Crop management Effect of planting time, lopping, and N fertilization on growth and

yield of traditional rice variety C14-8 in the Andaman Islands, India 18

Integrated pest management—insects Relationship between farmers' early- and late-season insecticide

Analysis of factors influencing farmers' insecticide sprays 20 Efficiency of a natural biocontrol agent for brown

sprays 19

planthopper 21

lntegrated pest management—other pests Rice stem nematode Ditylenchus angustus development and

survival 21

An efficient inoculation method for rice blast 23 A computer-aided, alternating current-based feeding monitor for

Five researchers named outstanding young women rice

INGER-Myanmar: a success story 26 Breeding rice to improve the health of women and children 26 Improving rice farming in the Mekong Delta of Vietnam 26 IRRI introduces small, powerful harvester 26 High science-low tech: using " heuristics " in integrated pest

ADB supports rainfed lowland rice research 27 Rainfed Lowland Rice Research Consortium: new advanced

Ten IRRI breeding lines released in eight countries in 1994 28

scientists 25

management 27

center for plant physiology 27

Attention collaborators: INGER nurseries available for 1996 28 Biotechnologia Habana '95 29 2nd International Symposium on Systems Approaches for

Rice dateline 30 New IRRI publications 30 Rice literature update reprint service 31 IRRI group training courses for 1995 31 New publications 31 Call for news 31 IRRI address 31

Agricultural Development 30

IRRN 20:2 (June 1995) 3

22nd International Rice Research Conference report 25

detecting activities of plant sap-sucking rice insects 23

IRRI scientist named fellow of the Royal Society 28

Announcements

Instruction for constributors

page 15

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page 24

Germplasm improvement Table 1. Estimated genetic variances, covariances, and heritabilities of milling quality traits in indica rice.

Analysis of seed, cytoplasmic, and maternal genetic effects

Brown Milled Brown Milled Head rice Parameter a rice rice rice rice recovery from

weight weight recovery recovery milled rice

on rice quality traits Shi Chunhai and Zhu Jun, Agronomy Department, Zhejiang Agricultural University (ZAU), Hangzhou 310029, China

We analyzed the genetic effects of seeds, cytoplasm, and the maternal plant on milling quality traits of rice by using the genetic model for quantitative traits of endosperm in cereal crops. Nine cyto- plasmic male sterile (CMS) lines and five restorer lines of indica rice were used in an incomplete diallel cross (9 × 5) during the 1994 early season. Seeds of parents and F 1 s were sown on 28 Mar in the field at ZAU and single plants were trans- planted on 29 Apr at 20- × 20-cm spacing, with 24 plants per plot and three replications. Seed samples of parents or F 1 s were taken at maturity from eight plants in the middle of the plot. Quantita- tive traits were measured for each sample of parents, F 1 s, and F 2 s, using three replications.

by seed, cytoplasmic, and maternal genetic effects (Table 1). Maternal effects were more important than seed effects for brown rice recovery (BRR) and milled rice recovery (MRR). Seed effects mainly controlled brown rice weight (BRW), milled rice weight (MRW), and head rice recovery from milled rice (HRR). Cytoplasmic effects accounted for 4.1-37.3% of the total genetic variation and were significant for all milling quality traits. Significant additive covariance and dominance covariance were not detected, indicating no relationship existed between seed and maternal genetic effects for these milling quality traits.

Seed and cytoplasmic heritabilities were important for BRW, MRW, and HRR, but seed and maternal heritabilities mainly affected MRR. Additive correla- tion was important between BRW and MRW, BRW and MRR, BRW and HRR, and MRW and MRR (Table 2).

Milling quality traits were controlled

V A V D V C

V Dm

C D.Dm V e

V Am

C A.Am

h o 2

h c 2

h m 2

8.285** b

0.499** 2.340**

1.257** 5.308**

–4.264 –0.300 0.183**

0.460** 0.119 0.268*

4.184**

2.128** 0.335**

2.863** 1.270**

–1.547 –0.233

0.146**

0.358**

0.289* 0.179

0.000 2.236**

0.000 3.648** 0.000

–1.329 1.011**

0.000 0.000 0.380

2.598**

19.181** 6.494** 2.373**

19.630** 9.913**

–0.402 –3.863 1.334**

0.373*

0.047 0.382*

160.667** 45.132**

169.232** 0.000

79.054** 0.000

–19.051 5.033**

0.382** 0.000 0.402**

a V A = additive variance, V D = seed dominance variance. V c = cytoplasmic variance, V Am = maternal additive variance, V Dm = maternal dominance, C A.Am = covariance between seed and maternal additive effects, C D.Dm = covariance between seed and maternal dominance effects, V e = variance of residual effects, h o

2 = seed heritability, h m 2 = maternal

heritability, and h c 2 = cytoplasmic heritability. b *, ** = significant at 5 and 1% level, respectively.

Table 2. Correlation components between milling quality traits in indica rice.

Seed Seed Cytoplasmic Maternal Maternal Residual Traits additive dominance correlation additive dominance correlation

correlation correlation correlation correlation

BRW and MRW 0.720 ** a 0.540** 0.477** 0.509** 0.426** 0.100 BRW and BRR 0.000 –0.093* 0.378** 0.000 0.032 0.159* BRW and MRR 0.596** –0.334** 0.135** 0.311** –0.001 –0.118 BRW and HRR 0.486** –0.126** –0.253** 0.000 0.041 0.123* MRW and BRR 0.000 –0.251** 0.571** 0.000 0.075 –0.136 MRW and MRR 0.364** 0.009 0.453** 0.145** 0.119** 0.344** MRW and HRR 0.174** 0.175** –0.349** 0.000 0.066 0.123* BRR and MRR 0.000 0.258** 0.496** 0.000 0.264** 0.269** BRR and HRR 0.000 –0.172** –0.393** 0.000 –0.157** –0.059 MRR and HRR 0.314** 0.208** –0.310** 0.000 0.182** –0.008

a *, ** = significant at 5 and 1% level, respectively.

Tall and dwarf near- isogenic lines of indica rice

Lucaihao (T7 and D7) and their parents

characterized were transplanted according to their height in different plots at 15- × 15-cm spacing in 1993.

Shi Chunhai and Shen Zongtan, Agronomy

panicle length, internode length, effective sity, Hangzhou 310029, China flag leaf length and width, plant height, Department, Zhejiang Agricultural Univer-

Agronomic traits (days to heading,

panicles per plant, spikelets per panicle, The effects of the semidwarf gene sd1 on 1,000-grain weight, yield per plant, agronomic traits in indica rice were biomass, and harvest index) were mea- studied using seven tall and dwarf near sured for 20 plants in the middle of the isogenic lines (NILs) bred by semidwarf 8 /

Flag leaf length, plant height, panicle tall varieties (B 7 F 2 ) (see figure). plot.

Tall and dwarf NILs Ainanzai 1 8 / length, and internode length were Liantangzao (T1 and Dl), Erjiuqing 8 / inhibited by the sd1 gene (see table). Liantangzao (T2 and D2), Fulianai 8 / However, the sd1 gene increased the Liantangzao (T3 and D3), Erjiufeng 8 / effective panicles per plant and harvest Liantangzao (T4 and D4), Guangluai 4 8 / index. The yield of dwarf NILs was Liantangzao (T5 and D5), Erjiufeng 8 / higher than that of tall NILs (d = 2.54). Lucaihao (T6 and D6), and Guangluai 4 8 / The sd1 gene did not affect days to

4 IRRN 20:2 (June 1995)

heading, flag leaf width, spikelets per panicle, 1,000-grain weight, or plant biomass.

Pleiotropism of the sd1 gene and the relationship between plant height and effective panicles were shown.

Effects of the semidwarf gene sd1 on agronomic traits were studied using 7 tall and dwarf NILS bred by semidwarf 8 /tall varieties (B 7 F 2 ).

Comparison of tall (T) and dwarf (D) near-isogenic lines for some traits.

T - D Days to Flag leaf Plant Panicle Effective Spikelets/ 1,000- Yield/ Biomass Harvest lines heading height length panicles/ panicle grain plant (g) index

Length Width (cm) (cm) plant (no.) (no.) weight (g) (cm) (cm) (g)

T1- D1 T2 - D2 T3 - D3 T4 - D4 T5 - D5 T6 - D6 T7 - D7 da

–1.85** b

2.35** –2.10* –1.70**

0.80 –0.85 –0.15 –0.50

9.41** 5.67** 7.09** 8.84** 6.30** 5.88** 6.30** 7.07**

–0.18** –0.02 0.09*

–0.02 –0.18** –0.16** –0.10** –0.08

38.40** 36.65** 39.58** 33.62** 39.91** 32.43** 41.30** 37.41**

2.88** 2.88** 1.70** 0.77 0.95** 0.86 1.32** 1.62**

a d = mean difference. b *, ** = significant at 5 and 1% level, respectively.

–1.70** –1.60** –2.05** –3.10** –1.65** –2.40** –2.15** –2.09**

11.50** 21.00**

7.70* –2.40 –4.40

–15.60* 19.35**

5.31

–0.52 –0.60* 0.17 0.11

–2.47** 0.43

–0.90** –0.54

0.78*

0.25 –2.91**

–2.66** –8.12** –4.78** –0.34 –2.54

4.27** 0.02 0.67

–1.10 –7.96** –3.82**

–0.09 7.29**

–0.06** –0.13** 0.00

–0.09** –0.19** –0.08** –0.14** –0.10**

Mutation of rice seeds in high space environment Xu Jianlong, Lin Yizi, and Xi Yongan, Zhejiang Academy of Agricultural Sciences (ZAAS), Hangzhou 310021, China; Jiang Xingcun, Li Jingguo, lnstitute of Genetics, Academia Sinica, Beijing 100101, China

We studied the mutation rates of seeds from japonica waxy rice variety ZR9 carried on a high space balloon for 8 h at 30-38 km above sea level. Two-thirds of the seeds from an individual plant of ZR9 were sealed in a cloth bag and attached to the balloon. The other third was packed using the same method and kept on earth as a check.

We transplanted 767 plants for the space (SP) 1 generation and 100 plants for the check in a field at 20- × 15-cm spacing. One panicle from each plant of SP 1 was harvested to produce the SP 2 population. We planted 2,500 plants for SP 2 population and 200 for the check. Various mutant types of SP 2 were harvested randomly and used to develop SP 3 lines. We investigated the character

Table 1. Effect of germination and seed setting of the first generation of ZR9 rice seeds on a high space balloon.

Seeds Germination Germination Seed Seedling Treatment (no.) percentage potential setting rate survival rate

(%) (%) (%) (%)

Kept on earth (control) 200 97.5 70.3 92.3 95.1 Sent to space 1447 78.5 43.1 74.2 67.5

Table 2. Variation of major agronomic characters in the SP 2 generation a . ZAAS, Hangzhou, China.

Character X ± S CV (%)

Plant height (cm) Check 107.2 ± 4.1 3.82

Growth duration b (d) Check 104.3 ± 1.3 1.25

Productive panicles (no.) Check 5.1 ± 1.0 19.61

Panicle length (cm) Check 19.3 ± 1.4 7.25

Grain length (mm) Check 7.3 ± 0.2 2.74

Grain width (mm) Check 3.5 ± 0.1 2.86

Grains/panicle (no.) Check 182.2 ± 27.6 15.15

Fertility (%) Check 92.7 ± 2.6 2.80

1,000-gram weight (g) Check 28.3 ± 1.3 4.59

SP 2 105.5 *c ± 15.2 14.41

SP 2 104.2 ± 4.7 4.51

SP 2 8.7** ± 3.1 35.63

SP 2 21.3* ± 1.9 8.92

SP 2 7.7** ± 0.5 6.49

SP 2 3.7* ± 0.2 5.41

SP 2 200.3** ± 34.6 17.27

SP 2 87.3* ± 7.5 8.59

SP 2 28.5 ± 2.9 10.18

a 50 plants were studied for the check and 200 for SP 2 . b From planting to heading. c *, ** = significant difference at 5

and 1% level, respectively.

IRRN 20:2 (June 1995) 5

Maintainers and restorers identified from local germ-

spaced at 23 × 23 cm on 7 Nov 1994. Standard agronomic and plant protection measures were followed, and 120 kg N/

plasm in Pakistan using IRRI ha and 60 kg P/ha were applied. cytoplasmic male sterile lines Ten plants from each hybrid were

S. S. Ali and M. G. Khan, Rice Research Institute (RRI), Kala Shah Kaku, Lahore, Pakistan before flowering. Spikelet fertility was

labeled. Three panicles from each of these plants were marked and bagged

We are studying the feasibility of hybrid rice seed production under local condi- tions.

Fifteen aromatic and nonaromatic local varieties and lines were crossed during 1993 kharif (wet) season with three wild abortive (WA) cytoplasmic male sterile (CMS) lines from IRRI: IR58025 A, lR62829 A, and IR64608 A. Forty-five F 1 hybrids and their male parents and three isogenic maintainers

calculated as a percentage of filled grains. Five spikelets from the upper part of each panicle were collected before anthesis and fixed in 70% alcohol. Two to three anthers from each spikelet were placed together on a glass slide, squashed in 1% potassium iodide solution, and screened for sterile and fertile pollen. Fertile pollens were deeply stained, fully developed, and round.

Male parents of the hybrids showing 100% pollen and spikelet sterility were

Maintainer and restorer lines a identified for IRRI CMS lines at RRI, Kala Shah Kaku, Lahore, Pakistan. 1994.

Spikelet fertility of hybrids with particular CMS line

lR58025 A lR62829 A lR64608 A Pollen parent

47456 49744 Basmati 385 PK4112 4048-3 Besudi Basmati 370 4029 A 4029 B KS282 IR6 4029-2 4029-3 33608 35904

M PR PR M PR PR M PR PR M PR R R PR PR

M PR M M PR PR M M PR PR PR R R PR PR

M R M M M PR PR PR PR M M R R PR R

a R = restorer, PR = partial restorer, and M = maintainer.

Restorers showed 81-100% pollen and spikelet fertility. The rest were classified as partial restorers.

Among the 45 hybrids tested, 47456 and PK4112 were potential maintainers and 4029-2 and 4029-3 were restorers for all three CMS lines. The other pollen parents behaved differentially for the CMS lines (see table). This shows that marked cytoplasmic nuclear interaction exists and expression of restorer genes varies with the genetic background of female parents.

The maintainer lines identified are being used in a backcrossing program for inducing cytoplasmic male sterility in local materials. Restorer lines 4029-2 and 4029-3 will be used to develop new hybrid combinations.

Regeneration of plantlets from protoplasts of Dongxiang wild rice (Oryza rufipogon) Zhu Deyao, Wan Yong, Shen Xianhua, Pan Hao, Ding Xiaohua, and Yin Jianhua, Rice Research Institute, Jiangxi Academy of Agricultural Sciences, Nanchang 330200, China

Dongxiang wild rice is distributed in northeastern China. The Chinese Acad- emy of Agricultural Sciences confirmed that it belongs to O. rufipogon. No one has previously reported plant regenera- tion from its protoplast-derived calli.

6 IRRN 20:2 (June 1995)

expression of SP 1 and SP 2 generations and average values of correlation herita- bility between individual SP 2 plants and SP 3 lines.

The germination rate, germination potential, seed setting rate, and seedling survival rate of the seeds recovered from the balloon were all lower than those of the check kept on earth (Table 1). Some characters of the SP 1 population, such as plant height, the panicle type, and grain color, had variations after heading.

Mutation frequency was 3.4%. In SP 2 , nine major agronomic characters showed larger segragations (Table 2), and the braodness and range of variations surpassed those of SP 1 . The mutation frequency increased to 4.3%. The check ZR9, however, grew evenly, and all characters still kept their original heritable characteristics with no segragation. The correlation heritability was high between individual SP2 plants and those in SP 3 lines. Variations included by exposure to high space can be heritable.

IRRN REMINDER

Multiple submissions. Normally, only one report for single experiment will be accepted. Two or more items about the same work submitted at the same

time will be returned for merging. Submitting at different times multiple notes from the same experiment is highly inappropriate. Detection will

result in the rejection of all submissions on that research.

were transplanted in rows of 30 plants designated as potential maintainers.

Dehulled seeds were surface-sterilized and cultured on N6 medium. After 3 wk, light yellow calli were transferred to AA liquid medium and incubated on a rotary shaker at 120 rpm to establish cell suspension. The culture was incubated at 27 °C in the dark. Protoplasts were isolated from the suspension culture after 2-3 d of subculturing in an enzyme mixture (pH 5.8) containing 0.2% pectolyase Y-23 (w/v), 1 % macerozyme (w/v), 1% cellulase Onozuka R-10 (w/v), 0.5% cellulase Onozuka RS (w/v), MES (5 mM), MgCl 2 • 6 H 2 O (30.83 mg/liter), and 7.2% glucose (w/v).

Suspension cells were incubated for 5-6 h in the enzymatic mixture and filtered through a 30-µm nylon filter. Protoplasts were collected by centrifug- ing at 500 rpm for 3 min and washed in a

New cytoplasmic male sterile line with lower negative effects of cytoplasm on some quantitative traits in rice Wang Wenming and Wen Hongcan, Rice and Sorghum Institute. Sichuan Academy of Agricultural Sciences (SASS). Luzhou 646100, China

Cytoplasmic male sterile (CMS) lines used in hybrid rice breeding in China have had two cytoplasmic sources. One is derived from wild rice ( O. sativa L. f. spontanea Roschev.) and the other from an indica cultivar. To diversify the cytoplasmic background of hybrid rice, we developed CMS lines with new cytoplasm derived from a japonica source.

plants with white and shriveled anthers and aborted pollens in the F 2 population of a japonica/indica cross: 83-k 52 /Lu Hongzao 1 //Zhen Xinzhan 2. These sterile plants were then backcrossed with maintainers as recurrent parents. Three CMS lines were developed—K Qing A in 1988, K 19 A in 1990, and K 17 A in 1992— and designated as CMS-K lines. Using these CMS lines, four hybrid rice combi- nations have been released, and five more are being tested at provincial and national levels.

In 1986, we found several male sterile

solution containing mannitol (0.4 M) and calli to the regeneration medium. Only CPW mixture.

We transferred 96 protoplast-derived

four albinos were obtained. The others Protoplasts (10 5 / ml) were suspended at 35 °C in a modified RY-2 medium (pH were transferred to solid N6 medium 5.8) that was supplemented with casein supplemented with NAA (0.5 mg/liter), hydrolysate (300 mg/liter), glutamine BAP (1 mg/liter), and ABA (2-5 mg/ (800 mg/liter), 2,4-D (1 mg/liter), NAA

green spots or shoots from 37 calli. ABA incubated at 27 °C in the dark. plantlets from 152 calli and observed dishes were sealed with a parafilm and three green plantlets and 28 albino to cover these flat drops, then the petri ated into young plantlets. We obtained liquid RY-2 medium (2-3 ml) was added the regeneration medium, shoots regener- (50-100 µl per drop). When solidified, grow actively, and upon their transfer to petri dishes (ø 6 cm) on agarose balls developed embryogenic calli continued to The protoplast mixture was cultured in white and becoming compact. Well- sucrose (w/v), and 0.8% agarose (w/v). the calli started to grow slowly, turning (1 mg/liter), zeatin (0.5 mg/liter), 13% liter). One week later, more than half of

The first cell divisions were observed increased the frequency of regeneration within 4 d, and microcolonies of the cells of protoplast-derived calli. developed into macroscopic calli after a month.

Cytoplasmic effects a on yield components of early-season hybrid rice.

CMS Grain yield/ Panicle Spikelets/ Filled seeds/ Seed set 1,000-grain type b panicle length panicle panicle percentage weight

CMS-L –6.3** c –2.4** –4.3 –13.7** –10.4** –3.4** CMS-J –11.5** –2.6** –9.5** –19.6** –11.3** –1.6* CMS-Y –4.6 –1.5 –0.1 –10.8** –11.2** –7.0** CMS-S –0.4 –1.3 –0.1 –7.3* –7.3** –2.3** CMS-D 0.1 1.0 2.5 –5.2 CMS-K

–8.2** 1.3

–0.1 –0.1 5.2* –0.1 –6.7** 0.1

CMS-WA –11.8** 1.3 6.7** –0.1 –7.8** –7.8**

aF 1 -bF 1 a Cytoplasmic effects = x 100.

b CMS-J and CMS-L from SAAS breeding materials, CMS-Y from ll-32A. CMS-S from Xie Qingzao A, CMS-D from D Shan A, CMS-W from Zhen Shan 97 A. c *,** = significant at 5 and 1% level, respectively.

bF 1

We evaluated the K-cytoplasmic effects on yield components for hybrid rice in the 1992 early season using seven isogenic-alloplasmic male sterile lines and their maintainer, Lu Hongzao 1 B, crossed with two early-maturing restor- ers. Plots (2.5 m 2 ) were laid out in a complete randomized block design with three replications. CMS-K had a signifi- cant positive effect on spikelets/panicle and a significant negative effect on seed set percentage. For the other traits, the effects were not significant. The six other cytoplasms inducing male sterility showed either significantly negative effects or significant effects on the characters studied (see table).

Compared with Zhen Shan 97 A, K 17 A had the best stigma exsertion (94%), outcrossing rate (73.8%), yield

propagation, and seed production, followed by K Qing A and K 19 A.

The lower negative effects of cyto- plasm and higher outcrossing rate make CMS-K lines valuable for both hybrid rice production and breeding.

Efficiency of different media used in anther culture of hybrid rice N. T. Hoan, Cuu Long Delta Rice Research Institute, Cantho, Omon, Vietnam; Balachandran, N. P. Sarma, and E. A. Siddiq, Directorate of Rice Research, Hyderabad 500030, India

A promising hybrid, IR58025 A/IRBB7, was chosen for use in anther culture. The anthers were inoculated in culture tubes

IRRN 20:2 (June 1995) 7

containing different semisolid media— Response of F 1 hybrid lR58025 A/IRBB7 anthers to different media. a

N6(a), N6(b), Heh5, MSNl, and SK1 — to determine which was the best for cultur- Medium

Anthers Calli Calli Calli Green plants plated obtained subcultured regenerated obtained/

ing hybrid rice. All the calli were trans- ferred to plant regeneration medium SK11

(no.) (no.) (no.) into green 1,000 anthers

N6 (a) (2 mg 2,4-D/liter) 1320 76 65 7 6.2 (MS base + 1 mg NAA + 1 mg BAP +

plants (no.) plated (no.)

0.5 mg kinetin + 30 g sucrose/liter). (5.8) (10.8) N6 (b) (1 mg 2,4-D + 800 65 60 3 4.1

to half strength MS medium without Heh5 500 12 12 4 8.0

The regenerated plants were transferred (8.1) (5.0)

hormones and left for about 3 wk to allow plantlets to harden and to ensure good root growth. Seedlings were then transferred to liquid medium (Yoshida’s solution) for 1 wk before being planted in pots.

between frequency of callus induction and regeneration was recorded (see table). For example, N6(b) had the highest callus induction (8.1 %), but the frequency of regenerated plants from the calli was the lowest among the media. On the other

In general, a negative relationship

MSN1 400 25 3 8.4 (2.4) 28

SK1 1500 59 52 14 10.5

(33.3)

(12) (7.0)

(3.9) (26.9)

a Figures in parentheses indicate percentage of success.

hand, Heh5 induced the lowest percentage produced 10.5 green seedlings per 1,000 of calli (2.4%), but had the highest

Heh5 produced 8.0. Thus, to obtain a regeneration rate. anthers plated, SMN1 produced 8.4, and

A more important index of success is minimum of 150 seedlings, at least 15,000 the percentage of green seedlings ulti- anthers must be inoculated in best medium mately recovered. Using this index, SK1 SK1.

Table 2. Effect of seed size on grain yield and quality of seed produced from different rice grades. TCA, Bihar, India. 1991 and 1992 wet seasons.

Effect of seed size on grain Grain yield (t/ha) 1,000- Germination a Seedling -

yield of rice Treatment grain 1991 1992

(%) length wt (g) (cm)

S. K. Varshney, S. K. Sinha, and B. N. Jha, Seed Technology Department, Tirhut College of Agriculture (TCA), Dholi 843121, Muzaffarpur, Bihar, India

Size Graded 3.4 4.6 22.1 83.8 21.4 Ungraded 2.9 3.4 21.1 82.8 21.5 Undersized 2.5 3.1 19.7 81.5 22.1

Variety Grading is an integral step in seed processing for obtaining quality seeds.

Mahsuri Sujata

2.5 2.8 3.4 4.3

20.5 21.5

82.8 82.5

21.8 21.5

We investigated the effect of seed size on CD (5%) (Size) 0.5 0.6 ns b ns ns

rice yield. CD (5%) (Variety) 0.4 0.5 ns ns CV (%)

ns

Ungraded, graded, and undersized 14.6 17.3 11.6 1.5 11.1

seeds of two popular rice varieties were procured from the seed processing plant at TCA and characterized (Table 1).

Table 1. Characteristics of different grades of seeds used initially in the study. TCA, Bihar, India.

1,000- Germination Seedling Treatment grain (%) length

wt (g) (cm)

Mahsuri Graded 15.7 81 20.8 Ungraded 15.0 72 18.8 Undersized 10.0 50 16.9

Graded 22.5 76 22.7 Ungraded 22.0 76 22.7 Undersized 16.5 52 20.0 SE ± 1.8 5 0.9

Sujata

a Analysis based on angular transformed values. b ns = not significant.

Seeds that passed through a screen with

undersized and those that did not were treatment and the data were analyzed 1.85-mm oblong slits were categorized as

Seed yield was recorded for each

grain weight, germination percentage for categorized as graded. statistically. We also recorded the 1,000-

Seedlings were raised following 400 seeds (100 seeds from each replica- standard practices. The experiment was tion), and seedling length from the seeds laid out in a randomized block design produced with different grades. with four replications and 5 × 2 m 2 plot The graded seed of Mahsuri was size. Two seedlings per hill were

percentage and seedling length (Table 2). transplanted at a spacing of 20 cm superior to the others for germination

the crop. for these attributes in both varieties. mended practices were followed to raise characters. Undersized seeds were poor 1992 kharif (wet) seasons. Recom- ungraded seeds were similar for all each of the six treatments in 1991 and However, for Sujata, graded and between rows and 15 cm within rows for

8 IRRN 20:2 (June 1995)

2 mg NAA/liter)

Seed size affected significantly seed yields for different grades in both varieties (Table 2). The graded seeds gave significantly higher yields than did the other seed grades. Ungraded and undersized seeds did not differ statisti- cally in grain yield. Sujata, however, was significantly superior to Mahsuri for seed yield. The interaction between seed size and variety was not significant, which emphasizes the importance of grading for obtaining quality rice seed and for realizing a variety’s yield potential. Using ungraded or undersized seed to produce a crop may adversely affect yield potential and should be discouraged.

No marked difference existed in the seed quality obtained from different grades of seeds. The main effect of seed size is on the production potential or grain yield and not on the quality of the seeds produced from them.

Competitive ability of medium-duration rices for grain yield N. Kulkarni, Agricultural Research Institute (ARI), Rajendranagar, Hyderabad 500030, India

Varietal mixtures differ in their efficiency in capturing resources to produce higher yields compared with when varieties are grown in pure stands. We studied the competitive ability of all possible mix- tures of five varieties in 1992 and six varieties in 1993. These varieties had long, slender grains and medium duration (130-150 d). Two varieties were mixed in equal proportions, using all possible combinations.

The experiment was laid out in a randomized block design repeated three times during 1992 and 1993 wet seasons. Each entry was planted in a six-row plot, 5.4 m in length, and spaced at 15 cm between and within rows. One-month- old seedlings of the mixtures and of the pure varieties were planted in 1992 and 45-d-old seedlings in 1993.

Grain yield data and percent increase over best pure varieties and check Surekha were recorded (Table 1). In 1992, two varietal mixtures—RDR536 + Surekha and RDR536 + Saleem—yielded

Table 1. Grain yield of varietal mixtures and pure varieties.

Grain % increase over Varietal mixture/ yield pure variety (t/ha) Best pure Check

variety

1992 RDR536 + Raja Vadlu 8.2 0.0 21.1 RDR536 + Divya 8.0 –2.4 18.2 RDR536 + Surekha 9.4 14.6 39.9 RDR536 + Saleem 9.2 12.2 36.2 Raja Vadlu + Divya 6.8 –9.3 0.3 Raja Vadlu + Surekha 8.0 6.6 19.0 Raja Vadlu + Saleem 7.7 2.7 14.6 Divya + Surekha 7.6 11.7 12.0 Divya + Saleem 7.3 19.3 9.2 Surekha + Saleem 7.2 5.9 5.9 RDR536 8.2 Raja Vadlu 7.5 Divya 5.9 Surekha 6.8 Saleem 6.1

CD 0.8 CV (%) 5.6

1993 RDR536 + Raja Vadlu 5.8 9.3 12.6 RDR536 + Surekha 5.9 9.3 14.1 RDR536 + Saleem 4.9 –9.2 –4.9 RDR536 + RNR 32341 5.7 7.4 11.2 RDR536 + CSR13 6.0 11.1 12.7 Raja Vadlu + Surekha 5.9 15.7 14.1 Raja Vadlu + Saleem 4.8 0.0 1.9 Raja Vadlu + RNR32341 5.6 3.7 7.8 Raja Vadlu + CSR13 5.5 1.9 7.0 Surekha + Saleem 4.8 –5.9 –7.8 Surekha + RNR32341 5.4 0.0 5.6 Surekha + CSR13 5.2 –3.7 1.4 Saleem + RNR32341 5.4 0.0 5.6 Saleem + CSR13 4.5 –1.8 –11.9

RDR536 5.4 Raja Vadlu 4.8 Surekha 5.1 Saleem 4.6 RNR32341 5.4 CSR13 5.4

CD 0.5 CV (%) 4.8

RNR32341 + CSR13 5.3 –1.8 2.1

Table 2. General combining ability effects. a

1992 1993

RDR536 0.280** 0.153** Raja Vadlu 0.004 Divya Surekha –0.001 0.013 Saleem CSR13 RNR32341

0.031

SE (gii) 0.081

–0.006 –0.191**

–0.093* –0.274**

0.038 0.04

a *,** = significant at 5 and 1% level, respectively.

12% more grain than when planted individually and 36% more grain than Surekha. Other varietal mixtures also outyielded the check.

In 1993, Raja Vadlu + Surekha yielded 15.7% more than the best yields

of the sole varieties; RDR536 + Raja Vadlu, 9.3%; RDR536 + CSR13, 11.1%; and collectively, about 13% more than the check. These combinations were phenotypically uniform, which is desir- able. The general combining ability effects are estimated in Table 2, treating the experiment as mechanical diallel. RDR536 in the various mixtures pro- duced more grain and possessed signifi- cantly positive general combining ability effects in both years.

This study revealed superior perform- ance of varietal mixtures compared with that of pure varieties. Therefore, it is worthwhile to test more varietal mixtures to exploit their competitive ability.

Resistance of medium- duration rice cultivars to caseworm and leaffolder H. P. Patnaik, K. M. Samal, and S. Mohapatra, Regional Research Station, Keonjhar 758002, Orissa, lndia

Caseworm (CW) Nymphula depunctalis (Guenée) and leaffolder (LF) Cnaphalocrosis medinalis (Guenée) incidences have been high in recent years in the rice-growing area of the north central plateau of Orissa State, India. We evaluated 12 promising medium-duration (120-135 d) rice cultivars for resistance to these pests during 1992 and 1993 wet seasons (WS).

The experiment was laid out in a randomized block design with three replications. Each cultivar was trans- planted in 4- × 2-m plots. The percentage of leaves damaged by CW was recorded at 30 d after transplanting (DT) and that by LF at 50 DT. For each plot, we randomly selected 20 hills and examined five leaves per hill. Low precipitation (996 mm) in 1992 WS favored LF incidence while high precipitation (1200 mm) in 1993 WS favored CW incidence.

Cultivar RP2327-318 had high insect damage and low yields in both 1992 and 1993. In contrast, cultivar P622-629

IRRN 20:2 (June 1995) 9

soil, av of 3 replicates.) 3 g of root, av of 3 replicates. c Number per 200 cm 3 of significantly different at 5% level by DMRT. b Number per a ln a column, figures followed by the same letter are not

Ghaiya 2 Sarju 49 29.0 a Sabitri 27.0 a 10.0 a Chaite 2 22.0 a 3.6 a Radha 9 19.0 a 6.3 a SIPI 692033 18.0 a 5.3 a Sarju 52 16.0 a 8.0 a Pant 4 15.0 a 2.6 a S499-13-28 13.0 a 4.6 a Chaite 4 Makawanpur Masuli Janaki lR15672-1-86-1-1

NR650-2-3-2-1 Radha

lR5167-3-50-2-1 Bindeshori NR605-9-1-1 NR10136-9-6-21 NR601-18-1-2-13-1 84354-C-PN4 Acheme Masino Radha 7 4.6 a 4.3 a NR806-1-9-3 4.6 a 3.3 a NR601-1-1-3-1-1-2 4.0 a 2.6 a BR203-70-13-2 NR806-2-1-1-1 4.0 a 2.3 a NR604-1-1-2-4-2 3.6 a 4.0 a BR808-17-24 RP1125-604-1-1 3.6 a 2.0 a lR79-21 3.6 a 4.0 a NR604-1-1-2-4-1 3.3 a 4.3 a

Variety Root b Soil c

150.0 b 10.0 a 6.0 a

13.0 a 13.0 a 10.0 a 9.0 a 7.3 a 6.6 a 6.6 a 6.3 a 6.0 a 6.0 a 5.3 a 5.3 a 5.3 a 5.0 a

4.0 a 3.6 a

3.6 a 4.3 a

14.0 a 10.0 a 5.3 a 9.6 a 4.6 a 4.6 a 4.6 a 1.6 a 4.6 a 2.3 a 3.6 a 3.6 a 3.0 a 3.6 a

Reaction of promising medium-duration rice cultivars to CW and LF infestation a at Joshipur, Orissa, India. 1992 and 1993 WS.

Leaf damage (%)

Duration CW LF Cultivar Parentage (d)

Yield (t/ha)

1992 1993 Pooled 1992 1993 Pooled 1992 1993 Pooled mean mean mean

OR709-11 IR36/Suph/lR3880// 120 1.6 20.0 (IET11001)

10.8 20.7 2.0 11.3 2.4 def 4.0 bcd 3.2 CR222/Parijat (5.8) a (26.1) c-e (15.9) (24.2) (6.4) (15.3)

(IET11009) (9.7) (31.8) bcd (20.7) (21.2) (8.8) (15.0) 16.4 23.1 4.0 13.5 4.6 ab 4.6 ab 4.6

(IET11006) 1.3 26.0

(5.3) (30.6) bcde (17.9) (25.8) (13.9) (19.8) 13.6 19.1 6.0 12.5 2.6 de 3.9 cde 3.2

(IET11000) (8.2) (29.3) bcde (18.7) (16.9) (15.9) (16.4) 8.9 2.6 de 3.8 def 3.2

(IET11494) (7.1) (31.8) bcd (19.4) (18.3) (18.3) (18.3)

(IET11765) (1.3) (46.1) a (23.7) (23.9) (17.5) (20.7)

(16.1) (34.4) bc (25.2) (19.5) (6.4) (12.9)

(1.3) (25.1) de (13.2) (23.0) (1.3) (12.1) Lalat Obs.677/IR2071// 125 0.0 34.0 17.0 11.1 6.0

(1.3) (35.4) b 8.5 4.6 ab 4.0 bcd 4.3

(18.3) (18.6) (10.8) (14.7) Sarasa CR94-1512/Ratna 125 3.5 24.0

(8.3) (29.3) bcde (18.8) (20.5) (12.4) (16.4) 13.7 12.3 6.0 10.1 2.6 de 4.5 abc 3.5

Sarathi T90/IR8//W1263 120 2.1 34.0 18.0 8.2 8.0 7.1 3.4 cd 3.4 defg 3.4 (6.6) (35.7) b (21.1) (16.2) (13.9) (15.0)

Srabani Mahsuri/lR30 130 3.6 26.0 14.8 8.5 4.0 6.2 5.0 a 3.8 de 4.4 (10.8) (30.6) bcde (20.7) (10.5) (8.8) (9.6)

P622-629 Pusa456/P502 130 4.8 28.0

P586-6-10 P150/IR20 120

OR698-22 OR165-24-12/Sarathi 120 3.4 24.0 13.7 9.9 8.0

RP233-310 Ratna/ARC10659 120 2.5 28.0 15.2 10.5 10.0 10.2 2.6 de 3.9 cdef 3.2

RP2327-318 Ratna/ARC5981 125 0.0 52.0 26.0 16.5 10.0 13.2 1.6 ef 3.7 defg 2.6

CR712-3-38 TN1/Mahiabankoi 135 10.1 32.0 21.0 11.7 2.0 6.8 5.0 a 4.7 a 4.8

OR378-1 IR2070-414/Mahsuri 120 0.0 18.0 9.0 18.3 0.0 7.6 3.8 c 4.7 a 4.2

Rp6-13/W1268

CD b (P = 0.05) – – ns c 9.1 ns ns ns ns 1.0 0.6 ns

a Figures in parentheses are angular transformed values. In a column, means followed by a common letter are not significantly different at the 5% level by DMRT. b CD = critical difference. c ns = not significant by F-test.

(IET11009) yielded well despite high LF different varieties at IAAS, Rampur, Nepal. 1992. study their reactions to these nematodes. damage in 1992, and cultivars CR712-3- Population densities a (no.) of Hirschmanniella in We evaluated 33 rice genotypes to

38 and P622-629 had high yields in 1993 Screening was done at TAAS in lightly despite high levels of CW damage (see flooded soils with natural infestations of

H. oryzae and H. mucronata. The table). This suggests that these cultivars may be resistant to damage by defoliating experiment was laid out in a randomized insects. complete block design and 5- × 3-m plots

with three replicates during the 1992 rice- growing season. Recommended cultural practices were followed.

Rice genotype reaction to rice root nematode ( Hirschman- niella ) in Rampur, Nepal R. R. Pokharel, Institute of Agriculture and Animal Science (IAAS), Central Campus, Rampur, Nepal

High densities of mixed populations of Hirschmanniella oryza and H. mucronata are commonly found in heavy and frequently irrigated soils in lowland rice areas in the Terai region of Nepal.

10 IRRN 20:2 (June 1995)

The nematode population was assessed at the maximum tillering stage of the rice crop. Four corner hills and one central hill were collected with about 250 cm 3 of soil and mixed to prepare one core sample. From these, 3 g of roots and 200 cm 3 of soil were separated, processed using a blender with modified Baermann trays, and sieved with modified Baer- mann trays. The results were analyzed using ANOVA and DMRT.

None of the varieties were resistant. All had nematode populations inside and outside of the roots (see table). Local variety Ghaiya 2, however, had signifi- cantly more nematodes in its roots than the other varieties and was considered to be the most susceptible.

Prabhat, a very early- Table 1. Yield performance of SBR34-69-1 at different sites in Bihar, India. 1984-93.

maturing rice variety released in Bihar, India Year Site

R. Thakur and R. K. Singh, Plant Breeding Department, Rajendra Agricultural Univer- sity, Pusa 848125, Samastipur, Bihar, India; and R. C. Chaudhary, IRRI

Very early-maturing rice varieties are needed before and after floods in north-

1984 Patna Pusa

1988 Patna Sabour

1989 Patna Pusa

Pusa Sabour

Yield (t/ha) LSD (5%) CV (%)

SBR34-69-1 Check a

ern Bihar, in the wet season, and for the

Pooled mean the monsoon. These varieties are also irrigated summer crop harvested before

1990 Sabour

1.4 1.8 2.7 5.0 2.5 1.3 1.7 2.6 2.1 2.1 2.7 2.3

Summer 1.6 1.6 2.2 4.0 2.2 1.5 2.5 2.1 1.2 1.2 2.2 1.8

0.09 0.61 0.50 0.71 0.43 0.96 0.58 1.18 0.60 0.63 0.60

13.0 19.5 15.7 17.5 19.2 20.0 12.1 26.4 14.2 14.6 14.5

suitable for upland conditions when rain is inadequate.

We began work in the early 1980s to 1989 Pusa 3.4 2.7 0.88 21.9

breed suitable varieties after receiving Sabour 2.5 1.9 0.43 11.7

1990 Pusa 2.5 1.2 0.88 12.9 Dhangain 3.7 2.7 0.72 7.2

Wet season

some materials from IRRI. SBR34-69-1 (IR9201-30-1-3-1-3, derived from

matched the desired duration. It was included in state varietal trials in summer and then in the wet season. It was marginally superior in yield to checks Pusa 2-21 and Pusa 33 across 11 environ- ments in the summer (Table 1), though it matured nearly 2 wk earlier. It yielded significantly more than Sattari or Heera (75-80 d duration) during 1989-93 wet seasons.

making a canopy over the ground that suppresses weed growth (Table 2).

SBR34-69-1 has been named Prabhat. It is semidwarf, matures in 85 d in wet season, and is resistant to bacterial blight. Its grains are long-bold.

IR3033-521-1/IR2061-464-2//IR36)

SBR34-69-1 has droopy lower leaves,

Table 2. Weed-suppressing ability of SBR34-69- 1 in variety × weed interaction trial at Sabour, India. 1994.

Weed dry weight (g/m2)

Set I (July) Set II (August) Culture

SBR34-69-1 SBR36-70-1 ES29-3-3 ES21-2-3 ES28-3-1 ES1-1-2

CV (%) LSD (5%)

4.6 9.5

13.9 13.2 12.2 12.1 20.1 4.7

8.7 32.0 21.2 18.5 19.2 15.7 17.0 3.3

1991 Pusa

1992 Pusa

Sabour

Dhangain

Sabour Dhangain

1993 Pusa Patna Sabour Bikramganj

Pooled mean

2.6 2.5 4.1 2.4 2.0 3.3 4.0 3.8 1.6 5.0 3.1

1.4 1.1 2.2 1.8 1.2 2.5 1.8 2.3 1.1 4.3 2.1

1.04 0.24 0.78

0.9 0.42 1.08

0.6 0.56 2.3 0.61 0.5 ns b

0.5 0.85 1.7 1.39 1.7

19.7 13.1 15.4 10.4 11.1 12.6 15.5

17.1 16.8

a Pusa 2-21 or Pusa 33 for summer. Sattari (1st column) or Heera (2nd column) for wet season. b ns = not significant.

Zhefu No. 7, a mutant indica rice variety of short duration for central and eastern China Shu Qingyao and Xia Yingwu, lnstitute of Nuclear Agricultural Sciences, Zhejiang Agricultural University, Hangzhou 310029, China

Short-duration varieties are preferred for use in the early season (Apr-Jul) in the double-cropped area of central and eastern China. From 1986 to 1991, about 1.2-1.3 million ha of this area were planted each year to the leading short- duration variety, Zhefu 802. Zhefu No. 7 was released in July 1994 as an alterna- tive to Zhefu 802. Both have similar

yield potential and growth duration, but Zhefu No. 7 has superior grain quality and blast resistance. Zhefu No. 7 was bred by mutation induction in which seeds of medium-duration variety Erjiufong were exposed to a 30,000 rad dose of 60 Co gamma rays. Erjiufong, once a popular variety, was highly susceptible to cold and low K content in the soil, which restricted its cultivation. Zhefu No. 7, however, has a 4-5 d shorter growth duration and superior tolerance for cold and low K compared with Erjiufong, making it more adaptive to double-cropped areas. Some differences in morphoagronomic characters exist between Zhefu No. 7 and Erjiufong (Table 1).

Table 1. Yield and morphoagronomic characters of Zhefu No. 7 and its parent Erjiufong at Yuhang, Zhejiang Province, China. 1990.

Yield Plant Panicle Grains/ Spikelet 1,000- Variety (t/ha) height length panicle fertility grain

(cm) (cm) (no.) (%) weight (g)

Zhefu No. 7 5.7 77.0 19.5 93.7 88.5 22.3 Erjiufong 5.6 80.8 20.2 103.6 88.0 22.2

IRRN 20:2 (June 1995) 11

1991 Sabour 1992 Sabour

The average yield of Zhefu No. 7 was was detected between Erjiufong and 6.1 t/ha in most areas, and 7 t/ha in a few

Table 2. Yield performance a of Zhefu No. 7 and check Erjiufong in regional tests in Zhejiang Province,

areas. No significant difference in yield Zhefu No. 7 (Table 2).

China. 1990.

Site Locations Zhefu No. 7 Erjiufong Increase over check (%) (no.) yield (t/ha) yield (t/ha)

Hangzhou 13 5.97 ± 0.49 6.24 ± 0.49 Fuyang 7 5.39 ± 0.40 5.28 ± 0.36 +2.0

–4.4

Shaoxin 4 7.01 ± 0.27 6.78 ± 0.25 +3.3 Ningbo 22 6.56 ± 0.61 6.34 ± 0.59 +3.5 Linhai 10 5.37 ± 0.40 5.17 ± 0.34 +3.8

a No significant difference was detected at 0.05 level between Zhefu No. 7 and Erjiufong in any of the regional tests.

PNR162 (Renu), an early rice variety with superfine grain and multiple resistances S. N. Chakrabarti, Genetics Division, Indian Agricultural Research Institute (IARI), New Delhl 110012, India

After several years in coordinated trials, PNR162 was recommended for release for West Bengal and Orissa states in India during the National Rice Workshop in 1989. The Government of Uttar

Pradesh released it for irrigated areas in Sep 1993. Its potential yield is 8 t/ha in northwestern India and about 9 t/ha in summer (boro) season in West Bengal (Table 1).

The variety has superfine grain, multiple resistances to pests, and other desirable characters (Table 2). It has become popular in many other parts of India because it can fit into various crop rotations. Its moderate cold tolerance makes it suitable in the high altitude

Table 1. Average grain yield (t/ha) of PNR162 in various trials. 1986-92.

Site PNR162 IR36 Ratna Pant 4 Saraju 52

Zone 3 a

Zone 4 a

Zone 6 a

Kerala b

Tamil Nadu b

Punjab b

Haryana b

Jammu and Kashmir a

Tripura a

Uttar Pradesh c

3.5 3.9 4.8 3.3 5.6 4.9 7.9 5.3 4.5 5.0

2.9 3.6 4.3 2.1 5.2 4.2 7.3 2.7 3.6

3.0 4.4 4.7 7.1

5.1 4.4

a Coordinated trials. 1987 wet season. b Coordinated trials, 1986 wet season. c Station trials, 1991-92.

Table 2. Quality characters of PNR162.

Character

plains of Manipur, Arunachal Pradesh,

PNR162 Ratna (check) and parts of Jammu and Kashmir. In coordinated, state, and on-farm

Kernel length (mm) 7.0 6.6 Kernel breadth (mm) 2.0 2.1

trials, the variety outperformed national Length-breadth ratio 3.5 3.2 and local checks (Table 1). Its nonshat- Hulling (%) 79.0 75.0 tering trait provides an advantage over Milling (%) 72.6 Head rice recovery (%) 56.0 Alkali value 4.0 6.0 duration. PNRl62 was developed from 55.0

Ratna, a popular variety of similar

Abdominal white Absent Absent induced)/Basmati 370 through selection the cross Jaya Mutant (gamma radiation

in two diverse environments.

12 IRRN 20:2 (June 1995)

Shanyou Wan 3, a medium- maturing, indica hybrid rice He Shunwu, Hunan Hybrid Rice Research Center, Changsha 410125, Hunan, China

Minghui 63, an elite late-maturing rice restorer line, was used as the female parent in a cross with early-maturing rice restorer line 26 Zhaizao in 1984 autumn. The hybrid was planted that winter in Hainan, China. We treated the seeds harvested from the F 1 plants in 1985 with 60 CO gamma ray (D = 177 R/min, D = 2.2 × 10 4 rad), planted the seeds, and con- ducted pedigree selection. In 1989, an early-maturing mutant plant was chosen and testcrossed with Zhenshan 97 A, with the testcross F 1 hybrid performing very well. This hybrid, named Shanyou Wan 3, was tested in 1990. Its restorer line was named Wan 3. The Crop Variety Release Committee of Hunan Province, China, approved Shanyou Wan 3 for commercial production in Jan 1994.

In 1990, Shanyou Wan 3 was tested in a multilocation trial and yielded an average 7.5 t/ha, 13.0% more than check hybrid Weiyou 64, and 10.3% more than check hybrid Shanyou Gui 33 (both significant at 1% level). It matured 5 d earlier than Shanyou Gui 33 and 4 d later than Weiyou 64. The average grain yield of Shanyou Gui 33 was 7.8 t/ha, 14.9% more than that of check Weiyou 64 in the 1991 Loudi Prefectural Rice Variety Regional Trial, Hunan Province (4 hybrids over 5 locations) (see table). In the 1991 All-China Indica Hybrid Rice Regional Trial, it ranked first in grain yield, with an average of 6.6 t/ha, and matured in 119 d. Compared with the check Shanyou Gui 33, its maturity duration, grain yield, and daily grain yield were 3.7 d longer, and 2.7% and 6.1% more, respectively. In 1992, Shanyou Wan 3 was cultivated for demonstration on 1,333 ha in several provinces and showed high-yielding ability. In 1993, it was planted on 44,667 ha.

has stiff straw, good lodging tolerance, and adaptability to heavy fertilization. The panicles are 22-24 cm long with 120- 130 spikelets per panicle. The seed setting rate is 80-85% and the 1,000-grain

Shanyou Wan 3 is 95-105 cm tall. It

69.5

-

- - -

- - -

- - - - - - - - - - - - - - - - - -

Performance of Shanyou Wan 3. Loudi, Hunan Province, China. 1991.

Plant Panicle Spikelets/ Seed 1,000- Maturity Grain Grain yield Daily grain Daily grain Variety height length panicle set grain duration yield over check yield yield over

(cm) (cm) (no.) (%) weight (g) (d) (t/ha) (%) (kg/ha) check (%)

Shanyou Wan 3 102.0 23.8 125.2 71.4 28.7 116.2 7.76** a 14.85 66.75 8.01 Weiyou 64 (check) 86.3 21.9 98.8 72.3 29.8 109.2 6.75 61.8

a ** = significant at 1% level by Duncan’s SSR test.

weight is about 28 g. It matures in 115- 120 d, about 7-8 d earlier than Weiyou 64, and is grown as a late-cropped rice in various areas. Shanyou Wan 3 has strong resistance to blast and sheath blight. It is tolerant of high temperatures in the early growth stages and of coldness in the late stages. Its milling recovery rate is about 75%, and its eating quality is acceptable.

The hybrid has wide adaptability, yielding well at elevations from 200 to

1,150 m above sea level and in different soils.

Seed production is high. The restorer line, Wan 3, has about a 10-d flowering duration, large panicles, many spikelets per unit area, and heavy pollen load. If the flowering synchronization is good between the parents, more than 3 t of hybrid seed/ha can generally be pro- duced.

For spring seed production of Shanyou Wan 3 in Changsha, Hunan Province, the restorer line is generally seeded in late March. The seeding interval between the CMS line (Zhenshan 97 A) and the restorer line is 5.0-5.3 leaves on the main culm or 20-25 d. For autumn seed production, the restorer line is usually sown in mid-June, with an 11-13 d seeding interval for the CMS line.

Promising rice blast-resistant cultivars M. Saifulla, Plant Pathology Department, Agricultural College, University of Agricul- tural Sciences (UAS), Gandhi Krishi Vignyana Kendra (GKVK), Bangalore 560065, India; B. M. Devaiah, and N. M. Poomnacha, Agricultural Research Station, Ponnampet 571216, S. Coorg, India; and A. Munjunath, Dry Farming Department, UAS

Intan, BKB, PUB, Geerigesanna, and IET7191. We intensively screened rice germplasm for reaction to blast. Intan, which is grown on half of the rice area in the hill zone, was introduced in 1972 and lost its resistance to blast in 1983.

About 1,000 germplasm lines were screened for blast resistance under field conditions. Among the entries tested, NSN(H) 102-1988 was free from both leaf

15-m 2 plot during 1990-92 kharif seasons. NSN(H) 102-1988 was free from both leaf and neck blast from 1990 to 1992.

Using the Standard evaluation system for rice, cultivar DWR4107 scored a maximum of 5 for both leaf and neck blast, and Intan scored a maximum of 5 for leaf blast and 9 for neck blast over the 5-yr study. NSN(H) 102-1988 was free from both leaf and neck blast disease and

and neck blast during 1988 and 1992 kharif performed well in yield trials during 1990- Rice b1ast is a serious disease in Coorg

DWR4107 and 1.9 t/ha for Intan (see for intensive screening with DWR4107 and has been breaking down in some of the 2.7 t/ha compared with 2.5 t/ha for plant height, and duration and was selected District of Karnataka, India. Resistance 92 kharif seasons. It had a mean yield of seasons. It also has desirable grain type,

Performance of NSN(H) 102-1988 at Ponnampet, S. Coorg, India. 1988-92.

table). Intan. These cultivars were screened in a modern and local rice varieties, such as

Leaf blast a (score) Neck blast a (score) Yield (t/ha)

1988 1989 1990 1991 1992 1988 1989 1990 1991 1992 1990 1991 1992 Mean Cultivar

NSN(H) 102-1988 0 0 0 0 0 0 0 0 0 0 2.6 4.0 1.9 2.7 DWR4107 3 0 5 5 0 5 2.2 4.3 0.8 2.5 lntan 7 9 5 5 5 5 5 9 9 1.6 3.3 0.8 1.9 a Scored using the Standard evaluation system for rice.

Luit, a short-duration rice variety for Assam, India T. Ahmed and A. K. Pathak, Regional Agricultural Research Station (RARS), Assam Agricultural University (AAU), Titabar 785630, India

Floods may occur anytime from May to early September in Assam, India. Farm- ers need a short-duration rice variety that yields well and can be harvested before (Feb-May) and after (mid-Sep to early Dec) the floodwaters. Rice farmers in the flood-affected areas until recently grew early-maturing varieties—Culture 1,

Heera, and traditional types—that are low-yielding, have undesirable plant type, and are affected by low temperature at flowering when grown after the flood. A hybridization program was initiated in 1988 to develop short-duration photoperiod-insensitive rice varieties with high yield. Luit (IET13622) was

IRRN 20:2 (June 1995) 13

- -

- - - - -

developed by crossing Heera and Annada.

Luit has a growth duration of 95-100 d and may be grown both before and after the flood, either under wet direct seeding or transplanting. Luit is a semidwarf (91 cm), photoperiod-insensitive variety with well-exserted panicles. Grains are awnless and bold. The variety has a 1,000-grain weight of 26.1 g. Kernels are white, with nonglutinous endosperm and a trace of abdominal white. The milling recovery is 64.5%. Luit is moderately resistant to leaf blast and gall midge.

When transplanted during 1993 kharif (dry) season, Luit significantly outyielded check Heera in all four locations and significantly outyielded check Aditya in three of the four locations tested under the All India Coordinated Rice Improve- ment Project (AICRIP) (Table 1). Under wet seeding, Luit significantly outyielded Heera in nine out of 12 locations and Aditya in three out of 12 locations. Luit yielded a mean 5.0 t/ha under transplant- ing and 2.4 t/ha under wet seeding, ranking first and second in AICRIP trials, respectively.

The mean duration of Luit to 50% flowering was 80 d when transplanted and 71 d when wet seeded, which were 16-18 d more than Heera and 6-9 d more than Aditya (Table 1 ). The variety significantly outyielded Culture 1 (Table 2) in various locations in Assam under both conditions. The mean flowering duration under preflood situation was 69 d for both varieties. Under postflood situation, Luit took 11 d longer than Culture 1 to attain 50% flowering.

Table 1. Yield performance of Luit under transplanting and wet seeding at various locations in the All India Coordinated Rice Improvement Project. 1993 kharif.

Date Date Yield (t/ha) Location sown transplanted LSD (0.05)

Luit Heera Aditya

Transplanted Coimbatore 9 Jun 93 9 Jul 93 4.1 3.5 Trichy 9 Jun 53 9 Jul 93 6.0 DRR, Hyderabad

2.7 2 Jul 93 2 Aug 93 6.2 2.3

Nawagaon 28 Jul 93 26 Aug 93 3.9 0.4 5.0 2.2 Mean

Mean days to 50% flowering 80 64

Wet seeded Mugad Bankura Hatwara Karimganj Titabar Jabbalpur Rewa Jadavpur Ranchi Raizabad Banswara IARl (New Delhi)

Mean Mean days to

22 Jun 93 28 Jun 93 22 Jul 93

4 Sep 93 15 Sep 93 10 Jul 93 17 Jul 93 12 Jun 93 28 Jun 93

6 Jul 93 1 Jul 93

22 Jun 93

50% flowering

6.0 2.7 1.7 1.1 1.3 0.5 3.9 2.9 1.7 2.5 4.3 3.1 1.9 1.0 3.3 1.8 1.1 0.6 1.2 0.5 1.3 1.3 1.0 1.4 2.4 1.6

71 53

Table 2. Grain yield of Luit at various locations in Assam, India. 1991-93.

3.9 3.5 4.2 1.1 3.2

74

3.0 1.9 1.5 3.4 1.3 3.2 1.7 3.0 1.2 0.4 2.1 2.7 2.1

62

0.3 2.1 1.0 0.7

1.5 0.4 0.4 0.6 0.4 1.0 0.6 0.5 0.3 0.4 0.4 0.9

Date Yield (t/ha) Days to 50% flowering

Luit Culture Luit 1

Culture 1

Location Date sown transplanted LSD (0.05)

Preflood Titabar Gerua Mahakal

Mean

Postflood Titabar Titabar Gerua Karimganj Karimganj

Mean

25 Feb 91 14 Mar 92 27 Mar 92

20 Aug 91 9 Sep 91

16 Aug 92 4 Sep 93

26 Aug 93

4.5 3.0

20 Apr 92 3.3 3.6

7 Sep91 4.6 3.5

1 Sep92 3.2 3.9

14 Sep 93 3.3 3.7

2.8 2.5 1.5 2.3

2.8 2.4 2.3 2.9 2.7 2.6

68 80 58 69

70 62 69 58 73 66

65 78 65 69

60 52 50

(Heera) 51 60 55

0.5 0.4 0.7

0.7 0.9 0.6 0.6 0.5

Centro lnternacional de gram’s main objective is to develop Coopération Internationale en Recherche Agricultura Tropical's (CIAT's) upland rice germplasm development strategy E. P. Gulmarães, M. Chatel, Y. Ospina, and J. Borrero, Centro lnternacional de Agricultura Tropical (CIAT) Rice Program, Apartado Aéreo 6713, Call, Colombia

CIAT began breeding upland rice for acid-soil savannas in 1984. The pro-

germplasm with a) tolerance for soil acidity, b) resistance to diseases (mainly leaf and panicle blast), c) resistance to insects (mainly Tagosodes oryziculus ), d) good grain quality (translucent, long and slender), and e) earliness (growth duration less than 115 d). The methodol- ogy used is shown in the figure.

the West Africa Rice Development Association (WARDA) and Centre de

Germplasm is exchanged yearly with

Agronomique pour le Développement (CIRAD-CA) in Africa, IRRI in Asia, and national agricultural research systems (NARS) in Latin America.

North American materials were used in the early days as sources of grain quality.

These introduced lines are planted under acid soil conditions. The best lines are selected and organized in a potential parents nursery, which also has many

14 IRRN 20:2 (June 1995)

- -

- -

-

-

- -

other materials (F 4 , F 5 , F 6 , or advanced lines) identified as good sources for

ated for soil acidity in a special acidic crossing. This set of material is evalu-

and nonacidic strip trial. At this stage, the lines are fully characterized for the most important agronomic uaits. The program has recently been testing all potential parents against the blast line- ages identified in Colombia, analyzing them for genetic diversity at the molccu- lar level through polymerase chain reaction technique. and screening them for aluminum tolerance. These results are analyzed to determine which parents will be used and which crosses are to be made, normally a three-way combination.

acid soils in the savanna. Selection is F 2 and F 4 generations are raised on

based on the priority traits. with lines and plants being the selection units (pedigree method). The F 3 and F 5 generations are advanced at an off-season site by planting the lines under irrigated conditions and

The selected lines are then bulked. This selecting only for highly heritable traits.

site is also used to multiply seeds.

NARS through the International Network Advanced lines are distributed to

for Genetic Evaluation of Rice in Latin America (INGER-LAC) Observational Nursery (VIOAL), along with other lines developed by NARS in the region. To acscss the lines' yield potential, the program collaborates with the local NARS—Corporación Colombiana de Investigación Agropecuaria (CORPOICA)—by running some of the

These lines are exchanged with WARDA, CIRAD-CA, IRRI, and Centro Nacional de Pesquisa-Arroz, Feijao/Emrepsa Brasileira & Pesquisa Agropecuaria

preliminary yield trials in two or three locations within different cropping systems, such as rice monocrop, rice - pasture, and soybean - rice.

This approach has allowed NARS to release varieties in Colombia (Oryzica Sabana 6,1991 and Oryzica Turipana 7. 1992), Bolivia (Sacia-1, 1993), and Brazil (Progresso, 1994). Oryzica Sabana 6 has been used in developing a sustainable agropastoral system for the acid-soil savannas in Colombia. Progresso, released for upland ecosys- tems in Brazil, has yielded 4-5 t/ha under farmers' conditions and has good quality. Oryzica Turipana 7 is the first improved variety released for the north coast region in Colombia. It yields 1.0 t/ha more than the local checks, allowing farmers to produce rice not only for subsistence but also for marketing.

recurrent selection was incorporated Population improvement through

recently into the breeding strategy. The objective is to improve populations for specific traits, such as blast resistance,

These populations are used as sources of tolerance for soil acidity, and earliness.

conventional germplasm flow (see improved segregating material for the

figure).

IRRN REMINDER

Routine research. Riports of screening

trials of varieties, fertilizer, cropping

methods, and other routine observations

using standard methodologies to

establish local recommendations are not

ordinarily accepted. Examples are single-

season, singletrial field experiments.

Field trials should be repeated across

more than one season, or in more than

one location as appropriate. All

experiments should include replications

and an internationally known check or

control treatment.

Flow chart of ClAT's upland

development strategy. rice gemplasm

IRRN 20:2 (June 1995) 15

Crop and resource management

Effects of nitrogen and potas- sium nutrition during late growth stage of rice on translocation of 14 C and grain yield Yong-Rui Wang and Ying-Jie Zhang, Biology Department, School of Life Sciences, Sun Yat Sen University, Guangzhou 510275, China

The effect of late N and K application on the translocation of 14 C from the flag leaf and on grain yield was studied. Four seedlings each of the hybrids W6154s/ DFo and W6154s/Tie-San-Ai (F 1 ) were transplanted into 15-liter pots. Fertilizer treatments were no fertilizer control, basal fertilizer only, basal fertilizer + topdressed N (urea) and K (K 2 SO 4 ) at 5-7 d before panicle exsertion, and basal fertilizer + topdressed N (urea) and K (K 2 SO 4 ) at 5-7 d after panicle exsertion. Basal fertilizer consisted of 2 g each of urea, calcium superphosphate, and potassium sulfate/pot.

14 C-glucose (40-60 µci/ml) was sprayed at 0.05 ml/flag leaf for selected tillers at the milky stage. Two days later, plants were sampled and separated into panicles, flag leaves, rest of green leaves, and culms. The radioactivity of each part was measured using a scintillation counter and expressed as count per minute (CPM). The percentage of 14 C exported from the flag leaf was calcu- lated as:

Total CPM of plant – CPM in the flag leaf

Total CPM of plant × 100

The percentage of 14 C translocated to the panicle was calculated as:

CPM of panicle

Total CPM of plant - CPM of flag leaf

× 100

The 14C accumulation percentage (AP) in the panicle, which reflects higher photo- synthetic rate, more translocation of assimilates, larger sink capacity, and a

16 IRRN 20:2 (June 1995)

Table 1. Effect of N and K nutrition at late growth stage on the percentage of 14 C exported from the flag leaf (1), translocated to the panicle (2), and 14 C accumulation percentage [(1x2)/100] (3) at milky stage of two rice hybrids.

W6154s/DFo W6154s/Tie-San-Ai

1 2 3 1 2 3 Treatment

No fertilizer 50.38 44.88 22.61 57.62 42.43 24.45 Basal fertilizer 73.82 70.83 52.29 62.43 54.63 34.11 Basal fertilizer + N and K

topdressing before panicle exsertion 88.38 81.70 72.21 87.85 78.80 69.23 Basal fertilizer + N and K

topdressing after panicle exsertion 78.88 71.60 56.48 77.59 84.20 65.33

Table 2. Effect of N and K nutrition at late growth stage on yield components and grain yield of two hybrids.

Treatment Filled Filled 1,000-grain Grain

spikelets/panicle spikelets weight yield (no.) (%) (g) (g/hill)

W6154s/DFo No fertilizer 102.5 88.5 22.60 Basal fertilizer 110.3 93.5 22.50 Basal fertilizer + N and K

topdressing before panicle exsertion 119.7 98.4 24.40 Basal fertilizer + N and K

topdressing after panicle exsertion 120.9 97.0 24.30

W6154s/Tie-San-Ai No fertilizer 108.7 65.8 24.50 Basal fertilizer 123.7 78.7 24.00 Basal fertilizer + N and K

topdressing before exsertion 130.9 83.1 25.30 Basal fertilizer + N and K

topdressing after exsertion 137.1 83.4 25.80

8.85 ± 0.48 11.72 ± 0.77

15.80 ± 0.92

14.70 ± 0.69

8.31 ± 0.52 12.62 ± 0.68

14.69 ± 0.88

15.49 ± 0.75

better source-sink relationship, was equal to the ratio of CPM in the panicle to total CPM in the plant multiplied by 100.

the flag leaf and translocated to the Response of rice to nitrogen panicle and the AP in the topdressed and zinc application in a plants were all higher than those that calcareous situation received no fertilizer or only basal fertilizer (Table 1). Filled spikelets per A K. Singh, S. Thakur, and S. K. Singh,

panicle, filled spikelet percentage, 1,000-grain weight, and grain yield of the two rice hybrids were all greater in the topdressed plants than in the control The calcareous soils of northern Bihar, plants (Table 2). India, are markedly deficient in Zn. We

The results indicate that topdressing applied N at different levels (0, 50, 100, N and K at around panicle exsertion is a and 150 kg/ha) with and without Zn to good cultural practice because it en- study the effect on grain and straw yields, hances translocation of assimilates from N and Zn uptake, chlorophyll content, the flag leaf to the panicle during and net return obtained. ripening.

The percentages of 14 C exported from

Agronomy Department, Rajendra Agricul- tural University, Pusa Samastipur, Bihar 848125, India

Sujata was grown during 1992 and 1993 wet seasons at Pusa, Bihar, in a silty loam soil with 0.24% organic C, 173.0 kg available N/ha, 22.8 kg available P/ha, and 54.8 kg K/ha. DTPA extractable Zn content was 0.55 ppm and the pH 8.6.

Uniform doses of 17.6 kg P/ha and 33.2 kg K/ha were applied at the last puddling. All N doses were applied in three splits: 25% at transplanting, 50% at tillering, and 25% at panicle initiation. Zn SO 4 •7H 2 O was applied at 5.8 kg Zn/ha before transplanting.

Rice grain and straw yields increased significantly with more N up to 100 kg/ha (see table). Additional N increased yields marginally. However, when Zn accom- panied N, a significant increase in grain yield was observed up to 150 kg/ha. Yields obtained with 150 kg N/ha alone were statistically at par with those at 100

Yield, N, and Zn uptake, and chlorophyll content as affected by different N and Zn treatments (mean of 2 yr), Bihar, India. 1992 and 1993 wet seasons.

Total uptake Total chlorophyll content Net return N level Yield (t/ha) (kg/ha) ($/ha)

Grain Straw N Zn

N 0 1.7 3.4 27 56

N 100 3.2 5.6 54 113 N 150

3.4 6.0 61 134 N 50+Zn

2.7 4.9 46 120 N 100+Zn

3.4 5.6 60 164 N 150+Zn

3.8 5.8 66 191

0.600 10.23 0.621 85.65 0.818 147.40 0.957 161.20 0.700 90.15 0.937 158.70 1.154 184.30

CD (0.05) 0.3 0.6 7 10 13.80

N 50 2.5 4.5 43 81

kg N/ha with Zn. The addition of Zn at all four N levels increased Zn uptake and chlorophyll content significantly over the corresponding N levels without Zn.

N levels with and without Zn differed significantly with regard to net return (see table). The net return increased significantly up to 150 kg N/ha with and

without Zn. At 150 kg N/ha, the addition of Zn generated a significantly higher net return than did 150 kg N/ha alone. These differences were not significant at the other N levels. To get higher yields and monetary returns, Zn should accompany N rather than applying only higher N doses.

Managing nitrogen fertilizer for deepwater rice R. K. Dutta, J. K. Dey, and I. R. Bhattacharjee, Regional Agricultural Research Station (RARS), Assam Agricul- tural University, North Lakhimpur 787001, Assam, India

Deepwater rice (DWR) responds posi- tively to N application. Few studies, however, have focused on how to make N application more profitable and productive for farmers. We studied ways to improve the efficiency of N fertilizer through management and use of slow- release fertilizers in DWR. The soil had a textural composition of 35.1% sand, 31.8% silt, and 33.1 % clay, bulk density of 1.23, pH 4.8, 2.1% organic C, 4.8 kg P (Bray’s P)/ha, 126.50 kg K/ha, free Fe 2 O 3 0.76%, and CEC 9.7 meq/100 g.

Seeds of LPR96-100, derived from Pankaj/Jagannath/Megheribao, were sown on 25 Mar 1991-93 at 75 kg/ha in rows spaced at 25 cm. The experiment was laid out using a randomized block design in 36-m 2 plots. Fertilizers were applied at 30 kg N/ha, 13.2 kg P/ha, and 24.9 kg K/ha; P and K were applied as

Effect of N fertilizer management on deepwater rice. Assam, India. 1991-93.

Treatment Grain yield (t/ha)

1991 1992 1993 Mean

P and K only Prilled urea (1/2 as basal + 1/2 at tillering) Prilled urea (full dose as basal) Neem-coated urea (full dose as basal) Neem-coated urea (1/2 as basal + 1/2 at tillering) Prilled urea (full dose, deeply placed) Urea supergranules (full dose as basal) Prilled urea (4% N spray at tillering) Prilled urea (4% N spray at tillering and

CV panicle initiation)

CD (0.05)

2.0 2.7 2.7 3.5 4.0 2.2 3.0 3.1 3.2

7.3 0.4

1.2 2.6 2.4 3.4 3.8 2.5 2.9 2.8 3.2

5.9 0.3

1.6 2.7 2.2 3.2 3.3 2.2 2.7 2.8 3.1

6.2 0.2

1.9 2.7 2.4 3.3 3.7 2.3 2.9 2.9 3.2

8.1 0.3

basal doses and N in various forms and at different times (see table). The crop was harvested in mid-December.

More than 2,200 mm of rain fell during the growing seasons. Inundation started in June and water level fluctuated between 0.5 and 1 m up to late August, with occasional rises above 1 m during flash floods. Water thereafter receded to less than 0.5 m in September. No water was left in November. Precautions were taken to keep precise fertilizer treatments during inundation.

Applying neem-coated urea in equal splits (basal and at tillering) recorded the highest grain yield (3.7 t/ha), followed by basally applied neem-coated urea (3.3 t/ ha). Foliar application of urea as a 4% spray either once (2.9 t/ha) or twice (3.2 t/ha) recorded higher grain yields than did a soil application of urea as a single basal dose (2.4 t/ha) or in splits (2.7 t/ha).

Foliar application of prilled urea was as efficient as basally applying urea supergranules.

IRRN 20:2 (June 1995) 17

-

18 IRRN 20:2 (June 1995)

Effect of planting time, lop- ping, and N fertilization on growth and yield of tradi- tional rice variety C14-8 in the Andaman Islands, India S. Singh, Central Agricultural Research Institute, Port Blair 744101, India

Despite several high-yielding rice varieties being introduced in the Andaman Islands of India, local rice

variety C14-8 occupies more than half of the rice area. The variety is tall, highly photoperiod-sensitive, and has a very long maturity period. Farmers lop the foliage once or twice during the vegeta- tive phase to prevent the crop from lodging. Leaves are used as green fodder. We studied how planting time. lopping, and N fertilization affect the growth and yield of C14-8.

Thirty-day-old seedlings of C14-8 were transplanted in prefertilized (NPK)

cement pots (30 × 30 × 30 cm) during the first weeks of Aug, Sep, and Oct 1992 and third weeks of Jun, Jul, Aug, and Sep 1993. The experiment was laid out in a completely randomized design with five replications. Plants in a set from each planting date (except the last one) were lopped 50 d after transplanting. Half of the lopped plants were fertilized with N at 5 g urea/pot and the other half were left unfertilized. Another set from each planting date received no treatments.

Effect of planting time, lopping, and N fertilization on growth, yield, and yield attributes of local rice cultivar C14-8. Andaman Islands, India. 1992-93 wet seasons.

Date of Plant Panicles/ Grains/ 1,000- Spikelet Economic Biological Harvest Leaf Leaf Dry wt/ N N planting height pot panicle grain sterility yield

N use Days yield index area/ area/ tiller uptake harvest efficiency to

vs lopping (cm) (no.) (no.) weight (%) (g/pot) (g/pot) (%) plant tiller (g) (g/pot) index (g/g N) flowering (g) (dm 2 ) (cm 2 ) (%)

1992 wet season Planting in 1st wk Aug

Normal 180 41 119 24.6 25.0 112.0 417.5 26.8 108 253 10.2 3.32 Lopping without N 174 23 101 25.6 25.0 72.1 195.4 37.5 50 208 8.4 1.70 Lopping with N 178 34 115 25.2 23.0 92.7 335.1 28.0 87 251 9.8 2.97

Planting in 1st wk Sep Normal 165 41 134 26.3 13.5 131.3 398.8 33.1 73 192 9.7 3.16 Lopping without N 157 37 78 26.2 19.3 73.2 236.0 31.4 59 172 6.4 1.62

with N 160 38 116 26.0 12.0 120.2 344.7 34.8 72 189 9.1 2.68 Lopping

Planting in 1st wk Oct Normal 152 43 122 25.8 7.5 132.7 331.0 40.8 64 185 7.9 3.00

LSD at 5% 3 7 18 N5 5.8 26.4 57.1 4.8 16 21 1.6 0.52

1993 wet season Planting in 3rd wk Jun

Normal 177 45 120 26.5 28.3 136.1 615.0 22.2 123 243 13.6 3.86 Lopping without N 157 26 118 27.0 21.0 84.4 254.6 33.3 82 234 9.8 1.50 Lopping with N 165 32 106 27.8 17.4 89.2 297.6 30.1 88 251 9.3 1.95

Planting in 3rd wk Jul Normal 164 36 131 26.4 19.3 118.4 400.0 29.6 61 149 11.1 2.50 Lopping without N 147 32 103 27.8 19.3 84.8 254.6 33.4 38 154 8.0 1.50 Lopping with N 150 30 121 26.0 16.0 94.2 268.2 35.0 52 163 8.9 1.81

Planting in 3rd wk Aug Normal 174 41 147 27.5 14.8 164.5 543.0 30.0 58 149 13.4 3.27 Lopping without N 141 26 100 28.2 15.2 70.5 207.5 34.0 30 125 8.0 1.24

with N 151 Lopping

37 86 27.1 19.0 92.0 255.0 36.0 55 177 7.0 1.84

Planting in 3rd wk Sep Normal 166 51 113 26.8 13.4 151.7 439.6 34.5 102 257 8.6 3.17

LSD at 5% 10 6 28 1.7 8.2 26.5 86.7 4.5 20 27 2.8 0.85

44

54

39

49

49

44

60

4

47

62

63

62

67

77

63

60

71

65

6

33.7 145

42.4 145

31.2 145

41.5 140

45.2 140

44.8 140

44.5 135

3.5 3

35.2 180

56.2 180

45.7 180

47.5 160

67.0 160

52.0 160

50.1 140

56.4 140

50.0 140

47.8 132

4.5 7

Crop management

Most of the growth and yield characters were recorded at maturity, except for leaf area character, which was recorded at flowering stage.

reduction in growth parameters (plant stature, biological yield, leaf area/plant, leaf area/tiller, dry weight/tiller, and N uptake) but improved grain yield/pot because of the large increase in grains/ panicle and panicles/pot, greater reduc-

Delayed planting caused significant

tion in spikelet sterility, and greater harvest index, partitioning of N, and N use efficiency (see table).

Lopping the foliage during the vegetative phase (50 d after planting), however, depleted both growth and yield characters (stature, biological yield, leaf area/plant, leaf area/tiller, panicles/pot, and grains/panicle). Fertilization follow- ing lopping, however, markedly im- proved almost all growth and yield

characters associated with productivity, resulting in higher grain yield/pot than lopping without applying N.

Time to maturity was reduced drasti- cally by delaying planting until August. Grain yield could be improved substan- tially by transplanting C14-8 in the last week of August or the first week of September. Cutting leaves followed by 20-30 kg N/ha in early planted crops improved the productivity of C14-8.

Relationship between farm- ers´ early- and late-season insecticide sprays two variables (Table 1). Each cell

sprays. The survey data were tabulated into a 2 × 2 contingency table using these

K. L. Heong and A. A. Lazaro, IRRI

One of the objectives of farmers in using insecticides is to avoid yield losses due to insect pests. Thus, the number and timing of these sprays reflect farmers’ perceptions of the expected impact of insecticides on production. We used farmer survey data sets from Leyte and San Jose, Nueva Ecija, Philippines, and the Mekong Delta, Vietnam, to analyze the relationship between farmers’ early- season sprays and their late-season sprays.

questionnaire were carried out in Leyte in 1990, the Mekong Delta in 1992, and San Jose in 1994. Farmers were asked to recall the timing of insecticide sprays used in the previous season. We catego- rized sprays applied in the first 40 d after crop establishment as early sprays and those applied later than 40 d as late

Interview surveys using the same

contained the frequency of occurrence of the respective attributes. We used the Pearson 2 test for independence to determine the association between spray early and spray late. The null hypotheses was that the two variables, spray early and spray late, are independent.

The expected frequencies for each cell from each survey site were determined by calculating the frequencies expected if no association between the two variables existed. The larger the discrepancy between these expected values and the observed values, the larger the degree of association and thus the higher the value of Pearson 2 (Table 2).

We used Pearson 2 values adjusted for a 2 × 2 contingency table to test for significance. The values were significant in all three surveys. Thus, we rejected the null hypothesis in all cases and concluded that early sprays are closely associated with late sprays.

Table 1. Frequency of early- and late-season insecticide sprays by rice farmers in Leyte and San Jose, Philippines, and the Mekong Delta, Vietnam.

Farmers (no.)

Table 2. Tests of independence between early- and late-season insecticide use and probabili- ties of farmers' spray patterns at 3 sites in the Philippines and Vietnam.

Statistics Leyte San Jose Mekong Delta

n 300 285 685 df 1 1 1

P <0.01 <0.01 0.04

Spray pattern Leyte San Jose Mekong Delta

Early and late 0.71 0.75 0.61 Early only 0.08 0.17 0.21 Late only 0.09 0.02 0.12 No sprays 0.11 0.06 0.06

2 62.2 36.7 4.2

We obtained the predicted probabili- ties of occurrence in each case of the contingency table for the three sites. At all sites, the probability of a farmer spraying both early and late was much higher than the probabilities of the other cases occurring (Table 2), meaning farmers who tended to spray insecticides early tended to spray late as well.

While the analysis may indicate significant association between early and late sprays, it does not provide any information on cause and effect. Farmers who sprayed both early and late may be risk averse, those who tend to use higher inputs, or those who are economically

Location Spray late Do not spray late Total

better off. Research has shown that most early

Spray early Leyte 213 24 237 insecticide sprays are unnecessary and San Jose 215 49 264 Mekong Delta 415 142 557

Do not spray Leyte 28 early San Jose 5

Mekong Delta 84

Total Leyte 241 San Jose 220 Mekong Delta 499

35 16 44

59 65

186

may be avoided. Emphasis to reduce early insecticide use may have the added

63 21

128

300 285 685

value of reducing late insecticide use as well.

IRRN 20:2 (June 1995) 19

Analysis of factors influencing farmers’ insecticide sprays A. A. Lazaro and K. L. Heong, IRRI

Farmers’ overestimation of yield loss due to pests and their perceptions that insecticides are remedies probably account for much of the unnecessary insecticide use in rice. Understanding some of the factors that influence farm- ers’ decisions to spray may improve the development of management strategies.

of 285 rice farmers in San Jose, Nueva Ecija, Philippines, in relation to their knowledge of natural enemies, percep- tions of yield losses due to pest damage, attitudes toward insecticide use, and whether they have undergone training. Farmers were grouped into those who spray early, spray frequently, and those who do neither. Those who applied insecticides within the first 40 d after crop establishment were classified as early sprayers and the rest as nonearly sprayers. Likewise, farmers who applied insecticides more than four times in one cropping season were classified as frequent sprayers and those who sprayed four times or less as nonfrequent sprayers.

assessed based on farmers’ awareness of natural enemies and their roles, and farmers’ perceived effects of insecticides on them. Pest management training was evaluated based on attendance and topics of trainings attended. Attitudes toward insecticide use were grouped into “in favor” and “not in favor” based on their responses to statements on insecticide perceptions. Farmers who perceived that insecticides must be applied to the rice crop, increase rice yields, do not cause pest resurgence, and are effective in controlling pests were classified as in favor.

Knowledge, perception, attitude, and training variables were tested independ- ently for associations with early and frequent spraying variables using the chi- square test.

Associations of knowledge with early and frequent spraying and of training with early and frequent spraying were not

We analyzed insecticide spray patterns

Knowledge of beneficial insects was

20 IRRN 20:2 (June 1995)

Table 1. Associations between spraying behavior and knowledge of natural enemies and perceptions/ attitudes toward insecticide use of farmers in San Jose, Nueva Ecija, Philippines, 1994.

Association n df P

Early spraying with knowledge of natural enemies pest management training perception of yield loss attitude toward pesticide use

Frequent spraying with knowledge of natural enemies pest management training perception of yield loss attitude toward pesticide use

1 1 1 1

1 1 1 1

285 285

285

285 285 285 285

285

2.37 3.01 0.15

26.22

0.08 0.31 4.04

16.36

0.12

0.70 <.01

0.08

0.78 0.58 0.04 <.01

Table 2. Probabilities of farmers’ sprayresponses as affected by yield loss perception and attitude toward insecticide use. San Jose, Nueva Ecija, Philippines, 1994.

Spray frequently

Yield loss due to leaf damage

Response a

frequency Probability

No No Yes Yes

No Yes No Yes

111 57 77 22

0.42 0.21 0.29 0.08

Spray early

Favor insecticides

Response frequency

Probability

No No

Yes Yes

No Yes No

Yes

18 3

216 48

0.06 0.01 0.17 0.76

Spray frequently

Favor insecticides

Response Probability frequency

No No 56 0.20 No Yes 122 0.43

Yes No 10 0.04 Yes Yes 97 0.34

a Farmers with no response were excluded from the analysis.

significant (Table 1). This implies that

attitude variables revealed a tendency for not think yield loss was due to leaf association tests between knowledge and with frequent spraying. Farmers who did farmers’ spray patterns. However, by leaf damage is likewise associated of beneficial insects did not influence The perception that yield loss is caused pest management training and knowledge 0.76 and 0.34, respectively (Table 2).

emphasize changing farmers’ attitudes lack this knowledge. pesticide misuse, strategies need to insecticide use tend to be the ones who current farmer practices and to reduce indirect effect because farmers who favor early as well as frequently. To improve unnecessary spraying, it may still have an training in influencing farmers to spray enemies does not seem to influence important than lack of knowledge and although lack of knowledge of natural favoring insecticide use seem to be more ( c2 = 4.03, P = 0.5). This implies that

Our analyses showed that attitudes enemies to favor the use of insecticides (P = 0.42). farmers without knowledge of natural damage tended not to spray frequently

Attitudes favoring insecticide use that favor insecticide use. These might were highly associated with early and include changing farmers’ perceptions frequent spraying. The probabilities that that insecticides are necessary inputs, farmers who favored insecticide use increase yields, do not harm rice, and are would spray early and frequently were effective in controlling pests.

Number of N. lugens killed by predator L. griseus per hour.

Male predator Female predator

Developmental Morphotype Prey Day Night Day Night stage sex

Prey density Prey density Prey density Prey density

5 10 20 5 10 20 5 10 20 5 10 20

Natural enemies play a primary role in the control of the brown planthopper (BPH) Nilaparvata lugens (Stål). We describe here aspects of the behavior of

Efficiency of a natural biocontrol agent for brown planthopper R. Jeyaraj, T. Thangaraj, S. Ravisankar, M. Rabeeth, and M. Aruchami, Zoology Department-Research Centre, Kongunadu Arts and Sclence College, Coimbatore 641029, India

Laccotrephes griseus (Hemiptera: Nepidae), a BPH predator that has been little studied.

Adult L. griseus were collected from freshwater and maintained in the labora- tory. Prey-predator interaction was determined on individual rice plants in pots, each covered with a 45- × 10-cm cylinder of cellophane paper. Fifth-instar

was not disturbed for an hour. The of 5, 10, or 20 per pot. The experiment introduced using an aspirator at densities N. lugens nymphs and adults were

number of prey killed by the predator was then recorded. Five trials were con- ducted.

L. griseus was an active predator during the day and at night. Both male and female predators consumed all prey types offered. In general, the number of prey consumed increased with density (see table).

L. griseus is commonly found in freshwater bodies. When present in large numbers, the predator is a potent biocontrol agent.

Nymph X 0.20 0.60 1.00 0.40 0.40 0.80 SD = 0.40 0.49 0.63 0.49 0.80 0.40

0.20 0.20 0.60 0.00 0.20 0.40 0.40 0.40 0.49 0.00 0.40 0.49

Adult Brachypterous Male X 0.40 1.00 0.80 0.20 0.40 0.80 0.40 0.60 0.60 0.20 0.40 0.60 SD = 0.49 0.63 0.75 0.40 0.49 0.40 0.49 0.49 0.80 0.40 0.49 0.49

Female X 1.00 1.40 2.00 0.80 1.20 1.80 0.40 1.00 1.60 0.40 1.00 1.40 SD = 0.89 0.49 0.00 0.75 0.75 0.75 0.49 0.63 0.49 0.49 0.00 0.49

Macropterous Male X 0.40 0.60 0.40 0.20 0.40 0.60 0.20 0.20 0.40 0.00 0.20 0.40 SD = 0.49 0.49 0.49 0.49 0.40 0.40 0.40 0.49 0.49 0.00 0.40 0.49

Female X 0.60 0.80 0.80 0.40 0.80 1.00 0.20 0.40 0.60 0.20 0.40 0.60 SD = 0.49 0.75 0.40 0.49 0.40 0.63 0.40 0.49 0.49 0.40 0.49 0.49

Rice stem nematode Ditylenchus angustus devel- opment and survival R. N. Perry, Entomology and Nematology Department, Integrated Approach to Crop Research-Rothamsted, Harpenden, Hertsfordshire, AL5 2JQ, UK

The plant parasitic nematode Ditylenchus angustus is an important pest of both deepwater and lowland rice. A research program, funded by the Levelhulme Trust, has been undertaken to investigate the population dynamics, development, and survival of D. angustus under controlled experimental conditions. Infectivity studies demonstrated that third (J3) and fourth (J4)- stage juveniles and adults were able to infect IR36 rice

seedlings in pot cultures kept under lowland growing conditions. Second- stage juveniles (J2) molt rapidly to J3. It may only be J3, J4, and adults that invade.

Quantitative extraction and viability determination of D. angustus eggs are difficult to achieve accurately. However, eggs of D. angustus hatch readily once J2 development is complete, so accurate assessment of population dynamics is more appropriately done at active, hatched stages. Four months after a suspension of D. angustus from a dis- eased plant was inoculated onto 2-wk-old rice seedlings, the population increased tenfold. No marked variation, however, occurred in the percentage of stages from the original inoculum, with J4 accounting

for 56-64% of the population. Few nematodes were found in the folded leaves of the rice plants. No one specific life cycle stage accumulated as the plant senesced, although J4 always predomi- nated (Fig. 1). With increasing host plant age, the nematodes were found in large numbers at the top of the stems, in the panicles, and frequently accumulated on the seeds. In heavy infestations, nema- todes aggregated to form a cotton wool- like mass on empty seeds or in partially emerged panicles enclosed by folded leaves. The analysis of stages present in freshly harvested seeds showed that between 49 and 72% of the nematodes extracted were J4.

The desiccation survival of J3, J4, and adults was examined at different relative

IRRN 20:2 (June 1995) 21

a Vertical bars are the standard error (SE) of the means. Figures are the means and SE for the total number of nematodes/g wet weight of plant tissue at each of four monthly sampling intervals.

1. Percentage of third-(J3) and fourth-(J4) stage juveniles and adults of D. angustus present at intervals of 1 mo in IR36 plants after inoculation with a suspension of mixed stages (time 0). a

22 IRRN 20:2 (June 1995)

humidities on glass slides, on agar and agarose model substrates, and in infested stems and seeds. J2 were not included because very few survived desiccation, even at high humidity and when pro- tected by plant tissue. Individual nema- todes showed no intrinsic ability to control water loss and survive severe desiccation. Nematodes of all three stages were dependent on relative humidity >80% and/or protection by plant tissue for long-term survival. Although J3, J4, and adults showed similar survival attributes with, for example, more than 25% of each stage surviving in a 5-7-cm-long piece of stem for 2 mo at 80 and 97% relative humidity, J4 had consistently superior survival (Fig. 2). The preponderance of J4 in senescing plants together with superior survival attributes make it probable that J4 will be the principal stage that survives drying and subsequently invades new hosts.

The survival and water loss studies indicate that D. angustus is dependent on environmental conditions to survive dehydration. Protection within plant tissues and high humidities, resulting in an induced slow drying rate, enhances desiccation survival. D. angustus aggregates in dry stems and especially in infested seeds, a further behavioral response to facilitate survival.

mainly between the glumes and the caryopsis. Sterile seeds from heavily infested plants frequently contained masses of coiled, dry D. angustus between the glumes. In one seed, 2,400 nematodes were recorded. Although the empty sterile seeds will probably be lost during threshing, other seeds containing nematodes will remain. However, drying of rice grains to a moisture content of 14% or below before storage will prob- ably be sufficient to eliminate viable D. angustus from seeds.

In seeds, the nematodes were found

2. Percentage of third-(J3) and fourth-(J4) stage juveniles and adults of D. angustus present ( ) and the proportion of each stage that survived ( ) in stems of IR36 plants kept for a) 2 mo and b) 4 mo at 40, 60, 80, and 97% relative humidity.

Research methodology An efficient inoculation method for rice blast D. H. Chen, B. Consignado, and R. J. Nelson, IRRI

Inoculation of pathogen isolates to the host is a fundamental tool for studying genetic aspects of both the pathogen and the host. Various inoculation methods have been developed for plant pathology studies. The spray method has most often been used in studies on rice blast because it is convenient and reproducible results are obtained. This method has limitations, however, because it may kill the plant. In molecular genetic studies, F 2 plants usually must be maintained for DNA extraction and for production of F 3 seeds. To avoid killing susceptible individuals, phenotypic segregation data are often collected by progeny testing, causing a lag in completing the analysis. We report here an efficient blast inocula- tion method for a F 2 mapping population.

To demonstrate this method, two F 2 populations developed from a cross of CO 39 with Tetep were used. Two hundred thirty-five seeds were germi- nated for population 1, and 132 seeds for population 2. Twenty seeds each of CO 39 and Tetep were grown together for inoculation as checks. Seedlings (one per pot) were grown in 5-cm-diam pots in a greenhouse for 21 d before inoculation. Isolate V85094, which was compatible with CO39 but incompatible with Tetep, was selected for this study. Inoculum was prepared from cultures grown on rice polish agar and prune agar. The concen- tration of the inoculum was adjusted to 1 × 10 5 spores/ml in 0.02% Tween 20 solution.

Seedlings were laid down on a bench. The youngest leaf that was at least half expanded was selected for inoculation. A 5-cm portion in the middle of the leaf was marked with a pen, and this portion was pricked in five sites with a pin. To wet the leaf surface, the entire leaf was brushed with water containing 0.02% Tween 20 using a soft artist's brush. The leaf was then wiped with a paper towel until dry. A brush dipped in inoculum was applied to the treated leaf. The inoculated seedlings were transferred to a dew chamber and incubated for 24 h at 26 °C, and then kept in a mist room for 6 d before disease evaluation.

Disease was evaluated using a 0-4 scale where 0 = no visual lesions, 1 = tiny brown pinpoint lesions, 2 = roundish, brown, nonsporulating lesions. 3 = roundish, small, weakly or nonsporu- lating lesions with dark margins, 3+ = large sporulating lesions with dark margins, without the typical spindle shape, and 4 = large spindle-shaped sporulating lesions with or without dark margins. Disease reactions with scores of 0-3 were classified as resistant. while those with scores 3+ and 4 were consid- ered susceptible.

All of the plants of the susceptible parent CO 39 showed infection, while none of the plants of the resistant parent Tetep showed lesions (see table). Con- sistent reactions of the wounded and intact leaf segments were observed. The segregation of population 1 was signifi- cantly different from 3:1 (resistant to susceptible) at both 1 and 5% levels, with an excess of susceptible reactions. The segregation ratio of population 2 was significantly different from the 3:1 at 5%

Disease reactions of two F 2 populations and their parents to isolate V85094 of P. grisea using brushing inoculation method in a greenhouse.

Total Total Disease reaction value seeds seedlings for 3:1 a

(no.) (no.) Resistant Susceptible

F 2 population 1 283 235 147 88 F 2 population 2 164 134 CO 39

89 20

45 20 0 20

Tetep 20 20 20 0

19.417** 5.264*

but not at 1%. The distorted segregation ratio could be because of the many nongerminated seeds in both populations. Lesions on noninoculated portions of leaves were rarely observed, and no seedlings were killed due to inoculation. After disease evaluation, infected leaf parts were removed, and the seedlings were transplanted into plastic pails for produc- tion of F 3 seed. Seedling growth was not affected.

Although the method described here seems tedious compared with spray inoculation, two persons finished inoculat- ing two populations in only one afternoon. By using the brushing method of inocula- tion, we could collect segregation data, extract DNA, and harvest abundant F 3 seeds for all plant genotypes in the popula- tion in the same growing season.

A computer-aided, alternating current-based feeding moni- tor for detecting activities of plant sap-sucking rice insects S. R. Venkitesh, IRRI; P. Fretter and P. G. Markham, Virus Research Department, John lnnes Institute, John lnnes Center for Plant Science Research, Colney Lane, Norwich NR4 7UH, UK

A computer-aided feeding monitor has been developed to study the activities of plant sap-sucking rice insects. The feeding monitor consists of an alternating current (AC) probe for detecting changes in conductivity between the insect and the plant, an analogue-to-digital converter (data translation DT2801 A-D card) fitted to an IBM-compatible personal computer (PC), and logging software to collect the data (BioSoft Oscilloscope) (Fig. 1).

The waveform patterns are character- ized by their frequency and amplitude characteristics. Software is used to view the logged waveforms, to add even markers (Markplot), to summarize statistically the marked events (Markstat), to calculate the frequency spectra of the waveform, and to store characteristic waveform patterns. Graphical output can

*, ** = significant difference at 5 and 1% significance level, respectively. be directed to a color graphics metafile

IRRN 20:2 (June 1995) 23

c 2

1. Computer-aided, AC-based feeding monitor. A = chart recorder, B = AC-based feeding monitor, C = rice plant with “wired” insect, and D = computer.

(CGM) for importing into specialized convenient storage, recreation and graphics packages, such as Lotus Free- comparison of waveform patterns, and lance, or to file in Hewlett Packard (HP) capacity for detailed analysis of very Graphics Language (HPGL) for HP minute feeding events. plotters. The “current” screen may be The computer-aided feeding monitor dumped to an Epson FX80 printer. may be used for a range of insect feed-

By selecting a suitable data acquisition ing-related experiments. For example, rate, the computer can be set to construct we studied the feeding behavior of rice waveform patterns similar to a chart green leafhopper (GLH) Nephotettix recorder. The advantages of using a virescens (Distant) on TN1 and IR62 for computer over a traditional chart recorder 3-h and 6-h periods. Typical waveforms include simplicity in marking and were recorded on the chart recorder as categorizing the different waveform well as on the PC while insects were not patterns generated during long recording feeding, probing, and feeding. Wave- periods, automated statistical analysis, forms were correlated with nonfeeding

2. Average time on each feeding-related activity by 20 N. virescens on a susceptible rice variety (TN1) and a resistant rice variety (IR62) for 3 h and by 12 insects for 6 h.

and probing activities by observing the “wired” insect through a dissection microscope. Waveforms with specific feeding activity, such as phloem feeding and nonphloem feeding (xylem and mesophyll parenchyma), were correlated by the histological examination of salivary tracts in the leaf tissue as well as by testing the chemical nature of the honeydew produced. Five other types of waveforms were also recognized and categorized as miscellaneous waveforms, but these have yet to be correlated with specific activities (waveforms not shown). Measuring the time spent on these activities enables feeding-related activities to be quantified.

TN1 and IR62 and then compared. Twelve GLH were also recorded for 6 h on TN1 and IR62 to see whether any marked differences exist in feeding behavior due to prolonged recordings. The different waveforms recorded on both the chart recorder and computer were classified into nonfeeding, probing, phloem feeding, nonphloem feeding, and miscellaneous waveforms as described above. Noticeable differences were apparent between the 3 h and 6 h record- ings. The differences in time spent probing, phloem feeding, and nonphloem feeding on the varieties were more obvious during 6 h of recording rather than during 3 h (Fig. 2).

Twenty GLH were recorded for 3 h on

24 IRRN 20:2 (June 1995)

News about research collaboration 22nd International Rice Re- search Conference report

More than 250 rice scientists and policymakers participated in the 22nd International Rice Research Conference (IRRC) held 13-17 February at the IRRI research center in Los Baños, Laguna, Philippines. The conference focused on fragile rainfed rice-based environments and featured something new: a research- policy dialogue.

“The world today is unable to provide adequate employment and food for 700 million people,” said IRRI Director General Klaus Lampe in his welcome address to IRRC participants. “The question that must be asked is: how can we feed 10, 15, or 20 billion people in the next century?

“The world rice research community, especially those concerned with the less favorable environments, is burdened with unparalleled responsibility. The solution lies only through very innovative re- search, with very innovative results, that can be put into practice by farmers,” said Dr. Lampe. “We have to act—by planning for far into the future, so that the children born today may have the chance to see the end of the next century.”

The IRRC, held every two to three years, is the world’s premier conference for rice scientists. “Fragile lives in fragile ecosystems: feeding the world’s poor from neglected rice ecosystems” was the conference theme.

Participants assessed progress in rice research and identified new research approaches for reducing constraints and improving productivity and sustainability of less favored and fragile rice-producing areas. The conference provided a venue that encouraged international partnerships to address research challenges—includ- ing ones between researchers and policymakers, who had the opportunity to interact and develop an action plan for promoting key policy-research synergism.

The keynote address was given by Philippine President Fidel V. Ramos, who urged governments to guard against complacency on food security issues.

“Our immediate problem is how to increase rice production to meet the annual demands of feeding 50 million more mouths,” he said.

“It is about time that the developed and developing countries, particularly those in Asia, which depend on rice as the principal source of calories, begin supporting rice research at the national and international levels,” said President Ramos. “Support for agricultural research is essential for our survival in the future.”

Scientists presented more than 80 papers under four topics: risk, gain, and sustainability: constraints to farmer adoption of technology; crop intensifica- tion and diversification, nutrient, soil and water management in lowland rice-based ecosystems; understanding variable environments and modeling crop re- sponse to stresses, including disease and pest management; and rice breeding strategies, applying biotechnology, and managing and utilizing biodiversity in rainfed lowland rice systems. The papers are being published as a proceedings, scheduled for release in late 1995.

Rice Science Award recipients were honored on the first day, with each

The Outstanding Young Women in

awardee giving a research presentation. (See related article.)

The new dimension added to this IRRC was a researcher-policymaker dialogue. “The impact of research is always contingent on the policy environ- ment, particularly in less favorable areas,” said Dr. Robert Zeigler, IRRI’s Rainfed Lowland Rice Program leader and IRRC organizing committee chair- man. “The policy perspectives session was held to help open channels of communication among senior research directors, policymakers, and planners.”

planned. Senior policy officials from through-

out Asia provided perspectives on policies relevant to agricultural research and development. Researcher partici- pants gained an appreciation of how policies relevant to agriculture are developed, and policymakers, in turn,

A publication on this session is being

became aware of major potential break- throughs in less favored environments that may deserve special policy consid- eration.

Five researchers named out- standing young women rice scientists Five researchers from four major rice- growing regions of the world were named as the 1995 Outstanding Young Women in Rice Science at the 22nd International Rice Research Conference,

They are Ms. Mai Thi Mien, Vietnam; Dr. Madeleine Ntibishimirwa, Burundi; Ms. C. A. Rosamma, India; Ms. Iis Syamsiah, Indonesia; and Dr. Yang Xiaoe, People’s Republic of China.

one-half of the labor in producing rice, they are in many countries under- represented among rice scientists,” says IRRI Director General Klaus Lampe. “We initiated the award to encourage women’s involvement in rice research and to promote their professional devel- opment. By doing so, we want to create the awareness needed to recognize the intellectual potential still too often underutilized, if not suppressed.”

Danish International Development

“Although women often provide up to

The awards were cosponsored by the

Agency (DANIDA) and IRRI. Ms. Mai Thi Mien, a plant breeder at

the Food Crops Research Institute, Tuloc Haihung, Vietnam, was cited for develop- ing several outstanding spring rice varieties by integrating conventional and mutation breeding methods. These varieties have improved rice production on thousands of hectares in the Red River Delta of Vietnam.

Dr. Ntibishimirwa, a pathologist and director general of the Institut des Sciences Agronomiques du Burundi, leads the rice improvement program at the University of Burundi. Through her research—often conducted under adverse conditions—she formulated recommen- dations for the integrated management of the organism that causes bacterial sheath rot, an important rice disease.

IRRN 20:2 (June 1995) 25

Ms. Rosamma, an assistant professor of plant breeding and genetics at Kerala Agricultural University in India, has worked on rice improvement that resulted in the release of several high-yielding varieties now planted on more than 50,000 ha in Kerala. These varieties are also used internationally as parental lines in rice improvement programs.

Ms. Iis Syamsiah, a researcher at the Sukamandi Research Institute for Food Crops, Indonesia, specializes in water management and the role of women in rice-based farming systems. More than 1,500 small farm reservoirs have been established in rainfed lowland areas as a result of her work.

Dr. Yang Xiaoe, who is a rice nutri- tion researcher and teacher and an associate professor at Zheijiang Agricul- tural University, People’s Republic of China, was cited for her detailed studies on soil and root interactions that have helped to clarify why hybrid rices outperform ordinary rice varieties.

Each of the scientists received a cash grant to further her research and a travel grant to visit IRRI headquarters in the Philippines and to attend the International Rice Research Conference.

INGER-Myanmar: a success story Myanmar has emerged as the world’s fourth largest rice exporter. One of the factors for its success in this area is the country’s active involvement with INGER (International Network for Genetic Evaluation of Rice), based at IRRI.

At the December 1994 INGER advisory committee meeting held in Myanmar, the Myanma minister of agriculture said that his country had released 26 varieties, supplied through participation in INGER, that are now extensively cultivated in farmers’ fields. “Rice production has jumped from 13 million tons in 1991-92 to 17 million tons in 1993-94,” said the minister. “The target for 1994-95 is set for 19.5 million tons.”

26 IRRN 20:2 (June 1995)

INGER, with 95 countries and 1,000 scientists participating in its activities, is one of the most successful international networks involved in plant germplasm evaluation and utilization. The INGER advisory committee guides rice germplasm exchange, evaluation and use, and provides policy guidelines on safe and unrestricted exchange of germplasm globally.

Breeding rice to improve the health of women and children

More than 2 billion people, mostly women and children, suffer from iron deficiency. When zinc, vitamin A. and iodine insufficiencies are calculated along with iron, more than half the world’s people are affected. Such micronutrient deficiencies now outrank protein-energy malnutrition. However, overcoming these deficiencies may eventually become possible in some regions with the development of new rice types.

An International Conference on Nutrition, convened in 1992 by the United Nations Food and Agriculture Organization and the World Health Organization, urged that an agricultural solution to the problem of micronutrient deficiency be found. In response to this, IRRI began collaborating with scientists at the University of Adelaide in Australia, the United States Department of Agricul- ture’s Nutrition Laboratory at Cornell University, USA, the International Center for Tropical Agriculture (CIAT) in Colombia, and the International Maize and Wheat Improvement Center (CIMMYT) in Mexico to increase the availability of micronutrients in crop staples through plant breeding.

At IRRI, the first stage of the collabo- ration—to survey the mineral content of rices—is under way. “Preliminary results show that several rice varieties contain twice as much iron and zinc as that found in IR36, the most commonly grown high- yielding rice variety,” says Dr. D. Senadhira, an IRRI rice breeder.

Normally humans absorb only 25-30 percent of iron and zinc in rice. Thus, the second stage aims to determine exactly how much of the micronutrients are available in the rice diet. The third stage will seek to develop screening techniques to determine which varieties have the most iron and zinc, then to incorporate these characteristics into new varieties.

“Early results are encouraging,” says Dr. Robin Graham of the University of Adelaide. “Our calculations show that if new rices are developed with twice the iron that can be absorbed by humans, they would considerably improve the iron balance in women and children.”

Improving rice farming in the Mekong Delta of Vietnam

~

An extensive research program on varietal improvement, deepwater rice, integrated nutrient management, and rice- based farming systems is now under way at 40 sites in 11 provinces in Vietnam.

It is the first major nationally executed project under the United Nations system. Selected international executing agencies, such as the United Nations Food and Agriculture Organization, previously handled all United Nations Development Programme (UNDP) projects.

The project, financed by UNDP, will be carried out by the Vietnamese govern- ment with the technical cooperation of IRRI. It aims to strengthen the capabili- ties of the Cuu Long Delta Rice Research Institute (CLRRI) to do research and to develop, verify, and transfer technologi- cal packages through strong scientist-to- scientist collaboration and short-term visits by IRRI scientists.

tists have made a total of 43 visits to CLRRI. Despite limited funds, the project has supported 37 Vietnamese scientists through fellowships and study grants and provided in-country training to 165 BS graduates and technicians. Twenty-nine scientific meetings have been organized, attended by 1,245 scientists, extension workers, and government officials.

After only 2.5 years, 25 IRRI scien-

IRRI introduces small, powerful harvester Stripper-gatherer (SG) harvesters devel- oped at IRRI are now being manufac- tured or field-tested in 12 countries in Asia, Africa, and Latin America.

Designed for use in small ricefields less than half a hectare in size, the SG harvester uses 3 liters of gasoline an hour and can harvest 4 tons of rice grain in an eight-hour working day. Because most rice producers have only one or two small fields, the SG harvester is primarily intended for sale to local contract opera- tors. Costing US$1,800 (without the engine), the SG harvester is estimated to pay for itself in less than 60 days of operation.

in 1993 in the Philippines and Thailand. By mid-1994, commercial production began in the Philippines and Vietnam. The technology was developed in collaboration with the United Kingdom’s Silsoe Research Institute with funding from the UK Overseas Development Administration.

the roles of national agencies, extension workers, manufacturers, and farmers in the transfer of the harvester technology to Indonesia, the Philippines, Thailand, and Vietnam. The aim of the studies, which are supported by the German Agency for Technical Cooperation (GTZ), is to develop efficient ways to transfer the SG technology.

IRRI has delivered SG harvesters to, or has orders from, China, Colombia, Côte d’Ivoire, Ecuador, India, Indonesia, Malaysia, Nigeria, Papua New Guinea, Philippines, Thailand, and Vietnam.

The SG harvester was first field-tested

IRRI and local engineers are studying

High science-low tech: using “heuristics” in integrated pest management -

Scientists at IRRI are evaluating ways to integrate concepts in computer and communication sciences to improve farmers’ pest management practices. A pilot project in Long An Province in Vietnam uses the “heuristics” concept to improve farmers’ decisionmaking

~

processes—for example, to ensure that insecticides are applied only when necessary.

Heuristics—rules-of-thumb stored in computer data bases—are used in solving problems. The computer system searches the data bases and comes up with the “best” solution based on research outputs and principles. A simple rule-of-thumb, for example, is “early-season insecticide spraying for leaf-feeding insects is not necessary.”

This simple rule was developed from several years’ research at IRRI and other national research institutes. Field evaluation experiments carried out in the Philippines, Vietnam, Thailand, Malay- sia, and Indonesia showed that the rule worked in all cases. Many farmers who had conducted experiments to evaluate this rule found it to be true and had stopped early-season insecticide applica- tions.

Prof. Gelia Castillo, IRRI consultant, calls this approach of using a simple rule- of-thumb, “high science—low tech.”

In two districts of Long An Province, the pilot project evaluated the use of media to encourage farmers to experi- ment with this rule. The message was delivered through TV, radio, billboards, posters, pamphlets, and demonstration farms. According to Madame Ngoc, director of plant protection in Long An, at least 60% of the 12,500 farmers in Tan Tru District had stopped early-season insecticide use in the autumn-winter crop of 1994. No pest problem has been reported as a result of using the rule.

ture and IRRI scientists are now studying the impact and sustainability of using heuristics in integrated pest manage- ment.

The Vietnamese Ministry of Agricul-

ADB supports rainfed lowland rice research

The Asian Development Bank (ADB) is contributing US$1.1 million to IRRI in 1995-97 to support the Rainfed Lowland Rice Research Consortium (RLRRC) for Asia. The technical assistance reflects the Bank’s policy of strengthening regional, development-oriented,

~

agricultural research. It will support relevant research on the rainfed lowland rice ecosystem, which makes up about one-fourth of the world’s total riceland.

There are more than 35 million hectares of rainfed lowland rice in Asia, located primarily in eastern India, Bangladesh, and Southeast Asia. Rainfed lowlands are characterized by low rice production (less than 2 tons per hectare), primarily because of floods and drought. Farmers in these areas are among the region’s poorest and have little access to improved technology.

The RLRRC, established in 1991 with ADB support, is composed of the na- tional agricultural research systems of Bangladesh, India, Indonesia, Philip- pines, and Thailand, as well as IRRI. Consortium scientists are undertaking strategic research directions toward principal constraints and opportunities in rainfed lowland rice-based systems. Principal efforts are to improve under- standing of the variable environment, generate improved germplasm tolerant of abiotic stresses and resistant to biotic stresses, and develop sustainable produc- tion alternatives that better utilize natural and applied resources.

Rainfed Lowland Rice Research Consortium: new advanced center for plant physiology

The Indian Council of Agricultural Research (ICAR), New Delhi, has designated as an advanced center for plant physiology research the Department of Crop Physiology, Narendra Deva University of Agriculture and Technol- ogy (NDUAT), Kumarganj, Faizabad, India.

Dr. B. B. Singh, head of NDUAT’s Crop Physiology Department and a key site coordinator for the Rainfed Lowland Rice Research Consortium (RLRRC), will serve as director of the advanced center. Researchers at the Masodha- Kumarganj key site conduct strategic research on the mechanism of submer- gence and salt tolerance physiology in rainfed lowland rice.

IRRN 20:2 (June 1995) 27

Modern training facilities will be developed, additional equipment ob- tained, and technical personnel hired so that the center can provide leadership and training for plant physiologists working in teaching, research, and extension activities at state agricultural universities and ICAR institutes, resulting in a boost for consortium activities.

Ten IRRI breeding lines re- leased in eight countries in 1994 During 1994, 10 IRRI breeding lines were released as varieties in eight countries in Africa and Asia:

Announcements

• IR2793-80-1, a high-yielding line with good grain quality, in Uganda.

• An early-maturing line, IR 156-250- 2-2, as Changu in Malawi.

• Another early-maturing line, IR28125-79-3-3-2, with good grain quality, as Gui 713 in Guangxi Province of China.

• A cold-tolerant and early-maturing line, IR28128-45-2, as Pakhel in Pakistan.

planthopper, IR33059-26-2-2 and IR49517-23-2-2-3-2, in Vietnam.

• IR51672-62-2-1-1-2-1 as Rc18 and IR57301-195-3-3 as Rc20 in the Philippines.

• Two lines resistant to brown

IRRI scientist named the Royal Society

fellow of Dr. Khush has led IRRI’s rice breed- ing research for the past 28 years. During that time, more than 250 breeding lines

Dr. Gurdev S. Khush, principal plant developed at IRRI have been released as breeder at IRRI, has been elected a fellow

developed under his leadership, is now ments. disease and insect resistance. IR64, also made outstanding scientific achieve- early-maturing variety with multiple Commonwealth countries who have 1980s. IR36 was the first high-yielding, composed of 1,126 scientists from British hectares of riceland annually in the Charles II of Britain in 1662, is now was at one time planted to 11 million Society, which was granted its charter by developed under his leadership, IR36, improving natural knowledge. The programs worldwide. One of the varieties of the Royal Society for his work in varieties by national rice improvement

the most widely planted rice variety in

• IR51672-115-2-3-1-3 as BR3 in Brunei.

• An early-maturing line with good grain quality, IR9201-30-1-3-1-3, as Prabhat in Bihar State of India.

IRRI supplies seeds of elite breeding lines to scientists in rice-growing coun- tries all over the world through the International Network for Genetic Evaluation of Rice (INGER) or as requested by scientists in national agricultural research systems (NARS). These lines are evaluated under local conditions and promising ones are used in hybridization programs or released as varieties. To date, NARS have selected more than 300 varieties from germplasm supplied by IRRI.

the world. For his rice varietal improve- ment work, Dr. Khush has been honored with several international awards, including the Japan Prize by the Science and Technology Foundation of Japan.

Dr. Khush, an Indian, holds a doctor- ate in genetics from the University of California, Davis. He is a member of numerous professional societies and a fellow of several scientific academies, including the U.S. National Academy of Sciences, Third World Academy of Sciences, and the Indian Academy of Sciences.

Attention collaborators: INGER nurseries available for 1996 Requests for 1996 nurseries are now being accepted through the International Net- work for Genetic Evaluation of Rice (INGER) (see table).

About 1,000 rice scientists from national agricultural research systems in about 95 countries in Asia, Africa, and Latin America participate in INGER, as do scientists from several of the international agricultural research centers. The best breeding lines and varieties developed at these institutions are combined into a series of observational and yield nurseries for evaluation in about 800 locations.

28 IRRN 20:2 (June 1995)

Established as the International Rice Testing Program in 1975, the objectives of INGER are

• to make the world’s elite rice germplasm available to all rice scientists for direct use or in crosses within breeding programs.

• to provide rice scientists with an opportunity to assess the perform- ance of their own advanced breed- ing lines over a range of climatic, cultural, soil, disease, and insect pest conditions.

resistance to major biotic stresses and tolerance for abiotic stresses.

• to identify genetic sources of

• to monitor and evaluate the genetic variation of pathogens and insect pests.

• to serve as a center for information exchange on how varietal charac- teristics interact with diverse rice- growing environments.

• to promote cooperation and interaction among rice improve- ment scientists.

INGER has been one of IRRI’s most effective programs. Opening the genetic flow among continents and making diverse germplasm available has had a visible impact on the varietal improve- ment programs of national systems and international centers. INGER has pro-

Biotechnologia Habana ‘95

vided more than 38,000 breeding lines and varieties for evaluation since its inception. Of these, 454 have been released as varieties in 57 countries in Asia, Africa, Latin America, and the Caribbean. Each variety contributes an annual average of US$2.5 million to the world economy.

INGER has two nursery types. Ecosystem-oriented nurseries, for each of the rainfed upland, rainfed lowland, irrigated, and flood-prone ecosystems, are made up of observational nurseries for evaluating numerous breeding lines

and yield nurseries for intensively evaluating a few lines in replicated trials. In stress-oriented nurseries, elite germplasm is screened for major biotic (pests and diseases) and abiotic (tempera- ture, moisture, and soil) stresses to identify donors, to recognize their durability, and to study variability in races and biotypes.

Cooperators select the types of nurseries they would like to test, and then INGER provides them with the seeds and field books. Cooperators send the evaluation data back to INGER, where

they are analyzed, interpreted, and put into a report.

on the INGER Advisory Committee, a national coordinator for INGER, or an IRRI liaison scientist. Any of these people will take requests for INGER nurseries. If you are not already a cooperator and need more information, contact Dr. R.C. Chaudhary, INGER global coordinator, IRRI.

Requests should be received by 31 Aug 1995.

Many countries have a representative

INGER nurseries available for evaluation during 1996.

Maturity range (d) Maximum Approximate Type Name Full name entries wt

Tropics Temperate (no.) (kg)

Ecosystern-oriented Irrigated

Yield IIRYN-E International Irrigated Rice Yield Nursery-Early 90-120 115-145 30 4.0 IIRYN-M International Irrigated Rice Yield Nursery-Medium 120-140 145-165 30 4.0

Observational

Rainfed Upland

Observational

Lowland Yield

Observational

Stress-oriented

IIRON

IRHON IRBON IRTON IRFAON

IURON

IRLYN-M

IRLON

IDRON

International Irrigated Rice Observational Nursery 90-140 (consists of 2 modules: very early/early and medium/late)

International Hybrid Rice Observational Nursery 100-140 International Boro Rice Observational Nursery 111-130 International Temperate Rice Observational Nursery 100-150 International Fine-grained Aromatic Rice 100-130

Observational Nursery

International Upland Rice Observational Nursery 90-140 (consists of 2 modules: early and medium)

International Rainfed Lowland Rice Yield Nursery- 125-160 a

International Rainfed Lowland Rice Observational 125-160 a Medium

Nursery (consists of 2 modules: early and medium)

Nursery (consists of 3 modules: submergence, deepwater, and floating)

International Deepwater Rice Observational 110-160 b

115-165 120

100 100 100 100

100

30

100

100

Abiotic Drought IRDTN International Rice Drought-Tolerant Nursery 115-165 Soils IRSSTN International Rice Soil Salinity-Tolerant Nursery 115-165

Biotic Diseases IRBN

IRTN International Rice Blast Nursery International Rice Tungro Nursery

Insects IRWBPHN International Rice Whitebacked Planthopper Nursery IRSBN I nternational Rice Stem Borer Nursery

3.0

4.0 3.0 3.0 3.0

2.0

4.0

2.5

2.0

100 1.5 100 1.5

350 4.0 135 1.5 130 1.5

75 1.0

a Some photoperiod-sensitive entries: b Photoperiod-sensitive.

The Center for Genetic Engineering and Biotechnology, in collaboration with the United Nations Educational, Scientific, and Cultural Organization and the Food

and Agriculture Organization of the United Nations, is sponsoring an interna- tional meeting on biotechnology. The event, with the theme “Biotechnologia Habana ’95: new opportunities in plant, animal, and industrial technology,” will

be held in Havana, Cuba, on 12-17 Nov 1995.

For more information, contact the Organizing Committee, Biotechnology Habana ’95, P.O. 6162, Havana, 10600, Cuba.

IRRN 20:2 (June 1995) 29

2nd International Symposium on Systems Approaches for Agricultural Development The second International Symposium on Systems Approaches for Agricultural Development will be held at IRRI on 6-8 Dec 1995. The objectives of the sympo- sium are to review the status of

New IRRI publications

Heterosis and hybrid rice breeding 1994. 189 pages. US$19.00 in highly developed countries (HDC), US$5.00 in less developed countries (LDC), plus US$6.00 airmail or US$1.50 surface postage.

Commercial exploitation of heterosis in rice has helped China to increase rice varietal yield by 15-20% beyond the level of semidwarf rice varieties. There are indications that heterosis breeding could also help increase rice yields elsewhere.

of the Institute of Field and Garden Crops, The Volcani Center, Israel, Dr. Sant S. Virmani, IRRI plant breeder, has written this monograph as a joint publication of IRRI and Springer-Verlag, Berlin. Dr. Virmani has been actively working on hybrid rice for the past 14 years in collaboration with several countries.

At the invitation of Dr. Rafael Frankel

This monograph reviews the literature on heterosis, male sterility systems, and the outcrossing mechanism in relation to hybrid rice breeding and seed production. It also addresses disease and insect resistance, grain quality, and the current status and further outlook of hybrid rice breeding in different countries.

Plant breeders and students of plant breeding, in general, and hybrid rice breeders, in particular, should find this monograph a valuable addition to hybrid rice literature.

On-farm reservoir systems for rainfed ricelands. 1994. 164 pages. US$31.00 in HDC, US$8.00 in LDC, plus US$4.50 airmail or US$l.SO surface postage.

Lack of water at times of need is the dominant constraint to increasing produc-

30 IRRN 20:2 (June 1995)

applications of systems research and It is organized by IRRI, the Interna- modeling in agricultural research, with tional Consortium for Agricultural specific focus on countries where

Systems Analysis and Simulations in agricultural development is facing major Systems Applications (ICASA), and the

and planning. systems approaches as a tool in research awareness of opportunities for using IRRI.

details, contact Dr. P. K. Aggarwal, collaborative activities and to increase Rice Production Network (SARP). For challenges, and to promote international

Rice dateline 21-23 Aug 2nd Asian Crop Science Conference

Fukui, Japan ............................................... G. Rothschild, IRRI

6-8 Oct France/IRRI Day, Montpellier, France .................................... K. S. Fischer, IRRI

16-20 Oct 3rd International Rice Genetics Symposium, IRRI ...................................... G. S. Khush, IRRI

tivity of most rainfed ricelands. On-farm

Vietnamese scientists in the 1976 Interna- rainfed ricelands. reunification with the participation of important role in alleviating drought in collaboration resumed shortly after rainwater storage systems can play an continued during the 1970s, and direct

Research on these storage systems has tional Rice Research Conference at IRRI. been conducted in Bangladesh, India, The papers in this volume were Indonesia, and the Philippines to deter- presented during the Vietnam-IRRI mine their value in conserving rainwater, Conference held in Hanoi during May improving land productivity, and the

milestone in documenting the progress and impact on farmer income. 1994. The conference was an important

Most of the papers in this publication charting new paths to sustainable growth. were presented at a symposium held in conjunction with the 1993 meeting of the The wild relatives of rice: a genetic Rainfed Lowland Rice Research Consor- resources handbook. 1994. 137 pages. tium. The papers have been extensively USS42.00 in HDC, US$11.00 in LDC, edited and updated. Additional chapters plus US$9.50 airmail or US$2.00 surface have been included to give a full picture postage. of the importance of on-farm reservoirs in rainfed agriculture. One of IRRI’s mandated activities is to

maintain and operate a rice genetic Vietnam and IRRI: a partnership in rice resources laboratory that will make research. 1995. 353 pages. US$65.00 in available to scientists and institutions all HDC, US$17.00 in LDC, plus US$13.00 over the world a global collection of rice airmail or US$2.00 surface postage. germplasm. Conservation and evaluation

IRRI has long recognized the value of important part of fulfilling this mandate. collaborative research, as have the The wild relatives of rice form part of scientists of Vietnam. An early result of the wider gene pool of rice, which can be this partnership was the planting of seeds used for rice improvement. Wild species of IR8 (known as Than Nong 8 in the already have furnished some critically South and Agriculture 8 in the North). important genes for rice improvement. Rapid acceptance of this and many other The efforts of former IRRI geneticist IRRI-derived lines followed. The ex- Duncan Vaughan and national program change of varieties and information scientists to collect wild rice relatives over

of wild rice genetic resources is an

the last six years have resulted in this New publications Call for news carefully illustrated handbook, which draws together a large amount of information on this vital component of rice germplasm conserved in the International Rice Germplasm Center at IRRI.

Rice literature update reprint service Photocopies of items listed in the Rice literature update are available from the IRRI Library and Documentation Service. Reprints of original documents (not to exceed 40 pages) are supplied free to scientists of developing countries. Rice scientists elsewhere are charged US$0.20 for each page or part of a page copied, plus postage. Make checks or money orders payable to Library and Documenta- tion Service, IRRI.

Address requests to Library and Documentation Service, IRRI. E-mail: C.AUSTRIA@CGNET.COM.

Biofertilizer technology, marketing, and usage. M.R. Motsara et al.

Micronutrient sourcebook-cum-directory. H.L.S. Tandon.

Recycling of crop, animal, human and industrial wastes in agriculture. Edited by H.L.S. Tandon.

Individuals, institutions, and organiza- tions are invited to tell readers about upcoming events in rice research or related fields in the Rice dateline. Send announcements to the Editor, Interna- tional Rice Research Notes, IRRI.

IRRI address

Sulphur fertilizers for Indian agriculture. Edited by H.L.S. Tandon.

Order from Fertiliser Development and Consultation Organisation, 204-204A Bhanot Corner, 1-2 Pamposh Enclave, New Delhi 110048, India. Fax: 91-11-

International Rice Research Institute P.O. Box 933 1099 Manila, Philippines Tel: (63-2) 891-1926 Fax: (63-2) 891-1292 Telex:(ITT) 40890 RICE PM E-mail: Postmaster@

6465645. IRRI.CGNET.COM.

IRRI group training courses for 1995 Date Course

IRRI provides a limited number of scholarships for participation in its short- term group training courses for 1995. To be considered for an IRRI-funded scholar- ship, a scientist must be affiliated with a national institution that has an official collaborative agreement with IRRI in a rice-related research and training project. A scientist interested in an IRRI-funded scholarship should apply directly to his or her institution and not to IRRI.

IRRI also accepts scientists from other institutions and agencies for the courses if they are working in rice or rice-related areas. Their applications to participate in courses must be endorsed to IRRI by their employer and must specify funding sources to cover costs. IRRI’s group course training fee is approximately US$1,200/month: this does not include participants’ roundtrip international airfare, enroute expenses, or shipping allowance upon return home. The courses are conducted at IRRI headquarters unless otherwise indicated. For additional information, contact the Head, Training Center, IRRI.

17 Jul-8 Sep Integrated Pest Management a

(University of the Philippines Los Baños)

17 Jul-15 Sep Adaptive Research with a Farming Systems Perspective

14-25 Aug Scientific Programming

14 Aug-3 NOV Genetic Evaluation and Utilization

2-27 Oct Geographic Information Systems

9 Oct-1 Dec Rice Production Research b

(Pathum Thani Rice Research Center, Thailand)

6 Nov- 15 Dec Engineering for Rice Agriculture c

(India Institute of Technology, Kharagpur, India)

13-24 NOV Gender Perspective and Analysis in Rural Development d

(International Institute for Rural Reconstruction, Silang, Cavite, Philippines)

20 Nov-1 Dec Frontiers of Social Science Research Methods for Agricultural Systems Analysis

a University of the Philippines Los Baños, Philippine Rice Research Institute, Southeast Asian Regional Center for Graduate Study and Research in Agriculture, and IRRI. b Thailand Rice Research Institute and IRRI. c India Institute of Technology and IRRI. d International Institute of Rural Reconstruction and IRRI.

IRRN 20:2 (June 1995) 31

Erratum Detection of rice tungro bacilliform virus in nonvector insect species following genomic amplification, by S.R. Venkitesh and H. Koganezawa, 20 (1) (Mar 1995), 35-36.

Two sets of photographs should have been published with the following captions:

1. PCR products resolved in 2% agarose gel, stained with ethidium bromide, and visualized by UV illumination. The DNA template used was lanes 1 and 2 = total genomic DNA from RTBV- infected plant (positive control); lanes 3-12 = total genomic DNA of 10 N. virescens (a) and 10 N. nigropictus (b); lanes 13 and 14 = total genomic DNA from nonviruliferous insects (negative control). M = size marker (100-1000 bp).

2. PCR products resolved in 2% agarose gel, stained with ethidium bromide and visualized by UV illumination. The DNA template used was (a): lane 1 = total genomic DNA from RTBV-infected plant (positive control); lane 2 = total genomic DNA from nonviruliferous insect (negative control); lanes 3 and 14 = total genomic DNA of 12 N. lugens; and (b): lanes 1 and 2 = total genomic DNA from RTBV- infected plant (positive control); lanes 3-12 = total genomic DNA of 10 R. dorsalis; lanes 13 and 14 = total genomic DNA from nonviruliferous insects (negative control). M = size marker (300-1000 bp).

32 IRRN 20:2 (June 1995)

ENVIRONMENT SOCIOECONOMIC IMPACT EDUCATION AND COMMUNI-

CATION RESEARCH METHODOLOGY

General criteria. Scientific notes submitted to the IRRN for possible publication should • be original work, • have international or pan- national relevance, • be conducted during the

be work in progress,

Instructions for contributors

NOTES IRRN categories. Specify the

being submitted should appear. Write the category in the upper right-hand corner of the first page of the note.

GERMPLASM IMPROVEMENT genetic resources

immediate past three years or genetics breeding methods

• have rice environment yield potential relevance, grain quality • advance rice knowledge, pest resistance • use appropriate research diseases design and data collection insects methodology, other pests • report pertinent, adequate stress tolerance data, drought • apply appropriate statistical excess water analysis, and adverse temperature • reach supportable conclu- adverse soils sions. other stresses

Routine research. Reports of ment screening trials of varieties, irrigated fertilizer, cropping methods, rainfed lowland and other routine observations upland using standard methodologies flood-prone (deepwater to establish local recom- and tidal wetlands) mendations are not ordinarily seed technology accepted. Examples are single- season, single-trial field CROP AND RESOURCE experiments. Field trials should MANAGEMENT be repeated across more than soils one season, in multiple soil microbiology seasons, or in more than one physiology and plant nutrition location as appropriate. All fertilizer management experiments should include inorganic sources replications and an internation- organic sources ally known check or control crop management treatment. integrated pest management

Multiple submissions. insects Normally, only one report for a weeds single experiment will be other pests accepted. Two or more items water management about the same work submitted farming systems at the same time will be farm machinery returned for merging. Submit- postharvest technology ting at different times multiple economic analysis notes from the same experi- ment is highly inappropriate. Detection will result in the rejection of all submissions on that research.

category in which the note

integrated germplasm improve-

diseases

Manuscript preparation. Arrange the note as a brief statement of research objec- tives, a short description of project design, and a succinct discussion of results. Relate results to the objectives. Do not include abstracts. Do not cite references or include a bibliog- raphy. Restrain acknowledg- ments.

Manuscripts must be in English. Limit each note to no more than two pages of double- spaced typewritten text. Submit the original manuscript and a duplicate, each with a clear copy of all tables and figures. Authors should retain a copy of the note and of all tables and figures.

Apply these rules, as appropriate, in the note: • Specify the rice production ecosystems as irrigated, rainfed lowland, upland, deepwater, and tidal wetlands. • Indicate the type of rice culture (transplanted, wet seeded, dry seeded). • If local terms for seasons are used, define them by character- istic weather (wet season, dry season, monsoon) and by months. • Use standard, internationally recognized terms to describe rice plant parts, growth stages, and management practices. Do not use local names. • Provide genetic background for new varieties or breeding lines. • For soil nutrient studies, include a standard soil profile description, classification, and relevant soil properties. • Provide scientific names for diseases, insects, weeds, and crop plants. Do not use common names or local names alone. • Quantify survey data, such as infection percentage, degree of severity, and sampling base. • When evaluating susceptibil- ity, resistance, and tolerance, report the actual quantification

of damage due to stress, which was used to assess level or incidence. Specify the mea- surements used. • Use generic names, not trade names, for all chemicals. • Use international measure- ments. Do not use local units of measure. Express yield data in metric tons per hectare (t/ha) for field studies and in grams per pot (g/pot) for small-scale studies. • Express all economic data in terms of the US$. Do not use local monetary units. Economic information should be pre- sented at the exchange rate US$:local currency at the time data were collected. • When using acronyms or abbreviations, write the name in full on first mention, followed by the acronym or abbreviation in parentheses. Use the abbreviation thereafter. • Define any nonstandard abbreviations or symbols used in tables or figures in a footnote, caption, or legend.

Tables and figures. Each note can have no more than two tables and/or figures (graphs, illustrations, or photos). All tables and figures must be referred to in the text; they should be grouped at the end of the note, each on a separate page. Tables and figures must have clear titles that adequately explain the contents.

Review of notes. The IRRN editor will send an acknowledg- ment card when a note is received. An IRRI scientist, selected by the editor, reviews each note. Reviewer names are not disclosed. Depending on the reviewer’s report, a note will be accepted for publication, rejected, or returned to the author(s) for revision.

(continued on back cover)