and a small satell ite seen aschromosome 3 in A. villosa, A. correntina, A.chacoense, and Arachis species Coll. No. 10038,and a chromosome wi th a secondary constric-t ion and a large satellite seen in A. batizocoi andin A. duranensis as chromosome 2, in Arachis species 338280 as chromosome 6 and in A cardenasii as chromosome 9. Chromosomeswi th secondary constr ict ions had only beenreported previously in A. batizocoi. The smallpair of chromosomes in A. cardenasii are largerthan in the remaining species but still smallerthan the smallest chromosomes of A. batizocoi. A. monticola and A. hypogaea are closekaryomorphological ly , though A. monticola hast w o pairs of chromosomes w i t h secondaryconstrict ions whereas A. hypogaea has onlyone, and the chromosome wi th a secondary

82

constr ict ion in A. cardenasii is comparable toone of those of A. monticola and that of A.hypogaea.

M a h a l a n o b i s D 2 ana lys is and canon ica lanalysis, using the arm ratio of each of the tenchromosomes of the diploid taxa investigated,resulted in two clusters w i th in these. A.batizocoi is the only species in one of theseclusters; there are eight taxa in the other cluster,wh ich can be further subdivided (Fig. 1).

Al l the species of the section Arachis arecross-compatible, and differences in crossabi-lity are too small to be satistically significant. Allthe available nine diploid taxa have been cros-sed in all possible combinat ions and a largenumber of F1 hyb r ids have been analysedcytological ly. Results f rom these studies sub-stantiate our grouping of the diploid species.The F1 hybr ids result ing f r om the cross of twospecies belonging to the two dif ferent clustersshow a high frequency of univalents and a highpollen steril i ty, wh i le F1 hybr ids between twospecies of the same cluster show a low f re -quency of univalents and a low pollen steril ity.

D2 distances among species of section Arachis

These basic studies are designed to assist usin the main objective of the cytogenetics unit,i.e., the uti l ization of the w i ld species for theimprovement of groundnuts. The two go handin hand because m a n y o f t he p lants p ro -duced in the course of uti l ization of w i ld speciesare analyzed in detai l , and plants which areanalyzed are then used in crossing programs.The two main thrusts of the subprogram are theuse of compat ib le species to transfer currentlyavailable genes, and the study of the barriers tohybridization and the means of breaking themto make the whole gene pool wi th in Arachis available to breeders in the future.

B r e e d i n g i n C o m p a t i b l e S p e c i e s

The incorporat ion of genes f rom wi ld speciesinvo lves the t ransfer o f one or m o r e w i l dspecies genomes to a hybrid where they canu n d e r g o r e c o m b i n a t i o n w i t h A. hypogaea genomes, and subsequent transfer of the de-sired gene or genes into A. hypogaea w i th theel iminat ion of all undesirable characters f romthe w i ld species. Five routes have been adoptedto achieve these objectives (Fig. 2).

Trip lo id Route

Smart t and Gregory (1967), Moss and Spielman(1976), Raman (1976), and Moss (1977) have allproduced hexaploids by chromosome doubl ingin a tr ip loid hybr id. As early as 1976, ICRISATreceived hexaploids f rom the program at Read-ing University. These hexaploids combined thegenomes of A. cardenasii, A. chacoense andArachis species No. 338280 w i th A. hypogaea, and were screened for leaf spot resistance atICRISAT, which is mainly infested by late leafspot (C. personatum). Resistant plants wereselected f rom each type of hexaploid, and havebeen backcrossed to different cultivars of A.hypogaea (Moss 1980). These progenies arenow in the four th generat ion of backcrossingand tetraploid and near tetraploid plants arebeing screened for disease resistance. Manyhexaploids were also resistant to rust. There isno correlat ion between leaf spot or rust resis-tance and defol iat ion in hexaploids der ivedf rom resistant w i ld species, as some hexaploidssusceptible to disease do not defoliate. Con-versely, some hexaploids w i th f ew small le-sions suffer severe defo l ia t ion (Moss et al .

83

A. villosa

A. correntina

A. chacoense

A. sp 263133

(SL)

A. sp 263133(LL)

A. sp 338280

A. duranensis

D 2 =0.99 A. batizocoi

D2= 0 .379 -0 .883

A. cardenasii

Cluster I Cluster II

Average intracluster D 2= 0.335

Figure 1. Cluster diagram.

GENOME TRANSFER GENE TRANSFER

1979). The fe r t i l i t y o f t h e hexap lo i ds andbackcrosses ranges f r om ni l , in some sterile butvegetatively v igorous plants, to highly produc-t ive. Some plants produce many pegs per nodeand pegs per plant, but few pods, whi ls t othershave good reproductive efficiency.

Crosses between A. hypogaea and f ive dip-loid species have produced 92 pods (Table 1).Five t r ip lo ids have been established f r om spr-outs and the remaining seed wi l l be used toproduce hexaploids.

The artif icial induct ion of po lyp lo idy in a tr ip-loid to restore fert i l i ty, can be dif f icult and t imeconsuming, so the development of a techniquewhereby large numbers of cutt ings of the sterilet r ip lo id can be treated has increased the pro-duct ion of hexaplo ids (Spie lman and Moss1976; Nigam et al. 1978). Tr ip lo ids can producefert i le gametes th rough the format ion of a re-st i tut ion nucleus and by segregation g iv ing 2nor near 2n gametes. Studies of Anaphase I ofmeiosis show that 30, 20 and hyper-20 ch romo-some cells occurred; t r ip lo ids have producedseed in the f ield at ICRISAT.

This process may be environmental and/orgenotype specif ic; fo r instance high tempera-ture in India may be one of the reasons for theformat ion of unreduced gametes, and the t r ip-loids differ in the frequency w i t h wh ich theyproduce seed. This latter may be due to thedifferent w i l d species used, or an effect of thedi f ferent A. hypogaea genotypes wh ich areknown to affect the amount of pair ing in hexa-ploids (Spielman et al. 1979).

Auto te t rap lo id Route

The product ion of an autotetraploid f r om a dip-loid w i ld species enables all hybr idizat ion andgenome transfer to be done at the tetraploidlevel, and increases the dosage of w i ld speciesgenes. Autotetraplo ids have been produced inseven taxa (Table 2). Of these only A. batizocoi (4x) has produced seed; many plants of theothers remained sterile and eventually d ied.However, three autotetraploids were success-ful ly used as male parents in crosses w i th A.hypogaea (Table 3). The resultant progenies aremorphological ly similar to A. hypogaea, butcytological ly unstable, and sterile. A number ofgenerat ions of self ing of the autotetraploids wi l lincrease the frequency of balanced gametes,and the l ikel ihood of fert i le hybr ids w i th A.hypogaea. Hybrids wi l l be backcrossed to A.hypogaea to restore fert i l i ty whi ls t selecting de-sirable recombinants.

Amph ip lo id Route

Chromosomedoub l ing in a hybr id between t w odip lo id w i ld species produces an amphid ip lo idwhich combines the two w i ld species, wh ich ist hesame ploidy level as tetraploid A. hypogaea, and increases the number of genomes in thehybr id and therefore the number of possiblerecombinants. I f the two w i ld species used arethe ancestors of A. hypogaea, the amphid ip lo idwi l l be a synthetic A. hypogaea, and th is may bethe most promis ing tetraplo id derivat ive of the

84

Figure 2. Utilization of diploid and tetraploid wild species.

Reciprocalbackcrossingw i thA. hypogaea

6X

5 X - 6 X

4X

4X

4X Cult.

4X

3X Chromosomedoub l ing

3X

4X

4X Cult.

2X Chromosome.doubl ing

4X Cult.

2X Wi ld(4) 4X Wi ld

(3) 2 x W i ld

doubl ing

2X Wi ld(2) 2X Wi ld Chromosome

2X Wi ld(1b) 4 X Cult.

(1a) 4X Cult.

Tab le 1. Crossab i l i t y b e t w e e n A. Hypogaea and d ip lo id species of sec t ion Arac his.

CrossNo. of

Pol l inat ionsNo. /%

of pegsNo . /%

of pods

A. hypogaea x A. correntina A. hypogaea x A. batizocoi A. hypogaea x A. villosa A. hypogaea x A. duranensis A. hypogaea x A. sp 338280

6364875844

24/3820/3138/4419/3315/34

22*/3516/2526/3014*/2414/32

Total 316 116/37 92/29

* Sprouts p roduced.

wi ld species wi th regard to the genetic im-provement of A. hypogaea. Intracluster crossesare much more successful than interclustercrosses (Fig. 3).

Fifty-one amphip lo ids have been raised f rom17 different cross combinat ions of w i ld species,including A. batizocoi (Table 4), and eight dif fe-rent combinat ions have been successfully cros-sed w i th A. hypogaea (Table 5). The resultantprogenies are being analyzed morphological ly

and cytological ly; their behavior is similar tothe progenies obtained through the autotetrap-loid route. The amphiplo ids involv ing threespecies are the most fert i le.

Use of Tet rap lo id Wi ld Species

A. monticola has been crossed w i th A.hypogaea and ful ly fert i le hybrids have beenproduced.

85

Tab le 2 . P roduc t i on o f au to te t r ap l o i ds f r o m w i l d d ip lo id Arachis species.

SpeciesSeedl ings

treatedPlants

surv ived2x

plants4x

plants

A. villosa 17 14 11 4A. correntina 18 16 10 2A. chacoense 5 1A. sp 338280 19 12 3 3A. sp 263133 8 5 4 1A. duranensis 7 6 2 2A. cardenasii 15 14 1 3A. batizocoi 26 21 11 10

Tab le 3. Crossabi l i ty b e t w e e n A. hypogaea and au to te t rap lo ids of sect ion Arachis.

CrossNo. of

pol l inat ions

No. /%of pegs

No. /%of pods

A. hypogaea x A. sp 338280 (4x)A. hypogaea x A. villosa (4x)A. hypogaea x A. sp 263133 (4x)

132139113

384

16/1230/2219/17

13*/1020*/1417/15

Total

132139113

384 65/17 50/13

* Sprouts p r o d u c e d .

Figure 3. Percentages of peglpod production in interspecific crosses in section Arachis.

Gene Transfer

By Chromosome Pairing

Our cytological analysis of the diploid wildspecies, F1 hybrids and triploids resulting fromcrosses of wild diploid species with A hypogaea has indicated that there is chromo-some homology or homoeology among thegenomes of all the wild diploid species studiedand between these genomes and A hypogaea.

This means that there is a good probability ofgene transfer through chromosome pairing inthese hybrids and backcrosses producing newgene combinations in progenies, enablingselection of the desired plants.

Induced Translocation

Such chromosome pairing may not alwaysoccur, either because of the incorporation of a nonhomologous genome, or because the gene-tic background of the hybrid prevents pairing ofhomologous genomes. In such cases transloca-tion of chromosome segments has to be in-duced through mutagenesis.

Barriers to Hybridizationand Means of Breaking ThemA hypogaea has not been successfully andrepeatably crossed with any species outsidesection Arachis (Gregory and Gregory 1979).Many species in other sections have pot-ential as gene sources in groundnut im-provement (Moss 1980). Tetraploid wild speciesare found in section Rhizomatosae (Gregoryand Gregory 1979) and these species are ofspecial interest as they are immune to manypathogens. Several attempts have been madeby many people over the years to achieve anintersectional hybrid but these have not beensuccessful (Gregory and Gregory 1979). Recentadvances in the knowledge of the physiologyand development of pollen, factors involved inpollination and advances in the technology of

86

Table 4. Number of amphiploids established in section Arachis.

A

corr

entin

a

A s

p 3

3828

0

A

dura

nens

is

A.

sp 2

6313

3

A

chac

oens

e

A.

chac

oens

e x

A.

card

enas

ii

A villosa 6 2A. correntina 4 1 5A sp 338280 2 2A. duranensis 1 1 3 5A. sp 263133 2 3A. batizocoi 2 1 8

A. villosa

A. correntina

A. chacoense

A. sp 338280

A. sp 263133 (LL)

A. sp 263133 (SL)

A. duranensis

A. batizocoi

A. cardenasii

Total no. of pol l inat ionsTotal no. of pegsTotal no. of pods

53481453901

27/16

Table 5. Crossabllity batween A. hypogaea and amphlploids.

tissue culture have increased the possibility ofproducing hybrids between species which werepreviously considered to be genetically isolated(Heslop Harrison 1978; Vasil 1978, 1980;Shivanna et al. 1979; Sala et al. 1980).

In June 1979 a project was initiated to investi-gate the barriers to intersectional hybridization.Fluorescent microscopic comparison of thecompatibly and incompatibly pollinated pistilsshowed that in the former, the pollen tubes

were smooth with small callose patches distri-buted evenly along the lengths of the pollentubes. In the incompatibly pollinated pistils,however, the callose depositions along thepollen tube were uneven and in larger quan-tities indicating a retarded growth of the tubes.However, a small frequency of incompatiblepollinations induced peg initiation and elonga-tion, though these usually dried and degener-ated before they penetrated the soil.

87

CrossNo. of

pollinationsNo./%

of pegsNo./%

of pods

A. hypogaea X

[A. correntina

A. hypogaea X

[A. correntina X

[A chacoense x A. cardenasii)] 160 26/16 22*/14

A. hypogaea

X[A. sp. 338280

X

(A. chacoense x A. cardenasii)] 164 42/26 32*720

A. hypogaea X

{A. correntina x A. villosa) 199 62/31 42*721

A, hypogaea X

{A. villosa x A. sp 338280)135 15/11 15*/11

A. hypogaea X

(A duranensis x A. chacoense) 96 9/9 7»/7

A. hypogaea X

(A batizocoi x A. villosa) 29 8/28 7/24

A. hypogaea X

(A batizocoi x A. duranensis) 18 7/39 5*/28

A. hypogaea X

[A. batizocoi x A. chacoense) 10 7/70 3*/30

Total 811 176/22 133/16

* Sprouts produced.

A number of techniques have been tested fortheir efficiency to overcome such incompatibili-ty. Plant growth hormones applied to the ovarywere found to increase the frequency of pegformation in incompatible crosses. The initialtrials, using cytokinin at 10-6M applied to cottonwebs wrapped round the ovaries, were fol-lowed by trials using four concentrations ofkinetin and three of benzylamino purine, as wellas auxins and gibberellic acid. The effects ofthese treatments are shown in Table 6. Kinetin,naphthaleneacetic acid and gibberellic acid haveall significantly increased the pegging percen-tage.

Some of these pegs have been left to formpods in the soil. Others have been excised fromthe plants for aseptic culture of the tip of thepeg, or the ovule, or the embryo. We have so farbeen able to culture immature embryos suc-cessfully into seedlings using Murashige andSkookg's 1962 medium. Our attempts to culturepegs according to Ziv and Zamsky (1975), orovules according to Martin (1970), even fromcompatible crosses, have not given satisfactory

repeatable results. We were able to inducenormal embryogeny in one ovule culture up tothe cotyledonary stage of the embryo by usingan aqueous peg extract in the medium.

While excising the embryos from seed forculture, the cotyledons were also cultured. Weobserved that the end of the cotyledon proximalto the embryo is a highly embryogenic tissuewhich gives rise to roots, shoots, embryoids orwhole plants depending upon the hormonalbalance in the medium. We have also beentrying to regenerate plants from leaflet seg-ments and have been able to induce roots butnot shoots or embryos, although we have triedfour different basic media, White (1943),Murashige and Skoog (1962), Gamborg et al.(1972) and Kao and Mickayluk (1975), with a range of auxins and kinetins, as well as supple-menting with coconut milk, casein hydrolysate,yeast extract, malt extract or gibberellic acid.

Conclusion

Considerable progress has been made with a

Table 6. Effact of soma plant growth hormones on pegging afte r pollination of tetraploid speciesof section Anchls with Arachis sp PI No. 276233 of section Rhizomatotae.

Arachis monticola A. hypogaea var . Robut33-1

No. of Pegs formed No. of Pegs formedCross Treatment pollinations (%) pollinations (%)

Compatible None 201 34.33 156 34.62(self)

Incompatible None 314 17.20 147 15.65(control)

Incompatible Kinetin, 10-4 M 21 14.29

" Kinetin, 10-5 M 90 15.56 82 25.00" Kinetin, 10-6 M 75 18.67 55 25.46It Kinetin, 10-7 M 95 14.75 87 40.23" Benzyl Adenine, 10-5M 134 22.39" Benzyl Adenine, 10-6M 191 20.42" Benzyl Adenine, 10-7M 98 19.39" Indole Acetic Acid 107 13.08 53 24.53" (25 ppm)» Napthalene Acetic Acid

(25 ppm)129 17.83 52 42.31

" 2, 4-Dlchloro Phenoxy-acetlc Acid (25 ppm)

73 17.81 18 22.22

* Gibberellic Acid(25 ppm)

37 48.65

" Kinetin 70-4M + Indole Acetic Acid (25 ppm)

89 24.72

88

number of different ways of utilizing wi ld species.The number of plants produced, and the rangeof variat ion they show, indicate that there isgood potential for transferring desirable charac-ters f r om wi ld species. A l though the wi ldspecies were original ly considered solely assources of disease resistance, the progeniesf rom interspecific crosses have potential as a means of expanding the gene pool of Arachis wi th respect to a number of other desirablecharacters.

Results of attempts to break the barriers tohybridization hold promise for utilization ofcharacters f r om species outs ide sectionArachis.

References

ABDOU, Y. A. M. 1966. Ph.D. Thesis, North CarolinaState Univ., Raleigh, USA.

ABDOU, Y. A. M., GREGORY, W. C, and COOPER, W. C.

1974. Sources and nature of resistance to Cercos-pora arachidicola Hori and Cercosporidium per-sonatum (Beck and Curtis) Deighton in Arachis species. Peanut Science 1: 6 -11 .

BUNTING, A. H., GREGORY, W. C, MAUBOUSSIN, J. C,

and RYAN, J. G. 1974. A proposal for research ongroundnuts {Arachis) by ICRISAT. ICRISAT Mimeo.ICRISAT, Patancheru, A. P. 502 324, India.

GAMBORG, O. L, MILLER, R. A., and OJIMA, K. 1968.

Nutrient requirements of suspension cultures ofsoybean root cells. Experimental Cell Research50: 151-158.

GREGORY, M. P., and GREGORY, W. C. 1979. Exotic

germplasm of Arachis L. Interspecific hybrids. Jour-nal of Heredity 70: 185-193.

HESLOP-H ARRISON, J. 1978. Genetics and physiology ofangiosperm incompatibility systems. Pages 73-92in Proceedings of the Royal Society, London. 202 B.

MARTIN, J. P. 1970. Culture in vitro d'ovules Arachide. Oleagineux 253: 55-56.

Moss, J. P. 1977. Cercospora resistance of in-terspecific Arachis hybrids. Proceedings of theAmerican Peanut Research and Education Associa-tion 9: 34 (Abs.).

Moss, J. P. 1980. Wild species in the improvement ofgroundnuts. Pages 525-535 in Advances in legumescience (eds. Summerfield and Bunting),Vol. 1, Pro-

ceedings of the International Legume Conference,Kew, England, 1978.

Moss, J. P., and SPIELMAN, I. V. 1976. Interspecifichybridization in Arachis. Proceedings of the Ameri-can Peanut Research and Education Association8: 88 (Abs.).

Moss, J. P., SINGH, A. K., BURGE, A. P., and BRADLEY, S.

1979. Wild species in the improvement ofgroundnuts. 1, Disease reaction of hexaploids. Pro-ceedings of the American Peanut Research andEducation Association 11: 55 (Abs.).

MURASHIGE, T., and SKOOG., F. 1962. A revised

medium for rapid growth and bioassays with to-bacco tissue cultures. Physiologic Plantarum15: 473-497.

NIGAM, S. N., Moss, J. P., and GIBBONS, R. W. 1978.

Vegetative propagation oi Arachis species. ICRISATMimeo. ICRISAT, Patancheru, A. P. 502 324, India.

RAMAN, V. S. 1976. Cytogenetics and breeding inArachis. Today and Tomorrow's Printers and Pub-lishers, New Delhi, India.

RAO, K. N., and MICHAYLUK, M. R. 1975. Nutritionalrequirement for growth of Vicia hajastana cells andprotoplasts at a very low population density in a liquid media. Planta 126: 105-110.

SALA, F., PARIS, B.,CELLA, R., and CIFERRI, 0.1980. Plant

cell culture: results and perspectives. Elsevier-North Holland Biomedical Press, Holland.

SHARIEF, Y. 1972. Ph.D. Thesis, North Carolina StateUniv., Raleigh, U.S.A.

SHIVANNA, K. R., JOHRI, B. M., and SASTRI, D. C. 1979.

Development and physiology of ang iosperm pollen.Today and Tomorrow's Printers and Publishers.New Delhi, India.

SIMPSON, C. E. 1976. Peanut breeding to exploit sourceof variability from wild Arachis species. Proceedingsof the American Peanut Research and EducationAssociation 8: 87 (Abs.).

SINGH, A. K., Moss, J. P., and SASTRI, D. C. 1980. Utili-zation of wild relatives in genetic improvement ofArachis hypogaea: Techniques. Proceedings AllIndia Seminar on Current Methodological Ap-proaches in Cytogenetics, Centre of Special Assis-tance in Cytogenetics, Patna University, India.

SMARTT, J., and GREGORY, W. C. 1967. Interspecific

cross-compatibility between the cultivated peanutArachis hypogaea L. and other members of genusArachis. Oleagineux 22: 455-459.

89

SMARTT, J . ,GREGORY,W.C , and GREGORY,M.P. 1978a.

The genomes of Arachis hypogaea L. 1. Cytogeneticstudies of putative genome donors. Euphytica27: 665-675.

S MAUTT, J., G REGORY, W. C, and G REGORY, M. P. 1978b.

The genomes of Arachis hypogaea. 2. The implica-tions in interspecific breeding. Euphytica 27: 667-680.

SPIELMAN, I. V., and Moss, J. P. 1976. Techniques forchromosome doubling in interspecific hybrids inArachis. Oleagineux 31: 491-494.

SPIELMAN, I. V., BURGE, A. P., and Moss, J. P. 1979.

Chromosome loss and meiotic behaviour in in-terspecific hybrids in the genus Arachis L. and theirimplications in breeding for disease resistance.Zeitschrift fur Pflanzenzuchtung 83: 236-250.

STALKER, H. T., 1980. Cytogenetic investigations in thegenus Arachis. Proceedings this workshop.

VASIL, I. K. (ed.). 1980. Perspectives in plant cell andtissue cultures. International review of cytology,Supplement 11, Parts A and B. Academic Press, NewYork, USA.

VASIL, I. K., AHUJA, M. R., and VASIL, V. 1979. Plant

tissue cultures in genetics and plant breeding. Ad-vances in Genetics 47: 127-216.

WHITE, P. R. 1943. A handbook of plant tissue culture.J. Catell Press, Lancaster.

Ziv, M., and ZAMSKI, E. 1975. Geotropic responses andpod development in gynophore explants of peanutArachis hypogaea cultured in vitro. Annals ofBotany 39: 579-583.

90

Session 4 — Cytogenetics and Utilization of WildSpecies

Discussion

C. Raja ReddyThe cytology and pollen fertility of the hybridbetween A. villosa xA correntina point totheir close similarity, which is also substan-tiated by the D2 analysis. In view of this, is theseparation of the two species into distinctones justified?

H. T. StalkerThe two species are recognized in taxonomybased on the differences in external morphol-ogy. In fact, most species of Arachis aredelineated from considerations of morpholog-ical differences. A biosystematic classificationof the species of Arachis is no doubt desirable,but this has to wait till an extensive study oftheir cytogenetics is carried out.

K. S. LabanaHave any monosomicornullisomic lines beendeveloped in Arachis?

H. T. StalkerStudies on monosomic and nullisomic plantsin Arachis have been meager. The limitedinvestigations have shown their cytologicalinstability. The development of such lines inArachis will entail intensification of researchon this aspect.

P. S. ReddyMany methods of interspecific gene transfer-ence from the wild species of Arachis to thecultivated A. hypogaea are cited but not oneon development of haploid plants of A.hypogaea through pollen culture and utilizingsuch plants in hybridization with diploidspecies. Does this not appear to be a profitableapproach?

J. P. MossThe information on induction of haploidy in A.hypogaea through pollen culture gained fromstudies carried on in this country and

elsewhere are awaited.

U. R. MurtyAttempts at culturing the pollen of triploidhybrids between A. hypogaea and diploidspecies are likely to lead to the realization ofaneuploids.

A. K. SinghAlthough this route may not be very fruitful ontheoretical considerations, it is worth a trial.

R. W. GibbonsHexaploids generally suffer from low podyields. Has there been any attempt to study theprogeny behavior of the hexaploids from thisangle?

H. T. StalkerThe hexaploids have been found to be lowyielders. But exception to this generalizationhas also been noticed. In the case of theprogenies developed from the hexaploid of A hypogaea x A cardenasii, plants in the 9thgeneration showed an improvement in podyields comparable to that of cv NC-5.

R. 0. HammonsWould it be feasible to pursue cytogeneticresearch through the use of haploid plantsisolated from twin seedlings?

H. T. StalkerTwin seedlings from seeds of A hypogaea areknown to occur at a low frequency and thesewere found to be tetraploid in constitution.Efforts are under way to locate haploid seedl-ings from haploid-diploid twins.

J. P. MossExperience has shown that small andshriveled seeds have given aneuploids ratherthan haploids. The significance and impor-tance of haploids in cytogenetic analysis is

91

well-realized, and exercises to isolate haploidsare under way.

What is the basis of differentiation of thegenomes as A1, A2, and A3?

H. T. StalkerThe differentiation is based on the karyomor-phology of the species, nature of chromosomepairing in hybrids, and their levels of fertility.Such a genomic differentiation is only tenta-tive and more evidence has to be gathered toconfirm it.

C. Raja ReddyThe karyological features of nine diploidspecies have been taken into consideration forthe D2 analysis. A larger array of materialshould have been included in this analysis.

A. K. SinghThe necessity to draw more species of D2

analysis is recognized, and as and when addi-tions are made, the analysis will be continued

but not on a priority basis.

H. T. StalkerIn view of the importance attached tocytogenetic investigations of applied value,studies on D2 analysis may be left to bepursued by academic institutions rather thanby ICRISAT.

V. S. RamanLet me give my understanding of this D2

analysis that has been done with reference tonine diploid species. In group 1, eight speciesare accommodated and in group 2, A batizocoi stands out prominently. With refer-ence to the origin of A hypogaea as currentlyunderstood, A batizocoi is one of the parentsinvolved in the origin. So this analysis justifiesthe stand taken in the hypothesis that A batizocoi is one of thediploid parents involvedin the origin of the tetraploid. Even with thisanalysis, the piece of fundamental informa-tion can be drawn.

92

Session 5

Crop Nutrit ion and Agronomy

Chairman: A. Narayanan Rapporteurs: P. W. AminR. W. GibbonsV. K. Mohan

Increasing Nitrogen Fixation of the Groundnutby Strain and Host Selection

J. C. Wynne, G. H. Elkan and T.J. Schneoweis*

As the cost of nitrogen fertilizer derived fromfossilfuelscontinuestorise, biological nitrogenfixation will become more important for thecontinued productivity of agricultural crops. Inthe immediate future, successful increases inbiological nitrogen fixation most likely willcome from improvements in the symbioticfixation by legumes.

Groundnuts (Arachis hypogaea L), sincethey are grown on about 18 million hectares in82 countries, should contribute to the increasein dinitrogen fixed. Increases in dinitrogen fixedby groundnuts can be accomplished by theselection of more effective strains of Rhizobium and/or selection of more efficient host plants.

Selection of EffectiveStrains of Rhizobium

Groundnuts are a member of the cowpeacross-inoculation group. Rhizobia isolated froma diverse group of legumes are capable ofnodulating groundnuts (Burrill and Hansen1917; Walker 1928; Carroll 1934; Raju 1936;Mostafa and Mohmoud 1951; Berenyi 1962;Rajagopalan and Sadasivan 1964; Doku 1969;Gaur et al. 1974a). Not all rhizobial strains areequally effective in fixing nitrogen in symbiosiswith groundnuts (Allen and Allen 1940; Collins1943; Erdman 1943; Berenyi 1962; Denarie1968; Vidyasekaran et al. 1973; Dadarwal et al.

* Associate Professor of Crop Science, Professor andResearch Assistant of Microbiology, respectively,North Carolina State University, Raleigh, NorthCarolina, 27650, USA.

Note: Paper No. 6638 of the Journal Series of theNorth Carolina Agricultural Research Service.This research was partially supported bygrants USDA-SEA-CR 701-15-24 and 616-15-192 under A.I.D. PASA AG/TAB 610-9-76.

1974; Weaver 1974). Therefore, effective rhizo-bial strains should be identified and used toinoculate groundnuts to ensure an effectivesymbiosis (Erdman 1943; Schiffmann 1961;Schiffmann and Lobel 1970; Gaur et al. 1974a;Lopes et al. 1974; Weaver 1974; Burton 1976).However, to be useful, effective strains mustsurvive in and colonize the soil into which theyare introduced. Unfortunately many effectivestrains have been unable to survive andcolonize under field conditions (Schiffmann1961; Shimshi etal. 1967; Schiffmann and Alper1968b; Pant and Iswaran 1970; Gaur et al.1974b; Iswaran and Sen 1974; Kumara Rao etal.1974). Introduced strains which survive mustalso be able to compete for infection sites on theroot with less effective native strains. Fre-quently introduced strains are not very com-petitive (Berenyi 1962; Denarie 1968).

Significant responses to inoculation with ef-fective strains have largely been restricted tocontrolled conditions (Chomchalow 1971) andfield experiments on virgin groundnut soils(Duggar 1935b; Collins 1943; Schiffmann1961; Berenyi 1962; Shimshi et al. 1967;Schiffmann and Alper 1968a,b; Denarie 1968;Burton 1976). When inoculation with effectivestrains has been successful, the result has beenincreased yields of fruit, plant dry matter, nodu-lation, percentages of large fruits and seeds,and nitrogen content of foliage and seed.

The collection, identification, and use ofsuperior strains of rhizobia should be anintegral part of a groundnut research program.Inoculants produced from superior strains speci-fically tailored to the local environment shouldbe used where nodulation is not adequate forgood growth and high yields. These inoculantsshould also be used where nodulation appearsadequate but a growth response to nitrogenfertilizer is observed si nee this suggests that thestrains producing the nodules may not be effi-cient.

95

Nodule Collection, StrainIsolation, and MaintenanceStrains of Rhizobium for groundnuts are main-tained at several international and nationalcenters such as ICRISAT; USDA, Beltsville,Maryland, USA; and NifTAL, University ofHawaii, USA. Because of the limited research onthe groundnut-Rhizobium symbiosis, only a few of the available strains have been testedwith groundnuts. For example, the USDARhizobium culture collection catalog (1979)lists 16 strains for groundnuts of which onlyfour are recommended for symbiotic effective-ness. The NifTAL catalog (1978) recom-mends five strains and lists 11 additional strainsthat are effective with groundnuts.

Because of the limited number of recom-mended strains of Rhizobium and the lack ofknowledge about their performance in sym-biosis with the groundnut germplasm growth inNorth Carolina, we concluded that one of theprincipal goals of our program should be toisolate and identify effective rhizobial strains.

Initially we obtained strains of rhizobia fromother researchers. Additional strains ofRhizobium were isolated from nodules col-lected from centers of diversity for the genusArachis in South America. The nodules wereobtained from Arachis collecting expeditionssponsored by IBPGR and led by W. C. Gregory(North Carolina State University, Raleigh) andC. E. Simpson (Texas A & M University,Stephenville). After sampling, the nodules wereplaced in 7.5 ml plastic vials containing an-hydrous calcium chloride, covered with a cottonplug, and mailed to our laboratory in NorthCarolina. After the nodules were received fromSouth America, they were rehydrated in sterilewater for 4 hours at 5oC. They were thenaseptically dissected, and a nichrome wire wasused to streak some of the tissue on yeastextract mannitol agar in previously poured petriplates. Cultures were incubated at 28°C andexamined daily for raised mucoid colonies typi-cal of rhizobia. These colonies were restreakeduntil pure cultures were obtained. Using thesetechniques, 234 bacterial isolates representing78 germplasm collections were obtained fromnodules collected in 1976-77 (Tables 1,2). Addi-tional strains are now being isolated fromnodules collected in 1979 and the spring of1980.

The Rhizobium culture collection is main-

tained in screw-capped tubes containing yeastmannitol agar and stored at 5°C. These culturesare maintained in duplicate with one.set beingthe working collection. In addition to agarslants, the mother collection is also preservedon porcelain beads with silica gel and inlyophilized form. These latter two techniqueslimit loss of culture viability with minimal risk ofmutation or contamination. Transfers of thisRhizobium collection are provided upon re-quest to interested investigators. Additionalcowpea strains from the diverse environmentwhere groundnuts are grown need to be col-lected.

Evaluat ion of Ef fect ivenessof St ra ins

We use siratro (Macroptilium atropurpureum) for preliminary screening of isolates. This small-seeded legume is grown in the growth chamberin 30 ml serum bottles capped with plastic bags.The roots are examined for nodulation after 21days. Strains capable of nodulating siratro areincreased for testing with groundnuts. Thisfurther evaluation of these rhizobia is usuallycompleted in stages. We first test rhizobia in thegreenhouse with two host genotypes of diffe-rent origin. Those strains that are effective ingreenhouse studies must then be tested in thefield in competition with indigenous rhizobia.

Greenhouse Evaluat ion

Argentine (Spanish type) and NC-4 (Virginiatype), two cultivars representing the two sub-species of groundnuts, are used as host plants(Wynne et al. 1980). Plants are grown in modi-fied Leonard jars similar to those proposed byWacekand Aim (1978). The jars and a 2:1 sand:vermiculite medium are autoclaved before useto prevent contamination.

Seeds of each genotype are surface-sterilizedby soaking in calcium hypochlorite solution (10gin 150 ml water) for 10 min followed by rinsingwith sterile water five times. The groundnutsare then pregerminated in sterilized vermiculiteand placed 25 mm into the medium in the jars.Before covering the seed, a 1 ml suspension ofthe proper rhizobial strain (approximately 109

cells/ml) is added aseptically to the seed for alltreatments except for an uninoculated controlwhere sterile culture medium alone was added

96

97

Table 2. Origin of Rhlzoblum isolates collected from South American groundnuts.

Coll. No. Isolated from Area collected Soil description Date collected

77 Colorado Chico del Palmai' Cototo, 10 km E of Villa 11 Apr 1977(red seeds) Montes

92 Overo Colorado Blanco(grande)

Saavedra, Sta. Cruz Dark black loam 19 Apr 1977

138 Overo Puento de Mataral, Sta. Cruz 25 Apr 1977146 Overo Valle Abajo, Mairana 28 Apr 1977150 Palido Teneria — Aiquile, dept. Brown sandy loam

Cochabamba29 Apr 1977

151 Sara Mani Mesa Rancho —Aiquile Medium heavy, dark brown 29 Apr 1977

to the seeds. Anitrogen control (10 ml of a 1 mgN/ml solution of N H 4 N O 3 applied three timesduring the test) is also included. The seed andinoculum are then covered with sand. The jarsare watered through the glass tube into thebottom storage area. The distilled water movesthrough a 6 mm thick nylon wick up into themedia in the upper jar. Treatments are repli-cated five times with plots arranged in a ran-domized block design in the greenhouse. Nu-trient solution (150 ml) is added twice during thegrowing period. The nutrient solution consistedof Bond's Stock salt mixture supplemented withzinc, molybdenum and cobalt micronutrients.After 50 days of growth, the plants are har-vested. Plant color is rated on a scale of 1 -3 with1=green and 3=yellow. Nitrogenase activityis measured for the root system of each plantusing acetylene reduction methodology.Nodules are counted and removed so thatnodule mass can be determined. The root andplant tops are dried, weighed, and the tops areground for determination of nitrogen using theKjeldahl technique.

We have evaluated several strains ofRhizobium in the greenhouse for their ability tofix nitrogen. Rhizobial strains have been foundto significantly influence plant color, plant dryweight, nodule number, nodule mass, percentnitrogen, total nitrogen, and nitrogenase acti-vity (Table 3). Strains often perform differentiallyon the two host genotypes giving a significanthost x strain interaction for traits indicative oftheir nitrogen fixing ability. This strain-hostspecificity suggests that rhizobial strains mustbe screened in symbiosis with diverse hosts orwith the host genotype with which they aregoing to be used.

Total nitrogen accumulated is the best mea-sure of the efficiency of a rhizobial strain.However, both plant color and plant dry weightare significantly correlated with total nitrogensuggesting that the measurement of these twotraits is sufficient in evaluating strain efficiencyin greenhouse studies (Table4). Thesetraits canbe utilized by researchers with limited resourcesto screen rhizobia for effectiveness in symbiosiswith local groundnut genotypes.

From the more than 100 unique isolates thatwe have evaluated in the greenhouse, we haveidentified several strains that fix more nitrogenthan the commercial strains used as checks.Although additional testing is needed, thesestrains are now available to other rhizo-biologists interested in cowpea rhizobia.

Field Evaluat ion of Rhizobia

After greenhouse evaluation, we test the nitro-gen fixing ability of rhizobial strains in the fieldin the presence of endemic rhizobia (Elkan et al.1980). In a preliminary study we evaluatedstrains previously tested in the greenhouse fortheir nitrogen fixing ability in thefield in ordertocompare field and greenhousetest results. Ninestrains of Rhizobium in symbiosis with 48genotypes were tested in a field previouslyplanted to groundnuts.

The rhizobial strains applied in a water sus-pension significantly influenced nodulation (0.05level of probability) and nitrogen fixed as mea-sured by nitrogenase activity (0.01 level). Whenaveraged over the 48 host genotypes, thegreatest nodulation was produced by strain176A34 (Table 5). Strains 176A22 and 3G4b4also produced significantly more nodules than

98

99

Table 4. Correlation coeffleiants for nitrogan-flxlng tra its in two graanhouso studies.

Trait

Plant Nodule Nodule Percent NitrogenaseTrait Study weight number mass nitrogen Total N2 activity

Plant color* 1 - . 9 3 * * - . 84 * * - .75* - . 95 * * - . 9 5 * * - .89* *2 - . 9 3 * * - .44 -.54 - . 9 4 * * - . 9 7 * * - .78* *

Plant weight (g) 1 — .79** .54 .83** .99** .83**2 — .45 .61 .90** .97** .73*

Nodule number 1 .89** .83** .82** .75*2 — — .92** .33 .39 .47

Nodule mass (g) 1 .89** .67* .68*2 — — — .49 .54 .68*

% Nitrogen of plant 1 — — — . 8 1 * * .57*2 — — — — .97** .86**

Total N2 of plant (g) 1 — — — — .86**2 — — — — — .78**

a. Rating 1 = green and 3 - yellow.* ** Indicates simple correlation coefficients significant at 0.05 and 0.01 levels of probability.

Tabla 5. Maan nodulation rating and nl-troganaaa activity for strains ofRhiz oblum and an uninoculated con-trol for fiald grown groundnuts.

Nodulation NitrogenaseStrain rating* activityb

3G4b20 2.81 39.1176A34 3.10 38.7176A22 3.07 35.13G4b5 3.06 35.83G4b4 3.07 31.0

3G4b21 2.98 32.842B2 3.06 33.832H1 2.93 35.732Z3 3.04 31.0Control 2.89 32.5

LSD (0.05) 0.17 3.0

a. Rated 156 days after planting with 1 = little and 5 - heavynodulation.

b. C2H4/plant per hr. Mean over 48 genotypessampled91, 95,100, 119 and 127 days after planting.

the inoculated controls which were inoculatedwith the naturally occurring strains. Thegreatest nitrogenase activity, however, occur-

red with strain 3G4b20. Strains 176A34, 3G4b5and 32H1 also had significantly higher nitro-genase activity than the naturally occurringstrains. Conversely, strains 3G4b4 and 3273 hadslightly but insignificantly lower nitrogenaseactivity than the endemic strains.

The nitrogenase activity for the rhizobial st-rains when applied to Florigiant, a Virginiacultivar that is grown on most of the acreage inNorth Carolina, was determined for five sampl-ing dates (Table 6). All plots of Florigiant includ-ing the uninoculated control were heavily nodu-lated. Six of the nine strains, however, hadslightly higher mean nitrogenase activity thanthe naturally occurring strains (control),although only strain 3G4b21 was significantlybetter than the control. These data indicate thatsome strains are able to compete for infectionsites and are more effective than naturallyoccurring strains. Strain 42B2 successfullycompeted for infection sites but produced lesseffective nodules than the naturally occurringstrains. This strain was also ineffective ingreenhouse evaluations.

Nitrogenase activity measured in thegreenhouse forthese same strains in symbiosiswith a Spanish and Virginia cultivar was corre-lated (r = 0.73*) with mean nitrogenase activity

100

Table 6. Nltroganaaa activity C2H4/hrpar plant) for strains of Rhlzoblum and an unlnoculated control forpeanuts of cv Florlgiant for f ive sam-pling datas.

Days after planting

Strain 91 95 100 119 127 Mean

3G4b20 49 70 64 69 28 56176A34 45 50 61 49 20 45176A22 52 60 68 65 30 553G4b5 49 52 74 61 32 543G4b4 58 50 73 48 30 52

3G4b21 55 71 69 74 33 6042B2 44 47 45 49 18 4132H1 38 50 71 66 39 5332Z3 37 56 56 62 26 47Control 48 51 54 64 26 49

Mean 47.4 55.6 63.6 60.6 28.3 51.1

LSD (0.05) Sa mpling date 8 LSD (0.05) Strain 12

in the field. This indicates that screening ofrhizobial strains in the greenhouse is effectiveas a preliminary predictor of rhizobial strainperformance in the field.

A similar field study conducted during 1979involved 10 rhizobial strains and two groundnut

cultivars, Florigiant and Spantex, (Spanishtype). The strains significantly influenced nodu-lation, nitrogenase activity and plant weight butnot yield of fruit (Table 7). A significant (0.05level) genotype x strain interaction was foundfor plant weight, indicating that rhizobial strainswere not equally effective for the twogroundnut cultivars (Table 8). These resultsstrongly suggest that the host genotype mustbe considered in rhizobial strain selection.

These field data are not very dramatic butthey are very encouraging. Considering that soilfertility and endemic rhizobial populations arehigh enough to produce high yields, resultsunder these test conditions can be translatedinto spectacular yield increases on nitrogendeficient soils with ineffective or low rhizobialpopulations.

Identification of CowpeaMiscellany Subgroups

The identification of effective strains of rhizobiathrough plant tests in the field and greenhouseis slow and tedious. It would be advantageous ifit were possible to identify a subgroup of thecowpea rhizobia whose primary host cuitivar is

Table 7. Strain and control means for yleld and nitrogen-fIxlng traits for field-grown groundnuts.

Nodule8Nitrogenase Shoot Yield per

plantNumber Dry wt activity weightYield per

plantStrain treatment (mg) C2H4/plant per hr) (g) (g)

Control(endemic strain) 396abc 475bcd 1.67abc 54.1abc 718a

Nitrogen control 276c 370d 1.17c 59.7abc 646a32H1 427abc 442bcd 1.51abc 62.5ab 726aCB 756 334bc 378cd 1.87a 56.3abc 562a

3G4b5 485abc 503a-d 1.70abc 53.9abc 562a

3G4b21 593a 727a 1.88a 70.2a 695aNC 146.1 642a 625abe 1.44abc 54.0abc 541aNC 92 584a 642ab 1.78ab 53.6abc 634aNC 7.1 553ab 465bcd 1.28bc 51.9bc 654a

NC 3.1 458abc 488a-d 1.65abc 53.1be 597a

NC 71 437abc 322d 1.62abc 44.5c 542aNC 56 396abc 501a-d 1.94a 61.4ab 650a176A22 545ab 538a-d 1.64abc 55.7abc 595a

NC 120 500abc 494a-d 1.67abc 67.6ab 686a

a. Nodule number, welghtand shoot weight are means for plants sampled 59 and 166 days after planting. Nltrogenase activity,59 days after planting, and fruit weight, 166 days after planting, are means for single sampling date.

Means with different letters are significantly different at 5% level according to Duncan's m ultlple range test.

101

Table 8. Ranking of strains of Rhixobium asthay affact plant waight for a Spanish and Virginia groundnut cul-tivar.

Rank Florigiant Spantex

1 32H1 NC 1202 CB 756 3G4b213 NC 146.1 NC 564 NC 3.1 32H15 NC 7.1 176A226 3G4b21 CB7567 3G4b5 NC 146.18 NC 120 3G4b59 NC 92 NC 3.1

10 NC 56 NC 7111 176A22 NC 9212 NC 71 NC 7.1

the groundnut or a specific cultivar-group ofgroundnuts.

We have adapted for use with Rhizobium sptwo DNA-DNA hybridization techniques whichallow us to rapidly determine the genetic rela-tionship of isolates within this group of rhizobia.Isolates from individual legume cultivars nodu-lated with cowpea miscellany rhizobia are beingcompared using these hybridization techniquesto determine if there is (or are) any subgroup/sof cowpea rhizobia favoring groundnuts. Con-versely, if this host-isolate interaction is deter-mined to be truly wide spectrum, we hope todetermine if the more ineffective and effectiveisolates can be genetically grouped. This studyis in the preliminary stages. The genetic diver-sity of this group of bacteria is apparent fromthe DNA-DNA hybridizations. Early evidencepoints to the possibility that bacteria moreefficient in nitrogen fixation with groundnutsare identifiable. If the presence of subgroups (orsubspecies) is confirmed, then it would berelatively easy to identify subgroups of thecowpea miscellany, thus reducing the need forplant tests. This work is continuing and is beingexpanded in our laboratory.

Selection of EfficientHost Plants

A second approach to increasing nitrogen fixedby groundnuts, which is applicable regardless

of whether plants are well nodulated by nativerhizobia or whether inoculation is required foradequate nodulation, is to develop hostgenotypes that are more efficient in fixingnitrogen. Although symbiotic nitrogen fixationhas been studied for almost a century, littleeffort has been given to increasing nitrogenfixation in legumes through breeding. Enhanc-ing the nitrogen fixing process in a leguminouscrop through breeding requires (1) ample gene-tic variability, (2) an understanding of the gene-tic control of the process, (3) a technique formeasuring the desired trait indicative of nitro-gen fixation, and (4) a breeding strategy toefficiently utilize the variation.

Genotypic Variationin Nitrogen Fixing Traits

Differences in nodulation for groundnutgenotypes in the field were first reported byDuggar (1935a). Duggar (1935c) found that a runner (ssp hypogaea) genotype developedlarger and more nodules than a Spanish (sspfastigiata) genotype. Inoculation with a singlestrain of Rhizobium increased nodulation of theSpanish line but not of the runner. Albrecht(1943) observed significant increases in fruityield of a Spanish line when inoculated withthree single strains of Rhizobium and a com-mercial inoculum, while a runner type did notrespond to any of the treatments.

Burton (1976) found differences in nitrogenaccumulation among peanut cultivars grown inthe greenhouse with fixation being the onlynitrogen source. Inoculated with single strainsof Rhizobium isolated from plants of four gen-era, cv Florunner, a Virginia type, was consis-tently higher in nitrogen content than theSpanish cultivars, Comet, Starr and Spantex.

We have found host plant differences innodulation and nitrogen fixing activity in bothgreenhouse and field studies (Wynne et al.1978). Genotypic differences in nodulation bythe native rhizobia found in North Carolinagroundnut fields have also been observed. Thenodulation for 48 genotypes shown in Table 9 istypical of the response observed in NorthCarolina. Virginia types such as cvs Florigiant,Va-72R, NC-5 and NC-6 are more heavilynodulated than Spanish or Valencia types suchas cvs Spanhoma, Spantex, Starr, Argentine,Tennessee Red or New Mexico Valencia.

102

Table 9. Ganotyplc maans for nodulation in North Carolina flald study during 1977 at tha UpparCoastal Plain Research Station. a

Modulation NodulationGenotypes X Genotypes X

1. Starr 1.45 25. PI 221068 4.452. Tamnut 74 2.25 26. PI 241633 2.453. Georgia 255 2.60 27. PI 158850 3.004. G-169 2.45 28. PI 158852 3.255. EM 12 1.65 29. Spanhoma 2.25

6. Florunner 2.75 30. Spantex 2.407. Florigiant 4.90 31. Dixie Spanish 2.858. Va 72R 4.85 32. Starr 2.209. Early Bunch 4.30 33. Argentine 2.10

10. UF 714021 3.90 34. Schwarz 21 2.05

11. NC 6 3.75 35. Chico 2.0512. Tifrun 3.65 36. PI 337396 3.1013. A 69 4.10 37. PI 261954 2.8514. UF 75102 3.00 38. PI 261955 3.0015. Va 70-64 4.50 39. Tennessee Red 2.80

16. NC 5 4.35 40. N. M. Valencia 3.1517. NC 2 3.45 41. PI 275743 2.2018. NC-FIa 14 3.35 42. PI 275744 3.0519. NC 4 3.90 43. PI 275078 2.5020. PI 268837 3.00 44. Greg. #182 1.30

21. PI 313946 3.50 45. Greg. #190 1.1522. PI 313947 3.80 46. 71 SAN 290 2.1023. PI 313950 4.45 47. 71 SAN 291 1.9024. A. monticola 2.80 48. NC 3033 3.25

a. Nodulation rated 156 days after planting with 1 = little and 5 - high.

Nodulation for the genotypes listed in Table 9 was measured at a single harvest date nearmaturity. We have found estimates of nitrogenfixing traits at a single harvest may not bereliable as an indicator of the relative perfor-mance of a genotype. For example, when eightcultivars were sampled four times during thegrowing season for their nitrogen fixing ability,both cultivars and harvest dates significantlyinfluenced nodulation and nitrogenase activity(Table 10). The dateXcultivar interaction wasalso significant for all three traits. The twogenotypes from the ssp fastigiata, TennesseeRed and Spanhoma, had lower mean nodulenumber, nodule weight, and nitrogenase acti-vity when averaged over all harvest dates.Florigiant, the predominant cultivar in NorthCarolina, had the highest mean nodule number,nodule weight, and nitrogenase activity whenaveraged over all sampling dates. However, the

ssp fastigiata cultivars were not lowest at allsampling dates nor was Florigiant highest for allsampling dates. These and other unpublisheddata suggest that selection of a genotype basedon a single evaluation of nitrogen fixing abilityduring the growing season may not alwaysidentify the superior genotype.

The seasonal pattern of nodulation andN2(C2H2) fixed was similar in this and other fieldstudies. The pattern is better illustrated frombimonthly sampling dates for the cultivarsFlorigiant and Argentine (Figs. 1 and 2).Nodulation increased during the growing sea-son until a peak was reached 84 days afterplanting for Argentine and 98 days after plant-ing for Florigiant. Plants of Florigiant averaged1470 nodules compared to 908 for Argentine atthe time of maximum nodulation. Nitrogenfixation increased during the growing seasonuntil a peak was reached 84 days after

103

Table 10. Maana for datas by cultivara for nitroganaaa activity and noduiation (Lawiaton, North

Carolina, 1978).

planting. Nitrogen fixed decreased after this

date. Maximum N2(C2H2) values exceeded

70 umol C2H2/plant per hr for Florigiant compar

ed to less than 50 for Argentine. Unfortunately,

total nitrogen analyses have not been com

pleted and the relationship of noduiation and

N2(C2H2) valuestototal nitrogen are not known.

The rapid increase in nitrogen fixation during

the growing season corresponds to the time of

fruit formation and filling, and the decrease

corresponds to maturation.

These data suggest that a single evaluation of

the nitrogen fixing ability of a genotype using

acetylene reduction if taken during the period of

peak activity might be effective for preliminary

screening of genotypes for nitrogen fixation.

However, selection using total nitrogen ac

cumulated or dry matter accumulated through

104

Figure 1. Means of cultivars for nitrogenase

activity (µ mol C2HAIplant per hr)

over harvest dates (Clayton 1978).

Sampling date (days after emergence)

Cultivar 28 56 84 117

Nitrogenase activity (µ moles C2H4/plant per hr)

Tennessee Red 4.21 15.59 24.66 17.01

Spanhoma 3.35 13.79 21.69 13.44

Florunner 3.86 23.04 37.33 24.69

B1 1.77 6.04 28.87 27.62

Florigiant 5.51 18.83 35.12 34.57

NC 4 1.76 15.59 41.55 26.66

NC 6 3.93 20.13 33.99 34.18

Early Bunch 4.68 17.64 29.56 24.51

Nodulation (nodules/plant)

Tennessee Red 200.6 666.0 923.1 857.6 Spanhoma 162.1 492.4 613.0 494.0 Florunner 213.9 771.9 1380.3 1051.8

B1 151.5 460.9 1315.9 950.1

Florigiant 178.3 771.3 1440.3 1445.1

NC 4 202.9 600.7 1273.9 1659.0

NC 6 187.2 948.5 1265.8 1302.5

Early Bunch 254.0

Nodul

909.5

e weight (g/plant)

1320.4 1266.7

Tennessee Red 0.20 0.75 1.09 1.13

Spanhoma 0.26 0.60 0.90 0.80

Florunner 0.23 1.26 2.37 1.45 B1 0.27 0.57 1.55 1.44

Florigiant 0.21 1.11 2.90 2.77

NC 4 0.41 0.87 2.10 2.50 NC 6 0.46 1.28 2.34 1.78

Early Bunch 0.45 1.21 1.47 1.37

Figure 2. Means of cultivars for nodulation (nodule number/plant) o ver harvest dates (Clayton 1978).

the growing season is almost certain to be moreeffective than N2(C2H2) measured once or evenseveral times during the growing season. How-ever, several N2(C2H2) measurements duringthe growing season might be useful in choosingparents. Two lines producing similar amountsof nitrogen but having different peak periods ofactivity as determined by acetylene reductionmight produce transgressive segregates.

Quantitative Geneticsof Nitrogen Fixation

We have investigated the genetic control ofnitrogen fixation using a diallel cross in thegreenhouse and a population of late generationlines in the field.

Early Generat ion: Greenhouse

The F1 generation of a diallel cross of 10 cul-tivars from South America was evaluated in ananalysis of gene action for traits related tonitrogen fixation. Hybrid progenies were sig-nificantly different for all traits (Table 11). Gen-eral combining ability, which is usually indica-tive of additive gene action, was significant andgreater than specific combining ability for nodu-lation, N2(C2H2) fixed, plant weight, nitrogencontent and total nitrogen. Correlations be-tween parental and general combining abilityeffects were nonsignificant for all traits, sosimple evaluation of lines for nitrogen fixingcapacity in the greenhouse may not identifysuperior parents for use in breeding programs.

Late Generation: Field

Thirty F4 generation lines from a Vir-ginia x Spanish cross were grown at two fieldsites in order to determine the genetics of traitsindicating nitrogen fixation for a population oflate generation lines. The Virginia parent (NC-6),a high yielding Virginia cultivar, is well nodu-lated by the indigenous rhizobial strains inNorth Carolina, while the Spanish parent (922)is poorly nodulated. Plot means for N2(C2H2)fixed, nodule number, nodule weight and dryweight of plant were analyzed considering loca-tions and entries as random effects. Althoughthe study when completed will consist of sev-eral sampling dates over years, parental andline means for one sampling date 90 days afterplanting suggest that sufficient variability existsfor progress from selections in this population(Table 12). The Spanish line is lower in nodula-tion, has less nitrogenase activity and smallerplant weight than the Virginia parent. The rangeof means for the 30 lines generally equal orexceed the range of the parents. Genotypicvariance was estimated from the varianceamong the means for the 30 late generationlines. These estimates were used to estimateheritability as follows:

Where: oG = estimate of genotypic variance,

= estimate of error variance, and

Heritability estimates ranged from 0.45 fornodule numberto0.80forN2(C2H2) fixed (Table13). These estimates indicate that selection fortraits indicative of nitrogen fixation should beeffective for this population. Selections will bemade and the response to selection for nitrogenfixing traits and the effect of selection fornitrogen fixation on productivity will be deter-mined.

An Alternative Breeding Strategy

It has been suggested that the nitrogen fixationin the field may be limited to a large extent bythe availability of photosynthate. Enrichment ofthe atmosphere in the foliar canopy of

105

Table 11. Maan squares from the diallal analysis of characters Indicative of nitrogan-fIxlng ability.

Nodule Nitrogenase Plant Nitrogen Total

Nodule mass activity weight content nitrogen

Source df number (mg) ( µmnol C2H4/plant per hr) (g) (%) (mg/plant)

Blocks 3 4742** 64505** 73.85** 7.85** 0.5965** 5780** Genotypes 98 1477** 10030** 6.47** 1.92** 0.1418** 2190**

Parents 9 726 8543 6.09 0.60 0.1508 534 Hybrids 88 1562** 10132** 6.58** 2.08** 0.1423** 2378** General Combining Ability 9 4216** 26950** 17.10** 3.72** 0.4910** 3327** Specific Combining Ability 35 1533** 263** 4.68 1.97** 0.0699 2252** Maternal 9 1433** 16796** 3.74 2.32** 0.2197** 3674** Reciprocal 35 941 5964 6.50* 1.69 0.1052 1954**

Parents vs hybrids 1 723 14423 0.08 0.27 0.0143 479 Error 280 742 4825 3.97 0.53 0.0845 619

Table 12. Parental means and range of means for single sample 90 days after planting of

groundnut parents and F4 generation population.

Table 13. Herltaboility estimates for nitrogen

fixation traits for late generation

lines from cross of Spanish and Vir

ginia lines sampled 90 days after

planting.

groundnuts with 1500 ppm carbon dioxide dur

ing daylight hours increased nitrogen fixation,

measured by the acetylene reduction assay, by

60% and also increased plant growth and nodu-

lation supposedly because of larger amounts of

available photosynthate (Hardy and Havelka

1976; Havelka and Hardy 1976). Diurnal studies

and shading experiments at ICRISAT (Dart

1977) and leaf removal studies at North Carolina

(unpublished) also suggest that the rate of

nitrogen fixation is governed by the availability

of photosynthate. Once the groundnut plant

enters the reproductive stage the nodules, as a

photosynthate sink, must compete not only

with the growing vegetative parts, but also with

the developing fruit. Hardy et al. (1971) reported

that over 90% of the total amount of nitrogen

fixed occurred during the period of fruit forma

tion and maturation with rate of fixation enter

ing an exponential phase at or about the time of

pegging. Since variation in photosynthetic rates

and net photosynthate accumulation has been

demonstrated for groundnuts (McCloud et al.

1977; Pallas and Samish 1974; Pallas 1973;

Williams et al. 1975; Emery et al. 1973), it should

be possible to select photosynthetically

superior genotypes which fix more nitrogen.

Preliminary analysis of several field studies

conducted in North Carolina indicates that there

is adequate variability in net photosynthetic

efficiency (biological yield) to select genotypes

that are more efficient in accumulation of

photosynthate (Ball et al. 1979). Furthermore,

106

Means over locations

Identity Nodule

number

Nodule

weight

(g)

Nitrogenase activity

( µmol C2H

4/plant per hr)

Plant

dry weight

<g>

Spanish parent (922)

Virginia parent (NC 6)

F4 lines

255

474

152-391

0.245

0.518

0.156-0.453

1.783

4.028

1.112-4.103

20.3

29.9

12.7-29.5

Trait Estimate

Nodule number

Nodule mass (dry wt/plant in g)

N2 (C2H2) in µmol C2H

4/plant per

Dry weight/shoot (g)

hr

0.45

0.63

0.80

0.74

we have found biological yield (total dry mat-ter), economic yield (fruit) and nitrogen fixedN2(C2H2> to be positively correlated (r = .48**-.72** with 38 df). This suggests thatgroundnut breeders can indirectly select forgreater nitrogen fixation by selecting for biolo-gical and/or economic yield. Thus selection foreconomic yield may be an effective method ofincreasing nitrogen fixation when groundnutsare well nodulated by native rhizobia. Thishypothesis is presently being tested in studiesat North Carolina.

S u m m a r y

The atmospheric nitrogen fixed by groundnutscan be increased dramatically by the selectionand use of effective strains of Rhizobium if thegroundnut plants are poorly nodulated or nodu-lated with ineffective strains. Because of a significant genotype x strain interaction, thehost genotype must be considered in strainselection. Strains can be selected after theyhave shown broad adaptation in symbiosis witha number of diverse host genotypes or theymay be selected in symbiosis with the singlehost genotype to be grown.

Sufficient variability exists for selection ofhost genotypes with greater nodulation andgreater nitrogen fixing potential. Preliminaryestimates of heritability for late generation linesfrom a Virginia x Spanish cross suggest thatselection should be effective for traits indicativeof nitrogen fixation. However, since biologicalyield and economic yield appear to be corre-lated with nitrogen fixation, it may be possibleto select for higher nitrogen fixation by select-ing for biological yield and/or economic yield.

References

ALBRECHT, H. R. 1943. Factors influencing the effect ofinoculation of peanuts grown on new peanut lands.Proceedings of the Soil Science Society of America8: 217-220.

ALLEN, 0. N„ and ALLEN, E. K.. 1940. Response of thepeanut plant to inoculation with rhizobia with spe-cial reference to morphological development of thenodules. Botanical Gazette 102: 121-142.

BALL, S. T., WYNNE, J. C, and ISLEIB, T. G. 1979. Net

photosynthetic efficiency and partitioning of photo-synthate in peanut cultivars (Abs.). Proceedings ofthe American Peanut Research and Education As-sociation 11: 43.

BERENYI, N. 1962. Some influences of nitrogen fertili-zation and seed inoculation with rhizobia on thegrowth and nitrogen fixation of peanuts. M. S.thesis, Dept. of Soil Science, North Carolina Univer-sity, Raleigh, USA.

BURRILL, T. J., and HANSEN, R. 1917. Is symbiosis possi-ble between legume bacteria and nonlegumeplants? Illinois Agricultural Experiment Station Bul-letin 202.

BURTON, J. C. 1976. Pragmatic aspects of theRhizobium leguminous plant association. Pages429-446 in W. E. Newton and Nyman, C. J., (ed.),Proc. of the 1st International Symposium on Nitro-gen Fixation. Volume 2. Washington State Univer-sity Press, Pullman.

CARROLL, W.. R. 1934. A study of Rhizobium species inrelation to nodule formation on the roots of Floridalegumes. I. Soil Science 37: 117-134.

CHOMCHALOW, S. 1971. The effectiveness of intro-duced Rhizobium strains on 'Rayong' peanut. Thai-land Journal of Agricultural Science 4: 85-94.

COLLINS, W. O. 1943. Preliminary report on legumeinoculation studies. Soil Science Society of Ameri-can Proceedings 8: 221-222.

DADARWAL, K. R., SINGH, C S., and SUBBA RAO, N. S.1974. Nodulation and serological studies of rhizobiafrom six species of Arachis. Plant Soil 40: 535-544.

DART, PETER. 1977. Advisory group meeting on thepotential use of isotopes in the study of biologicaldinitrogen fixation. The ICRISAT MicrobiologyProgram, Hyderabad, India. November 21-25.

DENARIE, J. 1968. Inoculation des legumineuses a Madagascar. Ann. Agron. 19: 473-496.

DOKU, E. V. 1969. Host specificity among five speciesin the cowpea crossinoculation group. Plant Soil30: 126-128.

DUGGAR, J. F. 1935a. The nodulation and other adapta-tions of certain summer legumes. Journal of theAmerican Society of Agronomy 27: 32-37.

DUGGAR, J. F. 1935b. The effect of inoculation andfertilization on the Spanish peanuts and root nodulenumbers. Journal of the American Society of Ag-ronomy 27: 128-133.

107

DUGGAR, J. F. 1935c. Modulation of peanut plants asaffected by variety, shelling of seed and disinfectionof seed. Journal of the American Society of Ag-ronomy 27: 286-288.

ELKAN, G. H., WYNNE, J. C, SCHNEEWEIS, T. J., andISLEIB, T. G. 1980. Field inoculation of peanuts withsingle strain isolates of Rhizobium. Peanut Science(in review).

EMERY, D. A., WYNNE, J. C, and RICE, P. W. 1973. Canreproductive efficiency in cultivated peanuts be im-proved? Oleagineux 28: 399-403.

ERDMAN, L. W. 1943. New developments in legumeinoculation. Soil Science Society of America Pro-ceedings 8: 213-216.

GAUR, Y. D., SEN, A. N„ SUBBA RAO, N. S. 1974a. Prob-lem regarding groundnut (Arachis hypogaea L.) in-oculation in tropics with special reference to India.Indian Academy of Science Proceedings40(5): 562-570.

GAUR, Y. D., SEN, A. N., and SUBBA RAO, N. S. 1974b.Promiscuity in groundnut Rhizobium association.Zbl. Bakt. Abt. II: 129-369.

HARDY, R. W. F., and HAVELKA, U. D. 1976. Photosyn-thate as a major factor limiting nitrogen fixation byfield-grown legumes with emphasis on soybean,Pages 421-439 in P. S. Nutman (ed.), Symbiotic Nit-rogen Fixation in Plants IBP7. Cambridge UniversityPress, Cambridge, Maryland, USA.

HARDY,R.W.F., BURNS, R.C.,HEBERT,R.R.,HOLSTEN,R.D., and JACKSON, E. K. 1971. Biological nitrogen fixa-tion: Pages 561-590 in A key to world protein. PlantSoil. Sp. Vol.

HAVELKA, U. D., and HARDY, R. W. F. 1976. N2(C2H2)fixation, growth, and yield response of field-grownpeanut (Arachis hypogaea L.) when grown underambient and 1500 ppm COs in the foliar canopy.Page 72 in Agronomy Abstracts.

HAWAII, UNIVERSITY OF.1978. Catalogue of strains fromthe NifTALAL Rhizobium collection (abbreviated). Paia,Maui, Hawaii.

ISWARAN, V., and SEN, A. 1974. Some studies on thegroundnut Rhizobium symbiosis. Zentralbl. Bak-teriol Parasit Infektionskr Hyg., Zweite NaturwissAbstracts 129(5): 477-480.

KUMARA RAO,J.V.D.,SEN,A.,andSHENDE,S.T. 1974.Inhibition of groundnut Rhizobium in Indian soils.Indian Academy of Science Proceedings40(5): 535-539.

LOPES, E. S., LOVADINI, L A. C, MIYASAKA, S., IGUE, T.,and GIARDINI, A. R. 1974. Selection of strains ofRhizobium species for peanuts (Arachis hypogaea L.) and Galactia striata (Jacq.). Urban. Bragantia33: CV-CX.

MCCLOUD, D. E., DUNCAN, W. G., and MCGRAW, R. L 1977. Physiological aspects of peanut yield im-provement. Page 90 in Agronomy Abstracts.

MOSTAFA, M. A., and MAHMOUD, Z. M. 1951. Bacterialisolates from root nodules of Zygophyllaceae. Na-ture (Lond.) 167: 446-447.

PALLAS, J. E., Jr. 1973. Diurnal changes in transpira-tion and daily photosynthetic rate of several cropplants. Crop Science 13: 82-84.

PALLAS, J. E., Jr. and SAMISH, Y. B. 1974. Photosynthe-tic response to peanut. Crop Science 17: 478-482.

PANT, S. D., and ISWARAN, V. 1970. Survival ofgroundnut Rhizobium in Indian soils. Mysore Jour-nal of Agricultural Science 4: 19-25.

RAJAGOPALAN, N., and SADASIVAN, T. S. 1964. Someaspects of root nodulation in tropical legumes. Cur-rent Science 33: 197-202.

RAJU, M. S. 1936. Studies on the bacterial-plantgroups of cowpea, Cicer and Dhaincha. I. Classifica-tion. Abl. Bakt. Abt. II 94: 249-262.

SCHIFFMANN, J. 1961. Field experiments on inocula-tion of peanuts in northern Negro soils. Israel Jour-nal of Agricultural Science 11: 151-158.

SCHIFFMANN, J., and ALPER Y. 1968a. Effects ofRhizobium-inoculum placement on peanut inocula-tion. Experimental Agriculture 4: 203-208.

SCHIFFMANN, J., and ALPER Y. 1968b. Inoculation ofpeanuts by application of Rhizobium suspensioninto the planting furrows. Experimental Agriculture4: 219-226.

SCHIFFMANN, J., and LOBEL R. 1970. Haemoglobin de-termination and its value as an early indication ofpeanut Rhizobium efficiency. Plant Soil 33: 501-512.

SHIMSHI, D., SCHIFFMANN, J., KOST, Y., BIELORAI, H., andALPER, Y. 1967. Effect of moisture regime on nodula-tion of inoculated peanuts. Agronomy Journal59: 397-400.

USDA, Cell Culture and Nitrogen Fixation Lab. 1979.USD A — Beltsville Rhizobium culture collectioncatalogue. Beltsville, Maryland, USA.

108

VlDHYASEKARAN, P., BALARAMAN, K., DEIVEEGASUN-DAAUM, M., and RANGASWAMI, G. 1973. Relationshipbetween virulence and auxin production byRhizobium isolates from groundnut. Current Sci-ence 42(2): 66-67.

WACEK, T. J., and ALM, D. 1978. Easy-to-make Leonardjar. Crop Science 18: 514-515.

WALKER, R. H. 1928. Physiological studies on the ni-trogen fixing bacteria of the genus Rhizobium. IowaAgricultural Experiment Station Bulletin 113.

WEAVER, R. W. 1974. Effectiveness of rhizobia formingnodules on Texas grown peanuts. Peanut Science1: 23-25.

WILLIAMS, J. H., WILSON, J. H., and BATE, G. C. 1975. Thegrowth and development of four groundnut{Arachis hypogaea L.) cultivars in Rhodesia. Rhode-sian Journal of Agricultural Research 13: 131-144.

WYNNE, J. C, ELKAN, G. H., MEISNER, C. M., SCHNEEWEIS,T. J., and LIGON, J. W. 1980. Greenhouse evaluation ofstrains of Rhizobium for peanuts. Agronomy Journal72: 645-649.

WYNNE, J. C ELKAN, G. H., SCHNEEWEIS,T. J., ISLEIB,T.G.,PRESTON, C. M., and MEISNER, C. A. 1978. Increas-ing nitrogen fixation of the peanut. Proceedings ofthe American Peanut Research and Education As-sociation 10: 22-29.

109

Studies on Nitrogen Fixationby Groundnut at ICRISAT

P. T. C. Nambiar and P. J. Dart*

Symbiotic nitrogen fixation depends on aninteraction between the Rhizobium strain, hostplant genome and environment. We are exa-mining all the three components with the objec-tive of increasing biological nitrogen fixation bygroundnut.

Rhizobium: Isolation, StrainTesting and InoculationResponse

Groundnut is promiscuously nodulated byRhizobium of the cowpea miscellany (Fred et al.1932). When nodulated with effective (nitrogenfixing) rhizobia, groundnut nodules fix most ofthe nitrogen requirements of the plant (Pettitet al. 1975; Schiftman et al. 1968). Substantialincreases in the yield have been obtained fol-lowing inoculation in fields where peanuts hadnot been grown before (Burton 1976; Pettit et al.1975; Schiftman et al. 1968; Sundara Rao 1971).In fields where groundnuts had been grownearlier, inoculation sometimes resulted in in-creased yield, increase in seed quality, higherprotein and oil content (Arora et al. 1970;Chesney 1975). A decrease in yield followinginoculation has also been reported (Subba Rao1976). Allen and Allen (1940) described differ-ences between Rhizobium strains in nodulationand nitrogen fixation in groundnut. Surveys infarmers' fields in the southern states of Indiashowed considerable variation in nodulationwith 52 out of 96 fields surveyed having poornodulation. Nodulation and nitrogen fixing ac-tivity, as measured by acetylene reduction, wasten times less in some farmers' fields than thatobserved in fields at ICRISAT Center at the samestage of growth of the plant. These observationsindicate that it should be possible to increase

* Microbiologist and Principal Microbiologist respec-tively, Groundnut Improvement Program, ICRISAT.

biological nitrogen fixation in these fields byinoculating with effective and competitiveRhizobium strains.

We collected nodules from farmers' fields inKarnataka and Andhra Pradesh states in Indiaand from them have purified 50 authenticatedRhizobium strains. We also maintain a collec-tion of Rhizobium strains for groundnut ob-tained from all other known major collections inthe world such as USDA (Beltsville), NorthCarolina State University (Raleigh), NifTAL(Hawaii), Dept. of Agriculture, Zimbabwe, andthe Australian Inoculants Research and ControlService. As a part of our collaborative projectwith North Carolina State University (NCSU) onbiological nitrogen fixation, we are testing thesuitability for use as inoculants of Rhizobium strains which have been isolated and charac-terized at NCSU from nodules obtained duringArachis germplasm collection trips in SouthAmerica (Wynne et al. these Proceedings).

Our experiments show that in nitrogen-freesand: vermiculite media in pots, Rhizobium strains vary in their ability to nodulate and fixnitrogen with groundnut (Figs. 1, 2). Althoughthe magnitude of the shoot dry weight wasoften related to nodule dry weight (e.g. strain IC6006, Figs. 1, 2), this relationship was notconsistent with the array of the strains. Becauseof the variability in germination in Leonard jars,pot culture assembly was used for strain test-ing. We sterilize by autoclaving or steaming orheating to 150° C the rooting media and applynitrogen-free nutrient solution through a per-manent 6 cm diameter watering tube which iscovered with a metal cap when not in use. Thepot surface is covered with heat-sterilized gravel(3-6mm) to protect from aerial contamination(Fig, 3). Six seeds are sown per pot and thinnedto three plants/pot.

We have observed a relationship betweenshoot growth, and the amount of inoculumapplied up to 107 Rhizobium per seed when

110

Figure 1. Shoot production by groundnut inoculated by different Rhizobium strains. Three plants per 20 cm dia pot were grown in a sand.vermiculite (2:1) medium, inoculated with broth culture at the rate of 10s rhizobialseed, watered with nitrogen-free nutrient solution and harvested 64 days after planting. Controls received no inoculum; NO3-C received 240 ppm N continuously.

groundnut was grown in pots of sterilized sand:vermiculite. Nodulation followed the sametrend (Table 1). This is in marked contrast to thesituation in soybeans where nodulation andplant growth was reduced in both field and pottrials only if the inoculum was less than15 x 103 per seed (Burton 1975). This indicatesthat one has to ensure an adequate Rhizobium inoculum size in pot trials measuring nitrogenfixation. It also demonstrates the need toexamine the interaction between inoculum sizeand nodulation response in field experiments.

Groundnut and soybean differ in the infectionprocess in nodule formation (Dart 1977), andthis may be the cause of the difference inresponse to inoculum size.

Table 2 summarizes the results of eight inocu-lation trials at ICRISAT Center. Although a response was not always obtained, Robut 33-1,a cultivar which is about to be released inAndhra Pradesh, gave substantial increases inpod yield when inoculated with a strain NC 92.Strain NC 92 was obtained from NCSU andisolated from nodules collected in South

111

Figure 2. Nodule formation by different Rhizobium strains. Conditions as in Figure 1.

America. Robut 33-1 was the variety which mostcommonly responded to inoculation and in twoof the inoculation trials this response was bestwith strain NC 92. It may be worth developingan inoculum with NC 92 specifically for use withRobut 33-1 provided the evidence of poor com-petition ability against strain IC 6009 (Table 3) isnot found with other Rhizobium strains.

Since seed treatment with fungicides is a recommended practice, the inoculum forgroundnut needsto beseparated from the seed.We do this by applying a granular inoculumbelow each seed, the granules being made byinoculating 1-2 mm sand particles with peatinoculum using methyl cellulose as the sticker.

Nit rogen Fixat ion by Groundnut

Nitrogenase Activity Assay

We have studied several parameters thatinfluence acetylene reduction by groundnutroot nodules in our efforts to standardize theassay for measu ring nitrog enase activity of fieldgrown plants. There is a marked diurnal varia-tion in the nitrogenase activity of field grownplants (Fig. 4). The increase in activity afterdaybreak suggests a close link with photosyn-thesis. Thus plants which produce more photo-synthate are likely to fix more nitrogen. It will beinteresting to see if photosynthesis declines in

112

Table 1. Influanca of RMxoblum Inoculumlevel on nodulation and nltroganfixation by groundnut.

Level of Rhizobium applied as broth Shoot dry wt* Nodule dry wt*(number/seed) (g/plant) (g/plant)

3.2 x 109 3.38* 0.13a

5.5 x 107 2.38* 0.12a

4.8 x 104 1.08* 0.03*6.1 x 102 0.97* 0.02*Nitrate control 4.34 0

* Data in each column followed by the same letter are notsignificantly different at the 0.05 level.

Note: Kadlrl 71-1 plants inoculated with strain NC-92 weregrown under semlsterile conditions watered withnitrogen-free nutrient solution and harvested 57 daysafter planting.

Table 2. Summary of Inoculation trials conducted at ICRISA T Center.

Year/Season Soil type Cultivars Strain Pod yield response

Rainy season1977

HF, Alfisol TMV-2Kadiri 71-1

5a/70 Nil

Rainy season1977

LF, Alfisol Kadiri 71-1Robut 33-1, TMV-2

5a/70 TMV-2, 25%, Robut 33-1, 32%

Rainy season1977

HF, Vertisol Kadiri 71-1TMV-2

5a/70IC 6006

Nil

Rainy season1978

HF, Alfisol Robut 33-1ArgentineAH-8189

5a/70ICG-60IC6006Mixture

Nil

Rainy season1978

LF, Alfisol MH-2ArgentineRobut 33-1

5a/70ICG-606S Mixture

Robut 33-1, 26% (NS)

Postrainyseason 1979

HF, Alfisol MH-2Robut 33-1AH-8189

NC92IC6009Mixture

Robut 33-1, 28.5% (NC 92)

Rainy season1979

HF, Alfisol Kadiri 71-1Robut 33-1AH-8189

5a /70 IC6006NC 43.3NC7.2NC92

Robut 33-1, 25.7% (NC 92)


HF, Alfisol Robut 33-1 NC92 Nil

HF - High Fertility LF = Low Fertility

113

Figure 3. Cross section of a pot system.

Table 3. Response of groundnut to Rhixobium Inoculation In an Alfisol ( 1 9 7 8 - 79 postrainy

season).

Pod w light (kg/ha)

Cultivars Uninoculated IC-6009 NC 92

Mixture

(IC 6009 + NC 92)

MH-2

Robut 33-1

AH-8189

2222

3500

2833

1888

3333

2861

1944

4500**

2694

2027

2805*

2805

CV (%) 15.51 **Slg nilficant at 1% level *Significant at 5% level

Figure 4, Nitrogenase activity ( µmol C2H4/g

dry weight of nodule per hour) in

groundnut cultivar Kadiri 71-1. after

81 days of planting, ICRISA T Center,

postrainy season 1976.

the same way as nitrogenase activity in the

early afternoon, when leaf vapor pressure

deficits are likely to be greater. A preliminary

acetylene reduction assay of 14 groundnut lines

selected for variability in foliage production,

showed significant interaction in acetylene re

duction between lines and time of measure

ment of nitrogenase activity — day time assay

at 0900-1100 hr and night time assay at 2100-

2300 hr (Table 4).

Temperatures in the assay bottle greater than

25° C decreased nitrogenase activity of nodu

lated roots of groundnut cv Kadiri 71-1 (Table

5). Excess or insufficient moisture also de-

Table 4. Mean squares from Anova for

nltrogenase activity (µ moles C2H4/

plant par hr) of selected germplasm

linea assayed during day and again at

night.

Table 5. Effect of incubation temperature on

acetylene reduction by peanut roots.

creased acetylene reduction activity (Fig. 5). We

have observed that shading causes a rapid

decrease in nitrogenase activity. When 109-day

old Kadiri 71-1 plants were shaded to 60% of

ambient light intensity, nitrogenase activity was

reduced within a day by 30% (Fig. 6). Plants

grown during the dry season, which received

fewer irrigations but were not allowed to wilt,

produced about half the pod yield of plants

irrigated every 7-10 days. There were indica-

114

Source of variation df Mean square

Replication

Time of assay

Germplasm lines

Interaction

Experimental error

3

1

13

13

81

5500**

374254**

16314**

5659**

1321

** Significant at 1% level

Incubation µmoles C2H4/

temperature plant per hr

25°C 46.34

30°C 33.97

35°C 32.52 CV (%) 42

LSD (0.05) 9.8

Figure 5. Effect of soil moisture on nitrogenase activity. Sixty days old Kadiri 71-1 plants were assayed on different days after an irrigation.

tions of differences between varieties in re-sponse to water stress. Nodule developmentand nitrogenase activity were much reduced bythe water stress. Nitrogenase activity recoveredrapidly after an irrigation.

Seasonal and Cultivar Differences

Figure 7 shows the nodulation and nitrogenfixing activity of cv Kadiri 71-1 (A hypogaea subsp hypogaea, a long-season runner cultivar)and of cv Comet (A hypogaea subsp fastigiata, a short duration erect-bunch cultivar) whengrown in the rainy season 1976 and underirrigation in the postrainy season 1977. In 1976,a 57 day dry period beginning 39 days afterplanting had an overriding effect on noduleformation and nitrogenase activity. For the

rainy season planting, nodules formed rapidlyduring the first 25 days, but the drought re-stricted further nodule formation with littledifference between cultivars. For Comet,nodules changed little in size after 25 days butfor Kadiri 71-1, nodules continued to grow sothat by 75days nodule mass per plant was twicethat of Comet.

In the postrainy season, nodule formationwas slower to start but then increased until 80days after planting when three times as manynodules had formed as in the rainy season. Newnodules were still forming on Kadiri 71-1 at 128days. Nodule dry weight per plant reflected thepattern for nodule number.

Nitrogenase activity per plant and the ef-ficiency of the nodules (nitrogenase/g noduletissue) differed significantly between cultivars

115

Figure 6. Effect of shading on nitrogenase activity of groundnut. Plants grown as an irrigated crop were shaded in replicated plots at 109 days after planting. Acetylene reduction assays were carried out on the same day and on a subsequent day. | indicates the start of shading treatment.

and seasons. In rainy season 1976, nitrogenaseactivity was at a maximum by 25 days, but fromabout 40-70 days, Kadiri 71-1 nodules weremore active than those of Comet. It was onlyafter 40 days without appreciable rainfall thatthe nitrogenase activity of Kadiri 71-1 nodulesdecreased. The pattern of nitrogen fixation inthe irrigated season was quite different, increas-ing until about 75 days, then decreasing rapidly,with differences developing between cultivars.Kadiri 71-1 nodules at 128 days were still moreactive than at any stage during the rainy season.Peak activity per plant during the irrigatedpostrainy season was more than twice that ofthe rainy season.

The difference in symbiotic performance ofKadiri 71-1 and Comet under the drought stressof 1976, as well as between seasons, suggeststhat we can select cultivars which are betteradapted to fix nitrogen under stress conditions.

Nodulation and nitrogen fixation of two cul-tivars MH-2, a dwarf mutant, and Kadiri 71-1was followed throughout the postrainy season(Figs. 8, 9). There were marked differences inthe weight of the nodules per plant and ni-trogenase activity per plant of these two cul-tivars. Except for a short period, however,nitrogenase activity per gram of shoot weightwas very similar for the two cultivars (Fig. 10).This may indicate that in dwarf cultivars such as

116

Figure 7. Seasonal variation in nodule number and nodule weight per plant and nitrogenase activity per gram nodule weight and per plant in cv Kadiri 71-1 and Comet grown during rainy season 1976 and postrainy season 1977 at ICRISAT Center. The postrainy season planting was irrigated.

117

Figure 8. Nodulation of Kadiri 71-1 and MH-2 during irrigated postrainy season.

MH-2, nitrogen fixation is limited by photosyn-thate supply, if we assume that net photosyn-thesis and plant top dry weight are correlated.

Effect of Intercropping

During the 1978 rainy season, we observed thatgroundnuts when intercropped with pearl mil-let, nodulated poorly and fixed less nitrogenthan the sole crop (Fig. 11). Three rows ofgroundnut were intercropped with one row ofmillet which, as commonly practiced, received N fertilizer at the rate of 80 kg N/ha, a level givingnear optimum intercrop advantage. During the1979 rainy season (Table 6) we observed a similartrend in groundnut intercropped in a normallyspaced maize stand (two rows of groundnutbetween maize rows). Interestingly, solegroundnut and groundnut intercropped withmaize which received no N fertilizer, had similarnodule number and nitrogenase activity.

Figure 9. Nitrogenase activity of Kadiri 71-1 and MH-2 during irrigated postrainy season.

The decrease in nitrogenase activity in inter-cropped groundnut could be due to: (1) theinhibition of nodulation by the nitrogen fertilizeradded to the cereal crop (we have observed thatfertilizer nitrogen reduces nodulation and ni-trogen fixation), and/or (2) the light available tothe groundnut in the intercrop decreases asmore N fertilizer is added to the cereal.

Observations from an experiment ingroundnut/sorghum intercropping where diffe-rent shading intensities were created by gradeddefoliation of the sorghum support this (Table7).

We plan to study the intercropping systemmore carefully. It may be possible to increasethe nodulation and nitrogen fixation of inter-cropped groundnut by selecting cereal cultivarswhich allow more light to the groundnut. It mayalso be possible to select groundnut cultivarsmore tolerant of reduced light availability. Anideal cereal/legume intercropping situationwould utilize the maximum nitrogen fixationability of the legume while minimizing nitrogenfertilizer addition to the cereal (for other detailsof these intercropping experiments, see Reddyet al. these Proceedings).

118

Figure 10. Nitrogenase activity per gram of

top dry weight for Kadiri 71-1 and

MH-2 during irrigated postrainy

season.

We have not observed any interaction among

five groundnut cultivars for nodulation and

nitrogen fixation in intercrop and sole crop

(Table 7). In soybeans it has been suggested

that urea has a less harmful effect on nodulation

than nitrate (Harper 1975). We plan to study the

effect of different sources of N fertilizer applied

to the cereal crop and their effect on nodulation

and nitrogen fixation of groundnut as the inter

crop.

Residual E f f e c t s

Rainy season groundnut, when compared with

Table 6. Nodulation and nltrogen fixation by groundnut intercropped with maize.

Figure 11. Nitrogenase activity of sole and

intercropped groundnut.

maize, had a large positive residual effect on

growth and yield of millet in the subsequent,

irrigated postrainy season with an increase in

yield of 650 kg/ha, i.e., 45%. All groundnut

and above-ground maize material and the

groundnut main roots were removed from the

field prior to the millet planting. This seems to

be an effect of groundnut on N uptake by the

millet, and would be consistent with the ex

tremely high nitrogen fixation rates associated

Table 7. Nitrogenase activity of sola and Intercropped groundnut.

Nitrogenase activitya

(µmoles CzH4/plant per hr)

Intercrop Intercrop

(low (high Cultivars Sole crop density) density)

Chico-17200 15.2 11.8 6.8

TMV-2 18.1 12.6 8.3 MK-374 25.8 23.6 12.2 MH-2 15.4 7.9 9.1 Gangapuri 15.7 10.6 6.5

CV (%) 42

a. Intercrop treatment effects ere significantly different for all cultivars.

Note: Groundnut end sorghum were planted in a ratio of 2:1 in the Intercrop. Low density Intercrop wes obtained by removing alternate pairs of leaves of sorghum. Plants were hervested 70 days after planting. Sorghum was fertilized with 80 kg N/ha.

119

Nodule µ moles C2H4/

Treatment Number/plant plant per hr

Sole groundnut 171 21.3

Intercropped groundnut Nitrogen added to maize (kg/ha)

0 164.70 20.10 50 159.50 9.36

100 150.0 7.00 150 134.15 3.52 CV (%) 19.71 30.30

LSD (0.05) 18.90 5.75

with groundnut. The effect could be due to the N left in fine roots in the soil or due to exudation ofN into the soil or due to less removal of availablesoil N by groundnut when compared with maize(Table 8).

Genetic Variabilityin Groundnut GermplasmLines for Nodulation

Varietal differences in nodulation amonggroundnut were reported by Duggar as early as1935(Duggar 1935). We found large differencesamong germplasm lines for nodulation (noduledry weight) and nitrogenase activity during the1977-78 postrainy season and the 1978 rainyseason. The data on nodule weight and ni-trogenase activity were analyzed by the Scott-Knott procedure (Gates et al. 1978). Theclusters formed were classified into low,medium, and high nodulating and nitrogenfixing (as measured by acetylene reduction)lines (Tables 9, 10). The comparison over sea-son indicated an interaction between cultivarand season for nodulation and nitrogen fixa-tion.

Similar host plant differences in nodulationand N2 (C2H 2) reduction have been documentedin North Carolina peanut fields containing na-tive rhizobia (Wynne et al. these Proceedings).From the variation present in the germplasmlines, it seems possible to develop genotypeswith greater nitrogen fixing ability by selectingparents that consistently have high nitrogenfixing ability over seasons. Isleib et al. (1978)from a 10 x 10 diallel study indicated significantaddit ive gene action for nodulat ion, nit-rogenase activity and plant weight.

We have also found groundnut cultivarswhich consistently nodulate on the hypocotyl,often with a subtending lateral root, whereasothers form few or no nodules in this region(Fig. 12). For example, during the 1977 rainyseason, cv NC Acc 10 formed 175 nodules perplant on the hypocotyl (23% of the total nodulesformed) whereas cv NC Acc 770 formed only 12nodules (2% of the total) in this region. Somecultivars such as MK-374, nodulate further upthe stem, beyond the crown of the plant. Wehave observed that cultivars belonging to thebotanical variety hypogaea nodulated better inthe hypocotyl region than those from fastigiata

Table 8. Residualmaize onflsol. a

effect of groundnutmillet grain yield in an

andAl-

First cropYield

(kg/ha)

GroundnutMaize unfertilizedMaize 20 kg N/ha

LSD (0.01)

198013251456360

a Groundnut and maize grown In rainy season 1977 atICRISAT Center, followed by irrigated millet, In dry winterseason 1977-78.

Table 9. Symbio t ic characters ingroundnut germplasm entriesdays after planting).

4 8(85

Range

Nodule number 247-628Nodule weight 0.30-0.75 g/plant-'Nitrogenase activity

µ mol C2H4 plant- 'h-1 36-176µ mol C2H4/gdry wt nodule/hr 95-386

and vulgaris. We are presently studying theheritability of this location difference in noduleformation.

Non-Nodulating Groundnut

The host-Rhizobium interaction in legumes iswell documented. The genetic basis for non-nodulation has been described in soybeans, redclover and peas (Williams et al. 1954; Caldwell1966; Nutman 1949; Holl 1975). Recently Gor-betand Burton reported non-nodulating lines ofArachis hypogaea (L) in the progenies of a cross48 7 A - 4 - 1 - 2 X PI 262090.

During the 1978 rainy season we observedthat F2 plants in the rust screening nursery weresegregating for non-nodulation. All the parentsof the crosses were found to nodulate normally.Later during the rainy season in 1979, non-nodulating lines were found in 14 additionalcrosses (Table 11). All these crosses have a rustresistant, Valencia groundnut as one of theparents [PI 259747; NC Acc 17090, EC 76446

120

Postrainy season 1977-78

Rainy sc

Nodu-Botanical

1st sampling 2nd sampling

Nitro-

Rainy sc

Nodu-

eason 1978

Botanical Nodu- Nitro- Nod il-

sampling

Nitro-

Rainy sc

Nodu- Nitro-Cultivar ICG No. type lation genase lation genase lation genase

Ah 3277 1218 Spanish L L L L L LAh 3275 1216 Spanish L L L L L LNo. 421 3158 Valencia L L L L - -Ah 39 1161 Spanish L L M H L LAh 5144 1235 Spanish L L M M M -NC Acc 888 359 Spanish L L L L M LAh 61 1173 Spanish L L L M L MAh 3272 1213 Spanish L L L M L MNo. 3527 1524 Spanish L - L M L -Faizpur-1-5 1102 Spanish L M L L M M

No. 418 1500,2202 Spanish L L L M - -NC Acc 1337 358 Valencia L L M M M LNC Acc 516 279 Valencia L - M M L -NC Acc 945 366 Valencia L L M M M -NC Acc 699 1630 Spanish L L L M L M

148-7-4-3-12-B 1573 Spanish L - L M - -No. 1780 1508 Spanish L L M L - -NC Acc 738 331 Valencia L - M M M -TG 17 2976 Spanish L L L M L LNo. 3270 1489 Spanish L L L L - -NC Acc 51 263 Valencia L M L L L -TG 8 95 Valencia L L M M L LAh 42 1163 Valencia L - M L M -NC Acc 2651 402 Spanish L L L M M -NC Acc 1002 380 Valencia L - M M M -NC Acc 524 283 Valencia L M M M M MGAUG 1 - Spanish L - M M L LNC Acc 2734 420 Valencia L L M M M LNC Acc 495 1623 Spanish M M L M L LSpancross 3472 Spanish M - M M M L

NC Acc 1286 389 Valencia M L M M M LNC Acc 17149 475 Valencia M L M M M MAh 1069 1196 Spanish M M M M L LKadiri 71-1 Virginia

runnerM M M M L L

Ah 6279 2983 Spanish M - M M - -NC Acc 2600 400 Virginia

BunchM L M M L M

POL 2 154 Spanish M M M M L LJH 171 3375 Spanish M M M M L LNC Acc 1303 393 Spanish M L M M M MNC Acc 975 376 Valencia M M M M M M

Sm-5 2956 Spanish M M M M L L

Continued

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Table 10. Nodulation and acetylene reduction of groundnut cultivars.

Table 10. Continued

Postrainy season 1977- -781st sampling 2nd sampling Rainy season 1978

Botanical Nodu- Nitro- Nodu- Nitro- Nodu- Nitro-Cultivar ICG No. type lation genase lation genase lation genase

Argentine 3150 Spanish M M M L L LTifspan 3495 Spanish M M M L L LRobut 33-1 799 Virginia

BunchM M M M M

"

Pollachi 1 127 Spanish M L M M M MNC Acc 17113 1699 Spanish M M M M M MAh 8254 2962 Spanish M M M M M LAh 7436 1547 Spanish M M M M M -

NC Acc 490 274 Valencia M M M M M MX-14-4-B-19-B 1561 Spanish H M M M M -NC Ace 2821 2405 Virginia H M H M M MNC Acc 2654 404 Valencia H M M H M -

Range of nodulation and nitrogenase activity for the clusters formedNitrogen

Nodulation (g nodule/plant) fixation (µ moles C2H4/plant per hr)

Low Medium High Low Medium HighSeason (L (M) ((H) (L) (M) (H)


1 Sampling 0.08-0.11 0.11-0.16 0.188-0.19 16-28 30-44 -2 Sampling 0.3 -0.38 0.38-0.6 0.6 -0.75 36-64 65-132 166Rainyseason 1979 0.11-0.14 0.14-0.17 - 68-92 93-117 -

Table 11. Crosses In which non-nodulatlngprogenies were observed.

Shantung Ku No. 203 x NC Acc 17142NC Acc 2731 x NC Acc 17090NC Acc 2731 x EC 76446 (292)

NC Acc 2768 x NC Acc 17090NC-17 x NCAcc 17090Shantung Ku No. 203 x NC Acc 17090

Shantung Ku No. 203 x EC 76446 (292)Shantung Ku No. 203 x PI 259747NC-17 x EC 76446 (292)NC-F1a-14 x NC Acc 17090

Rs-114 x NC Acc 17090NC-17 x PI 259747NC Acc 2731 x PI 259747Shantung Ku No. 203 x PI 259747

Figure 12. Differential distribution of nodules on groundnut root. Left, cv NC Acc 10 has many nodules on the hypocotyl. Right, cv NC Acc 770 has only few nodules.

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(292]. Interestingly some segregants formedonly a few, very large nodules, much larger thanthe parents or normally nodulating F2 plants.Acetylene reduction assays showed that theirnitrogen fixing activity on a nodule weight basiswas similar to that of normal nodules on theparents. A preliminary genetic analysis basedon segregation for nodulation vs no nodulationshowed that a pair of independent duplicategenes control nodulation and that non-nodulation is governed by recessive genes(Nigam et al. 1980)

Summary

1. Groundnut yield can be increased by in-oculating with Rhizobium.

2. Nodulation and nitrogen fixation increasedwith increase in the number of Rhizobium inoculum cells per seed.

3. Nodulation and nitrogen fixation decreasedwhen groundnut was intercropped with mil-let, maize or sorghum.

4. Photosynthesis is one of the major limitingfactors in nitrogen fixation as evidenced bydiurnal variation in nitrogenase activity, re-duction of nitrogenase activity on shadinggroundnuts, and reduction of nitrogenaseto different degrees when groundnut isgrown in an intercrop with variable leaf areaindex of the companion crop.

5. There is genotypic variation in nodulationand nitrogen fixation.

6. Non-nodulating lines observed in the F2populations of some crosses have been pur-ified and advanced to Fe.

Acknowledgments

Intercropping experiments were carried out incollaboration with Drs. M. S. Reddy, M. R. Rao,C. N. Floyd and R. W. Willey of the CroppingSystem Program and experiments on non-nodulating groundnut were conducted in col-laboration with Drs. S. N. Nigam and R. W.Gibbons of Groundnut Improvement Program.Wethank MrA.P.Ghugal,MrH. N. Ravishankarand Mr. B. Srinivasa Rao for their excellenttechnical assistance.

References

ALLEN, O. N. and ALLEN, E. K. 1940. Response of thepeanut to inoculation with rhizobia with special re-ference to morphological development of thenodules. Botanical Gazette 102: 121-142.

ARORA, S. K., SAINI, J. S., GANDHI, R. C, and SANDU, R.S. 1970. Study of chemical composition and yield ofgroundnut as affected by Rhizobium inoculation.Oleagineux 25: 279-280.

BURTON, J. C. 1975. Problems in obtaining adequateinoculation of soybeans. Pages 170-179 in Worldsoybean research. Ed. L. D. Hill; lllinoisilnterstatePrinters and Publishers.

BURTON, J. C. 1976. Pragmatic aspects of theRhizobium: leguminous plant association. Pages429-446 in Proceedings of the First InternationalSymposium on Nitrogen Fixation, Vol 2. Eds. W. E.Newton, and C. J. Nyman. Pullman: WashingtonState University Press, USA

CALDWELL, B. E. 1966. Inheritance of a strain-specificineffective nodulation in soybeans. Crop Science6: 427-428.

CHESNEY, H. A. D. 1975. Fertilizer studies withgroundnuts on the brown sands of Guyana. Ag-ronomy Journal 67: 7-10.

DART, P. J. 1977. Infection and development ofleguminous nodules. Pages 367-472 in A treatiseon dinitrogen fixation. Section III: Eds. R. W. F.Hardy and W. S. Silver. Wiley-lnterscience.

DUGGAR, J. F. 1935. Nodulation of peanut plants asaffected by variety, shelling of seed and disinfectionof seed. Journal of American Society of Agronomy27: 286-288

FRED, E. B., BALDWIN, I. L, and MCCOY, E., 1932. Rootnodule bacteria and leguminous plants. Universityof Wisconsin Studies 52: 34.

GATES, C. E., and BILBRO, J. D. 1978. Illustration of a cluster analysis method for mean separation. Ag-ronomy Journal 70: 462-465.

GORBET, D. W., and BURTON, J. C. 1979. A non-nodulating peanut. Crop Science 19: 727-728

HARPER, J. E. 1975. Contribution of dinitrogen and soilor fertilizer nitrogen to soybean (Glycine max L.Merr) production. Pages 101-107 in World soybeanresearch. Ed. L. D. Hill, Illinois. Interstate Printersand Publishers.

123

HOLL, F. B. 1975. Host plant control of the inheritanceof dinitrogen fixation in the Pisum-Rhizobium sym-biosis. Euphytica 24: 767-770.

ISLEIB, T. G., W Y N N E , J. C, ELKAN. G. H., and

SCHNEEWEIS, T. J. 1978. Quantitative genetic aspectsof nitrogen fixation in peanut. Page 71 in Proceed-ings of American Peanut Research and EducationAssociation.

NIGAM, S. N., ARUNACHALAM, V . . GIBBONS, R. W., BAN-

DYOPADHYAY,A.,andNAMBiAR, P. T. C. 1980. Geneticsof non-nodulation in groundnut (Arachis hypogaea L) . Oleagineux (in press).

NUTMAN, P. S. 1949. Nuclear and cytoplasmic inheri-tance of resistance to infection by nodule bacteria inred clover. Heredity 3: 263-291.

PETTIT, R. E., WEAVER, R. W. ,TABER, R. A., and STICHLER,

C. R. 1975. Beneficial soil organisms. Pages 26-33 in

Peanut production in Texas. Ed. J. E. Miller. TexasAgricultural Experiment Station, Texas A & M Uni-versity, Texas, U.S.A.

SCHIFTMAN, J. , and ALPER, Y. 1968. Effects of

Rhizobium-inoculum placement on peanut inocula-tion. Experimental Agriculture 4: 203-208.

SUBBARAO, N. S. 1976. Field response of legumes inIndia to inoculation and fertilizer applications. Pages255-268//) symbiotic nitrogen fixation in plants. Ed.P. S. Nutman. Cambridge: Cambridge UniversityPress.

SUNDARA RAO, W. V. B. 1971. Field experiments onnitrogen fixation by nodulated legumes. Plant andSoil. Special Volume: 287-291.

WILLIAMS, L. F., and LYNCH, D. L. 1954. Inheritance of a

non-nodulating character in the soybean. Ag-ronomy Journal 46: 28-29.

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Physiological Basis for IncreasedYield Potential in Peanuts

D. E. McCloud, W. G. Duncan, R. L. McGraw,P. K. Sibale, K. T. Ingram, J. Dreyer

and I. S. Campbell*

This work is part of a concerted effort at theUniversity of Florida and in Malawi to under-stand the physiological basis for yield potentialin peanuts. While some idea of the yield poten-tial can be obtained from a comparison ofrecent varieties with older ones, the yield for-mation process is dynamic, and one needs toconduct a growth analysis, taking frequent har-vests throughout the season, to understandcrop growth. Simulation modeling (Duncan etal. 1978) is necessary to understand thedynamics of yield formation.

Peanut Production Model

Dry-matter production in plants is derived fromsolar radiation through the photosynthetic pro-cess, and temperature governs the speed ofdevelopment (Fig 1.). There are three pheno-phases in our peanut production model(PNUTS): expansion, podding, and filling. Theexpansion phenophase spans from emergenceuntil canopy closure when ground coverreaches 100%. Crop growth during this phaseis exponential, and is entirely vegetative.The podding phenophase begins 2 weeks

* Professor, University of Florida, Gainesville,Florida, USA (USAID contract in Lilongwe,Malawi); Professor, University of Florida, Gaines-ville, Florida, USA; Assistant Professor, Universityof Minnesota, St. Paul, Minnesota, USA; SeniorResearch Officer, Ministry of Agriculture andNatural Resources, Lilongwe, Malawi; Post-doctoral Research Assistant, University of Florida,Gainesville, Florida, USA; Chief Physiologist, De-partment of Agriculture and Technical Services,Potchefstroom, South Africa and formerlyGraduate Research Assistant, University of Florida,Gainesville, Florida, USA; International Intern,ICRISAT, Hyderabad, India, respectively.

after the first flowers appear and in most of theimproved cultivars this coincides with the stagewhen full ground cover is reached. Pods areadded linearly until a full pod load has been set(Fig 2). The filling phase begins when a full podload has been set, and continues until maturity.

To aid in understanding growth dynamics, wehave developed a computer simulation modelfor use with a small, hand-held minicomputer(Ingram et al. 1980). Two climatological inputs— total daily solar radiation and mean dailytemperature — are used to simulate dry-matterproduction. Other factors such as moisture, soilfertility and disease control are assumedadequate for optimum yields. Five equationsare used in our peanut production model.

Temperature regulates the rate of crop de-velopment according to the developmentalunits required for each particular phenophase.Development units are accumulated by theformula:

(1)where TEMP is mean daily temperature in °C.

Daily assimilate is calculated as:DAS = RAD.PNE.GC (2)

where RAD is expressed in MJ.m-2.day -1

photosynthetic efficiency (PNE) = 1.0, with nofactors limiting photosynthesis. GC is theground cover coefficient. The ground covercoefficient is calculated by:

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where is the sum of the developmentalunits from emergence, EXP is the expansionexponent, and DUE is thetotal developmentalunits for the expansion phenophase. Whenpodding begins, pod dry matter is calculatedby:

PDM = DAS.PLPCF.PART (4)where PL is the pod load coefficient, PCF is the

(3)

Figure 1. Diagrammatical representation of the peanut production model.

pod composition adjustment factor (0.606) whichaccounts for the greater photosynthate neededto produce pods high in oil and protein contentcompared to the vegetative component. PARTis the ratio of daily assimilate flow to podscompared to the total assimilate.

Vegetative dry matter is calculated by:VDM = DAS - (PDM/PCF) (5)

When a full pod load has been set, filling beginsand it continues until maturity is reached. Poddry matter is calculated by equation (4) usingthe pod load coefficient of 1.0.

Our objective for the peanut productionmodel is to simulate potential vegetative andpod dry matter production where the soil ferti-lity, moisture, and plant pests are optimum formaximum productivity.

Climatological andPhysiological Inputs

Two climatological inputs — daily total solarradiation and mean daily temperature are usedin our peanut production model for calculating

potential productivity. If desired, a soil moistureloop can be added as we have done for the IBMcomputer. However, we find potential produc-tivity a useful measure of the uncontrollableclimatic factors.

Physiological parameters which are inputinto the model are: the expansion exponent,developmental units for the expansion, pod-ding and filling phenophases, and the partition-ing and pod weight factors. Initially in eachenvironment for each cultivar a growth analysisstudy with percent ground cover estimates,counts of pod numbers, and measurements ofvegetative and pod dry weights at weekly inter-vals will be necessary. From these measure-ments, the developmental units for eachphenophase can be determined using equation(1).

During the expansion phase, the expansionexponent should be selected by trial and errorgiving the best fit for the increase in vegetativedry weight — equation (3). We used an expo-nent of 2.5 for the Florida data. During thepodding phase, pod load increases in a linearrelation to I DU until a full pod load has beenset.

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Hypothetical

Actual data

Figure 2. Hypothetical vs actual pod loading in Sellie peanuts grown in Florida in 1979.

Partitioning is determined from growthanalysis measurements from the formula:

where PGR is the pod growth rate fitted to thelinear portion of the pod dry weight curve, PCFis the pod composition adjustment factor andCGR is the crop growth rate from the linearportion of the vegetative dry weight curvebefore podding begins. Partitioning is the divi-sion of daily assimilates between reproductiveand vegetative plant parts. Partitioning shouldnot be confused with harvest index which is a static end-of-season computation, inadequateto explain the dynamic growth process; withthe canopy senescence of legumes, harvestindex is inaccurate and useless for evaluation ofbreeding materials.

The pod weight factor can be determinedfrom representative samples of mature pods.

The physiological factors are then used asinitial inputs in the PNUTS model. For weeklygrowth analysis, weekly averages are com-puted for temperature and solar radiation, andthese are then entered in the hand-heldminicomputer. Calculations of the weekly datafor each of the 19 harvests in our study takeabout 20 minutes. If a printer is used, much lesstime is required.

Growth Analysis — SimulationModeling in Florida

In a growth analysis simulation modelingstudy, Duncan et al. (1978) reported the resultswhich are summarized in Table 1.

We found that total dry-matter productionamong the four cultivars did not change; thefour dry matter curves could be superimposed.The crop growth rates did not differ significantlyamong cultivars and 191 kg/ha per day wascomputed as the pooled cultivar mean rate.

Partitioning was the major factor whichchanged among the cultivars and it brought a step-wise yield improvement. Dixie Runner, a 30-year old cultivar produced 2.47 t/ha; EarlyRunner, 20 years old, produced 3.84 t/ha;Florunner, 10 years old, produced 4.64 t/ha; andEarly Bunch, the newest cultivar from theFlorida peanut breeding program, produced5.39 t/ha. Partitioning in the Florida-bred cul-tivars has been increased from 40% thirty yearsago to 98% in the newest cultivar. However, nofurther increases are possible through in-creased partitioning since the upper limit hasbeen reached in the Early Bunch cultivar.

Growth Analysis — SimulationModeling in Malawi

This year in Malawi we have just completed a similar growth analysis experiment to deter-mine the partitioning coefficients for threewidely grown Malawi cultivars compared toFlorunner. This should aid plant breeders ingauging how much improvement is possible inthe Malawi cultivars.

Mani Pintar is a very old, high-yielding intro-duction into the United States from Bolivia. Thevariety was later sent to Malawi. For ManiPintar, the VDW regression produced a crop

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Crop growth rate Pod growth rate Partitioning YieldCultivar (kg/ha per day) (kg/ha per day) (%) (kg/ha)

Dixie Runner 189 + 22 40.5 + 1.6 40.5 2472Early Runner 185 ± 20 74.1 + 6.0 75.7 3843Florunner 212 ± 15 95.0 ± 4.2 84.7 4642Early Bunch 191 ± 20 98.7 + 6.0 97.8 5378

growth rate of 13.4 g/m2 per day (Fig. 3) ThePDW regression was 6.6 g/m2 per day and a partitioning coefficient of 0.81 was obtained.The dashed line represents the adjusted assimi-late flow to pods. Mani Pintar produces highyields largely because of high partitioning ofassimilates to pods. It is not surprising thatMani Pintar has been in the parentage of severalhigh-yielding cultivars such as Makula Red,Apollo, and RG-1.

Chalimbana (Fig. 4) had a crop growth rate of14.4 and a pod growth rate of 5.0 g/m2 per day,which produced a partitioning coefficient of0.57. Plant breeders should be able to achieveconsiderable yield improvement in this cultivar.

RG-1 (Fig. 5) had a crop growth rate of 12.3and a pod growth rate of 6.3 g/m2 per day,which produced a partitioning coefficient of

0.84, similar to Mani Pintar which was used inbreeding the RG-1 cultivar.

Florunner (Fig. 6) was used as a comparisoncultivar to determine if the partitioningcoefficient differed between the environmentsin Florida and Malawi. Florunner had a cropgrowth rate of 12.3 and a pod growth rateof 5.7 g/m2 per day which produced a partition-ing coefficient of 0.76, somewhat lower than0.85 produced in Florida.

However, both the crop growth rates and thepod growth rates were lower in the Malawiexperiment than in Florida. In Malawi the cropgrowth rate was 69% and the pod growth was60% of that in Florida. In Malawi, some factorrestricted photosynthesis; quite likely the factorwas a deficiency of magnesium. This restrictionnecessitated using a PNE factor less than 1.0 in

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Figure 3. Vegetative dry weight, pod dry weight, and partitioning of assimi-lates for Mani Pintar grown in Malawi in 1979-80.

Figure 4. Vegetative dry weight, pod dry weight, and partitioning of assimi-lates for Chalimbana grown in Malawi in 1979-80.

Table 1. Crap growth rates, pod growth ratae, and partitioni ng for four paanut cultlvars grown atGainesville, Florida In 1976.

Figure 5. Vegetative dry weight, pod dry weight, and partitioning of assimi-lates for RG-1 grown in Malawi in 1979-80.

partially alleviated the magnesium deficiency,and in our model the photosynthetic rate (PNE)after pegging had to be increased to85% of thatfor Florida (1.0) in order to produce vegetativeand pod dry weights which would match theMalawi growth analysis data.

We believe this is an example of the value ofsimulation modeling. We want to know if thelow magnesium affected the photosyntheticrates and if the low crop and pod growth ratesaffected partitioning. We will be testing this inan experiment during the 1980-81 growingseason.

A comparison of the actual growth analysis ofMani Pintar data with the data from the PNUTSmodel (Fig. 7) showed very high correlationbetween vegetative dry weights for the linearportion of the curve until podding began — 0.998. For the linear portion of the pod dryweight curve the correlation was 0.992. Thus,the model is excellent for predictingdry weightsover these periods.

Figure 6. Vegetative dry weight, pod dry weight, and partitioning of assimi-lates for Florunner grown in Malawi in 1979-80.

Figure 7. Actual data vs the simulation model for Mani Pintar grown in Malawi during 1979-80.

the model. Soil tests showed very low mag-nesium and calcium levels and a low pH, andsince no dolomitic limestone was available inMalawi, calcic limestone was applied at plant-ing and did not alleviate the magnesium de-ficiency. The appi cation of gypsum at pegging

The discrepancies between actual vegetativedry weight and the model's prediction afterpodding begins are due to the loss of leavesfrom disease and senescence. We believe thatthe difference between the model and the actualdata is a reasonabie estimate of leaf loss.

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Temperature vs Pod Number

Another experiment which we conducted inFlorida is summarized in Table 2 (Dreyer et al.1980). This experiment was conducted to testour hypothesis that the number of pods esta-blished per plant should be inversely propor-tional to the growth rates of the individual podsPeanuts were chosen as the test plant becausewe could vary the pod growth rates in the fieldby cooling or warming the small soil volumeoccupied by the growing pods.

As predicted by the hypothesis, slowergrowth rates per pod, obtained by cooling thepod-zone soil, increased the total number ofpods established per plant. Warming the pod-zone did not increase the pod growth rates andcaused no reduction in the number of pods.When harvest was delayed until maturity foreach treatment, average single pod weightswere the same for each soil temperature. Thus,slower pod growth rates produced largeryields,but a longer filling period was required.

We feel that the particular method used toslow pod growth rate is incidental. The sameresults could have been attained by breedingfor slower growing pods or by chemical treat-ments to achieve the same end, as long as themethod used did not reduce mature podweight. Presumably, an increase in the finalpod weight without affecting the individual podgrowth rate would have affected a similar en-hancement of yield although maturity wouldalso have been delayed. The mean pod growthrate was 8.4 g/m2 per day across all temperaturetreatments. The higher yield for the lowest soiltemperature treatment resulted from the longerpod filling period required.

Physiological Specificationsfor High Yields

Our work on the physiological basis for yieldimprovement in peanuts clearly shows thereare four aspects that promote high yields:(1) a rapid expansion phenophase, (2) a shortpodding phenophase, (3) a long fill ingphenophase, and (4) a high partitioning of as-similates to pods. Our work shows that thesefour are the physiological aspects which, underoptimum growing conditions, are most importantin promoting high peanut yields. Under SAT con-ditions with restricted moisture and fertility,physiological specifications such as droughtand low fertility tolerance must be considered.In addition to these physiological specifica-tions, there are of course the usual diseaseresistance, quality, and other factors for thebreeder to consider.

A rapid expansion phenophase, thetime fromplanting to full ground cover, promotes betterweed control. When the length of the growingseason is fixed by temperature or moisture, a rapid expansion phase saves time which can beused to lengthen the pod filling period therebyproducing higher yields. Flowering and pod-ding should begin before full ground cover isreached. This early flowering and podding alsosaves time and helps shorten the poddingperiod.

A short podding phenophase is a desirablephysiological attribute. Pods should be addedrapidly until a full pod load is set. However, if allpods were set in a single day, and if that daywere cloudy or in a drought-stress period, lessphotosynthate would be available for the podsand the plant would respond by setting fewer

Table 2. Fruiting tone soil temperature, pod number, and pod growth rate for Sellle peanuts grownin Florida, USA, 1979.

Soil temp. Pods harvested Single pod growth rate Mean pod growth rate

CO (no./m2) (mg/pod per day) (g/m2 per day)

23 1060 7.9 8.427 845 9.9 8.430 840 10.0 8.434 830 10.1 8.437 790 10.6 8.4

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pods and the final yield would be lower.Peanuts then would be more like corn which hasa very short critical period at silking when grainnumbers are irreversibly determined. Forpeanuts, the final few days of podding arecritical; however, peanuts, unlike corn, can re-sume podding when conditions become morefavorable. Even under optimum conditions,peanuts have an excess of flowers and pegs, butthis does not mean an "extra" yield potential.Pod load is adjusted to the photosynthate flowto the pods during the last few days of podloading, and under optimum conditions thisload is set by solar radiation and partitioning.

A long filling phenophase is anotherphysiological attribute which contributes tohigh yield in peanuts. We feel that a longerfilling period can be achieved in two ways: by a lower individual pod filling rate, or by a largerseed size with the same pod filling rate. Thecombination of a lower individual pod fillingrate and a larger seed size would promote evenhigher yields, but the penalty would be a muchdelayed maturity.

A high partitioning of assimilates to podspromotes high yields in peanuts. The stepwiseyield improvement in the Florida breedingprogram was largely achieved by increasedpartitioning. The latest cultivar Early Bunchpartitions all of its assimilates to pods, andduring late pod filling, the vegetative canopyshows stress effects of this assimilate drain.

Selection Criteriafor the Plant Breeder

How can the plant breeder utilize this physiolo-gical inforamtion? Some examples of selectioncriteria for the plant breed er for rapid expansionwould be: lack of dormancy, rapid germina-tion, seedling vigor, and rapid spread.

A short podding phase is more difficult toselect for, especially using individual wide-spaced plants. In solid stands the date at thebeginning of flowering when the first 10% of theplants are blooming, and before flowering ter-minates the date at which the last 10% of theplants remain in flower, should be recorded. Thedifference between these two dates in days canbe used as a podding index. The lower this index,the shorter the podding period.

Perhaps the best index for length of fillingperiod is the days from the final 10% cut-off of

flowering to maturity. The longer this period,the longer the filling period. Later maturityalone is not specific enough. What the breederneeds is an index of the actual days spent infilling. In the United States, hybrid corn breed-ers were at this stage 30 years ago. I recentlyasked an eminent U.S. corn breeder howbreeders had achieved higher yields during thelast 30 years. He replied that they have moreeffectively utilized the available growing seasonby selecting for earlier silking without changingthe days to maturity, which is set by frosts in thespring and fall. In physiological terms, thismeans lengthening the filling period. Forpeanuts, the breeding objective from a physiological standpoint should be to select thenew cultivar for the expected length of theparticular growing season to which it will beadapted (which is generally set either by mois-ture or temperature) and to use the largestpossible proportion of the available growingseason for pod filling. This is fine-tuning of a cultivar. It is difficult to select for high partition-ing. Selections for yield can be made, but yieldselection often may not be specific for partition-ing. Perhaps the best approach for the breederis to select the parents in crossing programs forhigh partitioning. In many SAT countries, rapidyield improvement can be made by selecting forhigher partitioning; however, selection for veryhigh partitioning can lead to reduced yieldsunder conditions of environmental stress.

Plant breeders can make rapid progress byselecting for improved partitioning with cul-tivars which have a low partitioning coefficientalthough caution should be exercised for ad-verse conditions. Selecting for rapid expansion,short podding, or long filling periods will bemuch more difficult, time consuming, and willtake considerable innovative ingenuity. There islittle evidence in peanuts or other crop plantsthat the basic photosynthetic process can beimproved; selecting for phtosynthetic ef-ficiency is unlikely to be successful.

References

DUNCAN, W. G., MCCLOUD, D. E., MCGRAW, R. L, andBOOTE, K. J. 1978. Physiological aspects of peanutyield improvement. Crop Science 18: 1015-1020.

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DREYER, J., DUNCAN, W. G., and MCCLOUD, D. E. 1980.Fruit temperature, growth rates, and yield ofpeanuts. Submitted for publication to Crop Science.

INGRAM, K. T., MCCLOUD, D. E., CAMPBELL, I. S., DUNCAN,

W. G., MCGRAW, Ft. L, and SIBALE. P. K. 1980. Aneducational model to simulate peanut crop growthand development in a hand-held mini computer.Submitted for publication to Journal of AgronomicEducation.

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Groundnut in Intercropping Systems

M. S. Reddy, C. N. Floyd and R. W. Willey*

In the developing world, groundnuts are com-monly grown in intercropping systems, espe-cially by small farmers who use traditionalcombinations often involving up to 5-6 crops.Detailed statistics of farming practice aredifficult to obtain, but it has been estimated that95% of the groundnuts in Nigeria and 56% inUganda are grown as mixtures with other crops(Okigbo and Greenland 1976). In the NorthernGuinea Savanna Zone of Nigeria, Kassam(1976) reported that only about 16% of the totalarea under groundnut was in sole croppingwhile about 70% was in 2-4 crop mixtures. Un-derplanting tree crops such as coconut, oilpalm,and rubber trees with groundnuts in the earlyyears of the plantation is also a common featurein S.E. Asia (Hardwood and Price 1976) andIndia (Aiyer 1949).

This paper considers the intercropping ofgroundnut only with other annual crops; itdeals mainly with the cereal intercrops (millet,maize, and sorghum), which are by far the mostimportant intercrops grown with groundnut. Italso considers briefly a further important group— the long-season annuals such as pigeonpea,cotton, castor, and cassava.

Intercropping of Groundnutwith Cereals

Groundnut/Pearl Millet IntercroppingThe groundnut/millet combination has beenchosen for special emphasis at ICRISAT be-cause it involves two ICRISAT mandate cropsand the combination is an especially importantone on the lighter soils of the semi-arid tropics,notably in West Africa and India.

A series of crop physiological experimentshas been carried out since 1978 in four different

* Agronomist, Research Intern, and PrincipalAgronomist, respectively. Cropping Systems,ICRISAT.

seasons at ICRISAT Center, to study the growthpatterns and the resource use in this combina-tion to determine how yield advantages areachieved. The first experiment, conducted dur-ing the rainy season of 1978, compared solecrops with a single intercrop treatment of 1 rowmillet: 3 rows groundnut. Results have beenpresented in detail elsewhere (Reddy and Willey1980a) so they are only briefly summarizedhere.

Growth patterns are plotted in Figure 1. Solemillet showed a very rapid rate of growth,achieving 8134 kg/ha of dry matter in 85 days(Fig. 1b). Sole groundnut growth rate wassomewhat slower, and this crop achieved 4938kg/ha of dry matter in 105 days (Fig. 1a). Drymatter yield of each crop in intercropping isgiven in comparison with an expected yield, thisbeing the yield that would be achieved if thecrop experienced the same degree of competi-t ion in intercropping as in sole cropping.Groundnut growth very closely followed theexpected dry matter yield of 75% of its sole cropyield, whilst millet produced approximatelytwice its expected dry matter yield of 25% of itssole crop yield. In effect, this means thatgroundnut produced about the same yield perplant in intercropping as in sole cropping, whilethe much more dominant millet approximatelydoubled its yield per plant in intercropping.

The combined dry matter yield in intercrop-ping is given in comparison with the yield ex-pected, if there was no yield advantage (or dis-advantage) of intercropping, i.e.,of the LER = 1 (LER = Land Equivalent Ratio, or the relativeland area required as sole crops to produce theyields achieved in intercropping). Figure 1cshows that with time there was an increasingdry matter yield advantage for intercropping; atfinal harvest the actual LER was 1.29, i.e., anadvantage of 29% for intercropping. Grain andpod yields closely followed this pattern and ac-tual LERs were 0.71 for groundnut and 0.55 formillet, giving a total LER of 1.26, or an overallyield advantage of 26% for intercropping.

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Figure 1. Sole crop yields and actual and expected intercrop yields of groundnut and millet.

Resource use was of particular interest in thiscombination. Considering moisture use first,the amounts of water transpired through thesole crops and the intercrop are presented inTable 1. (The amount for the intercrop could notbe apportioned between the crops.) For thecombined intercrop, an expected moisture usewas also estimated by calculating for eachcomponent the amount of moisture whichwould have been used if dry matter had beenproduced at the same efficiency as the respec-tive sole crops. It can beseenthatthiscaiculatedmoisture use was very similar to the actualmoisture use, thus there was no evidence thatintercropping was able to produce more drymatter per unit of water transpired through thecrop.

Light interception patterns are presented inFigure 2. Sole millet showed a particularly rapiddevelopment of light interception, but the solegroundnut was rather slower. The combinedintercrop was intermediate to the two solecrops in the early stages, but by about 60 days itwas similar to both the sole crops; thereafter itdeclined because of senescence and removal ofthe mi l let and then senescence of thegroundnut. Light use by the individual compo-nents in intercropping could not be distin-guished. But the estimated amount of lightenergy which would have been needed to pro-duce the intercrop yields, assuming the same

level of efficiency as the sole crops, was apprec-iably higher than the measured amount inter-cepted (Table 1). Calculation showed that theintercrop appeared to use light with 28% grea-ter efficiency. This agrees very closely with theLERs given earlier, suggesting that the yield ad-vantages of intercropping were due very largelyto more efficient use of light. In fact, during theperiod of maximum leaf area, the intercropsupported a leaf area that was appro-ximately 30% greater than the sole crops. Thusthe greater efficiency of light use may at leastpartly have been because light was more evenlydistributed over more leaves. It could also havebeen partly due to the combination of a C4 cropin the upper canopy layers and a C3 one in thelower canopy layers.

An important feature of this first experiment,however, was that it was conducted at a rela-tively high level of fertilization (80 kg N/ha and50 kg P20s/ha) and the season turned out to beparticularly wet with rainfall well above aver-age. Thus it was considered that a major reasonwhy the higher intercropping yields appearedto be especially associated with increased ef-ficiency of light use could have been becausenutrients and water were not limiting. A mainobjective of subsequent experiments was tore-examine the relative importance of this lightfactor in situations where the below-ground re-sources were more limiting. Results have been

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Table 1. Efficiency of resource use in pearl millet/ground nut intercropping.

Millet Groundnut

Water useSole cropping

Dry matter (kg/ha) 8134.00 4938.00Water used (transpiration, cm) 15.86 19.63Water-use efficiency (kg/cm) 513.00 252.00

IntercroppingDry matter (kg/ha) 4129.00 3821.00Water used at sole-crop 8.05 15.19efficiencies (cm) 23.24Expected water-use efficiency (kg/ha) 342.00Actual water used (cm) 22.79Actual water-use efficiency 349.00

Light-energy conversionSole cropping

Dry matter (kg/ha) 8134.00 4938.00Total light intercepted (kcals/cm2} 14.26 19.25Efficiency of conversion (mg/kcal) 5.70 2.57

IntercroppingDry matter (kg/ha) 4129.00 3821.00Energy required at sole crop 7.24 14.90conversion rate (kcals/cm2) 22.14Expected conversion efficiency (mg/kcal) 3.59Actual interception (kcals/cm2) 17.25Actual conversion rate (mg/kcal) 4.60

Figure 2. Light interception by sole crops and an intercrop of pearl millet and groundnut.

presented in detail elsewhere (Reddy andWilley (1980b), so again they are only brieflysummarized here.

During the postrainy season of 1978, an ex-periment was conducted to study the effect ofno-stress and stress moisture regimes (Table2).The pattern of intercrop results in no-stress wassimilar to that reported in the previous experi-ment and the reproductive yield advantage was25%. Under stress the reproductive yield ad-vantage was rather higher at 29%. The ef-ficiency with which light energy was convertedinto dry matter was calculated as in the previousexperiment; in no-stress the intercrop was 2 1 %more efficient than expected, while in stress itwas only 7% more efficient. Thus the resultssuggest that when moisture is more limiting,the efficiency of light use may be a less impor-tant factor in determining the yield advantage ofthis particular crop combination.

During the rainy season of 1979, an experi-ment was carried out to study the effect of two

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Table 2. Grain or pod yields and land equivalent ratios in pea rl millet/groundnut Intercroppingunder two different moisture regimes (1978 postralny seaso n).

Millet Groundnutgrain yields

Milletpod yields

Groundnut TotalTreatments (kg/ha) LER (kg/ha) LER LER

NO STRESS(Irrigated every

10 days)Sole crop 2674 - 2441 - -1 : 3 Intercrop 1220 0.46 1928 0.70 1.25

STRESS(Irrigated every20 days)

Sole crop 2114 - 2040 - -1 : 3 Intercrop 937 0.44 1734 0.85 1.29

LSD (0.05) withina moisture regime 109 146 0.09

LSD (0.05) acrossmoisture regimes 133 217 0.08

CV (%) Main plots 3.26 4.95 2.57CV (%) Split plots 3.60 4.03 4.38

different nitrogen levels on the millet (Table 3).The pattern of results was again similar to theprevious experiments in that at a high level ofnitrogen (Nso) the reproductive yield advantagewas 2 1 % but this increased under stress (nil N)to 32%. Dry matter yield advantages were evenhigher (Table 3). The efficiency of light energyconversion of the intercrop compared with thesole crops was calculated as in the earlier exper-iments. At Nso, the intercrop was only 14% moreefficient, which was a rather smaller effect thanin the previous experiments. At nil N, however,the improved light use efficiency of the inter-crop was even higher, being 21%. At first, thiseffect at nil N is rather surprising, as it seems tocontradict the earlier suggestion from the mois-ture regime experiment that when a factor otherthan light is more limiting, the efficiency of lightuse is less important. But the results may simplyindicate some essential differences betweenthe moisture stress and nitrogen stress situa-tions which were created. One notable differ-ence of course was that the moisture stressappiied to both component crops, whereas thenitrogen differences applied only to mil let Cur-rent studies are examining situations where

phosphate levels are also varied so that nutritionalstress also applies to the groundnut.

Groundnut/Maize Intercropping

Groundnut is very commonly intercropped withmaize in Southeast Asia and Africa. Mutsaers(1978) reported that in western Cameroon, thefarmer grows groundnut as the main crop withmaize interplanted at a fairly low density. Exper-iments carried out during three seasons in theYaound'e area, Cameroon, to evaluate ground-nut/maize mixtures, gaveyield advantages overpure stands ranging from 6-16%. Evans (1960)obtained yield advantages ranging from 9-54%from five different experiments conducted attwo different locations in Tanzania during 1957and 1958. In Ghana, Azab (1968) studiedgroundnut/maize intercropping by varying thesowing time of each crop. He observed that themean yield of groundnuts was significantlyhigher when sown 4 weeks earlier thanmaize. The traditional practice of sowing bothcrops at the same time gave an intermediateyield. Koli (1975) reported that the yields ofgroundnuts in mixed cropping treatments were

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Table 3. Grain or pod yields and land equivalent ratios in pea rl millet/groundnut Intercroppingunder two different levels of nitrogen applied to the millet (1979 rainy season).

Pearl millet Groundnutgrain yields Pearl

milletpod yields

Groundnut TotalTreatments (kg/ha) LER (kg/ha) LER LER

Sole groundnut - - 2998 - -Sole pearl millet

(0 kg N/ha) 1968 - - -Sole pearl millet(80 kg N/ha) 2872 - - - -

1:3 Intercrop(0 kg N/ha) 1063 0.54 2345 0.78 1.32

1:3 Intercrop(80 kg N/ha) 1436 0.50 2131 0.71 1.21

LSD (0.05) 233 117 0.12CV(%) 8 4 6.71

one-third to one-half the yields obtained fromsole crops, but yield of maize was not reducedto the same extent. The general observation inall reports on the maize/groundnut combina-tion is that groundnut yield is readily depressedby competition from the maize.

A groundnut/maize experiment was con-ducted on an Alfisol at ICRISAT in the rainy sea-son of 1978 to study whether there was anybeneficial transfer of fixed nitrogen from thelegume to the cereal. Treatments consisted ofmaize at 0, 50, 100, and 150 kg/ha of appliednitrogen, and with and without a groundnut in-tercrop. With no applied nitrogen, maize growthwas very poor and obviously nitrogen deficient,and there was no visual evidence of growthbeing any better if the groundnut intercrop werepresent. This observation was supportedby maize grain yields which were un-affected by the groundnut at any level of nit-rogen. The relative yield advantage of inter-cropping compared with sole cropping was44% at zero nitrogen level but this decreasedwith increase in applied nitrogen and it was zeroat the highest nitrogen level (Rao et al. 1979).Since there was no evidence that these differ-ences in yield advantage could be due to differ-ences in nitrogen transfer, it is possible thatthey occurred because intercropping was moreefficient in using soil nitrogen, an effect that wasmore evident at lower levels of applied nitro-

gen. This finding agrees with the general trendobserved in the groundnut/millet experimentreferred to above (Table 3) and it has importantimplications in practice because it suggests thatintercropping may be more advantageous inlow fertility situations.

This groundnut/maize experiment was fol-lowed by a post rainy season crop of sorghum tostudy the residual effect of sole versus inter-cropped groundnut. The results showed that ifno nitrogen were applied to the groundnut/maize intercrop, there was a beneficial residualeffect on the following sorghum. Where nitro-gen was applied to the maize, however, thegroundnut growth was suppressed and the re-sidual benefit rapidly diminished (Rao et al.1979).

Groundnut/Sorghum Intercropping

In India and Africa, groundnut is very com-monly intercropped with sorghum. Some re-ports have emphasized that significant yield re-ductions of groundnuts have been obtainedwhen they have been intercropped with sor-ghum. John et al. (1943) reported that sorghumdepressed the yield of groundnut by about 50%and Bodade(1964) obtained reductions of 52%.But despite reductions in groundnut yields,there are many reports of overall benefits whenthe yields of both crops are considered.

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Bodade (1964) reported that mixed croppingof sorghum and groundnut gave higher yieldsthan sole cropping and two rows of sorghumwith eight rows of groundnut was one of thebest treatments. Lingegouda et al. (1972) re-ported that three rows of groundnut and onerow of sorghum was more profitable (Rs. 3918/-per ha) than pure sorghum (Rs. 3123/-) or puregroundnut (Rs. 2672/-). A positive benefit wasshown in almost all experimental combinationsof groundnuts with sorghum in East Africa(Evans 1960). Experiments conducted atICRISAT with this combination have given yieldadvantages as high as 38% (Rao and Willey1980) while Tarhalkar and Rao (1979) havereported yield advantages up to 57%.

Groundnut Genotypesfor Groundnut/CerealIntercropping

As in sole cropping, it seems likely thatgroundnut performance in intercropping couldbe improved by identif ication of suitablegenotypes. Indeed it can be argued that the po-tential for genotype improvement could be gre-

a. Mean of 1 trial b. Maan of 2 trials c Mean of 3 trials d. Moan of 4 trials a. Mean of 5 trials

ater in intercropping because of possible in-teractions with the associated cereal crops. Ithas also been emphasized that for crops grow-ing with a more dominant associated crop,there may be particular need for identificationand selection of genotypes within the actualintercrop situation because genotype perfor-mance in intercropping may not be very closelyrelated to genotype performance in sole crop-ping (Willey 1979).

At ICRISAT, studies on the identification ofgroundnut genotypes for intercropping withpearl millet have been carried out since 1977. Todate, results are only available for a relativelyfew genotypes of groundnut, and these havebeen examined in combination with only a fewpearl millet genotypes (Table 4). All studieswere in simple replacement series treatmentsof 3 groundnut rows: 1 pearl millet row. Resultshave indicated that with increasing groundnutmaturity, and the associated change frombunch to runner habit, the groundnut contribu-tion in intercropping (i.e. groundnut LER) tendsto increase (Table 4). This is probably becauseof the increasing time for compensation of thegroundnut after cereal harvest.

However, this increasing groundnut con-

Table 4. The affact of groundnut ganotypa and ganaral typa of millat ganotypa on groundnut LERand total LER in groundnut /pearl millat Intarcropping.

Groundnut Genotypes

1. Chico 2. MH2 3. TMV2

Spanish

4. R33-1 5. MK374 6. M-13

Spanish Valencia

3. TMV2

Spanish Virginia Virginia Virginia Meansbunch dwarf bunch semi- semi- runner (Genotypes

Pearl millet genotypes 85 days 95 days 100 days spreading spreading 130-140 3-6)110 days 125 days days

GAM73/GAM75 g nut LER 0.51* 0.63d 0.72d 0.80c 0.81d 0.74(dwarf, late) Total LER 1.13 1.25 1.22 1.27 1.33 1.27BK560/WC-C75 g nut LER 0.48s 0.48a 0.61e 0.636 0.80c 0.80e 0.71(medium/medium) Total LER 1.03 1.17 1.27 1.23 1.25 1.39 1.29PHB-14/IVSAX75 g nut LER 0.67* 0.70* 0.68* 0.74* 0.70(tall/medium) Total LER 1.09 1.18 1.01 1.28 1.14Ex-Bornu g nut LER 0.90* 0.90* 0.80a 0.90* 0.88(all, late) Total LER 1.25 1.22 1.15 1.28 1.23

Means g nut LER 0.48 0.50 0.70 0.74 0.77 0.81Total LER 1.03 1.15 1.22 1.21 1.17 1.32

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tribution is not so clearly reflected in increasingyield advantages for the combined effect ofboth crops (i.e. total LER); although the latestmaturing groundnut M-13 (130-140 days) wasassociated with the highest mean value for totalLER, there were no real differences in total LERobservable between the three genotypes TMV2(100 days), Robut33-1 (110 days), and MK-374(125 days). There was also little difference ingroundnut or total LER for the different milletgenotypes, though the range of mil letgenotypes was admittedly limited.

In these initial stages of identification, simul-taneous screening of genotypes of both cropswas carried out because there appeared to bescope for selecting more suitable genotypes ofboth crops. No marked interaction betweengenotypes of the two crops has been observedso work is now concentrating on examining a larger number of genotypes of each cropagainst a standard genotype of the other crop.

With the groundnuts, a more detailed study isalso being carried outtodeterminethe extenttowhich the better intercrop performance of thelonger maturing genotypes is due to greatertime for compensation after cereal harvest or tosome other characters which allow bettergrowth and production in the dominated inter-crop situation. In the summer season of 1980,groundnut genotypes were grown with a stan-dard cereal (Sorghum CSH-8); the duration ofcereal competition was examined by removingthesorghum at differenttimes, and the intensityof cereal competition was examined by meansof a treatment in which alternate pairs of sor-ghum leaves were removed. First resultssuggest that increased groundnut contributionwith reduced cereal duration was of the sameorder for all groundnut genotypes and bothlevels of competition. Differences in groundnutperformance were small at a given cereal dura-tion, though there was a tendency for the bunchtypes to do less well than the late runner types.

Groundnut Intercropped withLong Season Annual Crops

No growth studies have been reported for com-binations of groundnuts with any of the longseason annuals. However, it is evident from thegeneral growth patterns of the crops that con-siderable temporal complementarity of growth

occurs. The groundnuts can give reasonablyefficient use of resources during the earlyperiod when the long season annuals are slowto establish; after groundnut harvest, the longseason annuals are able to make use of laterresources, especially of the residual soil mois-ture.

Groundnut/Pigeonpea IntercroppingThis combination is particularly prevalent onred soils of the southern States of India. A common practice here is that if rains commenceat the normal time a groundnut/sorghum orgroundnut/millet intercrop is grown, but if rainsare delayed groundnut/pigeonpea is grown.Pigeonpea rows are usually wide-spaced up to5 m apart with up to 8-10 groundnut rows inbetween. This traditional practice helps to ob-tain high yields of the groundnut cash crop butthe overall advantage of intercropping may notbe high because pigeonpea is too sparsely dis-tributed to make efficient use of late seasonresources and produce a worthwhile yield con-tribution. Most studies have examined this pre-dominantly groundnut situation.

John et al. (1943) reported from a 3-year studythat groundnut/pigeonpea in 8:1 proportionwas 43% more profitable than sole groundnut.Similar results were reported from studies atTindivanam over a 7-year period during 1942-49 (Seshadri et al. 1956). Veeraswamy et al.(1974) and Appadurai et al. (1974) showed thatthe arrangement of 6 groundnut: 1 pigeonpeawas more economical than 8 :1 ; groundnutgave 99% of its sole crop yield and pigeonpea37% of its sole crop yield, totaling an advan-tage of 36%.

At the other extreme, an alternate row ar-rangement at ICRISAT gave an LER of 1.53comprising 95% pigeonpea and 58% ground-nut (Rao and Willey 1980). This may not beideal economically because of the reducedgroundnut contribution, but it illustrates thathigher yield advantages can be obtained withhigher proportions of pigeonpea.

A good compromise situation is indicated bysome studies on five Alfisol locations within IC-RISAT in 1979-80. Pigeonpea was grown in 135cm rows with five very close-spaced rows ofgroundnut between. The population of eachcrop was equivalent to its sole crop optimum.Intercrop yields averaged 82% of groundnut

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and 85% of pigeonpeas, i.e. 67% total advan-tage.

Groundnut/Cotton Intercropping

Joshi and Joshi (1965) reported that a combina-tion of 2-3 rows of groundnut between cottonrows spaced 6 feet apart gave significantlyhigher monetary returns compared to eithersole crop. Varma and Kanke (1969) reported thatgrowing cotton with groundnut was much moreremunerative than growing it alone; yields ofgroundnuts were additional to the cotton yieldsusually obtained. Similar intercropping ofcotton and groundnut has been recommendedfor the northern districts of Madras by NarayanReddy (1961). In the Sudan, Anthony and Wil-mott (1957) also found higher yields fromgroundnut and cotton intercropped together.

Groundnut/Castor Intercropping

Reddy et al. (1965) reported that growing castormixed with groundnut was better than raising a pure crop of castor, and monetary returns were61.9% higher than pure castor. They also re-ported that the yield of castor was more when itwas grown mixed with groundnut compared tocastor grown mixed with greengram, cowpea,Setaria, millet or sorghum. In East Africa, Evansand Sreedharan (1962) showed that there was a clear increase in production when castorbeanand groundnuts were planted together com-pared to sole cropping. Tarhalkar and Rao(1975) reported that intercropping of castor/groundnut gave monetary returns up to Rs 4394per hectare compared with Rs 3317 per hectareobtained from a pure castor crop.

Groundnut/Cassava Intercropping

Introducing an additional crop like groundnutbetween the traditionally wide-spaced cassavaplantings would increase the production ef-ficiency of cassava-planted land as well as con-serving soil moisture and fertility. An experi-ment conducted at Khon Kaen University,Thailand in 1977, produced higher yields of cas-sava (26 756 kg/ha) when intercropped withgroundnuts compared to sole crop of cassava(24 538 kg/ha). The experiment indicated thatpresumably intercropped groundnut increasedthe yield of cassava by supplying additional nit-

rogen from nitrogen fixation. This ground-nut/cassava combination gave around doublethe net income compared with the sole cassavaplanting. Contrary to this, the Department ofAgriculture, Tanganyika (1959) reported thatwhen early sown groundnuts were intercrop-ped with late-planted cassava, the yield ofgroundnuts was not seriously affected, but theyields of cassava were reduced to less thanone-fifth of the sole crop. Potti and Thomas(1978) reported that trials conducted in the far-mers' fields in Kerala, India gave an average of1263 kg/ha of groundnut in addition to the cas-sava yield.

Conclusions

There is good evidence that groundnut/cerealintercropping can give worthwhile yield advan-tages over sole cropping. The ICRISAT studiessuggest that these advantages can be due partlyto more efficient use of light, but further re-search is needed to determine the importanceof this light factor when below-ground re-sources are limiting. The more rapid earlygrowth of the cereals, and the later maturity ofgroundnut compared with the early cereals,may also be an important factor giving somecomplementarity between the crops and allow-ing better use of resources.

Other ICRISAT studies have shown that thelater maturing, semi-spreading or runner typesof groundnut have given the highest groundnutyields in intercropping, but this has not alwaysresulted in improved yield benefits from thewhole system.

Although there has been little detailed workon the intercropping of groundnuts with thelong season annuals, pigeonpea, cotton, castor,and cassava, there is good agronomic evidencethat these systems can give very substantialyield advantages. The general growth patternsof these crops suggest that the main factor re-sponsible for these advantages is that the use ofearly resources by the groundnut complementsthe use of late resources by the longer seasoncrops.

References

AIYER, A. K. Y. N. 1949. Mixed cropping in India. IndianJournal of Agricultural Science 19: 439-543.

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ANTHONY, K. R. M., and WILLIMOTT, S. G. 1957. Cotton

interplanting experiments in the South-West Sudan.Empire Journal of Experimental Agricul ture25: 29-36.

APPADURAI, R., and SELVARAJ, K. V. 1974. A note on

groundnut — redgram mixture in lower BhawaniProject area. Madras Agricultural Journal61: 803-804.

AZAB, Y. E. A. 1968. Pages 5-8 in Applied agronomicresearch on field food crops in Northern Ghana(FAO. No. TA 2596).

DEPARTMENT OF AGRICULTURE, TANGANYIKA. 1959. In-

tercropping. Report of the Department of Agricul-ture, Tanganyika. 11pp.

EVANS, A. C. 1960. Studies of intercropping. I. Maize orsorghum with groundnuts. East African Agriculturaland Forestry Journal 26: 1-10.

EVANS, A. C, and SREEDHARAN, A. 1962. Studies of

intercropping. II. Castorbeans with groundnuts orsoyabean. East African Agricultural and ForestryJournal 28(1): 7-8.

HARDWOOD, R. R., and PRICE, E. C. 1976. Multiple crop-ping in tropical Asia. Pages 11-40 in Multiple crop-ping. Society of Agronomy, Special Publication No.27, Madison, Wisconsin, USA.

JOSHI, S. N., and JOSHI, H. V. 1965. Mixed cropping ofgroundnut/cotton under irrigated conditions inSaurashtra. Indian Oilseeds Journal 9(4): 244-248.

JOHN, C. M., SESHADRI, C. R., and BHAVANI SHANKER

RAO, M. 1943. Mixed cropping of groundnut. MadrasAgricultural Journal 31: 191-200.

KASSAM,A. H. 1976.Pages41-48 in Crops of the WestAfrican Semi-Arid Tropics. ICRISAT, Hyderabad,India.

KHON KAEN UNIVERSITY/FORD CROPPING SYSTEMS PROJECT

ANNUAL REPORT. 1977. Pages 25-39 in Intercropping ofcassava with field crops.

Kou, S. E. 1975. Pure cropping and mixed cropping ofmaize and groundnuts in Ghana. Ghana Journal ofAgricultural Science 8: 23-30.

LING EGO woA, B. K„ SHANTAVEERABADRAIAH, S. M., IN-

AMDAR, S. S., PRITHVIRAJ, and KRISHNAMURTHY, K.

1972. Studies on mixed cropping of groundnut hy-brid and hybrid sorghum. Indian Journal of Ag-ronomy 17(1): 27-29.

MUTSAERS, J. A. 1978. Mixed cropping experiments

with maize and groundnuts. Netherlands Journal ofAgricultural Science 26: 344-353.

NARAYAN REDDY, M. R. 1961. Economics of groundnutand cotton mixtures versus pure groundnut crop inthe northern track of Andhra Pradesh. Andhra Ag-ricultural Journal 8: 66.

OKIGBO, B. N., and GREENLAND, D. J. 1976. Intercrop-

ping systems in tropical Africa. Pages 66-101 inMultiple cropping. American Society of AgronomySpecial publication No. 27, Madison, Wisconsin,USA.

PoTTI, V. S. S., and THOMAS, A. 1.1978. Groundnut as a companion crop in tapioca. In Proceedings of thenational symposium on intercropping of pulsecrops, IARI, New Delhi, July 17-19.

RAO, M. R., AHMED, S., GUNASENA, H. P. M„ and ALCAN-

TARA, A. P. 1979. Multi-locational evaluation of pro-ductivity and stability of some cereal-legume inter-cropping systems: A review of inputs trial III. InProceedings of the Final Inputs Review Meeting,held at Honolulu, Hawaii, Aug 20-24.

RAO, M. R., and WILLEY, R. W. 1980. Preliminarystudies of intercropping combinations based onpigeonpea or sorghum. Experimental Agriculture16: 29-39.

REDDY, G. P., RAO, S. C, and REDDY, R. 1965. Mixed

cropping in castor. Indian Oilseeds Journal9(4): 310-316.

REDDY, M. S., and WILLEY, R. W. 1980. Growth and

resource use studies in an intercrop pearl millet/groundnut. Field Crops Research (In press).

REDDY, M. S., and WILLEY, R. W. 1980. The relative

importance of above and below ground resourceuse in determining yield advantages in pearl millet/groundnut intercropping. Paper presented at thesecond symposium on intercropping in semi-aridareas. Held at University of Dar-es-Salaam, Moro-goro, Tanzania, Aug 4-7.

SESHADRI, C. R., AIYADURAI, J. G., and SRINIVASALU, N.

1956. Groundnut-mixed cropping experiment. Mad-ras Agricultural Journal 43: 496-504.

TARHALKAR, P. P., and RAO, N. G. P. 1975. Changingconcepts and practices of cropping systems. IndianFarming, June 3-7.

VARMA, M. P., and KANKE, M. S. S. 1969. Selection of

intercrops for cotton in India. Experimental Agricul-ture 5: 223-230.

141

VEERASWAMY, R., RATHNASWAMY, R„ and PALANIS-

WAMY, G. A. 1974. Studies in mixed cropping of red -gram and groundnut under irrigation. Madras Ag-ricultural Journal 61: 801-802.

WILLEY, R. W. 1979. Intercropping — Its importanceand research needs. I. Competition and yield advan-tages and II. Research approaches. Field CropAbstracts 32: 2-10 and 73-81.

142

Session 5 — Crop Nutrition and Agronomy

Microbiology

J. S. SainiIn a trial in the Punjab we found that whenwinter wheat was planted either aftergroundnuts, hybrid maize, or local maize wegot better wheat yields after the local maize.This was surprising. What explanation can beoffered?

P. T. C. NambiarIt is difficult to generalize on this. One likelyexplanation is that in this instance, nitrogenwas not limiting. At ICRISAT we have obtaineda 30% yield increase in pearl millet when itfollowed groundnuts.

N. D. DesaiWhen do nodules form and when does fixa-tion commence?

P. T. C. NambiarInitiation varies from season to season. In therainy season they form as soon as 11 daysafter planting. In the postrainy season, theymay not form until 18 days after planting.Nitrogenase activity commences 20 days afterplanting in the rainy season.

P. J. DartThere are large nitrogen reserves in the seedand therefore a shorter dose of nitrogen maynot be needed. Water also limits nodulationand the uptake of nitrate.

D. J. NevillWe heard a lot about host and Rhizobium strain interactions. What about higher orderinteractions such as strain x host x environ-ment interactions? In other words, does a successful combination of strain and hostbehave the same way in North Carolina as itdoes in India?

P. T. C. NambiarWe are doing such trials but we have noresults yet.

J. C. WynneWe are cooperating in these trials withICRISAT. We do not have results yet, but I wouldsuspect that the combinations would bespecific to sites. A lot would depend on thevariety and the photosynthetic activity of thevariety in the different environments.

S. N. NigamIn one of the slides that showed analysis of sev-eral characters, there was no significance fornodule number for the host cultivars. I wouldhave expected that there was a large amountof variability for nodule number, unless veryfew genotypes were in the study. Secondly,regarding the use of plant color in evaluatingfixation by different strains of Rhizobium, thedifferent botanical types of groundnuts them-selves vary in leaf color. Could we say ingeneral that the Virginia types have betternodulation than Valencia and Spanish types?

J. C. WynneThe nodule varies with genotype, and ifenough genotypes are used then significantdifferences are recorded. The results shownwere limited and were not for all the experi-ments we have conducted. We would not useleaf color for selection purposes. When weevaluate strains we use nitrogen-free soils andwe remove the cotyledons also. Color is then a useful parameter for comparison of strains ona single cultivar. Generally in North Carolina,we find that Virginia cultivars are the bestnodulators followed by Spanish and thenValencia botanical types.

R. 0. HammonsNonnodulating lines were found by Dr. G or bet

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Discussion

in Florida and now ICRISAT has isolatedmore nonnodulating types. What use will bemade of these nonnodulating lines?

J. C. WynneI want to produce isogenic lines so we candetermine how much nitrogen is taken upfrom the soil and how much is fixed by theplant. Or. Elkin wants to study the nodulationprocesses.

P. S. ReddyYou say that nodulation is genetically control-led; how many genes are involved?

J. C. WynneDr. Nigam reported yesterday that two reces-sive genes were involved in nonnodulation. Inother processes, quantitative genes are in-volved.

M. V. R. PrasadI have a comment to make rather than a question. We have isolated an EMS-inducedmutant from the TMV-2 cultivar which has a different nodulation pattern. The parent hasmore nodules in the peripheral regions of theroot whereas the mutant has more nodules inthe deeper zones of the root.

A. NarayananDr. Nambiar's results indicated yesterday thatnitrogen fixation occurs in groundnuts duringthe pod filling stages. This is in contrast tomany other legumes in which fixation ceasesduring the reproductive phase.

P. T. C. NambiarWe believe there is genotypic variation in thisphenomenon as far as groundnuts are con-cerned. Some cultivars do continue to fixnitrogen during this stage.

M. A. Ali What are the effects of soil-applied pesticidesand herbicides on rhizobial activity and onother microbes in the soil?

J. C. WynneWe found that in North Carolina some sys-temic insecticides actually increased nodula-tion either directly or indirectly. Some fun-gicides do decrease nodulation.

P. T. C. NambiarIt depends on which chemical is used; wecannot generalize.

P. J. DartIt has been found that if the herbicide affectsthe physiology of the plant then the nodula-tion is affected, but if the plant grows normallythen it is not affected. Not enough work hasbeen done on groundnuts but with Vicia faba, nematocides do not inhibit nodulation.

D. H. SmithIs there mycorrhizal activity in groundnuts andis there any interaction between Rhizobium and the mycorrhiza?

P. J. DartGroundnut is mycorrhizal and some work hasbeen done on this in Bangalore. We hope tostart studies here soon. The big problem isthat the fungus cannot be successfully culti-vated yet. Chopping and applying the roots tothe soil may be a possibility but much morework is needed on this aspect.

V. RagunathanThe method of applying Rhizobium to the seedand then drying the seed in theshadedoes notseem to be very satisfactory. Germinationseems to be affected by this method. What arethe other possibilities?

P. T. C. NambiarWe are experimenting with sand as a carrier atICRISAT and this is placed below the seed atplanting. This is important when seed dres-sings may prevent direct application of in-oculum to the seedcoat due to the danger ofthe seed dressing adversely affecting therhizobia.

P. J. DartIn the USA, the granular inoculum is deliveredthrough a separate tube on the planter and isplaced below the seed. In Australia, soya isinoculated by a liquid inoculum again deli-vered from a separate coulter. At ICRISAT, thefarm machinery section is experimenting withsingle machinery for delivering inoculum.Groundnuts need a large number of rhizobiato effectively nodulate them. Many of thecommercial inoculants in many countries do

144

not meet the required quality and quantitystandard we know are necessary forgroundnut.

Physiology

H. M. IshagWe found that net assimilation rate (NAR) isnegatively correlated with leaf area index (LAI)from sowing to pegging and then there is a steady increase in NAR after pegging. What doyou consider are the reasons for this?

D. E. McCloudI do not like the term NAR and I do not think ithas any physiological significance ingroundnuts. Leaf area increases beyond thetime that full ground cover is achieved. Thetotal canopy photosynthetic rate is more im-portant, and I base my judgment on that.

R. P. ReddyFor your model did you use the temperaturerecorded in the root zone or above groundaround the plant?

D. E. McCloudWe used soil temperature around the peggingzone. We achieved this by using ther-mocouples. We made no attempt to controlthe actual temperature, which fluctuated dur-ing the season, but two of the treatments werewarmer and one was lower than ambient. Theactual figures shown were averaged for theseason.

R. P. ReddyThe length of the podding period varies.Spanish and Valencia have a shorter podfilling period and they should be more efficienttranslocaters.

D. E. McCloudIn our model, potential yields were looked forand we did not take into account pests, dis-eases or drought. Spanish peanuts have a short pod filling phase and have a lower yieldpotential than Virginia types, because only somuch photosynthate is available.

J. GautreauYou have stated that there are two main

factors for pod yield — good partitioning anda longer period for pod filling. I agree butthesecriteria are not valuable everywhere, particu-larly for low rainfall areas. Your criteria relateto areas with assured rainfall or where irriga-tion is available. The haulms are also impor-tant in the SAT for cattle feed, so we must lookfor good foliar growth as well as good produc-tion of pods.

D. E. McCloudThank you for those comments and I agreewith them. Partitioning can go too high andyou can lose flexibility. In fact, in Florida thecultivar Early Bunch is only recommended forthe top growers who can manage their cropwell because this cultivar has a very highpartitioning rate.

M. V. K. SivakumarIs it possible to put soil data into your model?

D. E. McCloudYes, it could be put into our model. Dr. Ducan'sbig computer model in Florida does have thiscapacity.

Intercropping

H. T. StalkerGiven the differences in crop values in bothcash and food value, do you recommend thatthe farmer should intercrop?

M. S. ReddyYes, intercropping is a form of insurance andthere are socioeconomic reasons for it as well.In a dry year there is a good chance that one ofthe crops at least will survive to produce somesort of yield. Farmers are interested becausethere is a compensation effect in the total cropraised.

G. D. PatilDr. Reddy uses the term intercropping, whenhe should be using the term mixed croppingas he is varying the number of rows of themain crop.

M. S. ReddyI disagree. The term mixed cropping is definedas taking more than one crop within a single

145

row. Intercropping is when you grow crops indifferent row proportions. We have used a replacement series technique for cereal/groundnut intercrop experiments. It is impor-tant to consider both crops in varying rownumbers.

C. HarknessFor the peasant farmer, intercropping is veryimportant and there is strong evidence thatthe best use of the growing season is made byadopting this system. In Nigeria, for example,

millet is planted on the first rains and can bereplanted if necessary. This is the early foodcrop for the farmer. When the rains are estab-lished, then groundnuts are planted in thegaps of the millet field. Later, if there are stillgaps, then other quick-maturing species, suchas Voandzeia (groundbeans), can be planted.This system is, of course, not for the large-scale, mechanized farmer. More work isneeded on the pest and disease situation ofthe intercropped groundnut compared to thesole crop groundnut.

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Groundnut Entomology

Chairman: W. Reed Rapporteurs: D. V. R. ReddyP. Subrahmanyam

Session 6

Resistance of Groundnuts to Insects and Mites

W. V. Campbell and J. C. Wynne*

Plants have the ability to repel attack by a myriad of pests. In some instances the level ofresistance may be low, but due to the ability ofthe plant to replace leaves or fruit, the plant willcompensate for damage by the pest and sur-vive. Other plants may posses high resistance,even approaching immunity to a pest. Immu-nity to an insect pest is rare among commerciallyacceptable crops unless the concept of non-host is considered immunity.

Plants with resistance to insects and mitesoffer the most economical method of combat-ing pests. Unfortunately, pest-resistant cul-tivars must be competitive in the market to besuccessful. A pest management approach toinsect control, however, opens the way for useof more germplasm that offers low to moderateresistance to pest complexes. In the search forpest resistance most of the cultivars, breedinglines or species identified as resistant will haveeither low or moderate resistance levels. Lowmoderate or high resistance are relative terms.A plant cultivar with low resistance exhibits lessdamage from a pest than other cultivars grownin the area but may still suffer extensive pestdamage. In general, a groundnut plant with lowresistance may show 10-35% less insect dam-age than the susceptible cultivar, a moderatelyresistant plant may show 35-65% less damage,and a plant with high resistance to an insect willexhibit greater than a 65% reduction in insectdamage compared with the local susceptiblecultivars.

Mechanisms of Resistance

They have been defined by Painter (1951) as

* Professor of Entomology, and Associate Professorof Crop Science, respectively, North Carolina StateUniversity, Raleigh, North Carolina 27650, USA

Note: Paper Number 6617 of the Journal Series ofthe North Carolina Agricultural Research Ser-vice, Raleigh, North Carolina, 27650, USA.

non-preference ( = antixenosis), antibiosis, andtolerance. Plant resistance may be due to anyone mechanism or any combination of thethreemechanisms.

Non-preference is a negative response by a pest to a plant as a source for food, shelter,oviposition or any combination. Those plantcharacteristics that either repel or cause theinsect to leave the host after a brief contact willcontribute to the host possessing a high level ofnon-preference resistance. Characteristics pos-sessed by a plantthat may be mediated throughthe insects sensory system to cause a minordisruption in feeding or oviposition will result inlow resistance by non-preference mechanism.

Antixenosis has been suggested as a substi-tute term for non-preference by Kogan andOrtman (1978).

Antibiosis is an adverse effect of the plant onthe normal metabolism of the insect. Thoseplants that cause higher mortality in any stageof insect development, shorten the life span ofthe adult, or reduce fecundity as compared withknown susceptible plants, are said to possessantibiosis as a mechanism of resistance.

Tolerance is the response of the plant toinsect damage by compensation or replace-ment so that it can support an insect popu-lation that would cause extensive damageto other plants that are considered susceptible.

Painter (1951) used the term pseudoresis-tance to describe a transitory reaction of sus-ceptible plant to environmental stress. He dis-tinguished three types of pseudoresistance:(1) Host evasion is a lack of synchrony betweenplant phenology and pest so that the plant is in a growth stage that is less susceptible to pestdamage when the pest is most abundant;(2) Induced resistance is a temporary resis-tance brought about by some physiologicalchange in the plant in response to soil moistureor soil fertility; (3) Escape is a lack of infestationand damage due to a low pest population orunequal pest distribution. Some insects forexample cause heavy damage on field borders

149

and damage may decrease or become dilutedas the distance into the field increases.

Pseu do resists nce can be inconvenient andtime consuming by causing susceptiblegermplasm to be retested. A retest shouldidentify lines that were selected as resistant butwere actually susceptible due to pseudoresis-tance.

Nature of Resistance

The basis of resistance may be biochemical orbiophysical (morphological). A pest-resistantcultivar may be developed without a knowledgeof the nature of the resistance. For the best useof resources to aid the farmer, resistantgermplasm needs to be identified first, then themechanisms for pest resistance can follow.

Biochemical agents that may be associatedwith resistant plants have been identified formany crops and summarized by Norris andKogan (1980). This research requires the closecooperation of a natural-products chemist, anentomologist with a reliable bioassay method,and a good supply of the pest that is destructiveto the crop. The various chemicals identified asresponsible for resistance include the alkaloids,isoprenoids, aromatics, glycosides, and aceto-genins.

Biophysical characters that have been iden-tified as associated with resistant cultivars in-clude toughness and thickness of leaves, stems,or roots, trichome type, and trichome number.Trichome characteristics have been most oftencited as a morphological character responsiblefor resistance of the host to pest species. It is nowonder that this character has been exploitedoften since it may be observed more readilythan internal characters such as thickness,sclerotization or lignification. Gross mor-phological characteristics of the plant as-sociated with resistance such as plant growthhabit, plant part abnormalities, leaf surfacetexture, size and solidness of stem and shapemay be readily identified with a minimum ofspecial equipment other than hand lens ordissecting microscope.

Observations of discrete differences in leaf,stem or pod thickness, solidness and internalorganization, as well as the presence and loca-tion of lactifers will require histological prepara-tion and staining to differentiate parenchyma

and sclerenchyma. The scanning electron mi-croscope has added an important dimension tothe study of plant surface features that maycontibute to pest resistance or susceptibility.

Methods of Evaluation for PlantResistance to Pests

A number of general methods for evaluation ofgermplasm for pest resistance may be used forvarious pests with slight modification. Fieldmethods, however, will be quite different fromlaboratory or greenhouse methods for selectingpest-resistant germplasm because field testsinvolve multiple plants while laboratory testsusually are limited to individual plants or plantparts. Regardless of whether the evaluation forresistance is conducted in the field or labora-tory, a knowledge of the biology, seasonal his-tory, and damage potential of the pest as well asmethods for maintaining or rearing the testspecies is essential.

Field EvaluationIf the insect pest is so destructive that it causesdeath to the plant, then individual plants thateither survive or exhibit low damage may beselected for retesting. If the experiment isplanted in a randomized block design withsingle or multiple rows, then entries may beevaluated for susceptibility to the pest by count-ing the number of pests, the number of dam-aged plants, the number of damaged leaves,stems, or fruit, or by working outthe percentagedamage to a specific plant part.

Individual plant evaluations for pest resis-tance are desirable for F1 and F2 generationbreeding lines. If seed supply is abundant, it isdesirable to plant more advanced generationmaterial in three-row plots, especially if the pestunder investigation moves readily from row torow. Data then can be collected from the centralrow with the first and third rows acting asbuffers to absorb excess damage from adjacentplots.

Groundnuts attacked by sucking plant pestssuch as the leafhopper or jassid and spidermites may be evaluated for resistance by count-ing the number of pests per plant or number perleaf or number for 5 or 10 leaflets. Resistancerating may also be based on the number or

150

percentage of leaves with leafhopper "hopper-burn" or chlorosis from spider mite feeding(Campbell et al. 1976).

Evaluation of groundnuts for resistance tosoil insects presents a greater challenge. Whenthe insect kills the plant, or causes it to wilt,or causes an abnormal color or size or growthpattern then plants must be dug and sampledfor damage and for the pest. Most soil insectsonly move a few inches in the soil, therefore, a high population of well distributed adults of thepests species is desirableforthe best resistanceratings.

Natural field populations of the pest are oftennot adequate to obtain reliable evaluations forresistance without retesting excessive escapes.Trap cropping with alternate or very susceptiblehosts in or around the field will attract higherpest populations. If this technique does notprovide an adequate pest population, then a limited amount of the most importantgermplasm in the test may be planted in shortrows and covered by a walk-in cage and fol-lowed by the release of a sufficient number ofthe desired pest in the cage (Campbell, unpub-lished).

Greenhouse Evaluat ion

Greenhouse tests are desirable for evaluating a small number of breeding lines or cultivarsintensively where insects or mites are availablein good supply from field sources or rearing.The entire greenhouse may be used as a largecage where a single or a complex of pests maybe released. Most often the plants are caged fora seedling evaluation test for resistance, or leafcages are used to confine a small insect orcolony on selected leaves to study the effect ofthe host plant on the feeding, survival, oroviposition of insects.

Resistance to aphids may be evaluated in thegreenhouse by placing a known number ofaphids on each test plant and then determiningsurvival and rate of reproduction. A knownnumber of insect eggs or larvae of soil pestsmay be placed in the soil of each groundnutcultivar being evaluated for resistance to de-termine insect damage and survival.

Laboratory Evaluation

Initial evaluation of large amounts of germ-

plasm is usually not conducted in thelaboratory due to limited space, excessive timerequired to complete tests, and the need for a strong colony of rapidly reproducing pests.Laboratory evaluation for resistance is mostoften conducted on germplasm that has beenpreviously determined to be resistant in thefield or greenhouse and for which informationon the mechanisms of resistance is desired.

Excised leaves or leaf discs cut with a corkborer from selected lines are often used inpreference to whole plants for space conserva-tion. A susceptible standard must be used in a two choice or multiple choice feeding or ovipo-sition test for nonpreference evaluation. Anothertest should be conducted at the same timecalled a forced feeding or isolation test whereeach plant entry is isolated and separatelyinfested so the pest does not have a choice ofgermplasm for feeding or oviposition.

Plant maturity as well as leaf age on the sameplant has a marked effect on the pest feedingand oviposition. Therefore, all plant partsevaluated for resistance should be collectedfrom plants of the same age and from leaves orfruit on the same position on the plant or sameage. Often mature leaves or mature fruit areunacceptable for food or oviposition regardlessof the plant susceptibility to the pest. Mostinsects prefer the younger, succulent leavesand fruit. There are exceptions, however, suchas stored product pests.

Plastic shoe boxes, sweater boxes or re-frigerator hydrator boxes make suitable cagesfor conducting nonpreference tests. Isolationtests are often conducted in 100 or 150 mmdiameter petri dishes. Known numbers of in-sects are introduced for a period of time, usually1-5 days for evaluation of feeding damage,larval development time, generation time, andreproduction.

Antibiosis studies often conducted in thegreenhouse or laboratory involve isolation ofindividual insects on the plants being evaluatedfor resistance. Measurements are made of suchparameters as larval weight gain, pupal weightor survival, adult weight or survival, or length oftime for insect development. Longevity datamay be appropriate for some pests. Abnormallyhigh pest mortality, poor weight gain, slowdevelopment, or reduced fecundity are all indi-cative of resistance due to an antibiosismechanism.

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Resistance of Groundnutsto Foliage Feeding Insects

Tobacco Thr ips Frankllniella fusca H inds.

It attacks the plant as soon as it cracks theground and causes deformed leaves, smallleaves, stunted plants, and sometimes a delayof several weeks in flowering and pod forma-tion. High populations of thrips will reduce yieldif they attack groundnuts when plants are smalland have only a few terminal leaves (Campbell,unpublished). Some very susceptible breedinglines have been killed by thrips in NorthCarolina.

Field populations of thrips are alwaysadequate for evaluating cultivars and breedinglines for resistance in North Carolina. Ratingsfor resistance have been made by counting thenumber of thrips damaged leaves, or the per-centage of leaves with thrips damage or thepercentage of the leaf area with thrips damage.The varieties NC-GP342 and NC-GP343 as wellas NC-6 (NC-GP343XVA 61R) have low levelresistance to thrips. Susceptible commercialcultivars exhibited two or three times morethrips damaged leaves than resistant lines(Table 1).

Kinzer et al. (1972) developed a rearing method

Table 1. Differences among advanced bread-ing linas in thripv damage. NorthCarolina.

No. thripsdamaged

Identity leavesa

NC-GP 342 85.3Florigiant x AC 342 98.0NC-6 102.0AC 301 x NC-2 130.0NC-GP 343 x Florigiant 136.0

NC-GP 343 146.7NC-GP 343 xNC-5 156.3NC-2 214.0NC-5 273.3Florigiant 285.3Florunner 296.7

LSD (0.05) 58.62

a. per 30 row ft.

for the thrips using an artificial diet that yieldeda higher percentage of adult thrips thangroundnut foliage. This rearing method wouldbe useful for laboratory antibiosis tests andnonpreference studies.

Pota to Leafhopper Empoasca fabae Harr is .

In the USA the potato leafhopper flies northfrom the Gulf Coast region to infest peanuts.Leafhopper populations will vary each year butthe population pressure is sufficiently highevery year in North Carolina to obtain good fieldevaluation for pest resistance.

Since the potato leafhopper causes "hopper-burn," a characteristic V-shaped yellowing onthe apical end of the leaflets, the number ofyellowed leaves, or the percent yellowed leavesor the percent leafhopper damage may becounted or visually estimated for assessingleafhopper resistance. Several North Carolinaaccessions were rated as having high resistanceto the leafhopper. They showed a 99% reduc-tion in damage compared with NC-2 cultivar(Table 2).

During the period since 1960 only a low levelof resistance to thrips has been observedamong the domestic peanutsArachis hypogaea L. However, a number of wild species in sec-tions Rhizomatosae and Arachis appearednearly immunetotobacco thrips and the potatoleafhopper (Table 3). The wild species serve asan untapped reservoir for pest resistance untilthe necessary breeding techniques are de-veloped.

Fall A r m y w o r m Spodoptera frugiperda (J . E. Smi th )

The fall armyworm prefers monocotyledonousplants but they will infest groundnuts whenpopulations are high or suitable grasses are notavailable. Sometimes fall armyworms areattracted to groundnut fields due to excessgrass where they also feed on the groundnutfoliage. The fall armyworm is a migrating,sporadic pest of groundnuts that is more im-portant in the Georgia-Florida-Alabama pro-duction area than in the Virginia-Carolinaregion.

Leuck and Skinner (1971), using laboratory-reared fall armyworms reported adult

152

Table 2. Resistance of groundnut accessions to the potato leafhopper. North Carolina.

AVg. no. leaf- Avg. % leaf-hoppe r damaged hopper damage/

leaves/30 row 30 rowAccession Pedigree* ft. ft.

10207 Recurved x (C12 x C37) 4.0 0.310247 (C12 x C37) x Recurved 10.0 1.010211 (C12 x C37) x Recurved 13.3 0.710277 (C12 x C37) x Recurved 31.7 2.015729 (C12 x A18) M7M5M3M1 42.7 4.015730 (C12 x A18) M7M5M3M1 49.7 3.015745 (C12 x A18) M7M5M1 69.0 3.315744 (C12 x A18) M7M5M1 84.3 5.315736 (C12 x A18) M7M1 92.9 9.315739 (C12 x A18) M7M5M1 97.3 11.710272 (C12 x C37) x Recurved 142.7 10.7

343 C12 x C37 157.7 15.0323 NC 2 493.0 66.7LSD (0.05) 43.0 6.1

a. C12, C37 = NC Bunch x PI 121067; A18 = NC-4 x Spanish 2B; Recurved = irradiation mutant from NC-4.

Table 3. Resistance of wild species of groundnuts to tobac co thrips and potato leafhopper (LH),North Carolina, 1979.

Collectionname PI Collection Section

No. thripsdamagedleavesa

No. LHdamaged

leaves*

A. sp 276233 GK 10596 Rhizomatosae 0 4.0

A. glabrata Benth.

262797 GKP 9830 Rhizomatosae 0.5 0.5

A. macedoi Krap. etGreg, nom nud

276203 GKP 10127 Extranervosae 0 0

A. villosa Benth.

331196 B 22585 Arachis 0 0

A. stenosperma Greg, et Greg.nom nud

338280 HLK 408 Arachis 1.5 0.5

A. batizocae Krap. et Greg.nom nud

298639 K9484 Arachis 0 0

A. monticola Krap. et Rig.

219824 K 7264 Arachis 18.5 0

A. hypogaea NC-6 Arachis 39.0 20.0

A. hypogaea Florigiant Arachis 44.0 57.0

LSD (0.05) 16.17 14.31

a. par 30 row ft.

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emergence was significantly reduced on South-east Runner 56-15 as compared with the sus-ceptible cultivar Starr. They reported PI 196613shortened the life cycle of the fall armyworm by2 days and caused high larval and pupal morta-lity. They concluded the mechanisms of resis-tance were nonpreference or antibiosis.

Corn Earworm Hellothis zea Bodie.

The corn earworm invades groundnut fieldsusually during the peak bloom or fruit produc-tion period. It feeds primarily on the foliagebut also cuts off pegs. Low to moderateresistance to the corn earworm has been ob-served among the North Carolina breedinglines and in Early Bunch and NC-6 cultivars(Table 4). When the moth population is high,field screening for resistance is very successful.Evaluation for resistance may include a visualestimate of earworm defoliation or larvae maybe dislodged from plants with a wood doweland counted on the ground between rows.

A laboratory experiment was conducted todetermine if low H. zea field damage observedon NC-6 cultivars was due to antibiosis. Five,4-day old larvae were isolated on NC-6, NC-2,and Florigiant. In 10 days, larvae fed youngleaves from NC-2 and Florigiant weighed ap-proximately three times more than larvae fedyoung leaves from NC-6 (Table 5). This isevidence that a mechanism of corn earwormresistance in NC-6 is antibiosis.

Table 4. Resistance of groundnuts to the cornearworm (CEW) (Hallothis xeaBodie), North Carolina.

%CEWfoliage

Entry damage

Early Bunch 4.7NC-6 7.3Shulamit 13.0NC-5 13.3Avoca 11 15.0NC-2 18.0Florigiant 19.3

LSD (0.05) 5.48

CV(%) 23.25

Table 6. Antibiosis as a mechanism of resis-tance of NC-6 to the com earworm(CEW), North Carolina.

Cultivar

CEW avg.weight

(g)

NC 6 NC 2 Florigiant

LSD (0.05)

0.01920.05340.0663

0.0208

Spider Mite

Twospotted Spider MiteTetranychus urticae Koch.

The twospotted spider mite causes extensivedamage to groundnuts grown in light, sandysoil that are under drought stress, especiallyfollowing a multiple application of foliage-applied fungicides and insecticides. Due to thehigh reproductive potential and multiple gener-ations within a growing season, there alwaysexists a good possibility of a mite populationshowing resistance to a chemical miticide. Mitepopulations have developed resistance to someorganophosphorus insecticides. There is a needto search for mite resistance in the cultivated andwild species of groundnuts.

Natural infestations of mites are not alwaysdependable; therefore it is desirable to main-tain colonies of mites for field distribution or forlaboratory or greenhouse experiments. Mitesmay be reared on lima bean plants in thelaboratory by inoculating the beans with mites7 days after planting. Lima beans are more suit-able for mass rearing than groundnuts due tothe large amount of foliage produced in a shorttime. Plants may be infested in the field bytransferring two or three bean leaves to thecenter of each entry. Resistance then may bebased on the mite buildup from the releasepoint and measured by counting the number ofmites on a 5 or 10 leaflet sample.

Laboratory or greenhouse experimentsshould be more precise in the number of mitesreleased, for example, the release of onefemale, one pair, 100 eggs, or 50 adults. Thesmaller number would be released on excised

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leaves or leaflets and the larger number onwhole plants.

Representatives of seven sections of thegenus Arachis weretested in the greenhouse inNorth Carolina for resistance to the twospottedspider mite. The highest mite resistance wasfound in the section Rhizomatosae. ResistantRhizomatosae exhibited as much as 90% lessmite damage than the most susceptible entries(Table 6). Leuck and Hammons (1968) alsoreported high resistance among the wildspecies to a closely related mite Tetranychus tumidellus Prichard and Baker. They reportedthat PI 262841 and PI 263396 possessed highresistance.

Soil Insects

sandy soils and most destructive under droughtstress conditions. Loss of young plants mayoccur if the infestation is early or the crop isplanted late. The larvae tunnel into the stems,root, pegs and pods.

Plant introductions were tested in NorthCarolina in single row, replicated plots undernatural field infestations. PI 269116, 269118, and262042 exhibited the lowest damage (Table 7)but there was no evidence of high field resis-tance to the lesser cornstalk borer.

Leuck and Harvey (1968) collected eggs of thelesser cornstalk borer on cheesecloth and arti-ficially infested greenhouse plots of groundnutintroduction with eggs. There was a wide rangein seedling survival but the best plant introduc-tions had 26-29 plants surviving from 30 seedsplanted.

Lesser Corns ta lk BorerElasmopalpus lignosellus (Zeller)

This pest occurs throughout the peanut grow-ing area in the USA and is most abundant in

Southern Corn R o o t w o r mDiabrotlca undecimpunctata howardi Barber

Unlike the lesser cornstalk borer, the rootworm

Table 6. Resistance of wlld spacies of groundnuts to the t wospotted spldar mlte.Graanhousetast,North Carolina, (Johnson at al. 1977).

Collectionname PI Collection Section

% mitedamage8

A. monticola 219824 K 7264 Arachis 96.5a

A. stenosperma Greg, et Greg.nom nud

338279 HLK 408 Arachis 93.5ab

A. hypogaea Florigiant Arachis 83.7a-d

A. hypogaea NC-5 Arachis 72.5cd

A. villosa 331196 B 22585 Arachis 45.0fg

A. sp 276233 GK 10596 Rhizomatosae 24.2h-j

A. correntina Krap. et Greg.nom nud

331194 GKP 9548 Arachis 21.0ij

A. glabrata Benth.

262797 GKP 9830 Rhizomatosae 15.7ij

A. macedoi Krap. et Greg.nom nud

276203 GKP 10127 Extranervosae 15.2ij

A. sp 338317 HLO 335 Rhizomatosae 9.2j

a. Means with the tame letter are not significantly different at the 5% level according to Duncan's Multiple Range Test.

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Table 7. Differences among groundnuts inlesser cornstalk borer damage. NorthCarolina.

No. damagedIdentity pegs + pods"

PI 269116 22.7PI 269118 23.0PI 262042 28.7NC-4 30.0PI 275744 30.7

Schwartz 21 36.7PI 275743 37.3PI 269005 39.3New Mexico Valencia 44.7NC-5 50.7NC-15745 54.0

NC-2 57.0Florigiant 89.0Starr 99.0NC-6 111.3Comet 125.7Florunner 129.3

LSD (0.05) 44.4

CV(%) 41.0

a. per 3 plant sample.

prefers moist, heavy, high organic matter soil ' and cannot tolerate dry sandy soil. The adultrootworm causes minor damage to the termi-nal, unopened leaves but the larvae are capableof destroying ail the pegs and pods. Severerootworm damage occurred in some areas inNorth Carolina when the rootworm developedresistance to a popular insecticide.

In 1960 research was initiated to find root-worm resistant germplasm. Plant introductionsand selections from the North Carolinagermplasm collection were screened in fieldtests. Tests were established in soil with goodmoisture retention properties and generallywith an organic matter content of 1.5-3.5%.Promising lines were tested for 5 years, crossedwith commercial cultivars, and then retestedand selected for 10 more years. In 1976 a cultivar with high resistance to the rootwormwas released as NC-6, a cross between theinsect resistant parent NC-GP 343 and Va 61R(Campbell et al. 1977).

The yield and acre value of NC-6 weresuperior to Florigiant in fields where the root-

worm was a problem and it competed favor-ably in the market for quality and price (Wynne etal. 1977). NC-6 and other accessions with NC-343germplasm exhibit approximately 80% lessrootworm damage than Florigiant (Table 8). Thislevel of resistance is sufficiently high to elimi-nate the need for chemical control of the root-worm in most North Carolina soils.

Table 8. Resistance of groundnuts to thesouthern corn rootworm. NorthCarolina.

No. rootwormAccession damagednumber Identity pegs + podsb

17201 AC 343 X VA61R 10.017167 NC-6a 13.317205 AC 343 x NC-5 18.715973 Florunner 23.017215 NC-5 X VA 61R 34.0

17163 NC-5 x Florigiant 40.3323 NC-2 58.7333 NC-5 69.3348 Florigiant 105.8

17211 NC-5 x Florigiant 108.7

LSD (0.05) 24.4

CV(%) 33.4

a. AC 343 x Va 61Rb. 5 plant sample.

Multiple Insect and MultiplePest Resistance

Cultivar NC-6 is unique in that it possessesmultiple insect resistance. It was developed forhigh rootworm resistance but it also has a lowlevel of resistance to thrips, moderate resis-tance to the potato leafhopper and moderateresistance to the corn earworm. NC-6 is suscep-tible to the lesser cornstalk borer and does notoffer any special advantages against the two-spotted spider mites.

NC-6 has now been crossed with a NorthCarolina breeding line NC-3033 that has resis-tance to Cylindrocladium black rot (CBR), a destructive disease in many fields in theVirginia-Carolina production areas. Some NC-6xNC-3033 progeny have multiple insect resis-tance that is equivalent to NC-6 (Table 9). Selec-

156

Table 9. Evaluation of breeding lines for multiple pest resi stance. North Carolina.

No. thrips No. LHb %damaged damaged CEWC

Entry Identitya leaves/30 ft. leaves/30 ft. damage/30 ft.

13 NC-6 173.3 68.7 1.38 IMC-6 x NC-3033 184.7 95.7 1.74 NC-6 x NC-3033 193.3 43.7 1.36 NC-6 x NC-3033 213.3 45.3 2.7

1 NC-6 x NC-3033 229.7 31.7 1.314 NC-2 334.3 414.7 9.012 Florigiant 493.7 310.0 7.3

LSD (0.05) 71.86 59.27 2.62

a. NC-6 has multiple Insect resistance and NC-3033 Is resistant to Cylindrocladium black rot (CBR).b. Potato leafhopper Empoasca fabae. c. Corn earworm Heliothis zee.

tions are made among the progeny of NC-6xNC-3033 with multiple insect resistance andCBR resistance. The objective is the releaseof a high yielding, multiple pest resistantgroundnut. Care must be exercised to avoid therelease of a cultivar that is resistant to one pestbut very susceptible to other important pests.

Although pest problems differ from countryto country, many of the insects discussed occurworldwide. Closely related species have similarhabits and similar destructive potential. Con-cepts are useful and modification in techniquesmay be needed with specific local populationsand resources.

References

CAMPBELL, W. V., EMERY, D. A., and WYNNE, J. C. 1976.Resistance of peanuts to the potato leafhopper.Peanut Science 3: 40-43.

CAMPBELL, W. V., WYNNE, J. C, EMERY, D. A., andMOZINGO, R. W. 1977. Registration of NC 6 peanuts.Crop Science 17: 346.

JOHNSON, D. R., WYNNE, J. C, and CAMPBELL, W. V.1977. Resistance of wild species of Arachis to thetwospotted spider mite, Tetranychus urticae. Peanut Science 4: 9-11.

KINZER, R. F., YOUNG, SHARON, and WALTON, R. R. 1972.Rearing and testing tobacco thrips in the laboratory

to discover resistance in peanuts. Journal ofEconomic Entomology 65: 782-785.

KOGAN, M„ and ORTMAN, E. E. 1978. Antixenosis — a new term proposed to replace Painter's nonprefer-ence modality of resistance. Entomological Societyof America Bulletin 24.

LEUCK, D. B., and HAMMONS, R. O. 1968. Resistance ofwild peanut plants to the m ite Tetranychus tumidel-lus. Journal of Economic Entomology 61: 687-688.

LEUCK, D. B., and HARVEY, J. E. 1968. Method oflaboratory screening of peanut germplasm for resis-tance to the lesser cornstalk borer. Journal ofEconomic Entomology 61: 583-584.

LEUCK, D. B., and SKINNER, J. L 1971. Resistance ofpeanut foliage influencing fall armyworm control.Journal of Economic Entomology 64: 148-150.

NORRIS, 0. M., and MARCOS KOGAN. 1980. Biochemi-cal and morphological bases of resistance. Pages23-61 in Breeding plants resistant to insects. (F. G.Maxwell and P. R. Jennings, eds.). John Wiley andSons, New York.

PAINTER, R. H. 1951. Insect resistance in crop plants.The Macmillan Co., New York. 520 pp.

WYNNE, J. C, CAMPBELL, W. V., EMERY, D. A, andMOZINGO, R. W. 1977. NC 6, a southern com rootworm-resistant peanut variety. North Carolina AgriculturalExperiment Station Bulletin 458: 15 pp.

157

Groundnut Pest Research at ICRISAT

P. W. Amin and A. B. M o h a m m a d *

Initially research was concentrated on thoseparticular pest problems which were of im-mediate concern at the ICRISAT Center. Simul-taneously, information was collected on themost important pest problems of the crop in theSemi-Arid Tropics (SAT). This paper brieflyreviews the progress made since groundnutpest research started at ICRISAT in late 1977.

Ident i f icat ion of Pest Problems

Groundnut Pests at ICRISATAt ICRISAT the insect fauna from groundnutswas collected from 1 0 x 1 0 meter sized plots ofthree cultivars with erect bunch (cv TMV-2),spreading bunch (cv Robut 33-1), and runner(cv M-13) growth habits replicated three timesin pesticide-free and pesticide-affected areas.Over 70 insect and other pests of ground-nuts were collected.

The seasonal abundance of the various in-sects was also studied in plots of the groundnutcv TMV-2 raised at several locations on bothAlfisols and Vertisols on the ICRISAT farm. Thecrops were sown monthly from June throughFebruary, individual plots being sited at least400 m away from other groundnuts. Informa-tion on the abundance of insects in relation tolocations, soil types, pesticide-free or affectedareas, seasons, and years was recorded.

Termites and wlreworms were most abun-dant in Alfisols while earwigs and millipedeswere more abundant in Vertisols. In Vertisolsleaf miner was more prevalent in some loca-tions than others. Thrips injury was more pro-nounced windward than leeward locations.Barriers across the prevailing winds affectedthrips distribution; smaller numbers of thripswere observed on the plants in the vicinity offield bunds to the leeward side. Some insects

* Entomologists, Groundnut Improvement Program,ICRISAT.

became more abundant in drought years;Caliothrips indicus, leaf miner, Aproaerema modicella, and aphid Aphis craccivora weremore abu ndant in th e drought year of 1979 th anin the good rainfall year of 1978. In normalyears, insects such as thrips (Scirtothrips dor-salis and Frankliniella schultzei) were abundantin both rainy and postrainy seasons, Spodopt-era litura and Aproaerema modicella in thepostrainy season, Aphis craccivora in the sum-mer season, and Empoasca kerri in the rainyseason. Heliothis armigera was an importantflower feeder in both rainy and postrainy sea-sons. (Fig. 1).

Groundnut Pests in India

In India insect pests are major constraints onyields, being particularly important in the statesof Andhra Pradesh, Tamil Nadu, Punjab, Rajas-than, Gujarat and Maharashtra. About two de-cades ago, only a few insects were regarded asimportant pests (Rai 1976) but the situation haschanged considerably. Insects like Spodoptera litura, Frankliniella schultzei, Scirtothrips dor-salis and Empoasca kerri which were not consi-dered important pests then, are now so recog-nized (Table 1).

Insects such as leaf miner have been spread-ing and considerable damage by this insect wasreported for thefirstt imefrom Gujarat and fromthe Dhuliadistrict of Maharashtra in 1978. Whitegrubs (Lachnosterna consanguinea) have com-pelled many farmers to abandon groundnutcultivation in sandy soils of Gujarat, Rajasthan,Uttar Pradesh, and Punjab.

Groundnut Pests in SATOn the world scene, over 300 species of insectpests have been recorded from groundnuts butonly a few are important worldwide and a fewothers in restricted regions (Table 2). Some areimportant as vectors of viral diseases (Table 3).Insects are important as quality reducers and

158

FrankliniellaSchultzei perterminal leaf

Scirtoth rips dorsalis perterminal leaf

Empoasca kerri per three terminalleaves

Stomopteryxsubsecivella minesper plant

Hefiothis armigera and Spodoptera litura larvae per plant

Figure 7. Major pests of groundnut at ICRISAT and their seasonal distribution.

there are many storage pests against whichstrict quarantine is in vogue, e.g., Caryedon serratus, Trogoderma granarium. The literatureon groundnut insects from Commonwealthcountries has been reviewed by Feakin (1973),for the USA by Bass and Arant (1973), and briefreview of world pests by McDonald and Raheja(1980).

Studies on the Thrips Vectorsof Bud Necrosis Disease

Thrips-borne bud necrosis disease caused bytomato spotted wilt virus is an important dis-ease in India (Table 4) and ICRISAT (Table 5). A higher incidence was observed in the rainyseason than in the postrainy season. A majorepiphytotic occurred in 1979 when the infectionlevel in unsprayed crops reached 80-95%.In the subsequent postrainy season lessthan 30% infection was recorded in un-sprayed plots. Infection levels were lowest incrops sown in September and October and fromFebruary - May.

Table 1. Major pasts of groundnut in India.

Year 1968a Year 1979b

1. Aphis craccivora 1. Lachnosterna consangumea

2. Aproaerema modicella 2. Aphis craccivora {Stomopteryxsubsecivella)

3. Amsacta spp 3. Aproaerema modicella [Stomopteryxsubsecivella)

4. Microtermes sp and 4. Amsacta albistriga Odontotermes sp

5. Heliothis armigera 6. Spodopetera litura 7. Frankliniella schultzei 8. Scirtothrips dorsalis 9. Empoasca kerri

10. Odontotermes obesus 11. Pod scarifying termites

a. Rai, B. K. 1976. Pests of oilseed crops In India and theircontrol. Indian Council of Agricultural Research, NewDelhi.

b. From field trips, literature, and correspondence.

159

Table 2. Major Arthropod pesta of groundnut. a

Regions where serious

Asia Africa Americas* Australia

Sucking Aphis craccivora Aphis craccivora pests Empoasca kerri Empoasca dolichi Empoasca Austrasca sp

Scirtothripsdorsalis

Frankliniellaschulaei

Caliothripsindicus

Empoasca facialis fabae

Ennoethripsflavens

Frankliniellafusca

Paraplobia sp

Foliage Spodoptera Spodoptera Spodoptera Spodopterafeeders litura littoralis fungiperda litura

Heliothis Heliothis zea Heliothisarmigera

Aproaeremamodicella

Amsacta spp

Feltiasubterranea

Anticarsiagemmatilis

armigera

Root feeders Lachnosterna sp Hildapetruelis

Rhopaeamagnicornis

Odontotermes sp Microtermesthoracalus

Heteronyx sp

Pod feeders Microtermes sp Microtermes sp DiabroticaEtiella Elasmolomus undecim-zinckenella sordidus punctata

Elasmolomus Peridontopyge Pangeassordidus sp.

Caryedonserratus

bilineatus

a. Feakin, S. D. 1973. Pest control in groundnut, PANS Manual No. 2. COPR, London.b. Mainly from Bass, M. H. and Aran!, F. S. 1973. Pages 383-428 In Peanuts-culture and uses.

The epiphytotics of the disease were as-sociated with an abundance of the major vectorFrankliniella schultzei. Investigations over thelast three years have given some useful infor-mation:

1. The major vector, Frankliniella schultzei isa polyphagous thrips species. Populations ofthese thrips are lowest during summermonths when they survive mainly in flowersof wild plants, cultivated summer crops, andornamentals. Cassia sp, Ageratum con-yzoides, Tridax sp, Tribulus sp, and Calltropis sp are some of the important weeds thatharbor F. schultzei while greengram, blackgram, and cowpea are important crop hosts,and marigold and chrysanthemums are im-

portant ornamentals. The thrips migrate tothe crops which are sown early or to theweeds particularly Cassia sp and Ageratum sp that emerge soon after the first few mon-soon showers. The populations build up onthese hosts.2. Migrations to groundnuts take placethroughout the season but the large scalemigrations occur in August and January. Thethrips are carried on the prevailing winds andmainly at dusk. The disease infection is as-sociated with immigrant thrips and secon-dary spread is not important Crops sownearly largely escape from the disease (Fig. 2).The number of immigrant thrips is indepen-dent of the number of plants per unit area. A

160

higher plant stand results in a proportionaldecrease in the percentage of infected plants.3. Early infection can lead to a total yield loss.

Infection during flowering and peggingstages results in substantial reduction in thenumbers of flowers produced, the duration of

Table 3. Insect vactors of virus/mycoplasma diseases of g roundnut. a

Diseases Vectors Regions

Rosette Aphis craccivora African continentPeanut spotted wilt* Thrips tabaci Brazil, South Africa

and AustraliaBud necrosisb Frankliniellac

schultzeiIndia

Yellow spot Scirtothrips dorsalisc IndiaPeanut mottle Aphis craccivora USA, China, MalaysiaPeanut stunt Aphis craccivora USAWitches' broom Orosius sp Indonesia, JavaRugose leaf curl Not known AustraliaMarginal chlorosis Not known Papua New Guinea

a. Feakin, S. D. 1973. Pest control in groundnut, PANSManual No. 2. pp.197 - Centre for Overseas Pest Research, London.b. Caused by tomato spotted wilt virus.c. Amin, unpublished.

Table 4. Bud necrosis disease incidence on groundnut crop s in India."

Percent diseaseStates Region incidence Year

Andhra Pradesh Hyderabad 50-60 197850-90 1979

Coastal 0-5 1978Central 0-20 1979

Karnataka Eastern 0-2 1978Southern 0-2 1978

Maharashtra Eastern 0-5 19770-5 19780-5 1979

Western 0-5 197720-50 1980

Punjab 2-10 1977

Uttar Pradesh Western 10-25 197840-50 1979

0-5 1980

Tamil Nadu Western 15-20 1978

Gujarat Saurashtra 0-10 19770-5 19790-5 1980

North Eastern 0-5 197720-60 1980

a. Estimates from field trips of Groundnut Program scientists of ICRISAT.

161

Date of observation

Figure 2. Effect of sowing dates on bud necrosis disease incidence, rainy season 1979.

Table 5. Incidence of bud necrosis disease ongroundnut at ICRISAT Center. a

Table 6. Bud necrosis disease incidence instandard cultivars during differentseasons in unsprayed plots.

a. Figures for unpro tec ted p lots.

the flowering period, peg length, and podgrowth. Infection in the late stages reducesyield but to a lesser extent than does earlyinfection.4. Some cultivars appear less susceptiblethan others to field infection by the disease.Robut 33-1 is one such cultivar; it has a highyield potential and is commercially accept-able (Table 6).5. Insecticides are generally not effective inreducing the disease incidence, unless

applied twice a week throughout the season.Insecticide applications during thrips immig-ration, requiring 3-4 sprays, is as effective as12 sprays applied at weekly intervals throughthe cropping season.Based on the above findings, a combination

of cultural and insecticidal methods was re-commended to reduce damage from the dis-ease. This consisted of: (1) early sowing (about6 weeks before mass immigration of thrips), (2)higher plant density, (3) use of less susceptiblecultivars, and (4) use of insecticides during

162

Percentdisease

Year Season incidence

1977 Rainy 50-60Postrainy 45-56



1980 Rainy 80-90

Percent disease Incidence

Season TMV-2 Robut 33 -1 M-13

Rainy 1978s

Postrainy 1978*Rainy 1979*Postrainy 1979c

Rainy 1980b

86.848.5

100.034.493.8

33.628.250.220.535.3

60.637.057.127.840.8

a. Nonreplicated plotsb. 3 replicationsc. 4 replications

thrips immigration. When all these practices arefollowed, substantial reductions in disease areobtained (Table 7).

Screening Germplasmfor Pest Resistance

Four insects which are important worldwideand also occur at ICRISAT were selected forscreening. The general screening procedure andobjectives are given in Figure 3. The insectswere thrips (Frankliniella schultzei), jassids(Empoasca kerri), and termites which causedpod scarification. Screening against aphidsAphis craccivora was done in the glasshousebecause populations of aphids were not highenough in the field, except during June and theearly part of July.

Thrips

Frankliniella schultzei infestation resulted in a scarring of foliage and distortion of leaf mar-gins. An injury rating scale of 1-9 was used ininitial trials (1 = n o injury; 9 = distortion ofmargins). Promising lines were advanced andselections were made by visual scoring. Thelower susceptibility of some of these lines andwiId Arachis sp was confirmed in the laboratoryby studying the fecundity of thrips (Tables 8a,8b). Some ofthe promising lines have been sentto the USA and Brazil for further testing whereFrankliniella fusca and Enneothrips flavens areimportant thrips pests.

JassidsThe major jassid pests of worldwide impor-

Table 7. Effect of various cultural practices and insecticldal regimes on the incidence of budnecrosis disease.

Basis forSowing Plant density insecticide* Percent diseasedate (000/ha, approx) Cultivar treatment incidence

120

Robut 33-1 (T) Thrips invasion*Weekly schedule

28.523.9

TMV-2(S) Thrips invasion 57.2Early Weekly schedule 60.4(15June)

80

Robut 33-1(T) Thrips invasionWeekly schedule

36.132.1

TMV-2(S) Thrips invasionWeekly schedule

83.581.3

120

Robut 33-KT) Thrips invasionWeekly schedule

48.059.8

TMV-2(S) Thrips invasion 92.5Normal Weekly schedule 94.2(15July)

80

Robut 33-KT) Thrips invasionWeekly schedule

51.149.9

TMV-2(S) Thrips invasionWeekly schedule

92.894.8

T. Cultivar with tolerance to virusS - Cultivar susceptible to virusa. Dimetheate 400 ml/hab. Based on thrips catches In suction trap.

163

Figure 3. Basic scheme for identification and utilization of multiple pest resistanceltolerance.

Table 8a. Fecundity of Franklinlella achultzai on some cultivars of groundnut.

Cultivar No. eggs/female

NC Acc 2243NC Acc 2232NC Acc 2214TMV-2

4.04.88.5

15.0

Table 8b. Fecundity of Franklinlalla schulttml on different Arachis species.

SpeciesNo. eggs laid by

10 females in 24 hours

A. chacoense A. glabrata A duranensls A. hypogaea (cv TMV-2)

004

44

tance belong to the genus Empoasca. In Indiaand at ICRISAT, Empoasca kerri is the dominantspecies. Jassid injury results in tip yellowingand tip burn. Initial evaluations were done onthe basis of the number of leaflets showinginjury in 100 randomly collected leaflets, andsubsequent evaluations by counting thenumber of jassid nymphs on three terminalleaves of 10 plants of individual accessions.Some promising lines with resistance to jassidsare given in Table 9.

Recently, it has been observed that Empoasca kerri nymphs and adults cause irreversible wilt-ing in seedlings. Further laboratory screeningtrials are planned.

AphidsIn preliminary glasshouse trials, five pottedplants of each accession were subjected to highaphid attack by placing them near aphid-infested

164

Table 9. Some promising germplasm against Empoasca karri.

Growth Average no ofCultivar habit jassid nymphsa Range* Susceptibility

NC Acc 2214 Runner 2 0-5 R" 2232 " 3 2-6 R" 2243 " 5 3-13 R" 2240 " 5 1-8 R" 2242 " 5 3-10 R

" 343 " 13 9-20 MRM-13 " 19 10-43 SNC Acc 2462 Spreading bunch 15 10-19 MR

" 2477 " " 14 10-17 MRRobut 33-1 " " 39 17-41 S

NC Acc 2663 Erect bunch 17 12-25 MR" 2888 " " 15 9-20 MR" 406 " " 14 5-19 MR" 489 " " 15 11-18 MR

TMV-2 " " 31 15-57 S

a. Nymphs were counted from three terminal leaves each from ten plants. Average for three replications.b. Number of nymphs per ten plants.B = Resistant, MR - Moderately resistant, and S = Susceptible.

plants. The accessions showing more than 25aphids per plant were rejected. The same pro-cedure was applied to wild relatives of Arachis. One accession and several wild species thatshowed promise were tested in the laboratory.The results are shown in Table 10.

Termites

At ICRISAT, pod scarifying termites (species notidentified) occur in pesticide-free Alfisols. A one-

hectare plot where the termite population washigh was set aside for screening. Termite build-up was encouraged by avoiding the use ofpesticides and deep cultivation, and by supply-ing bamboo pegs for food during off seasons.The distribution of termites was studied bydistributing bamboo pegs throughout the plot.Many pegs were attacked indicating a fairlyuniform distribution of termites. The scarifica-tion of pods was studied in pods attached toplants as well as in detached pods. The

Table 10. Number of progeny produced by Aphis cracclvora on the detached shoots of twocultivars of Arachis hypogaaa and Arachis chacoansa.

Total no.Totalno. of

Cultivars/ No. of of adults nymphs Nymphs/wild species trials used produced female

A. chacoensea 9 92 30 0.3A. hypogaea:

NC Acc 2214(8) 4 54 61 1.1NC Acc 2214(7) 15 143 319 3.2TMV-2b 10 94 1308 14.0

a. Resistant checkb. Susceptible check

165

technique of testing detached pods has beenfurther improved by baiting the pods with a cowdung slurry which attracts termites. Suchpods are buried near the bamboo pegs thathave been attacked by termites. Some cultivarshad much less termite damage than others. A few lines that showed very low damage for twoseasons are being further tested.

ReferencesBASS, M. H., and ARANT, F. S. 1973. Peanuts — culture

and uses. Pages 383-428 American Peanut Re-

search Education Association. Stone Printing Co.,Virginia, USA.

FEAKIN, S. D. (ed.) 1973. Pest control in groundnuts.PANS Manual No. 2, Centre for the Overseas PestResearch, London.

MCDONALD, D., and RAHEJA, A. K. 1980. Advances inlegume science. (Summerfield and Bunting eds.)./nThe Proceedings of the International Legume Con-ference, Kew, England, 31 July-4 August 1978.

RAI, B. K. 1976. Pests of oilseed crops in India and theircontrol. Indian Council of Agricultural Research,New Delhi.

168

Session 6 — Groundnut Entomology

Discussion

M. V. R. PrasadYou have mentioned that the number ofsprays for controlling bud necrosis diseasewere reduced from 16 to 4. How did youachieve this? How it is applicable to the far-mers?

P. W. AminThis was done by monitoring thrips usingsuction traps and applying the insecticidalsprays during thrips migration. Earlier wewere using a fixed schedule of weekly sprays,and thus up to 16 sprays were applied. How-ever, it is difficult for farmers to know when thethrips are invading the crop. Thus it is advis-able to follow early sowing and to use lesssusceptible cultivars.

S. M. MisariYou have mentioned that pegs were alsoinfested by aphids. What effect does this haveon pegs?

P. W. AminUsually aphids infest groundnuts in lateAugust and on an average seem to cause 15%damage through desapping of plants andaffecting the growth.

S. M. MisariWhat is the nature of damage? Are the ovariesaborted due to aphid infestation or the podformation occurs but leads to decreased shel-ling percentage?

P. W. AminThis has not been specifically investigated.

N. D. DesaiDo you have any program for screeninggermplasm for resistance against whitegrubs? And can you suggest any good chemi-cal control for white grubs?

P. W. AminGroundnut crop at ICRISAT is not infested bywhite grubs and therefore we are not workingin this area yet. But, several scientists in Indiaare working on the control of white grubs.

D. R. C. BakhetiaWe have been working on the control of whitegrubs in Punjab. We found that the applicationof granular insecticides such as isofenphosand carbofuran was very effective.

P. W. AminWhite grubs are polyphagous and it may bedifficult to find sources of absolute resistance.However, it should be examined.

D. R. C. BakhetiaIn the screening trials the criterion that youhave used, percent plant damage, to assessthe resistance of a cultivar may not be veryaccurate. Is it necessary to take into consider-ation the different levels of damage underspecific environmental conditions?

W. V. CampbellIt is important to use the extent of damage as a criterion because it shows a sum total of allfactors, e.g., insect number, cultivar, en-vironment, etc.

T. P. YadavYou rely mainly on natural infestation forscreening. Is it acceptable?

P. W. AminWe do prefer screening under field conditions;however, we also do laboratory testing forlocating sources of resistance as in the case ofaphids.

W. ReedAssessment of damage in the field is a straightforward and reliable criterion.

167

Session 7

Groundnut Pathology

Rapporteurs: I. S. CampbellA. B. MohammadD. J. NevillA. K. Singh

Chairman: J. S. Chohan

Cylindrocladium Black Rot (CBR)Disease of Peanut (Arachis hypogaea)

Marvin K. Beute*

Cylindrocladium black rot (CBR) of peanut[Arachis hypogaea L.) caused by Calonectria crotalariae (Loos) Bell & Sobers (Cylindro-cladium crotalariae [Loos] Bell & Sobers), wasfirst described as occurring in Georgia, USA in1965 (Bell and Sobers 1966). It was reported tooccur in South Carolina in 1968 (Garren et al.1972) and North Carolina and Virginia in 1970(Garren et al. 1971, Rowe et al. 1973). CBR wasfound on peanut in Japan in 1970 and wassubsequently regarded as a major disease ofpeanut in 1971 (Misonou 1973). Although CBRnow occurs in certain areas of Alabama andFlorida as well as Georgia and South Carolina,CBR is only considered a disease of seriouseconomic importance in the USA in NorthCarolina and Virginia.

The effect of CBR on peanut is reported tovary from debilitative to destructive dependingon host resistance, environmental conditions,and inoculum density in soil. First symptoms ofCBR in the field ranged from chlorotic, stuntedplants to slight wilting of larger plants (Rowe etal. 1973). In newly infested fields symptomswere usually confined to one or several irregu-lar areas within a field. In fields with a priorhistory of CBR, diseased plants were evenlydistributed, giving a ragged appearance to anentire field. Tap roots of chlorotic, stuntedplants were severely blackened and usuallysevered by decay at the junction of thehypocotyl and tap root, approximately 4-6 cmbelow the soil surface. Lateral roots on suscep-

* Professor of Plant Pathology, North Carolina StateUniversity, Raleigh, North Carolina 27650, USA.Paper Number 6621 of the Journal Series of theNorth Carolina Agricultural Research Service,Raleigh, North Carolina, USA.The use of trade names in this publication does notimply endorsement by the North Carolina Agricul-tural Research Service of the products named, norcriticism of similar ones not mentioned.

tible peanuts were either blackened or com-pletely severed 1-2 cm from the tap root.Diagnosis of CBR was aided by the abundantproduction of red perithecia which occur at thebase of infected stems under moist conditionsin fields. In areas under drought stress or infields with severely stunted plants, peritheciawere observed sparingly, if at all. Peritheciawere found on intact stems, pegs, and pods onand under the soil surface, but never on decay-ing plant debris in proximity to infected tissues.

Extensive efforts to develop chemical controlfor CBR have not been productive (Rowe et al.1974). Resistance to CBR in peanut genotypeswas reported in 1975 (Wynne et al. 1975), butprogress in development of resistant cultivarswas initially hampered by lack of knowledgeconcerning the biology of C. crotalariae andepidemiological aspects of the disease.

Biology

Fungus Reproduct ion

C crotalariae produced conidia, ascosporesand microsclerotia (ms) in culture and infectedplants (Jackson and Bell 1969). Conidia wererarely observed under field conditions but werecapable of causing necrosis of roots and pods ofpeanut (Beute and Rowe 1973). Conidia werenot considered to be important in the spread ofCBR because of their infrequent occurrence inthe field and limited viability due to a highsusceptibility to desiccation.

Perithecia of C. crotalariae were reported toform abundantly on infected stems, pegs, pods,and hypocotyls of peanut at the soil line ifsufficient moisture was present (Rowe andBeute 1975). Under high moisture conditionsascospores could be detected in the field oozingfrom 2-3 week old perithecia in a cream tobright yellow, viscous droplet that clings to thetip of each perithecium. Spores discharged in

171

this manner were presumably dispersed byrain-splashing.

In histological studies of inoculated peanutstems, perithecia with a few nearly mature asciwere observed after 13 days and fully matureasci containing mature ascospores were com-monly observed 2-3 weeks after inoculation.Ascospores were forcibly ejected from a singleperithecium for 2-3 weeks after maturity, priorto being exuded in a viscous ooze. Develop-ment and discharge of ascospores seemed tobe more closely related to water relations of thefungus than to temperature. Viability of ascos-pores was similar to conidia, i.e., they wereextremely sensitive to desiccation. The mostlikely role of ascospores in CBR epidemiologywas suggested to be short-distance, within-fieldspread of the disease.

C. crotalariae was shown to producemicrosclerotia (average size = 53 x 88 µm)abundantly in decaying peanut tissue. Mic-rosclerotia (ms) first appeared in infected roots55 days after inoculation in the field and num-bers increased rapidly after 90 days (Rowe et al.1974); Microsclerotia formed within CBR-in-fected peanut roots were shown to be effectivelong term survival propagules. As disintegra-tion of root tissues progresses, the propagulesare released into the soil, and spread locallyduring tillage and aqueous runoff (Krigsvold etal. 1977). Aerial dissemination of ms of C.crotalariae in windblown plant parts was ob-served. Root fragments containing ms werefound in debris expelled from peanut combinesoperating in infested fields in North Carolina.Fragments large enough to carry microsclerotiawere trapped 225 m downwind from combineson relatively calm days. Although it was con-sidered unlikely that airborne ms could explainthe apparent rapid spread of CBR across thesoutheastern United States, once the fungushas become established in a locality, airbornems could be effective in regional dispersal.

In fec t ion Process

Early stages of pathogenesis of peanut by C.crotalariae involved the formation of infectioncushions on the epidermis, followed by com-plete hyphal colonization of the cortex(Johnston and Beute 1975). Collapse of theepidermal cells beneath infection cushions andnecrosis of surrounding cortical cells appeared

to be a prerequisite for fungal invasion,suggesting the possible involvement of phyto-toxins. Natural periderm formation appeared toeffectively limit C. crotalariae growth to thecortex under certain circumstances and plantswith only cortical decay were capable of re-covery.

A histological study on the nature of resis-tance to CBR in peanut germplasm suggestedthe involvement of efficient formation of addi-tional effective periderms in the resistancemechanism(s). Susceptible peanut cultivarssustained more breachments of the originalperiderm per length of taproot tissue than didresistant lines. Susceptible cultivars were alsoless efficient in formation of additional(walling-off) periderms than resistant lines, andthe additional periderms were ultimately lesseffective. Resistant lines were observed toinitiate phellogen in the pith and essentiallyslough an entire quadrant of infected taproot.Emerging fibrous roots disrupted the protectiveperiderm cylinder of the peanut taproot andprovided favorable infection courts of the fun-gus. Primary branch roots of resistantgenotypes were capable of periderm formationwhen infected by C. crotalariae. No peridermwas observed in fibrous roots of susceptiblecultivars. Microsclerotia were found only in thecortex of necrotic taproot and fibrous roots.

Host Renge

All legumes tested to date appear to be hosts forC crotalariae (Mesonou 1973). A partial list ofsusceptible hosts included peanut, clover, al-falfa, Crotalaria, soybean, lupine, bean, andpea. Considerable variability in susceptibilitywas reported to exist between host species, e.g.soybean was much more resistant to C.crotalariae than was peanut. Certain non-leguminous crops (tobacco and cotton) nor-mally included in peanut rotations in NorthCarolina have also been shown to be suscepti-ble to C. crotalariae when grown in fumigatedsoil in greenhouse tests (Rowe and Beute 1973),but no increase in inoculum occurred underfield conditions (Phipps and Beute 1979). Cornand small grains appeared highly resistant to C.crotalariae and should be useful as rotationalcrops in infested fields to minimize inoculumincrease (Phipps and Beute 1979; Rowe andBeute 1973).

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Inoculum QuantificationTechniques

Isolation Procedure

Development of a semi-selective isolationmedium was essential for the study of theecology of soilborne pathogens. Repeated at-tempts to quantify ms from peanut soil usingprocedure and medium reported for quantita-tive isolation of other Cylindrocladium specieswere unsuccessful. Phipps et al. (1976) de-veloped the following medium for use with theelutriation procedure described below:

Basal constituents of the isolation mediumincluded glucose, 15 g; yeast extract, 0.5 g;KNOa, 0.5 g; KH2PO4,1.0g;MgSC<4.7H2O, 0.5g; agar, 20 g; and deionized water, 1 liter.After autoclaving, 200 ml aliquots of themedium were amended with Tergitol NP-10(Union Carbide, Atlanta, Ga.), 0.21 ml;thiabendazole, 0.2 mg; chloramphenicol, 20mg; and chlorotetracycline, 8 mg. Tergitolwas added directly to the medium, whereasthe following amounts of the other agentswere added from stock solutions: thiaben-dazole (16.6 mg of 60% wettable powderformation suspended in 50 ml water), 1 ml;chlorotetracycline (0.4 g dissolved in 50 ml50% ethanol), 1 ml. Tergitol was used tosuppress growth of fungi (Krigsvold et al.1977) and lower the surface tension of themedium which permitted the pouring of a thin agar layer in each plate. Thiabendazoleserved primarily to inhibit growth by certainundesired fungi (Hadley et al. 1979), and theantibacterial compounds, chloramphenicoland chlorotetracycline, prevented develop-ment of bacterial colonies.Plant debris larger than 425 µm and organic

matter 38-425 µm were eluted from soil andcollected on 425 µm (35 mesh) and 38 µm (400mesh) sieves, respectively, using a semiautomatic elutriator designed for extract-ing nematodes from soil (Byrd et al. 1976). Plantdebris collected on the 425 µm sieve wasblended for 2 minutes in 200 ml of water torelease bound ms. Each fraction was exposedfor 1 minute to 0.25% NaCIO prior to enumera-tion using a selective medium. Both fractionswere suspended in approximately 160 ml ofwater using a mechanical stirrer. Quantitativeassays for ms in the suspended fractions were

made by pipetting 5 ml subsamples into 100 mlof test media at 47°C. The media was thenswirled immediately and dispensed into 10 petridishes. Plates were incubated under continuouslight at room temperature (25-28°C) untilcolonies developed (5-8 days) and readingswere taken.

An alternativeCBR medium wasdeveloped inVirginia to be used with a wet sieving proceduresimilar to that of Krigsvold and Griffin (1975).The new selective medium (Griffin 1977), de-signated sucrose-QT medium had thefollowingcomposition: 70 g of sucrose (to give an osmoticpotential of about-10 bars), 0.4 g of DL-tyrosine,1 g KH2PO4, 0.5 g of MgSC47H2O, 50 mg ofstreptomycin sulfate, 50 mg of chlorotetracyc-line HCI, 4 g oxgall, 75 mg of pentachloronit-robenzene (PCNB), 2.3 mg of 2-(4-thiazolyl)-benzimidazole (thiabendazole, TBZ), 750 mg ofdimethyldicoco ammonium chloride (added as1.0 ml of Adogen 462, Ashland Chemical Co.,Columbus, OH), 400 mg of methyldo-decylbenzyltrimethyl ammonium chloride, 100mg of methyldodecylxylenebis (trimethyl am-monium chloride), added as 1.0 ml of Hyamine2389, a mixture of the two quaternary am-monium compounds (Rohm and Haas Co.,Philadelphia, PA), 20 g of agar, and 1 liter ofwater. The medium was adjusted to pH 4.0.

Environmental Effects

Field observations in Georgia indicated thatCBR was most severe under conditions of ex-cessively high soil moisture followed by ex-treme moisture stress to infected peanuts, bothwith concomitant high soil temperature (Bell1967). Inoculation tests in North Carolina underthese conditions were inconsistent, suggestingthat both moisture and temperature could belimiting factors in disease development. Knowl-edge of conditions conducive for disease initi-ation and development was required for effectivescreening of plants in a breeding program andsubsequent selection of resistant genotypes.

In greenhouse tests using 10 ms/g soil, rootrot on peanut was most severe when plantswere grown in wet soil (field capacity) at 25°C(Phipps and Beute 1977). Soil temperatures of20° and 30°C resulted in moderate and low rootrot severities, respectively, in infested wet soil.At each temperature, a lesser degree of root rot

T73

resulted in infested, dry soil. Biopsied tissuesfrom plants indicated that more root infectionby C crotalariae occurred in infested, wet soil atall temperatures. In experiments usingnaturally-infested field soil (1.1 to 2.0 ms/g soil)disease severity was similar to that observed inartificially infested soil. Root rot was mostsevere in wet soil at 25°C. At each temperature,root rot was less severe in dry soil. It wasobserved in North Carolina that high rainfallearly in the growing season was necessary forsevere root rot since most peanut field soils arewell drained and sandy in texture. A subsequentperiod of moisture stress was thought to en-hance the expression of above groundsymptoms due to the absence or limitednumber of functional roots after infection androot rot.

The survival of C. crotalariae ms in soil did notappear to be affected by moisture or tempera-ture during the growing season (Phipps andBeute 1979). Incubation of soil samples in Vir-ginia at temperatures simulating winter condi-tions (6°C), however, decreased germinabilityof C. crotalariae ms (Roth et al. 1979). Incubationof naturally-infested soil under field conditionsfrom October to February (1978) indicated that a similar low-temperature-induced phenomenonexists in nature. When soil samples were trans-ferred to 26°C for 4 weeks, the low temperatureeffect was partially reversed.

Population Dynamics

Microsclerotia were considered to be primarysurvival propagules for C. crotalariae in fieldsoil. Development of semi-selective media withutilization of wet sieving and/or elutriationtechniques for extraction of ms from soil pro-vided the opportunity for enumeration of popu-lations of C. crotalariae in soil over time andcropping sequence. Fallow soil, nonhost ro-tational crops and CBR-resistant peanutgermplasm were compared with susceptiblepeanut cultivars for effect on ms populations infield plots.

Only slight reductions in ms densities weredetected in fallow soil and soil planted tononhost crops each year over two years testing(Phipps and Beute 1979). Incorporation of cropresidues (both host and nonhost) in soil afterharvest did not change ms densities after 5

months. After one growing season, populationsof ms at harvest were 9.6, 5.2, and 1.6 timespreplant densities in soils planted to the CBR-susceptible cultivar Florigiant, CBR-resistantArgentine and NC 3033, respectively. Mic-rosclerotia densities increased 3.7 times in soilplanted to soybean.

Disease severity in the field was shown toreflect sensitivity of susceptible and resistantpeanut cultivars to inoculum densities of C.crotalariae ms in soil (Phipps and Beute 1977).CBR-susceptible cultivars were severely dis-eased in soils having 0.5 ms/g soil or greaterinoculum densities if the environment wereconducive for infection. Resistant cultivars,however, grew and survived in soils having ashigh as 1000 ms/g soil. Resistant cultivars didsustain moderate to severe root rot and exten-sive root infection when inoculum densitieswere greater than 50 ms/g soil.

Nematode Interactions

Although a precise relationship had been de-scribed between inoculum density and diseaseseverity for both CBR susceptible and resistantpeanuts, response of peanut genotypes in in-fested fields was frequently different from thatpredicted on the basis of ms densities.Nematode populations were shown to be a major factor in modification of the diseaseincidence x inoculum density relationship.

Sequential inoculation with nematodes andC. crotalariae increased CBR severity on bothCBR-susceptible (Florigiant) and CBR-resistant(NC 3033) peanuts in greenhouse tests. The ED50

values (microsclerotia/cm3 soil to give 50%diseased plants) for Florigiant and NC 3033were decreased from 0.35 and 17.5, respec-tively, in fungus-only soil to 0.05 and 1.6, re-spectively, in soil containing Meloidogyne hap/a (Northern root knot nematode) and thefungus. Two populations of root knot nematodeM. arenaria (Race 2) which do not reproduce onpeanut, also enhanced CBR on NC 3033 ingreenhouse tests. Correlations between popu-lations of M. hapla and C. crotalariae with CBRseverity weresignificant in field tests conductedfrom 1976-1978. In greenhouse tests the EDeovalues for Florigiant were decreased from 0.42in fungus-alone soil to 0.05 in soil containingMacroposthonia ornata (ring nematode). M.

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ornata reproduced on NC 3033 in similar testsbut did not enhance CBR severity on NC 3033. Inmicroplot tests in the field where M. ornata wasused in combination with C. crotalariae on bothcultivars, more diseased plants occurred withM. ornata + C. crotalariae than with eitherpathogen alone on Florigiant but not on NC3033, although the nematode reproduction fac-tor was higher on NC 3033 than on Florigiant.

Fungal Genetics

Evaluation of peanut germplasm in field plotsover several years indicated that somegenotypes did not perform consistently at differ-ent locations (Wynne et al. 1975). Extremevariability in CBR severity under field conditionsand the prevalence of the sexual stage(perithecium) of C. crotalariae suggested thepossibility of physiological specialization in thefungus (Rowe and Beute 1975). All isolates ofthe fungus tested prior to 1974, regardless ofdiverse geographic origins, elicited the samegeneral pattern of host response on six peanutvarieties chosen to represent a range of CBRresistance. A wide range of virulence amongisolates did appear to be inherent in the fungus.This variability was not related to linear growthrate in culture nor was it correlated with geo-praphic distribution of the pathogen.

A subsequent test was initiated to re-evaluatethe variability in virulence of C. crotalariae isolates by using CBR resistant and susceptiblepeanut genotypes as host differentials to de-termine the effect of resistant host plant selec-tion on degree of differential interactions be-tween host and pathogen isolates (Hadley et al.1979). The mean virulence of isolates of C.crotalariae from susceptible peanut cultivarsdid notdifferfrom that of isolates from resistantpeanuts when selection pressure was appliedonly for one growing season. Differences werenoted, however, among isolates from resistantpeanuts when ranked for virulence. Isolatesfrom the resistant peanuts showed the highestlevel of virulence on resistant peanut, but wereno more virulent on the susceptible peanut thanisolates originating from susceptible peanuts.According to a pathogen virulence model, iso-lates originated from susceptible peanut hadabout eight times more general virulence thanspecific virulence. In only one cropping cycle of

CBR-resistant peanuts, specific virulence in-creased fourfold in the previously nonselectedpathogen populations. It was suggested that a potential exists for change in fitness in C.crotalariae, even though corresponding resis-tance in the host appears to be quantitativelyinherited.

A later experiment indicated that informationfor individual isolates may not be representa-tive of phenomenon in naturally occurringheterogenous fungus populations. Diseasereadings in the field for composites of isolates(chosen as specific for susceptible peanuts orspecific for resistant peanuts) suggested that aninteraction and/or recombination may be occur-ring among composited isolates of C.crotalariae during the growing season.

References

BELL, D. K. 1967. Effects of soil temperature and plantage on the severity of Cylindrocladium rot of peanut.Plant Disease Reporter 51: 986-988.

BELL, D. K., and SOBERS, E. K. 1966. A peg, pod, androot necrosis of peanuts caused by a species ofCalonectria. Phytopathology 56: 1361-1364.

BEUTE, M. K., and ROWE, R. C. 1973. Studies on thebiology and control of Cylindrocladium black rot(CBR) of peanut. Journal of American Peanut Re-search and Education Association 5: 197.

BYRD, D. W., Jr., BARKER, K. R., FERRIS, H., NUSBAUM,C. J, GRIFFIN, W. E., SMALL,R. H., and STONE, C. A 1976.Two semi-automatic elutriators for extractingnematodes and certain fungi from soil. Journal ofNeonatology 8: 206-212.

GARREN, K. H., BEUTE, M. K., and PORTER, E. M. 1972.The Cylindrocladium black rot of peanut in Virginiaand North Carolina. Journal of the American PeanutResearch and Education Association 4: 66-71.

GARREN, K. H., PORTER, D. M„ and ALLISON, A. H. 1971.Cylindrocladium black rot of peanuts in Virginia.Plant Disease Reporter 55: 419-421.

GRIFFIN, G. J. 1977. Improved selective medium forisolating Cylindrocladium crotalariae microsclerotlafrom naturally infested soils. Canadian Journal ofMicrobiology 23: 680-683.

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HADLEY, B. A., BEUTE, M. K., and LEONARD, K. J. 1979.

Variability of Cylindrocladium crotalariae responseto resistant host plant selection pressure in peanut.Phytopathology 69: 1112-1114.

JACKSON, C. R., and BELL, D. K. 1969. Diseases of

peanut (groundnut) caused by fungi. University ofGeorgia Agricultural Experiment Station ResearchBulletin 56. 137 pp.

JOHNSTON, S. A., and BEUTE, M. K. 1975. Histopathol-

ogy of Cylindrocladium black rot of peanut.Phytopathology 65: 649-653.

KRIQSVOLD, D. T., and GRIFFIN, G. J. 1975. Quantitative

isolation of Cylindrocladium crotalariae mic-rosclerotia from naturally-infested peanut and soy-bean field soils. Plant Disease Reporter 59: 543-546.

KRIGSVOLD, D. T., GARREN, K. H., and GRIFFIN, G. J.,

1977. Importance of peanut field cultivation andsoybean cropping in the spread of Cylindrocladium crotalariae within and among peanut fields. PlantDisease Reporter 61 : 495-499.

MISONOU, T. 1973. New black root rot disease in soy-beans and peanuts caused by Calonectrla crotalariae. Shokubutsu Boeki 27(2): 35-40.

PHIPPS, P. M., and BEUTE, M. K. 1977. Influence of soiltemperature and moisture on the severity of Cylin-drocladium black rot in peanut. Phytopathology67: 1104-1107.

PHIPPS, P. M., and BEUTE, M. K. 1977. Sensitivity of

susceptible and resistant peanut cultivars to in-oculum densities of Cylindrocladium crotalariae microsclerotia in soil. Plant Disease Reporter61: 300-303.

PHIPPS, P. M., and BEUTE, M. K. 1979. Population

dynamics of Cylindrocladium crotalariae mic-

rosclerotia in naturally-infested soil. Phytopathol-ogy 69: 240-243.

PHIPPS, P. M., BEUTE, M. K., and BARKER, K. R. 1976. An

elutriation method for quantitative isolation ofCylindrocladium crotalariae microsclerotia fromPeanut field soil. Phytopathology 66: 1255-1259.

ROTH, D. A., GRIFFIN, G. J., and GRAHAM, P. J. 1979. Low

temperature induces decreased germinability ofCylindrocladium microsclerotia. Canadian Journalof Microbiology 25: 157-162.

ROWE, R. C, and BEUTE, M. K. 1973. Susceptibility of

Peanut rotation crops (tobacco, cotton and corn) toCylindrocladium crotalariae. Plant Disease Reporter57: 1035-1039.

ROWE, R. C, and BEUTE, M. K. 1975. Variability in viru-lence of Cylindrocladium crotalariae isolates onPeanut. Phytopathology 65: 422-425.

ROWE, R. C, and BEUTE, M. K. 1975. Ascospore forma-t ion and discharge by Calonectria crotalariae. Phytopathology 65: 393-398.

ROWE, R. C, BEUTE, M. K., and WELLS, J. C. 1973.

Cylindrocladium black rot of peanuts in NorthCarolina, 1972. Plant Disease Reporter57: 387-389.

ROWE, R. C, BEUTE, M. K., WELLS, J. C, and WYNNE,

J. C. 1974. Incidence and control of Cylindrocladium black rot of peanuts in North Carolina during 1973.Plant Disease Reporter 58: 348-352.

ROWE, R. C, JOHNSTON, S. A., and BEUTE, M. K. 1974.

Formation and dispersal of Cylindrocladium crotalariae microsclerotia in infected peanut roots.Phytopathology 64: 1294-1297.

WYNNE, J. C, ROWE, R. C, and BEUTE, M. K. 1975.

Resistance of peanut genotypes to Cylindrocladium crotalariae. Peanut Science 2: 54-56.

176

Sclerotinia Blight of Groundnut — A Diseaseof Major Importance in the USA

D. Morris Porter*

A disease of the groundnut {Arachis hypogaea L.) caused by a Sclerotinia sp was reported firstin Argentina in 1922 (Marchionatto 1922). In1933, Sclerotinia spp were reported attackinggroundnuts in China (Chu 1933) and in 1948 S.minor Jagger was the causal agent of a seriousgroundnut disease in Australia (Anon. 1948). A root and pod rot disease of groundnuts causedby S. minor and S. sclerotiorum (Lib.) de Barywas reported again in Argentina in 1960 (Frezzi1960). A wilt of peanut caused by S. miyabeana Hanzawa was reported in Taiwan in 1972 (Janand Wu 1972). Sclerotinia was observed first onpeanuts in the United States in 1971 (Porter andBeute 1974) and has since become widespreadin Virginia, North Carolina and Oklahoma. Infact, it is nowthe most serious disease problemin Virginia (Powell etal. 1976; Porter etal. 1977).Sclerotinia blight has not been observed inGeorgia, Florida, Texas or Alabama wheregroundnuts are grown commercially.

Symptoms

The first symptom of Sclerotinia blight is usu-ally the sudden wilting of a lateral branch of a groundnut plant (Porter and Beute 1974). Infec-tion of the main branch usually occurs by

* Plant Pathologist, AR, SEA, U.S. Department ofAgriculture, Suffolk, Virginia 23437, USA.Cooperative investigations of Agricultural Re-search, Science and Education Administration,U.S. Department of Agriculture, and Research Divi-sion, Virginia Polytechnic Institute and State Uni-versity, (VPI & SU). Contribution No. 414, Depart-ment of Plant Pathology and Plant Physiology, VPI& SU, Blacksburg, USA.This paper reports the results of research only.Mention of a pesticide in this paper does notconstitute a recommendation by the USDA nordoes it imply registration under FIFRA.

growth of the fungus into the main branch froman infected lateral branch. The foliage on in-fected branches becomes chlorotic, turns darkbrown and withers, followed by death anddefoliation of that branch. These symptomsresult in a blight of the foliage characteristic ofSclerotinia disease (Fig.1-A). Once infection hasbeen initiated and environmental conditionsconducive to disease development persist,white, fluffy mycelium (Fig. 1-B) will develop onthe diseased tissue.

The infection process appears to be bothintra- and inter-cellular with enzymatic activityconcentrating in the middle lamella, resulting intissue shredding. Shredding of the branch tis-sue is a characteristic sign of Sclerotinia blight(Fig. 1-C). Shredding of the peg tissue alsooccurs and results in severe pod shed (Fig. 1-D).Branch lesions are initially light tan and elon-gated along the axis of the branch (Fig. 2-D). Aslesions develop and age, they become dry anddark brown with a distinct demarcation zoneseparating infected and healthy tissue. Black,irregularly shaped sclerotia (0.02-3.0 mm) areproduced abundantly on the outside of allinfected groundnut plant parts including thebranches (Figs. 2-B, 2-D), pegs, and shells, andon the inside of branches, tap roots and underthe epidermal layers of the pods (Fig. 2-B) and inthe pod, both on the pod interface and on theseed (Porter and Beute 1974).

Causal Organism

Speciation of Sclerotinia usually is based in parton host range and size of sclerotia. Sclerotinia spp including both small and large sclerotium-producing isolates, attack a wide host range ofcrops (Abawi and Grogan 1979). The impracti-cality of separating Sclerotinia species based onsclerotia! size was demonstrated by Purdy(1955) who showed thatthe small sclerotial type

177

(S. minor), the intermediate sclerotial type (S.trifoliorum Eriks.) and the large sclerotial type(S. sclerotiorum) often produced sclerotia ofintermingling sizes among groups. Purdy,therefore, synonymized several species of S.sclerotiorum.

In Virginia, the species of Sclerotinia pathogenic to groundnuts produced smallsclerotia ranging in size from 0.02-3.0 mmwhich were similar to those described by Jag-ger (1920). Both small and large sclerotium-producing isolates of Sclerotinia were found ingroundnut fields where Sclerotinia was preva-lent in Oklahoma (Wadsworth 1979). Apotheciaof S. minor and S. sclerotiorum have beenobserved in Oklahoma but not in Virginia andNorth Carolina. To resolve the taxonomic posi-tion of the genus Sclerotinia, Kohn (1979) usedseveral taxonomic characters including the de-velopment of a free, discreet sclerotium, ab-sence of functional conidia, production of as-cospores and orientation of the cells in theoutermost layer of the apothecium to delineatethree species of Sclerotinia :-S. sclerotiorum, S.minor and S. trifoliorum. Using a neotypespecimen obtained from a diseased groundnutshowing symptoms of Sclerotinia blight in a field in Virginia in 1974, Kohn identified thecausal organism as S. minor.

Disease Cycleand Epidemiology

Infection of groundnuts by S. minor is my-celiogenic, that is, it originates from mycelia ofgerminating soil-borne sclerotia (Beute et al.1975; Wadsworth 1979). Sclerotinia minor usu-ally invades groundnut tissue includingbranches, leaflets and pegs at points of soilcontact. In Oklahoma, Wadsworth (1979) founda few infection sites some distance from soilcontact points and suggested the possibility ofascospore involvement in disease develop-ment.

Under moist conditions defoliated groundnutleaflets or senescing leaflets still attached to theplant, but in contact with the soil, are easilycolonized by mycelia from germinatingsclerotia of S. minor. This food base enhancesdisease development but is not a necessaryprerequisite for infection since infection sitescommonly appear on branches in contact with

the soil but without the presence of such foodbases. For some diseases caused by Sclerotinia spp a source of nutrition is a prerequisite forpenetration and infection of host tissue (Purdy1958). Volatile stimulants from remoistenedleaves greatly influenced the germination ofsclerotia of 5. minor over a wide pH range, withoptimum germination occurring at pH 6.5 (Hauet al. 1980).

The incidence and severity of Sclerotinia blight can be detected by aerial infrared photo-graphy (Fig. 1-E). Sclerotinia blight ofgroundnut, characterized by a unique spectralsignature, can be detected on infrared imagerytaken at altitudes of about 20 000 meters, butlower altitudes (3500 meters) provided betterresolution for detailed study (Powell et al. 1976).The severity of Sclerotinia blight as detected ininfrared imagery can be correlated with actualpod losses in the field (Porter et al. 1977). Areason infrared photographs that were interpretedas slightly, moderately or severely damaged byS. minor, had groundnut pod losses due to thedisease which were 2, 5, and 7 times greater,respectively, than nondiseased areas. Inseverely damaged fields, groundnut losses dueto S. minor often exceed 50% of expected yield.

Infection by most Sclerotinia species is gen-erally dependent upon low temperatures (10-25°C) and high soil moisture (Abawi and Grogan1979). The severity of Sclerotinia blight ofgroundnuts in Virginia can be correlated withtemperature (D. M. Porter, unpublished data).The number of days the mean temperaturedropped to 21°C and below during July, Augustand September in Virginia was 23,13,26,12,18and 21, respectively, in 1974 through 1979.Sclerotinia blight was more severe in yearshaving the greater number of cool days. It wasmost severe in 1974 and 1976 and almost nil in1975. The disease was much widely spread in1976 than in 1974. Disease losses were minimalin 1977, but were severe in 1978 and 1979.Patterns of disease severity during each yearwere verified with infrared photography (Cobbet al. 1977).

Mechanically injured groundnut foliage isvery susceptible to colonization by S. minor (Porter and Powell 1978). Groundnut plants,injured by tractor tires during pesticide applica-tion, were colonized by S. minor at twice thefrequency of noninjured plants. At one locationwhere Sclerotinia blight was severe, 152% in-

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Figure /. A, groundnut field exhibiting typical symptoms of Sclerot in ia blight; B. character-istic white, fluffy mycelium growing on infected groundnuts; C. typical shredding of plant tissue following colonization by S. minor; D, groundnut pods remaining insoil following harvest of plants severely infected with S. minor; and E, infrared photograph showing distribution of symptoms of S. minor in a groundnut field (red color = healthy plants and gray color represents diseased areas).

crease in disease was noted in plants injured bytractor tires. Pod yield losses can also be corre-lated with plant injury. At two locations whereSclerotinia was severe, yields averaged 1736kg/ha in injured rows and 2658 kg/ha in non-injured rows. Aerial infrared photographs read-ily show Sclerotinia blight in row middlesinjured by tractor tires (Fig. 2-A).

From studies on the ecology and the survivalof sclerotia of S. minor it was found thatsclerotia are produced abundantly on infectedgroundnuts. Sclerotial populations, recoveredby sieving (Fig. 2-E), were 10 times greater insoil from severely infected areas of the fieldthan from slightly infected areas (Porter et al.1977). Sclerotia of S. minor can be observed ongroundnut debris 6 months following harvest(Fig. 2-B). At time of seeding, sclerotial countsmade from the top 2.5 cm of soil may be lessthan one sclerotia per 100 g soil (D. M. Porter,unpublished data). Immediately after harvestand following a severe infection by S. minor, sclerotial counts may exceed 50 sclerotia per100 g soil from the top 2.5 cm soil layer.

Sclerotia can be recovered from thetop 20 cmof soil from fields having histories of Sclerotinia blight. Sclerotia of S. minor can survive in thesoil for several years. In a field having a historyof Sclerotinia blight, but planted to a nonhostcropforthreegrowing seasons, sclerotial popu-lations declined only slightly and sclerotia ger-minated readily.

Many genera of fungi can be isolated fromsclerotia of S. minor. However, the mycoflora ofsurface-sterilized sclerotia is usually dominatedby species of Trichoderma which can be readilyobserved on the sclerotia in groundnut pods leftin the field following harvest.

Sclerotinia minor can be transmitted by seed,but at a low frequency (D. M. Porter, unpub-lished data). Pods obtained from groundnutplants exhibit ing severe symptoms ofSclerotinia blight were shelled, disinfected forthree minutes and plated on several media.After incubation for 14 days, S. minor grew fromless than 1% of the seed.

Soybean {Glycine max L Merr.) plants aresusceptible to Sclerotinia spp. Both S. minor and S. sclerotiorum were isolated from dis-eased soybean plants growing in close proximi-ty to groundnut fields (Phipps and Porter 1977).In greenhouse inoculation tests, both specieswere pathogenic to groundnuts. However, S.

sclerotiorum has not been observed in Virginiabut has been observed in Oklahoma(Wadsworth 1979).

Control

Differences in susceptibility of 36 groundnutcultivars, breeding lines and plant introductionsto S. minor ranged from slight to severe (Porteret al. 1975). Florigiant, a cultivar currentlyplanted on over 90% of the groundnut acreagein Virginia and North Carolina, was the mosttolerant to S. minor of any cultivar tested. A North Carolina breeding line, 17165, and PI343392 were more tolerant than any of the otherlines tested. In a 3-year study under severedisease pressure in Virginia, PI 371521 and a breeding line, Virginia 71—347, were not im-mune to S. minor but exhibited significantlyfewer symptoms of this disease than othercultivars, breeding lines and plant introductionsscreened (Coffelt and Porter 1980).

Botran (2, 6-dichloro-4-nitroaniline) providedpartial control of Sclerotinia blight ingroundnuts in Virginia and North Carolina(Beute et al. 1975). Benomyl (methyl1-[butylcarbamoyl]-2-benzimidazolecarbamate),applied at high rates (4.48 and 6.62 kga.i./ha) provided some control of Sclerotinia blight (Porter 1977). Procymidone (3-[3,5-dichlorophenyl ] -1, 5-dimethyl-3-azabi-cyclo[3.1.0]hexane-2, 4-dione), a Dupontexperimental fungicide (DPX 4424) not regis-tered for use on groundnuts and recently with-drawn from testing by the company, providedalmost complete control of Sclerotinia blight(Porter 1980b). Pod yields in plots treated withprocymidone (0.56 kg a.i./ha x four applica-tions applied directly to the groundnut foliageas a broadcast spray) averaged 4904 kg/hacompared to 2603 kg/ha in the untreated plots(Fig. 2-C). Fungicides closely related to pro-cymidone such as Ridomil (methyl D, L-N-[2,6-dimethylphenyl]-N-[2-methoxyacetyl]-alanin-ate) and Rovral (1-isopropyl-carbamoyl-3[3-5dichlorophenyl] hydantoin) were not effectiveagainst Sclerotinia blight (Phipps 1980). The useof metham (sodium N-methyldithiocarbamate)applied in irrigation water for control ofSclerotinia blight was recently demonstrated(Krikun et al. 1980).

Sclerotinia blight of groundnuts can be sup-

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pressed with dinitrophenol herbicides (Porterand Rud 1980). Oinoseb (2-sec-butyl-4,6-dinitrophenol) and naptalam (sodium N-1-naphthylphthalamate) + dinoseb applied broad-cast at 0.84 kg/ha significantly reduced theseverity of Sclerotinia blight and increasedgroundnut yields. Crop value was increased byabout 18% in herbicide-treated plots.

Plant nutrients such as zinc and coppersulfates applied to the groundnut foliage sig-nificantly suppressed the development ofSclerotinia blight (Hallock and Porter 1979).These same nutrients applied to the soil had noeffect on disease suppression. Several otherplant nutrients, including N, K, Ca, Mg, P, Mn,Fe, B, S and CI, had little or no effect on disease.

Some fungicides currently recommended asstandard production practices to controlleaf spot (Cercospora arachidicola Hori and Cer-cosporidium personatum [Berk, and Curt.]Deighton) of groundnut enhance the severity ofSclerotinia blight. In fungicide screening testsconducted in Virginia in 1974, the severity ofSclerotinia blight was significantly greater inplots treated wi th chlorothaloni l (tet-rachloroisophthalonitrile) than in nontreatedplots (Beute et al. 1975). In later studies,chlorothalonil applied at rates recommendedfor leaf spot control not only increased theseverity of Sclerotinia blight but also signifi-cantly reduced pod yield (Porter 1977). At otherfield locations, captafol (cis-N-[{1,1,2,2,-tetrachloroethyl} thio] 4-cyclohexene-1,2-dicarboximide), as well as chlorothalonil,enhanced the severity of Sclerotinia blightand significantly decreased pod yield (Porter1980a).

At harvest, two and four times more plantsweredead in plots treated with chlorothalonil orcaptafol, respectively, than in untreated controlplots. Pod yields averaged about 500 kg/hagreater in untreated plots than in chlorothalonil,or captafol treated plots. Sclerotinia blight wassignificantly greater in all breeding lines, plantintroductions and cultivars treated withchlorothalonil than plants treated with benomyl(Coffelt and Porter 1980). Both fungicides wereused at rates recommended for leaf spotcontrol. The reason(s) for enhancementof Sclerotinia blight following usage ofchlorothalonil and captafol is not known. Thesoil microflora from plots treated withchlorothalonil and captafol was not different

from that obtained from nontreated plots(Lankow et al. 1980). In greenhouse-grownplants, inoculation with chlorothalonil-treatedinoculum enhanced the virulence of S. minor (M. K. Beute, personal communication). Oxalicacid production was over 2.5 times greater inmedium amended with chlorothalonil and cap-tafol than in similar nonamended media. Theincreased production of oxalic acid by S. minor following application of either chlorothalonil orcaptafol may partially explain the enhancementof Sclerotinia blight under field conditionswhere these fungicides are utilized.

References

ABAWI.G. S., and GROGAN.R.G. 1979. Epidemiology ofdiseases caused by Sclerotinia. Phytopathology69: 899-904.

ANONYMOUS. 1948. Plant diseases. Notes contributedby the biological branch. Agricultural Gazette ofNew South Wales 59: 527-530.

BEUTE, M. K., PORTER, D. M., and HADLEY, B. A. 1975.Sclerotinia blight of peanut in North Carolina andVirginia and its chemical control. Plant DiseaseReporter 59(9): 697-701.

CHU, V. M. 1933. Notes on the presence of Sclerotinia miyabeana in China, with special reference to thecomparison of this fungus with Sclerotinia arachidis. 1932 Yearbook of the Bureau of Entomol-ogy, Hankow, China. (Review of Applied Mycology13: 615-616. 1934).

COBB, P. R., POWELL, N. L, and PORTER, D. M. 1977.Survey of Sclerotinia sclerotiorum blight diseaselosses in peanut fields by remote sensing. Proceed-ings of the American Peanut Research and Educa-tion Association 9(1): 94.

COFFELT, T. A., and PORTER, D. M. 1980. Screeningpeanuts iArachis hypogaea L.) for resistance toSclerotinia blight. Proceedings of the AmericanPeanut Research and Education Society 12.

FREZZI, M. J. 1960. Enfermedades del mani el laprovincia de Cordoba (Argentina). Revista de Inves-tigaciones Agricolas 14: 113-155.

HALLOCK, D. L, and PORTER, D. M. 1979. Nutrienteffects on Sclerotinia blight disease in peanuts.Proceedings of the American Peanut Research andEducation Society 11: 62.

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Figure 2. A. infrared photograph showing relationship of mechanical injury and subsequent colonization of injured groundnut foliage by S. minor (note alternating bands ofred and gray representing healthy and diseased tissue, respectively); B. over-wintering of sclerotia of S. minor on groundnut debris; C. control of Sc lerot in iablight of groundnut with experimental fungicide; D, typical stem lesions on ground-nuts caused by S. minor; and E. sclerotia of S. minor on sieve.

HAU, F. C, BEUTE, M. K., and PORTER, D. M. 1980. Effect

of soil pH and the presence of remoistened peanutleaves in germination oiSclerotinia minor sclerotia.Proceedings of the American Peanut Research andEducational Society 12: 32.

JAGGER, I. C. 1920. Sclerotinia minor, n. sp, the causeof a decay of lettuce, celery, and other crops. Journalof Agricultural Research 20: 331-334.

JAN, C. J., and Wu, L. C. 1972. Studies on peanut wilt inTaiwan. Memoirs of the College of Agriculture,National Taiwan University 13: 1-23.

KOHN, L. M. 1979. A monographic revision of thegenus Sclerotinia. Mycotaxon 9: 365-444.

KRIKUN, J., PAPAVIZAS, G. C, and FRANK, Z. 1980.

Application of metham through sprinkler irrigationfor control of soilborne pathogens of peanuts. Pro-ceedings of the American Peanut Research andEducation Society 12: 42.

LANKOW, R. K., PORTER, D. M, and GOUERT, J. R. 1980.

The effect of fungicides on peanut field soil mic-roflora. Proceedings of the American Peanut Re-search and Education Society 12: 33.

MARCHIONATTO, J. B. 1922. Peanut wilt in Argentina.Revista de la Facultad de Agronomia, UniversidadNacional de La Plata 3: 65-67.

PHIPPS, P. M. 1980. Control of Sclerotinia blight inVirginia, Isle of Wight. Fungicide and nematicidetests 35: 212.

PHIPPS, P. M., and PORTER, D. M. 1977. Sclerotinia

blight of soybean in Virginia. Phytopathology69: 1042. (Abstr.)

PORTER, D. M. 1977. The effect of chlorothalonil andbenomyl on the severity of Sclerotinia sclerotiorum blight of peanuts. Plant Disease Reporter61(12): 995-998.

PORTER, D. M. 1980a. Increased severity of Sclerotinia blight in peanuts treated with captafol andchlorothalonil. Plant Disease 64: 394-395.

PORTER, D. M. 1980b. Control of Sclerotinia blight ofpeanut with procymidone. Plant Disease 64.

PORTER, D. M., and BEUTE, M. K. 1974. Sclerotinia

blight of peanuts. Phytopathology 64(2): 263-264.

PORTER, D. M., BEUTE, M. K., and WYNNE, J. C. 1975.

Resistance of peanut germplasm to Sclerotinia sclerotiorum. Peanut Science 2(2): 78-80.

PORTER, D. M., POWELL, N. L, and COBB, P. R. 1977.

Severity of Sclerotinia minor blight of peanuts asdetected by infrared aerial photography. PeanutScience 4(2): 75-77.

PORTER, D. M., and POWELL, N. L. 1978. Sclerotinia

blight development of peanut vines injured bytractor tires. Peanut Science 5(2): 87-90.

PORTER, D. M., and RUD, O. E. Suppression ofSclerotinia blight of peanuts with dinitrophenolherbicides. Phytopathology 70: (In press).

POWELL, N. L, PORTER, D. M., and PETTRY, D. E. 1976.

Use of aerial photography to detect diseases inpeanut fields. I. Sclerotinia blight. Peanut Science3(2): 21-24.

PUROY, L. H. 1955. A broader concept of the speciesSclerotinia sclerotiorum based on variability.Phytopathology 45: 421-247.

PURDY, L. H. 1958. Some factors affecting penetrationand infection by Sclerotinia sclerotiorum. Phytopathology 48: 605-609.

WADSWORTH, D. F. 1979. Sclerotinia blight of peanutsin Oklahoma and occurrence of the sexual stage ofthe pathogen. Peanut Science 6: 77-79.

185

Groundnut Foliar Disease in the United States

D. H. Smith*

Fungal Diseases

Although several groundnut foliar diseaseshave been reported in the United States, earlyand late leaf spot are the most widely distributedfoliardiseasesofgroundnuts. Theearly and lateleaf spot pathogens are seen primarily in theirimperfect states, i.e., as Cercospora arachidicola Hori, and Cercosporidium per-sonatum (Berk. & Curt.) Deighton. The perfectstates of both pathogens have been reported inthe United States, but there is no convincingevidence that ascospores are an importantsource of initial inoculum.

Since 1976, there has been a gradual shiftfrom a predominantly early leaf spot populationto a substantial amount of late leaf spot in thesoutheastern United States (Smith and Littrell1980). A totally satisfactory explanation for thischange is not available, but some plausible ex-planations are worthy of consideration.

First, the groundnut crop has been harvestedlater in recent years, and this may have con-tributed to an increased inoculum potential of C.personatum. Second, the use of highly effectivefungicides for early leaf spot may have alteredthe leaf surface microflora, thereby providing a competitive advantage for the late leaf spotfungus. Third, the extensive cultivation of onesusceptible cultivar (Florunner) in Alabama,Florida, and Georgia may have favored a shiftfrom early to late leaf spot. Other possible con-tributing factors include nutrient status of thecrop, drought stress, previous crop sequence,increased use of irrigation in groundnut produc-tion, and unsatisfactory fungicide applicationschedules and methods of application.

The shift in the relative abundance of earlyand late leaf spot is not a new phenomenon.During a 5-year period in the late 1920's and

* Associate Professor, Texas A&M University, TexasAgricultural Experiment Station, Plant Disease Re-search Station, Yoakum, Texas 77995, USA.

early 1930's in Georgia, Woodruff (1933) re-ported that early leaf spot contributed to severedefoliation during only two of five years. A fewyears later, again in Georgia, Jenkins (1938)reported that early leaf spot reached epidemicproportions in August and early September,whereas late leaf spot was most destructivefrom September through harvest. Late leaf spotwas of minor importance in Georgia from1967-1976 (Smith and Littrell 1980). In 1947,Miller (1953) collected groundnut leaves fromten southern states, and he reported that82% of the lesions were caused by C. ara-chidicola. During the 1979 growing season,the incidence of early and late leaf spot wasmonitored in a small-plot field test in Georgia.Late leaf spot was not observed until the secondweek in July, but by the end of the season morethan 99% of the lesions were those of C. per-sonatum (Smith and Littrell 1980).

Groundnut rust, caused by Puccinia arachidis Spegazzini, occurs annually in the groundnutproducing areas of southern Texas. Groundnutrust has been observed in all the groundnutproducing states, but the onset of rust is usuallylate in the season. Therefore, with the exceptionof southern Texas, rust does not usually con-tribute to groundnut crop losses.

Only the uredial state of P. arachidis has beenobserved in United States, and the fungus doesnot survive during the intercrop period. Air-borne uredospores are introduced annuallyfrom outside of the United States (Van Arsdel1972). Harrison (1972) observed groundnut rustin southern Texas during the first week of Julyin 1971. This is probably the earliest thatgroundnut rust has ever been observed in theUnited States. During 1971, rust reachedepidemic proportions in southern Texas (Harri-son 1972). During the same growing season,Thompson and Smith (1972) reported rust in 24groundnut producing counties in Georgia.

Web blotch, caused by Phoma arachidicola, Marasas, Pauer & Boerema was first reportedin Texas during the 1972 growing season (Pettit

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et al. 1973). However, the fungus was pre-sent in groundnut hay which was pro-duced in Florida during the 1971 crop year(Smith, unpublished). Since then, web blotchhas been observed in several states, butepidemics of web blotch have been limited toTexas and Oklahoma. During recent years theincidence of web blotch has been diminishing inthe United States. We believe this is at leastpartially associated with the decreasing amountof highly susceptible Spanish type cultivars andan increasing amount of Florunner, a cultivarwith moderate resistance to web blotch (Smithet al. 1979). Both the perfect and the imperfectstates of the web blotch fungus have beenreported in the United States (Philley 1975).

Leptosphaerulina crassiasca (Sechet)Jackson & Bell is a ubiquitous fungus in thegroundnut producing areas of the UnitedStates, but it is usually a minor foliar pathogen.In contrast with the early and late leaf spot fungi,only the perfect state of L crassiasca is knownto plant pathologists. L. crassiasca producestwo distinct symptoms, i.e., pepper spots andwedge-shaped leaf scorch symptoms. Fre-quently, leaf scorch symptoms are accom-panied by early or late leafspot lesions at or nearthe midvein in the scorched portion of the leaf,indicating that L crassiasca may be only a secondary invader of the leaflet. Smith andCrosby (1973) studied the aerobiology of Lep-tosphaerulina crassiasca. They reported thatlarge numbers of L crassiasca ascospores weretrapped within 1-4 hours after sunrise, when airtemperature was rising and foliage was dryingon days without rain. On days with rain, con-centrations of L. crassiasca ascospores in-creased rapidly with the onset of rainfall.Mercer (1977) reported L trifolii as a foliarpathogen of groundnuts in Malawi, but we areunaware of any reports of L trifolii as a groundnut foliar pathogen in the United States.

Phyllosticta leaf spot, a minor foliar disease ofgroundnuts, has been reported in Georgia(Jackson and Bell 1969), and we have observeda low incidence of this leafspot disease in Texaseach year. Jackson and Bell observed the dis-ease early in the growing season, but we haveobserved it throughout most of the growingseason. We have frequently been able to findPhyllosticta sp in groundnut fields infested withjohnsongrass. On the basis of similarsymptoms on johnsongrass, we think that this

grass may be a host for the Phyllosticta sp thatinvades groundnut foliage. However, cross in-oculation studies have not been conducted.

Several other minor fungal pathogens ofgroundnut foliage have been reported in theUnited States. Smith (1972) reported that Cris-tulariella pyramidalis caused a leaf spot diseaseof groundnuts in Georgia. Littrell (1974a) re-ported that a foliar blight of groundnuts inGeorgia was caused by Rhizoctonia solani. Jackson and Bell (1969) found that a species ofColletotrichum, closely related to C. dematium, was consistently associated with leaf scorchsymptoms, but their attempts to produce leafscorch symptoms with this Colletotrichum spwere not successful. Jackson and Bell (1969)reported that Phomopsis sp was usually as-sociated with L crassiasca, Cercospora spp orColletotrichum cf dematium in marginal necro-tic leaflet lesions. We have isolated Alternaria spp from leaf scorch lesions, but inoculationshave been unsuccessful (Smith, unpublished).

Virus Diseases

Groundnut mottle is the most widely distributedgroundnut virus in the United States.Kuhn (1965) published the first report ongroundnut mottle in the United States. Demskiet al. (1975) reported that groundnut mottlevirus occurred in all the major groundnut pro-ducing states, i.e., Georgia, Florida, Alabama,Texas, Oklahoma, New Mexico, North Carolina,and Virginia.

In Georgia the incidence of peanut mottlevirus varied from 1 to 79% (Paguio andKuhn 1974). Paguio and Kuhn conducted a groundnut mottle virus survey in 1973, and theyreported a crop loss greater than 12 dollarsper acre in 46% of the fields surveyed;moreover, the estimate of the Georgiagroundnut crop loss attributed to ground-nut mottle virus was more than 11 milliondollars in 1973. Demski et al. (1975) reported a low incidence of groundnut mottle virus inTexas and Oklahoma, and they suggested thatthe appropriate aphid vectors may be absent inthese groundnut producing areas.

Miller and Troutman (1966) observedgroundnut stunt in Virginia in 1964, and Cooper(1966) observed the disease during the sameyear. Epidemics of groundnut stunt developed

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in North Carolina and Virginia in 1965 and 1966(Cooper 1966; Hebert 1967; Miller and Trout-man 1966). Since then, groundnut stunt hasbeen a minor disease of groundnuts in theUnited States. Groundnut stunt has also beenreported in Alabama and Georgia (Rogers andMixon 1972; Kuhn 1971). In 1967, Choopanya(1968) found groundnut stunt virus in whiteclover throughout most of South Carolina.However, Choopanya did not find the disease inSouth Carolina groundnut fields.

Spotted wilt of groundnuts was reported inTexas by Halliwell and Philley (1974). Since theirreport, this author has observed a few infectedplants in Texas each year, but there has been notendency for the disease to increase in Texas,and spotted wilt has not been reported in othergroundnut producing states.

Physiological Disorders

Various types of foliar symptoms are occasion-ally observed on groundnuts in the UnitedStates. In Texas and Oklahoma a symptomdescribed as atmospheric scorch (Home 1974)is probably caused either totally or partially byozone. The first evidence of ozone injury is a slight burn on the adaxial leaf surface, and thisprogresses to a dark brown scorched area. Cellsof the upper epidermis are usually most af-fected, but injury sometimes proceeds rapidlywhen secondary organisms invade the dam-aged tissue. Spanish market type peanuts aregenerally more susceptible than runner markettypes. Davis and Smith (1976) compared thereaction of ten groundnut cultivars to ozoneunder controlled conditions. Severity ratingsranged from O to 83.5, with Valencia A being mostsusceptible to ozone damage in contrast with a severity rating of 0.5 for Florunner.

Variegated leaves resulting from a geneticabnormality are occasionally observed. Thereseems to be a slightly higher incidence of this inSpanish market types, but we have also ob-served this variegated symptom on Florunner.

Various kinds of foliar symptoms induced bypesticides have been observed. Sometimesthese symptoms closely resemble Cercospora leaf spot. In questionable instances we incubateleaves on moist filter paper to induce sporula-tion. The absence of sporulation providescircumstantial evidence that the symptom

is associated with phytotoxicity instead ofCercospora leaf spot.

Managementof Fungal Diseasesof Groundnut Foliage

Several crop management practices reduce theamount of inititial inoculum. Burial of cropresidue with a moldboard plow is especiallyimportant when crop rotation is not part of thecrop management system. Crop rotation iseffective for reducing the inoculum potential ofboth soil-borne fungal and nematode patho-gens. In addition, when groundnuts are plantedon land that has not been planted to peanuts forone or more years, the onset and rate of diseaseprogress for early and late leaf spot are delayedas contrasted with disease progress in a pro-gram of continuous groundnut culture.

In the groundnut producing area of southernTexas, growers can avoid the impact ofgroundnut rust epidemics by plantinggroundnuts in early March. Since rust has neverbeen observed prior to the first week in July insouthern Texas, a crop planted in early March isusually exposed to rust for less than a monthprior to harvest. Therefore, crop losses attribut-able to rust are avoided by early planting. Inaddition, fewer fungicide applications are re-quired for management of early and lateleaf spot when groundnuts are planted in earlyMarch.

In southern Texas the groundnut plantingseason ranges from early March to mid-July.Because inoculum concentration increases asthe season progresses, foliar diseases are par-tially managed by planting successively latergroundnut crops in fields that are not adjacentto previously planted groundnut fields and notlocated in the direction of prevailing winds. Thedirection of prevailing wind is extremely rele-vant to the development of rust epidemics,because uredospores are well adapted to longdistance dispersal.

Fungic ides

Management of foliar diseases with fungicidesis a routine crop management practice in theUnited States. Prior to 1971, dust formulationsof copper, sulfur, and copper plus sulfur were

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routinely used for suppression of foliar dis-eases. However, after the introduction of be-nomyl, chlorothalonil, and fentin hydroxidethere was a rapid transition from dusting tospraying.

Chlorothalonil is the most widely used fun-gicide for management of groundnut foliardiseases in the United States. It is effectiveagainst early leaf spot, late leaf spot, rust, andweb blotch. Benomyl, captafol, copper am-monium carbonate, copper hydroxide, fentinhydroxide, mancozeb, maneb, and sulfur arecurrently registered for use in managing one ormore foliar diseases of groundnuts in theUnited States.

Thefirstfungicideapplication is usually madewithin 30-40 days after planting, with sub-sequent applications at intervals of 10-14 daysuntil 14-21 days prior to the anticipated date ofharvest. Fungicides are currently applied withvarious kinds of tractor propelled sprayers,fixed-wing aircraft, and sprinkler irrigation sys-tems.

Fungic ide To lerance

Benomyl-tolerant strains of C. arachidicola andC. personatum developed in the southeasternUnited States after three years of extensive useof benomyl for control of groundnut foliardiseases (Clark et al. 1974; Littrell 1974b).Groundnut crop losses were probably avertedby changing to the use of protectant fungicidesin 1974.

Smith et al. (1978) reported benomyl-tolerantstrains of C. arachidicola and C. personatum atone research station in Texas. They attributedthe development of tolerant strains to the an-nual evaluation of benomyl-alone foliar spraysin small plot field tests since 1967 and thesubsequent selection pressure for the de-velopment of benomyl-tolerant strains of C.arachidicola and C. personatum. There are noreports of the benomyl-tolerant strains of C.arachidicola and C. personatum strains in Texasgrower fields. A plausible explanation for thisfact is that Texas growers have not extensivelyused benomyl alone because of its ineffective-ness against rust and web blotch.

Smith and Searcy (1975) tested 57 isolates ofC. arachidicola from 11 states and 5 foreigncountries for benomyl tolerance. All isolateswere collected prior to the use of benomyl, and

no tolerant strains were found. In addition, wehave monitored a groundnut field where nofungicides are used and no benomyl-tolerantstrains of C. arachidicola have been isolated(Smith, unpublished). On the basis of the previ-ous circumstantial evidence, it appears that theincidence of benomyl-tolerant strains of C.arachidicola is probably very low or absentprior to the intensive use of benomyl.

Some effects of fungicides on nontarget or-ganisms have been reported. Backman et al.(1975) observed a consistently higher level ofSclerotium rolfsii Sacc. when Florunner foliagewas sprayed with benomyl. Porter (1980) re-ported that foliar sprays of captafol andchlorothalonil increased the severity ofSclerotinia blight on VA 72 R groundnuts.Campbell (1978) reported that foliar sprays ofeither fentin hydroxide or copper ammoniumcarbonate suppressed populations of the two-spotted spider mite. Backman et al. (1977)reported that Guazatine Triacetate, a fungicidewith efficacy against Cercospora leaf spot, repel-led lepidopterous larvae.

Research on resistance to early and lateleaf spot has been accelerated in recent years(Abdou et al. 1974; Sowell et al. 1976; Hassanand Beute, 1977; Sharief et al. 1978; Kornegayet al. 1980). Sources of rust resistance havebeen reported (Bromfield and Cevario 1970;Hammons 1977; Subrahmanyam et al. 1980).Smith et al. (1979) reported some sources ofweb blotch resistance. Porter et al. (1971)evaluated breeding lines and cultivarsfor resis-tance to pepper spot and leaf scorch under fieldconditions. However, in spite of the increasedemphasis on resistance to fungal diseases ofpeanut foliage, there are currently no agronomi-cally acceptable cultivars with adequate resis-tance to eliminate the use of fungicides formanagement of the principal foliar diseases ofgroundnuts.

Management of Virus Diseasesof Groundnuts in the UnitedStates

There is no satisfactory control measure forgroundnut mottle virus. Since the symptomsare frequently inconspicuous, growers areoften unaware of this disease in their fields.Kuhn et al. (1968) found no immunity to PMV

189

when they screened 37 peanut cultivars and 428plant introductions in the greenhouse. Screen-ing was done by mechanical inoculatinggroundnut plants and then subinoculatingPhaseolus vulgaris Topcrop' a local lesion host.In a 1978 report, Kuhn et al. indicated that PI261945 and PI 261946 were tolerant, becauseinfection did not reduce pod yield.

The production of groundnut mottle virus-free seed is a potential control measure. Demskiet al. (1975) reported a low incidence ofgroundnut mottle in Texas and Oklahoma, andthey suggested that these may be good loca-tions for groundnut mottle virus-free seed pro-duction, probably because of the absence orpaucity of aphid vectors in that area.

Kuhn and Demski (1975) discussed the possi-bility of controlling groundnut mottle by insec-ticidal control of aphid vectors. However, theywere doubtful about the practicality of thisstrategy because the groundnut mottle virus istransmitted in a stylet borne fashion. The virusis acquired with one probe into an infectedepidermal cell. Therefore, the virus can betransmitted immediately and only for a shortperiod of time. It is also probable that the firstaphids arrive from outside of the groundnut fieldand thus cannot be easily eliminated prior toacquiring the virus from infected groundnutplants that originated from infected seed.

Tolin et al. (1970) reported that the incidenceof groundnut stunt was reduced whengroundnut fields were isolated from whiteclover. Culp and Troutman (1968) rated severalhundred A hypogaea cultivars, breeding lines,and introductions for their reaction togroundnut stunt. No immunity was reported,but symptoms were less severe on severalentries. Because of the low incidence ofgroundnut stunt in the United States there is noactive interest in the development of control measures.

Since spotted wilt is a minor groundnut dis-ease in only one groundnut producing state, noefforts have been made to develop controlmeasures. The possibility of disease resistanceis being considered by Ghanekar et al. (1979) atICRISAT.

Future Research Priorities

Because of the increasing costs of purchasing

and applying fungicides for management offoliar diseases in the United States, there is a need for new cultivars with multiple foliar dis-ease resistant, high yielding, good quality, andearly maturing traits. Rapid techniques forscreening large numbers of genotypes forresistance should be developed.

Additional information on the epidemiologyof individual foliar pathogens and interactionsamong foliar pathogens will be useful in thedevelopment of new foliar disease manage-ment strategies. A thorough study of the ecol-ogy of the non-pathogenic microflora of thegroundnut leaf surface may shed new light onour knowledge of the epidemiology of foliarpathogens.

There seems to be a growing sense ofoptimism that new groundnut cultivars withmultiple pest resistance can be developed. Theattainment of this objective will be a majorachievement in the area of groundnut cropimprovement.

References

ABDOU, Y. A. M., GREGORY, W. C, and COOPER, W. E.1974. Sources and nature of resistance to Cercos-pora arachidicola Hori and Cercosporidium per-sonatum (B. & C.) Deighton in Arachis species.Peanut Science 1:6-11.

BACKMAN, P. A., RODRIGUEZ-KABANA, R., and WILLIAMS,J. C. 1975. The effect of peanut leaf spot fungicideson the non-target organism, Sclerotium rolfsii Phytopathology 65: 773-776.

BACKMAN, P. A., RODRIGUEZ-KABANA, R., HAMMOND,J. M., CLARK, E. M., LYLE, J. A., IVEY, H. W., and STAR-LING, J. -G. 1977. Peanut leaf spot research inAlabama. Auburn University Bulletin 489. 38 pp.

BROMFIELD, K. R., and CEVARIO, S. J. 1970. Greenhousescreening of peanut (Arachis hypogaea) for resis-tance to peanut rust (fuccinia arachidis). Plant Dis-ease Reporter 54: 381-383.

CAMPBELL, W. V. 1978. Effect of pesticide interactionson the twospotted spider mite on peanuts. PeanutScience 5: 83-86.

CHOOPANYA, DUANGCHI. 1968. Distribution of peanutstunt virus in white clover in South Carolina and itsrelationship to peanut culture. Plant Disease Repor-ter 52: 926-928.

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CLARK, E., BACKMAN, P. A., and RODRIGUEZ-KABANA, R.

1974. Cercospora and Cercosporidium tolerance tobenomyl and related fungicides in Alabama peanutfields. Phytopathology 64: 1476-1477.

COOPER, W. E. 1966. A destructive disease of peanut.Plant Disease Reporter 50: 136.

CULP, T. W., and TROUTMAN, J. L. 1968. Varietal reac-tion of peanuts, Arachis hypogaea, to stunt virus.Plant Disease Reporter 52: 914-918.

DAVIS, D. D., and SMITH, D. H. 1976. Susceptibility of

peanut varieties to ozone. Proceedings of theAmerican Peanut Research and Education Associa-tion 8: 93. (Abs.).

DEMSKI, J. W., SMITH, D. H„ and KUHN, C. W. 1975.

Incidence and distribution of peanut mottle virus inpeanut in the United States. Peanut Science 2:91-93.

GHANEKAR, A. M., REDDY, D. V. R., IIZUKA, N., AMIN.

P. W., and GIBBONS, R. W. 1979. Bud necrosis ofgroundnut {Arachis hypogaea) in India caused bytomato spotted wilt virus. Annals of Applied Biology93: 173-179.

HALUWELL, R. S., and PHILLEY, G. L. 1974. Spotted wiltof peanut in Texas. Plant Disease Reporter 58:23-25.

HAMMONS, R. O. 1977. Groundnut rust in the UnitedStates and the Caribbean. PANS 23: 300-304.

HARRISON, A. L. 1972. Observations on the develop-ment and spread of peanut rust in South Texas in1971. Plant Disease Reporter 56: 873-874.

HASSAN, H. N., and BEUTE, M. K. 1977. Evaluation of

resistance to Cercospora leafspot in peanutgermplasm potentially useful in a breeding prog-ram. Peanut Science 4: 78-83.

HEBERT, T. T. 1967. Epidemiology of the peanut stuntvirus in North Carolina. Phytopathology 52: 1513-1516.

HORNE, C. W. 1974. Peanut disease atlas. Texas Ag-ricultural Extension Service, Texas A&M University,Texas, USA. MP-1170. 15 pp.

JACKSON, C. R., and BELL, D. K. 1969. Diseases of

peanut (groundnut) caused by fungi. University ofGeorgia College of Agriculture, Experiment StationResearch Bulletin 56. 137 pp.

JENKINS, W. A. 1938. Two fungi causing leaf spot ofpeanut. Journal of Agricultural Science 56: 317-332.

KORNEGAY, JULIA L, BEUTE, M. K., and WYNNE, J. C.

1980. Inheritance of resistance to Cercospora arachidicola and Cercosporidium personatum in sixVirginia-type peanut lines. Peanut Science 7: 4 -9 .

KUHN, C. W. 1965. Symptomatology, host range, andeffect on yield of a seed transmitted peanut virus.Phytopathology 55: 880-884.

KUHN, C. W. 1971. Peanut stunt virus in Georgia. PlantDisease Reporter. 55: 453.

KUHN, C. W., and DEMSKI, J. W. 1975. The relationship

of peanut mottle virus to peanut production. Uni-versity of Georgia Agricultural Experiment StationResearch Report 213. 19 pp.

KUHN, C. W., GROVERSOWELL, Jr., CHALKLEY, J. H., and

STUBBS, H. F. 1968. Screening for immunity topeanut mottle virus. Plant Disease Reporter 52:467-468.

KUHN, C. W., PAGUIO, 0. R., and ADAMS, D. B. 1978.

Tolerance in peanuts to peanut mottle virus. PlantDisease Reporter 62: 365-368.

LITTRELL, R. H. 1974a. Rhizoctonia foliar blight ofpeanuts. Journal of the American Peanut Researchand Education Association 6: 62 (Abs.).

LITTRELL, R. H. 1974b. Tolerance in Cercospora arachidicola to benomyl and related fungicides.Phytopathology 64: 1377-1378.

MERCER, P. C. 1977. Pests and diseases of groundnutsin Malawi. I. Virus and foliar diseases. Oleagineux32: 433-448.

MILLER, L. I. 1953. Studies on the parasitism of Cer-cospora arachidicola Hori and Cercospora per-sonate (B. & C). Ell. & Ev. Ph.D. thesis. University ofMinnesota, St. Paul, USA. 120 pp.

MILLER, L. I., and TROUTMAN, J. L. 1966. Stunt diseaseof peanuts in Virginia. Plant Disease Reporter 50:139-143.

PAGUIO, 0. R., and K UHN, C. W. 1974. Survey for peanutmottle virus in peanut in Georgia. Plant Disease Re-porter 58: 107-110.

PETTIT, R. E., RUTH ATABER., and HARRISON, A. L. 1973.

Ascochyta web blotch of peanuts. Phytopathology63: 447. (Abs.).

PHILLEY, G. L. 1975. Peanut web blotch: growth,pathogenesis and hosts of the causal agent, Mycos-phaerella argentinensis. Ph.D. thesis. Texas A&MCollege Station, Texas, USA. 116 pp.

191

PORTER, D. M. 1980. Increased severity of Sclarotinia blight in peanuts treated with captafol andchlorothalonil. Plant Disease 64: 394-395.

PORTER, D. M., GARREN, K. H„ MOZINGO, R. W., and VAN

SCHAIK, P. H. 1971. Susceptibility of peanuts toLeptosphaerulina crassiasca under field conditions.Plant Disease Reporter 55: 530-532.

ROGERS, K. M., and MIXON, A. C. 1972. Peanut stuntvirus in Alabama. Plant Disease Reporter 56: 415.

SHARIFF, Y., RAWLINGS, J. O., and G REGORY, W. C. 1978.

Estimates of leaf spot resistance in three in-terspecific hybrids of Arachis. Euphytica 27: 741 -751.

SMITH, D. H. 1972. Arachis hypogaea: a new host ofCristulariella pyramidalis. Plant Disease Reporter56: 796-797.

SMITH, D. H., and CROSBY, F. L. 1973. Aerobiology of

two peanut leaf spot fungi. Phytopathology63: 703-707.

SMITH, D. H., and LITTRELL, R. H. 1980. Management of

peanutfoliar diseases with fungicides. Plant Disease64: 356-361.

SMITH, D. H., and SEARCY, J. W. 1975. Absence of

benomyl tolerance in a collection of Cercospora arachidicola isolates. Proceedings of the AmericanPhytopathological Society 2: 141. (Abs.).

SMITH, D. H., MCGEE, R. E., and VESELY, L. K. 1978.

Isolation of benomyl-tolerant strains of Cercospora

arachidicola and Cercosporidium personatum atone location in Texas. Proceedings of the AmericanPeanut Research and Education Association 10-67.(Abs.).

SMITH, O. D., SMITH, D. H., and SIMPSON, C. E. 1979.

Web blotch resistance in Arachis hypogaea. PeanutScience 6: 99-101.

SOWEU, G., SMITH, D. H., and HAMMONS, R. 0. 1976.

Resistance of peanut plant introductions to Cercos-pora arachidicola. Plant Disease Reporter50: 494-498.

SUBRAHMANYAM, P., GIBBONS, R. W., NIGAM, S. N., and

RAO, V. R. 1980. Screening methods and furthersources of resistance to peanut rust. Peanut Science7: 10-12.

THOMPSON, S. S., and SMITH, D. H. 1972. Distribution

and significance of peanut rust in Georgia in 1971.Plant Disease Reporter 56: 290-293.

TOLIN, S. A., ISAKSON, 0. W., and TROUTMAN, J. L. 1970.

Association of white clover and aphids with peanutstunt virus in Virginia. Plant Disease Reporter54: 935-938.

VAN ARSDEL, E. P., and HARRISON, A. L. 1972. Possible

origin of peanut rust epidemics in Texas.Phytopathology 62: 794. (Abs.).

WOOOROOF, N. C. 1933. Two leaf spots of the peanut{Arachis hypogaea L) . Phytopathology 23: 627-640.

192

Research on Fungal Diseases of Groundnutat ICRISAT

P. Subrahmanyam, V. K. Mehan,D. J. Nevill and D. McDonald*

Many fungal diseases of groundnut are known(Jackson and Bell 1969; Garren and Jackson1973) and many fungi are reported to beclosely associated with groundnut fruits andseeds. Some of the diseases are of restricteddistribution but most are of common occur-rence throughout the Semi-Arid Tropics (SAT).At ICRISAT the main concern is with thosewidespread diseases that cause economicallyimportant losses in yield, and in this paperinvestigations carried out during the past 4 years on important foliar and soilborne dis-eases are briefly reviewed.

Foliar Diseases

Rust (Puccinia arachidis Speg.)

Previously unimportant outside the Americas(Bromfield 1971), rust is now of economic im-portance in almost all groundnut growing areasof the world (Hammons 1977; Subrahmanyamet al. 1979). Yield losses from rust may besubstantial and damage is particularly severewhere the crop is attacked by both rust and thelonger established Mycosphaerella leaf spots.

Investigations were carried out on the biologyof the rust fungus so as to determine whatfactors were likely to influence perpetuationand spread of the disease. Biological data werealso needed for development of methods forscreening germplasm for resistance to the dis-ease.

A wide range of crop and weed species werechecked for possible collateral hosts of rust butnone was found outside the genus Arachis.

The uredial stage only of the rust has beenfound although constant examination wasmade of many germplasm lines and some wild

* Pathologists, International intern, and PrincipalPlant Pathologist, respectively, Groundnut Im-provement Program, ICRISAT.

Arachis species at ICRISAT. Groundnut plantsfrom various parts of India have also beenexamined at every opportunity. Attempts toinduce teliospore formation by modification ofenvironmental factors were not successful. Itwas concluded that uredosporeswerethe main,if not the only, means of rust carry-over anddissemination in India.

Laboratory experiments showed thaturedospores could be stored for long periods atlow temperature without loss of viability butthat at high temperatures, they rapidly lostviability. For instance, when stored at 40°C theylost viability within 5 days. Uredospores onexposed crop debris lost all viability within 4 weeks under postharvest conditions atICRISAT. Pods and seeds from rust affectedcrops are commonly surface-contaminated withuredospores. Tests on uredospores taken fromsurface-contaminated seeds stored at roomtemperature showed viability to decrease froman original 95% to zero after 45 days. Impli-cations for disease carry-over and for plantquarantine are obvious. Rust is particularlysevere in South India where groundnuts aregrown in some areas at all times of the year.

Light was found to inhibit uredospore germi-nation and germ-tube elongation, indicatingthat field inoculation might be more successfulif carried out in the evening rather than throughthe day.

The presence of liquid water on the leafsurface was found to be necessary for uredos-pore germination and infection.

Preliminary rust resistance screening of theICRISAT germplasm collection (now over 8000entries) was carried out in the rainy seasons of1977, 1978 and 1979 under natural diseasepressure in the field. Infector rows and checkplots of the highly susceptible cv TMV-2 werearranged systematically throughout the trials.Entries which were rated between 1 and 5 on a 9-point disease scale (where 1 = no rust, and9 = 50-100% offoliagedestroyed by rust) were

193

selected for advanced f ield screening. This wasdone either in the rainy season as described orin the postrainy season when artif icial inocu-lation wi th uredospores and overhead irrigationto maintain high humid i ty were required toensure good deve lopment of rust. Genotypesfound to show good resistance to rust atICRISAT are l isted in Table 1 together w i t h their

Table 1. Genotypes resistant to rust atICRISAT.

Genotype

NC Acc 17090

Rust Scorea

2.0PI 414332 2.0PI 405132 2.5PI 341879 2.5PI 393646 2.5

NC Acc 17133-RF 3.0EC 76446 (292) 3.0PI 259747 3.0PI 350680 3.0PI 390593 3.0

PI 381622 3.0PI 393643 3.0PI 407454 3.0PI 315608 3.0PI 215696 3.0

PI 393641 3.0PI 314817 3.0PI 393517 3.0PI 414331 3.0PI 393527-B 3.0

NC Acc 927 3.3PI 390595 3.5PI 393531 3.5NC Acc 17127 3.8PI 393526 4.0

NC Acc 17129 4.0NC Acc 17132 4.0NC Acc 17135 4.0NC Acc 17124 4.0PI 298115 4.0

PI 393516 4.5NC Acc 17142 5.0Krap Str 16 5.0TMV-2b 9.0Robut 33-1* 9.0

mean rust scores on the 9-point scale. Scoresfor t w o susceptible cult ivars are included forcompar ison.

Wild Arachis species being g rown in the f ieldin close juxtaposi t ion w i t h severely rust af-fected groundnuts were examined at intervalsth rough the season for evidence of rust infec-t ion . Those species wh ich showed no develop-ment of rust are l isted in Table 2. A l though rustdid not develop on Arachis stenocarpa, somenecrotic lesions were fo rmed that may haveresulted f rom arrested invasion by the patho-gen.

Using artif icial inoculat ion, potted plants androoted detached leaves were used in screeningtrials in glasshouse and laboratory, respectively.The methods were effective in separatinggenotypes w i th large differences in resistance,e.g., highly resistant as opposed to susceptible,but were not suitable for showing any inter-mediate reactions.

In studies on components of resistance, it wasfound that neither size nor f requency of stomatawas correlated wi th resistance. Infection fre-quency was lower in resistant than in suscepti-ble genotypes and the incubat ion period waslonger. Irrespective of whether genotypes wereimmune, resistant, or susceptible, uredosporesgerminated on the leaf surface and germ-tubesentered the leaf via stomata. In immunegenotypes, the germ-tubes died w i thout furtherdevelopment. Differences in resistance weremanifest by differences in rate and degree ofdevelopment of the rust mycel ium in the sub-stomatal cavities and in invasion of leaf tissues.

Table 2. Wild Arachis spp on which no rustdeveloped in the field despite heavydisease inoculum.

a. Rust score on 9-polnt disease scale.b. Standard susceptible cultivars.

Species PI Number Section Source

A. duranensis 219823 Arachis ArgentinaA. correntina 331194 Arachis ArgentinaA. cardenasii 262141 Arachis BoliviaA. chacoense 276235 Arachis ParaguayA. chacoense X

A. cardenasii - F1 hybrid USAA. pusilla 338448 Triseminalae BrazilA. sp 9667 262848 Rhizomatosae BrazilA. sp 10596 276233 Rhizomatosae Paraguay

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Mycosphaerella or "Carcospora" Leaf Spots (Early Leaf Spot -Cercospora arachldlcola Hori;Late Leaf Spot — Cercosporidium personatum [Berk, and Curt.]Deighton)

The Mycosphaerella leaf spots are probably themost important diseases of groundnuts on a worldwide scale. Both are commonly presentand their relative importance is determined bycrop and environmental factors. At ICRISAT, thedisease incited by C. personatum is of regularoccurrence and reaches high levels on rainyseason groundnuts but that incited by C.arachidicola is much less common and rarelyreaches levels high enough to permit fieldresistance screening.

Field screening for resistance to the leaf spotswas carried out simultaneously with the rustscreening and a similar 9-point disease scalewas used. Entries rated between 1 and 5 wereselected for advanced field screening. All fieldscreening utilized natural inoculum. The dis-eases developed more rapidly and screeningwas more effective in the rainy season thanin the irrigated postrainy season crops.Genotypes found to have resistance to C. per-sonatum at ICRISAT are listed in Table 3.

Genotypes with field resistance to C. per-sonatum were further tested for resistance inglasshouse screening trials. Good correlationswere found between field and glasshouse testsin respect of defoliation, lesion size and sporu-lation index. Laboratory screening in whichrooted detached leaves were inoculated with C.personatum also proved useful. The lattermethod was also useful in the study of resis-tance mechanisms.

Both high resistance and immunity have beenfound among wild Arachis species (Table 4).The ICRISAT Groundnut Cytogeneticists haveproduced hybrids between some of the resis-tant wild species and the cultivated groundnut,and by backcrossing have obtained near tetra-ploid material which is being tested at all stagesfor resistance to leaf spots and to rust.

With leaf spots as with rust, germination ofspores and entry into the leaf via stomata didnot appear to be in any way inhibited in resis-tant genotypes. Resistance was again mani-fest in the postentry phase.

Table 3. Genotypes resistant to C. par-sonatum at ICRISAT.

Genotype Leaf spot score*

EC 76446 (292) 3.2NC Acc 17133-RF 3.3PI 259747 3.3PI 350680 3.3NC Acc 927 4.0

NC Acc 17127 4.3Krap Str 16 4.3RMP-91 4.7NC Acc 17090 4.8NC Acc 17130 4.8

NC Acc 17129 4.8NCAcc 17132 4.8NCAcc 17135 4.8NC Acc 17124 4.8RMP-12 5.0TMV-2b 9.0

«. Leaf spot score on 9-polnt disease scale.b. Standard susceptible cultlvar.

PI Number

Reaction to

Species PI Number C. arachidicola C. personatum

A. chacoense A. cardenasii A. sp 10596A. stenosperma

276325262141276233338280

Highly resistantSusceptibleImmuneHighly resistant

Highly resistantImmuneImmuneHighly resistant

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Table 4. Wild Arachls spp — reaction to Carcospora arachidicola and Cercosporidium par-aonatum.

Yie ld Losses f r o m Rust and Leaf Spo tsand M u l t i p l e Resis tance

Rust and leaf spots normally occur together andit is difficult to allocate individual responsibilityfor the resulting damage to the crop. In the 1979rainy season we attempted to estimate yieldlosses by applying fungicides to susceptibleand disease resistant genotypes; Daconil tocontrol leaf spots and rust, Bavistin to controlonly leaf spots, and Calixin to control only rust.Loss estimates are shown in Table 5. Losseswere less in the resistant than in the susceptiblegenotypes.

Comparison of Tables 1 and 3 will show thatsome of the genotypes resistant to rust are alsoresistant to C. personatum leaf spot. Also, somenew sources of resistance to both diseases haverecently been found in Federal Experiment Re-search Station — Puerto Rico (FESR) breedinglines (Table 6). These lines originated from a natural hybrid selected for resistance to rust inPuerto Rico by USDA scientists.

Some of the resistant genotypes can outyieldestablished Indian cultivars when grown with-out protective fungicide treatment at ICRISAT.Further work is required of breeders to incorpo-rate higher yields and better agronomic charac-ters into the resistant materials.

Other Fol iar Diseases

Some preliminary investigations have beenmade on what are at present regarded as minorfoliar pathogens. These include diseases incitedby Leptosphaerulina crassiasca (Sechet)

Table 5. Yield losses from rust and leaf spotsat ICRISAT.

Mean percentage loss of podyield from

Genotype Leaf spots RustLeaf spotsand rust

Robut 33-1a

PI 259747EC 76446 (292)NC Acc 17090

59301018

52231214

70373029

a. Standard auscaptlble cultivar.

Table 6. Genotypes resistant to rust and laafspot — FESR lines tested at ICRISAT.

Mean disease scores(9-point scale)

Genotype Rust Leaf spot

FESR 5-P2-B1 2.0 3.0FESR 5-P17-B1 2.0 3.0FESR 7-P13-B1 2.0 3.0FESR 9-P3-B1 2.0 3.0FESR 9-P4-B1 2.0 4.3

FESR 9-P7-B1 2.7 3.3FESR 9-P7-B2 2.7 4.3FESR 9-P8-B2 2.0 3.0FESR 9-P12-B1 2.0 2.7FESR 11-P11-B2 2.3 2.7

FESR 12-P4-B1 2.0 2.0FESR 12-P5-B1 2.0 2.7FESR 12-P6-B1 2.7 3.7FESR 12-P14-B1 2.0 3.3FESR 13-P12-B1 2.0 2.7TMV-2a 9.0 9.0

a. Standard susceptible cultivar.

Jackson and Bell, Alternaria alternata (Fr.) Keis-sler, and Myrothecium roridum Tode ex. Fr.

Soilborne Diseases

Seed and Seedling Rots

Seed rots and seedling diseases of groundnutare of common occurrence in the SAT and maycause serious losses in yield. The diseases maydevelop from fungi already established in theseeds before sowing, or may result from directinvasion of seeds or seedlings by soil fungi.Many species of fungi have been reported tocause seed rots and several are known to causediseases of seedlings. Some fungi causing dis-eases at ICRISAT are listed in Table 7.

Two important diseases of groundnut seed-lings are Crown Rot which is caused by Aspergil-lus niger van Tiegh and Aflaroot which iscaused by toxigenic strains of Aspergillus flavus Link, ex Fr. Initial screening of theICRISAT germplasm collection has indicated

196

Table 7. Fungi associated wi th seed andseedling diseases at ICRISAT.

Aspergillus flavus Link, ex Fr.Aspergillus niger van Tiegh.Botryodiplodia theobromae Pat.Fusariurn sppMacrophomina phaseolina (Tassi) Goid.Penicillium sppRhizoctonia solani KuehnSclerotium rolfsii Sacc.

that some genotypes may possess resistance tothese diseases.

Pod Rot

Pod rot diseases are widespread in the SAT andare known to cause severe damage in a numberof countries (Abdou and Khadr 1974; Frank1972; Mercer 1977; Porter et al. 1975). Highlevels of pod rot were observed in the 1978-79postrainy season crop at ICRISAT and screeningof germplasm for resistance was initiated.Some 2000 genotypes have now been screenedunder natural field disease conditions. Stan-dard local cultivars had 20-25% of pods rottedwhile disease levels in germplasm lines rangedfrom 4 to 72%. Genotypes with pod rot scores of10% or lower were selected for advancedscreening in disease sick plots.

The etiology of the disease is still beinginvestigated. Fungi commonly isolated fromrotted pods at ICRISAT are listed in Table 8.

Table 8. Fungi Isolated from rotted pods a ICRISAT.

Dominant species Fusarium solani (Mart.) Sacc.Fusarium oxysporum Schlecht

Subdominant Macrophomina phaseolina species (Tassi) Goid. Rhizoctonia

solani Kuehn

Associate species Aspergillus flavus Link, ex Fr.Aspergillus niger van Tiegh.Fusarium acuminatum Ell. & Ev.Fusarium equiseti (Corda) Sacc.Fusarium fusaroides

(Frag. & Cif.) BoothGliocladium roseum Bain.Trichoderma viride Pers. ex Fr.

The Aflatoxin Problem

Contamination of groundnuts with afIatoxins isa serious problem in many parts of the SAT. Theubiquitous Aspergillus flavus which producesthese toxic and carcinogenic substances mayinvade groundnut seeds before harvest, duringpostharvest drying, and during storage if theseeds are wetted. From the continued appear-ance of reports of aflatoxin contamination ofproduce it would appear that SAT farmers havenot adopted the crop handling and storagemethods designed to reduce aflatoxin contami-nation in groundnuts. It has therefore becomenecessary to investigate the possibilities ofgenetic resistance in the hope of developingcultivars with pods or seeds which A. flavus cannot invade, or which if invaded, do notsupport aflatoxin production.

Workers in the USA (Mixon and Rogers 1973;Bartz et al. 1978) have shown some genotypesto have high levels of resistance to A flavus invasion and colonization of dry seeds. This dryseed resistance is dependent upon the testabeing entire and undamaged. The test is a simple one. Mature undamaged seeds thathave been dried and stored for several weeksare placed in a petri dish and hydrated to20-25% water content. A suspension of A.flavus spores is added to them, and they areincubated for about 8 days. The percentage ofseeds which are colonized by the fungus indi-cates the degree of dry seed resistance posses-sed. The ICRISAT germplasm collection is nowbeing screened. The reactions of threegenotypes reported resistant in the USA andsome Indian cultivars are given in Table 9.

Table 9. Dry seed resistance to A. flavus col-onization.

Percentage of seeds col-onized by A. flavus and

Genotype disease testing

Resistant lines from USAUF 71513 7.0 ResistantPI 337394 F 9.1PI 337409 9.2

Indian cultivarsJunagadh 11 11.6TMV-2 35.0 SusceptibleOG 43-4-1 96.0 Highly susceptible

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There is no evidence th at the genotypes so farfound with dry seed resistance have any specialdegree of resistance to invasion of pods orseeds before harvest or during postharvestdrying. Investigations have started into possi-ble resistance during these phases, and particu-lar attention is being given to genotypes whichhave shown resistance to pod rots.

Some early research (Tulpule 1967; Kulkarniet al. 1967) indicated that certain cultivars hadresistance to the production of aflatoxin. How-ever, these findings were not confirmed byfurther research (Doupnik etal. 1969; Aujla et al.1978), although there were indications thatslight differences might exist between cultivarsin their ability to support aflatoxin production.In dry seed resistance testing at ICRISAT,toxigenic strains of A. flavus are used andgenotypes are being checked for possible dif-ferences in efficiency, as substrates for ana-toxins production.

Other So i l bome Diseases

A number of soilbome diseases occur regularlyat ICRISAT but at low incidence. These includewilt and root rot caused by species of Fusarium; a black root rot caused by Macrophomina phaseolina (Tassi) Goid; a root rot caused byRhizoctonia solani Kuehn; and stem rot causedby Sclerotium rolfsii Sacc. Disease sick plots arebeing established to allow screening of thegermplasm collection for possible resistance tothese diseases.

ReferencesABDOU, Y. A, and KHADR, A. S. 1974. Systemic control

of seedling and pod rot disease of peanut (Arachis hypogaea L). Plant Disease Reporter 58: 176-179.

AUJLA, S. S., CHOH AN, J. S., and M EHAN, V. K. 1978. Thescreening of peanut varieties for the accumulationof aflatoxin and their relative reaction to thetoxigenic isolate of Aspergillus flavus Link ex Fries.

Punjab Agricultural University Journal of Research15: 400-403.

BARTZ, J. A., NORDEN, A. J., LAPRADE, J. C, andDEMUYNK, T. J. 1978. Seed tolerance In peanuts[Arachis hypogaea L.) to members of the Aspergil-lus flavus group of fungi. Peanut Science 5: 53-56.

DOUPNIK, B. 1969. Aflatoxins produced on peanutvarieties previously reported to inhibit production.Phytopathology 59: 1554.

FRANK, Z. R. 1972. Notes on soil management inrelation to Pythium rot of peanut pods. Plant DiseaseReporter 56: 600-601.

GARREN, K. H., and JACKSON, C. R. 1973. Peanutdiseases. Pages 429-494 in Peanuts-culture anduses. American Peanut Research and EducationAssociation, Inc. Stillwater, Oklahoma 74074, USA.

HAMMONS, R. O. 1977. Groundnut rust in the UnitedStates and the Caribbean. Pest Articles and NewsSummaries 23: 300-304.

JACKSON, C. R., and BELL, D. K. 1969. Diseases ofpeanut (groundnut) caused by fungi. University ofGeorgia, College of Agriculture Experiment StationResearch Bulletin 56.

KULKARNI, L. G., SHARIEF, Y., and SARMA, V. S. 1967.Asiriya Mwitunde' groundnut gives good results atHyderabad. Indian Farming 17: 11-12.

MERCER, P. C. 1977. A pod rot of peanuts in Malawi.Plant Disease Reporter 61: 51-55.

MIXON, A. C, and ROGERS, K. M. 1973. Peanut acces-sions resistant to seed infection by Aspergillus flavus. Agronomy Journal 65: 560-562.

PORTER, D. M., GARREN, K. H., and VAN SCHAIK, P. H.1975. Pod breakdown resistance in peanuts. PeanutScience 2: 15-18.

RAO, K. S., and TULPULE, P. G. 1967. Varietal differencesof groundnut in the production of aflatoxin. Nature214: 738-739.

SUBRAHMANYAM, P., REDDY, D. V. R., GlBBONS, R. W.,RAO, V. R., and GARREN, K. H. 1979. Current distribu-tion of groundnut rust in India. Pest Articles andNews Summaries 25: 25-29.

198

Studies of Resistance to Foliar Pathogens

The training program at ICRISAT gives peoplethe opportunity to work for between 6 monthsand 2 years in research programs of theInstitute. In the groundnut program, there arethree postdoctoral fellows who have come fromJapan, UK and USA; there are three researchscholars working for M.Sc. degrees, fromBenin, Ghana and India; finally, this year,there have been in-service trainees from thePeople's Republic of China, Sudan and Tan-zania. This great diversity of workers has threemajor roles in the program: to gain experience;to familiarize staff members with newtechniques; and to carry out basic researchwhich may be outside the usual work ofICRISAT scientists. Since these last two rolesare particulary important for postdoctoral fel-lows, they will be emphasized in this paper.

Research Work

Groundnut rust, Puccinia arachidis Speg. andthe two leaf spot fungi, Cercospora arachidicola Hori and Cercospondium personatum (Berk. & Curt.) Deighton, are extremely importantpathogens of groundnuts. In the USA, the leafspot fungi have been successfully controlled byfungicides (Backman et al. 1977); however thisapproach may not be feasible in less developedcountries. The use of disease resistant varietiesis an alternative method of control, but in thepast it was thought that there was no usefulvariation in leaf spot resistance within thecultivated species (Abdou et al. 1974;Hammons 1973). However, recent work hasdemonstrated that such variation does exist(Sowell et al. 1976; Hassan and Beute 1977;Melouk and Banks 1978; Nevill 1979; Sub-rahmanyam et al. 1980). In this paper, studies

* International Intern, Groundnut ImprovementProgram, ICRISAT.

into the nature and utilization of this resistancewill be described.

Resistance to groundnut rust exists withi n thecultivated species (Mazzani and Hinojosa 1961;McVey 1965; Cook 1972), and at ICRISAT furtherstudies have been carried out to investigatescreening methods and the nature of the resis-tance response. These will also be describedhere.

The Potential of Disease ResistanceDuring the last two rainy seasons, the responseof 20 groundnut varieties to chemical diseasecontrol has been studied. Three fungicides havebeen used that control rust and leaf spot sepa-rately or together. Both diseases appear tocause similar yield losses (Table 1). Reductionin pod yield varied from 20 to 70% and if thislevel of resistance could be incorporated into a high yielding variety, such as Robut 33-1, thenyields of 4 t/ha could be achieved without theuse of fungicides.

It must be stressed that these results provideonly an indication of the potential of diseaseresistance, si nee the effects of the chemicals ongroundnut development and on the supposedlyuncontrolled fungus are not known. This experi-ment is in progress, and from the results,

Table 1. The response of four varieties tochemical disease control.

Percentage yield losscaused by Potential

yieldPotential

yieldVariety Rust Leaf spot Both (t/ha-1)

Robut 33- 1 27 38 70 4.8NC Acc 17090 14 17 30 3.4EC 76446 (292) 15 13 23 2.2PI 259747 10 18 37 2.0

199

D. J. Nevill*

multiple point models of disease developmentwill be derived which should improve crop lossassessment methods.

Laboratory Studiesof Leaf Spot ResistanceIn the laboratory, a simple detached leaftechnique is being used to study disease reac-tions in detail. Groundnut leaves have abscis-sion layers at the base of the leaflets and thepetiole. Excision through the pulvinus stimu-lates rooting without the application of hor-mones or specific nutrients if humid, moistconditions are maintained. Healthy leaves havesurvived for more than 3 months when culturedin moist sterile sand.

To use this technique in screening testsleaves were placed in plastic seed trays with thecut pulvinus buried in a layer of wet sand. Theadaxial surfaces of the leaves were inoculatedwith an aqueous spore suspension and whenthe leaves were dry, the trays were placed intransparent plastic bags for incubation. Thismethod has been found to provide a screen-ing technique for which little equipment orresources are required, but which reducesenviornmental variabi l i ty and avoids theconfounding effects of multiple infection.

Use of this techniqu e has demonstrated largevarietal differences in the expression of C.personatum symptoms, particularly in haloformation. Components of resistance to thisfungus, when estimated in the laboratory weresignificantly correlated with field scores of re-sistance based on a 0-9 scale. The characters— lesion diameter, incubation period, lesionnumber and defoliation — explained 54% ofthe variation in the field score when they wereincluded in a multiple regression analysis.This model has been able to rank 90% ofvarieties in a similar order to the field method. A better fit of the model would be achieved ifmore characters, such as latent period andsporulation, were included, but these are moredifficult to measure on a large number ofvarieties. Other reasons for the unexplainedvariation are inadequacies in the assumptionsof the regression model and imprecision in theestimates of the field scores.

For a small number of varieties, a completestudy of components of the C. personatum andC. arachidicola disease reactions has been con-

ducted. Resistance was associated with re-duced sporulation, longer latent periods andless defoliation, but the success of spores inproducing lesions did not differ between va-rieties. Sporulation from resistant varieties wasone-quarter to one-sixth that from susceptiblevarieties (Fig. 1) and latent periods were in-creased by 80%. These components havebeen integrated by means of a computer simu-lation model (Fig. 2). Using this technique,values of defoliation, leaf damage and sporeproduction are estimated for each day of a simulated growing season. The model predictsthat defoliation caused by the leaf spot patho-gens can be eliminated by use of the resistancelevels that exist within A. hypogaea. The com-puter program is being refined to improve therealism of the model.

Figure 1.

LABORATORY

Days from inoculation

Daily spore production arachidicola lesions.

from C.

SYSTEM CONSTRAINTS

Onset Environment

PREDICTED

FIELD DATA

Figure 2. Diagrammatic representation of the simulation model.

200

Laboratory Studies of Rust Resistance

The detached leaf technique has also been usedto study rust resistance. In this case it was foundthat most of the resistance components whichwere estimated in the laboratory were notcorrelated with a field score (0-9 scale). Onlyone character, i.e., numbers of lesions, gave a significant regression and only 19% of thevariation in the field score was explained. It wastherefore concluded that only the most resistantand susceptible varieties could be separatedreliably by this technique. It is likely that thephysiology of interaction between P. arachidis and its host is extensively altered after excisionof the leaves.

Some basic histological studies are beingcarried out to investigate the nature of rustresistance in the cultivated species. Events dur-ing penetration and early mycelial developmentare being studied using leaf clearing and stain-ing methods. The mortality of developing rustinfections has been estimated using an ap-proach similar to the life-table analysis ofhuman populations and some results areshown in Fig. 3.

The percentage survival of two populations ofuredospores on leaves of a resistant and a susceptible variety declined during infection.Despite the occurrence of the highest mortalityduring penetration, resistance was expressedlater, during colony development. Similarly, instudies of immune wild species, P. arachidis

Days after germination

Figure 3. Mortality of P. arachidis during the infection process (AP, Appres-sorium formation; SSV, sub-stomatal vesicle formation; EH, the production of an elongating hypha).

was able to penetrate through stomata, but inthis case development ceased after the forma-tion of a single hypha out of the substomatalvesicle.

There appear to be differences betweenspecies in the different sections of the genus intheir ability to penetrate (Table 2). These effectsare still being studied, since it may be possibleto introduce new types of resistance into thecultivated species, particularly from sectionRhizomatosae of the genus.

The Genetic Controlof Leaf Spot Resistance

The genetic control of leaf spot resistance isbeing studied in both field and laboratory experi-ments. Parents were selected using detachedleaf tests in April 1979 and F2 progenies werescreened as detached leaves during the post-rainy season of 1979-80. Thus, by using thistechnique, three generations have been grownand one generation has been tested within oneyear. If field tests of the selected F3 progeniesare successful, the technique should be a usefultool in rapid cycle backcross and recurrentselection breeding methods.

In the F2 progenies, a great range of diseasereactions was observed and all components ofresistance were inherited in a quantitativemanner. Defoliation was controlled by geneswith additive action, but for other components,dominance effects were important and resis-tance was recessive (Fig. 4). From the numbers

Table 2. Percentage survival of groundnutrust during the Infection of threeArachis species.

State of the infection process*

Species GT AP SSV EH CF

A. hypogaea (cv TMV-2)

A. chacoense A. glabrata

100

100100

57

5039

35

3510

30 30

30 0 8 0

a. GT, germ tube formation (assumed value); AP, appres-sorium formation over a stoma; SSV, the production of a sub-stomatal vesicle; EH, the production of an elongatinghypha; CF, colony formation.

201

Figure 4. The frequency distribution of an F2 population derived from crossing Robut 33-1 and Krapovickas Strain 16.

of resistant segregates, it is likely that genes at 3 or 4 loci are controlling the disease reaction.The results of these tests are being confirmed infield trials this season.

Furthergenetical studies which involve dialleland line x tester crossing systems, are beingconducted in the field. The results of this sea-son's trials should provide a good deal ofknowledge about the genetics of leaf spot andrust resistance and also the relationship of thisresistance to plant yield.

Conclusion

During this project, a number of new techniqueshave been developed and demonstrated. Inparticular, tests of detached leaves have beenused to study disease reactions of F2 progeniesand computer modelling has been employed toinvestigate the relationship between field andlaboratory results. Fundamental studies of thenature of resistance have been initiated andhave provided a necessary basis for the moreapplied aspects of ICRISAT research. Thisbriefly demonstrates the ways in which a post-doctoral fellowship can contribute to thegroundnut research program.

References

ABDOU, Y. A. M., GREGORY, W. C, and COOPER, W. E.

1974. Sources and nature of resistance to Cercos-pora arachidicola Hori and Cercosporidium per-sonatum (B&C) Deighton in Arachis species. PeanutScience 1: 6-11.

BACKMAN, P. A., RODRIGUEZ-KABANA, P.., HAMMOND,

J. M., CLARK, E. M., LYLE, J. A., IVEY, H. W., and

STARLING, J. G. 1977. Peanut leaf spot research inAlabama 1970-76. Bulletin 489, Agricultural Exper-iment Station, Auburn, Alabama, U.S.A.

COOK, M. 1972. Screening of peanut for resistance topeanut rust in the greenhouse and field. PlantDisease Reporter 56: 382-386.

HAMMONS, R. O. 1973. Genetics of Arachis hypogaea. Chapter 4 in Peanuts culture and uses. AmericanPeanut Research and Education Society.

HASSAN, H. N., and BEUTE, M. K. 1977. Evaluation of

resistance to Cercospora leaf spot in peanut poten-tially useful in a breeding program. Peanut Science4: 78-83.

MCVEY, D. V. 1965. Inoculation and development ofrust on peanuts grown in the glasshouse. PlantDisease Reporter 49: 191-193.

MAZZANI, B., and HINOJOSA, S. 1961. Differencias va-

rietales de susceptibilidad a la roya del mani enVenezuela. Agronomie Tropicale 11: 41-45.

MELOUK, H. A., and BANKS, D. J. 1978. A method of

screening peanut genotypes for resistance to Cer-cospora leafspot. Peanut Science 5: 112-114.

NEVILL, D. J. 1979. An investigation of disease reactionto Cercosporidium personatum in Arachis hypogaea. Tropical Grain Legume Bulletin 15:18-22.

SUBRAHMANYAM, P., McDONALD, D., GIBBONS, R. W.,

NIGAM, S. N., and NEVILL, D. J. 1980. Resistance to

both rust and late leaf spot in some cultivars ofArachis hypogaea. Proceedings of the AmericanPeanut Research and Education Society 12 (inpress).

202

Lesion diameter (mm)

International Aspectsof Groundnut Virus Research

D. V. R. Reddy*

Several virus diseases of groundnut occur in theSemi-Arid Tropics (RAT) (Chohan 1974; Feakin1973; lizuka et al. 1979; McDonald and Raheja1980) and some are economically important(Gibbons 1977; lizuka et al. 1979). Peanut mottlevirus (PMV) is the most widespread (Reddy et al.1978) and can cause considerable yield losses(Kuhn and Demski 1975). Other economicallyimportant virus diseases have more restricteddistributions. For instance, groundnut rosette isimportant in Africa, south of the Sahara (Gib-bons 1977; Gillier 1978; Rossel 1977; Yayock etal. 1976); peanut clump (PCV) in West Africa(Trochain 1931; Bouhot 1967; Germani et al.1975) and in India (Reddy et al. 1979); budnecrosis (caused by tomato spotted wilt virus-TSWV) in India (Ghanekar et al. 1979); andwitches' broom (a disease associated withmycoplasma-like organisms) in Southeast Asia(lizuka, personal communication).

Applied research on plant virus diseases dif-fers from that on fungal and bacterial diseasesbecause of the special nature of viruses. Someimportant prerequisites to the eventual controlof virus diseases are characterization of thecausal virus and elucidation of its mode oftransmission. Precise virus characterization in-volves complicated techniques which are con-stantly being improved as a result of rapidtechnological advances and increasing interestin the mode of replication of plant viruses.

For effective management of plant virus dis-eases it is essential that their ecology is under-stood. The distribution of each disease shouldbe ascertained and yield losses assessed. Highpriority should be given to screening for hostplant resistance and production of resistantcultivars and this depends on close cooperationwith scientists in other disciplines. To enablethese aims to be achieved it is necessary that

* Principal Virologist, Groundnut ImprovementProgram, ICRISAT

simple and effective techniques should be de-veloped for the detection and identification ofviruses.

Problems of Virus Researchin the Semi-Arid Tropics (SAT)

Most reports on the occurrence of groundnutvirus diseases in the SAT have been basedlargely upon visual symptoms. However, it iswell known that external symptoms can begreatly influenced by such factors as genotype,plant age, environment, and strain of viruspresent. On the basis of symptoms alone itappears that bud necrosis in India (Ghanekar etal. 1979) has been described under six differentnames; each being regarded as a new diseaseby the authors. Again, on the basis of externalsymptoms, rosette has been reported fromIndia, the Philippines, Indonesia, Australia,Russia and Argentina (Rossel 1977).

For most areas of the SAT, data on theincidence and distribution of groundnut virusdiseases are either incomplete or lacking.Causal viruses, with very few exceptions (Bock1973; Germani et al. 1975; Dubern and Dollet1978 and 1979) have not been fully charac-terized. This is true even for groundnut rosettevirus which has been under investigation inAfrica for almost half a century. Reports onlimited characterization of this virus (Okusanyaand Watson 1966; Hull and Adams 1968) are yetto be confirmed.

Losses due to diseases have been reliablyassessed for only few groundnut virus diseases,including those which have been characterized.

Methods for screening groundnutgermplasm for resistance to viruses (and totheir vectors) have been developed for only a few diseases, and only in the case of groundnutrosette has there been successful developmentof resistant cultivars (Gibbons 1977; Gillier1978; Harkness 1977).

203

The most important objectives of the ICRISATprogram are to characterize the economicallyimportant virus diseases in the SAT and topresent reliable data on their distribution andinterrelationships with similar viruses occur-ring in other countries.

In order to provide a basis for the control ofvirus diseases, research should be pursuedinto: (1) screening for disease resistance inArachis hypogaea and in wild Arachis sp; (2) theeffect of cultural practices (including date ofsowing, spacing and intercropping) on the inci-dence and spread of disease; and (3) avoidingsources of infection.

Diagnosis of Groundnut VirusDiseases

Various steps involved in the diagnosis of plantvirus diseases (Bos 1976) are given in Table 1.

Table 1. Steps in the diagnosis of plant virusdiseases*

Assessment of economic importance (incidence,distribution, and yield losses).Transmission by grafting, sap inoculation, in-sects, nematodes, etc.Inoculation to a series of test plants (preferably bymechanical sap inoculation) and back inoculationto a parallel range of test plantsto check possiblemultiple infection and host range.Identification of a host which consistently pro-duces characteristic symptoms, especially locallesions (diagnostic host).Identification of a systemically infected hostwhich supports high virus concentration (forpurification of viruses).Determination of biological properties using locallesion, assay (TIP, LIV and DEP).Examination under electron microscope (leaf dip,thin sections).Testing by serological methods.Development of methods to purify the virus.Determination of physico-chemical propertiesand electron microscopy of purified virus.Production of antiserum.Testing of serological relationships with similarviruses occurring elsewhere.Fulfillment of Koch's postulates, especially usingpurified virus.

.. Modified from Bos (1976).

Although it will eventually be necessary todiagnose virus diseases of minor importance,characterization of economically importantgroundnut virus diseases (bud necrosis, clumpand peanut mottle) has to receive top priority.

Sap InoculationIn initial stages, sap transmission of virusespresent in crude groundnut leaf extracts couldbe achieved by adding reducing agents such as2-mercaptoethanol to extracting buffers. In ad-dition, maintenance of low temperaturethroughout the inoculation process, determi-nation of optimum ionic strength and pH of phos-phate buffer, and the selection of only younginfected leaflets showing certain characteristicsymptoms, have facilitated mechanical sap in-oculation of all groundnut viruses isolated sofar in India.

Diagnost ic Hosts

A large number of hosts commonly used in thediagnosis of virus diseases have been securedand are being maintained. From these, diag-nostic hosts have been selected for each of thevirus diseases characterized at ICRISAT.

Serology

If virus antisera are available, serologicaltechniques (Ball 1974; van Regenmortel 1978)offer effective means of diagnosis. They arerapid and can easily be standardized for thedetection of specific viruses. Conventionalserological techniques such as tube precipitin,micro-precipitin and precipitin ring tests havebeen used but have serious limitations for workwith groundnut viruses. For instance, they werenot successful when used for detection ofTSWV in groundnuts because of limitationssuch as low virus concentration in plant extractsand lack of high titred antisera.

Three other serological techniques that havebeen used at ICRISAT with considerable suc-cess are Ouchterlony's agar gel double-diffusion (AGD); passive haemagglutination(PHA); and enzyme-linked immunosorbentassay (ELISA).

In the AGD test, antigen and antibody areallowed to diffuse into agar. A positive reactionresults in the appearance of a thin white band

204

1.

2.

3.

4.

5.

6.

7.

8.

9.10.

11.12.

13.

where antigen and antibody meet. The test iseasy to perform and requires no specializedequipment (Ball 1974). It can be used to testseveral samples at the same time. By using theslight modification of incorporating 3,5-diiodosalycilic acid into the agar for dissociat-ing long rod-shaped viruses, the test has beensuccessfully employed to detect PMV andCowpea mild mottle virus (CMMV) (Table 2).

The PHA test (Ball 1974), one of the mostsensitive serological techniques, has been sim-plified and modified to prevent non-specificagglutination (Rajeswari et al„ in press).Glutaraldehyde-fixed red blood cells, aftertreatment with tannic acid, are coated withantiserum. Antibody sensitized red blood cellsare then added to various dilutions of testsolutions. The test is performed in lucite platescontaining 'U'-shaped wells and in a positivereaction red cells agglutinate, forming a smooth

mat with a serrated margin on the bottom of thewell. In a negative reaction, red cells form a discrete red ring at the periphery of the well.

The PHA test is extremely sensitive, easy tooperate, does not need specialized equipmentor reagents, and requires much less antiserathan the AGD test. The PHA technique can beused to detect viruses in crude plant extracts.The test has been successful in the detection ofTSWV antigens in infected groundnut plantsand in the thrips vector. The test has also beensuccessfully used for the detection of othereconomically important virus diseases in India(Table 2).

Both AGD and PHA techniques were tried fordetection of viruses in seeds but without suc-cess. The ELISA technique was acquired andsuccessfully adopted for detection of PMV inseed (Reddy et al., in preparation). The ELISAtest is by far the most sensitive and specific

Table 2. Characterization of important viral dlseases of g roundnut in India.

Name of the virus

characterization TSWV PCV PMV CMMV

1. SerologyGel diffusionHaemagglutinationELISA

?+

++#

+++

++*

2. Electron microscopyPlant materialPurified virus

+*

*+

++

#+

3. TransmissionMechanicalVectorSeed

++

++?

+++

+?

4. Physicochemical propertiesSedimentation coefficientM.W. of proteinM.W. of nucleic acid

#«#

#+*

+++

*++

5. Host range + + + +

6. Biological propertiesTIPLIV

++

++

++

++

7. SymptomsGroundnutDiagnostic host

++

++

++

++

+ = Positive result, - - Negative result. *= Not performed, ? > > Data Inconclusive

205

serological technique now available for detec-tion of plant viruses (Clark and Adams 1977;Voller et al. 1976). The procedure is simple andrapid. The y-globulins extracted from antisera,are absorbed to welts of a special microtiterplate. Test samples, including crude plant ex-tracts, purified viruses and extracts from seed,are added to the wells. If the test samplecontains specific viral antigens, theseare boundtothe y-globulins coated on the inner surface ofthe well. Thetest samples are washed away andenzyme-conjugated y-globulins are added tothe wells. The labelled antibodies bind to theviral antigen already bound to the y-globulinscoated on the plastic surface. Finally, a sub-strate for the enzyme, which was used earlierfor conjugating '/-globulins is added to the well.The color change in the substrate is propor-tional to the amount of enzyme present, whichin turn is proportional to the viral antigenconcentration.

The two major limitations of ELISA are theneed for high titered antisera and specializedreagents and plates for performing the test.Using the ELISA technique, it has been possibleto screen nearly 1000 kernels for presence ofPMV in two days. It would take nearly onemonth to field plant seed and score visually forPMV symptoms. A small portion of the cotyle-don is adequate for detecting the virus. Inaddition, PMV could be detected in crude plantextracts d iluted to 1:10000.

Experiments are under way to employ ELISAfor the detection of other groundnut virusesand especially for monitoring field collectedviruliferous vector populations.

Electron MicroscopyElectron microscopy is an essential techniquefor the detection and identification of plantviruses. An electron microscope has recentlybeen installed at ICRISAT and facilities areavailable for fixation, embedding and thin sec-tioning of plant material. Purified preparationsof PCV, PMV and CMMV have been examined.Tomato spotted wilt virus and PMV could belocalized in thin sections of infected plant mate-rial.

Pur i f icat ion

Purification of plant viruses is essential to

produce antisera, for determining physico-chemical properties and for electron micros-copy. Purification of viruses requires expensivelaboratory equipment such as a refrigeratedsuperspeed centrifuge, an ultracentrifuge, a spectrophotometer and a gradient scanner. Inaddition, expertise is required for virus purifi-cation. However, with the aid of a refrigeratedsuperspeed centrifuge it would be possible topartially purify viruses and prepare electronmicroscope grids for examination at ICRISAT.

Several physicochemical techniques arenow available for separating virus particlesfrom the normal constituents of their host cell,and the art of purification is to exploit thesetechniques so as to produce highly infectivevirus preparations as free as possible from hostmaterial. Groundnut tissue contains an excessof tannins which normally interfere in viruspurification. At least one more suitable host hasbeen discovered for each one of the groundnutviruses characterized at ICRISAT for use in viruspurification. Various buffers, with specific ionicstrength and pH values, have been used suc-cessfully to stabilize viruses in the initial puri-fication steps which involve extraction from theleaves, clarification with organic solvent, pre-cipitation with polyethylene glycol (PEG) andsubsequent resuspension of PEG precipitates.Further purification has been achieved in rateand quasi-equiiibrium zonal density gradientcentrifugation in sucrose solutions.

Purification techniques specific for PMV, PCVand CMMV have been developed to obtain highvirus yields and high specific infectivity with nodetectable impurities (Table 3). Tomato spottedwilt virus is known to be one of the most difficultviruses to purify, but a purification methoddeveloped at ICRISAT should soon be available.

Phys icochemica l Proper t ies

Specialized skills and experience, and specialequipment, are required to characterize virusesby physico-chemical methods. Thesetechniques usually complement the results ofelectron microscopy and serology but are in-dispensable in determining relationshipsamong similar viruses and in distinguishingstrains. Molecular weight determination of viralproteins and nucleic acids employing polyac-rylamide gel electrophoresis (Adesnik 1971;Maizel 1971; Reddy and Black 1973; Reddy and

206

Table 3. Virus purification methods davalopad at ICRISAT Center.

To obtain: High virus yields For: Peanut mottle virusNo detectable impurities Cowpea mild mottle virusHigh specific infectivity Peanut green mosaic virus

Peanut clump virusTomato spotted wilt virus

MacLeod 1976) has now become an indispens-able tool for rapid characterization of viruses.

Chemical characterization has been success-fully employed at ICRISAT to distinguish themorphologically identical PMV and peanutgreen mosaic virus (both belong to the potatovirus Y group) and the morphologically similarCMMV which belongs to the Carla Virus group)(Table 2).

General

The important criteria employed in the charac-terization of groundnut viruses are given inTable 4. A series of occasional papers, describ-ing details of all the steps involved in each ofthe techniques employed for the diagnosis ofgroundnut viruses at ICRISAT, is under prepa-ration.

Table 4. Diagnosis of v i rus diseases.

Identification depends onSerologyElectron microscopyTransmissionPhysicochemical propertiesHost rangeSymptomatology

Management of Virus Diseases

With the exception of PCV and CMMV thevectors of all groundnut viruses, characterizedat ICRISAT, have been identified (Table 5).Studies on various factors contributing to themultiplication and spread of vectors have pro-vided us with ways and means of managing thediseases. For instance, cultural practices (dateof sowing, and plant spacing) have been suc-cessfully employed to reduce losses from budnecrosis (TSWV). In addition, identification of

Table 5. Vectors of virus diseases identifiedat ICRISAT Center.

1. Bud necrosis : Scirtothrips dorsalis (Tomato spottedwilt virus)

Frankliniella schultzei

2. Peanut mottle : Aphis craccivora Myzus persicae

3. Peanut clump : Nematodes (?)4. Yellow spot (Tomato

spotted wilt virus?): Scirtothrips dorsalis

5. Peanut green mosaic : Aphis gossypii Myzus persicae

vectors and virus-vector relationship have beenhelpful, in the diagnosis of TSWV and PMV.Large scale methods for screening germplasmhave been developed and sources of resistancehave been identified for some viruses.

Groundnut Virus Researchin the SAT

The techniques described for detection, iden-tification and purification of viruses requireelaborate and expensive equipment (Table 6)and availability of highly trained scientific andtechnical staff. The virus laboratory at ICRISATand a relatively small number of otherlaboratories in the SAT are so equipped. Itwould not be practical to set up suchlaboratories in all areas of the SAT whereresearch on groundnut viruses is considereddesirable. However, the absence of a fullyequipped and staffed virus laboratory does notmeanthat useful research ongroundnutvirusescannot be undertaken.

Groundnut virologists from ICRISAT, or fromother institutions where specialized virus re-search is being undertaken, could visit differentareas of the SAT and in collaboration with

207

Table 6. Requirements for virology research.

1. Maintenance and transmission*Glass or screenhouse*Autoclave

II. Serology*Clinical centrifuge*Hot water bathSpecial chemicals, plates

III. Production of antisera*Animal house*Rabbits

IV. Diagnosis*Diagnostic hosts

Chemical characterizationElectrophoresis apparatus

•SpectrophotometerV. Purification

•Ref. superspeed centrifugeUltracentrifugeGradient scanner

VI. Electron microscopyFixing and embeddingElectron microscopeVacuum coating deviceUltra microtome

* Essential

national scientists carry out surveys to deter-mine the occurrence and distribution of impor-tant groundnut virus diseases. The basictechnology for such work could readily beprepared at ICRISAT and taken to the surveyareas. This would include a supply of seed ofdiagnostic hosts, antisera for use with PHA andELISA techniques and fixatives to prepare tis-sues for eventual electron microscopy.

Antisera can be stored for long periods at lowtemperature without considerable loss of theirtiters. Gluteraldehyde-fixed red blood cells canbe held at room temperatures for at least a week, without impairing their suitability forsensitization; and if kept at low temperaturesthey are suitable for use in the PHA test after 3 months of storage.

If it were desired to test seeds or plant tissuesfor the presence of PMV, the ELISA techniquecould be employed. At ICRISAT, y-globulinsand enzyme labelled y-globulins could be pre-pared and taken to the laboratory where testswere to be done. These preparations can bekept at room temperature for 10 days without

damage and stored at low temperature for overa year.

Where no electron microscope facility isavailable locally, it would be possible to fix andembed plant tissues for later sectioning andexamination at ICRISAT. Where no facilities forfixation and embedding exist, it would besufficient to infiltrate portions of plant tissueswith gluteraldehyde; this process being carriedout at reduced atmosphere pressure. Suchmaterials could be shipped to ICRISAT, oranother laboratory with electron microscopyfacilities.

Problems could arise where an importantvirus disease was of relatively restricted dis-tribution and where no fully equipped viruslaboratory was available to carry out viruspurification and production of antisera.

Irrespective of the presence of a similar dis-ease in India, it would not be possible for suchwork to be carried out at the ICRISAT Centerbecause of plant quarantine laws prohibitingthe importation of live viruses. This problemcould be solved if virus laboratories in techni-cally advanced countries where groundnuts arenot grown could cooperate in purification andantisera production. A number of suchlaboratories have already shown interest insuch cooperation.

Cooperation is also envisaged between viruslaboratories in the exchange of antisera, seed ofdiagnostic hosts, and other materials useful invirus identification. Every effort should be madeto expedite publication of research findings andin particular to make available data on newtechniques.

An important part of the work of ICRISAT isthe collection, recording and dissemination ofresearch data and the provision of specializedtraining and opportunities for cooperative re-search. As already mentioned, papers are beingprepared on the various techniques used in thegroundnut virus research laboratory. Trainingcan be given on these techniques and on otherrelevant techniques in the associated fields ofentomology (identification and control of virusvectors), plant breeding (screening ofgermplasm and production of resistant cul-tivars) and cytogenetics (utilization of wildArachis species as sou rces of resistance to virusdiseases). It can also be arranged for virologiststo make visits of varying duration to ICRISAT todiscuss collaborative projects, acquire exper-

208

tise in specific techniques, or to process theirown research materials.

References

ADESNIK, M. 1971. Polyacrylamide gel electrophoresisof viral RNA. Pages 126-175/W Methods in virology(K. Maramorosch and H. Koprowski eds.) Vol. 5.Academic Press, New York.

BALL, E. M. 1974. Serological tests for the identifica-tion of plant viruses. American PhytopathologicalSociety. St. Paul, USA. 1-30 pp.

BOCK, K. R. 1973. Peanut mottle virus in East Africa.Annals of Applied Biology 74: 171-179.

Bos, L. 1976. Research on plant virus diseases in de-veloping countries: Possible ways for improve-ment. FAO Plant Protection Bulletin 24: 109-118.

BOUHOT, D. 1967. Observations sur quelques affec-tions des plantes cultivees au Senegal. AgronomieTropicale Nogent 22: 888-890.

CHOHAN, J. S. 1974. Recent advances in diseases ofgroundnut in India. Pages 171-184 in CurrentTrends in Plant Pathology, (eds. S. P. Raychaudhuriand J. P. Verma). Lucknow University, India.

CLARK, M. F., and ADAMS, A. N. 1977. Characteristics ofthe microplate method of enzyme linked im-munosorbent assay for the detection of plant vi-ruses. Journal of General Virology 34: 475-483.

DUBERN, J., and DOLLET, M. 1978. Observation d'unenouvelle maladie a virus en Cote - d'lvoire: lamaladie des taches ocetlees de I'arachide.Oleagineux 33: 175-177.

DUBERN, J., and DOLLET, M. 1979. Groundnut crinkle, a new virus disease observed in Ivory Coast.Phytopathologische Zeitschrift 95: 279-283.

FEAKIN, S. D. 1973. Pest control in groundnuts. Pages81-89 in PANS Manual No. 2. Centre for OverseasPest Research, London, UK.

GERMANI, G.,THOUVENEL, J. C, and DHERY, M. 1975. Lerabougrissement de I'arachide. Une maladie a virusau Senegal et en Haute-Volta. Oleagineux30: 259-266.

GHANEKAR, A. M., REODY, D. V. R., IIZUKA, N., AMIN,P. W., and GIBBONS, R. W. 1979. Bud necrosis ofgroundnut (Arachis hypogaea) in India caused bytomato spotted wilt virus. Annals of Applied Biol-ogy 93: 173-179.

GIBBONS, R. W. 1977. Groundnut rosette virus. Pages19-21 in Diseases, pests, and weeds in tropicalcrops. Edited by J. Kranz, H. Schumtterer, and W.Koch. Verlag Paul Parey, Berlin.

GILLIER, P. 1978. Nouvelles limites des culturesd'arachides resistantes a la secheresse et a larosette. Oleagineux 33: 25-28.

HARKNESS, C. 1977. The breeding and selection ofgroundnut varieties for resistance to rosette virusdisease in Nigeria. Report submitted to the AfricanGroundnut Council.

HULL, R., and ADAMS, A. N. 1968. Groundnut rosettevirus and its assistor virus. Annals of Applied Biol-ogy 62: 139-145.

IIZUKA, N., REDDY, D. V. R., and GHANEKAR, A. M. 1979.Identification of some viral diseases of groundnut inIndia. Paper presented at the Legumes in Tropicssymposium, Malaysia.

KUHN, C. W., and DEMSKI, J. W. 1975. The relationshipof peanut mottle virus to peanut production. Re-search Report. Agricultural Experiment Station,University of Georgia, USA.

M AIZEL, J. V. 1971. Polyacrylamide gel electrophoresisof viral proteins. Pages 179-246 in Methods in Vir-ology (K. Maramorosch and H. Koprowski eds). Vol.5. Academic Press. New York.

MCDONALD, D., and RAHEJA, A. K. 1980. Pests, dis-eases, resistance and crop protection ingroundnuts. In Advances in legume science (eds.Summerfield and Bunting). Vol. 1. Proceedings ofthe International Legume Conference, Kew, Eng-land.

OKUSANYA, B. A. M., and WATSON, M. A. 1966. Hostrange and some properties of groundnut rosettevirus. Annals of Applied Biology 58: 377-387.

RAJESHWARI, R., REDDY, D. V. R., and IIZUKA, N. 1981.Improvements in the passive haemagglutinationtechnique for serological detection of plant viruses.Phytopathology (In press).

REDDY, D. V. R., and BLACK, L. M. 1973. Electrophoreticseparation of all components of the double-stranded RNA of wound tumor virus. Virology54: 557-562.

REDDY, D. V. R., and MACLEOD, R. 1976. Polypeptidecomponents of wound tumor virus. Virology70: 274-282.

REDDY, D. V. R., IIZUKA, N„ GHANEKAR, A. M., MURTHY,V. K., KUHN, C. W., GIBBONS, R. W., and CHOHAN, J. S.

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1978. The occurrence of peanut mottle virus In India.Plant Disease Reporter 62: 978-982.

REDDY, D. V. R., llZUKA, N., SUBRAHMANYAM, P.,RAJESHWARI, R., and MCDONALD, D. 1979. A soil-borne disease of peanut in India. Proceedings ofAmerican Peanut Research and Education Society11: 49.

REDDY, D. V. R., LISTER, R. M., and RAJESHWARI, R.Detection of peanut mottle virus in peanuts employ-ing enzyme linked immunosorbent assay (In pre-paration).

ROSSEL, H. W. 1977. Some observations and experi-ments on groundnut rosette virus and its control inNigeria. Miscellaneous paper 71. Institute of Ag-ricultural Research, Samaru, Nigeria.

TROCHAIN, J. 1931. La "Lepre de I'Arachlde. Revue DeBotanique Appliquee Et Agriculture Tropicale11: 330-334.

VANREGENMORTEL, M. H. V. 1978. Application of plantvirus serology. Annual Review of Phytopathology16: 57-81.

VOLLER, A. M., BIDWELL, D. E., and BARTLETT, A. 1976.Enzyme immunoassays in diagnostic medicine. Bul-letin of World Health Organization 53: 55-65.

YAYOCK, J. Y., ROSSELL, H. W., and HARKNESS, C. 1976.A review of the 1975 groundnut rosette epidemic inNigeria. Paper presented at the African GroundnutCouncil Symposium.

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Groundnut Virus Research at ICRISAT

A. M. Ghanekar*

Several virus diseases of groundnut have beenreported in India based on symptoms, hostrange and biological properties. These proper-ties are now regarded as inadequate to identifya virus. Characterization should be based onserology, electron microscopy, transmissionand physico-chemical properties.

Three economically important virus diseases(bud necrosis, clump and peanut mottle) andseveral virus diseases of minor importance inIndia have now been fully characterized.

Bud Necrosis Disease

Bud necrosis disease caused by tomato spottedwilt virus (TSWV) has been recognized as oneof the most important virus diseases ofgroundnuts in India (Chohan 1974; Ghanekar etal. 1979). The disease has also been reported ongroundnuts in several other countries includingBrazil, USA, S. Africa and Australia (Costa 1941;Halliwell and Philley 1974; Klesser 1966; Helmset al. 1961). A clear account of the diseasesymptoms was given by Reddy et al. (1968).

The causal virus was characterized at ICRISAT(Ghanekar et al. 1979) and the thrips vectorchiefly responsible for transmitting the diseasewas identified (Amin et al. 1978). Bud necrosishas been shown to cause yield losses of up to50% and occurs in all the major groundnutgrowing areas of India. The incidence rangesfrom 5 to 80% in different parts of the country(Chohan 1972; Ghanekar et al. 1979).

S y m p t o m s on Groundnu t

The typical disease symptoms on groundnutinclude chlorotic rings, terminal bud necrosis,severe stunting, proliferation of axillary shoots

* Plant Pathologist, Groundnut Improvement Prog-ram, ICRISAT.

with deformed leaves and production of dis-colored and shrivelled kernels.

Diagnostic Hosts

The virus produces chlorotic and necrotic locallesions on Vigna unguiculata (cowpea cv C-152)and necrotic local lesions onPetuniahybrida (cvCoral Satin) which do not become systemic.

Host Range

The virus was found to have extremely widenatural and experimental host ranges. Vigna radiata (cv Hy-45), Vigna mungo (cv UPU-1),Phaseolus vulgaris (cv Local), Vicia faba, Lycopersicon esculentum (cv Pusa Ruby) andPisum sativum were all susceptible to infectionby TSWV. In addition a number of weedscommonly encountered in groundnut fieldswere also susceptible.

Biological PropertiesThe virus has a thermal inactivation point at46°C and the longevity in vitro is approximately5 hours at 25°C. These properties indicated thatbud necrosis could be related to tomato spottedwilt virus.

Electron Microscopy

Thin sections of groundnut leaves under theelectron microscope showed membrane boundvirus particles 70-90 nm in diameter and wereassociated with the endoplasmic reticulum.These particles resemble those of TSWV.

Serology

Antisera for TSWV obtained from the USA andS. Africa when used in haemagglutination testsclearly revealed the presence of viral antigens incrude bud necrosis infected groundnut extracts.

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Transmiss ion

The virus was mechanically sap transmissiblefrom plant extracts prepared in 0.05M potas-sium phosphate buffer (pH 7.0) containing0.02M 2-mercaptoethanol added as an an-tioxidant. It was consistently transmitted byFrankliniella schultzei (Trybom) and to a lesserextent by Scirtothrips dorsalis Hood. Thevirus was not transmissible through seed ofgroundnut (Ghanekar et al. 1979).

C o n t r o l

Experiments on effects of date of sowing, plantspacing and intercropping with pearl millet ondisease incidence are giving promising results.Early planting at the onset of the rainy seasondecreased disease incidence and reducedlosses from bud necrosis disease. Planting athigh density also reduced disease incidence(Table 1).

Experiments on the effect of intercroppingwith pearl millet were started recently andpreliminary observations show a lower diseaseincidence in the intercropped situation whencompared with the sole crop.

Screening for Disease Resistance

So far nearly 7000 germplasm lines of Arachis hypogaea have been screened under highnatural disease incidence in the field and noneshowed any marked resistance to the virus.However, the cultivars Robut 33-1 and NC Acc2575 consistently showed lower than averageincidence of the disease under field conditions.

Several wild Arachis species have beenscreened under high natural disease incidencein the field, and also by mechanical sap inocu-lation in the screenhouse. So far Arachis chacoense, A. glabrata, Arachis sp (PI 262848)and Arachis pusilla have not become infected inthesetests, butthese results need confirmation.

Cultural Practices

As sources of resistance are still being sought,efforts are being concentrated on the develop-ment of cultural practices to control the disease.

Peanut (Groundnut)Clump Virus

A disease of groundnuts resulting in severelystunted plants with small, dark green leaveswas observed in 1977 in crops grown in thesandy soils of Punjab and Gujarat. Most of theinfected plantsfailed to produce pods, and evenin cases of late infection, losses of up to60% were recorded. A sap transmissiblevirus which reproduced the disease symptomswas isolated and is being characterized.

Symptoms on Groundnut

Infected plants are severely stunted with smalldark green leaves. The young quadrifoliateleaves show mosaic mottling and chloroticrings. Roots become dark colored and theouter layers peel off easily.

Table 1. Effect of plant spacing on the incidence of bud necro sis disease (TSWV).

Postrainy season Postrainy seasonInterrow andIntrarow plant

1978--79 1979--80Interrow andIntrarow plantspacing Disease Yield Disease Yield(cm) (%) (kg/ha) (%) (kg/ha)

37.5 x 5.0 10 3493 7 215337.5 x 15.0 23 2855 16 152475.0 x 5.0 20 2289 9 157075.0 x 15.0 40 1745 18 917

150.0 x 5.0 23 1270 11 740150.0 x 15.0 43 777 21 409

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Diagnost ic Hosts

Phaseolus vulgaris (cv Local), on which thevirus produces veinal necrosis, and Canavalia ensiformis, on which discrete necrotic lesionswith chlorotic centers are produced, have beenidentified as diagnostic hosts.

Host Range

The virus has an extremely wide host rangeand several weeds commonly occurring ingroundnut fields are also infected by the virus.

Biological Propert ies

The thermal inactivation point of the virus isbetween 60° and 65°C and longevity in vitro is2-3 days at room temperature.

Pur i f icat ion

Nicotiana hybrid (N. clevelandii x N. glutinosa) consistently gives high virus concentrations. A method to purify the virus from crude Nicotiana hybrid leaf extracts has been successfully de-vised. Polyethylene glycol precipitates ofchloroform treated infected leaf extracts aresubjected to density gradient centrifugation insucrose solutions. Virus obtained from thegradients can be inoculated onto healthygroundnut plants and diagnostic hosts where itproduces typical symptoms.

Electron Microscopy

Purified virus preparations, and leaf dips ofinfected leaves of groundnut and Nicotiana hybrid, revealed the presence of rod-shapedvirus particles of 200-500 nm in length, and23-25 nm in width, with a central hollow core.

Sero logy

Antisera were obtained of strains of the soil-borne tobacco rattle and pea early browingviruses which have particle morphology similarto the clump virus. These were tested againstcrude plant extracts and purified extracts ofclump virus but there was no positive reaction.

Transmission

The virus was successfully transmitted by

means of mechanical inoculations and grafting.The following observations suggested that

the virus was soilborne and possibly transmit-ted by nematodes: (1) the disease was re-stricted to sandy soils; (2) infected plants couldbe obtained by sowing healthy seeds in soilsamples collected from depths of 12-28 cm ininfected fields; (3) the disease occurred inpatches in the field and reappeared in the samepositions in succeeding years; (4) air-driedsoil could not reproduce the disease; and(5) nematocide applications to infested soils re-duced the incidence and spread of the disease.

Nematodes isolated from infested soils, andinoculated onto healthy plants grown insterilized soil produced the disease in somerecent tests. These results need to beconfirmed.

Relat ionship w i t h Simi lar VirusesRepor ted on Groundnuts

Based only on symptoms, Sundararaman(1927) described a similar disease in India,which he named clump.

The symptoms observed also resemble thoseof clump disease reported from West Africa(Germani et al. 1975). In both cases the diseasewas soilborne and application of Nemagonreduced the disease (Germani et al. 1973).Both diseases are caused by viruses withsimilar particle structure (Germani et al. 1975;Thouvenel et al. 1976). However, both viruseshave to be tested serologically before the rela-tionship between them can be confirmed.

Contro l

Nematocide and Fungicide Treatments

In collaboration with the Oilseeds Sectionof Punjab Agricultural University, the nema-tocides Nemagon, Carbofuran, Temik anda mixture of the fungicides Bavistin and Blitox,were tested for their effect in controlling thedisease. Untreated plots served as controls. Thechemicals were applied to the soil 1 weekbefore planting and the susceptible cultivarM-13 was used. Nemagon and Temik were themost effective in reducing the disease incidenceand increasing the yield when compared withuntreated plots.

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Screening fo r Disease Resistance Biological Proper t ies

Screening was carried out in infected soilsof the Punjab where the disease had beenrecurring for three consecutive years. Theplots selected had shown up to 98% incidenceof the disease in the previous season. A sus-ceptible cultivar M-13 was sown after every 10test cultivars. Eight cultivars (M 884-75, C 334-AB-13, NC Acc 17847, NC Acc 17866, NC Acc17732, NC Acc 17740, NC Acc 17840, and EC21887) showed no disease symptoms.

Another ten cultivars showed a very lowincidence of visibly diseased plants. These cul-tivars will be retested under field and labora-tory conditions before any conclusions on theirpossible resistance or tolerance can be drawn.

Peanut (Groundnut)Mottle Virus

Peanut mottle virus (PMV) is widespread andhas been positively identified in the USA (Kuhn1965), E. Africa (Bock 1973), Australia(Behncken 1970), Europe (Schmidt et al. 1966),Japan (Inouye 1969), the Philippines (Benignoet al. 1977), South America (Herold et al. 1969),West Malaysia (Geh et al. 1973) and India(Reddy et al. 1978). The disease also appears tobe present in China (Gibbons, personal com-munication). The disease can cause up to 30%loss in yield (Kuhn et al. 1975).

S y m p t o m s on Groundnu t

Newly formed leaves show mild mottling andvein clearing, whereas older leaves show up-ward curling and interveinal depression withoccasional dark green islands. Infected plantsare not severely stunted and older plants sel-dom show typical disease symptoms.

Diagnost ic Host

The virus produces reddish brown necroticlesions on inoculated leaves of Phaseolus vul-garis (cv Topcrop) which was found to be a good diagnostic host for the virus.

Host RangeThe virus has a narrow host range and infectsmostly legumes.

The virus has a thermal inactivation point be-tween 55° and 60°C and longevity in vitro is 48hours at 25°C.

Pur i f icat ion and An t i se rumProduc t ion

The virus has been successfully purifiedemploying a method developed at ICRISAT(lizuka et al. in preparation). An antiserum hasbeen produced by injecting purified virus pre-parations into rabbits.

Electron Mic roscopy

Purified virus preparations and sections of in-fected leaves, when observed under the elec-tron microscope, reveal the presence of long,flexuous, rod-shaped particles of 700 nm inlength.

Serology

An antiserum obtained from the USA, and oneproduced at ICRISAT, were reacted with PMVusing agar gel diffusion, haemagglutinationand Enzyme Linked Immuno Sorbant Assay(ELISA) tests. Positive results were obtained inall tests for PMV.

Transmiss ion

The virus is seed transmitted in a rangefrom 0.1 to 3.5% depending on the groundnutcultivars.

Aphis craccivora and Myzus persicae trans-mit the virus in a stylet-borne (non-persistent)manner.

Contro l

Screening for Disease Resistance

The natural incidence of PMV is not highenough for meaningful screening of cultivarsfor resistance in the field. It was thereforenecessary to reproduce the disease on a largescale underfield conditions. A spray inoculationtechnique has been developed in which in-oculum is mixed with celite and sprayedthrough fine nozzles at 50 PSI. About 1000

214

plants can be inoculated in one hour and about80% of the plants become infected.

An earlier report indicated that no immunityhad been found to peanut mottle virus (Kuhn1968) in groundnut cultivars from differentparts of the world. However, tolerance of somecultivars to PMV where there is no reduction inyield even though plants became infected, wasreported (Kuhn et al. 1978). Using the inocula-tion technique described, about 200 cultivarshave been screened sofarand yield losses havebeen estimated. None of the cultivars testedshowed immunity or tolerance to PMV.

Screening Cultivarswhich do not Transmitthe Virus Through the Seed

Diseased plants with infected seeds are theprimary sources of inoculum. The secondaryspread is by aphids which acquire the virusfrom plants infected through seeds. It would bedesirable to have a cultivar which did nottransmit the virus through the seed. Approxi-mately 1000 seeds were obtained from infectedplants of a range of cultivars. So far two cul-tivars, EC 76446 (292) and PI 259747, have notshown any seed transmission. Over 5000 seedsfrom infected plants of these cultivars will soonbe tested under field conditions.

Virus Diseasesof Minor Importance

Cowpea mild mottle virus (CMMV) and peanutgreen mosaic virus (PGMV) have been charac-terized on the basis of electron microscopy,serology, chemical characteristics and hostrange. CMMV has been detected occurringnaturally in the Punjab, Andhra Pradesh andUttar Pradesh but the incidence is less than1%. PGMV has so far been detected only in theChittoor district of Andhra Pradesh.

ReferencesAMIN, P. W., REDDY, D. V. R., and GHANEKAR, A. M. 1978.

Transmission of bud necrosis virus (BNV) ofgroundnut by chilli thrips, Scirtothrips dorsalis (Thysanoptera, Thrlpidae). Indian Phytopathology31: 118 (Abstract).

BEHNCKEN, G. M. 1970. The occurrence of peanutmottle virus in Queensland. Australian Journal ofAgricultural Research 21: 465-472.

BENIGNO, D. A, and FAVALI-HEDAYAT, M. A. 1977.Investigation on previously unreported or notewor-thy plant viruses and virus diseases in Philippines.Food and Agriculture Organization Plant ProtectionBulletin 25: 78-84.

BOCK, K. R. 1973. Peanut mottle virus in East Africa.Annals of Applied Biology 74: 171-179.

CHOHAN, J. S. 1972. Final Progress Report. ICARscheme for research on important diseases ofgroundnut in the Punjab for the period 1957-1967.Department of Plant Pathology, Punjab AgriculturalUniversity, Ludhiana, India, 117 pp.

CHOHAN, J. S. 1974. Recent advances in diseases ofgroundnut in India. Pages 171-184 in CurrentTrends in Plant Pathology. (Eds. S. P. Raychauduriand J. P. Verma). Lucknow University, India.

COSTA, A. S. 1941. Una molestia de virus do amen-doim {Arachis hypogaea L). A mancha anular.Biologico 7: 249-251.

GEH, S. L., and TING, W. P. 1973. Loss in yield ofgroundnuts affected by groundnut mosaic vimsdisease. Malaysian Agriculture Research Develop-ment Institute Research Bulletin 1: 22-28.

GERMANI, G., and DHERY, M. 1973. Observations et ex-perimentations concernant le role des nematodesdans deux affections de I'Arachide en Haute Volta:la "chlorose" et le "clump". Oleagineux 28: 235-242.

GERMANI, G„ THOUVENEL, J. C, and DHERY, M. 1975. LerabougrissementdeI'Arachide: Unemaladieavirusau Senegal et en Haute-Volta. Oleagineux30: 259-266.

GHANEKAR, A. M., REDDY, D. V. R., IIZUKA, N., AMIN, P. W.,and GIBBONS, R. W. 1979. Bud necrosis of groundnut[Arachis hypogaea L.) in India caused by tomatospotted wilt virus. Annals of Applied Biology93: 173-179.

HALLIWELL, R. S., and PHILLEY, G. 1974. Spotted wilt ofpeanut in Texas. Plant Disease Reporter 58: 23-25.

HELMS, K., GRYLLS, N. E., and PURSS, G. S. 1961. Peanutplants in Queensland infected with tomato spottedwilt virus. Australian Journal of Agricultural Re-search 12: 239-246.

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HEBOID, F., and MUNZ, K. 1969. Peanut mottle virus.Phytopathology 59: 663-666.

IIZUKA, N., RAJESHWARI, R., and REDDY, 0. V. R. Purifica-tion and chemical characterization of peanut mottlevirus (in preparation).

INOUYE, T. 1969. Peanut mottle virus from peanut andpea. Nogaku Kenkyu 52: 159-164.

K LESSER, P. J. 1966. Tomato spotted wilt virus onArachis hypogaea. South African Jou rnal of Ag ricu I-ture Science 9:731-736.

KUHN, C. W. 1965. Symptomatology, host range andeffect on yield of a seed transmitted peanut virus.Phytopathology 55: 880-884.

KUHN, C. W., and DEMSKI, J. W. 1975. The relationshipof peanut mottle virus to peanut production. Re-search Report. Agriculture Experiment Stations,University of Georgia, USA.

KUHN, C. W., SOWELL, G. Jr., CHAKLEY, J. H., andSTUBBS, H. F. 1968. Screening for immunity topeanut mottle virus. Plant Disease Reporter56: 467-468.

KUHN, C. W., PAGUIO, O. R., and ADAMS, D. B. 1978.

Tolerance in peanuts to peanut mottle virus. PlantDisease Reporter 62: 365-368.

NABIANI, T. K., and DHINGRA, K. L. 1963. A mosaicdisease of groundnut (Arachis hypogaea L). IndianJournal of Agricultural Science 33: 25-27.

REDDY, M., REDDY, D. V. R., and APPA RAO, A. 1968. A new record of virus disease on peanut. Plant DiseaseReporter 52: 494-495.

REDDY, D. V. R., IIZUKA, N., GHANEKAB, A. M., MUBTHY,V. K., KUHN, C. W., GIBBONS, R. W., and CHOHAN, J. S.1978. The occurrence of peanut mottle virus in India.Plant Disease Reporter 62: 978-982.

SCHMIDT, H. B., and SCHMELZEB, K. 1966. Elektronen-mikroskopische Darstellung and vermessung einessaftubertragbar virus aus der Erdnuss (Arachis hypogaea L). Phytopathologische Zeltschrift55: 92-96.

SUNDABA RAMAN, 1926. A clump disease ofgroundnuts. Madras Agricultural Department YearBook 1926: 13-14.

THOUVENEL, J. C, DOLLET, M„ and FAUQUET, C. 1976.Some properties of peanut clump, a newly disco-vered virus. Annals of Applied Biology 84: 311-320.

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Session 7 — Groundnut Pathology

Discussion

B. S. GillRust was first reported from the Punjab inIndia and now its incidence is increasing veryfast in many parts of the country, but atpresent there is no rust in the Punjab. Has Dr.Subrahmanyam any explanation for this?

P. SubrahmanyamIt is difficult to explain, but rust was firstreported from the greenhouse in the Punjaband not the field. Moreover, in Punjabgroundnut is a rainfed crop taken once in a year, whereas in other parts of Indiagroundnuts are grown throughout the year.Therefore, the conditions in the Punjab maynot be conducive to rust development.

J. S. ChohanJ. S. Chohan supported the report and elabo-rated that the infestation has correlation withtemperatures that are very high in Punjab andHaryana and not conducive to the develop-ment of the pathogen.

S. M. MisariHow soon do the detached leaves form rootsand become established? How long do thesedetached leaves last in this system? Is theresistance of detached leaves reduced? Haveyou noticed any nodulation on the rootsformed from detached leaves?

D. J. Nevill(1) The rooted leaves can remain in good

condition for 2 to 3 months.(2) No nodulation was observed in the roots

in the sterile sand.(3) No reduction in disease resistance was

observed; there was a good correlationbetween disease rating in the laboratoryand in the field.

(4) Roots begin to form after 10 to 14 days ofincubation.

M. V. R. Prasad(1) Do you think that it is equally important to

identify the varieties that yield well despitethe incidence of leaf spot or rust diseases?Has any work been done in this direction?

(2) I understand that some of the varieties ofgroundnut observed to be resistant atHyderabad do not maintain the same de-gree of resistance at Dharwar. Do youthink that the collection of rust materialfrom Dharwar area would enable us toidentify some physiological races, aboutwhich data are scant at present?

P. Subrahmanyam(1)1 agree. Work is in progress along these

lines, and the subject was covered by Dr.Nigam yesterday. We now have foliardisease resistant lines that outyield na-tionally released susceptible cultivarsunder unprotected conditions but, in mostcases, they are outyielded by the suscepti-ble cultivars when grown under a protec-tive fungicide regime.

(2) I agree that we need to study the reactionsof the resistant lines at Dharwar as well asin many other locations. Such trials arebeing carried out and should give goodindications of whether physiological racesexist.

C. HarknessIs there any relation between dry seed resis-tance to A flavus and seedling resistance to A flavus crown rot?

J. S. ChohanThere does not appear to be any such relation-ship and they appear to be independent ofeach other.

P. Subrahmanyam, V. K. MehanAflaroot disease may originate from eitherseedborne or soilborne inoculum. Resistanceto invasion of pods or of seeds by A flavus could reduce seedborne inoculum but wouldnot affect soilborne inoculum.

We have found that some cultivars with good

217

dry seed resistance to A. flavus colonizationalso possess measurable resistance to aflarootand crown rot, J-11 being an example, butthere is no evidence of a direct connectionbetween the two kinds of resistance.

A. S. ChahalWhat about the dangers of the seedbornenature of Cylindrocladium in groundnuts?

M. K. BeuteIn Virginia, Dr. Porter suggested the possibilitythat the pathogen could be seedborne. Seedfrom infected plants is small and usually willnot germinate. In commercial supplies ofseeds, such small seeds are rejected. Thus I think that thefungus is not spreading throughseeds in the USA and it is not I ikely to spread toIndia through seeds.

M. A. Ali(1) Was the fungicide for Sclerotinia applied

to the soil or foliage?(2) How does the foliage-applied fungicide

control the soilborne pathogen's effect onroots, because the fungal invasion getsreplenished from the soil every time it isaffected by the chemical?

(3) Why is the use of preemergence herbicidefound to be less effective than post-emergence applied herbicide?

(4) How many times did you have to usebenomyl as a soil dressing to controlSclerotinia blight (to Dr. Smith)?

D. M. PorterThe fungicide was applied as a foliage spray.Foliage systemic fungicides can be washeddown to the soil and absorbed into the plantand protect the stem tissues from the patho-gen. They are very active. The pathogen can-not be eradicated in this way from the soil, butthe systemic fungicide will protect the plant.

Preemergence herbicides were not effectivebecause they do not have a long-term effect.

D. H. SmithI used benomyl only in a greenhouse experi-ment. In practice, benomyl is not used as a soilfungicide. It was demonstrated that the fungi-cide moves upward in the plant if applied tothe soil. However, the foliar application did not

show any downward movement in the plant.The manufacturer did not feel soil applicationto be practical in a field situation.

I. S. SekhonIn the ICRISAT 9-pointfield scale, when defoli-ation is above 50% a cultivar has to be scored9. For example, there is a lot of differencebetween the susceptibility of the two varietiesM-13and Faizpur 1-5. But with this scale, bothof these varieties had to be scored 9 at least atthe time of second scoring?

P. SubrahmanyamDefoliation is only one among the dif-ferent parameters accounted for in the 9-pointscale. It needsto be taken into account with theother parameters.

D. J. NevillDefoliation is a difficult parameter to measureand this is to be considered with other factorssuch as the season length of the variety. In a short-season cultivar, there will be more de-foliation, whereas in a long-season cultivarless defoliation occurs at the same time ofscoring.

P. SubrahmanyamThe cultivars mentioned are of differentmaturity groups. Physiological maturity mustbe considered.

J. S. SainiIn one of the slides you have shown that withthe fungicidal control of leaf spots the yieldincrease has been of the order of 230% overcontrol. What fungicide was used, at whatdosage, and what number of sprays weregiven?

P. SubrahmanyamWe gave seven sprays of Daconil at the re-commended rates at 2-week intervals startingat the initiation of disease development.

P. S. ReddyIt has been reported that the cultivar Robut33-1 is tolerant to the bud necrosis virus. Thesame cultivar has been reported to be highlysusceptible to thrips, the vector of this disease.Is there any explanation for this peculiar be-

218

havior of this cultivar, i.e., it is susceptible tothe vector but resistant to the disease?

P. W. AminRobut 33-1 is susceptible to the virus if it issap-inoculated. Thrips injure the leaves butvirus transmission or multiplication may notbe efficient. This is based on our field observa-tions only. We have now initiated laboratorystudies to confirm these observations.

V. RagunathanTo control the soilborne inoculum ofSclerotinia, is there any method other thanchemical control available that can be prac-ticed by the SAT farmers? For example, or-ganic amendments or calcium enrichment ofthe soil, etc.?

D. M. PorterWe have looked at different cultural practiceslike (1) different seed rates, (2) different til-lage practices, (3) planting methods (such asturn rows), (4) spacing between the rows etc.,but we believe that none of these methods iseffective in controlling Sclerotinia. We havenot tried calcium, but we feel that the mostpromise lies in the identification of resistantvarieties.

V. RagunathanCan green manure or any soil amendmentcontrol the disease — perhaps calcium?

D. H. SmithRow orientation has been tried recently tostudy the effect of the sun and the wind ondisease development.

D. R. C. BakhetiaIntercropping of pearl millet in groundnutdecreased the movement of the thrips vector.Did it result in any difference in the diseaseincidence transmitted by the thrips?

A. M. GhanekarThis experiment is still in the field and we donot yet have complete data. However, early inthe season disease incidence was 20 to 25% inthe sole crop but only about 15% in theintercrop situation.

R. W. GibbonsWould K. Middleton care to comment on themanagement of TSWV in Australia, particu-larly on the cultural practices that have helpedto reduce the disease in recent years?

K. MiddletonYes. TSWV is present in Queensland but doesnot produce the bud necrosis symptoms. Wecontrol this virus by management practices,particularly by controlling the alternate weedhosts. But the disease incidence can increasewith climatic conditions and under poor man-agement. Weed control is important. Thereare a large number of alternate hosts. Therehas been as much as 70 to 80% diseaseinfection, but only in seasons with high weedpopulations.

C. Raja Reddy(1) Does the screening technique take into

account very high vector pressure andBNV pressure, as the drawback of thecommon field screening technique quotedin literature is that it does not differentiatebetween resistance to vector and resis-tance to the virus.

(2) Variation has been shown to the vector — two biotypes in respect of BNV. Is thereany strain variation in BNV?

D. V. R. ReddyRobut 33-1 and NC Acc 2757 were tested underhigh disease pressure. Perhaps Dr. Amin cantell us about the vector pressure.

P. W. AminThe susceptible cultivar TMV-2 showed 70 to80% disease while Robut 33-1 showed 20 to50% disease under similar high vector pres-sure.

D. V. R. ReddyWe have examined virus isolates from differ-ent places but did not detect any variation.

M. P. Ghewande(1) What was the percentage incidence level

of BNV under 37.5 x 5 cm and 150 x 15cm spacings?

(2) If it is the case that closer planting reducedthe incidence of BNV, what could be thereason?

219

(3) In India, row-to-row spacing normallyadopted is 30 cm or 45 cm, except in theSaurashtra area of Gujarat where it is 90cm. Why did you try such a wide spacingas 150 cm?

A. M. Ghanekar(1) For the cultivar TMV-2 in the 1979 rainy

season, the closest plant spacing (37.5cm x 5 cm) resulted in 48.7% bud necrosisinfected plants while the wider spacing(150 cm x 15 cm) gave 94.0% diseasedplants.

(2) Closer planting reduced the percentageincidence but not the actual numbers ofplants infected on a unit area basis.

R. W. GibbonsRecommendations are always for narrowerrow spacings but how often are they followedby the farmers? The same recommendationswere madef or rosette control. It is the result ofpoor extension of research; that needs to beimproved. Most farmers do not follow exten-sion work recommendations.

S. H. PatilThe management recommendation to sowearly for reducing the incidence of bud ne-

crosis in the rainy season is not practical. In thisseason, sowing can be done only after therains have started. Similarly the rabi (post-rainy season) sowing in October is notpracticable in India as the fields will not beready for sowing. You are aware that the rabigroundnut occupies mostly the paddy fallows.Your observations may be of scientific valuebut not practicable.

D. V. R. ReddyEarly planting in the rainy season means assoon as sufficient rain has fallen. Very oftenthe farmer does not do this.

S. H. PatilIn Maharashtra, delayed plantings in Januaryreduced the disease incidence; we got 30% inDecember planting and 10% in January plant-ings.

P. W. AminThe disease incidence depends on the migra-tion of the thrips rather than early or lateplantings. Our results are from AndhraPradesh, and the thrips invasion may varyfrom area to area. There is a need to do moretrials over more varied ecological zones.

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Session 8

Country ReportsChairman: R. W. Gibbons Rapporteurs: A. M. GhanekarCo-Chairman: J. P. Moss P. T. C. Nambiar

S. N. Nigam

Groundnut Production, Utilization, ResearchProblems and Further Research Needs

in Australia

K. J. Middleton*

Production

Commercial groundnut production in Australiais centered in two distinct areas in the state ofQueensland. Total planting in recent years hasbeen 32 000-36 000 ha with production rangingfrom 32 000 to 62 000 tonnes. There is no govern-ment control over the area planted. An erect,large-seeded Virginia type, known as VirginiaBunch, is planted on 75-80% of this area, andSpanish types are sown on the balance. TwoSpanish types are grown— a red-seeded cul-tivar of uncertain origin, and a pink-seeded typewhich has been introduced recently to theindustry. Approximately two thirds of the cropis grown in the traditional groundnut areas ofsouthern Queensland, while the balance isgrown on the Atherton Tableland and adjacentareas in northern Queensland, a region of rapidexpansion.

In Australia, groundnut production is highlymechanized, and heavily capitalized. Sig-nificant amounts of new technology have beenobtained from successful groundnut producingcountries, particularly the USA. In someinstances this technology has not been directlyapplicable, and some modification has beennecessary. This has been particularly noticeablewith harvesting procedures, largely because ofthe peculiarities of soil types used, and due tothe centralized marketing establishment.

Utilization

Groundnut production in Australia is intendedfor the edible market, either as savory or con-

* Plant Pathologist, Department of Primary Indus-tries, J. Bjelke-Petersen Research Station, Kin-garoy, Queensland.

fectionery items, as peanut butter, or as in-gredients in baked biscuits (cookies), etc. Pro-duction of oil is incidental to the production ofedible kernels. Consumption on the domesticmarket is slightly less than 30 000 tonnes ofedible kernels. Per capita consumption is low,relative to consumption in many other pro-ducing countries. Any surplus over local demandis available for export, and substantial sales toNew Zealand, Hong Kong, Japan, Korea and theUnited Kingdom have been made in recentyears.

Research Problems

The state-wide average yield of groundnut isalso low — approximately 1250 kg/ha; howeverthere are cases of yields exceeding 6000 kg/ha.These low yields, coupled with rising costs ofproduction (notably machinery fuel and pes-ticides) create the major difficulty in com-mercial production. Innovative research break-throughs that will improve yields and reducethe cost of production are urgently needed inthe peanut industry.

Low average yields, with occasional highyields, are explained by limitations in the avail-ability of water to the crop. Practically allAustralian groundnuts are grown without thebenefit of irrigation because significantamounts of suitable water are not available.Average rainfall during the growing season inthe southern growing area is 500 mm; variabili-ty is high. In the northern area, 1300 mm isnormal during the growing season, and thisexplains the recent increase in production inthis area. The cultivars grown exhibit droughttolerance, and this trait must be retained in anycultivar used in the future.

The soils used for most of Australia'sgroundnut production are friable clays. They

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have better moisture holding capacity than thesandy soils commonly used for the crop. How-ever, crop yields appear to be insensitive toinputs of technology such as introduced cul-tivars, nutritional improvement, disease controland tillage innovations, so that the improvedyields experienced in some other countrieshave not occurred in Australia. The occasionalhigh yields referred to above are usually fromcrops grown on land being returned to cultiva-tion after a period under pasture. This wouldsuggest that the physical state of the soil islimiting production, and together with thelimited amount of rainfall, is a factor affectingthe supply of available moisture to the peanutplants. Also, there are indications that aninteraction exists between soil physical condi-tions and nutrition, soilborne disease, andharvesting losses. It has been determined thatsymbiotic nitrogen fixation by the crop isadequate. The complex of soil physical condi-tions, moisture, nutrition and disease is thesubject of a research program commencingwithin a few weeks, based at the J. Bjelke-Petersen Field Station, at Kingaroy.

Diseases also limit yields and/or increasecosts of production. A serious problem undoubt-edly associated with drought conditions is theoccurrence of aflatoxins in the harvestedcommodity. Maximum efforts to reduce post-harvest development of aflatoxins have high-lighted the importance of preharvest contami-nation by alfatoxins in seasons when theproblem assumes real significance. As such,irrigation or other drought mitigation proce-dures are not available. It appears that the mosteffective way to control aflatoxin contaminationis by host resistance. A pathologist is currentlyworking to demonstrate the degree of associ-ation of aflatoxin accumulation with biotic,climatic, and cultural conditions. Quantificationof the importance of these factors will enable a reasonable prediction to be made of the likeli-hood of serious aflatoxin contamination.

Seedling diseases, especially crown rot andpreemergence rot, have been adequately con-trolled since the introduction of captan-quintozeneseed treatment. However, proposedutilization of aflatoxin contaminated material asseed coupled with some expansion of thegroundnut crop onto sandy soil under irri-gation, has demonstrated a possible inadequacyof captan-quintozene dust treatment to control

seed-borne Aspergillus flavus. The recent de-velopment of a waterless flowable formulationof organic fungicides will be tested as seedtreatments for control of this problem.

The stem, peg and pod rot caused by the soil-inhabiting fungus Sclerotium rolfsii is a majorcause of reduced yields. This disease can causelosses of 25% or more, and attempts to controlthe disease with chemical treatments or culturalpractices (e.g., deep turning) have been unsuc-cessful. There is a suggestion that the disease isworse when soil conditions are conducive tomoisture stress and low yields. The influence ofthose soil conditions, which produce poor plantgrowth and production, onS. rolfsii occurrenceand severity may provide a clue to control ofthis disease, possibly by biological means.

Another cause of yield loss and increasedcost of disease control is the group of foliagediseases caused by Cercospora arachidicola, Cercosporidium personatum and Puccinia arachidis, the early and late leaf spots andrust, respectively. The leaf spot diseases havebeen known for many years, but rust was notknown in Australia until 1973 when it was foundin north Queensland. It spread south in 1976,and is now present in all areas each year. Thesethree diseases are controlled by protectantfungicides, but the cost of such control is high,particularly where benomyl-tolerant strains ofthe late leaf spot pathogen occur. Currently,control measures are aimed at optimizing dis-ease control with minimum cost, includingreducing the number of applications wherepossible and improving the efficiency of fun-gicide applications. The breeding programincludes screening germplasm for rust resis-tance, and will include leaf spot resistance whenpracticable..

Net (web) blotch, Sclerotinia blight, Cylin-drocladium black rot and Diplodia blight arerelatively minor diseases, but in isolated casescause serious losses. Net blotch can be control-led by some fungicides but the relationshipbetween environment and infection needsto bemore closely studied to enable growers toadjust applications accordingly. This relation-ship is being investigated. Chemical control ofSclerotinia blight appears possible, but the costof the practice is not yet known. The effect of soilphysical conditions on the ecology of Diplodia and Sclerotinia should be studied to gain anunderstanding of disease development and to

224

enable effective control measures to be found.To date, nematodes have not been a consis-

tent problem in traditional peanut soils, butextension of the industry into lighter soiltypes may cause problems. Virus diseaseshave caused little commercial loss to date. Thestrain of peanut mottle virus present through-out the peanut area causes only a slight loss inexisting cultivars. Tomato spotted wilt virusseriously affects yields, but adequate weedcontrol provides sufficient protection byminimizing the number of plants infected.

In summary, low yields and high costs ofproduction are features of the Australiangroundnut industry, and are consequences oftwo factors: (1) the unreliability of rainfall inmuch of Queensland and (2) the high cost ofcontrol of crop pests, particularly diseases andweeds.

Future Research Needs

The unreliability of rainfall has forced growersto use a specific soil type, sufficiently friable toallow harvesting, but at the same time provid-ing a degree of drought insurance. The soil typeused has resulted in a need for nutritionalresearch, including investigations of Rhizobium spp. The soil type being used appears to havedeveloped one or more physical conditionswhich contribute to low yields, to increased

disease development, and to soil erosion. Thesoil type, and its erosion potential, have stimu-lated studies of tillage methods. This researchinvolves the development of machinery suit-able for production practices without destroy-ing preceding crop residues.

A plant breeding program is also under way toimprove yields, as well as to control diseases,while maintaining drought tolerance and mar-ket competitiveness. This will produce newcultivars, some of which might be a differentbotanical type to those currently being used. Itmight be necessary, therefore, to adopt newmachinery capable of handling such cultivars.New machinery inputs will continue as im-proved pest control using more effectivemethods of pesticide application are de-veloped. In addition to the control of diseasesby breeding for resistance, supplemental dis-ease and weed control measures will continueto be necessary. Insects are not a problem. Anintegration of agronomy, breeding, soil conser-vation, engineering and pathology is needed tofind answers that will improve yields andminimize production costs. A multidisciplineresearch team has been formed within theDepartment of Primary Industries at Kingaroy,and in North Queensland. The potential ofgroundnut oil as an alternative fuel for com-pression ignition engines might provide theincentive needed to carry this research throughto a successful end.

225

Groundnut Production, Utilization, ResearchProblems and Further Research Needs

in Bangladesh

M. A. Hamid*

Bangladesh is predominantly an agriculturalcountry and 85% of the population depends onagriculture. There is a need to become self-sufficient in food and to produce sufficientquantities to support agro-based industries,and also to earn foreign exchange.

A recent report (Rahman et al. 1976) indicatedthat an adult in Bangladesh requires 53 g ofprotein/day but at present the per day consump-tion of a man is only 8 g. The annual edible oilrequirement at the present supply rate of 1.1kg/capita per annum is 82 500 metric tons. If thereasonable rate is fixed at 2.2 kg/capita perannum, the annual requirement then becomes165 000 metric tons, but at present Bangladeshis producing only 54 910 metric tons, mainlyfrom mustard and groundnut. This huge deficitis being met either by importing oil or oilseedsfrom abroad and thereby using hard-earnedforeign exchange.

Production

Bangladesh produces eight types of oilseeds ofwhich mustard, rapeseed, sesame andgroundnut are the principal ones. The acreage,production and yield of groundnuts are shownin Table 1. Groundnut produces more thantwice theyield of sesame and mustard (Table 2).

Groundnut can be grown throughout theyear. Land preparation requirement forgroundnut is more or less equal in highlandcompared with mustard and rapeseed, but in"charlands", (very sandy or sandy loam soils),land preparation is less. Groundnut is not influ-enced very much by environmental variations.The nitrogenous fertilizer requirement is not

* Scientific Officer, Institute of Nuclear Agriculture,P.O. Box 4, Mymensingh, Bangladesh.

Table 1. Groundnut area, production, andyield/acre In Bangladesh.

Year Area (acres) Production Yield/acre

1969-70 80 51 17.51970-71 78 46 16.21971-72 66 36 15.01972-73 57 31 14.91973-74 51 28 15.11974-75 48 26 14.91975-76 55 31 15.51976-77 52 23 12.11977-78 58 27 12.8

Source: Bangladesh Bureau of Statistics 1979 (Ministry ofAgriculture).

Note: Area In thousand acres; production Jn 1000 long tons;yield/acre = maunds/acre; one ton = 27.438 maunds;one maund - 82 lbs -37.25 kg.

great mainly because symbiotic bacteria livingin their roots fix atmospheric nitrogen.

The most important point in favor ofgroundnut cultivation is the utilization ofcharland where no economic crop can begrown except sweet potato, watermelons andmassmelons. The groundnut yield/acre inBangladesh is one of the lowest in the world(Table 3) but the economic return is more fromgroundnut than other oilseed crops.

Climate and Soil

Groundnut thrives in high temperatures (25-30°C). The daily water requirement is about 0.21acre inches which equals 26.1 acre inches for itstotal need (Arakeri et al. 1967). Water needs aremainly met by rainfall. The areas receiving42-54 inches of rain are suitable for its cultiva-tion.

Although groundnuts can be grown through-

226

Table 2. Seed yield and expected oil and protein yields from different oilseed crops in Bangladesh.

Yield/acre (mds)Yield/acre (mds)Yield/acre (mds)

Oil (commercialOil (commercialCrop Yield/acre (maunds) Oil (%) Protein (%) Oil Protein extract able)

Groundnut 16.0 42.2 26.0 5.50 3.40 4.2Sesame 6.3 47.0 20.0 4.01 1.26 2.5Soybean 15.0 22.0 42.0 3.03 6.03 3.0Rapeseed a nd 6.1 38.2 27.0 2.31 1.65 2.0mustard

One maund = 82 lbs = 37.25 kg.

Table 3. Yields of groundnut (in shell) inBangladesh and other countries.

Country Yield/acre (maunds)

Bangladesh 15.0Mauritius 47.1Israel 39.0Greece 31.4USA 30.3

Source: Food and Agriculture Organization (FAO) 1974.One maund - 82 lbs - 37.25 kg.

out the year, their cultivation is more profitablein the rabi season — mid-September to mid-March.

The crop can be grown in all thesoil tracts, butit is mostly grown in charlands, which areavailable adjacent to the rivers. Such soils arewell drained, light colored, sandy to sandyloams with adequate calcium. Dark coloredheavy soils stain the hulls which lowers themarket value of the crop. The cultivation cost ishigh in heavy soils and they give a compara-tively low yield which may be due to unsatisfac-tory penetration of the pegs into the soil and thefailure of nuts and seeds to develop properly.

Cul t ivat ion

Groundnut is a clean tilled crop that needsdeep plowed friable soils. Two to three crossplowings followed by two or three harrow-ings are generally practiced in charlands, but

with highlands the number of soil workingsmay be greater.

Planting Time

A favorable yield and a harvest before the startof the monsoon are obtainable if the winterplanting is sown within the first fortnight ofNovember. In summer, the crop is planted inJune in highlands with well drained soil.

Fertilizers

Groundnut mainly requires N, K, P, and Ca. Itsnitrogen need is comparatively less due tosymbiosis with Rhizobium. The phosphorusrequirement is high as it helps in developingbetter quality seed with a high oil content. Hongand Van Schuylenbourgh reported the role of K as a maintainor of high quality seed. Calciumhas been found to affect the shelling outturn ofthe seeds — a vital requirement for higheryield. Copper and Boron have a positive re-sponse on yield, but their application may notbe possible in Bangladesh and it is better toapply organic manure.

Hobbs (1976) reported that groundnuts makea heavy drain on Ca and gypsum is effective toimprovetheshelling outturn. Moreover, it helpsto reduce the number of pops and empty pods.Khan and Rahman (1968) observed inBangladesh in alluvial soil that the applicationof N, P and K in a ratio of 20:40:40 lbs/acreproduced a high yield and oil content, whileQuader and Islam (1964) reported that theapplication of N, P and K in the ratio of 20:60:60lbs/acre gave a good yield in red soils.

227

Seed Rate Utilization

Groundnut may be sown with or without shell.Experiments conducted in different countrieshave indicated that germination is very low ifthe shells remain with seeds. Plant population/acre is an important factor for yield of nuts.Khan and Rahman (1968) and Quader andKhaleque (1966) using the variety Dacca-1,found that nut production was maximum withan area of 90 sq. inch/plant — 10 inches x 9 inches and 15 inches x 6 inches. Other workershave concluded that 12-15 inch row width anda 4-6 inch spacing between plants were favor-able for high yields.

For spreading types, 20-24 inches betweenrows and 9-12 inches between plants in a row isfavorable. Bunch type groundnuts (mostlygrown in Bangladesh) require a spacing of 15inches between rows and 6 inches betweenplants in a row, thereby accommodating ap-proximately 69 696 plants/acre. It has beenfound that 80-90 lbs of unshelled nut willprovide the desired plant populations per acre.

Cul tu ra l Opera t ions

Groundnut can withstand the average droughtconditions in this region but an irrigation at firstflowering favors yield. One weeding after 30days and another at 45-50 days after sowing isgenerally required. For easy penetration ofmaximum pegs, a layer of 2-3 inches is gener-ally raised up just before the maximum flowersare going to flush.

Diseases

Cercospora leaf spots and Sclerotinia blight arethe principal diseases. Aspergillus flavus at-tacks stored seeds and produces aflatoxin.Jalaluddin (1977) reported that Dithane M 45and copper oxychloride increased yield by 50%and 16%, respectively, when sprayed againstfungal flora.

Ma jo r Pests

These are hairy caterpillars and subterraneanants. The latter are very serious in highlandareas and they cause wilting. Leaf rollers andaphids are also commonly found.

Groundnuts are used as roasted nuts, saltednuts, blanched nuts and in making candies,cakes and cookies.

Edible oil is extracted. In 1976, an oil mill wascommissioned in the District of Mymensingh. Ithas a present capacity of 50 metric tons/dayfrom which 15 metric tons of oil/day can beproduced. The groundnut oil mill does not run atfull capacity throughout the year due to aninsufficient supply of groundnut. The oil is usedin making soaps.

In charland areas of Bangladesh, groundnuttops are used as hay and silage after the harvestof the nuts.

Research and ResearchProblems

Research work on oilseeds and pulses wasstarted by the Bangladesh Agricultural Re-search Institute (BARI) about 1957-58. BARIhas recommended two groundnut varietiesselected from local and exotic sources. TheInstitute has also collected some exoticgermplasms and had undertaken limited vari-ety and agronomy trials.

The Institute of Nuclear Agriculture (INA) inMymensingh has conducted groundnut irradi-ation breeding with the local recommended vari-ety Dacca-1. Some selections of desirable typesare now in the Msgeneration. About 40 varietieshave been collected from India and they arebeing studied for adaptability and yield perfor-mance.

A little work on the selection of high yieldinggroundnut lines has been attempted at theBangladesh Agricultural University.

The Bangladesh Agricultural Research Coun-cil (BARC) completed a survey on the position ofgroundnut production and utilization inBangladesh in 1976 (Anon. 1976). This reportalso dealt with socioeconomic conditions inthe industry and these findings included: 22%groundnut farmers are old, 48% are middleaged and 30% are young; 67% have had noeducation and 17% and 13% have received onlyprimary and high school education, respec-tively; the average farm size was 4.68 acres(range: 0.25-21.50 acres); 98% of the farmersowned their land; 98% procured their seed from

228

themarket; 100% sold their produce in the localmarket; and the low and medium income groupof farmers consisted of 40% and 39%, respec-tively, while the high income group amountedto 21%.

The study also examined the extent of adop-tion of the principal farm practices and it foundthat the use of seed treatment chemicals andfungicides was nil; only 22% of the farmersused manures and fertilizers; 36.7% followedearthing-up practices; 0.16% irrigated theirfields and only 4% used insecticides.

Problems of Groundnut CultivationLow yield is the main problem which is mainlydue to the low genetic potentiality of the cul-tivars, heavy disease infestations particularlyfrom Cercospora leaf spots (both early and late)and Sclerotinia blight, insect infestations, lowlevels of fertilization, no irrigation facilities,inability of the farmers to procure timely andadequate quantities of the required inputs, andfarmer ignorance of the extent of damagecaused by diseases, insects and inadequatefertilizers.

Further Research Needs

There are many requirements. They include theintroduction of adequate germplasm; studieson its adaptation; selection of germplasm andbreeding for high seed yield with high oil andprotein content; resistance to diseases andinsect pests; high N fixing ability and adaptabili-ty to varying soils and climatic zones; researchto develop suitable inocula; and research on

seed viability sothatf armers can keep their ownseed for the next planting.

ReferencesANON. 1976. Survey on the present position of

groundnut production and utilization inBangladesh. Bangladesh Agricultural Universityand the Mymensingh and Bangladesh AgriculturalResearch Council.

ARAKERI, H. R., CHALAIN, G. V., SATYANARAYANA, P., andDONAHUE, R. I. 1967. Page 445 in Soil managementin India. Asia Publishing House, Bombay, India.

HOBBS, P. R. 1976. Page 5 in The ADAB News.

HONG, G. B., and VAN SCHUYLENBOURGH, J. Page 146 in Fertilizer use by JACOB, A. and DEXKULL, H. V., Thirded.

JALALUDOIN, M. 1977. Thesis, Bangladesh AgriculturalUniversity, Mymensingh.

KHAN, I. H., and RAHMAN, L. 1968. Pakistan Journal ofBiology and Agricultural Science.

QUADER, M. A., and ISLAM, W. 1964. Thesis, Faculty ofAgriculture, University of Dacca.

QUADER, M. A., and KHALEQUE, M. A. 1966. Thesis,Faculty of Agriulture, E. P. Agricultural University,Mymensingh.

RAHMAN, A. T. M., and MATIN, M. A. 1976. Dainik

Bangle, Dacca.

RAHMAN, L 1970. Groundnut, a promising oil crop inEast Pakistan (now Bangladesh). Pakistan Journal ofScience 22: 34.

229

Groundnut Production, Utilization, ResearchProblems and Further Research Needs in Burma

U. Win Naing*

Local spreading groundnuts have been sown inBurma since 1880. They are two seeded andthree seeded pod types. The seed color is pink.During the year 1925, some exotic spreadinggroundnuts were introduced into Burma andafter five years of selection, the cultivarM-30/38 was produced.

Erect groundnuts named Small Spanish, BigSpanish, Small Japanese, and Big Japanesehave been grown in Burma since 1920. Later,more exotic erect groundnuts were introducedinto Burma and aftersomeyears of selection SP121/070 was produced at Magwe Central Farm.Distribution to farmers commenced in 1948 andlater it became very popular and spread all overBurma. Some years later, the erect varietiesM-9, M-10, M-11 were produced.

Production

The area sown to groundnuts fluctuates (Table1). The highest acreage sown was in 1973-74when it was 1 973 470 acres. The lowest was1132 300 acres during 1966-67. The maincauses of the fluctuations are the frequentoccurrence of unfruitful rainfall in thegroundnut areas and the very high price of seedgroundnuts in some years.

VarietiesThe following varieties are grown during therainy and winter seasons:

Rainy Season: (1) Erect Type: SP 121/070,M-9, M-10, M-11, and Small Japanese; (2)Spreading Type:- M-30/38, AH-35, KhaungonSpreading, and local spreading.

Winter Season: Erect Type: SP 121/070, M-9,M-10, and M-11. The line M-9 is a selection fromSP 121/070; M-10 was produced from a cross

* Agriculture Corporation, Rangoon, Burma.

between SP 121/070 and S.550-05; and M-11 is a selection from Shawat 21/6.

The characteristics of varieties grown inBurma are shown in Table 2.

Main Factors Affecting Yield

Over 50% of the total area of groundnut is sownas raincrop, under semi-arid region conditions.The rainfall pattern during the crop growingseason favors a fruitful harvest only one year inten. Sometimes there are 25-40 days betweentwo precipitations.

Winter groundnuts are sown on the fertileriverine sides and islands along the Irrawaddyriver. Here the yield rate is 50-100% higherthanrainfed groundnut on upland.

Only a few acres of the total area are fertilizedwith farmyard manure, urea and triple super-phosphate (Table 3).

Utilization

Groundnut oil and sesame oil are the maincomponents used for cooking. Because Bur-mese oil consumption consists of 70%groundnut oil, there is little increase in produc-tion of groundnuts for kitchen consumption.

Research Problems

There are many problems in groundnut cultiva-tion in farmers' fields as well as in the experi-mental stations of the Agricultural Corporation.

To conduct the appreciable amounts of re-quired experiments, the Agriculturral Corpora-tion with the help of UNDP has increased thenumbers of farms as well as research facilitiesand technicians.

In Burma there are two central experimentalstations and five seed farms which are conduct-ing groundnut experiments.

230

Table 1. Area and yield of groundnuts in Burma.

Sown Matured Yield YieldYear acreage acreage lb/acre (25 lb basket)

1975-76 1 693 337 1 633 769 554.5 36 229 4281976-77 1 507 304 1410 357 661.0 37 289 2801977-78 1 418 263 1 391 822 735.0 40 946 2841078-79 1 421 840 1387 911 699.0 38 809 2161979-80 1 493 507 1 468 073 742.0 43 590 0001980-81 1 789 046 1 732 994 793.5 55 010 558(Projected)

Table 2. Characteristics of groundnut varieties grown in Burma.

Life period

Pod

OilLife period L B Midway Oil ShellingVariety Plant type (days) Seed color (mm) (mm) girth(mm) (%) (%)

SP 121/070 Erect 110 Pink 24.7 10.6 9.5 47 71M-9 " 110 25.4 10.9 9.6 59 73M-10 " 110 22.9 10.4 10.0 54 76M-11 " 110 23.5 13.5 10.0 55 75M-30/38 Spread 150 21.6 10.2 9.0 49 70Kyaungon " 150 23.2 9.9 9.3 49 68Local " 170 27.0 13.2 11.2 49 70

spreading

The following types of experiments are beingconducted on these farms in 1980-81: Table 3. Ferti l izer usage in Burma (1955—86

to 1979—80, average).

Amount usedFertilizer (tons)

Raincrop acreagefertilized

Urea 4410TSPa 2500Potash 250

200 000 120 000

a. TSP - Triple superphosphate.


Varietal Improvement

Presently six nucleus stock of erect types andfour nucleus stock of spreading types are main-tained. For genetic stock, we have 70 erect

231

Varietal yield tests.Rhizobium inoculation tests (mainly onCB.756. Australian St.)Lime application and plant types.The effect of levels and carriers of phos-phorus.Residual effect of levels and carriers ofphosphorus on groundnut grown afterthe monsoon rice crop and after themonsoon jute crop.Application of gypsum, nitrogen andphosphorus on erect groundnut.Depth of land preparation on erectgroundnut.Insecticide effects on groundnut leafminer.Effect of weedicides on weeds.Effect of trace elements on groundnutyield.

1.2.

3.4.

5.

6.

7.

8.

9.10.

varieties and 136 spreading varieties.Under selection, we have 45 Australian va-

rities and 15 Japanese varieties, and in hybrid-ization we have six crosses and 101 families.

Maximum yield potential of the present va-rieties used in cultivation is between 2500-3000lbs. The varieties should be improved to get themaximum yield potential up to 4000-5000 lbs.

We have very few nucleus stock and geneticstocks. For proper selection and hybridizationpurposes, more exotic varieties should be in-troduced.

Cultural Practices

Cultivation in rows is usually practiced ingroundnut production. Spacings between rowto row and plant to plant are the prime factors.In most areas, 15 inches x 4 inches row x spac-ing for erect groundnut and an 18 inches x 9 inches row x spacing for spreading groundnutare practiced. Experiments should be con-ducted regionally to produce proper row x spacings.

Uneven spacing and low seed germinationproduce poor results from hand drilling seeds infurrows. An improved seed driller, that givesprecise depth and distance, should be tested.

Fertilizer Experiments

We have some fertilizer experiments ongroundnut at Magwe Central ExperimentalFarm. The last 3 years' experimental resultsgave little indication of nitrogen and phosphatefertilizer uptake. A significant nitrogen rate is 25lbs in combination with 35 lbs of phosphate atMagwe. We still have no significant indicationof the effect of gypsum on yield, but plantsseem to have a deeper green coloration. Experi-ments on yield with nitrogen and phosphatefertilizer at different rates should be conductedfurther in different regions.

Since 1979, Rhizobium experiments havebeen conducted, but we have no significantresults. Experiments on yield with differentrates of gypsum and experiments withRhizobium strains should befurther conducted.

232

Groundnut Product ion, Ut i l izat ion, ResearchProblems and Further Research Needs

in Malaysia

Halim B. Hamat and Ramli B. Mohd. Noor*

Groundnut {Arachis hypogaea L.) is the mostextensively grown grain legume in Malaysia. Itis grown either as a sole crop in the riverine andrainfed rice areas, or as an intercrop especiallyin young rubber. It is an important cash crop inthis country. However, the hectarage has beenstable in the last few years. In 1976, the hectar-age was 5794 hectares in sole crop equivalent(Wong 1979). The major groundnut growingstates are Kelantan (2658 ha), Trengganu (1299ha), and Perak (1106 ha).

Groundnut Product ion Areas

All the Malaysian groundnut crop is grownunder rainfed conditions. Generally, the grow-ing areas are:

Riverine Area

This is mainly along the banks of the Kelantan,Trengganu, Perak, and Pahang rivers. The soil isalluvial and its fertility is replenished every yeardue to the annual flooding during the monsoonseason. This is the most intensive cultivatedarea and it contributes about 60% of the totalgroundnut production.

Rubber and Oil Palm Area

The groundnut is grown as an intercrop inyoung rubber and oil palm plantations, and insmall holdings. Such production is commonlyfound in the states of Perak and Selangor.

Single Crop Rainfed Rice Area

Here the groundnut is grown in rotation withrice during the off season when a second crop is

* Groundnut Breeder and Agronomist, respectively,of the Field Crops Branch, MARDI, Malaysia.

not possible due to insufficient water. This is thepotential area for the expansion of groundnutcultivation. The areas are found in the states ofKelantan, Trengganu, Kedah, and Pahang andare estimated to be about 150 000 hectares(Wong 1979).

Bris Soil Area

Presently a very insignificant hectarage ofgroundnut is grown in this area. However, it isanother potential growing area where thegroundnut can be rotated with tobacco. Thisarea is located along the east coast of Peninsu-lar Malaysia.

G r o u n d n u t G r o w i n g Seasons

Malaysia has an equatorial-type climate,characterized by humidity above 60%, abun-dant rainfall (200-300 cm/yr), temperaturesranging between 22°-31 cC throughout the year,and daylength of about 12 hours. Generally, twocrops of groundnut can be grown per year.

In the East Coast states of Kelantan andTrengganu where 60% of the annual rainfalloccurs during the North-East Monsoon(November-March), 26% during the South-west Monsoon (May-September) and only 14%during the two transition months (April andOctober) (Dale 1974), the first planting (main)season begins in late January or early Februaryand the crop is harvested in April. The secondplanting season begins in late May or early Juneand the crop is harvested in September. Gener-ally the groundnut produced from the firstplanting season is of better quality than thesecond season (Anon. 1977).

In the West Coast states of Perak, Selangorand Kedah where 36% of the annual rainfalloccurs during the North-East Monsoon, 4 1 %during the South-West Monsoon and 23% dur-ing the transition months (Dale 1974), the first

233

planting season begins in April or May and thecrop is harvested in July or August. The secondplanting season begins in September orOctober and the crop is harvested in January.Generally, the hectarage is greater in the sec-ond season because the farmers grow more tocater for the demands of the Chinese festiveseason which occurs in February. Despite thissecond season being less suitable for the grow-ing of groundnut than the first season due tohigher incidence of diseases, the selling priceis higher (Ramli et al. 1976).

Although two crops of groundnut are possi-ble per year in most parts of the country, usuallyonly one crop is feasible if it is grown in rotationwith other crops. In the rainfed rice area of theEast Coast where it is rotated with rice, thegroundnut is usually planted in April or May andthecrop is harvested in August or September. Inthe Bris soil area where it can be rotated withtobacco, the growing season is also similar tothat in the rainfed rice area.

C u r r e n t P r o d u c t i o n P r a c t i c e s

A number of cultivars are grown by farmers. Inthe state of Perak, the most common cultivarsare Sungai Siput and Mengelembu, which aremainly marketed as roasted groundnut. Inother states, cultivars that originated fromIndonesia are commonly grown. PresentlyMARDI is recommending three cultivars — V13, Matjam and 47-5 — for growing through-out the country. They are of the Spanish bunchtype with small/medium two-seeded pods. Far-mers usually obtain a yield of 3.0-3.75 metrictons of fresh pod per hectare, though a yield of 6 t/ha has been recorded. The national averageyield is 2.2 t/ha and this is among the highest inAsia.

In land preparation, generally either oneround of plowing and one round of rotovation,or two rounds of rotovations are practiced. A square planting of 30 cm x 30 cm with twoseeds per point giving about 220 000 plants/hais usually practiced. This requires approxi-mately 90 kg seed/ha. MARDI presently is rec-ommending a row planting of 50 cm x 10 cmwith one seed per point giving about 200 000plants/ha.

Liming using dolomitic limestone at the rateof 1-2 t/ha and fertilizer at rates of 34 kg N, 56 kgP2O8 and 56 kg KaO in the forms of sulphate of

ammonia, triple superphosphate and muriateof potash, respectively, are usually recom-mended for most soils. Liming is done duringland preparation at two weeks before planting,and fertilizer is applied at planting, in band.However, liming and fertilization are seldompracticed by the farmers especially in theriverine areas. If practiced, there is no standardrate of application. Usually a compoundfertilizer is broadcasted immediately afterweeding, one month after planting. Hilling ispracticed during the weeding operation.

Insect pest and disease control is seldomcarried out because the problem is usually notserious. Disease like Cercospora leaf spot usu-ally occurs very late in the season and has littleeffect on the yield. However, if the diseaseoccurs early in the season, it can be effectivelycontrolled with benomyl fungicide.

The groundnut is harvested 90 days afterplanting for use as roasted groundnuts andabout 105 days after planting for use as plantingmaterial.

Costs of production and returns fromgroundnut vary greatly depending on the oper-ations carried out, yield and the current sellingprice. However, groundnut generally gives a good net return ranging from M$625 to 1000/haper season (Anon. 1977; Ramli et al. 1976).

Groundnut Usageand Ut i l izat ion

Most of the Malaysian groundnut production ismarketed as fresh, unshelled pods. They areused mostly for roasted groundnuts. Some areused for making cooking oil, oleomargarine,and confectionery. A special technique calledthe Mengelembu process has been developedfor roasting groundnuts. There are about tenfactories scattered all over the groundnut pro-ducing areas. Factories sometimes obtainadvance commitments by providing cash ad-vances and planting materials to selected far-mers. Ex-farm groundnut prices vary accordingto locality, season and nut quality. The roastedgroundnuts are mainly consumed locally, butsome are exported to other countries.

Research Ac t i v i t y

At present, groundnut research activity is

234

focused on breeding and varietal evaluation, de-velopment of cultural and management prac-tices, nutrient requirement study, insect pest,disease and weed control studies.

B r e e d i n g a n d V a r i e t a l E v a l u a t i o n

Virtually all the past work on varietal improve-ment had been varietal evaluation of foreigncultivars. After many years of evaluation, threecultivars were found to be high yielding. Theseare V13, Matjam and 47-5 and they arecurrentlybeing recommended to farmers. V13 is a localselection, Matjam originated from Indonesiaand 47-5 originated from Senegal. These threecultivars perform well throughout the country.

Recently, a breeding program has been initi-ated. The breeding materials are evaluated atseveral locations in the groundnut growingarea. This is because the environmental condi-tions and the problems of each area are differ-ent. The objective of the breeding program is todevelop high yielding cultivars for specificareas.

To complement this program, germplasmfrom different ecogeographical regions is beingevaluated. Presently there are 256 accessions inour germplasm collection, of which 200 wereobtained from ICRISAT. Some of these acces-sions have been included in advanceyield trialsover years and locations. A number of them arebeing used as parents in the breeding program.

D e v e l o p m e n t o f C u l t u r a la n d M a n a g e m e n t P r a c t i c e s

There was limited work on cultural and man-agement practices carried out in the past. Theinvestigations were mainly on plant spacing/density and harvesting time studies conductedon well-drained upland soils. Presentlygroundnut production has expanded to otherareas like the riverine, single crop rainfed riceand the Bris soil areas. Since each area offersdifferent ecological environments and produc-tion problems, there is a need to developcultural and management practices suitable foreach specific area.

Nutrient Requirement Studies

Some work has been done on the nutrientrequirements of groundnut. The present rec-

ommended rates of fertilizer application havebeen based on these findings. Since differentsoil types and locations differ in their nutrientstatus, nutrient requirement studies are re-quired over many locations to determine op-timum rates for each specific location. Alsothere is a need to study the inoculation re-quirements of rhizobium bacteria for successfulnodulation so that the beneficial effects ofnitrogen fixation by these bacteria can beexploited and thus reduce the costs of nitrogenfertilizer application.

Insect Pest Studies

In recent years, research has been focused onthe identification of some of the more importantinsect pests and their chemical control. Some ofthe recommended insecticides are not as effec-tive and also there have been reports of fieldresistance to some of the chemicals by theinsect pests. New chemicals, therefore, need tobe screened as a stopgap measure. Followingthe availability of effective insecticides, moreresearch should be devoted to screening forvarietal resistance. As part of a long termcontrol program, the role of natural enemiesalso needs to be investigated.

D isease S t u d i e s

Much of the research effort on disease prob-lems over the years has been the identificationand diagnosis of the prevalent diseases. Chemi-cal control has been effective for some dis-eases. However, for many other diseases, ap-propriate control measures are still lacking orhave not been investigated. Perhaps the idealcontrol measure would be through varietalresistance. However, little has been done toutilize this attribute.

Weed Control Studies

Research on weed control in the past has beenconducted on well-drained upland soil. It hasbeen found that a preemergence application ofalachlor plus one round of manual weeding attwo weeks after planting is adequate for thistype of ecological environment. However, in-formation on weed control is lacking for theother groundnut growing areas. Weed surveysneed to be carried out to determine the major

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weed species in these other areas. Traditionally,weeding is done manually. Therefore, researchneeds to be conducted to determine the righttime and frequency to maximize crop yields.Also there is a need to screen other herbicidesand todetermine their efficacy to control certainprominent weeds.


The above research activities are those cur-rently being given priorities. However, we alsorecognize other areas where attention is re-quired in order to promote the expansion ofgroundnut cultivation in the country. One sucharea that needs immediate attention ismechanization. Except for land preparation, allaspects of groundnut cultivation are done manu-ally. Planting and harvesting are the two mostlaborious and time consuming operations. Inrainfed single crop rice and other low lyingareas, waterlogging is a constant problem. Toovercome it, the groundnut can be planted onridge or raised beds. Therefore, there is a needto develop a suitable and practical ridger orbedformer. In addition, fertilizer application andspraying to control weeds, insect pests anddiseases can also be mechanized. Attentionshould be given to mechanizing these oper-ations.

It has been recognized that groundnut cannotbe grown alone in an area, continuously.Groundnut cultivation needs to fit into a crop-ping system with other crops. It should bedetermined whether groundnut is suitable forcultivation after rice, tobacco and other annualcrops. Also, there is a need to know the benefitsof intercropping groundnut with other crops,whether they be annual or perennial.

To further promote groundnut cultivation,there is a need to expand its usuage and utili-zation in the country. The present groundnuthectarage is about to saturate the market forroasted groundnut. There is a need to look fornew ways of utilizing groundnut to make otherproducts.

SummaryGroundnut is the most extensively grown grainlegume and it is an important cash crop in thecountry. However, the hectarage has been sta-ble in the last few years. Previously, groundnutwas mainly grown in young rubber, oil palmand riverine areas, but now its cultivation hasexpanded to rainfed single crop rice areas. AlsoBris soil regions are another potentialgroundnut growing areas in the future. Gener-ally, two crops of groundnut can be grown peryear throughout the country. However, if grownin rotation with other crops only one crop ispossible. Although there are recommendationsavailable for growing the crop many farmersseldom follow the recommended practices dueto socioeconomic problems. The crop is mainlyused for roasted groundnut.

Research activities being currently em-phasized include breeding and varietal evalu-ation, development of suitable cultural andmanagement practices, nutrient requirementstudies, and insect pest, disease and weedcontrol studies. Our overall research objectiveis to develop technologies to obtain maximumyields for specific growing areas. In order topromote the expansion of groundnut cultiva-tion in the country, further research shouldinclude mechanization, cropping systems andgroundnut utilization.

Re fe rences

ANON. 1977. Groundnut cultivation in Kelantan. Page 6 (In Malay, unpublished).

DALE, W. I. 1974. The rainfall of Malaya, Part I. Pages132-144in The climate of West Malaysia and Singa-pore.

RAMLI, M. N., ABU KASSIM, A. B., ABDULLAH, C. T.,and ZAINOL, A. A. 1976. Report on visit to Perakgroundnut growing areas (unpublished).

WONG, L. J., ABDUL RAHMAN, D., JAAFAR, D., ZULKIFLY,Z., and XAVIER, N. 1979. Research towards farmingsystem in rainfed or single cropped rice area. MAROISenior Staff Annual Conference 11-13 Dec 1979(Mimeo).

236

Groundnut Product ion, Ut i l izat ion, ResearchProblems and Further Research Needs in Thai land

Arwoo th Na Lampang, Terd Charoenwatana andDumrong Tiyawalee*

There is no definite record about peanut intro-duction into Thailand. However, it is believedthat peanut was brought into this country byEuropean traders during the Ayuthya period— about three hundred years ago. Peanut iswell adapted to tropical climate and at presentis cultivated in every part of the country. TheThai people consume nuts in various forms. Thearea (ha), production (metric tons), and yield(kg/ha) in the past decade are given in Table 1.The figures indicate an insignificant change inproduction during this period. Table 2 showspeanut production and consumption projectedfor the next 5 years.

Product ion

The major growing regions are the North andCentral Plains, and the Northeast. In the South,heavy rainfall seems to limit large scale produc-tion. Nevertheless, isolated fields of peanut aregrown for local consumption, mainly in theyoung rubber replantations. Figure 1 illustratespeanut production in these four regions. Thelarge hectarage falls between latitudes 13 and20 degrees North.

Soils suited for growing peanut are generallylight to medium texture and well drained.

The Thailand climate is divided into twodistinct seasons — dry and wet seasons. Themonsoon or rainy season begins in May andlasts till October. This is the critical time for Thaifarmers since about 80% of the total arablelands depend mainly on this rainfall. The dryperiod covers the remainder of the year when

* Director, Field Crop Division, Department of Ag-riculture, Bangkok; Vice Rector, Khon Keen Univer-sity, Khon Kaen; and Dean, Faculty of Agriculture,Chiangmai University, Chiangmai, Thailand,respectively.

crop cultivation, except in a small area, can beundertaken only with irrigation. This areaamounts to about 20% of the total cultivatedland. Thus peanut is grown in both seasons.

Table 1. Area, production, and yield of peanut(In the pod) during the 10-year period(1969-1978) .

Area Production YieldYear (000 ha) (000 t) (kg/ha)

1969 103 124 12061970 104 125 12001971 114 136 11691972 119 153 12881973 124 147 11811974 130 161 12371975 118 147 12061976 122 151 12441977 103 105 10311978 106 127 12061979 - 132 -

Source: Office of Agricultural Economic Report 1960, Minis-try of Agriculture and Cooperative.

Table 2. Projected peanut production (In thepod) and consumption in the next5-year period (1980-1984).

Year (000 t) (000 t) (000 t)

1980 150 124 261981 159 127 321982 173 133 401983 187 138 491984 203 143 60Rate + 8% + 3.7% + 23%

Source: Ministry of Commerce, 1980.

237

Figure 1. Peanut production divided by re-gions in the Kingdom of Thailand. Source: Office of Agricultural Economic Report 1978, Ministry of Agriculture and Cooperatives.

In the rainy season, planting is from May-June and harvest is in September and October,while in the dry season, planting is fromJanuary - February with harvest in March andApril, in paddy fields after rice.

Since there is no specific requirement fortypes of peanut in the markets, the mediumseeded types are generally grown to satisfy a multipurpose demand. Three cultivars havebeen released to farmers at present. Two of

them are Valencia type, S.K. 38, red seed coat,and Lampang, white seed coat, and one cultivarof bunch Virginia, Tainan 9, a white seed coat.They are well received throughout the country.However, the small seeded Spanish type isoccasionally seen in certain locations. Attemptsto grow large seeded Virginia runners have notbeen successful due to the longer duration andproblems of unfilled pods.

Thai farmers grow peanut as mono or solecrops in the upland during the rainy season, andas mono crop followed by rice in the dry season. A spacing of approximately 30 cm between rowsand 20 cm within rows does not permit inter-cropping. Recently, experiments on intercrop-ping of peanut with other row crops such ascassava, cotton, sugarcane and castor beanappear promising for practical development,based on LER (Land Equivalent Ratio).

Peanut is less vulnerable to serious diseasesand insect pests compared with other legumes.Its relatively early maturity, about 110 days,allows it to escape severe attacks of Cercospora leaf spot and rust which become serious andwidespread late in the rainy season. Seedling,stem and collar rots may occur during the peakof the rainy season, if land is not properlydrained. Leaf hoppers, rollers and miners createconsiderable problems during the dry period.Systemic insecticides are recommended fortheir control. Since harvesting of both the sea-son crops occurs in the dry periods, the aflato-xin hazard is minimized.

Other factors which make peanut widelyadapted in Thailand are its ability to withstandintermittent moisture stress, low soil fertility,low pH and/or soil salinity as well as minimalmanagement. Also it can withstand atmo-spheric drought for 2-3 weeks and resumegrowth immediately with good rains.

Most Thai farmers treat peanut as a marginalcrop, especially in the rainy season. Hence,yields are low. In contrast, the Thai farmerprefers to grow peanut in the paddy fields,wherever irrigation is available, because of thevigorous growth of the following rice crops, inaddition to the extra income from peanut.

Thailand imports considerable amounts ofunrefined peanut oil and cake, and exports bothshelled and unshelled nuts. Table 3 gives thetrade balance during 1975-1979 and Figure 2 shows sharing relationships between thefarmer, dealer, shelter and exporter.

238

Uti l izat ion

Peanut utilization in Thailand is relatively simi

lar to that in other countries. There are numer

ous forms and preparations employed in the

processes to obtain the finished products start

ing with either the whole pod or shelled nuts.

Whole Pod (Unshelled)

BOIL. Fresh pods from the fields are boiled or

steamed, and a small quantity of salt is added as

flavoring. The cooked pods are drained out and

immediately put on sale as snack. This kind of

preparation is simple and popular to street

retailers or vendors.

BOIL AND DRY. The above products cannot be

kept for a long time. Processors have to dry the

cooked pods under sunshine and/or in the oven

to reduce the moisture content in the pods to a

certain limit. They are packed in airtight plastic

bags to prolong their keeping quality. Thailand

recently started to export this type of product to

neighboring countries. There is a continuously

increasing demand.

ROASTED PEANUTS. Large and medium pods

are sorted out from the dry bulk. Then they are

roasted, usually with hot sand. The product is

vended directly and/or kept in plastic bags for

transportation to other places.

Shelled Nuts

Peanut is generally stored in the pod. At the

Source: Ministry of Commerce 1980.

Figure 2. Shares in peanut exportation

(based on 1980 data).

processing plant, the pods are shelled and nuts

are removed from the shells or hulls. The nuts

are graded into three classes according to their

sizes:

LARGE AND MEDIUM SEED SIZES. These are

mainly used in the form of whole nuts and they

command premium prices. They are prepared

for snacks by deep frying, roasting and/or bak

ing and for making confectioneries and des

serts.

SMALLANDBROKEN NUTS. These are ground or

milled to make peanut meal. The meal is

converted into pastes, curries, desserts and

several forms of snacks.

Table 3. Balance of peanut trade during the 5-year period (1975-1979).

Import Export

Production

(dry pod, 000 t)

(as pods

Dom Consump.

(000 t)

(as pods)

Year

Production

(dry pod, 000 t) (000 t) Million β

Dom Consump.

(000 t) (000 t) Million β

1975 142 30 36 133 9 86

1976 151 92 100 140 12 94

1977 105 95 149 82 24 166

1978 127 26 33 92 36 206

1979 131 29 46 117 15 104

Source:

Note:

Custom Department, Ministry of Finance, 1980.

1 U.S.S = 20 β

239

OIL EXTRACTION AND FEED M E A L Due to an

increasing demand for edible oils and animalfeeds in the past decade, oil extraction indus-tries were established to extract peanut andother edible oils. However, peanut costs con-siderably more than other sources of oil such assoybean and rice bran. At present, peanutsenter the trade mainly for human consumptionin both the domestic and foreign markets aswhole nuts.

To a lesser extent, peanut is used in specialforms, such as fermented paste and sprouts.

The feed industries used to import peanutcake in large quantities as a substitute forsoybean cake. The restriction of aflatoxin im-posed in the last few years has led to a con-siderable reduction of imports.

Research Problems

The Thai government is planning to increasepeanut production for both domestic consump-tion and export. The attention to and invest-ment in this crop is inadequate at present,especially from the research standpoint. Thereare several constraints to be removed beforehigher levels of yield can be obtained.

In regard to varietal improvement, thefollow-ing characters are needed — high, reliable,consistent yields; earliness (i.e., about 90 days)to fit existing cropping patterns; uniform flow-ering, pod setting and maturity; resistance tomajor pests and diseases, including Aspergillusflavus; and higher shelling percentage.

Research is required on cultural practices andcropping systems to minimize labor and otherinputs, obtain higher LER, maintain soil fertility,and to spread the farm labor requirement and

thereby reduce peak demand. Small and animaldrawn equipment such as the planter, poddigger, pod picker and shelter need to be re-searched.

Constraints imposed by diseases, insectpests and weeds constitute important prob-lems.


Increased research on peanut is urgentlyneeded in order to increase yield per unit areaas well as the national product. The goals forfurther research are:

1. Develop larger seeded varieties with a shorter growing season.

2. Study the peanut cropping system in therainfed areas, which occupy about four-fifth of arable lands in the Kingdom. Atten-tion must be paid particularly to the North-east, where soils are relatively infertile andrainfall is erratic.

3. Improve or maintain soil productivity bythe application of rock phosphate andother sources of phosphorus (in additionto Item 2).

4. Research on minimizing aflatoxin con-tamination by means of breeding, culturalpractices, storage and detoxification bychemical treatment.

The above goals require a strengthening ofresearch facilities involving (1) staff training inshort term and academic programs, (2) coordi-nation at international and national levels withpeanut research institutes in the exchange ofgermplasm, seeds, materials, information andresearch results, and (3) the establishment ofregional yield trials.

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in Argent ina

Jose R. Pietrarel l i*

Product ion

For the past fifty years, groundnut cultivation inArgentina has been concentrated in the centralregion of Cordoba province and in eight de-partments located therein. During this period,small areas have been sown in other provincesof the Northeast, Northwest and ArgentineLitoral. However, they constitute only 2-3% ofthe total area of the country with 97-98% of thetotal sown hectarage being located in C6rdoba.

Since 1970, the average area harvested hasbeen 346 125 hectares per annum with an aver-age annual production of 280 787 metric tons ofshelled groundnut, which represents an aver-age annual yield of 811 kg/ha. The sowingrecord in this past decade was 428 000 hectaresin 1977-78. In the 1978-79 season, only329 000 hectares were cultivated while in1979-80, only 281 000 hectares were har-vested. International markets, lower prices andless demand by the oil industry are expected tocause a further reduction in the area sown togroundnut.

Cordoba Region Product ionCharacterist ics

The region is furrowed by the First and Secondrivers which run to the northeast, and by theThird river which flows to the southeast.

The soil is generally classified as brown, isdeep and is without much impermeable cover-ing. The texture is sandy loam. The alluvialssituated in the regions are sandy. Soil organicmatter content varies and it averages about 2%.The soils are well supplied with calcium, mag-

* Agronomist, INTA, Manfredi Research Station,Manfredi, Argentina.

nesium and potassium but the levels of nitro-gen and phosphorus range from moderate tolow. The ground surfaces utilized are mostlylevel. In a few cases, the slope varies from1 to 3%. The soil type is such that the land iseasily eroded by wind or rain.

The region is semi-arid. Rainfall ranges from600 to 800 mm annually and falls generally be-tween October and March. There is great vari-ability in the time, amount and rainfall distribu-tion each year which results in yield variations.The coldest month is July, with an averagetemperature of 9-10°C. The hottest month isJanuary, with an average temperature of 23-24°C. The frost free period is 245 days. Frostsnormally occur in May but in some years maycommence in April. Because rain falls in thespring and summer seasons when highertemperatures occur, groundnut can be suc-cessfully cultivated in the Cordoba region.

Sowing is favored with a spring which issufficiently humid in order to plant thegroundnut in November or the first days ofDecember. The fall-winter period is dry enoughto permit harvest and natural drying of theproduct under good conditions. The areas sownrange from 100to 150ha. Minifunds exist whichallow a medium extension of 50-100 ha.

The monoculture areas are located on thesides of the Second and Third rivers. Themonoculture of groundnut is characterized by a security of cropping.

Agr icu l tura l Equipment

In the Cbrdoba region, there is a high degree ofmechanization. Equipment is used for tillage,sowing, cultural practices and the applicationof herbicides and fungicides. The equipmentusually consists of plows of 4 or 5 colters,harrow-plows, teeth-harrows, rotary hoes,sowing machines for small and large grain (up

241

to seven rows), and rowing rakes of lateraldischarges, etc.

About 30% of the growers have digger-shaker-windrow machines, and 20% havetillersor peanut combines. Growers who do not pos-sess these last named machines, employ con-tractors.

HarvestAbout 90% of the area cultivated withgroundnut is harvested with a digger-shaker-windrower which works from 3 to 5 rows. Thatsame percentage is picked with a peanut com-bine. The rest of the production is prepared witha stackpole, especially in the monocultural area.

Principal Variet ies

The cultivars grown in the Cordoba regionbelong to Arachis hypogaea, subsp fastigiata vars fastigiata and vulgaris. Colorado comunand Blanco Rio Segundo are the most exten-sively used cultivars (about 50%;. These twovarieties were present prior to the commence-ment of varietal improvement (breeding) at theManfredi Experimental Station. Their culti-vation must be very old. They are perfectlyadapted to the ecological conditions of thecentral region of Cordoba.

Other varieties sown in this area are allproducts of the Manfredi Experimental Station.Colorado Manfredi was obtained by selectionfrom Colorado comun, and occupies 5% of theplanting area. Blanco Manfredi 68 originatedfrom the crossing of a black groundnut (type 4)with a Virginia type line (Fla. 249-40-B3). Itoccupies 15% of the area. Colorado IrradiadoINTA comes from a mutation induced by X-raysin the variety Colorado Manfredi and it occupies20% of the planted area.

The other varieties — Colorado CorrentinoINTA (a selection from a population grown inthe province of Corrientes), Blanco Asuncion(a selection from a population grown inParaguay), Manfredi Virginia 3-INTA (agenealogical linefrom North Carolina, USA andManfredi), Virginia 5-INTA (a product of a selec-tion performed in Florida, USA, and introducedinto Argentina in 1964 with the pedigree Fla.416-2) — occupy the remaining 10% of thegroundnut producing area of Cordoba. The lasttwo mentioned varieties have increased inhectarage more than the others.

Ut i l izat ion

Producers sell their kernels to buyers, who storethem, as well as to cooperatives or associationsin the region, who in their own time sell theproduct to industry. In the groundnut region ofCordoba, there are eight oil factories whoseprimary input material is groundnut. Threeyears ago, the oil industry absorbed about 75%of the total production.

Research Problems

The greatest percentage of the area is plantedwith varieties of the subsp fastigiata. Problemsassociated with this type are (a) no seed dor-mancy with a consequent sprouting risk; (b)fragility of the pegs which causes great yieldlosses due to the easy separation of pods fromthe pegs; (c) generally a low fat content; (d) lowyield potential; and (e) high susceptibility toleaf spot attacks by Cercospora arachidicola and C. personata.

Groundnut diseases and insect pests do notyet represent a grave danger, but late attacks ofleaf spot are common. Occasionally, when theseattacks occur early (early leaf spot) in the vegeta-tive cycle, yield is affected. In the past threeyears, isolated cases of a scab (Sphace/oma arachidis) infection have been found. It appearsto show a preference for certain varieties. InCbrdoba, rust (Puccinia arachidis) is not found.Root rot and pod rot, produced by differentorganisms, are seasonally present undermonoculture or during adverse climatic condi-tions in the maturing period of the pod.

Regarding insect pests, few cases exist ofdamage by subterranean insects {Diabrotica speciosa Germ.), or by the small red spider(Tetranychus telarius) which is present es-pecially during long dry periods.

With the present harvesting machines there isa loss of up to 30% of the harvested material.Also the picking and shelling operations simul-taneously reduce quality and aggravate thedanger of aflatoxin contamination.

Inst i tu t ions w i t h Research Projects

Since 1944, the Manfredi Experimental Stationin Central Cbrdoba province has been respon-

242

sible for varietal and cultural improvements ofgroundnut. Other Experimental Stations whichlike Manfredi are dependent on INTA and whichare situated in different provinces, conductyield testing on different varieties provided bythe Manfredi Experimental Station.

The INTA Microbiology Institute in Castelar(province of Buenos Aires) analyzes grades ofaflatoxin infection in groundnut samples fromgrowers with fields in Cordoba; they also iden-tify varieties and lines of groundnut with possi-ble resistance to the toxin.

The Botanical Institute of the Northeast inCorrentes conducts research on the physiol-ogy, cytogenetics and cytotaxonomy of thegenus Arachis.

Manfredi Experiment Stat ionResearch Projects

The station is responsible for the developmentof new cultivars by selection, intervarietal andinterspecific crossing. A collection of about1500 accessions of Arachis hypogaea is main-tained. Between 1977-80, another 180 sampleswere accumulated in the NW of Argentina,Bolivia, Paraguay, Brazil and Peru. All this mate-rial is sown each two or three years. There isalso a living collection of a wild species of

Arachis and of interspecific hybrids between A hypogaea and A batizocoi.A. cardenasii and A spegazzini. These last named hybrids wereobtained at the North Carolina State University,USA and have been used in interspecific cros-ses with varieties belonging to the subspeciesfastigiata.

The station also investigates the improve-ment of production methodology especiallysowing density, row spacing, digging and pick-ing machinery, natural drying, rotations andirrigation.

Research is conducted on diseases that attackthe overhead and subterranean parts of thegroundnut. These studies include chemical con-trol measures and the evaluation of diseaseresistance in lines and varieties. Work is alsoconducted on soil deficiencies and herbicideevaluations.


One of the earlier goals was the attainment of a high oil content in new varieties. Now, researchis being directed to finding varieties with a kernel of high quality and adequate size fordirect consumption, and to meet the demandsof the international market.

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Groundnut Product ion, Ut i l izat ion, ResearchProblems and Further Research Needs in Brazil

A. S. Pompeu*

Product ion

Although peanuts are an important source ofprotein and oil, Brazilian production has beendecreasing since 1972. Between 1972 and 1978,the cultivated area declined by 66.8% and pro-duction fell by 66% (Table 1). Production de-creased due to a reduction in the cultivatedarea, mainly in the State of Sao Paulo, theleading peanut producer. Changes in stategovernment priorities and a shifting interestamong farmers toward more profitable crops,e.g., soybeans, were responsible for this de-cline.

Sao Paulo State was responsible for 70% ofthetotal production in 1978. Two other principalpeanut producing states were Parana and MatoGrosso do Sul, which accounted for 15.5% and7.7% of the Brazilian production, respectively(Table 2).

Peanuts are cultivated twice a year in thestates of Sao Paulo, Parana and Mato Grossodo Sul, — in the rainy season with sowingstarting at the end of August, and in the dryseason beginning late January or early Feb-ruary. During 1978, 74.2% of production camefrom the rainy season crop.

Although the average Brazilian production in1978 of 1290 kg/ha may be considered low whencompared with 2958 kg/ha in the 1978 USA crop,this is not entirely true if the cultivation systemadopted in Brazil is considered. Peanuts areplanted in small rented areas ranging from5 to 30 ha using a low level of farm technology.

The northwest of Sao Paulo State is thetraditional region of peanut production. How-ever, recently peanut cultivation has expanded

* Genetics Department, Instituto Agronomico, P.O.Box 28,13 100 Campinas, S.P., Brazil.

Table 1. Brazilian peanut production, har-vested area, and yield, 1972—78.

Production Harvested area YieldYear (t) (ha) (kg/ha)

1972 956 200 758 600 12601973 589 887 506 083 11661974 452 722 373 637 12111975 441987 345 095 12801976 509 905 371465 13721977 320 721 228 747 14021978 325 197 252 000 1290

Source: Institute Braslleiro de Geografia e Estetistica (1975,1976, 1978), Institute de Economla Agrfcola (1972),Food & Agriculture Organization (1978).

toward the northeast region of this state infields ranging from 300 to 500 ha cultivated dur-ing the rainy season by growers who are able toapply a better level of technology. The produc-tivity of these new fields has varied from2200 to 2500 kg/ha.

Uti l izat ion

Distribution and utilization details of the 1979crop, estimated to be 450 000 metric tons (t) arepresented in Figure 1. It was calculated that 10%of the total production was retained by growersfor new plantings, 74% went to industries for oilextraction, 11 % was consumed (roasted, salted,candies), and the remaining 5% was exportedwith and without shell. The refined peanut oil isused in human nutrition. A by-product in the oilrefining process is used for making soap. Thepeanut cake — residue from oil processing— is used for livestock feeding.

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Source: CACEX (1980).

Figure 1. Brazilian peanut production flowchart, 1979.

Research Problems

Although peanuts are produced in at leastthe following 11 states of Brazil — Sao Paulo,Parana, Mato Grosso do Sul, Rio Grande do Sul,Minas Gerais, Bahia, Goias, Ceara, Sergipe,

Paraiba and Santa Catarina — research on thiscrop has been conducted only in the stateof Sao Paulo. In order to increase yield, itis necessary to establish multidisciplinaryteams consisting of at least a breeder,phytopathologist, agronomist, and an en-

245

tomologist, at state levels. These teams woulddetermine the limiting factors for peanut pro-duction and propose solutions.

In general, the following topics should betaken into account for a research program inBrazil — introduction and evaluation ofgermplasm in the producing states; identifica-tion of the factors affecting yield, e.g., diseases,insects, and their importance; effects of liming,irrigation, fertilization and organic matter onyields; control of the aflatoxin producing fun-gus Aspergillus flavus; determination of thebest sowing time within seasons, and bestpopulation densities; production systems andcrop rotation; and breeding for disease andinsect resistance. The Cercospora leaf spotscaused by C. arachidicola and Cercosporidium personatum are the important diseases. Amongthe insects, the thrips, Enneothrips flavens, is a serious pest in reducing peanut yield in S. PauloState.


Other peanut research needs should take intoaccount the interaction of peanut x Rhizobium, integrated control for peanut pests, breedingfor resistance XoAspergillus flavus, breeding forearliness, breeding for changing peanut oilcomposition, and monitoring potentially im-portant diseases such as rust.

246

Peanut Product ion, Ut i l izat ion, ResearchProblems and Further Research in Venezuela

Bruno Mazzani*

Product ion

Peanuts were probably grown in Venezuelabefore the Spanish colonization occurred.Arawak Indians were responsible for spreadingpeanuts from its southern center of origin to theCaribbean region. Until recently peanuts havebeen commonly produced on a family scale bysmall farmers all over the country. Modernmechanized production on a large scale com-menced only 20 years ago, following successfulexperiments on peanut adaptation to the ecol-ogy of the eastern Llanos region of Venezuela.This region which is characterized by sandysoils of low fertility, has a rainy season of about1000 mm which is unevenly distributed fromMay to November. This is followed by a dry sea-son (November-May) with practically no rainat all. The region includes more than a millionhectares. The altitude ranges from 70 to 300 m above sea level and the topography is flat orsmoothly undulating.

The yield of rainfed peanuts is highly variable,ranging from 700 to 1800 kg/ha (Table 1). Produc-tion area figures for the states, expressed as a percentage of the total, are Anzoategui 85.1;Monagas 10.1; Falcon 1.4; Miranda 0.2 andothers 3.2. Eastern Llanos, where Anzoateguiand Monagas states are located, account for95.2% of the total area. Irrigated peanuts coverabout 25% of the total area. Yields of irrigatedpeanuts are over 4 t/ha and are less variablethan yields of rainfed peanuts. The latter aregrown on fields 10-500 ha in size while irri-gated peanuts are produced on fields rangingfrom 50 to 300 ha.

The main cultivars grown are Florunner (irri-gated) and Red Starr (rainfed). Seeds of bothcultivars are imported from the United States.

* Centra Nacional de Investigaciones Agropecuarlas,HA, Maracay, Venezuela.

Table 1. Peanut production in Venezuela.

Production Area YieldYear (metric tons) (hectares) (kg/ha)

1962 1805 1 924 9381966 2 254 2 300 9801970 7 077 9 700 7291974 27 781 30 701 9081978 25 833 18 000 14351979 27 000 (e) 14 684 (e) 1839

(e) estimated.

The local cultivar 15607 is also grown on a smallscale from seed produced in Venezuela. Seedrates are 60-120 kg/ha. Inoculation of seeds isnot practiced. One t/ha of lime and one t/ha offertilizer (6-12-6 or similar) are currently appliedto the soil before sowing.

Weeds are controlled by herbicides, appliedas pre-emergence or incorporated into the soilbefore sowing. Weekly applications of fungi-cides and insecticides afford effective controlof diseases and harmful insects. No hand laboris used. Cultural practices from land prepa-ration to harvest combining are mechanized.

Two interesting effects of the introduction ofpeanut culture to Eastern Llanos are: (Da rapidimprovement in soil fertility and texture and(2) the composition of the savannah flora israpidly changing as a number of new speciesappear on the peanut fallow. The old species aredisappearing from the fallows.

Uti l izat ion

Approximately 50% of the crop is processedfor oil and residual meal production. Thebalance is used for direct consumption asroasted peanuts and other confectionery pro-

247

ducts. Sometimes the haulms of peanut plantsare recovered after combining and baled as hayfor feed. Its nutritive value is highly regarded.

Research Problems

Current research is performed in several experi-ment stations directed by the Ministry of Ag-riculture and universities. The main problemsbeing faced include different aspects of peanutgrowing such as crop rotations, disease andpest control, chemical weeding, varietal resis-tance to leaf spots and rust, soil amendmentsand fertilizers, and seed inoculation.

The results of research on peanuts have beenand are being published in a number of papers.Their contents according to the most importantaspects give an idea of the research beingconducted. The subject matter and the numberof papers which have been published for thesesubjects are: soils and fertilizers, 35, breeding,23; cultural practices, 14; diseases and pests,11; experimental techniques, 6; weed control,10; Rhizobium and nodulation, 6; haymaking.

4; yields, 3; harvesting, 2; mechanization, 2;phenology, 1; and analysis and composition, 2.

Between 1960-1979, there have been 119papers published on peanut culture and im-provement.

A collection of approximately 600 cultivars ismaintained at two different locations (Maracayand El Tigre).


The improvement of yields, the easy availabilityof land, a support price sustained by the Govern-ment and the recent introduction of othercrops such as cotton and sorghum for rotationwith peanut, are reasons for the probable ex-pansion of peanut growing in the easternLlanos of Venezuela. This in turn creates anurgent need for more research. The main objec-tives are reducing the cost of the most expen-sive practices of peanut production andresearching the most important aspects ofgenetic and agronomic improvement.

248

Groundnut Product ion, Ut i l izat ion, ResearchProblems and Further Research Needs in Malawi

P. K. Sibale and C. T. Kisyombe*

Malawi is a relatively long and narrow country,which extends some 900 km from North toSouth and 200 km from East to West. It ispositioned along the Great African Rift Valley andthe altitude varies considerably from 50 to3000 m above sea level.

The climate is ideal for groundnut growing inthe altitude range of 200-1500 m and onlyone crop per season is grown during theNovember-May rainy season.

The problems encountered in productionwith this smallholder crop, have mainly been ofan agronomic nature but foliar and soilbornediseases also play an important role in limitingproduction.

Research on groundnuts has been carried outsince the early fifties so that the farmer now haslocally tested research findings to ease most ofthe problem he encounters.

This report reviews some research and pro-duction problems and shows those areas whereachievements have been obtained. It also pin-points problem areas of research which needadditional effort in the future.

Production

Table 1 shows the production during the past 10years (Ministry of Agriculture and Natural Re-sources). Thefigures reflect only thegroundnutpurchases by theAgricultural Development andMarketing Corporation (ADMARC). A lot moregroundnuts are sold and consumed locallywithout reaching ADMARC. Production is ex-pected to rise steeply as a result of directives toextend production of the crop to growers onlarge estates.

* Senior Groundnut Breeder and Senior GroundnutPathologist,respectively, Chitedze Agricultural Re-search Station, P. O. Box 158, Lilongwe, Malawi.

Recommended Cultivars

There are four recommended cultivars — Chalimbana, Mani Pintar, Malimba and RG1. Each is grown in a range of different areas(Fig. 1).

1. Chalimbana. It is a large seeded confec-tionery nut recommended for the plateauareas (altitude range 1000-1500 m). Thisvariety forms the basis of the groundnutexport trade.

2. Mani Pintar. This medium sized red andwhite variegated oil nut, is recommendedfor the lake shore areas (altitude range500-750 m). It originated from Bolivia, isvery adapted to most groundnut growingareas of Malawi and has a comparativelyhigher yield potential than any of therecommended varieties.

3. Malimba. Itis ashortseasoncultivaroftheSpanish type and is recommended for thelow lying hot areas (altitude range 100-300 m).

4. RG1. A medium sized oil/confectionery nutwhich is the recommended variety forThyolo/Mulanje area. It is a locally bredrosette resistant variety.

All the four varieties are susceptible to themajor groundnut diseases which limit produc-tion, except RG1 variety which is resistant tothegroundnut rosette virus.

Uti l izat ion

The main uses of groundnuts are confectionery(of which a large part is exported); oil expres-sion with the residual cake being used as cattlefeed; local consumption in various forms(boiled, roasted etc); and groundnut hay is fedto animals.

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Table 1. Groundnut purchases by ADM ARC (in short tons, 2000 lbs).

Year Southern region Central region Northern region Total

1969 3 352 35 045 2 458 40 8551970 3 741 24 219 1 139 29 0991971 9 500 31000 1 500 42 000 1972 11063 29 588 2 272 42 9231973 8 228 21828 2 899 32 9551974 2638 26 863 2 225 31726

1975 1 967 32 895 1303 36 1651976 1 121 33 248 1 554 35 9231977 456 18 499 1394 20 3491978 516 10 439 1313 12 2681979 1000 21500 1800 24 300a

a. Estimated.

Research and ResearchProblems

The Malawi groundnut improvement programis split into breeding, pathology and agronomysubprograms which reflect the major types ofproblems encountered in groundnut produc-tion. The relationship among the subprogramsis close and fully integrated with one co-ordinator.

The agronomy subprogram has sorted outmost of the questions relating to fertilizer use,spacing and plant population, place ofgroundnuts in rotation, time of planting, har-vesting time, and drying procedures etc. Infor-mation on all these aspects has been passed tofarmers.

Varieta l Improvement

In Malawi it has been achieved by the standardmethods of introduction, selection, and breed-ing.

Introduction has been an effective tool as isevidenced by three of the recommended cul-tivate which have been introduced from abroad— Chalimbana, Mani Pintar and Malimba. Thistool will continue to play an important role inthe future.

Deliberate breeding is now playing a greaterrole in our improvement program. The broadobjective is to develop high yielding varietieswith resistance to the main diseases which limit

production. The RG1 variety, for example, is a product of this work.

Considerable effort is also expended to en-sure that the product is acceptable to the pro-ducer, processor and consumer. Acceptableseed size is an example, and experience hasshown that the producer and the local con-sumer generally are not keen to change to a variety that has kernels markedly smaller thanthose of the Chalimbana variety.

The following are some of the breeding prog-rams that have been undertaken:

Breeding for Kernel Size and Yield

Tables 2 and 3 present some data on seed sizeand yield performance respectively for a re-cently released hybrid (E879/6/4) derived from a cross between Chalimbana and an Americanvariety. This new variety has kernels larger thanthose of Chalimbana and a similar yield po-tential.

Breeding for Disease Resistance

Breeding for rosette resistance has been under-taken in the past and the RG1 variety is a rosetteresistant product from this program. Kernel sizeimprovement of rosette resistant hybrids hasalso been undertaken and several such lines arenow in advanced yield trials.

Breeding for rust resistance has also beenconducted utilizing Tarapoto and the FESR lines

250

as sources of resistance. From our experience,Tarapoto has not been such a useful source ofresistance. Better sources have been acquiredfrom the ICRISAT program and these will befurther utilized in our breeding programs.

Breeding for Cercospora resistance has notbeen undertaken because of the lack of sourcesof resistance from the cultivated tetraploid

Arachis sp. We hope to take advantage of anyuseful material coming out of ICRISAT'sinterspecific work.

We have already acquired some lines reputedto carry resistance to aflatoxin, but no work hasso far been undertaken mostly due to lack ofpersonnel.

The Diallel Selective Mating Program

This is a breeding procedure proposed byJensen to supplement conventional breedingsystems for autogamous crops.

Our program was initiated in 1975 using sixselected parents. Wearenowcarrying differentcomposite hybrid populations in various folialgenerations. A lot of useful variability has beengenerated using this procedure and there areseveral lines showing a lot of promise.

P r o t e c t i o n f r o m Weeds ,D iseases a n d Pes ts

Groundnut protection in Malawi involves thecontrol of weeds, disease and pests in that orderof decreasing importance.

Weed Problems

Several types of grasses are a problem early inthe groundnut growing season—from De-cember to about February. Broadleaved weedsof various types become dominant ingroundnuts later in the season from aboutFebruary to harvest time, which is usually in

Table 2. Seed size of Chalimbana hybrids,1978—79 Mason (mean weighting of100 SMK dried to 7.5% moisture con-tent).

Figure 1. Major areas of groundnut produc-tion in Malawi.

Seed size (g)

Treated with Not treatedDace-nil 2787 with Daconll

Chalimbana 135.4 126.7E8885/1/4A 123.9 117.0E879/6/4 148.7 132.9E879/9/2 123.1 116.7E879/1/2 123.4 112.6E889/6/4 147.1 126.4

251

Table 3. Results of y ie ld t r ia ls f o r the 1977 -78 to 1 9 7 9 - 8 0 seasons, Chitedze (kg/ha) .

1977-78 1978-79 1979-80

a b c a b c a b c

Chalimbana (+) 4141 2950 71 4192 2844 68 3096 2100 68E885/1/4A (+) 5089 3588 71 2822 2074 75 2089 1496 72E879/1/2 (+) 4526 3134 69 3948 2652 67 2918 1987 67E879/6/4 (+) 4941 3459 70 4829 3303 69 2837 1989 71

Chalimbana (-) 4252 2918 69 3407 2474 73 2170 1507 69E885/1/4A(-) 4326 3064 71 2792 1866 67 1970 1437 73E879/1/1 ( - ) 4200 2884 69 3555 2578 73 2185 1507 69E879/6/4 (-) 4785 3321 69 3577 2544 71 2007 1441 73

S.E. ±207.6 ±161.1 ±1.7 ±310.6 ±232.0 ±1.1 ±153.1 ±120.1 ±1.5

CV 8% 9% 4% 15% 16% 3% 11% 13% 4%

a= Unahelled yield (kg/ha); b - Shelled yield (kg/ha); c - Shelling %;(+) - Treated with Daconll; (-) - Not treated.

May and June. Alectra sp is the only wel l -knownand widespread parasitic weed of g roundnut inMalawi .

Handweeding w i th a tradit ional hoe is themost effective method of weed contro l . How-ever, it is a labor demanding and t ime consum-ing method .

Chemical weed contro l w i t h Lasso has beenfound successful against grasses w h e n theherbicide is appl ied to the soi l after the f irstrains.

Handpul l ing is an effective contro l me thod forthe broadleaved weeds and Alectra sp. Thismethod is also labor demand ing and t imeconsuming.

Crop rotat ion has been noted in Malawi to beanother good weed contro l method but i t seemsto be less effective in many cases.

When early weeding and banking cul t ivat ionof the g roundnu t crop have been done atpegging t ime , most subsequent weeds aresmothered by the v igorous g rowth o f t hegroundnut crop.

D i sease P r o b l e m s

The vi rus diseases are rosette and peanut mot -t le v i rus (PMV). Impor tan t fo l iar funga ldiseases wh i ch occur in the m e d i u m al t i tudeareas (1000-1500 m elevation) where it is coo l ,are as fo l l ows in order of decreasing impor-

tance: pepper spot and leaf scorch, Leptos-phaerulina trifolii (Rost) Petr.; early leaf spot,Cercospora arachidicola Hor i . ; g roundnut rust,Puccinia arachidis Speg. ; web blotch, Phoma arachidicola Marasas, Pauer and Boerema; andlate leaf spot, Cercosporidium personatum Berkand Curt. Foliar fungal diseases wh ich occur inthe low al t i tude areas ( f rom 200-1000 m ele-vation above sea level) where it is hot and humid ,in order of decreasing impor tance are: P.arachidis Speg. , C. personatum Berk and Curt,C. arachidicola Hori and L trifolii (Rost) Petr.

Fusarium wi l t caused by Fusarium oxys-porum is a serious soi lborne fungal disease ofgroundnuts in Malawi . I t also causes pod rotsusually when groundnuts are harvested late.

The six possible disease cont ro l me thodsare: varietal cont ro l , e.g., RG1; early p lan t ing ;rotat ion and crop bur ia l ; removal of volunteerplants; good crop husbandry; and fungic idalcontrol of fol iar fungal diseases.

Pest P r o b l e m s

Larvae (caterpillars) of leaf-eating insects arecommon ly found .

The aphid,Aphis craccivora Koch i s thevec to rresponsible fo r t ransmi t t ing the g roundnu trosette virus.

The g roundnu t jassid {Empoasca facialis) is

252

associated with the incidence of the fungaldisease caused by Leptosphaerulina trifolii (Rost) Petr. (Mercer 1977).

White grubs (Eulepida mashona) are larvae ofa beetle. These grubs are soilborne pests whichcause a wilt of groundnuts by damaging theroots.

Cutworms (Agrotis spp) are sometimes a problem, particularly at the seedling stage. Tocontrol pests in general it would not appearpossible to recommend routine spraying ofinsecticides in conjunction with fungicides. Ifserious infestations did occur, the occasionalspray would be worthwhile (Mercer 1975).

Pirimiphos — methyl or carbaryl are used tocontrol leaf-eaters on groundnuts when theyassume destructive proportions. Dimethoate isused to control aphids in order to reduce theirnumbers.


The major groundnut buyers have indicated a growing demand for the large confectionerynuts and Malawi has to aim at satisfying part ofthis demand. The best strategy for Malawiwould be to ensure that yields per unit area ofChalimbana types are maintained, if not im-proved.

Research work has shown that Chalimbanahas a fairly high yield potential if given goodmanagement. However, it is felt that workshould be carried out to raise this yield levelfrom a genetic point of view. Recent researchwork to determine the physiological aspectslimiting yield in Malawi groundnut cultivars hasgiven us some insight into the probable limitingfactors.

ReferencesJENSEN, N. F. 1970. A diallel selective mating system

for cereal breeding. Crop Science 10: 629-635.

MERCER, P. C. 1975. Knapsack spraying of fungicidesto Cercospora (Mycosphaerella) leafspots ofgroundnuts in Malawi. Agricultural Research Coun-cil of Malawi. Occasional Report No. 4.

M ERCER, P. C. 1977. Pests and diseases of groundnutsin Malawi. Pages 483-488 in 1. Virus and foliardiseases. Oleagineux 32.

MINISTRY OF AGRICULTURE AND NATURALRESOURCES — Guide to agricultural production inMalawi 1979-80.

253

Groundnut Product ion, Ut i l izat ion, ResearchProblems and Further Research Needs in Mal i

D. Soumano*

Groundnuts play an important part in Malianagriculture as one of the principal cash crops. Inthe early 1960's groundnuts accounted for 38%of the total value of Malian exports. The share ofgroundnuts in the domestic food economy issizable.

Product ion

A large portion of our arable land is suited togroundnut agriculture, principally in the areaswithin the 500-1400 mm rainfall limits. Withinthat zone, groundnut production varies accord-ing to climate and soil conditions as well ascurrent farming practices.

The principal groundnut production centersin Mali are Kayes, Kenieba, Bafoulabe, Kita,Kolo Kani, Banamba, Koulikoro, Segou, Mani-cepe, San, and Tominian. All of those centersare serviced by an extension agency thatspecializes in groundnut agriculture — theGroundnut and Food Crop Extension Service("L'Operation Arachide et CulturesVivieres" — OACV). Outside of the territory,groundnuts are considered a minor crop.

Groundnut production has fluctuated consider-ably over the past 10 years (1969-1979). It fellduring the period 1960-1967 with exportsplunging from 38 to 16% of the total Malianexportation. The reasons for the productiondrop were twofold; climatic quirks and out-moded production methods.

Malian agriculture in general is farf rom beingfreed from the effects of our uncertain climate.All field crop production was considerably setback in Mali during the drought years of 1969-1974. Plantings were futile due to insufficient ortotally lacking rainfall. Irregular rainfall oftenforces the farmer to replant (if he has leftoverseed stocks) and the plant stands, representing

* Engineer of Agronomic Research, B.P. 258,Bamako, Mali.

several replantings, neither develop nor com-plete maturity in a normal fashion. The yields insuch cases are significantly inferior comparedto normal yield levels.

Proven agronomic practices are seldom ifever adopted in most of our agricultural re-gions. Farming is carried out according to tra-ditional practices in which productivity is verypoor. Extension services, however, have existedfor several years with the aim of extendingimproved farming techniques which can in-crease crop yields. Those improved techniquesthat have been defined by agronomic re-search include animal traction farming, opti-mal planting dates and plant densities, seedtreatment with fungicides and insecticides, useof chemical fertilizers, use of herbicides, theuse of crop rotations which include cash crops,and the careful storage of groundnut harvests.

However, implementation of these ag-ronomic practices has been met with seriousdifficulties in rural areas. It is forthat reason thatour production has little benefited from thosemethods.

Malian groundnut area, production, and yieldin the OACV territory during the past severalyears are shown in Table 1.

Uti l izat ion

Groundnuts are important in the Malian diet.That fact is reflected by the annual per capitagroundnut consumption of 15 kg. They areeaten in a variety of ways: fresh, dried andgrilled, salted, boiled, ground and served withsugar or honey, ground into paste, and used asa sauce base. The last mentioned use is themost common.

Groundnut hulls are ground and used asfuel in two Malian groundnut refineries; SEPONand SEPAMA. At the village level, groundnuthulls are burned and the ashes are used in localsoap and lye production.

254

Table 1. Groundnut area, production, andyield.

Area Production YieldYear (ha) (tonnes) (kg/ha)

1967 46 240 23 600 5101968 48 650 27 855 5721969 71 630 56 655 7901970 102 600 68 507 6671971 92 355 75 185 815

1972 96 000 67 076 6981973 89 660 68319 7611974 107 300 110 300 10201975 170 455 150 000 1130

1976 164 380 160 440 9761977 152 100 102 400 6731978 120 120 100 910 8401979 112 250 85 000 757

Groundnut plants provide an important for-age during the dry season when fresh pasturegrazing is no longer available. With the growinguse of animal traction the use of groundnuts forforage is gaining importance — an example ofthe association of crop and animal agriculture.

In the intensive cultivation areas, groundnutsprovide a substantial source of income for thefarmers. The commercial market is partly ex-ported (by SOMIEX) and partly processed bythe two Malian processors SEPOM and SEPAMA.Groundnut processing provides culinary oil,and meal. Groundnut meal is used in animalfeed mixtures at the National Large AnimalResearch Center (CNRZ and the Poultry Centerat Sotuba (CAS).

The population of Mali exceeds 6 million andis growing steadily. It is evident that the do-mestic needs of groundnuts and groundnut by-products are far from being met. It is for thatreason that we look for ways through researchto increase groundnut production. Table 2 shows production and end uses of Maliangroundnuts.

Research Problems andFuture Research Direct ions

We cannot expect to find clear-cut solutions toproblems affecting an increase in groundnut

255

production. We must define the parameters andlet the solutions evolve over time.

We have outlined the following areas ofresearch concentration in groundnuts:

1. Cultivars. There should be an ongoingsearch for cultivars adapted to particularrainfall zones and soil types. The principalselection criteria should be yield, flower-ing cycle in harmony with rainfall cycle,plants adapted to mechanization, diseaseresistance, and food technology consider-ations like grain size, oil content, etc.

2. Agronomic techniques. We must identi-fy optimal planting dates; soil prepa-ration methods, plant densities, timingof fertilizer applications, and storagetechniques.

3. Chemical fertilizers. We must determineoptimal economic returns under intensivecultivation situations.

4. Pesticides. We must find optimal dosagesand formulations of fungicides and insec-ticides.

5. Chemical herbicides. We must find themost economically feasible and agronomi-cally effective formulations.

6. General agronomy. We must accelerateresearch of rhizobial inoculations andgrowth regulation.

7. The use of groundnut hay for feed totraction animals.

8. Quality control of groundnut — particularly aflatoxin detection and con-trol.

Additionally we must consider the liaisonbetween our research and the extension of ourresearch. The following play a part in thatbridge: the maintenance of foundation seedstocks of released varieties, the quality controlof seed increase fields, the measure of qualitycontrol for marketing industrial groundnuts, the

definition of quality standards for confectionerygroundnuts, and quality sampling of exportedgrain lots.

The above mentioned research themes havealready been outlined in our 5 year MalianResearch Plan. Already our research structureshave addressed themselves to these questionsfor several years with the following concreteresults:

1. The release of five commercial varietieswhich are already at the farmer level — 28-206, 47-10, 59-127, 55-437, GH-119-20.

2. Optimal soil preparation techniques whichconsist of plowing in zones above 900 mmrainfall and harrowing operations in areaslower than 900 mm rainfall.

3. The early planting of late maturing va-rieties with plant spacings of 0.6 x 0.15 m for late varieties and 0.4 x 0.15 m for earlyvarieties.

4. Recommended seed treatment is a mix-ture of 25% thiram, 25% heptachlor and25% autraquinone.

5. Chemical fertilizer is recommended at 65kg/ha superphosphate (21% P2O5). Thisdose is considered economically efficient.Higher doses are now being consideredfor groundnut-cereal rotations.

6. Different herbicides are now being consi-dered. The most promising herbicide isgerathene (CIBA Geigy) which is alreadybeing used at the farmer level.

These research results have been promisingand over time they will be defined to fit chang-ing situations.

This summary reports the state of the art ofapplied groundnut research in Mali and whichwe find necessary in order to intensifygroundnut production. Still and all, we need tofurther mobilize human and financial resourcesto achieve our goal.

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in Mozambique

A. D. Mal i thano*

Product ion

Mozambique has a surface area of 79.9 millionhectares of which only 18.8% is used for agricul-ture. Unoccupied land which can be used foragriculture occupies about 52.9 million ha.

In 1969, 155 000 ha of groundnut were esti-mated to be planted representing 3.5% of thetotal area under cultivation and makinggroundnuts the fifth crop in importance in termsof area (Missao de Inquerito Agricola-MIA1969).

The production suitability of the groundnutareas depends on the rainfall and soil type(Almeida 1968). In the areas that are rela-tively dry and have an erratic and shortduration rainfall, e.g., the southern region with600-800 mm/yr, early maturing varieties ofgroundnuts are recommended. In the centraland northern regions with 800-1200 mm/yr,late maturing varieties are grown. Areas withheavy clay, black, gray and compact soils werenot considered for groundnut production.

Most of the groundnuts are produced in thecoastal area, especially in the provinces ofNampula, Inhambane, Zambezia, Maputo andGaza.

Table 1 summarizes the number of farmers,hectarage and yield in specified years. In 1970,farmer numbers doubled and hectarage in-creased, butyield was very low. Since then yieldhas continued to decrease and today there is a critical groundnut shortage.

Y i e l d

The average is very low and ranges from 266 to521 kg/ha. The main causes are unimproved

* Advisor, Groundnut Improvement Project, Univer-sity Eduardo Mondlane, Maputo, Mozambique.

varieties, traditional production methods, noruse of fertilizers, and diseases. About 99% ofthe groundnut area is cultivated by the localpopulation on traditional farm units averagingabout 0.34 ha.

Varieties

Recommendations for the northern region wereSpanish, 48/21, Namarroi and Fumo; for thecentral region Paulista, White Spanish andBombay; and for the southern region NatalCommon and Valencia, according to Almeida(1968), Sousa (1971) and Milheiro and Rod-rigues (1973), respectively. Southern region rec-ommendations based on data obtained fromUmbeluzi Agricultural Experimental Stationmay be invalid as the station soils are notrepresentative of the groundnut growing areas.

The above recommendations were not ac-companied by an effective seed multiplicationand distribution program. The small farmersplanted their own seed resulting in mixtures ofearly and late maturing types which causeddifficulties at harvest and depressed yield.

C r o p H u s b a n d r y

Improved varieties alone will not make anappreciable increase in yield. If culturalmethods were improved, yields could be in-creased considerably. Therefore, much effortshould be made by extension services to im-prove crop husbandry, but because these ser-vices are inadequate and inefficient the prob-lem still continues.

Mixed cropping is practiced and groundnutsare nearly always intercropped with maize,cassava, sorghum, millet and plantation cropssuch as coconut palm and cashew (Malithano1979, unpublished; Malithano and van Leeuwen1980). When interplanted, groundnut density is

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very low. It is also low when groundnut is grownas a pure crop (Malithano 1979, unpublished).Thus mixed cropping and low planting densityas practiced by farmers in Mozambique ad-versely affect groundnut yield.

Soil preparation varies from zero tillage toadequate seedbed preparation. The hoe isthe main tool for all types of cultivation. Veryfew farmers use ox-drawn plows. Manygroundnut farm units are very small becausethe farmer cannot prepare a large piece of landbefore the rains by using a hoe only. Therefore,inadequate land preparation, inefficient farmtools and small farm units minimize the quan-tity of groundnuts that can be produced.

Late planting, e.g., after the planting rains, iscommon because the land is not ready for sow-ing at the beginning of the rains. Milheiro(1962)in northern Mozambique has shown that lateplanting reduces yield because the number ofplants attacked by groundnut rosette virus in-creases with the delay in planting. When plant-ing was delayed until January, nearly all theplants were attacked by rosette and the yieldwas very low.

D iseases

Important diseases such as rosette and leaf spotcaused by Cercospora arachidicola Hori andCercosporidium personatum (Berk. & Curt.)Deighton are endemic to Mozambique andcause great yield losses. Another important disease is rust caused by Puccinia arachidis Speg. Many other minor diseases also occur.

Fe r t i l i ze r s

They have not been used by small farmers.

Experiments carried out at Mocuba and Um-beluzi in northern and southern Mozambique,respectively, did not support their use (Almeida1968). Most groundnut production soils insouthern Mozambique are sandy and very poorin mineral nutrients. Correct use of fertilizerswill boost yield.

N a t u r a l Hazards

In 1976 and 1977 a large part of the crop in thesouth was destroyed by the off-season rainswhich came at harvesting time. Also from1975-1980, rains have been erratic and unpre-dictable causing planting delays. Prolongeddroughts over the past two seasons have com-pletely damaged the crop in the south.

In many southern areas the consecutive cropfailures have caused groundnuts to completelydisappear from the local market in the last fouryears. Many farmers do not have the seedandthisalonewill greatly reduce the area undergroundnuts in 1980, with a consequent reduc-tion in total yield.

The Government is very much concernedwith this drastic reduction in production be-cause of its effect on the economy and its far-reaching social consequences, especially in thesouthern region where, as a food crop, itsscarcity is keenly felt

S e e d I m p o r t a t i o n

Two varieties, Starr and Tamnut 74 of shortvegetative cycle and early maturity were im-ported by the Government in large quantities in1977 from USA for multiplication and distribu-tion to farmers in the southern region. In 1979,variety Manipintar was imported from Malawiand the varieties Makulu Red, Mwitundeand Malimba were supplied by the InstituteNacional de Ivestigacao Agronomico (INIA).

Seed Multiplication

It is carried out by the National Seed Company(NSC), administered by the Ministry of Agricul-ture. The Company is a joint venture between theGovernment of Mozambique and Nordic coun-tries. Its staff are recruited by FAO and theSwedish International Development Authority(SIDA). The multiplication of Starr and Tamnut74 started in 1978 and that of Manipintar, Makulu

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Source: Missao de Inquerto Agrlcola de Mocambique 1968,1969, and 1970.

Table 1. Groundnut termors, areaproduct ion, 1961-1970 .

• o w n , and

Year No. of farmersArea sown

(ha)Production

(tonnes)

1961-67196819691970

46\1431434 466413 583936 338

155 372126 159230 722253 817

64 7775681680 89455 186

Red, Mwitunde, and Malimba in 1979. Statefarms are the main centers of multiplication.Some cooperatives, agricultural research sta-tions and training centers are also involved.

Uti l izat ion

Most of the produce is consumed as food andonly a small percentage is industrialized. Forhuman consumption, groundnuts may becrushed for oil, and to flavor vegetables, meatand fish, or be eaten directly. Woodroff (1973)gives a detailed account of the uses ofgroundnuts.

G r o u n d n u t O i l

Local consumption of groundnut oil as cookingoil is very high. The oil is used in cooking meat,fish, vegetables and rice. Small quantities arealso used in seasoning salad.

Food F l a v o r i n g

Groundnut flour is added to meat, fish, vegeta-bles, cassava and sweet potatoes after theyhave been cooked sufficiently. The food isserved after it has simmered for some time toallow the groundnut flour to cook.

Groundnut milk is used in chicken, meat andfish curries. The milk is obtained by putting finegroundnut flour in a sieve and mixing with wa-ter. The extract is then added to the food.

Groudnut curry sauce is a favorite dish whichis prepared by using very fine groundnut pow-der in a water suspension. It is added to friedtomatoes and onion, allowed to simmer andthen served with rice.

D i r e c t C o n s u m p t i o n

Fresh boiled groundnuts are widely consumed.They are cooked in the shell and served. Topreserve them, the cooked groundnuts aredried in the shell, stored and served as required.

Groundnuts may also be consumed fresh orafter drying, but quantities eaten in this way areusually small as they are not very appetizing.

On large farms, laborers were served boiledgroundnuts with upsa, a thick maize flour por-ridge.

Small quantities of groundnuts are con-

sumed roasted either in the shell or as a kernel.

Research Problems

The Institute Nacional de InvestigacaoAgronomico (INIA), of the Ministry of Agricul-ture is responsible for and coordinates all ag-ricultural research in Mozambique. Other or-ganizations, outside the Ministry of Agriculture,which are involved in research collaborate withINIA that provides infrastructures such asresearch stations, farm machinery, transport,fertilizers, insecticides, etc. It is within thisframework that the Faculty of Agriculture, Uni-versity Eduardo Mondlane in Maputo is con-ducting research on groundnuts. Maputo islocated in a very suitable area for groundnutwork.

Groundnut is one of the crops that wasneglected during the colonial era when verylittle research was conducted on this crop. Theresult has been that cultural practices haveremained unimproved and very little informa-tion is available on varieties adapted to differentecological zones of the country. Adapted, purevarieties for use by farmers do not exist.

Under thesecircumstances it is reasonable tosuggest that in Mozambique research muststart afresh and should encompass all aspectsof production such as variety trials, plantdensity, date of planting, cultural practices, cropprotection, fertilizer requirements and soiltypes. Acquisition of local and exoticgermplasm together with breeding should bean integral part of the research.

ObjectivesThe objectives of research are the identificationof high-yielding varieties adapted to differentecological zones of the country for use by com-mercial and small farmers, and the improvementof cultural methods. These objectives cannot berealized immediately asthere are many interact-ing factors requiring both short and long-termsolutions.

S h o r t - t e r m O b j e c t i v e s

The most urgent and immediate need is toprovide the farmer with seed of groundnuts.This may be achieved by importation of

259

groundnuts with specific agronomic charac-teristics from those parts of the world that haveclimatic conditions similar to Mozambique. Al-ready Starr, Tamnut 74, Manipintar, MalimbaMwitunde and Makulu Red have been im-ported.

The Faculty of Agriculture, UniversityEduardo Mondlane, has maintained and multi-plied some cultivars previously grown inMozambique and has acquired other exotic vari-eties from different parts of the world. Most ofthese cultivars are being evaluated for yield anddisease resistance. Those varieties that performwell over years and across sites will be multi-plied and distributed to farmers.

Some cultivars in the Faculty collection carrytraits such as resistance to rust, rosette anddrought.

Surveys have been conducted to study theexisting cultural practices used by the smallfarmers (Malithano 1979, unpublished). Thisinformation is useful in order to plan a realisticgroundnut improvement program includingintercropping.

Long-term ObjectivesA major objective is the breeding of high-yielding varieties resistant to diseases andpests, and adapted to the local conditions ofcrop production. As industrial processing ofgroundnuts for oil and animal feeding willbecome increasingly important, there is need tobreed and select varieties with a high oil andprotein content.

In order to achieve these objectives it isnecessary to assemble a large germplasmmade up of both local and exotic material.Some of those collections that have specifictraits can be used for hybridization in order toincorporate desirable genes in some cultivarswith proven performance.

Cultivars and breeding lines have been re-ceived from ICRISAT, FAO, USA, and severalAfrican countries. A local germplasm expedi-tion took place in Southern Mozambique earlyin 1980 and another one has been planned for1981 in collaboration with the InternationalBoard for Plant Genetic Resources (IBPGR) tocollect groundnuts from the central and north-ern regions of Mozambique.

Other aspects of research to be studied thataffect yield are cropping systems, cultural prac-

tices, fertilizer trials, plant density and date ofplanting.

As Mozambique is endowed with water re-sources, irrigation of groundnuts will becomeimportant and research in this direction shouldbe initiated. Irrigation is particularly importantbecause dryland farming of groundnuts is sub-ject to great variation in yields making it difficultto predict production. In Zimbabwe, irrigationof groundnuts is becoming increasingly popu-lar because of the high yield obtained by farm-ers (Hutchinson 1980).

In order to remove the drudgery of using a hoe as a tool for all farm operations, a seriousstudy on the mechanization of production todevelop simple tools for small farmers is mer-ited. Animal-drawn plows, seed planters andharvesters will facilitate the work of the farmerand will enable him to expand the area underproduction.

Research is required to identify cultivars thatnodulate readily in virgin soils as well as in soilswhere groundnuts are currently grown. As fer-tilizer prices continue to rise, nitrogen fixationstudies will become increasingly important.


There are many problems associated withgroundnut research such as lack of trainedmanpower, research stations not suited togroundnut work, quarantine of exotic acces-sions, and storage facilities, to mention only a few.

Lack of trained personnel is serious. In orderto have an interdisciplinary approach, an ag-ronomist and a plant pathologist are requiredimmediately. Currently, an agronomist is beingrecruited.

Field assistants and technicians are lacking.ICRISAT has been contacted to train one fieldassistant and two technicians.

There is a need to identify locations suitablefor groundnut work. The choice of Umbeluziand Ricatia research stations, for instance, wasbased on needs to conduct research on cropsother than groundnuts.

As the importation of exotic germplasm in-creases so will the dangers of introducing newdiseases become more serious. Thus, stafftrained in quarantine will be of great value toour future work.

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The new introduct ions wi l l need to beevaluated, documented and stored. At the mo-ment there are no proper storage facil i t ies foreither short or long- term storage. There aresome funds to buy a cold room for stor ingbreeding stocks, but the equipment has not yetbeen purchased.

ReferencesALMEIDA, F. SOUSA, 1968. A cultura do amendoim em

Mocambique Louren co Marques. Instituto deInves-tigacfio Agronomico de Mocambique. Com-unicacoes No. 15.

HUTCHINSON G. 1980. Groundnut increase. The Farmer50(48): 39.

MALITHANO, A. D., and VAN LEEUWEN, J. 1980.

Groundnut-maize interplant ing in southernMozambique. International Second Symposium on

Intercropping for the Semi-Arid Areas, Morogoro,Tanzania, 4-7 Aug 1980.

MILHEIRO.A. D. 1962. A cultura do amendoim; ensaiosde variedades e datas de sementeira. Gazeta doAgricultor XIV(153): 37-41.

MILHEIRO, A. D., and RODRIGUES, A. F. 1973. Valor

comparativo de algumas variedades de amendoim.Agronomico Mocambicano 7(1): 1-64.

MlSSAO DE INQUERITO AGRICOLA DE MOCAMBIQUE.

Estatlsticas Agricolas de Mozambique 1969 and1970.

Sous A, C. V. 1971. Algumas caracteristicas de culti-vares de amendoim experimentados em Mozam-bique. Agronomico Mogambicano LourengoMarques 5(2): 117-123.

WOODROFF, J. G. 1973. Peanuts: production, proces-sing, products. 2nd ed. Westport, Connecticut, USA:Avi Publishing.

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Groundnut Product ion, Research and ResearchProblems in Niger

A. Mounkai la*

Product ion

Before the 1973 drought, groundnut rankedthird in production after millet among the fivemajor crops of Niger (Table 1). Cultivation ofgroundnut in the pre-1973 years had beenencouraged by the presence of a marketingcorporation (SONARA), three shelling millswith a capacity of 82 000 tonnes, and three oilrefineries for exporting crude oil with a totalprocessing capacity of 105 000 t of shelledgroundnuts. This resulted in the area plantedincreasing from 325 000 to 383 000 ha between1960-68 and 1969-73.

The 1973 drought and the rosette epidemic in1975 led to a dramatic decrease in the cultivatedarea and production (Table 1), with a sub-sequent failure of the marketing corporation,and the shelling mills and refineries. While thepercentage of groundnut in Niger's exports was45% in 1972, it declined to 24% in 1973, and fellto 5% in 1975.

In 1977 the shelling mills at Dosso andTchadoua operated at 8.5% and 3.2% of theirtotal capacity, respectively, and the OilRefineries Society of Niger of Matamey andSiconiger could only use 19% and 9.5% of theprocessing capacity. The national productionprovided only 7.4% of the crushing potential ofNiger.

To rectify this deteriorating situation, Nigeradopted a policy to improve production via twoincentives: technical (improved land use, fer-tilizers, and use of selected seeds) and financial(establishment of finance corporations and in-creased prices to farmers).

The following production targets (shelledgroundnuts) were established: 1979 (80 0001);1980 (88-0001); 1981 (96 0001), 1982 (106 0001)and 1983 (120 0001). To date, these targets arebeing achieved.

* Section Arscnide, CNRATarna, BP 240, Maradi,Niger.

Groundnut Research in Niger

Until 1974, research was focused on compara-tive trials of introduced and promoted varieties,and of cropping techniques.

Since 1975, the National Institute of Agricul-tural Research of Niger (INRAN) has addedother research programs which include foun-dation seed production, groundnut breeding andimprovement through hybridization, and culti-vation under irrigated conditions.

V a r i e t a l T r i a l s a n d I r r i g a t e dG r o u n d n u t C r o p s

The objective of this program is to identifyexotic varieties that are best suited to thecropping conditions in Niger and are superior tothe varieties already promoted in the country.This is a very old program which rose inimportance in 1976. Since then, more than 200varieties have been introduced from theneighboring countries (Senegal, Upper Volta,Nigeria, etc.) and the United States.

Each year the best varieties are tested accord-ing to thefollowing classes: early varieties (lessthan 90 days); late varieties (more than 90days); early rosette-resistant varieties; and laterosette-resistant varieties.

Fertilizer, insecticide, and fungicide trialshave accompanied these varietal tests.

Since the objective is to increase groundnutproductivity in this arid country, varietal trialswere also conducted under irrigated conditions(off-season trials) in order to determine thebest varieties and the best period during theyear.for growing groundnut. In 1979 the highestyield of 5 t/ha was reached with the variety 796.

F o u n d a t i o n Seed P r o d u c t i o n

This program was started in 1975 with theobjective of providing foundation seed with a

262

Table 1. Groundnut production in Nigar from 1968 to 1979 (000 tonnas).

Crop 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978

Millet 733 1035 871 958 919 627 883 581 1019 1130 1123Sorghum 301 388 230 267 208 126 219 254 286 334 371Cowpea 74 160 84 72 124 92 133 218 216 207 271Rice 39 39 37 27 32 46 30 29 29 27 32Groundnut 270a 270a 205 257 260 77 129 42 79 90 74

a. Average of production in 1967, 1968, and 1969.

high degree of purity. Modern facilities andequipment are used for conducting the experi-ments and supplemental irrigation is given tocrops when there is deficit rainfall.

Each year seeds of promoted varieties(55-437,47-16,28-206) and introduced varietiessuch as TS 3-1, are produced in sufficientquantities for supplying material to seed multi-plication centers. Yields under these conditionscan reach 1000 kg/ha after winnowing. Theseseeds are produced in an area exceeding100 ha.

G r o u n d n u t B r e e d i n ga n d I m p r o v e m e n t

A crossi ng prog ram was sta rted i n 1976 with theobjective of producing varieties having thefollowing qualities: productivity, earliness,rosette resistance, rust resistance, and withdesirable agronomic and industrial characteris-

tics. The most advanced lines were at the F7stage in June 1980.

Agr icu l tura l Research Problems

As a consequence of the 1973 drought, Nigerhas given priority to the cultivation of cashcrops, and now groundnut ranks only fourth intotal tonnes of crop production. This policydoes not favor investment in groundnut re-search.

Although research has made some achieve-ments, there is an inadequacy in the transfer oftechnology from research stations to farmers'fields. It is a problem causing considerableconcern amongst research scientists.

A further problem relates to scientists beingisolated from other groundnut workers in res-pect of inadequate travel, difficulties in pub-lishing scientific findings and also receivingpublications from other scientists.

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Groundnut Product ion, Ut i l i za t ion, ResearchProblems and Further Research Needs in Nigeria

S. M. Misar i , C. Harkness and A. M. Fowler*

Product ion

Groundnut is one of the most popularly culti-vated commercial crops in Nigeria with the bulkbeing grown in the northern states (Figs. 1, 2).The southern states produced only 1% of thetotal output in 1970-71 (Agboola 1979). TheSudan Savanna Zone (particularly in areas ofless than 1016 mm of annual rainfall) hasoptimum groundnut producing conditions.

Product ion Stat is t ics

In Nigeria, they can be very misleading andalmost invariably underestimated. Produc-tion estimates have been based mainly onpurchases by the marketing boards (MB), ex-ports from Nigeria and imports of the recipientcountries. Such figures underestimate produc-tion since primary producers retain unspecifiedamounts for consumption and for planting inthe next season, engage in crude oil processing,sell outside the MB system or smuggle abroadwhere businessmen take advantage of the pricedifferential between Nigeria and her neighbors.The estimates of groundnut production that issold to the MBs, for instance, range from 33 to50% of the total production (Fetuga and Ogun-fowora 1976).

A downward trend in groundnut productionin Nigeria has been caused by several inter-related factors such as low producer prices, lessfarm labor due to rural population movementsto the cities, the drought years of 1971-73, theunprecedented rosette virus epidemic in 1975,an increasing incidence of rust, and higherprices for guinea corn.

* Entomologist, Plant Breeder and Plant Pathologistrespectively, Institute for Agricultural Research,Ahmadu Bellow University, PMB 1044, Zaria,Nigeria.

The fall in groundnut production has con-tinued despite an increase in guaranteed pro-ducer price from N 68 per metric ton of kernelsin 1966-67 to N350 perm, ton in 1979-80. Thepurchasing power of N 68 in the mid 1960's isalso probably more than that of the currentproducer price of ft 350. The Central Bank ofNigeria (1974) estimated that while the pro-ducers' income for cotton in the Sudan andSahelian Zones declined from N 12.4 million toN 11.5 million between 1970-71 and 1973-74,thatfor groundnuts went from N19.2 million toN 4.1 million.

These and other factors are enough challengefor Nigerian scientists to look into the problemsaffecting groundnut production.

Product ion Areas

Groundnut growing has declined sharply in theold major producing areas north of latitude12°N. During the 1970's there have been cropfailures in many places due to dry weather andother causes.

In the sixties it was generally considered that33-50% of the national crop came from KanoState. It is very evident now that groundnuts nolonger produce well in the northern parts of thestate and have more or less gone out of cultiva-tion over extensive areas. A similar situationhas arisen in other parts of the Sudan Savanna— Katsina, Daura, Azare, Nguru and Gashua,due basically to less favorable rainfall now thanduring the sixties and the decades back to the1920's. As a result of this, the major centers ofproduction of the sixties no longer exist.

In the northern and southern Guinea Savan-nas, where rainfall is adequate for groundnuts,there are other considerations:

1. Farmers may not regard groundnuts asimportant and are inexperienced with thecrop.

2. The soft sandy soils of the Sudan Savanna

264

allow easy harvesting even when dry.Heavier soils further south can set hardand make harvesting extremely difficult.

3. Late rain frequently damages harvestedgroundnuts, and drying can be a problem.

Some changes which could be made to en-

courage groundnut farmers are mechanization;improved seed; crop protection; fertilizer use;cropping systems, including intercropping;supplementary irr igation on rainfedgroundnuts in northern irrigation areas; andchange in production areas. There is consider-

Figure 1. Groundnut producing areas and mean annual rainfall, Nigeria.

265

able scope for sound extension work in areaswhere groundnuts have not been traditionallyimportant.

A project was carried out in 1976 and 1977 atHunkuyi (Zaria), with about 50 farmers whowere interested in growing groundnuts. Theywere provided with advice and seed, fertilizer,and seed dressing. Production varies fromabout 400 kg/ha pods to 3000 kg/ha. Growers

were pleased with the results and with them-selves.

Uti l izat ion

The groundnut is cultivated for kernels, the oilderived from them, and hay for livestock feed.

The seeds contain about 50% (45-56%)

Figure 2. Land use for groundnuts.

266

non-drying oil and about 30% (25-34%) pro-tein. Because of its very high calorie content,groundnut is one of the most concentrated foodproducts. The importance of groundnuts in theNigerian diet cannot be underestimated, con-sidering the inadequate protein in such diets.

Five percent (Olayide et al. 1972) of theestimated 58.9 grams of crude protein availableper head per day in Nigeria (Abalu 1978) iscontributed by groundnuts. Considering thatthe estimated minimum daily requirement isabout 65 g of protein (Olayide et al. 1972),increased groundnut production can helpeliminate this protein deficiency.

The groundnut is widely consumed inNigeria. Oyenuga (1968) has discussed the vari-ous uses of groundnut and its by-products. Thekernels can be eaten fresh, boiled, dry orroasted. Most are crushed for oil and the re-sidual cake is rich in protein and providesvaluable human and livestock food. Groundnutflour can be made by milling the cake and this isused as an ingredient in soups, stews, sauces,

Figure 3. Uses of groundnuts (Oyenuga 1968).

sweets, confectioneries, puddings and bakeryproducts.

The most valuable product is the edible oilwhich comprises 50% of the total kernel. It isused for cooking, especially in northernNigeria. Other uses are for lighting, a basis ofpomade, soaps and cosmetics, salad oil, and inthe manufacture of margarine.

The husks find some use as a fertilizer and soi I conditioner. They are also used as litter forlivestock and as an absorbent in livestock feed.Industrial uses include production of pressboard and insulating materials.

The haulms from which the pods have beenpicked, are a valuable livestock feed in northernNigeria.

Oyenuga (1968) has summarized most of thepossible uses of groundnut (Fig. 3).

Before the petroleum oil boom, groundnutwas one of the major sources of revenue andforeign exchange. Most groundnut farmersgrow groundnuts in order to sell them for cashto pay their income tax.

267

Research Problems

Pests

Groundnut is attacked by invertebrate pests anddiseases at all stages of crop development andalso during storage. Because groundnuts in thepast were considered to be free from any majorinsect problems (Misari and Raheja 1976), re-search emphasis was placed only on the rosettevirus (GRV) and its vector Aphis craccivora Koch. Although GRV is still a major threat to theindustry a comprehensive report on pests at-tacking groundnuts in northern Nigeria (Misari1975; Misari and Raheja 1976) has revealed theoccurrence and diversity of the other major andminor arthropod pests of the crop.

All parts of the plant at all growth stages aresubject to attack by pests. There are soil, aerial,postharvest, and storage pests.

Soil Pests

Groundnuts are subject to attack by two majorsoil pests — millipedes and termites — andthree minor pests — white grubs, lepidopter-ous larvae and nematodes.

Thereare more than five species of millipedespresent; the most important is Peridontopyge spinosissima Silvestri (Odontopygidae: Spiros-treptida) (Misari 1975). The estimated yield lossdue to millipedes varies from place to place andfrom year to year (Johnson 1978; Misari 1974;Raheja 1975).The figures range from 1 to 39%but these are an underestimate of thetotal damage since the very immature podswere not examined in some cases.

Termites constitute one of the most impor-tant subterranean pests of groundnuts inNigeria. Sands (1962 a, b) recorded damage togroundnuts, and the symptoms he describedwere similar to those found by Perry (1967).

Most of the damage and loss are caused by theubiquitous small fungus grower (Macroter-mitinae) belonging to the genus Microtermes (Perry 1967; Johnson et al. 1978; Wood et al.1977). Populations in excess of 4000 termites/M2 have been recorded in Nigerian agro-ecosystems (Wood et al. 1977). M. subhyalinus Silvestri has been identified as one of theimportant species (Perry 1967).

Amitermes evuncifer and Odontotermes spp

are other termites attacking groundnuts inNigeria.

Unidentified species of lepidopterous larvae(Perry 1967; Johnson 1978) and white grubs(Scarabaeidae) have been observed to attackgroundnut but they are important only inlocalized areas.

To date, nematodes have not been incrimi-nated as economically significant pests ongroundnut in Nigeria. Only two species appearto be potentially important. The groundnut-podnematode, Pratylenchus brachyurus, also cal-led the lesion nematode, can kill young seed-lings. A species of Ditylenchus has also beenreported as attacking pods but always at verylow incidence. Bos (1977) described a newspecies called the seed testa nematode,Aphelenchoides arachidis (Bos).

Over eleven nematode species have beenfound associated with groundnuts includingHelicotylenchus dihystera, Scutellonema clath-ricaudatum, Creconemoides spp, andPratylenchus zea.

Aerial Pests

Of the more than 70 insect species associatedwith the groundnut crop in northern Nigeria(Misari and Raheja 1976) only a few are thoughtto be economically or potentially serious asshoot and foliage pests. These include thecowpea or groundnut aphid, Aphis craccivora Koch; several species of cicadellid leafhoppersnotably the cotton jassids, Empoasca dolichi Paoli and Jacobiella fascialis Jac; thegroundnut leaf beetles, Monolepta spp; andLuperoides quaternus Frm; and to a consider-able extent flower feeding blister beetles andthrips also becoming more important.

APHIS CRACCIVORA KOCH AND THE ROSETTE

VIRUS. This is the most important pest in thiscategory. It is a sap feeder and although a heavyattack can result in wilting and death of the cropespecially in hot weather, it is a more seriouspest as the vector of the groundnut rosette virus(Zimmerman 1907; Storey and Bottomley1925).

The groundnut rosette virus disease and itsaphid vector, A. craccivora have been reportedin Nigeria for over 50 years (Harkness 1977). Thedisease symptoms in Nigeria (Rossel 1977) aresimilar to those described in other countries butthe form of rosette most commonly found in

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Nigeria is the "green rosette." Symptoms arevariable but a downward and inward rolling ofthe leaf margins is highly characteristic of thegreen rosette (Harkness 1977). The chloroticrosette form is of rare occurrence and is charac-terized by bright yellow to white interveinalchlorosis, crinkling, twisting and stunting of thefoliage and shoots.

In 1957, research work on the aphid/rosetteproblem began in Mokwa. Here, A' Brook (1964,1968) showed that early planting and closespacing achieved control of rosette disease.Booker (1963) reported similar findings inSamaru.

The rosette epiphytotic in 1975 was the worstrecorded in the history of groundnut productionin Nigeria. It destroyed about 0.7 million hect-ares of groundnuts in the Sudan and northernGuinea Savannas and so revealed the vulner-ability of the total crop and the need for resis-tance (Yayocketal. 1976). Because an estimated80% of the national groundnut productionmay come from these zones and nearly allthe remainder comes from the southern GuineaSavanna (Harkness et al. 1971), the need forintensive research into the causes and controlof the rosette disease cannot be over-emphasized.

CAUSES OF THE 1975 ROSETTE EPIDEMIC. It is still

not fully understood why the 1975 epidemicoccurred (Yayock et al. 1976, 1978; Akinfewa1978) but some or all of the following factorsmay have been responsible:

1. Research efforts on rosette-resistant va-rieties had been concentrated for theriverine areas where rosette consistentlycaused more significant losses than in thenorth. While the current recommendedresistant varieties (M25.68 and ex-Bambey69-101) arelong season and most suitablefor the riverine areas, those grown in thenorth are short season and less resistant.

2. Aphid populations and the number ofprimary rosette infection loci were ex-traordinarily high in both the epidemicregions of the main groundnut productionarea in the north and the riverine areas inthe south where no epidemics occurred.Since crop seasons in Nigeria are depen-dent upon the rains which move as a beltup and down with the intertropical discon-tinuity (ITO), Feakin (1967) postulated that

rosette and its vector could move over thegroundnut growing areas with the prevail-ing rain bearing southwest to northeastmonsoon winds (Fig. 1). Benoit(1977) hascomputed the advance of rainy season atvarious latitudes in northern Nigeria.

3. Earlier widespread groundnut plantingstook place in riverine areas together withsporadic plantings in the north. As therains permitted, early plantings continuedin the north so that by mid-May there was a spread of groundnuts of various ages fromsouth to north. This led to an early disper-sal of aphids and the virus from south tonorth. A secondary spread of the virusthen overwhelmed thecrop over extensiveareas.

4. The mild dry season and early rainfall mayhave assisted the carry-over of rosetteinfected groundnuts, especially in thefadama and irrigation areas of the north-ern groundnut growing areas. The occur-rence of abnormally long periods ofdrought in many areas just afteremergence of the groundnut crop en-hanced the build-up and dispersal of aphidcolonies. This may have led to a zonalbuild-up of rosette virus reservoirs (Rossel1977) and a rapid secondary spread of thevirus disease.

The role of weather in the epidemiology andpopulation dynamics of the virus and the aphidsis being investigated.

APHID AND ROSETTE PROBLEMS IN NIGERIA. Al-

though virus material collected in Nigeria hasbeen studied in England, by Okusanya andWatson (1966) who confirmed its identity asgroundnut rosette virus, little is known of theproperties of the causal virus or viruses. Hulland Adams (1968) and Okusanya and Watson(1966) found that isolates from East Africa andfrom Nigeria are sap transmissible.

Their host range and vector studies revealedtwo components — a symptom inducing com-ponent (GRV) being sap transmissible and a symptomless component, being aphid trans-missible only. The sap transmissible compo-nent was found to be aphid transmitted onlywhen in combination with the symptomlesscomponent, and hence the designation of thelatter as groundnut rosette assistor virus(GRAV) (Hull and Adams 1968).

269

It is not known if the two-component nature ofthis virus plays a significant role in theepidemiology of the disease.

All efforts to find natural off-season hosts(other than groundnuts) of the virus have failed.Since the virus is not seed transmissible, andsince the groundnut crop is only of rare occur-rence during the dry season, work still continuesin search of the carry-over mechanism of thevirus from one season to another. Akinfewa(1977) has tentatively identified the rosette vec-tor, A craccivora on over 60 wild and cultivatedplant species in ten families. About 24 of thesespecies (15 wild and 9 cultivated) belong to thegroundnut family Papilionaceae.

Since the majority of the wild hosts andgroundnut volunteers are found in fadamaareas and irrigation sites of the northern states,it appears thatthe hypothesis of a south to northmovement of virus/vector complex has to bereviewed.

Recent observations have shown an increas-ing prevalence of the chlorotic rosette in addi-tion to the usual green rosette. Some virus-vec-tor relationships of the green rosette fromNigeria and the chlorotic rosette from EastAfrica were studied in England by Okusanya(1965). Her work showed that a Nigerian race ofA. craccivora transmitted both green andchlorotic rosette, whereas races from Ugandaand Kenya, which transmitted chlorotic rosette,failed to transmit green rosette. There has beenno report of comparative virus-vector relation-ships of the symptomatically different types ofrosette viruses occurring in Nigeria.

Present studies at the Institute for AgriculturalResearch, Samaru, Nigeria have indicated thatthey are both transmitted by A. craccivora. Anattempt is being made to find out if they aredifferent strains of the same virus and what isthe epidemiological significance.

CICADELLID LEAFHOPPERS. These insects arefound throughout the cropping season. Theirfeeding damage can be quite serious and workis in progress to evaluate the losses caused bythem.

GROUNDNUTLEAF BEETLES. The adults chew orpuncture the leaves but do not cause as muchdamage as the cicadellid leafhoppers.

BLISTER BEETLES. They are known to cause

heavy damage to groundnut flowers; thespecies involved are Coryna hermanniea F.;Mylabris trifasciata Thunbs; Decaptoma affinis Oliv. and Epicauta spp (Misari and Raheja 1976;Raheja and Misari, in press).

Postharvest and storage pests

The decline in groundnut production in Nigeriais greatly amplified by losses incurred at andafter harvest, especially in storage. Severalinsect species are responsible for heavy lossesof postharvest groundnuts due mainly to theinadequate storage facilities of farmers and tothe ignorance of the government agenciesabout the need for entomologically sound stor-age depots. Over 40 storage insect pests havebeen reported as infesting groundnuts in store(Comes 1964).

The major storage pests are the groundnutseed beetle (Caryedon serratus F.); flat grainbeetle (Cryptolestes ferrugineus Steph.);khapra beetle, (Trogoderma granarium Ev.);merchant grain beetle (Oryzaephilus mercator Faur.); red rust flour beetle {Tribolium cas-taneum Herbst); confused flour beetle(Tribolium confusum); tropical warehousemoth (Ephestia cautella Wlk.); rice moth (Cor-cyra cephalonica Staint.); Aphanus sordidus F.;and Indian meal moth (Plodia interpunctella Hub.).

All told, a groundnut producer experiences5-35% damage to his crop annually frominsect pest attacks in Nigeria. At present, it iseconomically unrealistic to recommend theroutine use of pesticides.

Weeds

They constitute one of the greatest bottlenecksto production (Musa and Kaul 1978). Generallythere is about 18-70% (average 50%) lossfrom weeds recorded in Nigeria.

The parasitic species Alectra vogelii Benth. ofthe family Scrophulariaceae is a major threat togroundnut producers. This parasitic floweringplant causes yellowing of the foliage and poorpod set and seed development. It attacks thegroundnut root system and taps the host'snutrient energy source through a conspicuousknot which is formed at its point of attachmentwith the host.

The pest appears to be widespread th rough-

270

out the producing areas where its deleteriouseffect is becoming increasingly recognized. Theassessment of yield loss due to this parasite andits control remain to be determined.

D iseases

Severe damage was done to 0.7 million ha byrosette virus in 1975. South of 11!/2° northlatitude, leaf spots cause pod losses of20-50% everywhere each year. In 1976 peanutrust appeared.

Seedling wilts are serious locally but wilts ofolder plants have not been so. Pod rots havebeen significant in some fields at Samaru insome years. No work has yet been done withresistant varieties.

No progress has been made on resistance toaflatoxin. The need is greaterthan before, with a planned expansion of crop in the northernGuinea Savanna. The only large commercialcrop bought was in 1972 (half a million m.tons), and this had acceptably low aflatoxinlevels. It was a favorable season however, withgood drying weather after harvest for mostgrowers.

Rust

The disease is now endemic in the country andhas become more damaging each year since itappeared in 1976. So far no significant attackhas been recorded north of 11 Y2°N latitude, butsouth of it there is now widespread and seriousdamage.

Rust was severe at many sites in 1980 es-pecially in the southern and western areas. It hasbeen observed many times that rust is lesssevere in late planted crops.

Leaf Spots

Control of the Mycosphaerella early and lateleaf spots remains a major objective. For mostfarmers, medium volume spraying is not practi-cal and VLV and ULV techniques are in-sufficiently researched. Spraying would be re-quired to control rust as well as leaf spots.

The following species have shown resistancein the field: Arachis chacoense against Cercos-pora arachidicola (early); and A. cardenasii against Cercosporidium personatum (late). Anun-named species HIK 4.10 (Hammons,

Langford and Krapovickas collection), andUSDA introduction number PI 338280 haveshown some resistance to both leaf spots.

No effective field resistance to leaf spots hasbeen established from crosses made to date. A variety needs resistance to both leaf spots to besatisfactory. Usually both are present at highlevels but with great variation in proportion toeach other, from spot to spot within the field,between fields, sites and seasons.

It is possible that races of the leaf spots maybe present. The leaf spots cause by far thegreatest losses of yield which groundnut grow-ers suffer.

Rosette

The groundnut rosette virus disease is by farthe most damaging virus disease of the crop inNigeria. The form of the disease is "NigerianGreen Rosette". "Chlorotic Rosette" also oc-curs at a low incidence level.

Rosette disease in the past has caused moredamage south of latitude 11°N than in the mainproducing areas which lie north of it.

Losses due to rosette are estimated to be3% per year from all groundnuts grown in theSudan and northern Guinea Savanna Zones.

Early planting and close spacing aresafeguards against rosette, ft is not alwayspossible to achieve and it is not effective againstepidemics like the 1975 outbreak. Rosette resis-tant varieties are needed to keep the disease incheck and insure growers against one of thehazards of the crop.

Effective resistance has long been recognizedin collections from Upper Volta, Cote d'lvoires,Cameroun and other places. It has not beenfound in Nigeria. The CNRA Bambey, Senegallines have proved to be highly resistant to theNigerian Green Rosette and recent screeninghas shown that lines resistant to green rosetteare also resistant to Nigerian chlorotic rosetteand vice-versa.

It is not difficult to incorporate rosette resis-tance into acceptable varieties with a range ofseason lengths. Recent introductions from theUpper Volta Program (RMP 12, RMP 91) haveproved highly resistant and very productiveover many sites in the northern and southernGuinea Savannas. No satisfactory rosette resis-tant lines are at present available in Nigeria and

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work continues to improve the Upper Volta lineKH 14-9A. Rosette resistant, drought material isneeded forthe northern areas where the uplandcrop is at risk from aphids associated withirrigation projects.

Pod Set Failure

The problem of blind or unfilled pods (Yayock1979) is extensive. In 1978 there were wide-spread crop failures where vegetative growthwas good, but hardly any pods developed.

The causal factor(s) for blind or unfilled podsis not known. Items which have been investi-gated are insect infestations, disease, late plant-ing and weather. Rainfall, moisture stress,temperature levels and diurnal differencescould be involved and linked with nutrientuptake and transport.

ReferencesABALU, G. 0. I. 1978. An economic analysis of

groundnut production In the northern Nigeria.Pages 83-90 in Proceedings of the National Seminaron Groundnut Production, Kano, Nigeria, Feb 1978.

A'BROOK, J. 1964. The effect of planting date and spac-ing on the incidence of rosette disease and of thevector. Aphis cracclvora Koch, at Mokwa, NorthernNigeria. Annals of Applied Biology 54: 199-208.

A'BROOK, J. 1968. The effect of plant spacing onnumber of aphids trapped over groundnut crop.Annals of Applied Biology 61: 289-294.

AGBOOLA, S. A. 1979. An agricultural atlas of Nigeria.Oxford University Press. 248 pp.

AKINFEWA, S. 1977. Report on aphid and groundnutrosette project. Groundnut conference, Kano, 1977.

AKINFEWA, S. 1978. Aphis cracclvora Koch and rosettevirus disease of groundnuts in Nigeria. NigerianGroundnut Board. 1978.

B ENOIT, P. 1977. The advance of rainy season in north-ern Nigeria. Samaru Agricultural Newsletter19: 61-66.

BOOKER, R. H. 1963. The effect of sowing date andspacing on rosette disease of groundnuts in north-em Nigeria, with observations on the vector, Aphis cracclvora. Annals of Applied Biology 52: 125-131.

Bos, W. S. 1977. Aphelanchoides arachidis n. sp(Nematode: Aphelenchoidea), an endoparasite ofthe testa of groundnuts in Nigeria. Journal of PlantDiseases and Protection 84: 95-99.

CORNES, M. A. 1964. A revised list of the insectsassociated with stored products in Nigeria. Pages31-34in Nigerian Stored Products Institute, AnnualReport 1964, Technical Paper No. 4.

FEAKIN, S. (ed.) 1967. Pest control in groundnuts.PANS Manual No. 2; 1st Edition. 192 pp.

FETUGA, B. L, and OGUNFOWORA, 0.1976. The supplyand utilization of some major oilseeds and oilseedcakes in Nigeria. Nigerian Journal of Animal Produc-tion. 3: 43-52.

HARKNESS, C. 1977. The breeding and selection ofgroundnut varieties for rosette disease in Nigeria.Text submitted as an entry for the AfricanGroundnut Council Prize for 1977,45 pp.

HARKNESS, C, KRIESEL, H. C, and DAGG, M. 1971.National Agricultural Development Committee. 2.Report of the study group on groundnuts. Nigeria,Federal Department of Agriculture, Lagos.

HULL, R., and ADAMS, A. M. 1968. Groundnut rosettevirus and its assistor virus. Annals of Applied Biol-ogy 62: 139-145.

JOHNSON, R. A. 1978. Soil pests of groundnuts inNigeria. Proceedings of the National Seminar onGroundnuts Production, Kano, Feb 13-14, 1978, 7 pp.

JOHNSON, R. A., AKINFEWA, S., and RAHEJA, A. K. 1978.Pre- and post-harvest crop protection pests ofgroundnuts in northern Nigeria. Paper prepared forthe Third General Conference of Association for theAdvancement of Agricultural Sciences in Africa,Ibadan, Nigeria, April 9-15,1978. 15 pp.

MISARI, S. M. 1974. Report on Groundnut Entomologyfor the 1974 season to the Board of Governors of theInstitute's Work 1974-1975. Groundnuts andOilseeds Improvement Programme; I.A.R./ABUSamaru, Zaria, Nigeria.

MISARI, S. M. 1975. Insects and other arthropod pestsof groundnuts in Northern Nigeria. AgriculturalNewsletter 17(1): 4-9.

MISARI, S. M. and RAHEJA, A. K. 1976. Notes on fieldpests of groundnuts In northern Nigeria. Inter-national Symposium of Field Pests of Groundnutsand Millet, Kaolack, Senegal, 21-23 April, 1976.66-79 pp.

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MUSA, H. L, and KAUL, R. N. 1978. Weed controlstudies on groundnuts with reference to selectedequipment and systems. Pages 59-64 in Proceed-ings of the National Seminar on Groundnut Produc-tion, Kano, Feb 13-14,1978.

OKUSANYA, B. A. M. 1965. Page 129 in RothamsteadExperiment Station Report 1964.

OKUSANYA, B. A. M., and WATSON, M. 1966. Host rangeand some properties of groundnut rosette virus.Annals of Applied Biology 58: 377-387.

OLAYIDE, S. O., et. al. 1972. A quantitative analysis offood requirements, supplies and demands inNigeria, 1968-1985. Federal Department of Agri-culture, Lagos.

OYENUGA, V. A. 1968. Nigerian feed and feeding stuffs.Their chemistry and nutritive value. Ibadan Univer-sity Press. 99 pp.

PERRY, D. A. 1967. Premature death of groundnutplants in northern Nigeria. Experimental Agriculture31: 211-214.

R AHEJA, A. K. 1975. Millipedes on groundnuts,4racri/shypogaea L. Nigerian Journal of Plant Protection1(1): 91-92.

RAHEJA, A. K., and MISARI, S. M. (Submitted to Press).Pests of Groundnuts. A chapter in Pests of Crops inAfrica, H. F. Van Emden, S. R. Singh and T. A. Taylor(eds.), John Wiley and Sons.

ROSSEL, R. W. 1977. Some observations and experi-

ments on groundnut rosette virus and its control inNigeria. Samaru Conference paper 9.

SANDS, W. A. 1962a. Technical Report of the RegionalResearch Station, Ministry of Agriculture, NorthRegion, Nigeria. 26.

SANOS, W. A. 1962b. The evaluation of insecticides assoil and mound poisons against termites in agri-culture and forestry in West Africa. Bulletin ofEntomological Research 53: 179-192.

STOREY, H. H., and BOTTOMLEY, A. M. 1925. Transmis-

sion of rosette disease of the groundnut. Nature,London 116: 97-98.

WOOD, T. G., JOHNSON, R. A., and OHIAGU, C. E. 1977.

Populations of termites (Isoptera) in natural andagricultural ecosystems in Southern GuineaSavanna, near Mokwa, Nigeria. Geo-Eco.-Trop.1: 139-148.

YAYOCK, J. Y., ROSSEL, H. W.,and HARKNESS. C. 1976. A

review of the 1975 groundnut rosette epidemic inNigeria. Pages 129-137 in the African GroundnutSymposium on Pests of Groundnuts and Millet inthe Field; Kaolack, Senegal, 21-23 April, 1976.

YAYOCK, J. Y., HARKNESS, C, and JOHNSON, R. A. 1978.

Groundnuts: What went wrong in 19787 FDAGroundnut Rehabilitation Committee, March 1979.Institute of Agricultural Research, Samaru, Nigeria.Reports to Board of Governors.

ZIMMERMAN, A. 1907. A disease of peanuts, Arachis hypogaea L. Pflanzer, 3: 129-133.

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Groundnut Product ion and Research in Senegal

J. Gautreau and 0. De Pins*

Product ion

Groundnuts constitute the main cash crop ofSenegalese agriculture, with most of the pro-duction being turned into peanut oil. They playan important role in the economy of the coun-try, even though during the last few yearsemphasis has been placed on the developmentof food crops. They represent between one-third and one-half of the total exports fromSenegal.

The groundnut basin covers an area of ap-proximately 3 million hectares of which, on theaverage, 1.1 million ha are sown withgroundnuts every year. During the last twodecades the area planted has remained fairlystable, whereas the yields have fluctuated de-pending on theincidenceof droughtperiods. Asa result, crop production has varied greatly(Table 1). The record production in 1975 ex-ceeded 1.4 million metric tons. The 1980 cropseason is being compromised by the sig-nificantly late arrival of the rains.

The priority aim of the Senegalese Govern-ment is to stabilize groundnut production at a maximum limit of 1.2 million metric tons ofunshelled groundnuts. This regulation wouldminimize the fluctuation in metric tons ex-ported, and consequently stabilize the annualincome of the producers.

Organizations and Assistanceto FarmersThe farmers are grouped into cooperativeswhich supply them with production inputs andgather products such as groundnuts at the locallevel.

Several organizations cooperate for aid anddevelopment in the rural sector (Sene 1980).Briefly they are:

* Institut Senegalais de Recherches Agricoles (ISRA),National Agronomic Research Center (CNRA), BP51, Bambey, Senegal.

1. SONAR, a new national organizationwhich supplies the farmers and managesthe seed capital.

2. SODEVA, a regional society for rural de-velopment, which operates within thegroundnut basin. It is in charge of allproduction activities and provides techni-cal and cooperative assistance for thegrowers.

3. The CERP centers (multi-purpose centerfor rural expansion) have an important aidrole at the rural community level, in strictcooperation with the regional society fordevelopment. They provide the localpeople with technical services.

4. The National Seed Service created in 1972produces, controls and looks after the seedcapital. Its role is particularly important forgroundnuts especially because the annualrequirement of recommended seeds is ofthe order of 100-130 000 t (Lam andDelbosc 1977).

Climate and Soi l Condi t ions

Senegal at the western tip of Africa, is under theinfluence of the Sahelo-Sudanian climatecharacterized by a single rainy season, usuallyshort, and interrupted by frequent periods ofdrought. Lack of water has been the mainfactor limiting production in a large part of thegrowing zone for 10-12 years.

The north-south rainfall gradient is very sig-nificant: 1000 mm in 5 months in the Casa-mance and 300 mm in 2.5 months in the north(Mauboussin 1973). Due to the recent years ofdrought, there has been a disturbing slippageof isohyets towards the south and a shorteningof the period of useful rains. The consequencesare serious in the northern half of the country, a zone where groundnuts are suffering more andmore, often from lack of water.

The groundnut growing soils have a sandy

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Table 1. Peanut oil production in Senegal, 1960-1977.

Area Production YieldCrop season (000 ha) (00 tons of unshelled peanuts) (kg/ha)

1960-61 975 890 9151961-62 1025 995 9701962-63 1015 915 9001963-64 1085 950 8801964-65 1055 1020 965

1965-66 1115 1120 10051966-67 1115 855 7701967-68 1165 1005 8651968-69 1190 830 6951969-70 955 790 830

1970-71 1050 585 5551971-72 1060 990 9301972-73 1070 570 5301973-74 1025 675 6601974-75 1050 980 930

1975-76 1205 1410 11751976-77 1345 1210 8951977-78 1115 520 465

Average 1190 905 830

Standard 93 227 184deviation

CV<%) 7.8 25.1 22.2

Source: Annual DGPA reports quoted by BCEAO informative notes, No. 277, November 1979.

texture (Charreau 1961) with low clay content(4% for the soil called "dior") and a low mois-ture holding capacity (6-10% on a weightbasis) and also a low mineral content.

A g r o n o m y

The 2-year rotation of groundnuts and milletis currently being practiced by most producers.The population growth has brought about a progressive decrease in fallow land in thegroundnut basin where the relative role ofgroundnuts in agriculture has decreased to thebenefit of food crops.

The main cultivation operations (planting,hoeing, digging) are performed with small im-plements drawn by horse or donkey. The use ofoxen for traction is expanding, but is still prac-ticed by a minority of growers.

Chemical fertilization is common, but its lowaverage level of application does not properly

compensate for the mineral uptake by the crop.The amount of complex NPKS fertilizers usedannually varied from 20 000 to 40 000 tonnes,wi th a maximum dose of 40 kg/ha. Onlyspecially assisted edible peanuts (30 000 t in1976) are fertilized according to the researchrecommendation of 150 kg/ha of 8-18-27.

Planting takes place in June or July and theharvest is in October or November, dependingon the region. Hand threshing is done on thespot after curing in November or December.After cleaning, the groundnuts are delivered intheir pods to the cooperative.

C r o p P r o t e c t i o n

A combined fungicide-insecticide is generallyused on the seeds to protect them from damp-ing off and from predators. Invasions by insectsand myriapods during the growing season aretransitory and relatively slight, although during

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the last few years significant millipede damagehas been observed at emergence time andduring the pod formation.

Various groundnut leaf diseases exist. Cer-cospora leaf spot can have a serious impact inthe southern part of the country. Groundnutrust appeared in 1978-1979 but with noeconomic consequences up until now.

The problem of seed contamination by As-pergillus flavus has existed for several years.The formation of mycotoxin is encouraged bythe more and more frequent periods of droughtoccurring during the maturing stage. Until re-sistant varieties become available, Senegal hasstarted a pilot industrial unit for the chemicaldetoxification of peanut meal, and is experi-menting with various electronic screening pro-cedures for seeds.

Variet ies

The climatic conditions prevalent in Senegalnecessitate the use of varieties adapted to therainfall constraints. The maturity cycles rangefrom 120 to 130 days in the south, to 90 days atthe northern limit of the cultivation zone. Con-tinuous breeding research has enabled thecreation of several varieties which are betteradapted to the various ecologies (Gautreau1980). Most of the groundnut varieties croppedin Senegal were recommended by research.

In the south, 69-101 is a Virginia varietyresistant to rosette and derived from the28-106 variety for which the cultivation zone isfurther north (Fig. 2). In the center, and north-central regions, 73-33 is a new drought resistantvariety with a 105-day maturity cycle. It hasbeen released recently (until resistant varietiesbecome available), and will be cultivated onapproximately 260 000 ha. The 55-437 variety isa 90-day Spanish commonly grown in thenorthern part of the basin. Its nondormancylimits its expansion to the south where a newvariety with the same cycle, but dormant, iscultivated. The 57-422 variety is a Virginia typewith large seeds and a 105-day maturity cycle.Lastly, GH 119-20 of American origin is culti-vated for edible peanuts in the Sine-Saloumregion.

Groundnut Researchand Objectives

The first research in Senegal was conducted inFigure 2. Migration of the isohyets in Senegal

from 1931-1977.

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the twenties. In 1975, the various organizationswhich were involved in agricultural researchtransferred to a national organization — theSenegalese Institute for Agricultural Research(ISRA) under the guidance of the Ministry ofScientific and Technical Research (SERST). Re-search is carried out in stations all around thecountry and in the multilocation experimentalfields in the farmers' environments.

G r o u n d n u t B r e a d i n g

The breeding objectives of the SenegaleseInstitute for Agricultural Research (ISRA) areimprovement to drought; resistance to rust,leaf spot, and Aspergillus flavus; and the crea-tion of edible peanut varieties and peanuts forconfectionery use.

Improvement of GroundnutResistance to Drought

The decrease of rains in the Sahel has causedbreeders to create varieties better adapted todrought (47-16, 50-127, 73-33, 55-437) whichhave shown good performances in dry con-

ditions (Bockelee-Morvan at al. 1974). To do this,the two breeding and physiology divisions ofthe National Agronomic Research Center(CNRA), in Bambey, collaborate very closely.The two methods being used are shortening ofthe growing cycles (using the parent "Chico"),and screening lines or varieties with a goodtolerance to drought.

In addition to research on better adaptation todrought, different types of improved yieldmaterial are being screened (Tables 2,3,4, 5).

Breeding for Resistance to Rust(Puccinia arachidis Speg.)

This new program has been designed tocounter the threat resulting from the recentappearance of groundnut rust in West Africa.The incidence of this disease in crops varies; itdepends on how early the invasion com-mences.

It has been possible (1) to obtain the mainsources of resistance, DHT 200, Tarapoto,Israel line 136, and FESR lines 1-14 promotedby the USDA; (2) to verify in Upper Volta theirresistance to the type of rust common in West

Table 2. Var iety t r ia l resul ts, Bambey (average yields of poda In k g / h a ) .

Note: The V 755 variety called 79-2 is likely to replace 57-422 (superior yield of 5% In station experiment*; shelling rate • good seed rate = 5.5%, 100-karnel weight - 60-65g.)

1.7%;

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MaturityVarieties (days) 1975 1976 1977 1978 1979 Average

55-43773-30

3125 253090 2745

2125 2250 2200 244555-43773-30

3125 253090 2745 2390 2160 1770 2265

73-3357-422

3965 2600105 3245 2960

2040 2120 2115 257073-3357-422

3965 2600105 3245 2960 2120 2330 2210 2575

Table 3. Variety t r ia l w i t h yields expressed as a percentage of the best cont ro l lines (10repl icat ions/var ie ty = 105 mVvar le ty ) .

Lines Origin 1977 1978 1979

V37 (28-206 x 48-115) 57-4222 112 109 118V 41 " 118 102 103V 55 " 115 116 147V 58 " 114 107 108V 59 " 108 110 103V 79 55-437 (48-115 x 28-206) 114 107 100V 755 55-437 x 57-313 107 100 108

Africa; and (3) start a complete breeding pro-gram to transfer these resistant genes to thereleased varieties.

Recently, a fruitful exchange of plant materialwith ICRISAT permitted the use of two newparents NC-Acc 17090 and EC 76446 (292) for

cross-breeding. It also provided the first segre-gating generations of 45 families of crossbredvarieties for resistance to rust. The screening ofthese different progenies should start with the1981 crop season. However, since the disease isstill not very prevalent in the country, one

Table 4. Average yield (pods kg/ha) in Bambey of some recent in t roduct ions; varietalexperiments — 10 repl icat ions; 147 m2 variety.

Introductions 1976 1977 1978 1979 Average

TG 7 (India) 2640 2050 2345TG8 " 2425 2575 1670 2225TG 9 " 2425 2615 1585 2210TG 14 " 2225 1980 2100Faizpur (India) 2810" 2015 1930 2050 2200

UF 72-101 (USA) 2650* 1880* 2210 1985 2180UF 73-217 " 1990 2505 2275 2255Early runner 2215 2175 2195Comet 1815' 2005a 2205 2250 2320Spanhoma 3010a 2490 2115 2110 2430

Spancross 2205a 2215 2145 2190Florunner 2725 1710* 2315 2270 2255Starr 2890a 2400* 1870 2385Egret 1900 1350 162555-437 2665b 2125 b 2105b 2130 2255

57-422 2850b 2235d 2465c 2110b 241573-33 1940b 2060d 2095c 2025* 2280

a. Varietal trial with 4 replications.b. Average of 2 varietal trials.c " 3 "d. " 5 " "

Table B. Average yie ld (pods kg /ha) of some int roduct ions tested near Louga. Uol tyet = 300 m m ;experiments w i t h 7 repl icat ions-84 mVvar ie ty .

Varieties 1975 1976 1977 1978 1979 Average

Argentine 560 900 105 920 155 530

Starr 305 885 90 1060 195 510Spanhoma 525 765 55 900 560Tifspan 510 885 70 860 580Spancross 245 940 110 1380 110 560Comet 350 880 80 1185 105 540

Florispan 385 720 70 1230 130 510

Faizpur 80 945 135 385Chico 355 35 425 75 22073-30 340 730 90 1070 150 47555-437 385 815 95 1180 180 530

Rainfall (mm) 317 289 169 326 223

279

foresees that, for the time being, the breedingmethods will be limited to laboratory tests in a closed area, such as with the test of inoculationof leaves maintained on Hoagland mediums(Subrahmanyam et al. 1980). For securityreasons, it is intended to avoid the use ofbreeding methods involving artificial contami-nation in open fields.

Breeding for Varietal Resistanceto Leaf Spot (Cercospora personata)

Results of experiments carried out in southernSenegal (Casamance) show that this diseasecan bring about a loss of 30-40% in yield. As oftoday, there is no effective solution to thisdisease. The main problem is the lack of geneticvariability with regard to this characteristic inthe Bambey collection. A search for possiblesources of resistance is under way at the pre-sent time.

Varietal Resistanceto Aspergillus flavus Link

Research in this field is extremely importantbecause of the serious consequences for thehealth of people and animals due to the pres-ence of aflatoxin in the seeds and peanut meal.The economic importance is easily understoodsince 300 000 tons of peanut meal are exportedfrom Senegal every year which must satisfy therecent norms of the importing countries — lessthan 50 parts per billion.

The breeding program in Bambey against A.flavus is at the F5 stage. The parents used arethose received from the USDA and identifiedby Mixon and Rogers —PI 337 409 and PI337 394.

The two selection tests used are (1) inocu-lation in Petri dishes (Zambettakis et al. 1977)and (2) measuring the aflatoxin content by theVelasco method. A third test based on themeasurement of the seed coat permeability toions has been evaluated for its reliability (Cam-era 1977). Its first results seem to correlate withthose of the artificial inoculation test which ismore involved.

The early variety 55-437, cultivated through-out the northern part of the groundnut basin,shows as equally good resistance to A. flavus asthe two USDA parents used.

The thickness and hardness of the shell as

well as an appreciation of the texture of theseed coat are also used (Zambettakis andBockelee-Morvan 1976; Waliya and Abadie1978) as criterion of resistance. This research iscarried out in collaboration with the Museum ofNatural History in Paris.

Creation of Edible Confectionery Varieties

Senegal hopes to achieve more valuablegroundnut production by increasing the cultiva-tion of edible and confectionery peanuts forexportation through a favorable and expandingmarket.

Such varieties must fit the technologicalnorms specified at the level of various channels.Generally one tends to get a well-formed, con-stricted pod with large and round seeds. A goodrepresentative type is GM 119-20 coming fromthe United States. Variety 756 A is also grown inSenegal. It will soon be replaced by the new73-27 (GH 119-20 x 756 A) which scores betterin grade and productivity.

Certain Spanish varieties such as 55-437,75-33, and 75-50 (Faizpur) correspond well withthe Hand Picked Standard (HPS) norms for theconfectionery peanut market.

A g r o n o m y

Long-term studies have been carried out in theCNRA by multi-disciplinary teams in farmingtechniques, soil management and root-growthsystems; crop rotations and farming systems;fertilization and rhizobiology; and agro-climatology.

Bioclimatology studies are particularlyneeded to evaluate the water requirements ofgroundnuts (Dancette and Hall 1979).

C r o p P r o t e c t i o n

Work is being conducted on the screening of thebest efficient insecticides to control the maingroundnut pests: millipedes (Odontopygidae), termites (Eutermes parvulus), larvae (Amsacta moloneyi and Spodoptera littoralis), bugs(Aphanus sordidus), and bruchids (Caryedon fuscus); selection of active nematocides; screen-ing of active leaf fungicides mainly againstrust and Cercospora leaf spot; testing of variousherbicides; studies on stock protection; andpesticide residue studies.

280

P o s t h a r v e s t T e c h n o l o g y

The main subjects being studied in col labo-ration wi th industry and various organizationsare: grading of edible and confectionery peanuts;electronic screening of seeds contaminatedwi th A. flavus; detoxif icat ion of peanut mealwi th gaseous ammonia ; and studies on storagemethods, both cold storage or vacuum packs.

Conclusion

Groundnuts have consti tuted an essential re-source of the Senegalese economy for a longt ime, but the average product ion for the last 20years stil l fal ls very short of the 1.2 mi l l iontonnes op t imum levels set by the authorit ies.This si tuat ion is mainly due to more and morefrequent years of a signif icant lack of rainfalland an apprec iab le delay between the es-tab l ished cul tura l techn iques suggested byresearch and the more or less improved tra-dit ional practices of most of the producers.

Tangible results were obtained due to theactivities contr ibuted by the agricultural aidorganizations. However, a great deal of work isstill necessary. The recent administrat ive re-fo rm should make it easier. On the other hand, itis up to research to prove a renewed dynamismto face new calamit ies wh ich threaten the in-come of g roundnut producers (drought, rust,Cercospora leaf spot, aflatoxin) and to cooper-ate even more closely w i th the agricultural aidservices.

References

BOCKELEE-M ORVAN, A., GAUTREAU, J., MORTREUIL, J. C,

AND ROUSSEL, O. 1974. Results obtained withdrought-resistant groundnut varieties in WestAfrica. Oleagineux 29(6): 309-314.

CAMARA, P. A. 1977. Permeability testing of the thinskin of groundnut seeds. Oleagineux 32(6): 273-276.

CHARREAU, C. 1961. The dynamics of water in two

types of soil in Senegal. Agronomie Tropicale16(5): 504-562.

DANCETTE, C, and HALL, A. E. 1979. Agroclimatology

applied to water management in the Sudanian andSahelian zones of Africa. In Agriculture in semi-aridenvironments. Ecological studies Vol. 34.

GAUTREAU, J., 1977. Levels of intervarietal leaf poten-tial and adaptation of groundnuts to drought.Oleagineux 32(7): 323-331.

GAUTREAU, J., GARET, B., and MAUBOUSSIN, J. C. 1980.

A newvariety of Senegalesegroundnuts, adapted toperiods of drought: variety number 73-33.Oleagineux 35(3): 149-154.

LAM, M., and DELBOSC.G. 1977. A tool for developmentcreated in Senegal: the seed service. Oleagineux32(1): 15-19.

MAUBOUSSIN, J. C. 1973. The objectives of varietalimprovement in the face of environmental con-straints. Colloque de Rufisque, Janvier 1973.

MIXON, A. C, and ROGERS, K. M. 1973. Peanut resistant

to seed invasion by A. flavus. Oleagineux28(2): 85-86.

SENE, D. 1980. On reform and redynamization of aidstructures in the rural sector. Ministers du develop-pement rural du Senegal, April 1980.

SUBRAHMANYAM, P., GIBBONS, R. W., NlGAM, S. N.,

and RAO, V. R. 1980. Screening methods and furthersources of resistance to peanut rust. Peanut Science7: 10-12.

WALIYAR, F., and ABADIE, M. 1978. The penetra-

tion of mycelium of Aspergillus flavus Linkinto the groundnut seed coat after arti-ficial contamination — ultrastructural analysis.Oleagineux 33(8): 447-453.

ZAMBETTAKIS, C, and BOCKELEE-MORVAN, A. 1976. Re-

search on the seed covering of groundnut seeds andits influence on penetration by A flavus. Oleagineux32(5): 219-228.

ZAMBETTAKIS, C, BOCKELEE-MORVAN, A., WALIYAR, F.,

and ROSSION, J. 1977. Varietal differences ingroundnut sensitivity to contamination by A flavus. Oleagineux 32(8): 377-385.

281

Groundnut Product ionand Research Problems in the Sudan

H. M. Ishag, M. A. A l i and A. B. Ahmad i *

Product ion

Groundnut is an important cash crop in theSudan, the largest country in Africa. It provides7% of the GNP and employs 12% of the popu-lation. Sudan is the fourth leading country ingroundnut production after India, China, andthe United States. Production has increased bya bout 320% since 1965. The three major regionsof groundnut production are Gezira and Man-agil (42%), North Kordofan (17%) and SouthDarfur (14%). The average pod yield is low,being 600 kg/ha in rainfed areas and 1440 kg/hain irrigated areas.

There are several distinctive climatic regions.In the north, temperatures are high and rainfallis scanty and irregular, while in the southrainfall is heavy — up to 1400 mm. Soils areclassified into four groups (Said and Mustafa1978) — (a) soils of the central clayplain, (b)sandy soils of western and northern Sudan, (c)desert soils and sands of the northern half of theSudan, and (d) alluvial and riverine soils alongthe Nile and its tributaries. The total area suit-able for cultivation is about 200 million feddans.There are 16 million feddans under cultivationof which only 4 million are irrigated. (Onefeddan =1.04 acres = 0.42 ha.)

Crop Management

Rainfed AreasIn sands of the western region of Sudan, theearly maturing variety Barberton is sown byhand when the rains start This variety maturesin about 100 days. Seed dressing with Aldrex T is practised by most of the farmers. Plantpopulation is low. No fertilizers are used and

* Agricultural Research Corporation, Wad Medani,Sudan.

weeds are controlled by hand. Proper rotationsare not followed and shifting cultivation is thenormal practice. Crops grown with groundnutsare sesame, roselle [Hibiscus sabdariffa L.) andmillet.

Irrigated Areas

Groundnut in irrigated areas is normallyplanted in June in a row spacing of 80 cm withabout 30 cm between plant holes and with 1-2seeds per hole. Different rotations are adopted;in Gezira, a four course rotation (cotton-wheat-groundnuts/sorghum or rice-fallow); inManagil, a three-course (cotton-wheat-groundnuts/sorghum); and in Suki and Rahad, a two-course (cotton-groundnuts). Watering isevery 2 weeks, and a light watering is given7 days before harvest to facilitate pulling ofgroundnuts as the soils are heavy clay. Tenantsnormally delay harvest and this causes losses ofpods in the soil. In most areas, weeding iscarried out by hand, while some governmentschemes use herbicides.

Past Research Achievements

A g r o n o m y

Disc plowing six inches deep, two passes ofdisc harrow, or rotovation, followed by levellingand ridging has increased pod yield substan-tially (Ishag et al. 1980). A single plant at 7.5 cmspacing between plants has resulted in higheryields (Tahir and Misovic 1967). Ishag (1970)found that 15 cm between plants and two seedsper hole significantly outyielded 30 cm spacing.Planting unshelled pods usually results in lowyields mainly because of a sparse plant popula-tion stand. High pod yield is achieved from earlyJune planting (Ishag 1965). The average seed-ing rate in irrigated areas is about 30 kg (shelled

282

basis). Recent work (Ishag et al. 1980) showed a marked responseto phosphorus when suppliedwith the seeds.

G r o u n d n u t B r e a d i n g

Groundnut improvement by selection in Sudanstarted with the screening of the Tozi collectionassembled by A. H. Bunting (1954-55). Tahir(1965) made a few crosses in 1949. The line MH383, introduced from Nigeria but originallydeveloped in India, was selected for productionin the irrigated Vertisols of central Sudan (ElAhmadi 1965-66, 1969-70 and Nur 1976).

Recently, breeding has received more atten-tion and a full time breeder is now in charge of a program aimed at the development of highyielding, early maturing, spreading bunch typesadapted to the irrigated Vertisols; selection ofearly maturing, drought tolerant cultivars forthe rainfed sandy soils of western Sudan; selec-tion of large seeded Virginia types for produc-tion in northern Sudan; development ofgenotypes with increased resistance to infec-tion by Aspergillus flavus and aflatoxin produc-tion; and development of genotypes with highoil content and high kernel yield.

Hybridization work started in 1978. Breedingmaterial is being assembled from the UnitedStates and ICRISAT, and close contact with theICRISAT program will be maintained.

Pes ts a n d D iseases

Interest in pests and diseases of groundnuts inthe Sudan started in the late sixties when thecrop was introduced into the rotation of theGezira agricultural scheme. The following in-formation has been obtained from old recordsand recent surveys and research:

Bird, Insect and Rat Pests

According to Ahmed and El Amin (1976), crowsCorvus a/bus (Mull.) and doves (Streptopelia decipiens) may inflict some damage duringJune and July by picking up unburied or badlyburied seeds. This loss usually ends by the firstirrigation or rain.

Millipedes (Julidae) appear in great numbersat the beginning of rains and they chop thetender parts of the crop at night. During the day,millipedes hide under the shade of trees, loose

barks, and in soil cracks and depressions.Termites (Microtermes thoracalis) (S. jost),

Macrotermes bellicosus (Smeath) and M.natulenses (Hak.) cause sporadic damage.

The chaffer grub (Schizomycha cibrat) feedson the subterranean parts of the plant. Some-times the embedded larvae of an unidentifiedyellow grub may feed on the inside tissue of thestem and cause wilt.

Thrips, Caliothrips impurus (Pr.) and Calio-thrips sudanensis (Bagn and Cam), usually ap-pear in large numbers in mid August but rarelyget serious. Aphids {Aphis craccivora) usuallyattack late sown groundnuts in irrigated areas.

The following minor pests many of whichwere noted by Clinton (1960) and Ali et al. (1970)in rainfed areas, have been found ongroundnuts:

Egyptian leaf worm (Spodoptera littoralis) (Boist); leaf roller, Cosmophila flava (F);whitefly (Bemesia tabaci) (Genn); green bug(Nezara viridula (L); stainer bug (Dysdercusspp); American bollworm, Heliothis armigera (Hb); and grasshoppers (Ailopus spp andCatantops spp.).

Field rats (Mastomys natolensis macrelepsis (Sund)) occasionally attack seeds before ger-mination.

Diseases

At present there are no serious diseases ingroundnuts, yet the following diseases wererecorded in different parts of the Sudan by Tar(1955), Ali et. al (1970), El Nur and Ibrahim(1970) and Khalifa (1973):

Cercospora arachidicola (Hori) (early leafspot) and Cercosporidium personatum (Berkand Curt) (late leaf spot) occur late in the seasonand according to Khalifa (1973) they do notreduce yield significantly.

Rust, Puccinia arachidis (Speg), was first re-corded by Ali (1978) in both rainfed and irri-gated crops in the Sudan. It occurs very late inthe season and its effect on yield is not yetassessed.

Crown rot caused by Aspergillus niger (VanTieghem), Phyllosticta sp causing leaf spots,and the rosette disease were recorded by Tar(1955) in the early fifties.

A leafmottle caused by a virus disease hasbeen recorded in some parts of the country byHashim (1975).

283

Very sporadic wi l ts have been noted in somefields and the fo l l ow ing pathogens were iso-la ted (A l i 1980) f r o m w i l t i n g p l a n t s : Ma-crophomina sp ; Fusarium s p p ; Rhizoctonia solani (Kuhn); and a septate nonspore- formingfungus w i th a f luffy myce l ium.

Aspergillus flavus was isolated f r o m a fewbroken seeds after harvest in the Gezirascheme. A l i t t le incidence of af latoxin, far be lowthe international ly accepted level , was detectedin these seeds (El Nur et al . 1970).

W e e d s

Many grasses and broadleaved weeds werefound to compete w i th g roundnut in its earlygrowth stages. Accord ing to Ishag (1971) andHamdoun (1976), yield could be reduced by7 3 - 8 0 % i f thef i rs t weed ing were delayed morethan 4 weeks after plant ing.

References

AHMED, K. M., and ELAMIN, T. M. 1976. Minutes of the

International Symposium on Field Pests ofGroundnuts and Millet. The African GroundnutCouncil, 11 Ahmado Bello Road, Victoria, Island,Lagos, Nigeria.

ALI , M. A. 1978. Groundnut rust in the Sudan. A shortpaper submitted to the technical committee of theAgricul tural Research Corporation. No.I.M.I.233179, Kew, England.

AL I , M. A. 1980. Personal communication.

An, M . A . , A G E E B , 0 . A. A.,OMER,H.A.,andAGABENi,A.G. 1970. Report of the Kordofan Agricultural Surveyand Investigation Team. Agricultural Research Cor-poration, Sudan.

BUNTING, A. H. 1954-55. Report of the Tozi ResearchStation, Sudan.

CLINTON, P. K. S. 1960. Seedbed pathogens ofgroundnuts in the Sudan and an attempt at controlwith an artificial test. Empire Journal of Experimen-tal Agriculture. 28: 211-222.

EL NUR, E. and IBRAHIM, G. 1970. Aspergillus flavus and aflatoxin production. Sudan AgriculturalJournal 5: 61.

EL AHMADI, A. B. 1965-66. Annual Report of the Sen-

nar Research Station, Agricultural Research Corpo-ration, Sudan.

ELAHMADI, A. B. 1969-70. Annual Report of the Sen-nar Research Station, Agricultural Research Corpo-ration, Sudan.

HASHIM, A. 1974-75. Annual Report of the Gezira Re-search Station, Agricultural Research Corporation,Sudan.

HAMDOUN, A. M. 1976. Chemical weed control ingroundnuts in the Kenana area of the Sudan. Ex-perimental Agriculture 12: 113-119.

ISHAG, H. M. 1965. The effects of sowing dateon growth and yield of groundnuts in the Gezira.African Soils 10: 509-520.

ISHAG, H. M. 1970. Growth and yield of irrigatedgroundnuts {Arachis hypogaea L.) at different spac-ing in the Sudan Gezira. I. Flowering & yield compo-nents. Journal of Agricultural Science 74: 533-537.

ISHAG, H. M. 1971. Weed control in i rr igatedgroundnuts {Arachis hypogaea L). in the SudanGezira. Journal of Agricultural Science, Cambridge77: 237-242.

ISHAG, H. M., SAID, M. B., KAROURI, A. 0., and SEIF

ELDIN, E. 1980. Effects of land preparation, spacing andphosphorus application on yield of irr igatedgroundnuts {Arachis hypogaea L.) Journal of Ag-ricultural Science, Cambridge (in press).

KHALIFA, 0. 1972-73. Annual Report of the KenanaResearch Station, Sudan.

NUR, I. M. 1976. A new groundnut variety MH.383 forirrigated areas of Sudan. East African Agriculturaland Forestry Journal 41: 294-297.

SAID, M.B.,and MUSTAFA, M. A. 1978. Problemsof soilproductivity under arid and semi-arid conditions ofthe Sudan. Workshop on maximizing soil producti-vity under arid and semi-arid conditions. Oct 23-26,Alexandria, Egypt.

TAHIR, W. M. 1965. Groundnut improvement in theSudan. Experimental Agriculture 1: 225-235.

TAHIR, W. M., and Misovic, M. S. 1967. Agronomicfactors influencing yield and quality of groundnutsin the Sudan Gezira. Experimental Agriculture3: 41-53.

TAR, S. A. J. 1955. The fungi and plant diseases of theSudan. Published by the Commonwealth Mycologi-cal Institute, Kew, Surrey, England.

284

Groundnut Product ion, Ut i l izat ion, ResearchProblems and Further Research Needs in Tanzania

A. Bo l ton*

Product ion

There is a shortage of edible oil in Tanzania duelargely to increased domestic consumption andto some extent to increased emphasis on foodcrops and cash crops. An Oilseeds ResearchProject was started in 1978 with cooperationfrom the British Government Overseas De-velopment Administration. It was based in thesouth of the country but with national respon-sibilities to deal with sesame, sunflower andgroundnut which are the main annual oilseedcrops.

The area under annual oilseed crops(groundnut, sesame, sunflower, castor) isdifficult to estimate, but the Ministry of Agricul-ture estimates give a total of about 150 000 hec-tares of which groundnut accounts for about100 000 ha. Reliable yield figures are not ob-tainable but good groundnut farmers may pro-duce about 700 kg/ha with the traditional peas-ant farmers getting half of this or less.

Mixed cropping is prevalent and groundnutsare nearly always grown in association withother crops. There may be several crops all onthe piece of land with more or less randomplanting of groundnut with cereals (maize orsorghum) etc. It is rare to find fertilizer applied.

Official marketing is carried out by GAPEX(General Agricultural Products for Export) andthe proportion of the crop marketed through theorganization, as shown in Table 1, is only a fraction of total production. There is consider-able domestic consumption by the subsistencefarmer, and most of the surplus is sold throughunofficial channels at a price well above theofficial price offered by GAPEX.

The oil mills in Tanzania have a potential de-mand for 4000 tonnes of groundnut annually

* Agricultural Research Institute, Nallendele, P.O.Box 509, Mtwara, Tanzania.

(out of a total requirement for all oilseed cropsof over 200 0001) but supplies are considerablybelow this figure, although if the estimate of100 000 ha under groundnut is anywhere nearreliable, the quantity needed by the mills is stillonly a small fraction of thetotal production. Theprice offered by GAPEX is at present Shs.4.00/kg(approximately Rs 4) but the unofficial price canbe several times higher, particularly in the largeurban centers.

Research

A good deal of work has been carried out in thepast in Tanzania especially in the years im-mediately after the second world war when theBritish Government started a large scale pro-duction scheme based at several centers in thecountry. This scheme was not successful. Sincethen, work has included a number of varietytrials run within the network of research sta-tions administered by the Crop Research Divi-sion of the Ministry of Agriculture. Between the1969- and 74-75 seasons, 28 trials tested 118entries but the trials were not coordinated andjoint analysis has proved impossible.

Many of these entries were collections oflocal material largely from the north-west areaof Tanzania collected by Ukiriguru. The exactorigin is not always clear, but they are classifiedmainly as upright bunch with a fewdescribed asspreading, although none appear to be ofpurely Virginia or runner habit. In the cropsgrown by local farmers in the south, a smallnumber of plants of runner habit may be foundin the crop.

The Oilseeds Research Project which startedin 1978, aimed primarily at breeding and theagronomy of sesame and sunflower. However,in view of the importance of groundnut to thepeasant farmer, groundnuts were includedwith the intention of sorting out the varietal

285

position as far as possible, and of conductingagronomic experiments with the more promis-ing entries. Standard varieties in the collectionincluded Natal Common, Sigaro Pink, RedMwitunde and Makulu Red but the purity ofthese named entries and of those in the localcollection is so doubtful that no single namedvariety in the country prior to 1978 can be ac-cepted as entirely valid.

During the past two seasons, samples ofsome named varieties and of breeding material

have been received from other countries includ-ing the United States and India (ICRISAT), to-gether with some local types from the Lindi andMtwara Regions in the south of Tanzania. Atpresent they areundergoing multiplication andwill be tested in trials as sufficient stocks of seedbecome available.

Results of yield trials carried out at four sitesin 1978-79 are presented in Table 2. Entriesidentified by numbers are those from theUkiriguru collection and the indications are that

Table 1. Marketed groundnut p roduct ion In Tanzania.

Marketed production(tonnes) Exports (tonnes) Mtwara Dodoma Tabora

Region(%)

Region(%)

Region(%)Year Totala Groundnut Totala Groundnut

Region(%)

Region(%)

Region(%)

71-72 30 598 3295 27 686 7572-73 30 497 3454 20 733 232 38 35 2273-74 19 874 1363 9 265 Nil 29 7 4674-75 16 733 509 9 702 Nil 48 - 5

75-76 15 489 510 2 259 Nil 55 5 -76-77 14 157 417 3 000 Nil 50 14 -77-78 17 437 1448 6 669 Nil 61 23 -78-79 b 22 787 2615 _ — 52b 2b 16*

a. Total Is figure for sesame, castor, sunflower, and groundnut.b. Purchases to April 1979.

Table 2 . Groundnut variety t r ia ls 1 9 7 8 - 7 9 ; kernel y ield (kg/ha) .

Variety Nachingwea Naliendele Suluti Mtopwa Mean

69.62.2.5 1538 1516 1169 1146 134270.1.1.1. 1468 1710 1215 955 133769.63.2.5 1577 1463 1271 1028 133569.17.6 1633 1610 1218 792 131369.358.1.4a 1596 1450 1208 863 127969.29.2 1535 1613 1124 839 1278

69.15.3 1605 1320 1204 756 1221Natal Common 1227 1315 1277 1007 120769.99.1.2.4 1237 1473 1069 940 118070.7.3. 1387 1331 1208 748 116969.17.1 1345 1505 960 850 1165Sigaro PinK 1122 623 874 471 773

Mean 1439 1411 1150 866 1217S.E. 1019 102.0 106.9 116.7 54

a. 68.35a. 1.4 Is Natal Common ex. Ukiriguru.

286

adequate yields can be obtained under reason-able conditions.

Tables 3 and 4 give results from last seasontesting at six sites which were much the same asentries in the previous season. The main con-clusion is that groundnut can be successfullygrown over a fairly wide range of climatic condi-tions. Next season, 1980-81, some introduc-tions will be tested extensively.

Yields of some introductions are encourag-ing, e.g., Tifspan did well in a multiplication plotlast season. It is hoped to run trials at up to 20sites to arrive at reliable performance data.

A few agronomy trials were carried out lastseason. One plant population trial (Table 5) in-dicated that populations of up to 250 000 plantsper hectare gave increasi ngly higher yields. Thedifficulty is the large amount of seed requiredfor planting which the peasant farmer does nothave available. The variety used last seasonwas one of the local entries.

A similar trial in the 1978-79 season usingSigaro Pink showed that spacing between rowsof 60 cm is probably too wide. The present re-commendations for crops in southern Tanzaniais 50 cm x 10 cm giving 200 000 plants per hec-tare.

A start was made on intercropping trials withresults as in Tables 6 and 7. The aim was tocompare rows of cereal, maize or sorghum in-terspersed with 1, 2, or 3 rows of groundnut.

Table 3. Groundnut var iety t r ia ls 1 9 7 9 - 8 0 ; karnal y ie ld (kg/ha) .

Variety Ndengo Suluti Utengule Mtopwa Mean

69.62.2.5. 903 798 808 1600 102769.15.3 1005 584 967 1520 101970.1.1.1. 1190 514 696 1600 100069.99.1.2.4 935 770 879 1300 97169.29.2 855 818 866 1140 920

69.63.2.5 880 484 788 1460 903Natal Common 1013 790 861 - 88869.35a. 1.4 827 588 467 1560 86169.17.6. 834 610 867 1120 858Local - 280 409 - 345

Mean 938 624 761 1412S.E. 76.6 71.6 94.8 -

Note: Last two replications of the Mtopwa trial were not enalyzed. Data presented above Indicate yield levels attainable.Naliendele and Nachingwea results are shown in Table 4.

Last season was exceptionally difficult with a pronounced drought for 4 weeks from about 2 weeks after planting. The yields obtained aretherefore not unsatisfactory. There was a definite advantage from the intercropping sys-tem at one site (Naliendele) but not at the other(Nachingwea). Spacing of sorghum and

Table 4. Groundnut variety t r ia ls 1980; kernely ie ld (kg /ha) .

Variety Nachingwea Naliendele Mean

69.63.2.5. 2228 1502 186569.1.5 2114 1331 172369.29.2 1922 1463 169369.99.2.4 2070 1270 167069.17.6 1798 1525 1662

69.62.2.1. 1782 1516 1649Natal Common 1808 1422 161569.62.2.5 1742 1429 158670.1.1.1. 1968 1196 158269.17.2 1772 1301 1537

69.15.3 1854 1218 153669.35a. 1.4. 1650 1356 1503Local 2198 404 130169.35.1. 1136 1234 1185Sigaro pink 1388 576 982Red Mwitunde 1160 439 800

Mean 1787 1199 1493S.E. 131.4 67.6

287

groundnut was 50 cm x 10 cm and of maize,50 cm x 50 cm. These agronomy trials will becontinued next year.

Pests and DiseasesNo specific research work was conducted andthe following brief notes are records from themain center, Naliendele.

Table 8. Groundnut plant populat ions,Naliendele, 1979-80.

TreatmentTreatment

Spacing (cm) Plants/ha (kg/ha)

1 60 x 40 41667 11384 40 x 40 62 500 12332 60 x 20 83 333 12765 40 x 20 125 000 14753 60 x 10 166 667 14206 40 x 10 250 000 1783

S.E. 53.1

Insects Observed

GROUNDNUT APHID (APHIS CRACCIVORA). Thesewere observed giving rise to rosette virus butnot in large numbers. The number of plantsaffected was small. The disease has been re-ported often in Tanzania but the true effect ofthe virus on the crop is not known with anycertainty.

BEAN WEBWORM (LAMPROSEMA INDICA). A

tle damage was caused.lit-

SPOTTED BORER (MARUCA TESTULAUS). These

Tabla 6. Intareropping groundnut/maize, Nachingwaa, 1979-80.

Crop valueTreatment LER (Sh./ha)

Maize pure 4269Groundnut pure 6469Intercropped maize/groundnut 1:1 1.24 6760Intercropped " " 1:2 0.87 5104Intercropped " " 1:3 1.04 6075

S.E. 0.110 546

Mean yield pure stand maize 4270 kg/hagroundnut 1617 kg/ha

Tabla 7. Intercropping groundnut/sorghum, Naliendele, 1979-80.

Treatment LERCrop value

(Sh./ha)

Sorghum pureGroundnut pureintercropped sorghum/groundnut 1:1Intercropped " " 2 :2Intercropped " " 1:3

S.E.

Mean yield pure stand sorghumgroundnut

1.781.811.940.100

1893 kg/ha639 kg/ha

18932566380037504335

320.9

288

were present in considerable numbers duringthe two seasons.

AMERICAN BOLLWORM WEUOTHIS ARMIGERA).

Considerable numbers of these caterpil-lars were found feeding on the leaves and in1980 there was noticeable damage after flower-ing. They were also present on sunflower headsand sorghum in adjacent plots.

COTTON LEAFWORM (SPODOPTERA UTTORAUS).

Small numbers of the caterpillars were foundfeeding on the leaves.

TOBACCO WHITEFLY (BEMISIA TABACI). This was

occasionally found in small numbers suckingthe underside of groundnut leaves.

GROUNDNUT HOPPER (HILDA PATRUELIS). A

few scattered plants were attacked by this insectwhose nymphs and adults suck from the base ofthe plant under the soil surface. Attacked plantswilted and died.

LEAF BEETLE (CYPONYCHUS SPP). Some adultbeetles were found eating from the leaf surfaceleaving irregular patterns on the leaves.

FLOWER (POLLEN) BEETLES (MYLABRIS SPP AND

CORYNA SPP). These beetles were common onthe groundnut flowers in both seasons.

TERMITES. Nearly always found somewhere.

Diseases Observed

ANGULAR LEAF SPOT {CERCOSPORA PERSONATA

AND C. ARACWDICOLA). This disease wascommon in plants which had nearly completedflowering. It was therefore not so serious as tocall for control measures.

RAPID YELLOWING OF WHOLE PLANT. In the

1980 crop, there was a severe yellowing ofplants in most plots around the Institute (but notin the experimental field) and on experimentalplants at one subcenter.

The following fungus species were identifiedfrom root and stem selections: Curvularia lunata; Fusarium spp; and Botryodiplodia theobromae.

Root and stem sections showed brown dis-coloration on the conducting tissues. The podswere also infected.

289


in Z imbabwe

G. L. Hi ldebrand*

Zimbabwe is situated between 16° and 22°Slatitude and varies in altitude from 160 m to2000 m. Zimbabwe is part of the plateau whichtraverses the subcontinent of Africa. This cen-tral plateau, known as the Highveld extends forsome 650 km in a south-west to north-eastdirection. The rainfall is generally adequate tosupport a broadly based agricultural industryand the bulk of the country's development isconcentrated in this area.

On either side of the central plateau lies theMiddleveld where altitudes range from 600 to1200 m. Below 600 m lies the Lowveld wherehot and generally drier conditions prevail. Themain cropping area lies between 300-1600 m,although cropping is largely dependent on irri-gation below 800 m.

The climate is characterized by definite wetand dry seasons, with the wet season beginningin November and ending in late March. Someclimatic data for selected sites at a range ofaltitudes in Zimbabwe are given in Table 1.

Product ion

The groundnut crop is small by world standardsbut is an important source of food in the ruralarea and surpluses are an important cashearner.

No accurate production figures are availablebut estimates and sales for the 1978-79 and1979-80 seasons are given in Table 2. Thesefigures show that more than 90% of groundnutproduction comes from the rural areas and thatthis sector retains about 90% of its productionfor local use. Groundnuts are a controlled pro-

• Groundnut Breeder, Crop Breeding Institute, De-partment of Research and Specialist Services, P.O.Box 8100, Causeway, Zimbabwe.

duct in Zimbabwe and must be sold through theGrain Marketing Board or its agents.

Estimated deliveries to the Board have beenof the order of 15 000 to 20 000 tonnes annuallyin recent years. Before the war in Zimbabweannual deliveries were about 30 000 tonnesandhave now reached 44 000 tonnes.

The irrigated crop that consists of long sea-son varieties grown in the large scale farmingarea, yields about 50% confectionery nuts ofwhich about 75% are exported. The small-kernelled short season varieties (Spanish andValencia types), that are grown under drylandconditions in the rural areas, yield about 25%confectionery nuts of which about 60% are ex-ported. Crusher grade accounts for 65% of thedryland crop while about 10% is used for seed.

With peace returningtothecountry, and withit, improved availability of inputs, better com-munications and transport, and easier market-ing, it is estimated that annual deliveries arelikely to increase to about 30 000 tonnes in thenear future.

A large increase in area planted is unlikely tocome about in the foreseeable future and there-fore it is doubtful whether further increases indeliveries will occur unless there are significantincreases in yield.

Variet ies and Product ion Methods

There are two main types of varieties grown. Thelong season varieties (mainly of Virginia botani-cal type), depending on altitude, mature in140-200 days and are generally only suited toproduction under irrigation where planting canbe carried out before the onset of the rains.These varieties are planted from late-September to mid-October and are harvestedfrom late-March to mid-April. The ability to plantearly with irrigation has resulted in theachievement of high yields (Metelerkamp

290

1967). The highest yield achieved to date on a field scale is 9.6 t/ha unshelled.

The short season varieties (Spanish andValencia botanical types), depending on

altitude, mature in 110-150 days and are usu-ally grown under rainfed conditions but haveproduced promising yields when grown underirrigation in the warmer areas.

Table 1. Some c l imat ic data fo r selected sites in Z imbabwe (means fo r 5-month periodNovember—March).

Meteorological station (with altitude in m)

Marandellas Gatooma Tuli Triangle1628 1157 765 421

Mean max. temperature (°C) 24.4 28.4 30.4 32.2Mean min. temperature (°C) 14.2 17.0 17.9 19.3Mean hours sunshine/day 6.5 6.8 7.3 7.3Mean evaporation/month (mm) 152 175 198 200Duration of rainy season (days) 135 125 80 105Rainfall for Nov-Mar (mm) 840 706 394 539Annual rainfall (mm) 936 776 455 622Annual rail fall (mm) 936 776 455 622

Table 2. Groundnut product ion in Z imbabwe (unshelled groundnuts ; Crop Forecast Commit teeestimates).

Season Source

Areaplanted Yield Production Retention Deliveries

(ha) (t/ha) (tonnes) (tonnes) (tonnes)

1978/79 Large-scale farming areas- irrigated- dryland

Small-scale farming areasRural areas

1 5001400

3.331.43

5 000 2 000

Large-scale farming areas- irrigated- dryland


2 900 7 000 250 6 750

1978/79



12 000 240 000

0.580.42

7 000100 000

2 00091 750

5 000 8 250



252 000 107 000 93 750 13 250

Total 254 900 114 000 94 000 20 000

1979/80 Large-scale farming areas- irrigated- dryland


2 2001400

3.501.64

7 7002 300



3 600 10 000 300 9 700

1979/80



11 000360 000

371 000

0.540.31

6 000 110 000

116 000

5 000 100 700

105700

10009 300

10 300

Total 374 600 126 000 106 000 20 000

291

Although good yields have been achieved byefficient producers the national average yieldsare disappointingly low.

In recent years a close relationship betweenweather and yield has become evident (Wil-liams, Hildebrand and Tattersfield 1978). Theinfluence of radiation and temperature on finalyield is illustrated in Figure 1 for two shortseason varieties grown in variety trials at Salis-bury Research Station over a period of 12 years.

An interaction with environment has alsobecome evident in which Valencia varietiestend to yield more in the cooler, high altitudeareas while the Spanish types tend to yieldmore than Valencia types in the warmer andgenerally drier areas.

The influence of altitude, and therefore temper-ature, on the mean yields and gross returns ofthese two varieties at 11 sites over a number ofyears is illustrated in Figures 2 and 3.

ResearchThe bulk of the research effort in the pastdecade has been placed on variety improve-ment (Hildebrand 1975a), physiology andgrowth analysis. This effort has resulted in a number of varieties being made available forcommercial production (Department of Re-search and Specialist Services 1979) and a verysignificant contribution has been made to theunderstanding of groundnut growth undervarying climatic conditions.

Radiation (22-41 days) + Mean maximum temp. (°C)(December + February + M8rch)

Figure 1. The relation between yield and weather for two groundnut varieties grown at Salisbury Research Sta-tion.

Some work on the agronomic aspects ofgroundnut production was conducted in thesixties and early seventies and has resulted inthe basis for recommendations for productionin the large scale farming area (Collett 1973).These have also provided principles on which tobase recommendations for production in therural areas. However, certain problems stillexist which are limiting yields and for whichsolutions must be sought. These are dealt within more detail in the section under FurtherResearch Needs.

Variety Improvement

Long-Season Varieties

Breeding and selection continues to develop

Altitude (m)

Figure 2. The relation between yield and al-titude for two groundnut varieties.

Figure 3. The relation between gross return and altitude for two groundnut vari-eties.

292

improved varieties for production under irri-gation. Table 1 shows that the irrigated crop,that is largely grown in the large scale farm-ing area, is small but it is nevertheless importantas the high yields and good quality nuts pro-duced are a valuable earner of foreign exchangewhen exported for confectionery. Objectivesare to improve yield potential, kernel size andkernel quality. Considerable emphasis has beenplaced on selection of varieties with a pale pinktesta since world markets for red-skinned va-rieties are limited. This had led to the develop-ment of the variety Egret which is now the mainvariety grown (Hildebrand 1975c). Selection willcontinue for higher yields, better quality andimproved agronomic aspects such as diseaseand pest resistance, strong peg attachment andacceptable shelling characteristics (Hildebrandand Smartt 1980).

Short-Season Varieties

HIGH ALTITUDE AREAS. Many of the Valenciatypes collected in the country and introducedfrom elsewhere are red-skinned. Because of thelimited market for red-skinned groundnuts in theconfectionery trade, considerable emphasishas been placed on the selection of pink-skinned Valencia varieties or varieties with ac-ceptable testa color that yield well in the highaltitude areas.

The red-skinned Valencia R2 was released in1974 (Department of Research and SpecialistServices 1974). This variety was introducedfrom Dr. W. C. Gregory's South American col-lection and has given high yields and showssome tolerance to Cercospora arachidicola. A number of promising pink Valencias and othervarieties which are adapted to the higher al-titude areas are in advanced stages of varietytesting at this time. Promising results have beenshown by locally bred varieties, some arisingfrom infraspecific crosses.

The past season's results indicate toleranceto drought, improved kernel size and qualityand the presence of seed dormancy in some ofthe locally bred selections.

Low ALTITUDE AREAS. Natal Common hasbeen grown in these areas for many years. It is a small-kemelled Spanish variety with a light pinktesta. Considerable effort in the past decade hasbeen placed on the selection of similar varieties

with improved yield, kernel size and kernelquality. It was felt that under conditions oflimited rainfall, it will be difficult to make sig-nificant increases in yield but that superiorkernel size and quality could result in greaterreturns to the producer through better gradesand greater value in the confectionery market.

A Spanish type, Jacana, having superioryield, kernel size and market quality, was re-leased in 1975 (Hildebrand 1975b). This varietyhas, however, recently been withdrawn becauseof difficulties experienced in shelling.

A number of varieties in advanced stage oftesting have shown promise including somealready mentioned from locally bred selectionswhich appear to be adapted to a wide range ofaltitudes.

Dwarf Genotypes

Extreme rank growth has been experiencedwith long and short season varieties whengrown at low altitudes under irrigation.Branches often reach 1.5 m or more in lengthand represent an apparent waste of photo-synthate in producing excess vegetativegrowth.

Selection for genotypes with short staturehas led to encouraging results with lines whichhave stems of only 0.5-0.8 m in length.

Disease Resistance

Sources of tolerance to Phoma arachidicola have been included in crosses and selectionfrom segregating populations and progenies iscurrently being undertaken.

Some breeding and screening for rust resis-tance has been carried out. Three of the FESR Falines were used as parents in crosses but nomajor emphasis has been placed on this workas serious rust occurs only in the low altitudeareas. It is not likely to become as economicallyimportant as the leaf spot diseases.

One source of tolerance to Cercospora arachidicola has been used in some crosses.Some fairly promising selections from a crossbetween this Valencia line and a long seasonline are in variety trials.

Shelling Abi l i ty

The marketing policy in Zimbabwe is to encour-

293

age delivery of unshelled pods for centralizedshelling by the Grain Marketing Board. There isa specific requirement therefore for varietiesthat can be suitably shelled since although a small proportion of the crop is marketed, thatportion is however valuable, and it must bepossible to carry out efficient shelling.

Jacana is one variety which shells very poorlywhen grown under difficult conditions of har-vesting and curing. For this reason routinescreening of shelling ability of all varietiesentered into variety trials is now carried outusing a Dawson Model 3 groundnut shelter(Davidson and Mcintosh 1973). Considerabledifferences have been noted between varietiesbut the poor shelling results of Jacana underfield scale production has not been found inJacana grown in variety trials.

D isease C o n t r o l

Research on the epidemiology of leaf spot andpod rot fungi has been carried out over the pastdecade (Cole). Leaf spots caused by Cercospora arachidicola and Cercosporidium personatum are well controlled by the recommendedmancozeb/benomyl mixture. Good control hasalso been achieved with chlorothalonil. Phoma arachidicola is more difficult to control withchemicals. It has been found that C. arachidicola is antagonistic toward P. arachidicola and com-plete chemical control of C. arachidicola re-sults in severe infection by P. arachidicola.

Delaying the start of a chemical disease con-trol program, to allow a low level of C.arachidicola to develop, generally results in a low and balanced level of both pathogens.Efficient control of foliar diseases results inreduced losses caused by pod rots and podshedding.

Depressed yields due to chemical diseasecontrol have been experienced under condi-tions of limiting moisture. For this reason spray-ing of dryland crops is generally not recom-mended.

Encouraging results have been achievedusing spinning disc ULV sprayers and thesecould be of considerable benefit on irrigationschemes in the rural areas.

Aspergillus flavus appears to occur in sig-nificant levels only in those years where a midseason dry spell is experienced duringJanuary or February.

Rosette virus is of economic importance only inthe rural areas when plant stands are thin.

P h y s i o l o g y a n d G r o w t h A n a l y s i s

A very significant contribution has been madeto the understanding of groundnut growth inthe past decade (Williams, Wilson and Bate1976; Williams 1979a, b, c, d, e). This has shownhow groundnuts respond to the environmentand how different varieties are affected bydifferences in climate (Williams, Wilson andBate 1975; Williams and Allison 1978).

A g r o n o m y

Research on plant populations, spacing,and early planting with irrigation have madesignificant contributions to increased produc-tion (Metelerkamp 1967). In additon the work onphysiology and growth has contributed to-wards better agronomic practice, particularly inthe irrigated crop.

M e c h a n i z a t i o n

Investigation into mechanization of groundnutproduction has resulted in expansion ofmechanized harvesting and curing of the irri-gated crop plus development of picking andcleaning aids for small scale producers. Investi-gations into drying methods, including the use ofsolar energy, have been conducted (Oliver1978).

W e e d C o n t r o l

Screening of chemicals for, and methods of,weed control have continued and have resultedin chemical weed control recommendationswhich are widely used in the irrigated crop(Borland 1973 and 1975).

A f l a t o x i n

During the sixties and early seventies, a surveyof the incidence of aflatoxin in the national cropwas conducted. This work led to the establish-ment of a monitoring procedure for aflatoxin foruse by the Grain Marketing Board (Du Toit 1971)and established the environmental conditionswhich would influence the incidence of Asper-gillus flavus damage in the national crop.

294

N u t r i t i o n A g r o n o m y

Limited research on nutrition of groundnuts onpoor soils in the rural areas has shown largeresponses to the application of manure, manureand gypsum, and phosphates. Application ofphosphate and sulphur are most important. Thefertilizer recommend ations as made by fertilizeradvisory services for large scale farming areasdo not apply since the residual fertility in therural areas is very low. It is felt that groundnutscould play an important part in the improve-ment of general fertility practices in the ruralareas since large applications of nitrogen arenot required and the good monetary returnsfrom the groundnut crop are likely to betterstand the cost of increased fertilizer applicationthan many other crops.

Responses to Rhizobium inoculation havebeen small since there are naturally occurringRhizobia in most soils.


V a r i e t y I m p r o v e m e n t

This must be continued and expanded with theobjective of developing new varieties, particu-larly for the rural areas, which have: improvedyield and quality; drought tolerance; diseaseand pest resistance; seed dormancy at harvest;reduced vegetative growth for those areaswhere rank growth occurs; and satisfactoryshelling quality when grown under difficult har-vesting and curing conditions.

D isease C o n t r o l

Research should continue with regard to:epidemiology of the economically importantdiseases; screening of chemical control mea-sures; cost and efficiency of chemical controlmethods; and feasibility of foliar disease con-trol in the dryland crop.

Pes t C o n t r o l

Hilda patruelis has been a problem in the past inthe large scale farming area, particularly in dryseasons. It could well be a problem in the ruralareas. Further research on the biology andcontrol of this pest is necessary.

It is generally accepted that the technology forincreased groundnut production is available.The greatest need now is for an expansion ofthe extension effort.

There are, however, certain problem areas theextent of which are not known and it is felt thatthese should be investigated as early as possi-ble. These problem areas include: (1) methodsof facilitating earlier planting. Lack of draught isthe greatest limiting factor to being able toplow and plant as early as possible after thefirst rains. Although it may not facilitate earlyplowing, water-planting ahead of the rainsmay enable the producer to best use residualmoisture and favorable early season radiationand temperature; (2) the effect of nematodes ongroundnut crops is not well known. Some effortshould be made to establish if it is in fact a problem.

N u t r i t i o n

Further research is needed to provideguidelines for fertilizer applications in the ruralareas with particular reference to: basal fer-tilizer recommendations; the timing of gypsumapplications since it is likely that gypsum will bea more important source of sulphur than cal-cium; and levels of starter nitrogen requiredand whether benefits would accrue from theuse of Rhizobium inoculant since groundnut inthe rural areas are not, as a rule, inoculated.

Re fe rences

BORLAND, T. M. 1973. Weed control systems forgroundnut and soyabeans. Rhodesia AgriculturalJournal 70: 162.

BORLAND, T. M. 1975. Weed control in oilseed crops.Rhodesian Farmer 46: 15, 25.

COLE, D. L. Diseases of groundnuts (Arachis hypogaea L.) 1. Fungicide spray effects on Cercospora arachidicola and Phoma arachidicola leaf infection,kernel yield and pod rots. (Submitted for publicationin Zimbabwe Journal of Agricultural Research).

COLLETT, W. E. 1973. Oilseeds Handbook. Departmentof Conservation and Extension, Salisbury, Zim-babwe.

295

DAVIDSON, J. I. and MCINTOSH, F. P. 1973. Development

of a small laboratory shelter for determining peanutmilling quality. Proceedings of the American PeanutResearch Education Association 5(1).

DEPARTMENT OF RESEARCH AND SPECIALIST SERVICES.

1974. Release of Valencia R2 groundnut. RhodesiaAgricultural Journal 71: 129.

DEPARTMENT OF RESEARCH AND SPECIALIST SERVICES.

1979. A description of crop varieties released by theDepartment of Research and Specialist Services.Supplement to Zimbabwe Rhodesia AgriculturalJournal 76, 1979.

DOTOIT, A. A. 1971. Safety standards for aflatoxins inRhodesia. Rhodesia Agricultural Journal 68: 67.

HILDEBRAND, G. L. 1975a. Groundnut variety im-provement in Rhodesia. Workshop on germplasmpreservation and genotype evaluation in peanuts.July 12-15,1975. University of Florida, Gainesville,Florida, USA.

HILDEBRAND, G. L. 1975b. Jacana groundnut — cropvariety release notice. Rhodesia Agricultural Jour-nal 72: 153.

HILDEBRAND, G. L. 1975c. Egret groundnut — crop var-iety release notice. Rhodesia Agricultural Journal72: 154.

HILDEBRAND, G. L, and SMARTT, J. 1980. The utilization

of Bolivian groundnut (Arachis hypogaea L.)germpiasm in Central Africa. Zimbabwe Journal ofAgricultural Research 18: 39.

M ETERLERKAMP, H. R. A. 1967. Response to early plant-ing and irrigation of a late maturing groundnut vari-ety. Rhodesia Agricultural Journal 64: 127.

OLIVER, G. J. 1978. Report of oilseeds mechanizationinvestigation. Institute of Agricultural Engineering,Department of Conservation and Extension, Salis-bury, Zimbabwe.

WILLIAMS, J. H. 1979a. The influence of shading duringthe pre-flowering phase of groundnuts {Arachis

hypogaea L.) on subsequent growth and develop-ment. Rhodesia Journal of Agricultural Research17: 31

WILLIAMS, J. H. 1979b. The physiology of groundnuts(Arachis hypogaea L. cv. Egret). 1. General growthand development. Rhodesia Journal of AgriculturalResearch 17: 41.

WILLIAMS, J. H. 1979c. The physiology of groundnuts{Arachishypogaea L. cv Egret). 2. Nitrogen accumu-lation and distribution. Rhodesia Journal of Agricul-tural Research 17: 49.

WILLIAMS, J. H. 1979d. The physiology of groundnuts{Arachis hypogaea L. cv Egret). 3. The effect of thin-ning at different stages of development on repro-ductive growth and development. Rhodesia Journalof Agricultural Research 17: 57.

WILLIAMS, J. H. 1979e. The physiology of groundnuts{Arachis hypogaea L. cv. Egret). 4. The growth ofgroundnut fruit set at the start and end of pod set-ting. Rhodesia Journal of Agricultural Research17: 63.

WILLIAMS, J. H., and ALLISON, J. C. S. 1978. Genetic

differences in the growth of groundnuts {Arachis hypogaea L.) pods and kernels. Rhodesia Journal ofAgricultural Research 16: 73.

WILLIAMS, J. H., WILSON, J. H. H., and BATE, G. C. 1975.

The growth of groundnuts {Arachis hypogaea L.) atthree altitudes in Rhodesia. Rhodesia Journal of Ag-ricultural Research 13: 313.

WILLIAMS, J. H., WILSON, J. H. H., and BATE, G. C. 1976.

The influence of defoliation and pod removal ongrowth and dry matter distribution in groundnuts(Arachis hypogaea L. cv Makulu Red). RhodesiaJournal of Agricultural Research 19: 241.

WILLIAMS, J. H., HILDEBRAND, G. L, and TATTERSFIELD,

J. R. 1978. The effect of weather andgenotype x environment interaction on the yieldsof groundnuts (Arachis hypogaea L) . RhodesiaJournal of Agricultural Research 16: 193.

296

Session 8 — Country Reports

Discussion

P. SubrahmanyamYou mentioned that both rust and leaf spotsare important in Malaysia and that you wereusing benomyl as a fungicide. How are yougoing to control rust as benomyl will onlycontrol leaf spots? Secondly, what is the rangeof aflatoxins in Malaysian peanuts?

H. B. HamatRust came to Malaysia only recently and so faris not a threatto groundnut cultivation. We arepresently controlling leaf spots with benomyland will have to change fungicides if rustbecomes serious. Aflatoxin levels in Malay-sian groundnuts have not been determined.

R. P. ReddyYou state that in Malaysia lime is applied at therate of 1 tonne/ha. What sort of lime do youapply and is it to supply calcium or to changethe soil pH?

H. B. HamatI am not sure what the source of lime is, but itis to combat the low pH of Malaysian soils,which are very acidic.

R. O. HammonsYou mentioned that peanut is boiled in theshell in Malaysia. In what form is it eaten — asthe seeds or the whole fruit? In Bolivia youngboiled fruits are eaten whole.

H. B. HamatOnly the seeds are eaten in Malaysia.

R. W. GibbonsDo you manufacture your own Ultra LowVolume (ULV) spraying equipment inAustralia?

K. MiddletonAt present we are importing ULV or CDA(Controlled Droplet Application) equipmentfrom the United Kingdom. But a subsidiary

company in the USA is now manufacturingthis equipment on a large scale and thisshould be available on a large scale shortly.

S. M. MisariThe pattern of plants wilting that you showedin one of your slides indicated that the affectedareas were scattered through the field, and yetthe field showed no obvious depressions.Have you investigated the soil properties, andhave you checked for soil pests in these wiltedareas?

K. MiddletonWe have obtained negative results for soilpests and nematodes in these wilted patches.We feel that these patches are the result ofchanges in the physical structure of the soilscaused by intensive cropping and machinecompaction over the years.

J. S. ChohanYou have mentioned that leaf spot and rust arecontrolled in Venezuela by fungicides. Whatfungicides do you use, and what costs areinvolved?

B. MazzaniThe most important disease is leaf spot. Rust ispresent every year, but only occasionallydoes it'become serious, say every fifth or sixthyear. Benlate is commonly used to controlleaf spot, but many sprays are used and it is themost costly of all the inputs. One farmer toldme recently that he spent up to US$ 250 perhectare on leaf spot control.

P. J. DartI was surprised to hear that you used 1 tonne/ha of a 6:12:6 compound fertilizer ongroundnuts in Venezuela. This means that youare applying 60 kg of nitrogen. Do your experi-ments show the need for so much nitrogen?The implication is that the nodule nitrogenfixing system is not working effectively and

297

would warrant some microbiological re-search.

B. MazzaniThe soils in the groundnut growing regionsare very poor and contain practically no nitro-gen. Experiments show that this amount offertilizer is required, and this question of highfertilizer usage in Venezuela is often askedbecause it is so unusual.

Vikram SinghIn Venezuela there has been a significantincrease in yield, from 700 kg/ha in 1972 toover 1800 kg/ha in 1979. How have these largeincreases come about?

B. MazzaniNot all the factors that have contributed to thisincrease have been analyzed, but I would thinkthatthe most significant singlefactor has beenthe increase in the area under irrigation.

A. S. ChahalBreeding is under way in Brazil for resistanceto Aspergillus flavus but what about A nigerl Is this fungus also a problem?

A. S. PompeuAspergillus niger is at present only a minorproblem in Brazil. The most important of alldiseases is leaf spot.

K. MiddletonI would like to inform the delegates thatbesides Brazil, there is an interest in the use ofunrefined groundnut oil to power diesel en-gines at the James Cook University inTownsville, Queensland. Groundnut oil hasbeen used as fuel in a diesel engine, and itproved to be competitive with normal dieselfuel.

J. S. SainiI would like to ask the speaker from Malawi tocomment on weed control in that country. Weheard that weeds, particularly grassy weeds,are a real problem there and cause large yieldreductions.

C. KisyombeGenerally, the weed problem is still tackled bymost farmers in the traditional way —by

using the hand hoe or by hand pulling tallweeds. There has been some success with the"Lasso" brand preemergence herbicide on a research basis, and herbicides will be used bylarge growers.

T. P. YadavThe average yields obtained by farmers inMozambique are very low — around 200 to500 kg/ha. What are the highest researchyields obtained?

A. D. MalithanoDuring colonial times very little research workwas done on groundnuts as it was not a majorexport crop, so it was largely ignored. Thecurrent research program has only just startedand our first results gave us yields around 700to 900 kg/ha; but we are sure we can improveon these figures, particularly if we usesupplementary irrigation.

J. S. ChohanWhat is the current staffing pattern forgroundnut research in Mozambique?

A. D. MalithanoMany scientists left Mozambique after inde-pendence in 1975. At present I am the plantbreeder, and there is an FAO expert who has todivide his time with several other crops. Wehope shortly to recruit an agronomist and a pathologist.

J. S. ChohanThe extension agency in Mali seems to be veryeffective. Would you care to elaborate on this?

D. SoumanoWe have separate extension and researchunits. Thedetailed data from research findingsare handed overto the extension agency. Theyare well-equipped with extension aids to carrythe information to the farmers. Research re-sults are only carried to the farmers via exten-sion workers, never directly.

P. W. AminTermites appear to be important pests in Mali.Are they more troublesome as field pests orstorage pests? What control measures areused?

298

D. SoumanoMost of the problems by termites are causedin the field, even before harvest. At present,Furadan is being used to control termites.

Vikram SinghWhat are some of the morphological featuresand/or physiological traits identified by theworkers in Senegal that impart drought toler-ance or resistance?

J. GautreauFrom our studies morphological characters donot appear to be important. Two cultivars, onedrought resistant and the other not, can havevery similar morphological characters. Wefound differences between cultivars when wemeasured transpiration rate, stomatal resis-tance, and leaf water potential.

Vikram SinghIn the fungicide trials in Zimbabwe you some-times got a depression in yield. Can you offeran explanation?

G. HildebrandWe have not got enough data on this, but wesuspect that in dry years the treated plantsretain their leaves and lose too much water,whereas the untreated plants have lost someof their leaves due to disease and can with-stand the dry conditions.

K. MiddletonWe have had similar experiences in Australia.The fungicides we use (chlorothanonil andfentin hydroxide) seem to affect the physi-ology of the plant even when diseases are notprevalent. They help to delay maturity and theplants may wilt if sufficient water is not avail-able in heavily sprayed plots.

D. V. R. ReddyIs 'clump' virus economically important inSenegal? Is rosette still important?

J. GautreauIn Senegal 'clump' is present but in verylocalized small pockets. It is not economicallyimportant as yet but it has a very spectaculareffect on the plant.

Rosette is more important in the south ofSenegal. A new resistant variety (69-101) has

been released, and where it is grown, rosetteis no longer a problem.

R. W. GibbonsThe world record commercial yield of over 9 tonnes/ha was achieved a few years ago inZimbabwe. Under what production practiceswas this yield obtained?

G. HildebrandThe yield of 9.6 tonnes/ha was achieved in1973-74 in a comparatively dry year in theBulawayo region. The farmer planted early, hefollowed an irrigation schedule and used ben-late and mancozeb for disease control. He didhowever use about twice the recommendedplant rate per hectare but he repeated theseyields over the next two seasons with thenormal rates of 1.25 to 1.5 million plants/ha. Heobtained these yields with the Makulu Redcultivar over an area of 30 acres.

D. R. C. BakhetiaIn one of the slides during the presentationfrom Nigeria we saw stunted growth in onetrial that resulted from the effect of a fungicide.What was the fungicide?

C. HarknessI would prefer not to disclose the name of thefungicide, which was an experimental formu-lation. We grew groundnut the next season onthe same area and the residual effects wereclearly apparent on the plots that had beentreated with this chemical.

D. H. SmithI obtained similar results with an experimentalformulation, perhaps the same one. Stuntingof the plants was observed in residual peanutcrops for 2 years.

W. V. CampbellI was surprised that so few insects werementioned as pests in the country reports,except as vectors of virus diseases such asrosette. Are insects not a serious problem or isit because there is a lack of detailed investiga-tions on crop losses or entomologists workingin these countries?

S. M. MisariI think that entomological aspects have been

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neglected. Very often people look only for thedramatic effects, e.g., a heavy infestation ofaphids that are easy to see. If you look care-fully, the groundnut plant contains a richfauna. Over 70 insects have been reported tocause damage to groundnuts in Nigeria; apartfrom the noninsects such as termites andmillipedes, which are also important pests.

C. HarknessWe got an unexplained increase in yield in the1979 season from insecticide-treated plots inNigeria. Treated plots gave 2600 kg/ha com-pared to 1800 kg/ha from untreated plots. Wedid not determine which pest or pests wereinvolved.

A. S. PompeuThere are many reports of insect pests ongroundnuts in Brazil but very few reports onthe actual losses due to pest attack. The majorpest in Brazil is Enneothrips flavens, which canreduce yields from 10to 100% with an averageof 30%.

Vikram SinghAphids can cause 40% yield losses in India andthe red hairy caterpillar from 35 to 40% yieldloss.

K. MiddletonGenerally, in Australia there are not seriouspest problems. Controlling mites and jassidsgives a cosmetic improvement in appearanceof the crop rather than a yield improvement.Large losses have been caused by whitegrubsbut no effective soil insecticide has yet beenapproved by the authorities. Heliothis cancause up to 35% defoliation without affectingyields.

P. W. AminInsect pests are important in West Africa andso are millipedes and termites in Nigeria,Sudan, Upper Volta, and Senegal. Many far-mers use insecticides in the Sudan. Storagepests are also important, and they causequality losses as well as destroying seeds. Mysecond comment is that the entomologiststhemselves have not done enough on quanti-fying losses, particularly in financial terms.The first priority must be to obtain moreaccurate figures.

D. R. C. BakhetiaCarbofuran 3G at 1 kg a.i./ha and carbofuran50% WP at 2.5 g a.i./kg seed have been foundto be very effective against white grubs inIndia. Yield increases of between 53 and 144%have been recorded by controlling whitegrubs.

A. B. SinghYield losses due to white grubs and termitesvary from season to season and dependupon the soil type and the moisture level.Losses due to white grub may reach 80%.

D. H. SmithWhat about the importance of nematodes,which have not been mentioned?

S. M. MisariA seed coat inhabiting nematode has beenrecorded in Nigeria. Approximately 11 speciesof nematode have been reported fromgroundnuts. Much more work is needed in thisarea.

R. O. HammonsSeed lots from Nigeria kept in a cold store atthe germplasm center in Georgia were foundto be infested with the seed coat nematodementioned by Dr. Misari. This poses a quaran-tine problem.

P. GillierWe get yield increases from applying carbo-furan to the soil in Senegal, but so far it has notbeen determined whether these increases aredue to the control of nematodes or other soilinhabitants.

J. GautreauIn 1975, nemagon-treated plots in Senegalgave yield increases of 39%, and there wasalso a significant residual effect. Nemagontreatment is difficult and expensive for small-scale farmers.

R. O. HammonsFive hundred germplasm lines were screenedunder controlled conditions in Georgia forresistance to the root knot nematode, but noresistance was found.

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Session 9

Plenary Sessionand General Discussion

Chairman: R. W Gibbons Rapporteurs: D. McDonaldJ. P. MossD. V. R. RoddyJ. H. Wil l iams

Plenary Session

The Chairman opened this session with theremark that it should be kept as informal aspossible and although there were some specificpoints to be covered, any point could be raisedin the general discussion.

The first item on the agenda was the reportsfrom the Chairmen of the sessions, in whichthey briefly summarized the papers and discus-sions presented during the respective sessions.Following these reports, there was a generaldiscussion of the major points brought outduring the Workshop.

Summary of Session 2 Research Organizat ionand Development

C. Harkness — Chairman

Delegates have been presented with a goodpicture of groundnut research organization anddevelopment in both developed and develop-ing agricultural systems. Dr. Vikram Singh hasprovided a comprehensive report on the ac-tivities of the All India Co-ordinated ResearchProgram for Groundnuts, a large and complexorganization. The large numbers of scientistsand institutions concerned with research ongroundnut problems in India make an organi-zation such as AICORPO a necessity if costlyduplication of effort is to be avoided. Dr. Gilliergave an excellent description of the role of IHROin groundnut research and development withparticular reference to West Africa. His com-ments on seed multiplication are highly rele-vant and of great value to workers in develop-ing countries. Dr. Hammons talked aboutgroundnut production in Georgia. He describedthe advances and improvements in farmmachinery, weed control, crop protection,supplementary irrigation, and breeding whichhave together resulted in a high and stableproduction of groundnuts in Georgia. Dr.Hammons stressed the important part played inthis success story by the extension services.There is a great need to improve extensionservices in developing countries as many usefulfindings are not getting through to the farmer.

Dr. Jackson's explanation of the Title XIIproject for cooperative research on groundnutsbetween USA institutions and research organi-zations in the developing countries was particu-larly well received by delegates. The benefits tobe obtained by such linkages should be evidentto all who have attended the present workshop.

Summary of Session 3 Genetics and Breeding

ft. O. Hammons — Chairman

In the initial paper of this session, Dr. V. R. Raostressed the need for collecting and conservingthe world's groundnut genetic resources beforefurther genetic diversity is lost and as cropimprovement replaces ancient landraces. De-velopmental activities will soon result in theirretrievable loss of valuable genes. He tracedthe scope and present status of ICRISAT's dualefforts in the collection, maintenance, andevaluation of such germplasm and itsdocumentation and distribution. There havebeen substantial inputs to the germplasm bankfrom many countries as well as requests fordissemination. Each Workshop participantshould have gained the perspective of thespecial obligation that a groundnut scientistshould have to insure that the material alreadyassembled in a particular country should bemade available to ICRISAT and to secondarycenters.

In discussing documentation. Dr. Rao re-ported that a descriptive language is underpreparation by which evaluations can be com-puterized to facilitate information retrieval fromthe catalog. Finally, he pointed to the quaran-tine constraints that are necessary to minimizethe possibility of introducing a new and destruc-tive pest or pathogen into a country during seedtransfer.

For improvement of the crop one starts with a portion of the available genetic variation and,through one of the basic techniques used in

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self-pollinated species, breeds for yield stabilityby one or more of the procedures outlined byDr. A. J. Norden. Here considerable interest wasshown in the multiline variety concept that hasbeen successfully employed in Florida, USA, tomaintain greater genetic diversity in new cul-tivars than that in the pure lines they replaced.

This report described the successful cooper-ation among U.S. breeders and the multidiscipli-nary team effort involved in research and de-velopment and introduction of new varietiesinto agricultural production and use by theconsumer.

From a breeding program that has been incontinuous progress since 1928 in Florida, ourattention was directed by Dr. S. N. Nigam andco-workers to the 4-year-old program atICRISAT. Here the emphasis is not toward thedevelopment and release of the finished varietybut, rather, the emphasis has been and iscontinuing on producing and disseminatingsuitable breeding material to cooperators indifferent countries of the SAT. Under the condi-tions at ICRISAT Center, exceptional numbersof cross-pollinations have been achieved, andvery large populations of bulked breeding linesare evaluated in appropriate field designs toprovide promising selections for distribution inareas that address many of the major con-straints presently limiting production in theSAT.

Summary of Session 4 Cytogenet ics and Ut i l izat ion ofWi ld Species

V. S. Raman — Chairman

The two papers presented in this sessionevoked considerable discussion. The majoremphasis has been on the analysis and use ofwild species that are currently available, andthis should be continued and expanded inscope to include newly collected material. Theapplication of D2 analysis to chromosome armratios to increase the knowledge of relation-ships between wild species to facilitate theirutilization is of interest. Aneuploids have re-

ceived little attention in the past, buttheseare ofimportance and more emphasis is needed,especially on their breeding behavior, becauseour knowledge of aneuploids in Arachis ismeager compared with the great advances thathave been made in some other crop plants, forexample Triticum and Nicotiana.

The absence of reports on haploids in A hypogaea either from twin seedlings or pro-duced by anther culture was noted. Thesewould also be useful in isolating aneuploids.

Another constraint on the utilization of wildspecies, especially on the production of am-phiploids and synthesis of A hypogaea from itswild ancestors, is that there is only one specieswith the B genome, and this limited the range ofdifferent amphiploids that could be produced.However, the production of hybrids and hexa-ploids, their screening for potentially usefulcharacters, especially disease resistance andyield potential, should receive high priority.

The increased knowledge, with the improvedtechniques and the wider range of germplasmnow available, is leading to greater possibilitiesin the utilization of wild species of Arachis.

Summary of Session 5 Crop Nut r i t ionand Agronomy

A. Narayanan — Chairman

The environmental factors responsible for ef-fective nodulation in relation to crop growthneed extensive investigations in order to im-prove the nitrogen nutrition of groundnuts. Theinfluence of fertilizer nitrogen with reference tonodule formation in the seedl ing stage was alsostressed. To determine the requirement of nitro-gen, a proper balance sheet has to be workedout for various soil types and populargenotypes. It will aid in arriving at an appropri-ate crop rotation. The utilization of biologicallyfixed nitrogen by a subsequent crop, especiallya cereal in a rotation, is an important area to beconsidered.

Rhizobial strains are specific for genotype

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and location, thereby indicating no possibilityof having a universally efficient strain forgroundnut.

The isogenic nonnodulating lines can be usedfor quantifying the nitrogen fixed by nodulesand the uptake from the soil. It is known thatnonnodulating character is genetically control-led, probably by two genes. Evidence is alsoavailable to show that genotypes differ in theirability to fix nitrogen.

The mode of inoculation is an important basisfor better nodulation. The seed and/or soiltreatment(s) with fungicides, pesticides, or her-bicides may influence the nodulation and fix-ation of nitrogen. Application of rhizobial in-oculum below the seed, either in the liquid formor with sand, may help to avoid the harmfuleffects of fungicides used for seed treatment.

Since the soils of the SAT areas are poor inphosphorus the exploitation of mycorrhizalfungi was also stressed.

High partitioning and longer pod fillingperiod are the two important bases for yieldimprovement under optimum growing condi-tions. These two criteria, in addition to seedlingvigor and rapid canopy development etc., maybe used for breeding better genotypes for yield.However, in the SAT regions, the haulms ofgroundnut are used as cattle feed; thus itbecomes an economic yield. Therefore, thephysiological bases stressed above may not beapplicable for such conditions.

Groundnut is intercropped with various cropsincluding cereals in various parts of the world.This system has proved to be physiologicallyefficient and economically feasible. Informationon the pattern of disease spread in this systemis to be gathered for making the system stillmore efficient.

Summary of Session 6 Groundnut Entomology

W. Reed — Chairman

The Chairman opened the session with the

observation that entomology of groundnutshas always been an underrated input. Insectpests causefar greater losses to this crop than isgenerally realized. The cost of the insecticidespoured onto this crop worldwide far exceedsthat of the fungicides. In this workshop theentomology session had been allocated onehour, only two papers were presented, andthere were relatively few entomologists in thegathering.

The first presentation was by Dr. Campbell,entomologist, and Dr. Wynne, plant breeder,both from North Carolina State University. Theydescribed their work on resistance ofgroundnuts to insects and mites. The resultsreported were impressive, with substantial re-sistance to all of the major insect pests of theirarea having been discovered and subsequentlyutilized in commercial introductions. Resis-tance to thrips, leaf hopper, Heliothis, andDiabotrica was described and illustrated. Inaddition substantial resistance to the two-spotted mite was reported; this mite being aninduced pest following the use of insecticidesearly in the season. The current work is aimed atincreasing the levels of the resistance andcombining these with resistance to diseases,which has been developed by pathologists.

Dr. Amin and Dr. Mohammad, entomologistsof ICRISAT reported on the current status oftheir groundnut pest research. Here the initialemphasis has been on the major pests on theICRISAT farm, i.e., thrips and jassids, with theprimary aim of reducing the damage in theresearch fields and so facilitating the researchof the groundnut scientists. The work wasstructured under three main headings, (1) sur-vey of the pest problems, (2) ecology andbiology of the major pests, and (3) screeninggermplasm for resistance.

Although this program began less than 3 years ago substantial progress was reported. Inparticular the work on Frankliniella schultzei, which is now known to be the major vector ofthe bud necrosis disease, has already given us a means of reducing this problem in our fields,with early sowing, close planting, and preciselytimed insecticide use all contributing to a majorreduction of thedisease incidence. Initial resultsfrom screening the available germplasmagainst thrips, jassids, aphids, and termites lookpromising.

There was limited time for questions and

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discussion, but it was evident that the represen-tatives from India regard white grubs as themajor pest problem. These pests are devastat-ing large areas and are displacing this particu-larly susceptible crop from several districts.Major questions asked were whether ICRISATcould take up research on these pests and wasthere any hope of host plant resistance being ofany utility against such polyphagous pests.

It was pointed out that white grubs are notcommon at ICRISAT Center and the initial re-search has been concentrated upon the locallydamaging pests. In future, increased resourcesmay become available and at that time duepriority will be given to supplementing thenational efforts against this pest, if a suitablesite in an endemic white grub area can be madeavailable. The successes reported in locatingresistance to Heliothis, which is also a polyphagous pest, should encourage us in thesearch for white grub resistance. Another ques-tioner brought the attention of the meeting tothe importance of aphids as pests and vectors ofrosette in Africa.

The Chairman had to cut short the discus-sions because the allocated time had beenexceeded. He congratulated the speakers anddiscussants on their clear and precise contribu-tions. The time limit ensured that the quantitywas limited but this was compensated for byhigh quality. The report by Dr. Campbell, whohad dedicated over 20 years to this work,exemplified the need for persistence in hostplant resistance research because worthwhileresults will only come with continuity. Far toomany programs are initiated and then changedor dropped after two or three seasons. TheICRISAT program had made a good, enthusias-tic beginning, and it is hoped that an expandingpest management research effort, aimed atpractical improvements at the small farmerlevel, will be built on these firm foundations.There was a clear advantage in cooperation andcommunication between research programsboth nationally and internationally. ICRISATcould derive enormous benefit from the well-established programs at North Carolina andelsewhere. The thrips, jassids, and Heliothis methodology and materials developed by Dr.Campbell will be of obvious value to the prog-ram being developed at ICRISAT, and it isessential that maximum advantage should bederived. We should not reinvent the wheel in

each and every research program.There is a clear need for an expansion in

resources devoted to groundnut entomologyresearch. This need has been recognized, andICRISAT will be expanding its staffing andresources in this area in the near future.

Summary of Session 7 Groundnut Pathology

J. S. Chohan — Chairman

It was strongly felt that diseases (fungal andviral) are causing the greatest constraints togroundnut production in the SAT. The re-searches to date appear to be inadequate indepth regarding the biology, agroecology of thehost-pathogen systems and host resistance. Inspite of the good work conducted by someinstitutions/countries in the SAT and particu-larly at ICRISAT Center, a lot more needs to bedone, particularly with respect to screening ofgermplasm and distribution of the resistantlines to countries in the SAT.

Keeping this in view, although some goodgermplasm screening methods (epidemiologi-cal) have been perfected for some pathogens,more efforts are needed in this direction in theremaining economically important pathogens,especially the soilborne ones and the viruses.Concomitantly, additional laboratory equip-ment, screen houses, and other associatedfacilities are required.

After intensification, all these inputs shouldlead to a major emphasis and breakthrough onthe development of stable disease resistance inthe not too distant future. It was envisaged thatlooking at the meager resources at the com-mand of the SAT farmers, regional programsshould now be strengthened to achieve theabove objectives. Close cooperation with scien-tists in other disciplines is of paramount impor-tance to develop effective techniques in host-pathogen-environment system(s), and thisshould be continued.

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Summary of Session 8 Country Reports

A. W. Gibbons and J. P. Moss Co-Chalrman

The Chairman opened the session with theobservation that this was probably the mostimportant day of the Workshop because thedelegates would be hearing about groundnutproduction, utilization, research problems, andfurther research needs from 17 countries repre-senting widely different geographical areas,with widely different production methods.These methods ranged from completelymechanized systems to production methodsrelying almost entirely on hand labor, usingsimple tools or, at the most, bullock-drawnequipment. The Chairman also remarked thatthis session was particularly important to theICRISAT Groundnut Program scientists as theyare now at the stage where genetic materialsare becoming available for dissemination toother countries, particularly those in the SAT. Itwas important that the ICRISAT research goalswere matching the needs of client countries.

The first session of the day was devoted toAustralia and Asia. The Australian groundnutsituation was rather unique in that although theproduction system was highly mechanizedthere were still serious deficiencies, particularlyin the supply of good quality planting seedOnly one rainfed crop is grown in a year anddrought is a common problem. At present theavailable planting seed was drawn from theindustry and it was often contaminated with A.flavus. Aflatoxin is, in fact, a very serious prob-lem and is receiving a lot of attention. Incontrast, the Southeast Asian countries ofBurma, Malaysia, and Thailand are often able togrow two crops of groundnuts in a season. InMalaysia, groundnuts are often grown underplantation crops. Both Burma and Malaysiahave relatively young research programs. InThailand, the research infrastructure is moreadvanced and plans have been implemented toincrease production over the next 5 years. Ingeneral the disease and pest situation in South-

east Asia does not appear to be as serious as it isin India, although the common diseases such asrust and leaf spots are always present. Thedevelopment of suitable cultivars to fit into thegroundnut farming systems, the need formechanization, and the strengthening of re-search inputs are important in this region.

The second group of papers covered the maingroundnut producing countries of SouthAmerica — Venezuela, Argentina, and Brazil.The production systems in Venezuela andArgentina are highly mechanized in contrast toBrazil where the production is mainly by smallscale farmers. In Brazil, two crops of earlymaturing groundnuts can be taken in a season.However, there has been a serious decline ingroundnut production in Brazil due to competi-tion from soybean. Leaf spots are prevalentthroughout the region, but rust is only a threat inVenezuela. In Brazil, the main pest is a species ofthrips. Valuable germplasm collections ofSouth American landraces are maintained atManfredi in Argentina, and wild species aremaintained in Sao Paulo, Brazil.

The reports from Africa showed a wide rangeof variability in production methods, researchinputs, and problems. In many West Africancountries there has been a serious decline inproduction, mainly due to the succession ofdroughts, particularly in the Sahelian zone.Nigeria and Senegal have had a long history ofsuccessful and continuing research programs.Particularly noteworthy has been the breedingof rosette-resistant cultivars in Senegal, andlater in Nigeria, and the breeding of cultivarswith drought resistance in Senegal. Thetransferof technology from research findings to im-plementation by the farmer, however, remainsa problem in many of the African countries.The situation in Sudan, one of the leadinggroundnut producing countries, is in contrastto that of many of the other countries inAfrica as the bulk of the crop is grown underirrigation in the Vertisols of the Wad Medanischeme and yields average about 1440 kg/ha.These irrigated areas are mainly for the produc-tion of large-seeded confectionery nuts for ex-port. In the rainfed areas, early maturing cul-tivars are grown and average yields are around600 kg/ha. Harvesting, however, is a problem onthe heavy Vertisols.Only recently has a fulltimeplant breeder been appointed.The reports from eastern and central Africa

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also showed some striking contrasts. Malawiand Zimbabwe have a long history of successfulplant breeding and disease control programs.Malawi produces a high quality confectioneryexport crop as well as cultivars for oil crushingto satisfy the internal demands for vegetablecooking oils. Zimbabwe has high input produc-tion areas, which receive supplementary irriga-tion, and low input rainfed areas. Most of thecrop is used for local consumption. BothMozambique and Tanzania wish to increasegroundnut production but suffer from a lack ofconsistent research programs and germplasm.These countries have recently initiated breed-ing and agronomic research programs, but itwill be some time before results are obtained.

In general, the disease and pest situation inAfrica is serious. Leaf spots and Aspergillus flavus are major pathogens and rosette virusstill presents serious problems although, resis-tant cultivars are available from both West andcentral Africa. Rust is now present in almost allof the major groundnut growing areas but is notserious at present, probably because only onecrop a year is usually grown, and the long dryseasons prevent a continuous inoculum beingpresent. Pests are important — particularlyaphids, white grubs, millipedes and thrips.Drought is a major recurring problem and theneed for more research effort in this area isimportant. The yield gap between the potentialyields and those actually obtained by the farmerwas reported from many countries.

In conclusion the Chairman thanked all thespeakers for their excellent presentations and m particular for keeping to the time allotted. Thepapers stimulated a great deal of useful discus-sion which was of immense value to theICRISAT program.

General Discussion

ChairmanThe Director General, Dr. L. D. Swindale,charged the delegates in his opening addresswith the task of evaluating and criticizing theICRISAT Groundnut Improvement Programand to make suggestions on how it could beimproved. We would be pleased to have theviews and suggestions of the delegates.

J. S. ChohanI would suggest that the regional programsshould be strengthened and that more em-phasis should be put on training.

ChairmanThe regional aspects of the Groundnut Im-provement Program are being strengthened.In 1981, an outreach program will be startedon a regional basis in Central and EasternAfrica, and a similar program is due to com-mence in West Africa in 1982. Besides this, weare strengthening regional work in India andother countries through the national prog-rams. In India, we are conducting research atstations that have been mutually agreed uponby the Indian Council of Agricultural Research(ICAR) and ICRISAT. We are also increasingour training through the Institute's trainingprogram and by giving specialist short-termtraining through our own program. Our staffgive lectures to the trainees, and this yearseveral in-service trainees from Africa andAsia are specializing on groundnut researchprojects. Besides this, we have research schol-ars working on M.Sc. theses at ICRISAT. Theydo their course work at the Andhra PradeshAgricultural University and their research atICRISAT. These scholars come from India,Ghana, and Benin. We expect to increase ourtraining activities in the very near future.

J. M. TeriHas ICRISAT come up with the best methodsof advising national programs? I have in minda system whereby ICRISAT scientists canmake extended visits, lasting for 2 weeks orlonger, to work in situ with groundnut resear-chers in the SAT countries. This would be asequally important as the researchers comingto ICRISAT.

ChairmanThis is exactly what does happen with ICRISATresearch scientists, particularly in the well-established programs. The Groundnut Im-provement Program has been in a process ofbuilding up its center activities, and staff werestill being recruited in 1978 and 1979. We havealready made trips to S. America, Africa, Asia,and Australia. These trips will become morefrequent and, once the African program hasstarted, we will have ICRISAT scientists actu-

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ally based in Africa and working on a regionalbasis. They will visit the national programs intheir region as often as possible.

T. P. YadavaI think that as drought resistance is one of themost important problems in the SAT, thisshould be extensively worked on at ICRISAT.The economic aspects of groundnut produc-tion, particularly in the field of pesticide use,should also be closely studied.

ChairmanDrought resistance will become a major partof the ICRISAT physiology research program.The physiologist only joined just before theworkshop and is now recruiting more staff. A great deal of work has been done in this area inSenegal also, and we hope that strong co-operation can be developed between theirprogram and ours.

Similarly the economists at ICRISAT are nowgoing to look at the various economic aspectsof groundnut production.

K. S. LabanaI would like to suggest that information relat-ing to the release of cultivars, new agronomicpractices, and many aspects of groundnutresearch should be released through an inter-national newsletter.

ChairmanThis is in fact being considered by the ICRISATgroundnut program. International newslettersare already being circulated from the cereal andpulse programs. At the moment, the groundnutresearch community is well served by 'PeanutResearch', which is produced by APRES andwith which Dr. Hammons is closely as-sociated. Perhaps he may care to comment?

R. 0. HammonsThe APRES newsletter 'Peanut Research'could be reproduced and circulated globallyby ICRISAT. However, the world community ofgroundnut scientists would welcome and en-courage the initiation by ICRISAT of an 'Inter-national Groundnut Newsletter'.

ChairmanWe will certainly give this very serious con-sideration.

D. H. SmithThere is a need for a global informationretrieval system for groudnuts including a translation service and reprint service.

ChairmanThis is also being considered. There is aninformation system for sorghum and millets atICRISAT which is being financially supportedby the International Development ResearchCenter (IDRC). It is called 'SMIC (Sorghum andMillet Information Center). It would certainlybe desirable to have such a system at ICRISAT,but this has been also discussed by otherorganizations.

R. 0. HammonsI agree; various international organizationshave discussed the need for a computer-basedinformation center for groundnuts. Hopefully,such a system can be worked out.

P. GillierIn the case of foreign publications, IHRO can,within the limit of their capabilities, furnish allthe information from their documentation sys-tem.

ChairmanPerhaps Title XII could consider such a requestfor financing or operating such an inter-national information system?

C. R. JacksonIt could be a possibility, and also I would like tosuggest that there should be internationalmeetings of groundnut workers at regularintervals.

J. S. ChohanAs an extension of the idea of publications tobe prepared by ICRISAT, it would be valuableto prepare annotated bibliographies, for ex-ample, on diseases of groundnut. Preferablythese could be prepared for individual dis-eases when they are of major importance. Ifscientists had this sort of information theywould be better informed and would be moreeffective in workshops such as this one.

V. RagunathanI agree. Several such handbooks have beenproduced by the sorghum and millet prog-

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rams and also by the chickpea program atICRISAT.

ChairmanWe realize the importance of bibliographiesand handbooks, particularly those which willbe of value to field workers. A start has beenmade on this already. Two handbooks onaflatoxin procedures have been prepared and,in conjunction with Dr. Hammons, a rustmonograph is being prepared that will containan annotated bibliography.

R. 0. HammonsIs sufficient work being done on improvingpreharvest technology? This subject wasbarely touched upon in this workshop. Thereappears to be a pressing need for improvingthe 'desi' plow, the lifting plow, and the smalldecorticator. If the work has been done, is theinformation being disseminated?

ChairmanThe Farm Machinery Unit of the FarmingSystems Research Program at ICRISAT is cur-rently working on the improvement of equip-ment for the small farmer. This work willinclude equipment for groundnuts. A greatdeal of work has also been done to my know-ledge in Senegal, Nigeria, Malawi, Botswana,and in India. This information should begathered together, if it has not already been,and then disseminated.

C. HarknessCan ICRISATdo more in thefield of agronomicand herbicide research?

ChairmanA certain amount of herbicide work has beendone, again by the Farming Systems ResearchProgram, at ICRISAT. However, at the outset ofthe program the consultants who outlined thegroundnut program for ICRISAT stressed thatmuch of the agronomic research needed ongroundnuts is very locale specific, and shouldbe done by the national programs. Agronomicwork is very much related to local soils andenvironments. When we commence our out-reach programs we will be more closely as-sociated with this type of research.

K. S. LabanaWhat are the possibilities of ICRISAT conduct-ing international variety trials? The best var-ieties from each country could be included andthis would give us information on their per-formance over a wide range of environments.

ChairmanThe idea is a good one and has been discussedbefore. One major problem has been thequarantine regulations of some countries.These problems include the import restric-tions based on importing seed from certaincountries because of the disease situation inthe exporting countries. Many countries onlyallow limited seed to be imported and otherswill only release material that has been grownfrom seed to seed. All these restrictions makeit difficult to conduct global trials. We do havemost of the necessary material in ourgermplasm collection and this would have tobe multiplied first in the recipient country.Perhaps Dr. McCloud would care to commentbecause he tried to conduct international trialsafter the 1975 meeting held in Florida.

D. E. McCloudThe International Peanut Program at the Uni-versity of Florida collected about 33 of theworld's outstanding cultivars. These weremultiplied in Florida for distribution but fundswere not adequate or forthcoming to com-plete this project.

R. 0. HammonsThe international variety trials concept hasbeen considered again by a panel of scientistsduring the past year. Under present quaran-tine constraints it is difficult but the questionshould remain on future agendas.

As mentioned, one of the problems is thelimited amount of seed which can be importedby some countries. This means that with somevarieties, which are in fact multilines, it wouldbe difficult to maintain their genetic integrity ifonly 5 to 10 seeds were allowed to be im-ported. For example, Florigiant is compositedfrom 8 components and 5 to 10 seeds of thiscultivar would not be sufficient.

ChairmanWe have circulated a questionnaire preparedby the ICRISAT groundnut scientists which

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would provide a great deal of informationwhich would be useful for compiling informa-tion on most aspects of groundnut production.We would like delegates to consider this ques-tionnaire at length when they return home andmake suggestions on how it could be im-proved. If anyone has had time to read it, wewould invite comments now.

J. S. SainiUnder the section on soils I suggest that thenutrient status of the soil may also be includedso that it can be correlated with fertilizer re-sponse. Rainfall figures should also be givenon a monthly basis rather than a seasonal onewith the average number of rainy days per

month. Average monthly temperaturesand relative humidity should also be included.

The Chairman concluded the session bythanking all the people who had helped toorganize the workshop and, in particular, theparticipants who had presented papers and hadtaken part in the discussions. Professor C. Hark-ness, Ahmadu Bello University, Nigeria, onbehalf of the delegates thanked the DirectorGeneral of ICRISAT and his staff for invitingthem to ICRISAT and giving them the opportun-ity to take part in the Workshop.

311

Appendix 1

Poster Session

Pos te r Sess ion

The following papers appeared in poster sessions or were distributed during the Workshop. Copiescan be obtained from the authors.

Groundnut Breeding: Some Considerations

R. Pankaja Reddy and N. G. P. Rao*

National Research Centre, IARI Regional StationRajendranagar, Hyderabad 500 030, India

(•Present address- ICRISAT, PMB 1044, IAR, ABU, Samaru, Nigeria).

Abstract

Early maturing bunch type groundnuts have largely been replaced by runner types in many parts of the USA. This subspecific shift has not taken place in India or Africa. Under uncertain rainfall situations in India runners are grown but under the more assured conditions of irrigation bunch forms are grown, which is the reverse of the USA system. The question of whether the subspecific status of rainy and postrainy crops in India should be changed needs investigation. The modern cultivars in the USA are more efficient in partitioning photosynthates to the pods but this does not appear to be happening with Indian cultivars and priority should be given to this by breeders. Through the choice of suitable parents it should prove possible to generate material which is suited to both rainy and postrainy seasons in India. Groundnut also offers scope for fitting into profitable and stable intercropping, relay cropping and sequential cropping systems. This again should be a priority research area.

G r o u n d n u t Research a t P u n j a b A g r i c u l t u r a l U n i v e r s i t y

Oilseeds Section, Department of Plant BreedingPunjab Agricultural University

Ludhiana, Punjab 141 004, India

Abstract

Groundnut production has increased rapidly since the crop was first introduced in 1931. Presently the crop occupies 0.13 million hectares with an average yield of about 886 kg lha. About 82% of the crop is grown under rainfed conditions, and groundnuts are rotated with irrigated wheat. Five groundnut cultivars have been released since breeding commenced, and one of these cultivars, M-13, has been released on a national basis. The cultivar M-13, however, is too late in maturity for Punjab conditions, and it has been replaced by new cultivars. The latest cultivar, M-37, was released in 1980, specifically for rainfed conditions. A new package of agronomic practices has been evolved which has substantially increased yields. White grubs, aphids, leaf webbers, termites, and hairy caterpillars are serious insect pests. Considerable research has been conducted on the biology and control of these pests, both by chemicals and by identifying sources of resistance. Of the diseases, collar rot and leaf spots are important and control measures have been recommended.

315

Clump' virus is a relatively new disease and is causing concern. It appears to be soilborne, and methods of control are being investigated.

Product ion Problems in Groundnut — Impact of Improved TechnologyRelating Mainly to Conditions in the Punjab, India

J. S. Saini

Agronomist (Oilseeds), Punjab Agricultural University, Ludhiana, Punjab 141 004, India

Abstract

On the research farm the approved package of practices increased the pod yield by 133%, shelling by 7.5%, total oil yield by 169%, and the haulm yield by 134% over the farmers' local practices. The most important among the production factors were protective irrigation, weed control, harvesting at full maturity and fertilizer application. Omission of these factors from the package of practices reduced the mean pod yield by 33%, 32%, 26%, and 20%, respectively. Control of leaf spots was only important during a high rainfall season. When some of the more important practices were tested in unrep/icated large plots (0.4 ha) on farmers' fields they gave on an average yields of 1730 kglha compared to 1170 kglha obtained from the local methods. This represented a yield increase of 48%. Future research strategies are also discussed to further enhance yields.

Induced Mutants in Peanut (Arachis hypogaea)

M. V. R. Prasad and Swamalata Kaul

IARI Regional Station, Rajendranagar,Hyderabad 500 030, Andhra Pradesh, India.

Abstract

It was envisaged that the use of mutagens was a possible method whereby increased pod production could be achieved with a reduction in plant canopy structure. Seeds of standard Spanish and Virginia cultivars were subjected to a wide range of mutagens such as gamma rays, EMS, and NMU in different doses. In the Spanish cultivars, mutants characterized by a compact canopy frame and short intemodes invariably produced fewer pods. Mutants with a large number of pods did not have compact canopies. A Virginia runner mutant with narrow leaves was developed however from a Spanish cultivar. In addition to the narrow leaf character, there was an increased number of nodules in the deeper areas of the root zone, a reduced susceptibility to leaf spots, an increase in pod number and the seeds were non-dormant. In Virginia types it was possible to develop mutants combining a compact canopy and more pods, as well as high yielding plants without any compaction of the canopy. The useful mutants are being utilized in recombination breeding prog-rams.

316

The Di f ferent ia t ion and Ident i f icat ion of the Chromosomesand the Embryology of Arachis with Reference

to Alien Incorporation in Groundnut

U. R. Mur ty , P. B. K i r t i , M. B harati and N. G. P. Rao

IARI Regional StationRajendranagar, Hyderabad 500 030 (A.P.)

Abstract

Triploid interspecific hybrids were produced between 10 varieties of Arachis hypogaea L and a wild diploid species, A. chacoense (PI 276235). The hybrids exhibited varying chiasma frequencies, indicated differences in the pairing ability of the chromosomes in the different groundnut varieties and suggested possibilities of increasing the success of alien incorporation. To enable general cytogenetic studies, and particularly to identify alien addition and substitution races, the twenty pachytene chromosomes of groundnut were identified, described and classified for the first time. The 'A' chromosome was found to correspond to a small chromosome that was completely heterochromatic.

To fill the gap in our knowledge of seed failure in some Arachis species, the embryology of a rhizomatous species was studied. Fertilization proceeded slowly and incompletely and seed failure was brought about by a cessation in the endosperm development and by a hyperplastic development of the endothelium. Triploid interspecific hybrids exhibited embryological features suggestive of non-recurrent apomixis.

317

Appendix II

Participants

Part ic ipants

Argent ina

J. R. PietrarelliINTA, Manfredi Research Station, 5988Manfredi

Austral ia

K. J. MiddletonDepartment of Primary IndustriesBjelke-Petersen Research StationKingaroy, Queensland

Brazil

A. S. PompeuInstituto Agronomico, CP2813100 Campinas, S.P.

Burma

U. Win NaingAgriculture CorporationMagwe DivisionMagwe

France

P. GillierAnnual Oilcrops DepartmentIHRO, 11 Square Petrarque7501L, Paris

Ethiopia

A. KrauszP.O. Box 30726Plant Genetic ResourcesWest German EmbassyAddis Ababa

India

V. ArunachalamNational FellowIndian Agricultural Research InstituteRegional StationRajendranagarHyderabad 500 030

D. R. C. BakhetiaEntomologist (Oilseeds)Punjab Agricultural UniversityLudhlana 141 004Punjab

A. S. ChahalPlant Pathologist (Oilseeds)Punjab Agricultural UniversityLudhiana 141 004 Punjab

J. S. ChohanJoint DirectorPlant Disease ClinicCommunication CenterPunjab Agricultural UniversityLudhiana 141 004Punjab

N. D. DesaiResearch Scientist (Oilseeds)Gujarat Agricultural UniversityJunagadh 362 001Gujarat

M. P. GhewandeScientist (Plant Pathology)Directorate of Oilseeds ResearchRajendranagarHyderabad 500 030

B. S. GillNational FellowGujarat Agricultural UniversityJunagadh 362 001Gujarat

S. V. JaiswalGroundnut BreederPunjab Agricultural UniversityLudhiana 141 004Punjab

N. C. JoshiDirectorCPPTIRajendranagarHyderabad 500 030

K. S. LabanaSenior Oilseeds BreederPunjab Agricultural UniversityLudhiana 141 004Punjab

D. P. MisraDirectorNational Research Centre for Groundnut (ICAR)Opp. TimbawadiJunagadh 362 002

321

V. V. ModhaChief AgronomistThe Vanaspati Manufacturers' Association of India6th Floor, Harilela House28/32 Mint RoadBombay 400 001

U. R. MurtyNational FellowAll India Coordinated Sorghum Improvement ProjectIARI StationRajendranagarHyderabad 500 030

A. NarayananProfessor of Crop PhysiologyAndhra Pradesh Agricultural UniversityRajendranagarHyderabad 500 030

G. D. PatflOilseeds SpecialistMPKVJalgaon 425001Maharashtra

S. H. PatilBhabha Atomic Research CentreBiology & Agriculture DivisionBombay 400 085

M. V. R. PrasadGeneticistIndian Agricultural Research InstituteRegional StationRajendranagarHyderabad 500 030

V. RagunathanDeputy DirectorCPPTIRajendranagarHyderabad 500 030

N. RajagopalAssistant Oilseeds SpecialistReg tonal Oilseeds Research StationKadirl515 501Anantapur District, A.P.

V. S. RamanProfessor & Cytogenetlcist (Oilseeds)Tamil Nadu Agricultural UniversityCoimbatore 641 003

V. RavindranathPlant PathologistIARI Regional StationRajendranagarHyderabad 500 030

C. Raja ReddySenior Scientist, Groundnut BreedingNational Agricultural Research ProjectS.V. Agricultural CollegeTirupati 2

M. S. S. ReddyOilseeds SpecialistAndhra Pradesh Agricultural UniversityAgricultural Research InstituteRajendranagarHyderabad 500 030

M. V. ReddiHead, Department of Plant BreedingCottege of AgricultureBapatla

P. S. ReddyProject Coordinator (Groundnut)Punjabrao Krishi VidyapeethAkola 444 104Maharashtra

R. Pankaja ReddyGroundnut GeneticistAll India Coordinated Sorghum Improvement ProjectRajendranagarHyderabad

J. S. SainiAgronomist (Oilseeds)Department of Plant BreedingPunjab Agricultural UniversityLudhiana 141 004 Punjab

I. S. SekhonDepartment of Plant BreedingPunjab Agricultural UniversityLudhiana 141 004Punjab

A. B. SinghBreeder (Groundnut)Groundnut Research StationMainpuri 206001Uttar Pradesh

322

Vikram SinghProject DirectorDirectorate of Oilseeds ResearchRajendranagarHyderabad 500 030

S. ThangaveluBreeder (Oilseeds)Cashew Research StationVriddhachalam 606 001South Arcot DistrictTamil Nadu

T. P. YadavaProject LeaderDepartment of Plant BreedingMaryana Agricultural UniversityHissarHaryana 125 004

Malawi

C. T. KisyombeMinistry of Agriculture & Natural ResourcesChitedze A.R.S.P.O. Box 158, Lilongwe

D. E. McCloudInternational ProgramsUniversity of FloridaChitedze A.R.S.P.O. Box 158, Lilongwe

P. K. SibaleMinistry of Agriculture & Natural ResourcesChitedze A.R.S.P.O. Box 158, Lilongwe

Malaysia

H. B. HamatField Crop Research StationLot 206/94 Sect. 20 Jalan Raja Dewa HuluKota Bham, Kelantan

Mali

D. SoumanoRecherche AgronomiqueDe SotubaB.P. 258Bamako

Mozambique

A. D. MalithanoFaculty of AgricultureUniversity of Eduardo MondlaneC.P. 257, Maputo

Niger

A. MounkailaSection ArachideCNRA/TarnaB.P. 240, Maradi

Nlgaria

C. HarknessInstitute for Agricultural ResearchAhmadu Beilo UniversityPMB 1044, Zaria

S. M. MisariInstitute for Agricultural ResearchAhmadu Bello UniversityPMB 1044, Zaria

Senegal

J. GautreauInstitut Senegalais de Recherches AgricolesCNRA de Bambey

O. De PinsInstitut Senegalais de Recherches AgricolesCNRA de Bambey

Sudan

M. A. Ali Agricultural Research CorporationDirector General's OfficeWad Medani

H. M. IshagAgriculture Research CorporationGezira Research StationWad Medani

Tanzania

A. BoltonODA Oilseeds TeamAgricultural Research InstituteP.O. Box 509Mtwara

A. L. DotoUniversity of Dar es SalaamDepartment of Crop ScienceP.O. Box 643Morogoro

323

N. FivawoResearch DivisionMinistry of AgricultureP.O. Box 7091Dar es Salaam

J. M. TeriUniversity of Dar es SalaamDepartment of Crop ScienceP.O. Box 643Morogoro

Thai land

T. CharoenwatanaFaculty of AgricultureKhon Kaen UniversityKhon Kaen

A. Na LampangField Crop DivisionDepartment of AgricultureBangkhen, Bangkok

D. TiyawaleeFaculty of AgricultureChiang Mai UniversityChiang Mai

USA

M. K. BeuteDepartment of Plant PathologyNorth Carolina State UniversityRaleigh, NC 27650

W. V. CampbellDepartment of EntomologyNorth Carolina State UniversityP.O. Box 5215Raleigh, NC 27650

D. CumminsAssociate Planning DirectorPeanut CRSPGeorgia Experiment StationExperiment, Georgia 30212

R. 0. HammonsUSDA-SEACrops Research UnitCoastal Plain StationP.O. Box 748Tlfton, Georgia 31793

C. R. JacksonPlanning DirectorPeanut CRSPGeorgia Experiment StationExperiment, Georgia 30212

A. J. NordenAgronomy DepartmentUniversity of FloridaGainesville, Florida 32611

D. M. PorterUSDA-SEAPeanut Research UnitTidewater Research CenterSuffolk, Virginia 23437

D. H. SmithTexas Agriculture Experiment StationTexas A & M University SystemP.O. Box 755Yoakum, Texas 77995

H. T. StalkerDepartment of Crop ScienceNorth Carolina State UniversityRaleigh, NC 27650

J. C. WynneDepartment of Crop ScienceNorth Carolina State UniversityRaleigh, NC 27650

Venezuela

B. MazzaniCENIAP-IIAAP. Postal 4653Maracay, 20101

Zimbabwe

C. L. HildebrandCrop Breeding InstituteP.O. Box 8100Causeway

ICRISAT

ADMINSTRATION

L. D. Swindale, Director GeneralJ. S. Kanwar, Director of ResearchJ. C. Davies, Director for International Cooperation

GROUNDNUT IMPROVEMENTPROG RAM

P. W. Amin, Entomologisti. S. Campbell, International InternP. J. Dart, Principal MicrobiologistS. L. Dwivedi, Plant Breeder

324

FARMING SYSTEMS RESEARCH PROGRAM

C. N. Floyd, International IntermM. S. Reddy, Agronomist

R. W. Willey, Principal Agronomist

GENETIC RESOURCES UNIT

V. R. Rao, Botanist

WORKSHOP EDITOR:

J. V. Mertin, 6 Watson Street, Fullarton 5063, SouthAustralia

FRENCH INTERPRETERS

Mrs. T. N. RainaM-19 Greater Kailash I New Delhi, India

Mrs. Pushpa SinghalAsian African Legal

Consultative Committee27 Ring Road, Lajpat Nagar IVNew Delhi, India

A-0023

325

A. M. Ghanekar, VirologistR. W. Gibbons, Principal Plant Breeder and Program

LeaderT. Goto, International InternD. McDonald, Principal Plant PathologistV. K. Mehan, Plant PathologistA. B. Mohammad, EntomologistJ. P. Moss, Principal CytogeneticistP. T. C. Nambiar, MicrobiologistD. J. Nevill, International InternS. N. Nigam, Plant BreederD. V. R. Reddy, Principal VirologistD. C. Sastri, CytogeneticistA. K. Singh, CytogeneticistP. Subrahmanyam, Plant PathologistJ. H. Williams, Principal Physiologist

ICRISAT

International Crops Research Institute for the Semi-Arid Tropics

ICRISAT Patancheru P.O.

Andhra Pradesh 5 0 2 3 2 4 , India

vokils

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