Seedling and adult plant resistance to yellow rust in Iranian bread wheats

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Table 1. Frequency distribution of 25 Iranian bread wheats overfour host response classes to five pathotypes of P. striiformis

Pathotype Host Response

R* MR MS S

14E176A+ 5 – 9 11134E142A+ 5 2 6 126E210A+ 7 2 4 124E128A– 8 2 4 1164E146A+ 11 1 6 7

*R = Resistance (IT=0-1)MR = Moderately resistance (IT = 2)MS = Moderately susceptibility (IT = 3)S = Susceptibility (IT = 4)

Euphytica 100: 51–54, 1998. 1998 Kluwer Academic Publishers. Printed in the Netherlands.

Seedling and adult plant resistance to yellow rust in Iranian bread wheats

M. Torabi & K. NazariSeed and Plant Improvement Institute, Karaj, Iran

Key words: yellow rust, pathotypes, seedling resistance, adult plant resistance, wheat

Summary

In order to evaluate wheat response to yellow rust, 25 advanced, promising and commercial bread wheatcultivars were tested as seedlings in greenhouse conditions in Karaj, Iran, and as adult plants in field condi-tions at four locations. Five pathotypes of yellow rust, 14E176A+, 134E142A+, 6E210A+, 4E128A- and64E146A+ prevailing in field test locations, were used in the seedling tests. The results showed that some ofthe cultivars have seedling or overall resistance to the pathotypes and some have adult plant resistance. Culti-vars M-70-4 and MV17 were resistant to all pathotypes as seedlings and showed good adult plant resistance.

Introduction

Yellow rust caused by Puccinia striiformis f. sp. trit-ici is the most important disease of wheat in Iranand in the countries of central and west Asia. InIran, epiphytotics of the disease have occurred fre-quently since 1991. The most severe epidemic yearswere 1993 and 1995, when climatic conditions wereextremely favourable for disease development.Several extensively grown cultivars showed suscep-tibility to new pathotypes that appeared duringthese years. The losses observed in some cases sur-passed 30% (Torabi et al., 1995). In Afghanistan al-so, yellow rust is known to be the most serious dis-ease of wheat and barley (Saari & Prescott, 1978). InTurkey, the disease is most prevalent in the coolerareas of eastern Anatolia. In 1990, a severe epidem-ic of yellow rust occurred on the local white wheatcultivar in Balouchestan, Pakistan, causing a loss ofabout US $0.8 million (Ahmed et al., 1991). In Syria,several epidemics of yellow rust have occurred dur-ing the last 10 years. The cultivar Mexipak, whichwas widely grown in 1988, showed a grain yield lossof 29% (Mamluk et al., 1989).

Seedling resistances to P. striiformis in wheat canbe detected in greenhouse tests, whereas adult

plant resistance, which can be detected in the glass-house, appears more commonly in field tests (Well-ings, 1988). Seedling resistances are mostly race-specific and are conditioned by the interaction ofresistance alleles in the host and avirulence allelesin the pathogen. The range of seedling resistancegenes to yellow rust in Iranian wheats is relativelynarrow and consist of Yr6, Yr7, Yr9, and YrA geneswhich are typical for wheats developed and re-leased from CIMMYT germplasm (Dr. R. Johnson,personal communication).



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Table 2. Reactions of some advanced linens and commercial bread wheat cultivars to five pathotypes of yellow rust in the greenhousecondition

Cultivar

Name Pedigree

Pathotype

14E176A+ 134E142A+ 6E210A+ 4E128– 64E146A+

M-72-4 Seri82//P77035/Ald”S” 4 4 2 0 ;NM-70-4 K2340/Sx//mt/Gb/3/... 1 ;N ;N ;N ;NM-70-8 F134-71/Crow”S” 4 3 1 2 3M-70-12 Ti/Pch/5/mt48/3/Wt*3//... 3 2 4 1 3C-70-16 Pk 15841 4 4 4 3 4C-70-20 1-27-6275 x CF 1770 4 4 4 4 4C-70-3 Kvz/Ti7//Maya”S”//Bb/Inia 4 3 3 4 4W-70-6 Maya”S”/Nac 3 0 0 3 3W-70-15 Kauze”s” 3 3 4 3 ;NW-70-7 Trt”S”/Vee”S” 1 3 3 3 2W-70-12 Bow”s”/Nkt 1 3 3 2 ;N,1MV 22 [NS 2568-2x(Krasnodar1xZG... 0,1 4 2 4 0MV 16 {[Martonvasari4xKvz)xPurd... 4 4 4 0 ;NMV 17 Slavia x MV Tf) x Zg 4431 0 2 0 0 0Falat Kvz/B4H0//Kal/Bb 3 4 4 0,TN 0Ghods Rsh/5/Wt/4/Nor 10/K54*2//Fn.. 3 4 4 1 3Hirmand Byt/4/Jar//Cfn/Sr 70/3/Jup”S” 3 4 0 4 0Bezos.. 3 3 0 4 3Maroon Avd X Pchu((28mt54AxN10-

Brv... 3 4 4 4 3Navid 4 0 4 0 0Barakat 4 4 0 4 4Bayat (C271 X WTE – Son 64) X CIR 4 0 3 4 4Rasul 3 0 4 4 0Boulani Local 4 4 4 4 4Morocco 4 4 4 4 4

Seedling resistance can provide ephemeral pro-tection against rust because of the ability of thepathogen to produce new pathotypes with in-creased virulence. However, detection, manipula-tion and presence of seedling resistance in breedingmaterial and the possibility that some gene combi-nations may provide desirable resistance makes re-search on this type of resistance essential.

Adult plant resistance, which has been reportedto be more durable than seedling resistance (Dyck& Kerber, 1985) can also be race-specific (Johnson,1981; McIntosh et al., 1995). Genes for adult plantresistance which are effective against a wide spec-trum of rust pathotypes can provide horizontal re-sistance (Robinson, 1976). The present study wasundertaken to evaluate seedling and adult plant re-sistances of some advanced lines and commercialbread wheat cultivars in the greenhouse and field.

Materials and methods

Yellow rust samples were collected from differentlocations of Iran. Pathotype identification proce-dures were performed according to Johnson et al.(1972). Five pathotypes were selected for use in thegreenhouse tests. A total of 25 advanced, promisingand commercial bread wheat cultivars and two sus-ceptible checks were tested as seedlings in thegreenhouse at Karaj, Iran, and as adult plants in thefield at four locations, Moghan, Sari, Gorgan andZarghan.

For the seedling test, urediniospores of eachpathotype were multiplied on susceptible cultivarBolani in the greenhouse. Seedlings of the cultivarsraised under similar conditions in the greenhousewere inoculated with freshly harvested uredinios-pores of single races dispersed in talc powder when



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Table 3. Field responses of some advanced lines and commercial bread wheat cultivars to yellow rust in four different locations of Iran in1994

Cultivar

Name Pedigree

Location

Moghan Sari Gorgan Zarghan

M-72-4 Seri82//P77035/Ald”S” 5MS 10MS 15S tRM-70-4 K2340/Sx//mt/Gb/3/... 5R 5R 15MS tRM-70-8 F134-71/Crow”S” 30S 0 0 tRM-70-12 Ti/Pch/5/mt48/3/Wt*3//... 5R tMR 50S 0C-70-16 Pk 15841 5R 0 0 0C-70-20 1-27-6275 x CF 1770 5R 0 20S 10MRC-70-3 Kvz/Ti7//Maya”S”//Bb/Inia 5R 0 15S tRW-70-6 Maya”S”/Nac 5R 0 0 0W-70-15 Kauze”s” 5R 0 0 10MSW-70-7 Trt”S”/Vee”S” 5R 0 50S 0W-70-12 Bow”s”/Nkt 5R 5MR 0 tRMV 22 [NS 2568-2x(Krasnodar1xZG... 5R 0 50S 0MV 16 {[Martonvasari4xKvz)xPurd... 20MS 10MS 50S 5MRMV 17 Slavia x MV Tf) x Zg 4431 5R 0 5MR 10MRFalat Kvz/B4 H0//Kal/Bb 5S 40MS 30S tRGhods Rsh/5/Wt/4/Nor 10/K54*2//Fn.. 20S 20MS 100S 20MSHirmand Byt/4/Jar//Cfn/Sr 70/3/Jup”S” 5MS 5MR 10MS tRBezos.. 5S 10MS 75S tRMaroon Avd X Pchu((28mt54AxN10-Brv... 5MS 25S 100S 0Navid 5S 10MS 30MS 20MRBarakat 20S 25MS 100S 40MRBayat (C271 X WTE – Son 64) X CIR 10S 20S 75S 5MRRasul 5R 25MS 50S 10MRBoulani Local 80S 5MS 70S 80SMorocco 50S 20MS 100S 60MS

their first leaves were fully expanded. The inoculat-ed seedlings were incubated for 24 h at 10 °C in darkand saturated moisture conditions to encourageurediniospore germination, penetration and infec-tion. The seedlings were then returned to the green-house and maintained in a day/night period of 16/8 hwith a light intensity of 16000 lux and a temperatureof 15/10 °C. Infection types were recorded on day 14and 19 after inoculation using the 0-4 scale, andwere then classified into R, MR, MS and S accord-ing to the method of McIntosh et al. (1995).

For adult plant tests, the resistance of wheat culti-vars to yellow rust was assessed in field diseasenurseries. Test plots of each cultivar consisted oftwo 1-m rows with two replications. Each plot wasadjacent to a rust spreader row consisting of twosusceptible cultivars. Disease assessments of adultplants were made three times based on the percent-

age leaf area affected by yellow rust and reactiontype.

Results

A total of 5, 7, 9, 10 and 12 cultivars showed low in-fection types (0-2) to pathotypes 14E176A+,134E142A+, 6E210A+, 4E128A– and 64E146A+, re-spectively, in seedling tests (Table 1). This indicatedthe presence of seedling resistance effective againstall pathotypes (Table 2). The remaining cultivarseither showed differential responses or were sus-ceptible.

In field tests, a large variation in disease severityand host response was observed at different loca-tions (Table 3). In general, cultivars with low infec-tion types at seedling stage had resistant or moder-



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ately resistant responses in the field, whereas culti-vars with high seedling infection types to a patho-type showed disease severity between 0 and 100with reactions ranging between resistant to suscep-tible.

Seedling reaction of cultivars was different to dif-ferent pathotypes, but two cultivars, M-70-4 andMV-17, were resistant to all five pathotypes. Theyalso showed good adult plant resistance at all fourlocations.

A shift towards susceptibility was observed inGorgan compared to the other three locations inthe group of susceptible seedling cultivars. Diseaselevel was higher in Gorgan than in Moghan, Sariand Zarghan, and some clear cultivar-location in-teractions observed could be due to the presence ofdifferent pathotypes.

Discussion

The 23 advanced, promising and commercial breadwheat cultivars tested in this study show the presentstatus of yellow rust resistance in Iranian cultivars.The observed shift towards susceptibility in Gorgancompared to the other locations could be mostlydue to differences in environmental conditions.However, race specific effects could also be in-volved.

Many of the cultivars tested here are of CIM-MYT origin and carry Yr9 gene for yellow rust re-sistance (McIntosh, 1979). The pathotypes used inthe seedling test carry virulence for Yr9 gene (Tora-bi, unpublished data). Therefore, cultivars thatshowed susceptible reactions at seedling stagecould be evaluated for the presence of adult plantresistance. Several cultivars carried such a resist-ance. In four locations where the present study wascarried out, presence of pathotypes with several vir-

ulence factors gives a greater opportunity to breed-ers to detect adult plant resistance and select forhigher levels. Whether the adult plant resistancedetected in the tested cultivars will be durable re-mains a question because it is known that someadult plant resistances are also race specific (John-son, 1981; McIntosh et al., 1995).

References

Ahmad, S., A. Rodriguez, G. Farid Sabir, B. Roidar Khan & M.Panah, 1991. Economic losses of wheat crops infected with yel-low rust in highland Baluchistan. MART/AZRI Project Re-search, Report No. 67. ICARDA, Quetta. 15 pp.

Dyck, P.L. & E.R. Kerber, 1985. Resistance of the race-specifictype. In: W.R. Bushnell & A.P. Roelfs (Eds.), The CerealRusts. II, pp. 469-500. Academic Press Inc., Orlando, FL,USA.

Johnson, R., 1981. Durable resistance: Definition of genetic con-trol, and attainment in plant breeding. Phytopathology 71:567-568.

Mamluk, O.F., M.P. Haware, K.M. Makkouk, & S.B. Hanounik,1989. Occurrence, losses and control of important cereal andfood legume diseases in West Asia and North Africa. In: Pro-ceedings of the 22nd International Symposium on TropicalAgriculture Research, pp. 131-140.

McIntosh, R.A., 1979. A catalogue of gene symbols for wheat. In:S. Ramanujam (Ed.), Proceedings of the 9th InternationalWheat Genetics Symposium, Vol. 2, pp. 1299-1309.

McIntosh, R.A., C.R. Wellings & R.F. Park, 1995. Wheat Rusts:An Atlas of Rust Genes. CSIRO, Melbourne, Australia.

Robinson, R.A., 1976. Plant Pathosystems. Springer-Verlag,Berlin. 184 pp.

Saari, E.E. & J.M. Prescott, 1978. Barley diseases and their sur-veillance in the region. In: S. Barghouti, E.E. Saari, J.P. Srivas-ta & G. Chancellor (Eds.), Proceedings of the 4th RegionalWinter Cereal Workshop – Barley, Vol. 2, pp. 320-330. ICAR-DA, Aleppo, Syria.

Torabi, M., V. Mardoukhi, K. Nazari, F. Afshari, A.R. Forootan,M.A. Ramai, H. Golzar & A.S. Kashani, 1995. Effectiveness ofwheat yellow rust resistance genes in different parts of Iran.Cereal Rust and Powdery Mildews Bulletin 23: 9-12.

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Seedling and adult plant resistance to yellow rust in Iranian bread wheats