International Rice Research Newsletter Vol.13 No.4

IRRN GUIDELINES The International Rice Research Guidelines for Newsletter objective is. contributors

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Categories of research reported GERMPLASM IMPROVEMENT

genetic resources genetics breeding methods yield potential grain quality and nutritional value disease resistance insect resistance drought tolerance excess water tolerance adverse temperature tolerance adverse soils tolerance integrated germplasm improvement seed technology research techniques data management and computer

modeling

CROP AND RESOURCE MANAGEMENT

soils and soil characterization soil microbiology and biological N

physiology and plant nutrition crop management soil fertility and fertilizer management disease management insect management weed management managing other pests integrated pest management water management farm machinery environmental analysis postharvest technology farming systems research methodology data management and computer

fertilizer

modeling

SOCIOECONOMIC AND ENVIRONMENTAL IMPACT

environment production livelihood

EDUCATION AND COMMUNICATION

training and technology transfer

communication research information storage and retrieval

research

CONTENTS GERMPLASM IMPROVEMENT

Breeding methods 4 Variations in anther culture-derived lines of Ponni

Yield potential 4 Weight and germination of main and ratoon crop seeds 4 Metroglyph analysis of some upland rice cultures 5 Effect of waxy gene on rice yield components

Grain quality and nutritional value 6 Rice varietal differences in number of brokens

Disease resistance 7 Resistance of rice breeding lines to bacterial blight (BB) and stem rot (SR) 7 Field reaction of IR varieties to rice tungro (RTV)-associated viruses 8 Reaction of International Rice Bacterial Blight Nursery (IRBBN) cultures

9 Field and screenhouse evaluation for resistance to rice tungro (RTV) 9 Reactions of Mahsuri and Sona Mahsuri to blast (Bl)

to an Aduthurai, India, bacterial blight (BB) pathotype

10 Screening new rice selections for reaction to major diseases 10 Bacterial blight (BB) development in rice varieties and screening tests

Insect resistance 11 Incorporation of brown planthopper (BPH) resistance genes from indica

11 Screening rice seedlings for resistance to leaffolder (LF) 12 Field incidence of and host resistance to Angoumois grain moth (AGM)

into japonica rice

Excess water tolerance 12 Breeding for submergence tolerance

Adverse temperature tolerance 13 Screening criterion for cold tolerance at the seedling stage 14 Effect of low temperature on selected rice varieties in Tanzania 15 Response of rice varieties to planting time during the dry season 15 Inheritance of seedling stage cold tolerance in 6 indica and japonica crosses

Adverse soil tolerance 16 Effect of soil alkalinity on yield of genotypes in Kanpur 16 Screening rice entries for coastal salinity and tidal swamp conditions

Integrated germplasm improvement 17 Performance of early Prasanna variety 17 A high-yielding variety for coastal Andhra Pradesh, India 17 Two new varieties from segregation material of IR36 18 Three rice varieties named in Ghana 18 Red Triveni, a promising short-duration variety for India 19 A blast (Bl)-resistant and high-yielding early indica variety 19 OM91: an improved rice variety for high-production irrigated areas 20 Performance of IR42 in deepwater rice areas on the Red River delta in

northern Vietnam

Seed technology 20 Standardizing hybrid rice A line seed production 21 Varietal differences in seed longevity

CROP AND RESOURCE MANAGEMENT

Soils and soil characterization 22 Urea hydrolysis in oxidized and reduced flooded soil

Soil microbiology and biological N fertilizer 23 Influence of P, K, micronutrients, and dolomite on azolla growth 23 Response of flooded rice to green manure 24 Azolla growth under different rice planting methods in Kerala 25 Green manure as N source for flooded rice 26 Mineralization of fresh and dry azolla in the tropics 26 Parthenium as green manure for rice

Physiology and plant nutrition 26 Supply and uptake of urea- 15 N by rice

Soil fertility and fertilizer management

application on rice yield 27 Comparison of prilled urea (PU) and large granule urea (LGU) and time of

28 N management for late transplanting in northwestern India 28 Direct and residual effects of biogas residue application with nitrogen on

29 Effect of azolla green manure on rice yield 29 Green manure to sustain productivity and save nitrogen for rice in a rice -

rice yield

wheat cropping system

Crop management 30 Low-tillage broadcast rice productivity

Disease management 30 Host plants of rice tungro (RTV)-associated viruses 31 Unrecorded weed hosts for Pyricularia oryzae Cav. in India 32 Diseases of deepwater rice in Jorhat District, Assam, India 32 Host plants of ragged stunt virus (RSV) 33 Differential transmission of tungro (RTV) by green leafhopper (GLH)

33 Combined ufra + (Bl) infection in deepwater rice 34 Dot-blot immunoassay (DBI) for detecting rice grassy stunt virus (GSV) 35 Survival of stem rot (SR) fungi 36 Effect of cytozyme on incidence of rice sheath blight (ShB) 37 Host plants of rice grassy stunt virus (GSV) 37 Fungicides to control rice sheath blight (ShB) 38 Effect of N and K on rice sheath rot (ShR) and crop yield

selected on IR54

Insect 38

39 40

40

41

42 42 42

management Using mixtures of buprofezin and cypermethrin or deltamethrin for green leafhopper (GLH) and rice tungro virus (RTV) control Orientation of whitebacked planthopper (WBPH) to scentless rice plants Minimal dosages of buprofezin to control green leafhopper (GLH), whitebacked planthopper (WBPH), and brown planthopper (BPH) Predation by sword-tailed cricket Anaxipha longipennis (Serville) (Gryllidae) on eggs of three lepidopterous pests of rice Effect of insecticide application at different growth stages on rice yield components and rice straw Population trends of striped rice borer in Korea Effect of plant extracts on brown planthopper (BPH) oviposition A synthetic diet for rice leaffolder (LF)

Water management 43 Irrigation schedule for dry season rice 43 Water management studies in rice

Farm machinery 44 Dispenser method for using urea supergranules in transplanted rice 45 Testing a seed drill for upland rice

Environmental analysis 46 Effect of season on rice response, production efficiency, and recovery of

applied N

Farming systems 46 Growth and yield of wet season rice with tilapia fish 47 Pulse crop performance in a rice-based cropping sequence

ANNOUNCEMENTS

47 New IRRI publications 47 New book on rice diseases

GERMPLASM IMPROVEMENT Breeding methods

Variations in anther culture- derived lines of Ponni

S. R. Sree Rangasamy, W. Wilfred Manuel, K. Natarajamoorthy, S. Palanisamy, and M. Gurunathan, Paddy Breeding Station, Tamil Nadu Agricultural University, Coimbatore 641003, Tamil Nadu, India

We studied 10 lines derived by anther culture from Ponni (Mahsuri) in a randomized block design with 3 replications Dec 1986-May 1987. The anther culture-derived lines showed drastic reduction in duration, plant height, and grain yield but increased

Yield potential

Weight and germination of main and ratoon crop seeds

C. A. Rosamma, K. Karunakaran, P. Chandrika, and N. R. Nair, Regional Agricultural Research Station, Pattambi 679306, India

Studies in 1981-85 have indicated that ratooning rice under Kerala conditions is feasible. In 1986-87, we compared seed weight and germination of the main and ratoon crops of five varieties. Grain

Grain weight and germination of main and ratoon crop seeds. Pattambi, Kerala, India, 1986-87.

1000-grain Germination weight (g) (%)

Variety Main Ratoon Main Ratoon crop crop crop crop

BR51-315-4 23 19 96 97 BR52-96-3 25 22 96 98 Jaya 28 24 95 99 Pavizham 23 22 94 99 23332-2 20 21 92 98

LSD (P=0.05) 1 2

Performance of anther culture-derived lines. Coimbatore, India, 1986-87.

Days Plant Panicles Panicle 1000- Grain Production Entry to ht (no./ length grain yield (kg)

flowering (cm) hill) (cm) wt (g) (t/ha) per day

AC12 108 81 6.6 24.4 17.5 3.8 AC13 109 79 6.9 24.7 17.5 4.7 AC14 108 80 8.1 21.5 17.1 4.3 AC15 108 81 7.9 24.4 17.1 5.0 AC16 107 83 8.3 23.8 17.5 5.3 AC17 109 82 7.9 23.3 17.6 4.9 AC18 109 81 7.5 23.9 17.6 4.9 AC19 110 84 7.7 23.6 17.1 4.2 AC20 110 81 7.9 23.2 17.3 4.5 AC2 1 107 84 8.5 24.5 17.6 4.7 Ponni 122 121 6.1 26.9 14.8 7.0

6 ns ns 0.1 1.1 m+ 114 – – – – LSD (P=0.05)

– –

CV (%) 4 4 15.1 7.5 0.4 14.0

27.5 33.8 31.2 36.2 38.7 35.3 35.3 30.0 32.1 34.3 46.1

1,000-grain weight (see table). Panicle The lines derived from Ponni can be numbers and panicle lengths were not used as alternate genetic sources of shod statistically different. stature in rice breeding.

was dried to 12% moisture and 1,000- In spite of lower grain weights, ratoon grain weight estimated 1 mo after crop seeds germinated as well as main harvest. Germination was tested after 6- crop seeds (see table). mo storage.

Metroglyph analysis of some upland rice cultures

1986 were studied using indexes and

variability were divided into four group metroglyphs. Index values of range of

P. Gomathinayagam and S. Natarajan, using class intervals (see table). The two

Agricultural Research Station, Paramakudi most variable traits (plant height and 623707; and M. Subramanian and M. grain yield/ plant) are depicted on the X- Nagarajan, Agricultural College and and Y-axes; other characters are Research Institute, Madurai, Tamil Nadu, represented by rays on the glyph (rays India for the same trait have the same positiom

Morphological variations of 40 rice performance of a particular entry is entries tested at the upland rice site in denoted by its index score.

on each glyph) (see figure). The

Index scores for different traits of upland rice entries. Tamil Nadu, India.

Character Range of Score 1 Score 2 Score 4

means value < Score 3 value >

Days to maturity Tillers/plant Grains/panicle Root number Root length (cm) Root weight (g) Dry matter production 100-grain weight (g)

(g)

96.0 – 120.0 4.0 – 20

34.0 – 141 80.0 – 359 10.1 – 24.1

1.6 – 8.1 9.7 – 57.0 1.8 – 2.50

102 8

61 150

13.6

21.5 3.23

1.98

102.0 – 108 8 – 12

61 – 87 150 – 220

13.6 – 17.1 3.23 – 4.85

21.5 – 33.4 1.98 – 2.15

109 – 114 13 – 16 88 – 114

221 – 289 17.2 – 20.6 4.86 – 6.48

33.5 – 45.2 2.16 – 2.33

114 16

114 289

20.6

45.2 6.48

2.33

4 IRRN 13:4 (August 1988)

Scatter diagram of metroglyph analysis. Tamil Nadu, India.

1. IET7564 (lRAT8/N22) 2. IET7566 (M63-83/Cauvery) 3. IET7613 (M6383/Cauvery) 4. IET7614 (Rasi/Finegora) 5. IET8883 (RP143-4/Phalguna) 6. IET8887 (RP143-4/Phalguna) 7. IET8889 (RP1434/Phalguna) 8. IET9219 (Rasi/Finegora) 9. IET9221 (M63-83/IRAT8//N22)

10. IET9222 (M63-83/RP79-5) 11. IET9223 (M63-83/RP79-5) 12. IET9225 (Mettasanna/Rasi) 13. IET9367 (M63-83/Norin 21) 14. IET9576 (Phalguna/TKM6) 15. IET9809 (Ratna/Zagar) 16. IET9810 (IR36/Larbyol) 17. IET9813 (Phalguna/TKM6) 18. IET9814 (Phalguna/TKM6) 19. lET9815 (IR50/Phalguna) 20. IET9816 (IR50/Phalguna)

Entries

21. IET9817 (Phalguna/TKM6) 22. IET9818 (lR36/K47321) 23. IET9819 (lR36/K47321) 24. IET9822 (Rasi/Tellavadlu) 25. IET9823 (M63-83/Cauvery) 26. IET9824 (Rasi/Duccon) 27. IET9825 (Rasi/Finegora) 28. IET9826 (Rasi/Tellavadlu) 29. IET9827 (Rasi/Gajgour) 30. IET9828 (IRAT8/N22) 31. IET9829 (Rasi/Chithiraikar) 32. IET9830 (IET7614/ARC10372) 33. IET9831 (IET7564/IR50) 34. PM1381 (IR13564/ASD4) 35. Rasi (Chandikar/lR8) 36. TKM9 (TKM7/IR8)

38. TPS1 (IR8/Kattaisamba) 39. PMK1 (Co 25/ADT31) 40. Nootripathu (local)

37. IR50 (lR2153-14-1-6-2/IR28//IR36)

Score

1 2 3 4 Legend

Days to maturity Tillers/plant Grains/panicle Root number Root length Root weight Dry matter production 100-grain weight

The International Rice Research Newsletter invites contributions of concise summaries of significant current rice research for publication. Contributions should be limited to no more than 2 pages typed double-spaced, accompanied by no more than 2 figures, tables, or photographs. Contributions are reviewed by appropriate IRRI scientists and those accepted are subject to editing and abridgment to meet space limitations. Authors are identified by name and research organization. See inside front cover for more information about submissions.

Effect of waxy gene on rice yield components

Xu Yunbi and Shen Zongtan, Agronomy Department, Zhejiang Agricultural University, Hongzhou, China

We studied the effect of waxy gene on indica rice yield components in 1987, using three pairs of waxy and isogenic nonwaxy lines. (Waxy lines were bred from crosses between their nonwaxy lines and IR29 by Shaoxing Institute of Agricultural Sciences, Zhejiang.)

Seedlings were transplanted at 10- × 18-cm spacing in 1- × 2-m plots, in a split-plot design. Ten plants were sampled from each plot to measure yield components, grain, and rough rice.

Differences in 1,000-grain weight between waxy and nonwaxy lines might be attributed to grain size (see table). Waxy lines have smaller kernels and lower specific gravity.

The potential sink of photosynthates in waxy lines was comparable to that in nonwaxy lines because both had large grains and high percentage of fertile spikelets. The gap between the floral glume and kernel in waxy grain was larger.

Both the lower percentage of rough rice (due to the higher 1,000-hull wt) and the lower specific gravity of grains in waxy lines might make their rough rice yield much lower than expected.

IRRN 13:4 (August 1988) 5

Characteristics of waxy and nonwaxy isogenic lines. a Hangzhou, China, 1987.

Guangluai 4 Yuanfengzao Zhenzhu 19 Character

Waxy Nonwaxy Difference Waxy Nonwaxy Difference Waxy Nonwaxy Difference

Plant ht (cm) Rough rice

1000-grain wt (g) Grain length (mm) Specific gravity of

Percentage rough rice

Length (mm) Width (mm) Thickness (mm) Size (mm 3 ) 1000-grain wt (g)

grain (g/ml)

Brown rice

76.10

21.40 6.97 0.99

78.83

5.24 2.73 1.94

27.81 17.72

75.88

23.08 6.80 1.10

80.15

5.42 2.89 2.03

31.83 20.34

0.22

–1.68** 0.17*

–0.11**

–1.32**

–0.18* –0.16* –0.09* –4.02** –2.62**

80.45

18.05 6.19 1.02

79.10

5.13 2.35 1.92

23.10 15.64

78.08

19.60 6.70 1.10

80.44

5.36 2.57 1.98

26.98 17.41

2.37*

–1.55** 0.09

–0.08**

–1.34*

–0.23** –0.22** –0.06* –3.88** –1.77**

93.28

28.30 8.70 1.04

80.74

6.83 2.62 2.06

36.80 23.86

91.43 1.85

31.35 –3.05** 8.7 1 1.12

–0.01 –0.08**

82.47 –1.73**

7.13 –0.30** 2.84 –0.22** 2.11 –0.05**

42.64 –5.84** 27.50 –3.64**

a * and ** = significance at the 5% and 1% levels.

Grain quality and nutritional value

Rice varietal differences in Head rice recovery of 36 varieties and lines. a Maros, South Sulawesi, Indonesia, 1985-86 dry season.

number of brokens ~~

T. M. Lando, Agricultural Engineering Department, Maros Research Institute for Food Crops, P.O. Box 173, Ujung Pandang, South Sulawesi, Indonesia

Rice varietal differences in grain form, size, and weight affect percentage of brokens after milling. That determines milling recovery, percentage of head rice, and price.

varieties and lines, then hulled 140-g grain samples with a small Satake rubber roll rice hulling machine (THU 35 A). The experiment design was completely randomized with four replications.

Of the varieties tested, 13 had more than 80% head rice (see table). Among them are four lines not yet released—

30-NG-4-2, and IR4427-5-6-3. IR56 had the lowest head rice percentage.

We measured moisture content of 36

M61b-28-3-5, IR4427-85-2-1, B4180F-

For information on ordering IRRI publications, write Communication and Publications Dept., Div. R, IRRI, P.O. Box 933, Manila, Philippines.


Variety Rough rice

moisture content (%)

Brown rice (%)

Head rice Brokens (%) (%)

M61b-28-3-5 13.5 91.4 a 6.7 a Barito 13.3 86.6 a 7.7 a IR26 13.3 87.5 a 8.1 b

Semeru 12.3 77.4 ab 10.2 b Cisadane 13.5 88.0 a 10.3 b Kelara 15.1 79.8 ab 10.4 b Bogowonto 14.2 84.7 a 11.7 b IR46 13.5 85.2 a 12.5 bc Batang Agam 14.3 84.2 a 12.6 bc Krueng Aceh 13.2 82.4 a 12.6 bc Sadang 13.8 84.5 a 12.7 bc

13.8 c 11.9 77.6 ab 14.4 c

Cipunegara 14.2 82.5 a 14.4 c M12C-34-3 14.2 78.4 ab 15.7 c IR4427-5-6-3 12.8 80.3 a 16.2 c BR-5 1-282-8 14.3 79.1 ab 17.4 c

IR4427-85-2-1 13.5 87.3 a 8.5 b

B4180F-30-NG-4-2 13.6 83.4 a BR319-11-HR12

Citarum 12.4 77.3 b 17.8 c IR36 12.9 77.7 ab 17.7 c

Cikapundung 14.6 77.7 ab 19.7 cd GH2 18 14.3 76.2 b 21.0 d

Cimandiri 14.9 72.6 b 21.4 d B5322b-Pn-1-MS-1-KP-1 14.9 75.7 b 22.2 d IR5 0 12.5 72.6 b 23.1 d IR30 11.6 71.2 b 23.3 d IR22082-41-2 14.1 71.6 b 24.9 d IR58 13.9 70.3 b 26.5 de IR28 10.8 68.0 c 26.9 e IR54 12.8 66.2 c 27.9 e IR60 12.7 66.9 b 27.9 e IR5 2 11.9 61.9 c 33.0 e

IR56 11.0 53.1 c 44.0 f

a In a column, means followed by the same letter are not significantly different at the 5% level by DMRT.

BR-IRGA-409 13.9 77.6 ab 18.1 c

IR4425-85-2-1 14.1 87.3 a 21.2 d

B40706-NG-2 12.7 61.0 c 35.6 ef

Disease resistance suspension at 21 d after transplanting (DT) for kresek and at 45 DT for leaf blight and scored at 30 and 14 d after inoculation. For screening for SR

infected plot and disease incidence recorded at maturity.

Resistance of rice breeding resistance, entries were planted in an

lines to bacterial blight (BB) and stem rot (SR) The leaf blight and kresek phases

D. V. S. Panwar, M. P. Bansal, H. Chand, and M. R. Naidu, Haryana Agricultural University (HAU), Rice Research Station (RRS), Kaul 132021, Haryana, India

We screened 91 genotypes with short to medium durations for reaction to BB Xanthomonas campestris pv. oryzae (Ishiyama) Dye (leaf blight and kresek phase) and SR Sclerotium oryzae Cattaneo during 1984 wet season.

long rows, at 20- × 15-cm spacing. Plants were clip-inoculated with BB

Each entry was planted in two 5-m-

differed. Only 10 lines showed resistance to the kresek stage, but 30 showed resistance to the leaf blight phase.

and DV85 had resistance to both kresek and leaf blight phases (see table). Only HKR120 showed resistance to both phases of BB and to SR. HAUl18-104, HAU118-154, HAUll8-726, HAU83- 164, RP2151-21-1, and TKM6 showed resistance to two problems and moderate resistance to one. These lines (except TKM6 and DV85) also have desirable agronomic traits.

HAU1 18-104, HKR120, CR294-548,

Reaction of rice lines to SR, and the kresek and leaf blight phases of BB in the field at HAU, RRS, Haryana, India, 1984 wet season.

Days to Reaction a to

heading Kresek Leaf blight Stem rot Entry Parentage 50%

HAU118-104

HAUl18-106

HAU118-111

HAUl18-154

HAUll8-187

HAUll8-726

HAU118-788

HKRl20 HKRl22 HAU83-38 HAU83-164 HAU83-222 RP2151-21-1 RP2151-224-4 RP2151-173-1-8 IET4 14 1 IR54

CR3 19-644 CR294-548 Govind IR9784-142-1-3 IR13420-6-3-3 TKM6 DV85

Nam Sagui 19/IR4215-301-2-2//

Nam Sagui 19/IR4215-301-2-2//

Nam Sagui 19/IR4215-301-2-2//

Nam Sagui 19/IR4215-301-2-2//

Nam Sagui-19/IR4215-301-2-2//

Nam Sagui 19/IR4215-301-2-2//

Nam Sagui 19/IR4215-301-2-2//

IR5853-162-1-2

IR5853-162-1-2

IR5853-162-1-2

IR5853-162-1-2

IR5853-162-1-2

IR5853-162-1-2

IR5853-162-1-2 Ptb 33/4* IR3403-267-1 Ptb 33/4* IR3403-267-1 SFCIII/Basmati 370 SFCIII/Basmati 370 SFCIII/Basmati 370 IET4141/CR98-7216 IET4141/CR98-7216 IET4141/CR98-7216 IR8/BJ143//IR22 Nam Sagui 19/IR2071-88// IR2061-214-3-6

–

IR20/IR24 –

IR1632-93-2-2/IR5534 IR2863-38-1/2* IR36

– –

109 R

104 MS

106 R

106 MR

107 MR

104 R

108 MR

111 R 115 MR 106 MS 122 MR 119 MR 110 MR 122 MR 110 MR 112 MS 121 MR

110 MR 108 R

86 MR 101 MS 109 MR 115 MR

92 R

R

R

MR

R

R

MR

R

R R R R R R MR R R R

R R R R R R R

MR

R

MR

R

MR

R

MR

R MR MR R MR R R MR R MR

MR MS MR MR MR R S

a R = resistant (score of 3 or lower), MR = moderately resistant (5), MS = moderately susceptible (7), and S = susceptible.

Field reaction of IR varieties to rice tungro (RTV)- associated viruses

A. Muis, M. Sudjak S, A. Bastian, S. Sama, and A. Hasanuddin, Maros Research Institute for Food Crops, P. O. Box 173, Ujung Pandang, South Sulawesi, Indonesia; and R. C. Cabunagan and H. Hibino, IRRI

IR varieties planted in monthly planting trials in the experimental field at Maros and in the RTV nursery at Lanrang substation, South Sulawesi, were used to assess incidence of rice tungro bacilliform virus (RTBV) and rice tungro spherical virus (RTSV) Aug-Oct 1986. Leaf samples were collected from 10 plants of each variety at 30 and at 45 d after transplanting (DT) and indexed by latex test.

RTBV and RTSV incidence varied with month of planting (Table 1). Regardless of variety, virus incidence was higher in plots planted the last wk

Table 1. RTBV and RTSV incidence at 45 DT in 10 varieties planted on 1 Aug, 30 Aug, and 1 Oct, 1986, Maros, South Sulawesi, Indonesia.

Plants a (%) with

RTBV+RTSV RTBV Planting date Variety

1 Aug 1986 IR26 0 10 IR30 0 30 IR42 30 0 IR54 10 20 IR58 0 0 IR60 0 0 IR62 0 0 IR64 0 0 TN1 70 0

30 Aug IR26 10 50 IR30 20 40 IR42 70 0 IR54 70 0 IR58 20 0 IR60 10 0 IR62 10 0 IR64 20 0 TN1 100 0

1 Oct IR26 0 40 IR30 30 10 IR42 80 10 IR54 30 10 IR5 8 0 10 IR6 0 0 0 IR62 0 0 IR64 10 10 TN1 100 0

a No variety showed RTSV infection only.


of Aug. IR58, IR60, IR62, and IR64 had low or no RTBV + RTSV infection.

In the Lanrang RTV nursery, RTV incidence was high even at 30 DT (Table 2). IR50, IR52, IR54, IR58, and IR60 had high infection with RTBV + RTSV.

These results indicate that GLH- resistant varieties IR50, IR52, IR54, IR56, IR58, IR60, IR62, and IR64 can be attacked by RTV in South Sulawesi. Moderately resistant IR20 and IR26 were infected with RTBV only.

Table 2. RTV incidence based on symptoms, and RTBV and RTSV incidence based on the latex test at 30 DT in 14 varieties. Lanrang, South Sulawesi, Indonesia, 1986.

RTV Plant a (%) with Variety incidence

(%) RTBV+RTSV RTBV

IR20 20 0 30 IR26 30 0 40 IR30 25 10 10 IR36 60 40 0 IR40 40 40 10 IR42 65 40 0 IR50 50 50 0 IR52 45 30 20 IR54 45 30 20 IR56 25 10 20 IR5 8 30 30 10 IR60 30 40 0 Kelara 5 0 10 TN1 85 70 0

a No variety showed RTSV infection only.

Reaction of International Rice Bacterial Blight Nursery (IRBBN) cultures to an Aduthurai, India, bacterial blight (BB) pathotype

A. Chandrasekaran, R. Marimuthu, V. Sivasubramanian, and P. Vidhyasekaran, Tamil Nadu Rice Research Institute (TRRI), Aduthurai 612101, India

In Sep 1987 we screened IRBBN cultures against a pathotype of Xanthomonas campestris pv. oryzae we had isolated. The Aduthurai pathotype drew reactions different from those to other Indian isolates (Table 1).

Plants were inoculated by clipping leaf tips with scissors dipped in

Table 1. Reaction of rice varieties to local BB isolates in India.

Reaction of variety

IR20 TKM6 Cas 209 Kogyoku DV85 IET4141 BJ1

Aduthurai S S S S R R R Cuttack R R R R – S S Hyderabad R R Haryana R R Pantnagar S S S S S S S Delhi S S S S S S S Punjab R R Pusa R R S Maruteru (Andhra) S Dholi (Assam) S Kajat (Madhya Pradesh) S

Isolate origin

Table 2. Reaction of rice varieties to the Aduthurai BB pathotype. Aduthurai, India, Sep 1987.

Culture Parentage Origin Disease score a

RP2151-173-1-8 RP2151-40-1 Kachamota DV85 RP2151-21-22 AC19-1-1 IR33380-60-1-2

Kuntlam Nigeria 5 IR20 BR161-26-58 BR285-5-6-6 Camor C721313 IR13146-45-2 IR24632-145-2-2

IR29295-70-1-1 IR29341-85-3-1 IR33356-22-3-1 IR33360-5-3-2

Koiadigha Nancay P.A. RTN90-4

IR8 IR1545-339-2-2

BR315-12-1-4 BR319-1-HR 28 B40750-PN-13-1 C712311 C731051 C731067 IRAT109 IR11288-8-8-445 IR33355-39-1-1 IR5853-213-6-1

Kalimekri-77-5 Kogyoku RP1575-143-823-1 UPR79-80 TN1

IET4141/CR98-7216 IET4141/CR98-7216

– –

IET4141/CR98-7216

IR52/IR13240-39-3// IR9224-117-2-3

–

Peta/DGWG

Peta 3/TN1/TKM6 Chandina/IR425-1-1-3 Biplab/Chandina

C651042/Milyang 23//C682032

–

–

BG90-2/IR34//IR46 IR5657-33-2/ IR4707-106-3-2//IR48 IR36/Mashuri IR54/IR46 IR52/IR48//IRS2 IR52/IR5657-33-2// IR9224-117-2-3-3

–

SML 81-B-25/R68 –

IR24/DZ192 Peta/DGWG IR5 (J)/Biplab IR5 (D) Biplab

C681065/TCS254 C701040/C701027

IRAT13/IRAT10 IR36/Leb Mue Nahng III

Nam Sagui 19/

E2484 B/2-PN-29-2/IR36

C681030/IR13429-57-1

IR52/IR46/IR6115-1-1-1

IR2071-88//IR2061-214-3-6 –

Shirosenbon/Shobei TNl/Luangu

DGWG/Tsai-Yuan-Chan –

India India Bangladesh Bangladesh India Bangladesh IRRI

Indonesia Sri Lanka IRRI Bangladesh Bangladesh Indonesia Taiwan IRRI IRRI

IRRI IRRI IRRI IRRI

Bangladesh Argentina India IRRI IRRI Bangladesh Bangladesh Indonesia Taiwan Taiwan Taiwan Ivory Coast IRRI/Thailand IRRI IRRI

Japan Bangladesh India India Taiwan

3 3 3 3 5 5 5

7 7 7 7 7 7 7 7 7

7 7 7 7

7 7 7 9 9 9 9 9 9 9 9 9 9 9 9

9 9 9 9 9

a By SES.


inoculum containing about l0 8 cells/ml. Disease intensity was scored after 14 d, using the Standard evaluation system for rice (SES) scale.

Kachamota, and DV85 showed resistance to the Aduthurai pathotype (Table 2).

Only RP2151-173-1-8, RP2151-40-1,

Field and screenhouse evaluation for resistance to rice tungro (RTV) G. Bhaktavatsalam, S. K. Mohanty, and S. K. Singh, Plant Pathology Division, Central Rice Research Institute (CRRI), Cuttack 753006, India

We evaluated high-yielding rice varieties and lines for field tolerance to RTV in the 1985 wet season. Infection was scored 30 d after transplanting and field tolerance was scored after flowering.

Varieties and lines scoring 1 to 3 were tested in the screenhouse in the 1986 wet season, with 20 seedlings/variety exposed to either 1 or 5 RTV- viruliferous leafhoppers Nephotettix virescens per seedling. Symptoms were scored and seedlings tested for presence of the bacilliform (RTBV) and spherical (RTSV) viruses by latex serological test. Infection rate and plant height and tiller number reduction were scored visually.

Virippu and Ptb 18 scored 1 in the field but had high infection in the screenhouse (see table). Some varieties showing field tolerance had high infection in the screenhouse. Reduction in height and tiller number was less in varieties with field tolerance score 1 than in varieties with score 3.

Infection with both RTBV and RTSV was low in these varieties. Some had RTBV alone. RTSV infection alone was low (0-10%). Ambemohar 59, BJ1, and Gopalbhog were not infected with either virus. Infection and reduction in height and tiller number were higher in plants inoculated at 5 hoppers/ seedling.

Although Utkalprabha and Sabari had high infection in the field, by time of flowering they showed tolerance scores of 2 and 3.

RTV incidence in rice varieties in the field (1985 wet season) and in a screenhouse test (1986 wet season). Cuttack, India.

Field Screenhouse b

Symptoms Tolerance RTBV+RTSV RTBV RTSV (%) score a (%) (%) (%)

Popular Indian varieties Ambemohar 59 0 1 0 0 0 Basmati 370 2 1 0 10 0 Krishnabhog 3 1 0 10 0 Mudgo 0 1 0 10 0 Ptb 18 0 1 0 60 0 Tulsimanjari 2 1 0 10 0 Type 90 2 1 0 20 0 Virippu 6 1 0 30 10 Amaravathi 0 2 10 30 0 BJ1 0 2 0 0 0 Gopalbhog 4 2 0 0 0 Pokkali 7 2 10 30 0 Utkalprabha 25 2 20 50 0 Vytilla 2 2 2 10 30 0 White Luchai 5 2 10 20 0 Asha 18 3 10 0 0 Aswathi 3 3 10 20 0 Daya 15 3 10 20 10 Ratna 8 3 0 20 0 Sabari 51 3 10 10 0 TN1 (check) 100 9 80 0 0 CRRI breeding lines CR146-7001 2 1 0 10 0 CR146-7004 15 2 10 20 0 CR260-131-5-713 12 2 10 30 0 CR316-639 6 2 0 20 0 CR365-134 9 2 10 20 0 CR319-644 6 3 10 0 0 CR260-136-321 7 3 10 20 0

than 20% did not flower; 9 = plants show orange yellow color, severe stunting, and no flowering. a 1 = no visible symptoms; 2 = plants are green, slightly stunted, less than 10% did not flower; 3 = less

b Mass inoculation at 5 leafhoppers/seedling. All varieties except two had 0 RTSV: Virippu and Daya had 10% RTSV. LSD for the screenhouse symptoms was 17.83 (0.05) and 24.07 (0.01).

Reactions of Mahsuri and Sona Mahsuri to blast (Bl) State. But it is highly susceptible to neck

Bl. We are looking for a variety with

Y. Rathaiah, Regional Agricultural Research Station, Titabar 785630, Jorhat District; and A. Bhattacharyya and U. N. Saikia, Mycology Research Unit, Assam Agricultural University, Jorhat 785013, Assam, India

Mahsuri rice covers a substantial area during the Jul-Dec season in Assam

Mahsuri-type grain and resistance to neck Bl.

the cross Sona/ Mahsuri (released in Karnataka State as Mandya Vijaya), with panicle traits similar to Mahsuri, is moderately resistant to leaf Bl. We compared leaf and neck Bl reactions of Sona Mahsuri and Mahsuri.

Sona Mahsuri (KMS5914-4-6) from

Table 1. Leaf and neck Bl reactions a of Mahsuri and Sona Mahsuri. Assam, India.

Leaf Bl Neck Bl Variety

Score Reaction % Score Reaction

Sona Mahsuri 4 MR 18.1 5 MR Mahsuri 7 S 97.4 9 HS Pusa 2-21, susceptible check 8 S 98.5 9 HS a MR = moderately resistant, S = susceptible, HS = highly susceptible.


Table 2. Yields of Mahsuri and Sona Mahsuri. Assam, India.

Days to Grain yield Variety 50% (kg/l.6 m2

flowering plot)

Mahsuri 98 1 Sona Mahsuri 92 1

Two rows of 28 hills of each variety, Sona Mahsuri was moderately divided by one row of susceptible check resistant to both neck Bl and leaf Bl Pusa 2-21, were grown. Leaf Bl was (Table 1). Mahsuri was susceptible to scored by The standard evaluation leaf B1 and highly susceptible to neck Bl system for rice Neck Bl was recorded as Grain yields were on a par, but Sona percent affected panicles on 10 random Mahsuri matured 1 wk earlier than hills. Yield was measured at a B1-free Mahsuri (Table 2). site.

Screening new rice selections for reaction to major diseases

H. E. Shashidhar, S. Hittalmani, Sheshadri, H. L. Vasant Kumar, and G. Shivashankar, University of Agricultural Sciences, GKVK, Bangalore, India

We evaluated 18 stabilized lines from the rice improvement program and 18 released cultivars for leaf blast (Bl), neck Bl, sheath rot (ShR), and grain

discoloration (Gld) at the Agricultural Research Station, Ponnampet, (hot spot for B1 disease in rice) during 1986 wet season.

Selections from Pusa l50/IR36 and Pusa l50/IM 1 were resistant to leaf B1 (see table). Neck B1 infection was lowest in IR20, Karuna, and Jaya.

Selections from Jaya/Mahsuri were free of ShR infection. Maximum infection was in Pragathi and selections of Jaya/Type 3.

Incidence of leaf B1, neck B1, ShR, and Gld. Ponnampet, Karnataka, India, 1986 wet season.

Jaya, IR20, and Jaya/ Mahsuri derivatives had the most Gld. Mahsuri, Intan Gowri, and Prakash had none.

Karuna and selections from Pusa 150/IM 1 showed combined tolerance for all four biotic stresses.

For instructions on preparation of brief reports of rice research to submit for

publication in IRRN, see the inside front cover of this issue.

Leaf Entry blast a

Neck B1 ShR incidence infection Gld

(% affected) (%) (%)

Pusa 150/IR36

Karuna Mahsuri Intan Gowri Jaya Intan mutant 1 IR20 Pusa 150/Tellahamsa Jaya/Type 3 Mandya Vijaya Puspha IET7031/Mangala Pusa 150/Sona Mashuri Nandi Mahsuri/IR36 Prakash Rasi Jaya/Basmati

ES18 Mandya Vani

Jaya/Mahsuri Jaya/IET7031 Madhu Pragathi Naga Mangala IET7031/Tellahamsa Sharavathi Jaya/ Halubbulu Pusa 150/Basmati Intan Tellahamsa Mahsuri/Doddy Karikagga/Halybbulu Arkavathi

Pusa 150/IM-1 0 0 0 1 1 1 1 2 2 2 2 2 3 3 3 3 4 4 4 5 5 5 5 6 6 6 7 7 7 7 7 9 9 9 9 9

44.1 22.2 10.2 46.8 52.9 14.0

7.4 29.6 70.2

17.0 74.1 81.9 87.0 77.6 33.7

55.8 45.1

68.8

41.9 76.2

60.9 72.1

10.2 b

3.3 5.0 23.0 1.0

6.8 1.0 14.5 0.0 23.5 0.0 19.8 25.0

9.3 25.0 4.3 5.0

36.2 5.0

13.2 1.0 6.9 11.0 4.6 1.0 5.7 1.0

22.4 5.0 18.6 0.0

1.9 5.0 31.4 10.0

0.0 20.0

Wiped out by neck Bl

Wiped out by Bl

Wiped out by Bl

Wiped out by Bl

Wiped out by Bl Wiped out by Bl

39.6 10.0 20.6 1.0

23.2 5.0 27.9 1.0

Wiped out by Bl

Wiped out by Bl Wiped out by Bl

Wiped out by Bl Wiped out by Bl Wiped out by Bl Wiped out by Bl

2.6 b 2.0 b

a By the Standard evaluation system for rice scale 0-9. b From side tillers.

10 IRRN 13:4 (August 1988)

Bacterial blight (BB) development in rice varieties and screening tests

B. N. Mahto and R. N. Singh, N. D. University of Agriculture and Technology, P.O. Dabha Semar, District Faizabad 224133, U.P., India

Genetic resistance appears to be the only feasible method of managing BB in the tropics and subtropics. In most screening tests, leaves are clip-inoculated with the local isolate of the pathogen at maximum tillering stage, with disease rated 15 d after inoculation (DAI). Total uniformity in the stage of plant growth, vigor, microclimate, amount of inoculum applied, and the mechanism of disease development in test varieties is difficult to achieve.

We evaluated inoculated plants against a wider spectrum of environmental conditions by rating disease in test varieties twice—15 and 35 DAI.

Some varieties expressed the maximum measurable response to Xanthomonas campestris pv. oryzae

Disease reactions 15 and 35 DAI. Faizabad District, U.P., India.

Disease-score a

15 DAI 35 DAI

Type of Varieties reaction b (no.) Representative test varieties

Anjani III, Bishunbhog, Damodar, IR20, 1 1 R 7

Chinidardi, Dehradun (Mota), Dhurigabha, Gallor, 1 3 MR (SB) 11

Katri, Loungchoor, Rambhog, Saraya, Sita, 3 3 MR 10

Chameli 1 5 MS (VSB) 1 Beni, Benideoria, Gaurea, Mutmuri, Pankhali, 3 5 MS (SB) 24

Adamchini, Amgandh, Badshah Pasand, 5 5 MS 29

Agwar, Bilaspur, Delha, Dadhaha, Sonachoor, 3 7 S (VSB) 6

Ashahniya, Basahwa, Dudaha, Jaisuria, 5 7 S (SB) 13

Bajri, Bakki, Karhan, Kotabasmati, Mirchbooti, 7 7 S 13

Champa (C), Kalamdan, Mutra, Sukhwan, 5 9 HS (VSB) 9

Gheebhat, Kalakand, Karnya, Kashi P.D., 7 9 HS (SB) 11

Anand, Anjana, Bindibali, Bindikali, Gajgaur, TN1 9 9 HS 30

a By the Standard evaluation system for rice (1980). b R = resistant, MR = moderately resistant, MS =

slow blighting. moderately susceptible, S = susceptible, HS = highly susceptible, SB = slow blighting, VSB = very

Randhuri, Zeerabatti

Gajraj, Kala Namak

Surajpankhi 374

Shyamzsera

Bhagalpuri, Ramjas

FRG10

Lalkibhadai, Sumokhan

Motibadam

Tinpakhiya, Agtahwa (FD)

Madhukar, Ramkajra

infection within 15 DAI; others took more time (see table).

The results indicate the limitations of recording observations only at 15 DAI. It is possible to divide reaction groups into normal blighting, slow blighting, and very slow blighting varieties.

The International Azolla Newsletter is published for researchers in the development and application of azolla in rice production. Its content focuses on discussions of current issues; it does not publish research reports. For more information, write Dr. I. Watanabe, Azolla Newsletter editor, IRRI, P. O. Box 933, Manila, Philippines.

Individuals, organizations, and media are invited to quote or reprint articles or excerpts from articles in the IRRN.

Insect resistance

Incorporation of brown planthopper (BPH) resistance genes from indica into japonica rice

Yang Tibin, Gu Fulin, Shi Suoshun, and Gu Zhengyuan, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu 210014, China

None of the 8,200 japonica varieties or lines we screened in 1976-82 were resistant to BPH. Resistance genes can only be found in the tall traditional indica varieties of South Asia. We transferred BPH resistance genes from indica to two japonica lines (80047 and 80079) in 1980. Using those lines as resistance sources, several promising japonica lines resistant to BPH have been developed (see table). • 864 derived from Yan Keng

2//791943/80047 yields 8 t/ha, 10% more than widely grown Yan Keng 2 and is suitable for single and double cropping in the Chang Jiang River

Yield performance and insect resistance of promising japonica lines. Jiangsu, China, 1987.

Plant Panicles Grains Sterility 1000-grain Yield Resistance

(g) (t/ha) BPH BB Bl Line Duration height (no./ (no./

(d) (cm) plant) panicle) (%) weight

8 64 147 100-105 9 120 26.0 8.0 MR R R 870064 155

8 90-95 9 146 14.2 25.3 7.9 R R R

850041 150 95-100 8 116 24.0 23.0 7.0 R R MR

basin. It is resistant to bacterial blight (BB) and moderately resistant to BPH and blast (Bl). Its grain quality is acceptable to consumers.

2//791943/80047///Non Ken 57/IR26) yields 8 t/ ha and is suitable for the Tai-hu Lake basin and the

• 870664 (Yan Keng

Chang Jiang River basin. It is resistant to BPH, Bl, and BB.

has large panicles, but unsatisfactory lodging resistance. Average yields are 7 t/ha. It is highly resistant to BPH and BB, but susceptible to sheath blight.

• 850041 derived from 791943/80047

Screening resistance

rice seedlings for to leaffolder (LF)

R. Rajendran, Centre for Plant Protection Studies, Tamil Nadu Agricultural University (TNAU), Coimbatore 641003, India

We screened 26 accessions from the All India Coordinated Rice Improvement Project at the seedling stage for

resistance to LF Cnaphalocrocis medinalis in the 1987 wet season.

apart in 50- × 40- × 10-cm wooden seedboxes. Six rows of each accession were planted across the width of the seedbox, for 3 plants/ hill, 5 hills/row. One row of susceptible check TN1 and one row of resistant check Ptb 33 were sown at random in each seedbox.

Pregerminated seeds were sown 6 cm

IRRN 13:4 (August 1988) 11

Seedboxes were transferred to iron trays (60 × 40 × 15 cm) filled with 5 cm water 7 d after seeding (DAS). The boxes were covered with nylon net cages 20 DAS and 10 moth pairs/cage released in each cage. (A cotton swab soaked in 1% sugar solution was hung inside the cage as food for the moths.)

LF damage was assessed 15 d after release of moths.

microplots (2 × 2 m). TNAULFR831324, 832042, 842718, 842735, and 842745 exhibited good resistance in the greenhouse and in the microplots (see table).

Moths were allowed to oviposit 3-4 d.

The same accessions were screened in

Field incidence of and host resistance to Angoumois grain moth (AGM)

K. N. Ragumoorthy and K. Gunathilagaraj, Agricultural Entomology Department, Agricultural College and Research Institute, Tamil Nadu Agricultural University, Madurai 625104, India

We surveyed field incidence of AGM Sitotroga cerealella O. on rice in the field at the Agricultural College in Madurai and the Tamil Nadu Rice Research Institute in Aduthurai. Seed samples of 100 g for each variety were collected in polythepe bags and adult moth emergence monitored for 6 wk.

AGM emerged from 124 of 2 13 samples at Madurai and from 59 of 151 samples at Aduthurai. Incidence was highest in IR and CO varieties; IR20, IR50, IR54, IR64, CO 25, CO 31, CO 37, CO 42, CO 43, CO 44, ACMl1, ACM12, IET7254, ADT36, AD85003, NLR9672, Ponni, TNAU801790, TNAU831293, TNAU831520, and TNAU831521 showed field infestation in both places.

We evaluated 38 CO varieties for resistance on the basis of number of moths emerging, percentage infested grains, weight loss, and weight of adult moths; 15 were resistant.

Resistant CO 1, CO 27, and CO 32; moderately resistant CO 40; moderately susceptible CO 42; and highly

12 IRRN 13:4 (August 1988)

Reaction of rice seedlings to LF. Coimbatore, India, 1987 wet season.

Damage rating a

Greenhouse Microplot Accession Cross

TNAULFR831324 Bhavani/IR4707-106-3-2 3 3 TNAULFR832042 Bhavani/ARC10550 TNAULFR842718

3 Bhavani/ARC10550

5

TNAULFR842735 3 3

Bhavani/IR4707-106-3-2 TNAULFR842745

3 5 Bhavani/IR4707-106-3-2 3

Balam (donor) 5

3 Rasi/Chittaraikar

5 5 5

Rasi/Chittaraikar 5 5 Rasi/Chittaraikar

ARC11281 (donor) 5 5 5 5

Choorapundy (donor) – 5 5 TN1 (susceptible check) DGWG/Tsai-Yuan-Chan 9 9 Ptb 33 (resistant check) – 3 3

– RP2430-350-54 RP2430-361-3 RP2430-372-75

–

a By the Standard evaluation system for rice.

Physical and biochemical characters of rices resistant to Angoumois grain moth in India.

Physical characters Biochemical factors Husk a

( cm) Variety thickness Grain Length: 100-grain Silica, Total Total

hardness a breadth weight c content d protein d amylose d

(alkali value) ratio b (g) (%) (%) (%)

CO 32 0.031 2 4.0 CO 21 0.037 2

1.8 18.9 5.9 23.9

CO 1 3.5 2.0 19.1

0.032 9.8

1 28.9

3.1 CO 40 0.027

2.1 17.9 9.2 24.5 4 2.0 2.3 16.8 8.2 20.7

CO 42 0.019 3 2.7 2.1 16.8 6.5 CO 43 0.017 4

19.9 2.1

CO 44 0.014 1.9 15.1 6.5

5 19.4

1.9 1.9 15.1 7.6 21.9

a Mean of 10 observations. b Mean of 15 observations. c Mean of 3 replications. d Mean of 2 replications.

susceptible CO 43 and CO 44 were protein, and amylose content were selected to study factors conferring analyzed. In general, resistant varieties resistance. had thick husk, low alkali value, coarse

Husk thickness, grain hardness (alkali grain, higher 100-grain weight, and high value), length-breadth ratio (grain silica, total protein, and total amylose fineness), 100-grain weight, and silica, content (see table).

Excess water tolerance

Breeding for submergence in mid-Jun. We studied FR13A,

tolerance FR43B, and CN540, their two hybrids, and susceptible check IR20 for

S. Mallik, C. R. Lakhe, N. K. Mitra, and B. submergence tolerance and recovery. K. Mandal, Rice Research Station, Initial height and leaf and tiller Chinsurah 712102, West Bengal, India number of 10-, 30-, and 40-d-old

seedlings were recorded, and seedlings In eastern India, rice seedlings are likely were submerged in either 30 or 60 cm to be submerged 30-40 d after deep water. Survival percentage, height transplanting when the monsoon breaks and leaf number were taken, and

Survival and recovery of seedlings of different ages at 2 water depths. West Bengal, India.

seedlings left for 10 d more under saturated moisture to estimate recovery capacity.

initial height and leaf and tiller number. FR13A and FR43B were the tallest and had the most leaves in all age groups. In general, IR20 scored lowest for all characters, except it had the most tillers at 40 d old.

Highest survival of 10-d-old seedlings was in FR13A and CN716 at both flooding depths, followed by FR43B and CN717 (see figure). No IR20 plants survived the 60-cm water depth. All older seedlings of CN540 and FR43B survived.

recovery of younger seedlings at both water depths; 40-d-old seedlings surpassed both parents in 60 cm water. FR43B had good overall recovery at all seedling ages. No 10 d IR20 seedlings recovered; recovery otherwise increased gradually with seedling age.

Most varieties had higher elongation rates at 30 cm than at 60 cm water depth (see table). Ten-day-old CN540 seedlings had the highest elongation rate, FR43B elongated most in 30 cm and FR13A in 60 cm.

low elongation rate in older seedlings

Varieties differed significantly in

Only CN716 showed complete

High initial height was correlated with

Elongation rate during submergence of 6 varieties at 10, 30, and 40 d old. West Bengal, India.

Elongation per d (%)

Variety 10 d old 30 d old 40 d old

30 cm 60 cm 30 cm 60 cm 30 cm 60 cm

CN540 (Suresh) 13.1 1.8 4.1 8.9 6.2 7.4 FR13A 2.6 3.1 5.0 5.6 1.4 5.2 FR43B 13.1 –1.4 2.8 1.9 5.9 1.4 CN716 (FR13A/CN540) 4.9 0.2 6.3 6.3 12.0 6.4 CN717 (FR43B/CN540) 2.5 1.5 4.6 3.0 5.1 6.6 IR20 (susceptible check) 10.1 dead 1.5 2.4 –4.9 –2.2

(–0.60 and –0.70 at 30 cm, and –0.81 and –0.73 at 60 cm water) but not with Adverse temperature survival. Initial leaf number was positively correlated with survival only tolerance in 40-d-old seedlings at 60 cm water depth (0.60).

The resistant varieties can be divided into two groups: FR13A type and CN540 or FR43B type. FR13A type was more resistant at the heterotrophic stage (seedling surviving on endosperm), CN540 type was more resistant at the autotrophic stage (seedling producing its food).

Screening at both seedling stages could help identify resistance donors. Development of bridge parents such as CN716 (FR13A/CN540) that combine both types of resistance should lead to the production of genotypes with better flood tolerance.

Screening criterion for cold tolerance at the seedling stage

Xu Yunbi and Shen Zongtan, Agronomy Department, Zhejiang Agricultural University, Hangzhou, China

In the Yangtze valley in China, the first crop indica rice is sown in early Apr and transplanted in early May. Seedlings die when temperatures are abnormally low (6-10 °C for 5 d or longer). We investigated a screening criterion for cold tolerance at the seedling stage.

IRRN 13:4 (August 1988) 13

Table 1. Response of 5 rice varieties to low temperature (10/6 °C day/night) for 3, 7, 9 d. Hangzhou, China.

Response

3d 7d 9d Variety

IR26 Tip of leaves All leaves Plant dead rolled into tubes

or withered

Erjiufeng Tip of leaves All leaves Plant dead rolled into tubes

or withered

into tubes or withered

Biyuzaonuo Normal All leaves Plant dead

Reimei Tip of leaves Tip of All leaves rolled leaves rolled into

rolled tubes or withered

Zhonghua 8 Tip of leaves Normal All leaves rolled rolled

Table 2. Cold tolerance of 78 rice varieties at the 3-leaf stage. Hangzhou, China.

Tolerant

Medium tolerant

Medium

Medium susceptible

Suscep- tible

Ainanzao 39, Zaofengshou, Reimei, Fujikei 131, 81y4-5, Zhonghua 8, Fujikei 137, Akita 32, Wujiegu, Titanio, Yantouqing, Fujisaka 5, Fujikei 130, Longjiangdao. Guiluai 8, Daguangxian, Leyi, Erjiulu 1, Qishirihuodao, Yuanfeng- zao, Wenzhouqing.

Zhenlong 13, Simei 2, Ejiunan 1, Chum 84-508, Eza 6, Zhuyunnuo, Yuan 2, Zaoxian 503, ZaoIian 31, Fangyangu. Zhenshan 97, Zaoxian 141, Wenge Zhong 83-49, Zhengui 51, Zuo 5 Zhuke 2, IR24, Huazaobai, Butuoai, ZRE8. Ainanzao l, Nongsheng, Jinke 5, Qing- zhen 16, Hongtu 5, Hongtu 27, Fulianai, Fuyul, Qingganhuang Zhefu 802, Wenxuanqing, Biyuzao- nuo, Luhongzao 1, Zhuxi 26, IR26, IR29, IR36, IR60, B3, Hongtu 31, Erjiufeng, Guangluai 4, Erjiuqing, Qingxiaojinzao, H1459, Junlianzao, Fu 8-1, Chaoyang 1, Aichang 25, Zhenyu, Guiluai 3, Erjiulong, Zaojianzaodao, Liantangzao, 5010, Xianfeng 1.

Seedlings of 5 varieties were grown in 50- × 20- × 15-cm plastic trays with 10 cm soil. At the 3- to 4-leaf stage they were subjected to low temperature (10/6 °C day/night) for 3, 7, and 9 d in the incubator. Incubation for 7 d was best for discriminating cold tolerance among varieties (Table 1).

Leaf rolling was the most visible abnormality and might be useful as a sensitive criterion of cold tolerance. It is more simple and practical than using leaf discoloration or dead seedling percentage.

stage at 10/6 °C day/night for 7 d. The first leaf from the top rolled first, then the second leaf, then all leaves rolled or were fully withered. Varieties could be divided into five cold tolerance groups by leaf rolling symptoms (Table 2):

T = tolerant, all leaves normal MT = medium tolerant, tip to 1/2 of 1st

leaf rolled (leaflet normal)

We evaluated 78 varieties at the 3-leaf

Effect of low temperature on selected rice varieties in Tanzania

M. N. W. Mnzava, Usangu Irrigation Project, Mbeya-Tanzania; and B. S. Vergara and R. M. Visperas, Plant Physiology Department, IRRI

In the Usangu Plains in the south and Moshi and Mombo in the northeast,

Promising cold-tolerant Tanzanian rice varieties.

IRGC acc. no.

Variety

M = medium, 1/2 to 2/3 of 1st leaf

MS = medium susceptible, 1st and 2d rolled (leaflet normal)

leaves fully rolled (leaflet normal) or 1st leaf fully rolled

fully withered. S = susceptible, all leaves rolled or

All of the eight japonicas tested were tolerant. Seven of the 12 tolerant indicas were traditional native varieties. Most of the recommended indica varieties were susceptible. Guiluai 8, Ainanzao 39, and Zaofengshou have been proposed as donors in developing cold-tolerant indica varieties.

low temperature affects the rice crop. Minimum temperatures below 15 °C from late Apr and Aug reduce yield if panicle initiation or heading occurs during the cool period.

We screened 65 Tanzanian varieties from the International Rice Germplasm Center collection for cold tolerance at seedling, panicle initiation, and anthesis (heading) stages in cold water tanks and in the IRRI phytotron.

Score a at seedling

stage

Spikelet sterility (%)

Panicle Anthesis initiation

56208 56209 06485 06481 56163 56164 56181 56184 56194 56195 56205 56210 56213 06479 06480 06491 56161 56167 56168 56183 56186 56192 56193 56214 07533

ES076 ES077 (Shingo) Afaa Kilombero 1-196 Afaa Mwanza 1-104 ES010 (Supa India) ES013 ES040 (Turiani) ES043 ES059 (Bishore) ES060 (Kialangawa) ES072 ES078 (Zira) ES081 (Shindano) Gamti 1-34 Afaa Mwanza 0-746 Lindi Safari ES003 ES018 (Gold) ES018 (Straw) ES042 ES044 (Wahi) ES053 (Ringa) ES054 ES082 HR19

3 3 9 9 9 9 9 9 9 9 9 9 7 9 9 9 9 9 9 7 9 9 9 9 9

– –

10 19 18 23 23 24 16 22 15 19 17 37 57 77 33 26 42 30 60

67 60 52

–

17

18 78 16 30 15 38 13 63 24

–

–

15 15 6

10 13 8 9

13 3

10 12 16

–

a Standard evaluation system for rice score.

14 IRRN 13:4 (August 1988)

ES076 and ES077 were tolerant of Gamti, Afaa Mwanza 0-746, Lindi Kilombero 1-196, Supa India, ES040, 12 ºC water at the seedling stage (see Safari, ES003, ES018, ES042, ES044, ES059, and ES072 were tolerant at table). Afaa Kilombero 1-196 was highly ES053, ES054, ES082, and HR19 were panicle initiation and heading. tolerant and Afaa Mwanza 1-104, Supa tolerant of 21 ºC air temperature for 5 d Afaa lines, Supa India, and Kihogo, India, ES013, ES040, ES043, ES059, during anthesis. the varieties commonly grown, are ES060, ES072, ES078, and ES081 ES076 showed tolerance at both tolerant at panicle initiation, but tolerant of 17 ºC night air temperature seedling stage and heading. Afaa susceptible at anthesis. for 5 d during panicle initiation.

Response of rice varieties to planting time during the dry season

K. Maity and P. K. Mahapatra, Orissa University of Agriculture and Technology, Bhubaneswar 3, India

In parts of Orissa, rice is grown early in the dry season (DS) using water from streams, tanks, and ponds that dry up in Apr and May. We studied varietal response to different planting times during Dec and Jan. The trials were laid out in a replicated split-plot design in DS 1985 and 1986. Varieties Pathara, Kuber, and Rajani were studied in 1985; Pathara, Rajani, Annapurna, and Shankar in 1986. Temperature profile during the rice-growing season. Bhubaneswar, India, 1985-86.

Soil was laterite, loamy sand, with pH 5.6, 0.4% organic carbon, 0.04% total N, 12 kg available P, and 150 kg available transplanting dates, at 154 intervals, and 5 Jan 1987 produced the highest. K/ ha. Seedlings were transplanted at started 5 Dec 1985 and 10 Dec 1986. Late and early planting reduced yield, 25 d at 15- × 10-cm spacing with 60-13- Time of planting affected yield (see perhaps because of temperature (see 25 kg NPK/ha. Full P and K and 25% table). Transplantings on 25 Dec 1985 figure). N were applied basal, 50% N at tillering, and 25% N at panicle initiation. Four

Effect of date of transplanting on yield of different rice varieties. Bhubaneswar, Orissa, India, 1985-86.

Treatment Yield (t/ha)

1985 1986

Planting date 5-10 Dec

20-25 Dec 5-10 Jan

LSD (0.05) 20-25 Jan

Variety Pathara (OR83-23) Kuber (ORl64-5) Rajani (ORl63-104) Annapurna Shankar

LSD (0.05)

2.8 3.1 3.7 3.3 0.5

3.1 3.1 3.5 -

0.3 -

2.0 2.6 2.4 2.2 0.1

2.3

2.4 2.6 1.9 0.1

-

Inheritance of seedling stage cold tolerance in 6 indica and japonica crosses

Xu Yunbi and Shen Zongtan, Agronomy Department, Zhejiang Agricultural University, Hangzhou, China

We used highly cold-tolerant japonica varieties Zhonghua 8 and Reimei as the female parents (P 1 ) and cold-susceptible indica varieties Ejiufeng, My 821 66, Qinghuaai 6, and Conggui 314 as the male parents (P 2 ) to make six crosses (two including B 2 , F 1 /P 2 ) between indicas and japonicas in 1985-86.

The seeds were sown in 50- × 20- ×

15-cm plastic trays, one cross (including P 1 , P 2 , F 1 , F 2 , B 2 )/tray. Seedlings at the 3-leaf stage were subjected to 10/6 ºC day/night, 12 h light (2500-3500 1x)/d for 7 d in the incubator. We used leaf rolling as the criterion for cold tolerance.

All F 1 s showed good tolerance for low temperature. The F 2 and B 2 populations had only R or S seedlings. Segregation of F 2 plants in 6 crosses fit a 15:1 inheritance ratio, B 2 plants in 2 crosses fit 3:1 (see table). That shows that cold tolerance indicated by leaf rolling in indicas and japonicas is governed by two dominant duplicate genes.

IRRN 13:4 (August 1988) 15

Segregation on cold tolerance at the seedling stage in F 2 and B 2 populations of 6 indica/japonica crosses. a Hangzhou, China, 1985-86.

F 2 and B 2 X 2 c b

P 1 P 2 F 1 Cross T S T Total T S B 2 (3:1)

F 2 (15:1) P

Zhonghua 8/Erjiufeng 50 38 17 F 2 207 191 16 0.5414 0.25-0.50 B 2 36 28 8 0.0370 0.75-0.90

Zhonghua 8/My 82166 24 40 12 F 2 181 169 12 0.0033 >0.90 Zhonghua 8/Qinghuaai 6 24 39 25 F 2 184 170 14 0.3710 0.50-0.75

B 2 55 40 15 0.0545 0.75-0.90 Zhonghua 8/Conggui 314 50 31 19 F 2 198 185 13 0.0013 >0.90 Reimei/Qinghuaai 6 42 39 31 F 2 195 187 8 1.1901 0.25-0.50 Reimei/Conggui 314 27 31 29 F 2 144 133 11 0.2667 0.50-0.75

The International IPM Newsletter is published for researchers in the development and transfer of integrated pest management (IPM) technology in rice production. Its content focuses on discussions of current issues; it does not publish research reports. For more information, write Dr. B. M. Shepard, IPM Newsletter, IRRI, P. O. Box 933, Manila, Philippines.

a T = tolerant, S = susceptible. b No segregation into medium type seedlings such as medium tolerant, medium, medium susceptible.

Adverse soils tolerance

Effect of soil alkalinity on important plant nutrients.

yield of genotypes in Kanpur in plots with pH values 9.2 and 9.6. N- We screened 10 genotypes (see table)

B. Singh and O. P. Srivastava, Soil Science P-K was applied at 120-26-25 kg/ ha and Agricultural Chemistry Department, C. through urea, single superphosphate, S. A. University of Agriculture and and muriate of potash. Technology, Kanpur 208002, India Maximum grain yield was from

Alkali soils occur more in arid and IR4563-52-1-1-3-6. Lowest yield was semiarid areas. Because of high pH from IR54. Grain yield was severely values, these soils are deficient in reduced with increasing pH.

Pokkali, Nonasail (Sel.), IR46, and

Effect of soil alkalinity on grain and straw yields. Kanpur, India.

Grain yield Straw yield (t/ha) (t/ha)

pH pH pH pH Variety

9.2 9.6 9.2 9.6

IR43 IR46 IR54 IR4563-52-1-1-3-6 IR9763-11-2-2-3 IR14632-2-2-3 IR19661-131-1-2 M242 Nonasail (Sel.) Pokkali

Mean

2.9 1.8 5.5 3.9 3.5 2.8 5.6 3.8 1.8 0.5 4.2 3.2 3.7 2.5 4.0 3.9 2.9 2.8 3.7 3.5 2.1 2.0 8.1 7.5 2.8 2.2 5.1 3.8 2.5 2.3 4.8 4.0 3.6 3.0 6.5 5.7 3.6 2.8 6.8 4.7 2.9 2.3 5.4 4.4

Screening rice entries for coastal salinity and tidal swamp conditions

S. Gupta, Rice Research Station, Chinsurah, Hooghly, India

We screened 115 germplasm and advanced breeding lines for adaptability to coastal salinity and tidal swamp conditions in the coastal area of south 24-Parganas district, West Bengal.

Tidal water was allowed to enter the plots at regular intervals. The Ece of the soil at transplanting of 30-d-old seedlings was 8.4 dS/m; that of groundwater was 29.9 dS/m. On the commencement of rainfall, those values gradually decreased to a 3.0 for soil and 11.0 for groundwater at 38 d after transplanting (DT). Soil Ece values were

16 IRRN 13:4 (August 1988)

Survival, days to 50% flowering, plant height, panicles, and yield of 12 promising entries for coastal salinity and tidal swamp areas. Hooghly, India.

Survival (%)

Days to 50%

flowering (g) Height Panicles (cm) (no.)

Yield/ plant Variety or line

Silla Djambaram BJN4 BJM5 IR37257-41-3-2-3 IR39558-147-1-3 IR40578-13-2-2-3-2-2 IR4595-4-1-13 IR10198-66-2 SR26B Hamilton Malta

19.1 18.2 21.8 18.2 37.3 47.3 28.2 31.8 27.3 31.8 38.2 31.8

131 122 129 132 111 132 93

122 108 110 103 103

90.6 100.4 67.4 84.2 96.5 69.2 73.8 78.6 91.5

106.2 103.2

98.6

6.0 7.4

12.0 11.4

9.4 9.8 5.0 6.4 9.3 7.0 9.4 5.4

5.5 11.7 14.3 10.5 16.6

6.2 15.2 18.5 21.7 16.5 19.2 13.3

below 5.0 dS/m and those of at 89 DT. groundwater 10 dS/m and below, from Percentage survival, days to 50% 38 to 68 DT, then tended to increase. flowering, plant height (cm), Highest soil Ece value (15.1 dS /m) was panicles / plant, and yield of 12

promising entries are given in the table. Highest survival was in IR39558-147-1- 3, but because of its longer duration, most panicles did not exsert fully with high salinity and low temperature during Nov.

IR4595-4-1-13-2, IR37257-41-3-2-3, IR40578-13-2-2-3-2-2 with flowering durations of 122, 111, and 93 d, appear most promising. Considering the growth

duration suitable for local situations, IR10198-66-2-1 showed promise.

Among four local varieties tested, Hamilton was most adapted.

Integrated germplasm improvement

Performance of early Prasanna variety

M. V. S. Sastry and U. Prasada Rao, Directorate of Rice Research, Rajendranagar, Hyderabad 30, India

We grew 3 crops of Prasanna in sequence in 2,000 m 2 under restricted irrigation at Ramachandrapuram during 1986-87. Sowing was 7 Jul (normal wet season), 22 Aug (midseason), and 20

Dec (normal dry season). Twenty-day- old seedlings were planted at 15- × 15- cm spacing with moderate fertilizer (13- 17 kg P-K + 40 kg N/ha). Irrigation at

10-d intervals was applied when there was no rainfall during the 10-d period.

All crops matured in 90 d (see table). Comparing the yields of the Aug and Jul sowings indicated the suitability of Prasanna for midseason planting. Total yield for the year was 8 t/ha, with a 210- d cropping period.

Performance of Prasanna in a 3-crop year. Hyderabad, India, 1986-87.

Sowing date Transplanting date Maturity Days to maturity Yield (t/ha)

4 Jul 22 Aug 20 Dec

24 Jul 4 Oct 90 6 Sep 22 Nov 90

10 Jan 20 Feb 90

2.4 2.6 3.0

A high-yielding variety for coastal Andhra Pradesh, India

P. Sankar Rao, N. Sree Rama Reddi, and C. B. Rao, Agricultural Research Station (ARS), Maruteru 534122, A. P., India

Agronomic traits and blast resistance of MTU7014 at Maruteru, India, 1986 dry season.

Character MTU7014 IR64 BPT 1235 (local check)

Plant type

Growth duration (d) Plant height (cm) Panicles (no./m 2 ) Spikelets (no./panicle) Filled spikelets (no./panicle) Sterility (%) 1000-grain weight (g) Pigmentation Seed dormancy (wk) Reaction to blast a

MTU7014, a high-yielding, early- maturing, blast-resistant variety, is a derivative of Rasi/IR19667-131-1-2. It consistently yielded higher than BPT1235 in replicated trials during the 1985, 1986, and 1987 dry seasons (see table). In 1987 minikit farmers' field trials at 23 locations in Godavari District, MTU7014 yielded higher than local check BPT1235.

Compact tillers dark green foliage

125 84

491 99 97

2.2 29

Green 4 1

Compact tillers light green foliage

120 85

433 127 125

28 1.8

Green 3 1

Low tillers, light green foliage

120 86

528 93 92

25 1.1

Purple 2 8

a Standard evaluation system for rice scale 0-9. Tested against race IC 9.

Two new varieties from segregation material of IR36

Wei Zisheng and Li Yourong, Hunan Agricultural Science Academy, Rice Research Institute, Changsha, Hunan, China

IR36 has a growth duration that is too long for an early rice crop in Hunan. We used it as a source of resistance

Yield, growth duration, and pest resistance of 2 new varieties in Hunan, China.

Grain yield Growth duration Reaction a to Variety (t/ha) (d)

BB B1 BPH WBPH

IR36 (female) 7.1 125 R R R Guong jei 9 (male) – 109 S R S Xiang Zaoxian 3 7.0 106 R R R R HA79317-4 6.6 102 R R R R

– –

a R = resistant, S = susceptible.

IRRN 13:4 (August 1988) 17

genes for bacterial blight (BB), rice blast (Bl), and brown planthopper (BPH).

Two early rice varieties with medium growth duration—Xiang Zaoxian 3 and

Three rice varieties named in Ghana R. C. Dekuku, Crops Research Institute, P. O. Box 52, Nyankpala - Tamale, Ghana (present address: Plant Breeding Department, IRRI)

In Ghana, rice is cultivated mostly under rainfed conditions.

HA793 17-4—have been selected from segregating material of IR36/ Guong jie 9. They have resistance to BB, Bl, BPH, and whitebacked planthopper (WBPH),

C168 from the cross Intan/BPI-76-1 from the Philippines, IR1750-F5-B5 from the cross E425/IR22 from IRRI, and ToX 516-19-Sel from the cross Moroberekan/ Juma I, ToX 7-3-2-3-2, and SE3639 from the International Institute of Tropical Agriculture (IITA) were selected from IRTP trials early in the 1980s.

Table 1. Grain yield and reactions to blast and brown spot of GR19, GR20, and GR21 under rainfed conditions at research sites in Ghana, 1981-85.

Variety Grain yield (t/ha) Reaction a to

1981 1982 1983 a 1984 1985 Mean b Blast Brown (1 site) (2 sites) (2 sites) (3 sites) (9 sites) spot

GR19 (C168)

GR20 (IR1750-F5-B5)

GR21 (ToX 516-19-Sel)

Check variety Tamale 1

3.8

4.4

4.4

2.4

2.1

2.4

2.4

1.4

1.2

1.6

1.0

1.0

2.6

1.7

2.8

1.4

2.0

2.1

2.5

1.8

2.3 (46%)

2.4 (53%)

2.6 (65%)

1.6

3

2

3

5

2

3

3

7

a Rainfall deficit was 247-288 mm at trial sites. b Percentages show yield increase over check variety. c By the Standard evaluation systems for rice scale.

Table 2.On-farm trial grain yield of GR19, GR20, and GR21 in Ghana, 1985 and 1986.

Grain yield (t/ha)

GR19 GR21 GR20 Local check Site

Nayoko Zawse Zabgo Gore Vane

Mean

Tarkpaa 1 Tarkpaa 2 Tarkpaa 3 Cheshegu Zuarungu Soe 1 Soe 2 Bladjei Katiejeli Tarkpaa 4 Kete Krachi Kpassa/Nkwanta Central Volta Gbefi Vane

Mean

2.6 2.2 0.9 0.4 3.4 1.9

2.2 2.9 1.7 2.4 3.7 0.9 5.2 1.5 0.9 3.0 2.9

a

2.6 3.3

a

2.6

2.8 2.8 1.7 0.6 4.9 2.6

2.4 1.8 1.2 2.2

0.8 5.2 1.6 0.6 3.1 3.5 3.3 2.9

a

3.9 2.3 2.5

1985 2.9 2.8 2.3 1.3 2.7 2.4

1986

1.7 1.6 2.2 0.5 2.8 1.8

1.3 2.1 0.8 1.4 2.9 0.7 5.6 1.1 1.3 3.0 3.8 1.4 1.0 1.2 2.0 2.0

a Not included.

18 IRRN 13:4 (August 1988)

and high yield (see table). By 1987, they had been planted in 500,000 ha in Hubei, Jiangxi, Guongxi, and Zhejiang Provinces.

They consistently have outyielded most other varieties and local checks under rainfed lowland shallow conditions at research sites (Table 1). Even in 1983, with a Jun-Oct growing season rainfall of only 497 mm at Nyankpala and 547 mm at Manga, compared to the 30-yr average 785 mm and 794 mm, yields equaled or were higher than those of the check varieties.

On-farm test yields in 1985 and 1986 also were encouraging (Table 2), and in 1987 the Ghana Rice Varietal Release Committee accepted GR19 (C168), GR20 (IR1750-F5-B5), and GR21 (ToX 516-19-Sel) for rainfed cultivation.

GR19 (100 cm tall) matures in about 120 d; GR20 (90 cm), in 105 d; and GR21 (90 cm), in 110 d. All have acceptable cooking and eating qualities and are resistant or moderately resistant to leaf blast and brown spot.

Red Triveni, a promising short-duration variety for India

K. Karunakaran, K. I. James, C. A. Rosamma, P. Chandrika, and N. R. Nair, Regional Agricultural Research Station, Pattambi 679306, India

Of three short-duration, semidwarf, high-yielding rice varieties released in Kerala, Triveni is the most popular among Kerala farmers. Farmers who have a strong preference for red grain have been asking for a red-grained version, adaptable to all growing seasons.

About 5 yr after Triveni’s release, a few isolated red-grained plants were found. Red-grained plants reoccurred, despite strict roguing.

White-grained PTB15, one of the parents in the evolution of Triveni, has purple tipping. Possibly, segregation for

cpsadmin

Line

cpsadmin

Line

an inhibitory factor caused the red- grained plants.

Single plant selection and progeny testing were carried out systematically and the nonsegregating red lines bulked and multiplied. The new line was designated Red Triveni and tested in replicated yield trials during the three main rice seasons 1985-86.

The new culture with red grain uniformly performed well during the three seasons (see table). In adaptive trials in farmers’ fields in three districts

Performance of Red Triveni in wet, dry, and summer seasons. Pattambi, Kerala, India, 1985-86.

Days to 50% flowering Grain yield (t/ha) Variety

Summer Kharif Rabi Summer Kharif 1985-86

Rabi 1986 1986

Red Triveni 78 94 74 4.8 4.1 3.3 Triveni 78 94 78 4.4 3.8 2.7 Annapoorna 77 89 67 4.3 3.7 2.6 Rohini 76 99 65 4.3 3.8 2.4

LSD (P = 0.05) ns ns 0.2

in summer season 1987, Red Triveni original white-grained Triveni averaged yields averaged 6 t/ha (yields of the 5.2 t/ha).

A blast (BI)-resistant and high-yielding early indica Fu 8-1 is a newly released semidwarf

variety indica variety induced from variety 8004 with Co 60 r-ray (3.5 krad). It has 115-

Xiong Zhenmin and Wang Guoliang, China 120 d duration, 1-2 d earlier than National Rice Research Institute, Hangzhou, popular local variety Guang-Lu-Ai 4, China with wide adaptability in Zhejiang,

Table 1. Some agronomic characteristics a of Fu 8-1. Hangzhou, China, 1986-87.

Variety Duration Panicles Grains 1000-grain Seed Yield a

(no./m 2 ) (no./panicle) wt (g) (%)

(t/ha) (d) (cm)

Fu 8-1 114 75.8 472.26 69.7 32.2 76.6 7.5 Guang-Lu-Ai 4 114 67.4 533.73 66.7 25.2 78.1 6.9

Jiangxi, Hunan, and Hubei Provinces (26.0-31.0°N, 114-120°E).

The new variety performed well in the regional trials of Zhejiang Province in 1986 and 1987—average yields 7.5 t/ha, nearly 9% higher than Guang-Lu-Ai 4 (Table 1). Grain quality is also better.

An outstanding characteristic of Fu 8- 1 is its widespectrum resistance to rice Bl caused by Pyricularia oryzae. In 1986 artificial inoculation tests, it was resistant to 26 and moderately resistant to 1 of 29 local isolates (Table 2). It also has good field resistance.

a Mean of 7 sites.

Table 2. Reaction of Fu 8-1 to 29 P. oryzae isolates belonging to groups A to G. a Hangzhou, China, 1986-87.

Reaction b

A7 B11 B15 B3 B19 C15 D3 D7 E1 E3 G1

Variety 15- 14- 18- 31- 34- 52- 15- 15- 20- 51- 51- 64- 18- 43- 83- 14- 90- 71- 82- 85- 49- 36- 49- 46- 16- 6- 7- 21- 9- 1 2 9 2 2 3 4 1 2 4 4 4 5 1 4 1 1 1 1 4 4 3 4 2 1 3 2 2 3

Fu 8-1 M R R R R R R R R R S R R S R R R R R R R R R R R R R R R Guang-Lu-Ai4 S S S S S S S S S S S S S S S S S R R R S S M R S S S S S

tible. a Grouping based on Chinese differentials. Each letter is followed by the race number in that group. b R = resistant, M = moderately resistant, S = suscep-

OM91: an improved rice variety for high-production irrigated areas

Nguyen van Luat, Pham cong Voc, and Nguyen van Loan, Cuu Long Delta Rice Research Institute (CLRRI), Omon, Haugiang, Vietnam

OM91 was found to be widely adapted In several provincial trials. It has higher

Table 1. Yield of OM91 at CLCRRI, Omon Haugiang, Vietnam, 1984-86.

Yield (t/ha)

Variety Dry season Wet season

1983 1984 1985 1984 1985 Average

OM91 4.6 4.4 5.8 NN7A 4.8 3.9

6.8 4.5 5.8 5.7 6.3 4.5 5.0

CV (%) 7.3 13.7 14.6 13.7 14.6 – LSD % 0.7 0.6 0.7 0.6 0.4 –

IRRN 13:4 (August 1988) 19

ht Plant

set

significant. In 46 samples of IR42 and 21 samples

of Moc Tuyen from farmers’ fields, we

areas of the Red River delta, about 3,400 ha of IR42 was grown in medium water depth (30-40 cm), next to some widely grown local varieties (Moc Tuyen, Bao Thai, and others). We studied its performance in three districts.

IR42 (30 d old) was transplanted with about 10 t farmyard manure (60 kg N)/ha and 17.6 kg P/ha (no K). Damage by pests and diseases was not

Rice variety IR42 was introduced in Vietnam in 1977. We compared it with some other varieties in the wet season (Jun-Oct) field trials (Table 1).

In 1987 wet season in Ha Nam Ninh, Ha Bac, and some other deepwater rice

Performance of IR42 in deepwater rice areas on the Red River delta in northern Vietnam

M. Rangaswamy, Rice Research Station, Ambasamudram; and S. R. Sree Rangasamy, School of Genetics, Tamil Nadu Agricultural University, Coimbatore, India

Dao The Tuan, Nguyen Duy Tinh, Bach Trung Hung, Nguyen Manh Trung, and Pham Van Chinh, National Institute of Agricultural Sciences, D7, Phoung Mai, Dongda, Hanoi, Vietnam

found the following: IR42 yields averaged more than

5 t/ ha in 22% of the samples, 4-5 t/ha in 61%, and 3-4 t/ha in 17%.

Moc Tuyen yields were higher than 5 t/ha in 19% of the samples, 4-5 t/ha in 29%, and 34 t/ha in 52%.

A trial to standardize A line seed production techniques was conducted in summer 1986. Zhen Shan 97 A was used as the B line in the ratios 1:1, 2:1, 3:1, 4:1, 5:1, and 6:1. To synchronize flowering and prolong pollen supply, alternate hills of B line were pruned

and more insect and disease resistances than local check NN7A.

a 90-95 d growth duration, compact tillering, and slender white grain. Yields averaged 5.8 t/ha in the 1984-86 CLRRI and multilocation yield trials (Table 1).

OM91 is highly resistant to brown planthopper biotype 2 and to blast (Bl). It withstood high Bl pressure in Binh Minh district, Cuu Long Province, seed station trials (Table 2).

OM91 was released for large-scale cultivation in the Cuu Long Delta in 1987.

OM91, from the cross 900/IR747, has

Table 2. Reaction of OM91 to insect pest and disease a in Cuu Long Delta in 1984-85.

Blast

Hau Giang An Giang Cuu Long

Score Reaction Score Reaction Score Reaction

Variety Brown planthopper

OM91 3 R 2 R 2-3 R-MR 2-3 R-MR NN7A 3 R 8 HS 8 HS 9 HS NN6A 3 R 9 HS 9 HS 9 HS

a Artificial infestation, using IRRI test and scoring procedures. R = resistant, HS = highly susceptible. Resistant check for BPH = IR36, Bl = IR. Susceptible check for BPH = TN1, Bl = NN7A.

For information on ordering IRRI publications, write Communication and Publications Dept., Div. R, IRRI, P. O. Box 933, Manila, Philippines.

Table 1. Yield trials in 1977-83 wet season. a

Av grain yield (t/ha)

Year IR42 IR22 BR52-87-1 Moc Tuyen b

1977 4.6 4.0 1978 4.9 3.8 1979 5.1 5.3 1980 4.7 3.8 1982 5.9 – 5.5 1983 2.7 –

a Source: National Institute of Agricultural Sciences. b Photoperiod-sensitive, China variety.

– – – – – – – –

– – 2.3

Table 2. Av grain yield by sowing dates of IR42 in 1987 wet season.

Samples (no.) by average yield Sowing date

Over 5.0 t/ha 4.5-5.0 t/ha 4.0-4.5 t/ha Less than 4.0 t/ha

25-30 May 6 3 4 1-5 Jun 2 2 3 6-10 Jun 2 6 6

– – 6

11-15 Jun – 3 1 2

IR42 responded to time of seeding with less than 4 t/ ha were sown 6-15 (Table 2). Most crops that yielded more Jun. Best seeding time was late May to than 5 t/ ha were sown 25-30 May; crops early Jun.

Seed technology

Standardizing hybrid rice A line seed production

20 IRRN 13:4 (August 1988)

15 cm above the ground 25 d after the table. equal in 4:1, 3:1, 2:1, and 5:1 row ratios, planting. Pruned hills flowered 1 wk Yields of A lines with pruned and and significantly superior to those at 6:1 later than nonpruned hills. Yield and nonpruned B lines were not significantly and 1:1. A line seed set was high with percentage of seed set are presented in different. Seed yields of A line were 1:1 row ratio and low with 6:1.

Seed yield and seed set in Zhen Shan 97 A line with different planting ratios. Coimbatore, India, 1986 summer.

A line seed set a (%) A line seed yield b

A:B ratio B line B line Mean Compared B line pruned B line nonpruned Mean % over pruned nonpruned with 1:1 yield 1:1

Yield % over Yield % over (g/m 2 ) (g/m 2 ) 1:1 (g/m 2 ) 1:1

1:1 2:1 3:1 4:1 5:1 6:1

Mean % over nonpruned

LSD

19.3 18.8 16.9 17.4 15.5 13.6

16.9 103.0

–

18.5 17.9 16.5 15.8 14.1 12.8

15.9 100.0

–

18.9 18.4 16.7 16.6 14.8 13.2 16.4

–

1.6

100.0 97.4 88.4 87.8 78.3 69.8 86.8

–

–

49.5 61.6 62.4 64.3 60.5 56.5 59.1

–

–

100.0 124.4 126.1 129.9 122.2 114.1

119.4 109.6

–

45.6 55.7 58.2 57.6 55.3 51.2

53.9 –

–-

100.0 122.1 127.6 126.3 121.3 112.3

118.2 100.0

–

47.5 58.6 60.3 60.9 57.9 53.8

56.5 –

4.3

100.0 123.4 126.9 128.2 121.9 113.3 118.9

–

–

a Seed set: between A and B ratios = significant at 5% level; between B line pruned and nonpruned = not significant. b Seed yield: between A and B ratios = significant at 1% level; between B lines pruned and nonpruned = not significant.

Varietal differences in seed longevity

H. P. Sikder, Rice Research Station, Chinsurah, Hooghly, West Bengal, India

We studied seeds of 32 rice varieties (8 dwarf ponlais; 12 dwarf indicas, and 12 tall indicas) under adverse storage conditions.

Seed samples (3 per variety) were thoroughly dried in the sun after Nov harvest and kept in thin cloth bags in ambient conditions. Germination percentages were recorded monthly Mar-Sep, with relative humidity and atmospheric temperature. (Seeds were germinated in petri dishes on moist blotting paper for 6 d.)

of germination percentages: Highly resistant = more than 80% germination. Moderately resistant = germination

Weakly resistant = germination less than 40%.

The ponlai group appears to be highly susceptible to adverse storage conditions (see table). By Jun, ponlai varieties had

Varieties were classified on the basis

40-80%.

Resistance of rice varieties to loss of viability in storage. Hooghly, West Bengal, India.

Varieties

Weakly resistant Moderately resistant Strongly resistant Rice group

Dwarf ponlais Taichung 65 Kalimpong-I a

Kalimpong-II a

Tainan 3 Kaohsiung 68 Chianung 242 Chia 242 × CI 9155 IR60-1241 b

Dwarf indicas TN1 × Taichung 65 Taichung Native I IR8-178-3-1 IR4-67-2-3 IR4-90-2

Tall indicas Churnakati NC1626 Badkalamkati 65 Nagrasail

IR9-60 IR8-288-3 IR8-64-3-1 IR8-190-1 IR5-47-2 IR5-114-3 IR4-263-1-2 FR43B OC1393 Kumargore Tilakkachari

SR26B Ramsail

Bhasamanik Bankura 517

a Selection from ponlai. b With ponlai-lie plant type.

become unsuitable for sowing. Among varieties. The long-duration local the tall indicas, short-duration varieties also have strong dormancy. Churnakati and Badkalamkati 65 were Even though high-yielding dwarf much weaker than long-duration varieties have short duration and mostly

IRRN 13:4 (August 1988) 21

1. Schematic of experimental setup used to oxidize or reduce soil in the laboratory. Louisiana State University, Baton Rouge, USA, 1988.

reduced soil suspension was extracted by preflushing the bottles with N 2 ; O 2 -free KCl-PMA solution also was used for

extraction. The supernatant solution of the reduced soil samples was filtered under a N 2 atmosphere. The unhydrolyzed urea recovered in the KCl-PMA extracts was determined colorimetrically immediately after extraction.

Urea hydrolysis in oxidized and reduced flooded soil

weak or no dormancy, their storage life varied widely. Viability appears to be controlled by genetic factors; dwarf indica TN1/Taichung 65 lost viability very quickly.

In general, the gradual fall of seed viability was due to the increase in relative humidity (58% to 85%), and in temperature (26 to 31°C).


CROP AND RESOURCE MANAGEMENT Soils and soil characterization

C. S. Khind, C. W. Lindau, and W. H. Patrick, Jr., Laboratory for Wetland Soils and Sediments, Center for Wetland Resources, Louisiana State University, Baton Rouge, USA

We studied urea hydrolysis in oxidized and reduced soil systems in a controlled laboratory setup (Fig. 1). Soil was an Oxisol, kaolinitic clay (Typic Haplorthox) with pH 5.2, 1.72% organic C, 0.13% N, and CEC 15.5 meq/ 100 g. It contained 56.2% clay, 11.9% silt, and 31.9% sand.

Four hundred grams of 2 mm air- dried soil (oven dry weight basis) and 1,600 ml of water were placed into a 2- liter conical flask, stirred continuously with a magnetic stirrer, and incubated in the dark at 25 °C. Stable soil redox conditions and pH were obtained by continuously purging the soil suspension with 99.9% O 2 (for oxidized conditions) or 99.9% N 2 gas (for reduced conditions) for about 30 d before adding urea. Duplicate flasks were run for urea and no N treatments.

and the contents of the flasks stirred continuously, purging either with O 2 or N 2 gas. Duplicate 25-ml aliquots of soil suspensions were removed 0, 0.5, 1, 2, 4, and 7 d after adding urea. The aliquots were used to determine oven-dry soil weight and urea N.

The oxidized soil suspension was extracted with KCl-PMA solution having a final concentration of 2M. The

Urea was applied at 200 mg N/ kg soil

22 IRRN 13:4 (August 1988)

Influence of P, K, micronutrients, and dolomite on azolla growth

G. Rakotonaivo, Université de Madagascar, Service Botanique, B. P. 906, Antananarivo, Madagascar; and M. Schramm, Humboldt University, Biology Department, Berlin 1040, German Democratic Republic

We studied the effects of P, K, micronutrients (M), and dolomite (D) on azolla growth and its P accumulation in 1.2- × 2.3-m plots in a randomized complete block design with 3 replications. The test was conducted at 1,260 m altitude at the end of the warm season Mar 1985 (air temperature 16- 25 °C; water temperature 11-40 °C) in Antananarivo.

Soil was sandy clay loam mineral hydromorph, with pH 5.2, 1.13% total P, 0.155% Olsen P, 3% organic matter, 1.7% C, and ex-K 0.18 meq/100 g.

Treatments were P alone; P and K; P, K, and M; P, K, and D; and P, K, M,

and D. P was applied at 7 kg/ ha as triple superphosphate, K at 5 kg/ ha as KCl, and M at 10 kg/ha as a commercial cocktail containing 0.3% B, 1.5% Fe, 0.5% Cu, 1.5% Mn, 0.01% Mo, 1.5% Zn, 4% MgO, 5% N, and 5% S. Dolomite was applied at 300 kg/ ha. P was applied weekly at 7 kg/ ha; the other materials were applied only at the beginning of the test. Dolomite was applied to estimate the influence of pH changes.

Azolla pinnata var. pinnata (var. africana ) was inoculated at 50 g/plot. Azolla fresh weight and P accumulation were recorded 37 d after inoculation.

Results show that P is essential to azolla growth (see table). Fronds cultivated with P were reddish green. P- deficient fronds were reddish brown, and their roots were long and easily detached. Dolomite, micronutrients, P, and K together induced uniform azolla multiplication. K did not influence frond proliferation.

P accumulation was remarkable. Azolla incorporated as green manure could be a source of available P.

2. Urea hydrolyzed in oxidized and reduced flooded Sumatra soil at 25 °C. Louisiana State University, Baton Rouge, USA, 1988.

The results show that rate of urea hydrolysis in the oxidized soil proceeded at a significantly slower rate than in the reduced soil for all the incubation periods (Fig. 2). At 1 d after application, 40% of added urea was hydrolyzed in the oxidized soil, and 62% in the reduced soil. At 4 d, 72% of added urea was hydrolyzed in the oxidized soil, and 93% in the reduced soil. At 7 d, a small amount of urea still remained in the oxidized soil, but no trace was found in the reduced soil.

For instructions on preparation of brief reports of rice research to submit for publication in IRRN, see the inside front cover of this issue.

Soil microbiology and biological N fertilizer

Azolla growth and P accumulation during 37 d at the end of the warm season in 1985, Anta- narivo, Madagascar.

Azolla wt P accumulated

g Increase % Increase Treatment

over over control (%) control (%)

Control 110 – 0.059 – P 270 157 0.197 235 P+K 280 169 0.200 239 P+ K + M 340 218 0.198 236 P+K+D 310 189 0.205 247 P+K+M+D 350 228 0.211 258

LSD (0.05) 101 0.102

Response of flooded rice to green manure

Y. Singh, B. Singh, C. S. Khind, and O. P. Meelu, Soils Department, Punjab Agricultural University, Ludhiana 141004, India

We studied the relative contribution of N from aboveground (shoot) and

IRRN 13:4 (August 1988) 23

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cpsadmin

Line

belowground (root) portions of Sesbania aculeata to wetland rice and the effect of green manure and a nonleguminous crop fortified with fertilizer N on yield and N uptake of rice.

pH 8.2, 0.37% organic C, and 0.08% total N. The experiment, conducted during 1987 wet season, was in a randomized complete block design with three replications. The 12 treatments comprising green manure and urea N are described in the table.

51 d were incorporated 1 d before transplanting rice. Sesbania accumulated 4.1 t dry matter and 125 kg N/ha. Maize accumulated 1.64 t dry matter and 20.7 kg N/ ha. Long- duration rice PR108 was transplanted 27 Jun 1987 in 23.4-m 2 plots at 20- × 15-cm spacing. N as urea was applied in 2 equal splits — 21 and 42 d after transplanting (DT) — in green manure plots and in 3 equal splits — 7, 21, and 42 DT — in fallow and maize plots. All plots received 26 kg P and 25 kg K/ha at final puddling.

At 35 DT, dry matter and N uptake of rice were significantly higher in plots fertilized with sesbania or urea. The plots receiving belowground portion of sesbania showed no significant gain over fallow plots. In maize plots, growth and N uptake of rice did not differ significantly from those in fallow plots. Without green manure, rice responded up to 180 kg N/ha. Incorporating sesbania produced yields equivalent to those with 120 kg N/ha. This shows that efficiency of N contained in sesbania is similar to that of urea N.

sesbania shoots did not differ significantly from those with sesbania grown and buried in situ. This suggests that the mineralizable N in sesbania is contained mainly in the aboveground portions. Yield from plots from which sesbania shoots were removed did not differ significantly from yield in fallow

Soil was calcareous sandy loam with

Sesbania and maize crops grown for

Yields from plots green manured with

plots. Without fertilizer N, incorporation of

the maize crop containing 1.26% N did not prove beneficial. With 60 kg N/ha,

24 IRRN 13:4 (August 1988)

Effect of green manure and N level on growth and N uptake of rice. Ludhiana, India, 1987 wet season.

Treatment Dry matter Grain N uptake (kg/ha) Apparent N at 35 DT yield recovery a

Green manure Urea N (kg/ha) (t/ha) (t/ha) 35 DT Maturity (%)

7.6 31 8.7 41 5.3 19 6.5 26

Sesbania grown and incorporated Sesbania grown and aboveground portion removed Sesbania not grown but aboveground portion from preceding treatment incorporated Maize grown and incorporated Fallow

LSD

0 60

0 60

0 60

0 60

0 60

120 180

1.8 2.3 1.2 1.5

133 164 86

111

1.9 2.2

1.1 1.6 1.2 1.6 1.9 2.0 0.39

7.4 9.0

5.4 7.9

5.0 6.2 7.5 8.6 0.81

28 36

17 26 18 26 33 38

5.1

134 170

89 149

81 109 141 174

11.6

41.6 51.7 b

41.7 b –

42.4 60.0 b

100.0 b 38.1

46.7 50.0 51.7

–

–

a Apparent N recovery of green manure N was calculated by subtracting N uptake in no-N control of fallow treatment. b Value corresponding to apparent N recovery for 60 kg N/ha in the presence of green manure.

maize-incorporated plots produced spectacularly high rice yields, equal to those with 120 kg N/ ha. Total N uptake of rice at maturity showed a similar pattern.

Apparent recovery of fertilizer N was about 50% in fallow plots and 40% from

plots with N applied as green manure. Apparent recovery of fertilizer N in maize plots was surprisingly high. It seems that N applied in maize plots narrowed the C:N of maize residue, which then behaved as a slow-release fertilizer.

Azolla growth under different rice planting methods in Kerala

D. Alexander, Regional Agricultural Research Station (RARS), Pattambi, Kerala; N. Sadanandan, Directorate of Postgraduate Studies, Vellanikkara; and K. Karunakaran, RARS, Kerala, India

A study of the effect of rice planting method on azolla growth during 1980 dry season (Sep-Jan) and 1981 wet season (Jun-Sep) showed that the bulk planting method favored maximum azolla growth. We conducted a more extensive trial during 1981 dry season to confirm this finding.

Yields of azolla and rice as affected by method of planting rice. Pattambi, India, 1981 dry season.

Azolla yield Rice yield (t/ha)

3 wk after inoculation Grain Straw Planting method (g/m 2 )

20 × 10 cm east-west direction 20 × 10 cm north-south direction 40 × 5 cm east-west direction 40 × 5 cm north-south direction Bulk method (equidistant, 50 hills/m 2 ) Fallow (without rice)

LSD (0.05)

182 179 160 181 191 68

15

4.8 4.7 4.3 4.6 4.1 –

ns

3.3 3.1 3.1 3.4 3.0

–

ns

Green manure as N source for flooded rice B. Singh, Y. Singh, M. S. Maskina, and O. P. Meelu, Soils Department, Punjab Agricultural University, Ludhiana 141004, India

N content and rate of mineralization determine the efficiency of a green manure. Leguminous crops used as green manure differ in both respects. We evaluated Sesbania aculeata, sunn hemp ( Crotalaria juncea ), cowpea ( Vigna

unguiculata ), and cluster bean ( Cyamopsis tetragonoloba ) as green manure for flooded rice.

Soil was a sandy loam, with pH 8.2, 0.34% organic C, and 0.06% total N. A basal dose of 26 kg P/ ha as single superphosphate and 25 kg K/ ha as muriate of potash was applied before the last puddling.

Green manure crops were incorporated at 60 d, 1 d before transplanting long-duration rice variety PR106 at 15- × 20-cm spacing.

Effect of rice planting method on azolla growth, in relation to water temperature and light intensity. Pattambi, Kerala, India, 1981 dry season.

Line plantings with two spacing combinations and two directions of lines were compared with equidistant planting (bulk method) to assure equal plant populations per unit area. Azolla was inoculated at 100 g/m 2 1 wk after planting rice; azolla yield was measured 3 wk after inoculation.

bulk rice planting method (see table). That method registered the highest light interception and lowest water temperature (see figure). Planting method did not influence rice grain and straw yields.

Azolla growth was maximum with the

For information on ordering IRRI publications, write Communication and Publications Dept., Div. R, IRRI, P. O. Box 933, Manila, Philippines. Influence of N through green manure on grain yield. N uptake, and apparent N recovery by rice,

Ludhiana, India. Bars having a common letter are not significantly different.

IRRN 13:4 (August 1988) 25

No N fertilizer was applied to green manure plots; 2 treatments received urea applied at 60 and 120 kg N/ha and 1 treatment received no N. N supplied by the green manures was adjusted on a dry weight basis. Sesbania and sunn hemp were evaluated at two N levels.

Mineralization of fresh and dry azolla in the tropics

D. Alexander, Regional Agricultural Research Station (RARS), Pattambi, Kerala; and N. Sadanandan, Directorate of Postgraduate Studies, Vellanikkara; and K. Karunakaran, RARS, Kerala, India

We studied rate of mineralization of fresh and dry azolla under tropical conditions in two pot culture experiments in Jun and Sep 1984. The experiment was laid out in circular 0.1 m 2 cement pots. Each pot contained 20 kg air-dried soil; a 5-cm water level was maintained. Organic fertilizers were incorporated and thoroughly mixed with the soil (see table).

2-wk intervals to week 12, and ammoniacal and nitrate N contents estimated and expressed as mineralized

Soil and water samples were taken at

Parthenium as green manure for rice

S. Purushothaman, S. Jeyaraman, and P. Sudhakar, Agronomy Department, Agricultural College and Research Institute, Tamil Nadu Agricultural University, Madurai 625104, Tamil Nadu, India

We compared urea, wet leucaena, dry leucaena, parthenium, and sunn hemp in the main and succeeding irrigated lowland rice crops during 1984-85 wet and dry seasons.

randomized block design with three replications. No fertilizer was applied to the second rice crop.

Grain quality characteristics—optimal cooking time, swelling rate, gruel loss,

Treatments to the main crop were in a

26 IRRN 13:4 (August 1988)

Treatments were laid out in a from green manure incorporated in randomized block design with three amounts comparable to the N supplied replications. Plant samples collected at by urea equaled or surpassed yields harvest were analyzed for total N. from urea. Cowpea and sunn hemp were

Rice responded linearly up to 120 kg the most efficient N sources, followed by N/ha applied as urea (see figure). Yields sesbania and mungbean.

Effect of organic manure and time of incorporation (2, 4, 6, 8, 10, 12 wk after incorporation) on percentage of mineralizable N. Kerala, India, 1984.

Mineralizable nitrogen (%)

2 4 6 8 10 12 Organic manure

5 t azolla/ha (13.4 kg N) 34.1 63.0 76.0 84.6 86.3 76.6 10 t azolla/ha (26.8 kg N) 26.0 43.6 40.7 47.7 57.8 61.2 Dry azolla equal to 5 t azolla/ha (13.4 kg N) 37.0 50.1 63.0 78.0 39.5 64.3 Dry azolla equal to 10 t azolla/ha (26.8 kg N) 33.3 35.6 50.5 44.9 20.5 35.6 5 t cattle manure/ha (26.9 kg N) 19.1 35.0 59.6 53.4 39.0 58.3 Green leaves of venga Pterocarpus marsupium 43.9 73.5 67.2 22.8 38.4 86.0

at 5 t/ha (25.4 kg N)

N. Percentages of available N to the quantity of N initially added were estimated by subtracting the N value of control from all treatments.

azolla/ha compared with cattle manure and green leaves from week 6 to week 8. At that level, the highest available N was

N release from 5 t fresh and dry

86.6% from fresh azolla at week 6, 78.9% from dry azolla at week 8, 59.6% from cattle manure at week 6, and 86% from green leaves at week 12. In both fresh and dry azolla, 10 t/ha reduced and prolonged N release more than did 5 t/ha. At both levels, fresh azolla was slightly superior to dry azolla.

elongation rate, and palatability (color, Using parthenium as green manure smell, and taste)-were tested in both had no effect on cooking and main and second crops. palatability characteristics.

Physiology and plant nutrition

Supply and uptake of urea- 15 N by rice

applied to rice grown under permanent flooding.

The soil was a Crowley silt loam W. Lu, C. W. Lindau, and W. H. Patrick, (Typic Albaqualf), 11% clay and 71% Jr., Laboratory for Wetland Soils and silt, with 7.0 g total C/kg, 0.8 g total Sediments, Louisiana State University, N/ kg, a cation exchange capacity of Baton Rouge, Louisiana 70803-7511, USA 9.4 meq/100 g soil; pH of 5.7 (1.1

We studied the behavior of soil, Air-dried soil (2.2 kg) ground to pass fertilizer, and plant N in a greenhouse through a 1-mm mesh sieve was placed pot experiment where urea- 15 N was in polyvinyl chloride (PVC) pots (20 cm

soil/ water ratio).

15

Treatment yield

Effect of PU and LGU on yield and N efficiency. Bhubaneswar, Orissa, India, 1986 dry season.

Time of N application Yield N uptake Total Apparent Yield N level (kg/ha)

(kg/ha) (t/ha) (kg/ha) N N response uptake recovery (kg grain/

TP 7 DT 15 DT PI Grain Straw Grain Straw (kg/ha) (%) kg N)

0 30 (PU) 60 (PU) 90 (PU) 30 (LGU) 30 (LGU) 60 (LGU) 60 (LGU) 90 (LGU) 90 (LGU)

– 20 15 22.5 20 –

15 –

22.5 –

LSD (0.05) 0.2 0.3 3.3 2.5

– –

– –

20 –

40 –

60

– – 30 45 – – 30 – 45 –

– 10 15 22.5 10 10 15 20 22.5 30

2.2 2.7 3.1 3.5 3.0 3.0 3.3 3.7 3.9 4.4

2.6 3.0 3.5 3.6 3.4 3.3 3.5 3.4 4.1 4.7

20.0 25.3 31.8 34.1 26.9 28.9 29.0 37.7 37.5 42.3

11.7 17.2 20.9 22.9 21.1 18.3 17.9 24.3 23.8 28.7

31.7 42.5 52.7 57.0 48.0 47.2 46.9 62.0 61.3 71.0

- 36.0 35.0 28.1 54.3 51.7 25.3 50.5 32.9 43.7

- 16.7 15.0 14.4 26.7 26.7 18.3 25.0 18.9 24.4

S. K. Sahu, S. K. Pattanayak, S. K. Nanda, and G. N. Mitra, Soils and Agricultural Chemistry Department, College of Agriculture, Orissa University of Agriculture and Technology, Bhubaneswar 751003, India

Comparison of prilled urea (PU) and large granule urea (LGU) and time of application on rice yield

long and 15 cm internal diameter). Deionized H 2 O containing 0.15 g P/kg soil and 0.20 g K/kg soil was added to establish water depth of 2-4 cm.

Three 20-d-old Lemont seedlings previously grown in a sand culture were transplanted into each of 20 pots. Four N treatments were applied using urea- 15 N (29.991 atom %) at 0.44 g urea N/pot. Urea- 15 N solutions were injected into the rice root zone. Each N treatment, including control, was replicated four times.

At harvest, each pot was destructively sampled and total Kjeldahl N and 15 N content determined on soil and plant components (roots, shoots, grain).

Plant recovery of applied urea- 15 N was from 58% in the roots, 10-15% in

the shoots, and 22-29% in the grain (Table 1). Total plant 15 N recovery was 38-51%; highest recovery was with treatment 3. Control grain yields were significantly different from those of the N treatments.

About 60% of the 15 N taken up by the rice plant was in the grain. 15 N remaining in the soil after harvest ranged from 14 to 24%. About 34% of the 15 N applied was unaccounted for.

The two sources of N to rice are soil N (% NdfS) and fertilizer N (% NdfF). In treatment 1, plant N was 69% NdfS and 31% NdfF; in treatment 2, 65% NdfS and 35% NdfF; in treatment 3, 67% NdfS and 33% NdfF; and in treatment 4, 64% NdfS and 36% NdfF. Rice uptake of fertilizer N was significantly correlated with grain yield ( r = 0.634**).

Percentage of NdfF in the root, shoot, and panicle rice tissues is shown in Table 2. Panicle NdfF accounted for 33- 39% of the total panicle N content, slightly higher than the 32-38% NdfF taken up by the rice shoots. NdfF was lowest in the root tissues.

Table 1. Recovery of 15 N -urea and yield of Lemont rice. a Louisiana, USA.

Treatment (% applied urea) N recovery (%) Grain

no. Transplanting Tillering Panicle Milk Soil Roots Shoots Grain (g/pot) initiation stage

1 100 – – – 21 5 10 22 26.2 2 50 30 10 10 14 5 15 28 26.7 3 50 10 30 10 24 8 4

14 29 28.7 25 25 25 25 16 7 14 29 27.2

C – – – – – – – 16.1

LSD (0.05) ns 2 ns ns 3.1

a Mean of 4 observations. C = control, no N applied.

Table 2. N derived from fertilizer in rice plant components. Louisiana, USA.

Treatment no.

N derived from fertilizer a (%)

Roots Shoots Panicles

1 22 32 33 2 22 37 37 3 30 34 35 4 27 38 39

a Mean of 4 observations.

Soil fertility and fertilizer management

15.7 kg available P/ ha (NaHCO 3 extract), and 110 kg K/ha (ammonium acetate extract).

Seedlings of Lalat (130 d duration) were transplanted on 18 Jan. All plots received 13.2 kg P. 24.9 kg K/ha at transplanting (TP).

Grain and straw yields and N uptake were significantly higher with 90 kg N/ ha from LGU applied 2/3 at 7 d after transplanting (DT) and 1/3 at panicle initiation (PI). Apparent N recovery and yield response (kg grain/ kg N) were highest at 30 kg N/ ha from LGU applied 2/3 at TP, 1/3 at PI (see table).

We compared PU (26-30 mg) and LGU (6-8 mm diameter) at 30, 60, and 90 kg N/ ha broadcast in saturated soil at 4 rice growth stages in a 1986 dry season field experiment. The 10 treatments (including no N) were in a randomized block design with 3 replications.

Soil was sandy loam (Aeric Haplaquept) with pH 5.2, 0.47% organic C, CEC 5.7 meq/ 100 g, 290 kg available N/ha (alkaline permanganate method),

IRRN 13:4 (August 1988) 27

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1 2 2 2 2 2 2 12

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the shoots, and 22-29% in the grain

N management for late transplanting in northwestern India

H. Om, D. Singh, O. P. Singh, and R. K. Joon, Haryana Agricultural University, Rice Research Station, Kaul 132021, Haryana, India

Transplanting in this region often is delayed to the end of Jul when monsoon rains are late. Different N rates and time of application are necessary in this situation.

We studied 3 rates of N (90, 120, and 150 kg/ha) applied in 4 ways in a split- plot design with 3 replications.

loam with 210 kg available N, 20.5 kg available P, and 225 kg available K/ha, EC 0.21 dS/m, 0.40% organic C, CEC 12.1 meq/100 g soil, and pH 7.8. P-K- Zn was applied at 26-50-6 kg/ha.

Seedlings of PR106 (60-d-old) and Pusa 33 (30-d-old) were transplanted 20 Jul in 1983 and 1984.

Soil of the experimental field was clay

Direct and residual effects of biogas residue application with nitrogen on rice yield

S. K. Sahu and S. K. Nanda, Soils and Agricultural Chemistry Department, Orissa University of Agriculture and Technology, Bhubaneswar 751003, Orissa, India

Organic residues from biogas plants are rich sources of N. We studied direct and residual effects of biogas residue with N on rice yields of two rice - rice cropping sequences 1984-85 and 1985-86. The second wet season trial was laid out at a different site, but very close to the first trial site. Soil of the experimental sites was sandy loam (Haplaquept) with pH 5.3, 0.77% organic matter, CEC 11 meq/100 g soil, and 260-10-165 kg available N-P-K/ha.

Treatments were with and without biogas residue and 20, 40, and 60 kg N as urea/ha distributed equally at 1, 2, or 3 growth stages, in a randomized block design replicated 3 times. The biogas residue containing 1.11% N, 0.174% P,

28 IRRN 13:4 (August 1988)

Effect of N rate on grain and straw yields of late-planted wet season rice. Kaul, India, 1983-84.

Grain yield (t/ha) Straw yield (t/ha)

1983 1984 Mean 1983 1984 Mean Treatment

Variety PR 106 Pusa 33

LSD (0.05)

90 120 150

N rate (kg/ha)

LSD (0.05) Application method a

All basal ½ basal + ½ 21 DT ½ basal + ¼ 21 DT

+ ¼ 42 DT 1/3 basal + 1/3 21

DT + 1/3 42 DT

LSD (0.05)

5.8 5.2 0.3

4.9 5 .7 6.2 0.3

5.2 5.5 5.6

5.5

0.1

4.6 4.3 0.1

4.0 4.4 4.8 0.3

4.2 4.6

4.5

–

0.1

5.2 4.7 –

4.4 5.0 5.5 –

5.2 4.8 5.1

5.0

–

1.7 5.1

0.9

5.4 6.3 6.9 0.4

6.2 6.8 6.6

6.0

0.4

6.0 4.6

0.2

5.0 5.3 5.5 0.1

– 5.6 5.3

5.0

0.1

6.8 4.9 –

5.3 5.8 6.2 –

6.2 6.2 5.9

5.5

–

a DT = days after transplanting.

Duration was 147 d for PR106 and both years (see table). Yield increased 113 d for Pusa 33 in 1983, and 148 d for significantly up to 150 kg N/ ha. Split N PR106 and 115 d for Pusa 33 in 1984. application was superior to basal PR106 had higher yields than Pusa 33 in application.

Direct and residual effect of biogas residue fertilizer with different levels of urea on rice yield. Bhu- baneswar, India, 1984-86.

Grain yield (t/ha) Treatment

BGR a + N application (kg/ha)

t/ha TP b + DT c + PI d

0 0 0 0 0 20 20 20 5 0 0 0 5 20 20 20 5 0 20 20 5 0 20 0 5 0 0 20

Direct effect (wet season) Residual effect (dry season)

1984 1985 Mean 1984-85 1985-86 Mean

2.9 2.3 2.6 2.5 1.7 2.1 3.3 3.1 3.2 3.8 3.1 3.4 3.5 3.1 3.3 2.8 2.4 2.6 3.4 2.9 3.1 3.9 3.3 3.6 3.4 2.8 3.1 3.3 2.6 2.9 3.3 2.9 3.1 3.7 2.5 3.1 3.7 2.9 3.3 2.6 2.2 2.4

CV (%) LSD (0.05)

1.3 9.4 7.7 18.4 21.2 18.8 0.3 0.4 0.3 0.7 0.5 0.4

a Biogas residue applied in wet seasons only. b At transplanting. c Days after transplanting. d Panicle initiation.

0.487% K, and 25% organic C on oven- In the wet season, fresh biogas residue dry basis was applied with 25% moisture at 5 t/ha without supplemental N at 5 t/ha to both wet season trials. The produced the maximum yield (see table) residual effect was studied in the In the dry season, 60 kg N/ha in following dry seasons. Both direct and equal applications in plots treated with residual trials also received 13 kg P and biogas residue plus 60 kg N/ha in the 25 kg K/ha, including the contribution wet season produced the maximum from biogas residue. yield.

Daya in the dry season. yield among the plots. Jajati was planted in the wet season, There was a large variation in grain

Effect of azolla green manure on rice yield G. Rakotonaivo, Université de Madagascar, Service Botanique, B. P. 906, Antananarivo, R. D. Madagascar; and M. Schramm, Humboldt-University of Berlin, Biology Department, Berlin 104, German Democratic Republic

We have studied azolla as a green manure in farmers’ fields at Antananarivo (1,260 m altitude), comparing incorporated azolla (10 t fresh weight/ha) with 30 kg and 60 kg N as urea/ha and with a split 5 t fresh weight azolla/ha + 30 kg N as urea/ ha. Azolla and urea were incorporated 1 wk before transplanting. The 10 t fresh azolla/ha was the equivalent of 26 kg N/ha.

Green manure to sustain productivity and save nitrogen for rice in a rice - wheat cropping system

J. S. Kolar and H. S. Grewal, Agronomy Department, Punjab Agricultural University, Ludhiana 141004, India

We studied the effects of 3 green manure crops— Sesbania esculentus (janter), Vigna sinensis (cowpea), and Crotalaria juncea (sunn hemp)—at 3 ages of incorporation (40-, 50-, and 60d-old crops), with 60, 90, and 120 kg N/ha on yield of rice grown after wheat.

Soil was sandy loam (Typic Ustochrept) with pH 8.1, 0.32% organic C, and 14 kg Olsen’s P/ha. Green manure crops were incorporated 1 d before transplanting rice. All plots received 13 kg P/ha and 24 kg K/ha at transplanting.

Burying sesbania, cowpea, and sunn hemp resulted in significantly higher rice productivity (Table 1). All green manure crops saved 60 kg N/ha (Table 2).


Grain and straw yields with azolla and with urea. Antananarivo, Madagascar.

Grain yield Straw yield

t/ha Increase (%) t/ha Increase (%) over control over control

Treatment

No fertilizer 5.8 – 18.6 10 t azolla 7.4 29 23.2 25 5 t azolla + 30 kg N as urea 6.7 16 19.0 2

30 kg N (urea) 6.1 6 20.2 9 60 kg N (urea) 7.8 36 24.5 32

–

LSD (0.05) 0.6 2.3

The trial was laid out in a randomized complete block design with three replications. The azolla was the indigenous Azolla pinnata var. africana, the rice variety Rojofotsy 1285.

Soil was a sandy loam mineral hydromorph with pH 5.2, 1.13% total P, 0.155% P Olsen, 3% organic matter,

1.7% C, 0.18 meq exchangeable K/100 g.

straw yields (see table). Yield was highest with 60 kg N as urea/ha, followed by that with 10 t fresh weight azolla/ha. Azolla + urea was better than urea alone.

N and azolla increased both grain and

Table 1. Grain yield of rice with green manure. Ludhiana, India, 1985-87.

Treatment Grain yield (t/ha)

1985 1986 1987 Mean

Fallow Sesbania 40 d

50 d 60 d

Cowpea 40 d 50 d 60 d

Sunn hemp 40 d 50 d 60 d

LSD (P = 0.05)

6.8 7.6 7.8 7.7 8.1 7.9 7.7 7.8 8.0 8.1 0.8

8.1 9.6 9.7 9.7

10.3 9.6 9.6 9.6 9.7 9.7 0.7

6.1 7.8 7.9 7.8 7.8 7.9 7.8 7.7 7.7 7.8 0.8

7.0 8.3 8.5 8.4 8.7 8.4 8.4 8.3 8.5 8.5 0.8

Table 2. Interaction between green manure crops, stages, and N levels on rice yields. a Ludhiana, India, 1985-87.

Grain yield (t/ha)

60 kg N/ha 90 kg N/ha 120 kg N/ha Mean Treatment

Fallow Sesbania 40 d

50 d 60 d

Cowpea 40 d 50 d 60 d

Sunn hemp 40 d 50 d 60 d

Mean

5.8 8.1 8.4 8.4

8.6 8.4 8.4

8.2 8.3 8.4

8.1

7.2 8.4 8.6 8.6 8.8 8.4 8.4 8.3 8.5 8.5 8.4

8.0 8.5 8.4 8.3 8.7 8.5 8.2 8.4 8.6 8.7 8.4

7.0 8.3 8.5 8.4 8.7 8.4 8.4 8.3 8.5 8.5

a Mean of 3 yr, 1985-87. LSD (P = 0.05) for green manure crops and stages × N levels = 0.81.

IRRN 13:4 (August 1988) 29

Crop management

Low-tillage broadcast rice productivity

Zhao Luman, Hunan Soil and Fertilizer Research Institute, Hunan Academy of Agricultural Sciences, Changsha, China

Rice - rice - green manure is a primary cropping pattern in Hunan Province. In general, a field must be plowed and harrowed several times a year. That destroys the soil structure, results in poorer soil aeration, demands more labor, and risks seedling damage from low temperature in May or high temperature in Jul.

To maintain soil productivity and high rice yields, we developed a minimum tillage and broadcast sowing rice cultivation method. Experiments to study the economic benefits and effects on soil structure between the new

method and conventional transplanting began in 1983.

Our results show that the new method has a significant effect on rice yield and economic return (Table 1, 2).

Table 2. Rice benefits from 2 cultivation methods. Changsha, China, 1986.

Treatment Rice Yie1d value a

Net Income Labor Income/ Income

(t/ha) ($/ha) ($/ha) income increase days/ha labor increase

($/ha) (%) day ($) (%)

Low tillage, Apr - Oct 13.9 1450.46 535.93 914.87 30.16 233 3.94 90 broadcast

Output Cost

season

Transplanted Apr - Oct 11.8 1235.19 532.30 702.89 – 339 2.07 – Low tillage, Jun - Oct 8.5 885.12 261.20 623.92 30.76 120 5.20 96 broadcast Transplanted Jun - Oct 7.3 760.76 283.62 477.14 – 180 2.65 –

a Rice price US$104.50/t (local government price). Exchange rate: US$l00 = 371.27 yuan RMB.

Table 1. Rice yield from 2 cultivation methods. Changsha, China, 1984-87.

Yield (t/ha) Location Cropping pattern Season Rice variety Yield increase

Low tillage Transplanted (%) broadcast

Changsha Nan County

Changsha Changsha Nan County

Changsha

Changsha Changsha

Green manure - rice

Fallow - rice

Green manure - rice Green manure - rice - rice Green manure - rice - rice

Green manure - rice

Green manure - rice

Barley - rice

Apr a - Jul

Apr - JuI

Apr - Jul Apr b - Oct Apr - Oct

Apr - Jul

Apr - Jul Apr - Jul

1984 Zhefur 802

78-1000 1985

Xiangzhao xieng 3 Zhefu 802-V35 Zhaoyun fong-V35

2106 1986

1987 V35 V35

6.8 7.3

6.2 14.4 13.7

5.6

6.3 6.6

5.9

6 .0

15.2 22

5.8 7 13.8 5 12.3 11

5.4 4

4.8 6.2

32 5

a One crop season. b Two crop seasons.

Disease management

Host plants of rice tungro (RTV)-associated viruses

A. Anjaneyulu, R. D. Daquioag, Ma. E. Mesina, H. Hibino, H. T. Lubigan, and K. Moody, IRRI

In previous studies on RTV hosts, inoculated weed plants were indexed on the basis of infection and by testing

transmission of infection from weeds to rice by the vector green leafhopper (GLH) Nephotettix virescens. Results were contradictory.

first, young seedlings of 5 Oryza spp. and 19 weed species were inoculated separately by exposing each seedling for 1 d to 10 GLH that had fed for 4 d on plants infected with both rice tungro bacilliform (RTRV) and spherical (RTSV) viruses. In the second treatment, seedlings of 4 Oryza spp. and 19 weed species were inoculated with

This study had two treatments. In the

GLH that had fed on RTSV-infected plants.

indexed by ELISA for the presence of RTBV and RTSV. Extracts of inoculated plants having absorbance at 405 nm 3 times higher than that of uninoculated plant extracts were considered to contain virus.

When seedlings were inoculated by GLH that had fed on plants infected with RTBV and RTSV, all Oryza spp. except O. latifolia were infected with RTBV and RTSV (Table 1). All doubly

At 30 d after inoculation, plants were

30 IRRN 13:4 (August 1988)

Table 1. Absorbance at 405 nm in ELISA of extracts-of plants infected with RTBV and/or RTSV after inoculation by RTBV + RTSV viruliferous GLH. IRRI.

RTBV RTSV

Inoculated Infected Absorbance at Infected Absorbance at Species plants plants 405 nm plants 405 nm

(no.) (no.) (no.) Infected Unin- Infected Unin- plants oculated plants oculated

plants plants

Oryza australiensis Acc. 100882 8 4 0.98-1.95 0.00 0 – 0.00 Acc. 101397 12 2 1.20-1.51 0.18 1 0.07 0.00 Acc. 101144 7 4 0.50-1.48 0.00 0 – 0.00

Acc. 100122 8 8 0.20-0.44 0.00 8 0.48-1.39 0.00 Acc. 100921 5 5 0.15-0.40 0.00 3 1.01-1.11 0.02

O. latifolia 10 2 0.25-0.48 0.00 0 – 0.02 O. longistaminata 10 9 0.57-1.51 0.14 4 0.34-0.89 0.00 Axonopus compressus 12 0 – 0.01 5 0.18-0.46 0.00 Brachiaria mutica 8 0 – 0.02 4 0.06-0.06 0.00 Cyperus rotundus 9 1 0.20 0.05 1 0.36 0.00 Eleusine indica 12 3 0.04-0.14 0.01 0 – 0.00 Fimbristylis miliacea 12 8 0.11-1.47 0.00 1 0.36 0.00 Leersia hexandra 10 2 0.14-0.17 0.04 0 – 0.00 Monochoria vaginalis 12 1 0.33 0.10 0 – 0.11

O. barthii

Table 2. Absorbance at 405 nm in ELISA of extracts of plants infected with RTSV after inoculation by RTSV-viruliferous GLH. IRRI.

Inoculated Infected Absorbance at 405 nm

Infected Uninoculated Species plants plants

(no.) (no.) plants plants (mean)

Oryza australiensis Acc. 101144 7 5 0.11-0.29 Acc. 101397 12 3 0.09-0.14

Acc. 100117 3 3 0.89-1.11

Acc. 101196 9 4 0.12-1.82 0.05-0.09

0.08

0.03

O. barthii 0.02

O. longistaminata 0.05

Brachiaria mutica 20 3 0.03

Cynodon dactylon 22 10 0.01

Cyperus brevifolius 8 0.02

1 C. difformis 10 5

0.00

C. rotundus 12 0.13-0.54

6 0.04

Digitaria ciliaris 10 0.04-0.45 0.01

5 Echinochloa colona 12

0.10-0.15 0.00 3

Eleusine indica 0.34-0.40

12 4 0.10

Eragrostis tenella 0.04-0.12

10 5 0.01

0.18-0.37 Fimbristylis miliacea 12 5 0.10-0.35

0.05

Imperata cylindrica 10 0.00

4 Leersia hexandra 10 2

0.10

Monochoria vaginalis 0.05-0.07

11 0.00

2 0.13-0.16 0.02

0.07-0.15

0.36-0.43

infected plants showed symptoms typical the C. rotundus plants did not. of RTV. O. australiensis and O. latifolia Brachiaria mutica and Axonopus were predominantly infected with compressus were infected with only RTBV. RTSV; many other species were infected

Cyperus rotundus and Fimbristylis Weeds not infected with either virus miliacea were infected with RTBV and were Brachiaria distachya, Chloris RTSV. The doubly infected F. miliacea harbata, Cynodon dactylon, Cyperus plants showed stunting and brevifolius, C. difformis, Digitaria discoloration of newly emerged leaves, ciliaris, Echinochloa colona, Eragrostis

Among weed species tested, only predominantly with RTBV.

tenella, Imperata cylindrica, Leptochloa chinensis, Paspalidium flavidum, and Paspalum dilatatum.

Among seedlings inoculated by GLH that had fed on RTSV-infected plants, 3 of 4 Oryza spp. and 13 of 19 weed species were infected with RTSV (Table 2). None of the infected plants showed symptoms. Species not infected with RTSV were O. latifolia, Axonopus compressus, Brachiaria distachya, Chloris barbata, Leptochloa chinensis, Paspalidium flavidum, and Paspalum conjugatum.

Unrecorded weed hosts for Pyricularia oryzae Cav. in India

N. I. Singh and Kh. U. Singh, Botany and Plant Pathology Department, Manipur Agricultural College, Iroisemba, Imphal 795001, India

Many rice pathogens are reported to survive on wild weed hosts. Weeds such as Leersia hexandra, Panicum repens, Arundo donax, Brachiaria mutica, and Cyperus compressus have been reported to harbor P. oryzae in India.

In 1986-87, we studied possible weed hosts for the rice blast fungus P. oryzae in ricefields and on rice bunds. Diseased weeds collected from rice-growing areas in Imphal, Thaubal, Bishenpur, Churachandpur, and Senapati districts were brought to the laboratory and the fungus isolated on potato dextrose agar (PDA). Pathogenicity of fungus isolates was tested by spraying mycelial fragments prepared from 7-d-old culture onto each weed host and control plant.

Reaction of different isolates of P. oryzae on weeds. Manipur, India.

Disease reaction a

Weed host Isolate on no.

HR12 KD2-6-3

Leersia hexandra 1 + + Cyperus rotundus 2 + + C. compressus 3 + C. iria 4 + +

a + = infection, – = no infection.

–

IRRN 13:4 (August 1988) 31

L. hexandra, C. compressus, Cyperus rotundus, and C. iria consistently harbored P. oryzae.

To study pathogenicity on rice, we inoculated potted seedlings of highly susceptible variety HR12 and popu1ar variety KD2-6-3 at the 3- to 4-leaf stage with different isolates of P. oryzae. All isolates produced blast symptoms on HR12. The isolate from C. compressus failed to infect KD2-6-3 (see table).

Diseases of deepwater rice in Jorhat District, Assam, India

Y. Rathaiah, Regional Agricultural Research Station, Assam Agricultural University, Titabar 785630, Jorhat District, Assam, India

We surveyed 20 fields at different sites over some 6,000 ha of deepwater rice along the Brahmaputra River during rice flowering to ripening stages Oct-Dec 1987.

A general impression of disease incidence was obtained first, by walking across each sample field. A wooden quadrat 50 × 50 cm was placed at random along the field diagonal and the panicles infected with blast (Bl) among those enclosed by a quadrat counted. Ten quadrat counts were made in each field. Other diseases were recorded similarly. For ufra, the top 30 cm portions of infested stems were collected to extract the stem nematode and to count nematodes per stem.

was found at 15 sites. The disease appeared in distinct patches. On the average, 55% of the stems were infected in an ufra patch. The most common symptoms were nonemergence of panicles and half-emerged panicles.

In the most severe form of ufra, a rudimentary, skeletal panicle protruded from the boot (Fig. 1). The highest count of nematodes per stem was 7,500. Some ratoon tillers in ufra patches had chlorotic ufra symptoms: chlorosis of the youngest leaf at the neck region with brown stains on the midrib (Fig. 2). This symptom resembles a mite attack.

Ufra caused by Ditylenchus angustus

32 IRRN 13:4 (August 1988)

1. Most severe symptom of ufra — twisted ear protruding (arrow) from the boot. Assam, India, 1987.

Dominant deepwater varieties Amanabao and Rangabao were highly susceptible to ufra.

Neck Bl caused by Pyricularia oryzae was the second most important disease. On the average, 25% of the panicles in 10 infested fields were infected. Ratoon tillers from basal stem nodes were infected with leaf Bl; typical Bl spots also were observed on the flag leaves. Nodal Bl was common in several fields.

2. Chlorotic ufra symptom in ratoon tillers. Assam, India, 1987.

Amanabao and Rangabao were susceptible to neck Bl.

Other diseases found were sheath rot (less than 1% stems infected), bacterial blight (5% leaf area infected), brown spot (less than 5% leaf area infected), false smut (1% panicles infected), and kernel smut (1% panicles infected).

Host plants of ragged stunt virus (RSV)

A. Anjaneyulu, G. Z. Salamat, Jr., Ma. E. Mesina, H. Hibino, R. T. Lubigan, and K. Moody, IRRI

We inoculated young seedlings of 2 Oryza spp. and 15 weed species separately with 20 RSV-viruliferous brown planthopper Nilaparvata lugens each. Inoculated plants were indexed by ELISA 30 d after inoculation. Extracts of plants with absorbance at 405 nm

higher than 3 times that of uninoculated plant extracts were considered to contain the virus.

Both rice accessions and six weed species were infected with RSV (see table). Infected Oryza plants showed typical RSV symptoms. Infected Leersia hexandra plants also showed symptoms. Weed species not infected with the virus were Brachiaria distachya, B. mutica, Chloris barbata, Cyperus brevifolius, C. difformis, Eleusine indica, Imperata cylindrica, Leptochloa chinensis, and Paspalum conjugatum.

Absorbance at 405 nm in ELISA of extracts of plants infected with RSV after inoculation by RSV-

Species plants plants

viruliferous BPH. IRRI.

Inoculated Infected Absorbance at 405 nm

Infected Uninoculated plants plants (mean) (no.) (no.)

Oryza australiensis

Acc. 101397 O. latifolia

Acc. 100882 14 12 10

2 0.13-0.48 6 0.07-0.29 3 0.13-4.22

0.00 0.00 0.01

Axonopus compressus 12 0.15 0.04 1 Cynodon dactylon Cyperus rotundus

12 1 0.17 0.03 16 1 0.25

Eragrostis tenella 0.00

12 3 0.12-0.37 0.04 Fimbristylis miliacea 12 3 0.10-0.28 0.00 Leersia hexandra 28 5 0.06-0.12 0.00

Differential transmission of tungro (RTV) by green leafhopper (GLH) selected on IR54

A. Muis, M. Sudjak S., A. Bastian, and A. Hasanuddin, Maros Research Institute for Food Crops, P. O. Box 173, Ujung Pandang, South Sulawesi, Indonesia; and R. C. Cabunagan and H. Hibino, IRRI

We compared RTV transmission by a GLH Nephotettix virescens colony maintained since 1982 on resistant variety IR54 in the greenhouse and by a colony on TN1, using a selected set of 12 differential varieties. Seven-day-old seedlings in test tubes were inoculated separately at 1 insect/seedling for 24 h, using GLH adults that had fed on RTV- infected Pelita plants. Infection

symptoms (stunting and yellowing) were assessed visually 14 d after inoculation (DAI) and by latex serology 16 DAI.

Higher infection rates were obtained from the IR54 colony on IR28, IR29, IR34, IR50, IR54, IR58, and IR60, with resistances to GLH derived primarily from Gam Pai 30-12-15 (see figure). The latex test showed seedlings mostly were infected with both bacilliform (RTBV) and spherical (RTSV) viruses. Inoculation with the TNl colony resulted in infection mainly with RTBV alone.

Regardless of colony, IR26 and IR30 had high RTBV infection. IR36 and IR42 had high infection with both viruses.

These results indicate that GLH selected on IR54 have higher ability to transmit RTBV and RTSV on varieties with Gam Pai 30-12-15 in their parentage. Resistance of IR54 to RTV is conditioned only by its resistance to the GLH vector, not to the RTV-associated viruses.

RTV incidence based on symptoms and RTBV + RTSV incidence based on the latex test in rice varieties inoculated at 1 insect/seedling in test tubes by TN1 and IR54 GLH colonies that had fed on Cisadane plants infected with both RTBV and RTSV.

Combined ufra + blast (BI) infection in deepwater rice

Y. Rathaiah, Regional Agricultural Research Station, Titabar 785630, Jorhat District, Assam, India

Ufra disease caused by the stem nematode Ditylenchus angustus is spreading rapidly in the deepwater rice

IRRN 13:4 (August 1988) 33

cpsadmin

Line

1. Blast lesion (arrow) on the boot of an ufra- 2. Blast lesion (arrow) on the boot leaf of a half- affected stem. Assam, India. exserted panicle. Assam, India.

areas of Jorhat District, Assam. During a survey of ufra incidence, we also found B1 symptoms on ufra-infected stems.

Ufra symptoms were severe in the deepwater rice variety Kekua. The panicles failed to emerge, remaining completely choked within the boot. The swollen boot looked like a long spindle. (This type of symptom is termed swollen ufra.)

appeared on the boot leaf sheaths of Dark brown elliptical lesions

swollen ufra stems. The lesions on the boot spread linearly, reaching up to 1 cm, and were slightly sunk lengthwise to become boat-shaped (Fig. 1). The lesions turned ash gray in the center with fungus sporulation (Fig. 2). We consistently isolated the B1 fungus Pyricularia oryzae from the growing edges of the lesions.

numbers from the swollen boots that had B1 lesions. Typical B1 lesions also were present on the flag leaf and the

Stem nematode was extracted in large

34 IRRN 13:4 (August 1988)

second youngest leaf of swollen ufra stems. B1 lesions were common on the collars. Nodal Bl also was seen on many stems showing ufra symptoms.

The pathogenicity test with the fungus on detached ufra-infected stems proved B1. The unusual occurrence of Bl on the leaf sheath may be due to alteration of plant physiology caused by the ufra nematode.

Dot-blot immunoassay (DBI) for detecting rice grassy stunt virus (GSV)

P. Q. Cabauatan and H. Hibino, IRRI; and H. T. Hsu, USDA-ARS, Beltsville, Maryland, USA

We used DBI to detect GSV in extracts of infected rice plants (Oryza sativa) and compare conventional rabbit polyclonal antiserum (PAb) and mouse monoclonal antibodies (MAb).

Commercially available (Sigma) enzyme-labeled immunoglobulins (IgG) used as second antibodies were goat antimouse IgG : horseradish peroxidase (GAM IgG : HP), goat antimouse IgG : alkaline phosphatase (GAM IgG : AP), and goat antirabbit IgG : alkaline phosphatase (GAR IgG : AP). Three 1st/2d antibody combinations were tested: MAb/GAM IgG : AP, MAb/GAM IgG : HP, and PAb/GAR IgG : AP.

Leaf samples of GSV-infected plants were ground in Tris buffered saline solution [(TBS), 0.05 M Tris-HC1, 0.15 M NaCl, pH 7.5] and the extracts filtered or centrifuged to remove plant debris. A nitrocellulose membrane [(NM), 15 × 9.2 cm, pore size 0.4 µm] that had been immersed in TBS and air- dried was secured in a Bio-Dot microfiltration apparatus (Bio Rad) to align and standardize dots. A small amount (2.5-20 µl) of extract was put into each well.

The dotted NM was incubated for 60 min in a moist chamber, then immersed for 30 min in blocking solution [0.5 M TBS containing 0.05% Tween 20, 2% polyvinyl pyrrolidone (PVP), and 2% bovine serum albumin (BSA), pH 7.5].

After blotting, the NM was immersed in either PAb or MAb, diluted 500× with blocking solution, incubated for 60 min, rinsed once with distilled water and washed twice with blocking solution (10 min each with gentle shaking).

Enzyme-labeled second antibodies, diluted 2000× with conjugate buffer [(CB), 0.01 M Tris-HCl, 0.1 M NaCl, 0.0005 M MgCl 2 , pH 9.5], were incubated with each set of NM (one NM per antibody combination) for 60 min, and rinsed once with distilled water and twice with CB. For alkaline phosphatase, each set of NM was immersed in freshly prepared color development solution, each milliliter containing 0.33 mg nitro blue tetrazolium (NBT, grade III, Sigma) and 0.17 mg 5-bromo-4 chloro-3 indolyl phosphate -toluidine salt (BCIP, Sigma) and incubated in the dark for 2-4 h. For horseradish peroxidase conjugates, the blots were incubated in TBS containing 0.5 mg 4-chloro-1-naphthol/ml, 0.015% hydrogen peroxide for 15 min. Color reaction was stopped by washing each set in 0.01 M Tris-HCl containing 0.05 M EDTA, pH 7.5.

Violet color indicated the presence of GSV antigen.

MAb/GAM IgG : AP was the most effective antibody combination in detecting GSV in infected sap. Positive reactions were distinct and no detectable nonspecific reactions were seen in healthy plant extracts (see figure). High nonspecific reactions were found in the two other antibody combinations. With MAb/GAM IgG : AP, GSV was

Reaction of GSV-infected (dark spots) and healthy (open circles) sap to GSV-MAb using GAM Igc:AP as second antibody in dot-blot immunoassay.

detectable in as little as 2.5 µl sap of 10× dilution.

The principles of DBI and enzyme-

Survival of stem rot (SR) fungi

S. Sunder, D. S. Dodan, and R. Singh, Haryana Agricultural University (HAU), Rice Research Station, Kaul 132021, Kurukshetra, Haryana, India

linked immunosorbent assay (ELISA) are almost the same, but DBI assay is simpler and faster.

Rice SR caused by Sclerotium spp. like S. oryzae and S. hydrophylum is common in Haryana. It survives from season to season through sclerotia that either remain inside the stubble or get mixed in the soil. The disease appears at maximum tillering in Aug.

1. Survival of Sclerotium oryzae in laboratory and field. Haryana, India.

IRRN 13:4 (August 1988) 35

We studied SR fungi survival from Nov to Aug in the laboratory and in the field. Infected tissues of both fungi were collected from the field. One set was chopped into small pieces (intact sclerotia) and kept in the laboratory at room temperature or buried 2 cm deep in the field. In another set, sclerotia produced on rice grain-husk medium (free sclerotia) were dried in the shade and stored in laboratory or buried in the field.

Monthly collections of sclerotia were surface sterilized with 0.05% HgC1 2 , plated on 2% water-agar amended with 1,000 ppm streptopenicillin, and incubated at 28 ± 1 °C. Each treatment was run with 20 sclerotia 3 times. Sclerotial viability after 3- and 14-d incubation was recorded separately for S. hydrophylum and S. oryzae.

Under laboratory conditions, more than 55% of the sclerotia of both fungi remained viable in Aug. Under field conditions, 20% of S. oryzae sclerotia and 33% of S. hydrophylum sclerotia were viable. Intact sclerotia had higher survival than free sclerotia (Fig. 1, 2).

2. Survival of Sclerotium hydrophylum in laboratory and field. Haryana, India.

Effect of cytozyme on incidence of rice sheath blight (ShB) A. K. Roy, Regional Agricultural Research Station (RARS), Assam Agricultural University (AAU), Diphu 782460, Assam (current address: Department of Plant Pathology, AAU, Jorhat 785013, Assam, India)

Cytozyme containing a series of biologically active compounds may help increase plant growth and alter susceptibility to disease. We studied the effect of a cytozyme root dip on incidence of ShB caused by Rhizoctonia solani Kuhn [ Thanatephorus cucumeris

Table 1. Effect of cytozyme and T. viride on ShB incidence. Assam, India, 1982.

Sheaths infected Infection a

Treatment 1.5 mo after treatment (%) After 1.5 mo After 2.5 mo

Inoculation with R. solani alone 75.80 8.3 8.7 Inoculation with R. solani with 5 min 43.49 5.0 6.7

Inoculation with R. solani with 2 h 52.91 6.3 8.0

Inoculation with R. solani + T. viride 13.30 0.3 0.7

cytozyme dip

cytozyme dip

LSD (0.05) 16.37 CV (%) 18.74

a By the Standard evaluation system for rice 0-9 scale.

(Frank) Donk = T. sasakii (Shirai) Tu ex S.F. Gray, a known antagonist of R. and Kimbrough] in winter rice in 1982 solani, also was evaluated in the 1983 and 1983. The effect of cytozyme on experiment. There were four treatments, populations of Trichoderma viride Pers. each represented by four pots (Table 1).

36 IRRN 13:4 (August 1988)

Table 2. Effect of T. viride alone and with cytozyme on ShB infection. Assam, India, 1983.

Sheaths Treatment infected

(%)

Inoculation with R. solani alone 74.6 Inoculation with R. solani + T. viride 60.3 Inoculation with R. solani + T. viride 90.0

with 2 h cytozyme dip LSD (0.05) 14.5 CV (%) 12.1

Host plants of rice grassy stunt virus (GSV)

A. Anjaneyulu, V. M. Aguiero, Ma. E. Mesina, H. Hibino, R. T. Lubigan, and K. Moody, IRRI

We inoculated seedlings of 4 Oryza spp. and 18 weed species by confining separately in cages for 1 d with 20 brown planthoppers Nilaparvata lugens that had fed on plants infected with GSV strain 2. Inoculated plants were indexed by ELISA 1 mo later. Extracts of plants with absorbance at 405 nm higher than 3 times that of uninoculated plant extracts were considered to contain the virus.

All rices and five weed species were infected (see table). The infected rices showed typical GSV symptoms. None of the infected weeds showed clear

Fungicides to control rice sheath blight (ShB)

H. U. Ahmed, A. K. M. Shahjahan, and S. A. Miah, Plant Pathology Division, Bangladesh Rice Research Institute (BRRI), Joydebpur, Gazipur, Bangladesh

It has been difficult to find a good source of resistance to rice ShB caused by Rhizoctonia solani. We tested seven chemicals during transplanted aman season (Jul-Nov) 1987 on the BRRI farm. The experiment was set up in 3- × 2-m plots in a randomized complete block design with 3 replications.

Susceptible variety BR11 was transplanted at 30 d after seeding (DAS)

The root dip was prepared by mixing 2 ml cytozyme with 24 ml water. Seedling roots were dipped for 5 min and 2 h the first year and for 2 h the second year, then air-dried for 2 h. Rice variety Pusa 2-21 was transplanted 18 Aug 1982, 25 d after seeding (DAS), at 4 seedlings/pot in inoculated soil (inoculum in maize-meal sand medium added at 5% of soil). Mahsuri was transplanted on 2 Aug 1983, 25 DAS.

Although cytozyme reduced ShB infection 1.5 mo after inoculation, the difference disappeared at 2.5 mo (Table 1). ShB suppression was more pronounced with T. viride than with cytozyme. However, the effect of T. viride was not pronounced on Mahsuri in 1983 (Table 2). When T. viride was used with cytozyme, its suppressing effect was nullified.

Absorbance at 405 nm in ELISA of extracts of plants infected with GSV after inoculation by GSV- viruliferous BPH. IRRI.

Species Inoculated Infected

plants plants (no.) (no.) plants plants (mean)

Absorbance at 405 nm

Infected Uninoculated

Oryza australiensis Acc. 100882 Acc. 101144 Acc. 101397

O. barthii O. latifolia O. longistaminata Cynodon dactylon Cyperus rotundus Echinochloa colona Leersia hexandra Monochoria vaginalis

14 9 5 3

10 3

10 9

10 10 10

6 3 3 2 4 3 4 5 2 2 1

0.08–1.40 0.16–0.32 0.19–0.99 0.68–1.14 0.27–0.70 0.09–0.33 0.05–0.14 0.24–0.96 0.08–0.40 0.07–0.13 0.10

0.00 0.00 0.00 0.04 0.03 0.00 0.0 1 0.05 0.02 0.02 0.03

symptoms. Weeds not infected with indica, Eragrostis tenella, Fimbristylis GSV were Axonopus compressus, miliacea, Imperata cylindrica, Brachiaria distachya, B. mutica, Chloris Leptochloa chinensis, Paspalidium barbata, Digitaria ciliaris, Eleusine flavidum, and Paspalum conjugatum.

Effect of fungicides on ShB and rice yield. a BRRI, T. aman, 1987.

Treatment Yield at 14% Disease index moisture

Fungicide Rate/ha (t/ha)

Thiabendazole Iprodione Thiabendazole + maneb Propiconazole Thiophanate-methyl Thiophanatemethyl + thiram Edifenphos Control (inoculation, no spray)

CV (%)

1 liter 3.5 abc 1 kg 3.8 abc 2.25 kg 5.5 a 1 liter 2.0 cd 2.25 kg 2.7 bc 2.25 kg 3.2 bc 0.8 liter 4.8 ab

5.7 a 15.6

4.1 a 3.9 ab 3.7 b 4.2 a 3.4 c 3.9 ab 4.1 a 3.4 c

7.5

a Means of 3 replications. In a column, figures followed by the same letter are not significantly different at the 0.05 level (DMRT).

with 20- × 15-cm spacing. superphosphate, and muriate of potash. Recommended 60-40-40 kg NPK/ha N was topdressed in 2 equal splits at was applied, using urea, triple 21 d after transplanting (DT) and before

IRRN 13:4 (August 1988) 37

panicle initiation; P and K were applied basally.

Rice plants were inoculated at panicle initiation to booting stage by placing 21- d-old culture of fungus grown in rice straw between the tillers of each hill at water level.

Fungicides were sprayed 7 d after

Effect of N and K on rice sheath rot (ShR) and crop yield

M. Jayasekhar, Agricultural Research Station, Tamil Nadu Agricultural University, Paramakudi 623707; and N. N. Prasaid, Faculty of Agriculture, Annamalai University, Tamil Nadu, India

We applied 5 levels of K, 1 level of P, and 2 levels of N in a 15-m 2 plot for a field trial. Incidence of ShR caused by Sarocladium oryzae (Sawada) Gam. was recorded 1 wk before harvest.

Disease incidence (DI) decreased with increased K (see table). Increasing the N level but with no change in P increased DI.

Insect management

Using mixtures of buprofezin and cypermethrin or deltamethrin for green leafhopper (GLH) and rice tungro virus (RTV) control

R. F. Macatula, O. Mochida, and J. A. Litsinger, Entomology Department, IRRI

Buprofezin, a slow-acting insectistatic compound, has high activity against Nephotettix virescens nymphs and is 50 to 100 times more effective than conventional insecticides. It is slow acting. It does not kill adult insects; only nymphs die during molting to the next instar. Deltamethrin and cypermethrin, which are pyrethroids, have quick knockdown effect on GLH adults.

38 IRRN 13:4 (August 1988)

inoculation. Disease index (DI) data increases in yield (see table). were recorded at maturity, yield was Thiophanate methyl decreased disease estimated from a central 2- × 1-m incidence with no increase in yield. With sample of each plot. thiabendazole, iprodione, thiabendazole

methyl + thiram significantly reduced increased but disease did not decrease disease severity, with corresponding significantly.

Propiconazole and thiophanate + maneb, and edifenphos, yield

Rice ShR and yield in Tamil Nadu, India.

Treatment (kg/ha) of Disease Decrease Grain incidence (%) yield

N P K (%) over control (kg/plot)

75 62.5 0 45 – 4.0 75 62.5 50 37 17 4.3 75 62.5 100 26 43 4.6 75 62.5 150 17 62 4.8 75 62.5 200 11 75 5.1

125 62.5 0 50 – 4.4 125 62.5 50 42 16 4.8 125 62.5 100 31 38 4.9 125 62.5 150 21 57 5.4 125 62.5 200 16 68 5.7

LSD (P = 0.01) 3 ns

The International Rice Research Newsletter is mailed free to individuals and institutions engaged in rice research and training. For further information. write IRRI, Communication and Publications Dept., Division R. P.O. Box 933, Manila, Philippines.

Table 1. Field evaluation of buprofezin and deltamethrin for GLH control. a IRRI, 1986.

GLH (no./10 hills) c at 1 DAT Hills (no.) showing

Insecticide b Rate (g ai/ha) 1st spraying 2d spraying

RTV symptoms at 65 DT

Adult Nymph Adult Nymph

Buprofezin 25 WP + 50 + 6 1.3 ab 0.8 a 1.8 a 39.8 ab 7.5 bc deltamethrin 2.5 EC Buprofezin 25 WP + 75 + 6 1.3 ab 0.5 a 1.8 a 29.5 ab 6.9 bc deltamethrin 2.5 EC Buprofezin 25 WP + 6 + 13 1.0 ab 1.0 a 1.8 a 12.0 ab 5.0 bc deltamethrin 2.5 EC Buprofezin 25 WP + 25 + 13 1.0 ab 0.5 a 0.3 a 15.0 ab 5.4 bc deltamethrin 2.5 EC Buprofezin 25 WP + 75 + 13 1.0 ab 2.0 a 3.5 ab 8.5 a 5.0 bc deltamethrin 2.5 EC Buprofezin 25 WP 50 2.8 ab 28.8 b 3.3 ab 18.3 ab 10.8 bc Buprofezin 25 WP 75 3.8 b 24.5 ab 7.0 bc 73.5 bc 13.0 b

Deltamethrin 2.5 EC 13 0.5 a 0.3 a 2.0 a 11.3 ab 6.0 bc

BPMC 50 EC 750 3.0 ab 15.5 ab 4.3 ab 34.8 ab 12.5 b Untreated 4.0 b 20.0 ab 11.3 c 109.5 c 21.8 a

DMRT. b Insecticides were applied at 20, 35, 50, and 65 DT. Spray volume was 300-500 liters/ha. a In a column, means followed by a common letter are not significantly different at the 5% level by

c Av of 4 replications. DAT = days after treatment.

We tested 3 insecticides and their mixtures against GLH populations and RTV infection in 2 separate experiments: buprofezin (6 to 100 g ai/ha) applied alone or in combination with deltamethrin (6 to 13 g ai/ha) or cypermethrin (12.5 to 75 g ai/ha); BPMC was applied at 750 g ai/ ha for comparison.

GLH were collected by FARMCOP suction sampler from 10 hills 1 to 2 d after each insecticide application. RTV infection was recorded 65 d after transplanting (DT).

Significantly fewer GLH adults and nymphs were found on plots treated with buprofezin and deltamethrin alone or in combination (Table 1). Even at 50 + 6 g ai/ha, buprofezin- and deltamethrin-treated plots had fewer GLH. BPMC was effective on both GLH adults and nymphs. Buprofezin + deltamethrin at 6 + 13 g ai/ha was as good as higher rates against GLH and RTV.

Buprofezin- and cypermethrin-treated plots had fewer GLH at increasing rates of combination in both EC and WP formulation (Table 2). RTV infection

Orientation of whitebacked planthopper (WBPH) to scentless rice plants

G. Liu and R. M. Wilkins, Agricultural and Environmental Science Department, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, UK; and R. C. Saxena, Entomology Department, IRRI

Plant odors act as chemical messengers for insect orientation. Attractants in susceptible rice plants and repellents in resistant plants play an important role in an insect’s host selection and establishment. We studied WBPH Sogatella furcifera orientation when insects were offered rice plants wrapped in parafilm membrane.

Side tillers of 8-wk-old resistant Rathu Heenati and susceptible TN1 plants in pots were cut off. Half the remaining central tillers were left

Table 2. Effect of mixtures of an insectistatic (buprofezin) and a synthetic pyrethroid (cypermethrin) to control GLH and RTV incidence. IRRI, 1986.

GLH (no./10 hills) at 2 DAT b

Rate RTV-infected

1st spraying 2d spraying hills (%) at 65 DT

Insecticide a (g ai/ha)

Adult Nymph Adult Nymph

Buprofezin + 25 + 12.5 2.8 ab 12.8 ab 12.0 b 3.0 a 41 cd cypermethrin 10 + 5 WP Buprofezin + 50 + 25.0 0.8 ab 6.8 ab 2.8 a 4.5 a 33 abc cypermethrin 10 + 5 WP Buprofezin + 100 + 50 1.0 ab 5.0 a 1.8 a 2.3 a 24 a cypermethrin 10 + 5 WP Buprofezin + 25 + 12.5 3.8 b 19.5 b 4.3 ab 1.5 a 38 bcd cypermethrin 10 + 5 WP Buprofezin + 50 + 25.0 3.0 ab 7.0 ab 2.8 a 2.8 a 32 ab cypermethrin 10 + 5 WP Buprofezin + 100 + 50.0 1.3 ab 8.3 ab 1.3 a 0.5 a 28 a cypermethrin 10 + 5 EC Cypermethrin 5 EC 50 0.3 a 5.0 a 1.3 a 4.3 a 27 a Buprofezin 25 WP 50 4.0 bc 16.0 ab 12.0 b 2.5 a 30 ab Control 6.8 c 16.0 ab 26.8 c 40.5 b 42 d

a Insecticides were applied at 10, 30, 50, and 70 DT. Spray volume was 300-500 liters/ha. b Av of 4 replications. In a column, means followed by a common letter are not significantly different at the 5% level by DMRT. DAT = days after treatment.

was significantly lower on treated plots, Because typhoons during the except for buprofezin + cypermethrin at reproductive stage caused plants to 25 + 12.5 g ai/ha in both formulations. lodge, yield was not considered.

Orientation of macropterous S. furcifera females to parafilm-wrapped and exposed Rathu Heenati and TN1 rice plants. a

Treatment Oriented females b (%) at indicated time after release

0.5 h l h 2 h 4 h

Wrapped TN1 10 a (3)

Exposed TN1 25 b (18)

Exposed Rathu Heenati

Wrapped TN1

Wrapped Rathu Heenati 8a (3)

Wrapped TN1 10 a (4)

16 a (8) 42 b

(45) 43 a

(47) 21 b

(13) 27 a

(21) 26 b

(19)

15 a (7) 57 b

(71) 56 a

(69) 18 b

(10) 32 a

34 a (31)

(31)

15 a (7) 58 b

(71) 50 a

(59) 18 b

(10) 39 a

40 a (40)

(41)

a In a column within a pair, means followed by a common letter are not significantly different at P=0.05 (DMRT). b Arc sine percentage transformed value. Mean of 5 replications. Figures in parentheses represent actual percentage of females oriented.

exposed and half wrapped with a 5- × were inserted into 15- × 30-cm 30-cm piece of stretched parafilm (a cylindrical mylar cages through small waterproof, thermoplastic sealing film). holes in the polystyrene disc that was the Pairs of exposed and wrapped tillers common base for the plants.

IRRN 13:4 (August 1988) 39

Newly emerged macropterous WBPH females were released, 20/polystyrene disc. The females were allowed free choice between parafilm-wrapped TN1 and exposed TN1; exposed Rathu Heenati and parafilm-wrapped TN1; and parafilm-wrapped Rathu Heenati

and wrapped TN1, with five replications each treatment. Females settling on each tiller were counted at 0.5, 1, 2, and 4 h after release.

WBPH females clearly preferred exposed TN1 over parafilm-wrapped

TN1 plants (see table). Significantly more WBPH settled on exposed resistant Rathu Heenati than on wrapped susceptible TN1. WBPH were oriented nearly equally to wrapped Rathu Heenati and TN1 plants.

Minimal dosages of buprofezin to control green leafhopper (GLH), whitebacked planthopper (WBPH), and brown planthopper (BPH)

R. F. Macatula, O. Mochida, and J. A. Litsinger, Entomology Department, IRRI

Buprofezin, a slow-acting insectistatic compound, has high activity against nymphs of planthoppers, leafhoppers, whiteflies, and mites. It has no knockdown action; most nymphs die during molting to the next instar. While buprofezin does not kill adult insects, it suppresses egg deposition and egg viability to reduce populations of nymphs and adults in the next generation.

In two experiments, we tested minimum rates of buprofezin for leafhopper and planthopper control.

at 12.5, 25, and 50 g ai/ha. BPMC and cartap were applied at 750 and 1,000 g ai/ ha, respectively, for comparison.

IR22 seedlings raised under netting were transplanted 21 d after sowing in 5- × 4-m plots (Aug 1985) and 5- × 5.3-m plots (Nov 1985) at 25- × 25cm spacing with 4 replications. Insecticides (300-500 liters/ ha) were sprayed 62 d after transplanting (DT). GLH, BPH, and WBPH adult or nymph populations were sampled using FARMCOP suction machine on 10 hills/plot 1 d before treatment (DBT) and 5-15 d after treatment (DAT).

GLH, and BPH adults and nymphs

In both trials, buprofezin was applied

In general, significantly fewer WBPH,

Field evaluation of minimal dosages of buprofezin to control GLH, BPH, and WBPH. IRRI, 1985.

Rate Nymphs b (no./10 hills)

1 DBT 5 DAT 10 DAT 15 DAT Chemical a

(g ai/ha)

Buprofezin

BPMC Cartap No chemical (check)

Buprofezin


Buprofezin


12.5 25 50

750 1000

–

12.5 25 50

750 1000

–

12.5 25 50

750 1000 –

17105 a 24774 a 16142 a 21899 a 15053 a 15356 a

812 a 1092 a 508 a 995 a 227 a 987 a

103 a 122 a 107 a 107 a 133 a 121 a

BPH 1413 ab 737 ab 377 a

1146 ab 1967 ab 3324 bc

WBPH

12 ab 5 a

3 a 11 ab 26 bc 32 c

GLH 9 ab 7 a 1 a l a

15 bc 23 c

137 c 11 a

3 a 65 ab 55 ab

257 c

1 a 0 a 0 a 4 bc 8 c 1 a

6 bc 0 a 1 a 3 bc 7 bc

10 c

6 ab 4 a 1 a

14 bc 16 c 10 c

24 bc 17 bc

3 a 48 c 28 bc 40 bc

1 a 0 a 0 a 0 a 1 a 1 a

cations. In a column for each insect, means followed by a common letter are not significantly differ- a Chemicals applied by knapsack sprayer once at 62 DT. Spray volume = 500 liters/ha. b Av of 4 repli-

ent at the 5% level by DMRT.

40 IRRN 13:4(August 1988)

were found on plots treated with buprofezin, BPMC, and cartap (see table). Hopper populations were less with increasing rates of buprofezin in both trials. Buprofezin at 12.5 g ai/ha was as good as higher rates against WBPH, GLH, and BPH nymphs, and comparable to BPMC and cartap at 750 and 1,000 g ai/ha, respectively.

Predation by sword-tailed cricket Anaxipha longipennis (Serville) (Gryllidae) on eggs of three lepidopterous pests of rice

B. L. Canapi, E. G. Rubia, J. A. Litsinger, B. M. Shepard, and L. M. Rueda, IRRI

We studied the predatory ability of Anaxipha longipennis (S.) on eggs of leaffolder (LF) Cnaphalocrocis medinalis, green hairy caterpillar Rivula atimeta, and green horned caterpillar Melanitis leda ismene in the laboratory. Adults of the insect pests collected in the field were caged individually with 35-d-

Cumulative number of eggs of LF, green hairy caterpillar, and green horned caterpillar consumed by the cricket Anaxipha longipennis. a

IRRI insectary, 1988.

Eggs consumed Egg (cumulative no.)

Insect species density (no./cage) 24 h 48 h 72 h

Leaffolder

Green hairy caterpillar

Green horned caterpillar

10 20 40 10 20 40 10 20 40

8 15 34 10 16 34

2 4 6

10 18 40 10 19 39

2.0 5

10

10 19 40 10 19 40

4 5

11

a AV of 5 replications.

old TN1 rice plants for 24 h oviposition, in 5 replications. Number of eggs was adjusted to test 10, 20, or 40 per plant. A. longipennis starved for 24 h were introduced individually into the cages. The number of eggs consumed was recorded daily for 3 d.

A. longipennis preferred eggs of LF

and green hairy caterpillar (see table). By the second day, the crickets had consumed almost all the eggs of the LF and green hairy caterpillar but ate only about one-fourth of the green horned caterpillar eggs by the third day. In general, predation on LF and hairy caterpillar eggs was about three times

higher than predation on green horned caterpillar eggs. (The eggs of green horned caterpillar are larger than those of the other species tested.)

longipennis is capable of making a significant impact on eggs of two species of rice pests.

These results show that A.

Effect of insecticide application at different growth stages on rice yield components and rice straw

H. V. Pandya, A. H. Shah, and M. S. Purohit, Entomology Department, N. M. College of Agriculture, Gujarat Agricultural University, Navsari Campus, Navsari 396450, Gujarat State, India

The field experiment with 10 treatments (see table) was laid out in a randomized block design with 4 replications during summer and wet seasons 1986. Yellow

stem borer (YSB) and leaf roller (LR) were the dominant insect pests during the study. Deadhearts and whiteheads percentages were recorded for YSB and percentage of infested leaves for LR.

Grains from 10 individual selected panicles were counted at maturity and 1,000-grain wt determined separately for each treatment. Grain yield was recorded from the net plot area, straw yield was recorded separately for each treatment. Straw yield loss (t/ ha and %) was determined by deducting yield with treatment from yield with maximum

protection. Insecticide significantly influenced

pest incidence, rice yield components, and straw yield. The plot with maximum protection had the lowest % deadhearts, whiteheads, and LR infested leaves, with correspondingly higher grains/ panicle, 1,000-grain weight, grain yield, and straw yield. Maximum protection except at ripening had the lowest straw yield loss. Increased yields appear to be due to suppression of insect pests, not to fertilizer effects of carbofuran.

Yield components and straw yield of rice with insecticide applications at different growth stages. a Navsari, India, 1986 summer and wet season.

Treatment b Deadhearts Whiteheads Leaves infested Grains 1000-grain Grain Straw Straw loss

(t/ha) (t/ha) t/ha % (%) (%) with LR (%) (no./panicle) weight (g) yield yield

..

Maximum protection 3.05 2.60 2.18 289.0 (09.30) (06.76) (04.75)

Maximum protection 3.34 2.87 8.1 except seedbed

2.41 (11.16)

252.8 (08.24)

15.2 (05.81)

16.0 8.9 8.7 – –

7.8 0.9 11.5

Maximum protection except vegetative stage Maximum protection except reproductive stage Maximum protection except ripening stage Seedbed protection

Vegetative stage protection

Reproductive stage protection

Ripening stage protection

(15.76) 3.97

3.96 (15.68)

3.19 (10.18)

4.97 (24.70)

4.18 (17.47)

4.5 1 (20.34)

5.37 (28.84)

2.95 (08.70)

(09.80) 3.1 3

2.79 (07.78)

3.62 (13.10)

3.46 (11.97)

3.00 (09.00)

3.31 (11.36)

3.09 249.6 14.4 6.7 6.7 2.0 29.9

2.49 237.2 15.2 7.0 7.1 1.6 22.5

2.30 278.9 16.0 8.6 8.4 0.3 3.6

3.31 225.0 14.4 5.9 6.1 2.6 42.6

2.58 225.0 15.2 6.8 6.7 2.0 29.9

3.22 231.0 15.2 6.6 6.6 2.1 31.8

(09.55)

(06.20)

(05.29)

(10.96)

(06.66)

(10.37) 3.48

(12.11) 207.4 14.4 6.0 6.2 2.5 40.3

Control (no protection) 6.20 3.81 196.0 (38.44)

3.86 (14.52) (14.90)

13.7 5.8 5.8 2.9 50.0

LSD (0.05) CV (%)

0.54 0.03 18.90 0.86

0.24 13.02

9.0 4.5

0.6 0.9 0.4 – – 1.1 10.0 3.4 – –

a Pooled mean for 1986 summer and wet season. Figures in parentheses are retransformed values in squares. b Maximum protection = seedbed protection:

transplanting (DT), carbofuran 3 G at 1.0 kg ai/ha at 15 DT, and foliar spray of fenitrothion 50 EC at 0.05% at 35 DT; reproductive stage protection: carbofuran 3 G at 0.5 kg ai/ha 5 d before transplanting; vegetative stage protection: foliar spray of monocrotophos 36 WSC at 0.036% at 5 and 25 d after

foliar spray of monocrotophos 36 WSC at 0.036% at panicle initiation and flowering; ripening stage protection: foliar spray of monocrotophos 36 WSC at 0.036% at soft dough stage.

IRRN 13:4 (August 1988) 41

cpsadmin

Line

S. Parasuraman and A. A. Kareem, Agricultural Entomology Department, Agricultural College and Research Institute, Madurai 625104, India

We successfully reared rice LF Cnaphalocrocis medinalis Guenée (Pyraustidae: Lepidoptera) larvae using a synthetic diet. Diet constituents were 800 ml water, 70 g pinto beans, 40 g casein, 10 g agar, 5 g yeast, 5 g ascorbic acid, 2 g choline chloride, 500 mg sorbic acid, 300 mg tryptophan, and 2 ml formaldehyde 40%.

Agar and beans were cooked individually in 500 ml and 200 ml water. All other ingredients except the vitamins were mixed in a blender with 100 ml

water, then mixed with the cooked beans and agar in a blender for 4-5 mm. Two drops of Abdec (Parke-Davies) vitamin mixture were added during the last few seconds of blending. The medium, poured in small glass vials, solidified.

Second-instar larvae of LF were reared on the diet; 80% of the reared larvae pupated, from which all moths emerged. Fertility and fecundity were normal.

We evaluated the effect of six plant extracts on BPH oviposition. Seeds of Annona squamosa, Sapindus trifoliatus, Acacia concinna, Gynandropsis pentaphylla, Hydrocarpus alpina, and Ocimum gratissimum were powdered

and 1,000 g material extracted in petroleum ether (B.P. 40-60 °C) through Soxhlet apparatus. Solvent (5% benzene) was added. Stock at 2% and 5% concentrations were made by adding distilled water, using 0.5% Triton × 100 BPH oviposition (see table). No adult as the emulsifier.

Ten gravid BPH females were caged for 12 h on 40-d-old rice plants. Eggs laid were counted under a stereoscopic microscope.

All six extracts significantly reduced

BPH died during the experiment.

Population trends of striped rice borer in Korea

Y. H. Kim, K. M. Choi, and J. O. Lee, Entomology Department, Agricultural Science Institute, RDA, Suweon, Korea

Relationship between insecticide consumption and annual occurrence of 2 broods of Chilo suppressalis moths caught by light trap in 33 areas. Suweon, Korea, 1966-85.

The striped rice borer Chilo suppressalis W. has two generations in Korea. We monitored numbers of moths caught in light traps at 33 sites from 1966 to 1987. Second brood moths showed little fluctuation, but prior to 1985, the first brood progressively decreased. Relative numbers of second brood moths grew from about 20% in the late 1970s to about 60% in 1985. Populations of first brood moths, very high in the late 1960s, began to decrease in the early 1970s.

The fewest moths were captured in 1982, but populations have increased slightly since then.

The relationship between number of insects and insecticide consumption was negative before 1979. Catches of moths decreased as much as insecticide consumption increased (see figure). The population increase since 1982 might be a side effect of insecticide use.

In addition, rice transplanting has

shifted during the last two decades, from middle Jun to late May. Early transplanting may have initially contributed to low stem borer survival. The slight increase in population may represent a gradual adaptation of the stem borer to the new planting schedule.

Effect of plant extracts on brown planthopper (BPH) oviposition

G. V. P. Reddy and K. C. D. Urs, Entomology Department, University of Agricultural Sciences, Bangalore 560065, India

A synthetic diet for rice leaffolder (LF)

Eggs a (no./plant)

2% solution 5% solution

A. squamosa 13 a 9 a S. trifoliatus 68 e 62 e A. concinna 24 b 18 b H. alpina 37 c 31 c G. pentaphylla 49 d 42 d O. gratissimum 76 f 71 f Control 154 157

Effect of 6 plant extracts on BPH oviposition. Karnataka, India.

Treatment

LSD (P = 0.01) 3 3

a Mean of 5 replications. In a column, means followed by a common letter are not significantly different at the 1% level.

For information on ordering IRRI publications, write Communication and Publications Dept., Div. R, IRRI, P. O. Box 933, Manila, Philippines.

42 IRRN 13:4 (August 1988)

Water management

Irrigation schedule for dry season rice

D. Alexander and P. H. Latif, Kerala Agricultural University, Regional Agricultural Research Station, Pattambi; and S. Chandini, College of Agriculture, Vellayani, Kerala, India

In Kerala, water is scarce during the later part of dry season (Sep-Jan). We laid out an experiment during the 1982 and 1983 dry seasons to test water conservation practices. The treatments are in the table.

Soil was sandy loam (79.3% sand, 7.8% silt, and 12.9% clay) with 1.27% organic C, 0.021% available N, 11.6 kg P/ha, and 184.4 kg K/ha; pH 5.5, and bulk density 1.045 g/cm 3 . Plot size was 7.0 × 2.2 m 2 . Plots located on either side of the central irrigation channel had double bunds and 50 cm buffer strips all around. Five-cm-high pegs in the plots helped control irrigation water

Water management studies in rice

R. S. Narang and N. Singh, Agronomy Department, Punjab Agricultural University, Ludhiana 141004, India

With the advent of high-yielding, short- statured rice varieties, the area under rice in Punjab (India) has increased from 0.57 million ha in 1975 to 1.7 million ha in 1987, increasing pressure on available water resources.

with 10 cm water for 3 wk after transplanting, then apply 6-7 cm water 2 d after ponded water has infiltrated. We explored ways to reduce continuous deep flooding in 1985-87.

Rice variety PR106 was grown with three different water regimes during the rainy season (Jul-Oct) on loamy sand soil, alkaline, low-in available N, medium in available P and K. One-

Standard practice is to flood rice beds

Effect of water management practices on yield and water requirements of rice. a Pattambi, Kerala, India.

Yield (t/ha) Water Treatment b requirement

Grain Straw (cm)

Irrigations (no.)

T 1 = 5 cm submergence 3.7 4.5 92.6 33 T 2 = 5 cm submergence 3.5 4.6 63.7 11

2 d after disappearance of ponded water.

submergence for 7 d at panicle initiation and flowering.

to maximum tillering, followed by irrigation as in T 2 .

T 3 =T 2 + 5 cm 3.5 4.6 69.1 18

T 4 = 5 cm submergence 3.5 4.5 64.0 16

LSD (0.05) ns ns 12.3 8

a Av of 2-yr.

applications. and continued to 1 wk before harvest. The value of the water required for The irrigation period lasted 65 d, with

each irrigation was computed from the the groundwater table 102 cm below the head difference and time of flow. surface. Fluctuations in groundwater table were Treatment 2 had grain and straw recorded weekly from a piezometer yields equal to those from 5 cm installed in the center of the field. The continuous submergence. It consumed crop received 124.7 cm rainfall during 31% less water and required fewer growth. Irrigation treatments started irrigation. after cessation of the northeast monsoon

Effect of duration of ponded water at transplanting on growth and yield of rice at Ludhiana (Punjab), India, 1987. a

Grain Straw Plant Effective Test wt Irrigation Duration yield yield height tillers/hill (g/1000 applied

(wk) (t/ha) (t/ha) (cm) (no.) grain) (cm)

1 6.4 6.6 86.7 8.9 22.6 195 2 6.5 6.7 86.6 8.8 22.9 215 3 6.5 6.7 87.0 9.1 22.9 235

LSD (0.05) ns ns ns ns ns –

a Data pooled for 3 yr.

month-old seedlings were transplanted practice was used for later crop growth. in 8- × 3-m plots at 20- × 15-cm Reducing ponded water duration to spacing. The crop was fertilized with 1 wk at transplanting did not adversely 120 kg N, 26 kg P, 33 kg K, and 5.75 kg affect grain yield, straw yield, plant Zn/ha. Water was ponded at 40-50 mm height, effective tillers, nor 1,000-grain depths for 1, 2, or 3 wk after weight (see table). It saved 40 cm transplanting. Standard irrigation water.


cpsadmin

Text Box

IRRN 13:4 (August 1988) 43

Farm machinery

Dispenser method for using urea supergranules in transplanted rice

N. K. Savant, International Fertilizer Development Center (IFDC), P.O. Box 2040, Muscle Shoals, AL 35662, USA

Deep placement of urea supergranules (USG) by hand can be done at the same time as line transplanting by using a simple, lightweight bamboo device called a USG dispenser with transplanting guide (Fig. 1).

Two workers use 1 device to transplant two 3-m lines (Fig. 2) of 20 hills each (15- × 20-cm spacing). Quickly lifting the lever, the workers transfer USG into the wire basket (Fig.

2). Each worker picks 5 USG (Fig. 2) and hand places 1 USG at 7-10 cm soil depth in the center of alternate 4 hills (Fig. 2).

the combined operation is repeated. Some care is needed to close USG placement holes if puddling is inadequate.

Fifteen field trials have been carried out in farmers’ fields in Konkan region, Maharashtra State, India, in collaboration with Konkan Krishi Vidyapeeth, Dapoli, Maharashtra, and the Indian Farmers Fertilizer Cooperative Ltd., New belhi, India. The results indicate that the method is particularly appropriate for the small rice farmer. • It is low cost. The device can be fabricated by rural carpenters for US $4-5.

The device is pulled backwards, and

• It is simple to use. With 1-2 h practice, men and women transplanters 16-60 yr old with different education levels were able to use it. • It is labor efficient. Combining line transplanting and deep fertilizer placement saves about 12 labor d/ha that would normally have been required for separate hand deep placing of USG, • It is agronomically efficient. In 1985 and 1986 trials, grain yields with the dispenser and with separate fertilizer placement were statistically equal. In 1987 trials in small farmers’ fields, the IFDC dispenser method (15- × 20-cm spacing, 1-g USG/4 hills, 38 kg N/ha) increased grain yields an average 480 kg/ ha over farmers’ methods (random transplanting and 1 or 2 split applications of prilled urea, 38 kg N/ ha). • The method enables farmers to

1. The USG dispenser with transplanting guide, IFDC, 1986.

44 IRRN 13:4 (August 1988)

Testing a seed drill for upland rice

P. C. Senapati, P. K. Mahapatra, and D. Satpathy, Orissa University of Agriculture and Technology, Bhubaneswar, India

We tested six seed drills (Table 1) for upland rice during 1983-86 wet seasons sowing; 50% N was topdressed 20 d

in a randomized block design with three replications.

Soil was lateritic, coarse-textured, well drained, strongly acidic, and low in nutrients. Rice variety Subhadra (90 d duration) was dry seeded at 75 kg seeds/ha with 60-18-33 kg NPK/ha. All P and K and 25% N were applied at

2. Steps in using the IFDC dispenser method. IFDC. 1986. a) Workers use device for line transplanting. b) Worker transfers USG. c) Workers pick up USG. d) Workers deep-place USG by hand.

control transplanting geometry and plant populations.

The IFDC dispenser method enables small-scale rice farmers to efficiently use 30-60 kg N/ha as USG to significantly increase rice yields. It can serve as an intermediate technology for medium- scale farmers until suitable machines are developed for the effective deep placement of USG. It may not be labor efficient for large-scale rice farmers.

Table 1. Features of seed drills. Bhubaneswar, Orissa, India, 1983-86.

Drill features

Drill Width Power Seed Hopper/ Row Type of Furrow (cm) source metering drum spacing furrow openers

device capacity (cm) opener (no.) (kg)

Implement factory seed drill (3-row)

Implement factory seed-cum-fertilizer drill (2-row)

Annapurna seed drill (5-row)

Annapurna seed-cum- fertilizer drill (3-row)

CAET seed drill (3-row)

CAET seed drill (5-row)

45 Human Plastic roller with small round depressions

with small round depressions

75 Human Drum with holes on the periphery. Circular iron belt regulates the size of openings.

35 Human Drum with holes on the periphery. Circular iron belt regulates the size of openings.

roller with small round depressions mounted on the shaft

70 Bullock Wooden roller with small round depressions mounted on the shaft

30 Human Plastic roller

52 Bullock Wooden

2.5 15 Cultivator type

2.0 15 Cultivator type

4.5 15 Hoe type

2.5 15 Hoe type

6 20 Cultivator type

10 15 Cultivator type

3

2

5

3

3

5

Table 2. Efficiency of seed drills. Bhubaneswar, Orissa, India, 1983-86.

Drill Seed placement SDE Plant population

depth (no.)/row (cm) (%)

EUE

length (kg grain/MJ) CPI

Implement factory 2.85 80 25 21.83 2.70 seed drill (3-row)

Implement factory 2.87 81 28 23.03 3.33 seed-cum-fertilizer drill (2-row)

Annapurna seed drill (5-row) 1.43 65 20 Annapurna seed drill (2-row) 2.85 67

19.13 23

1.40

CAET seed drill (3-row) 3.20 12.22

77 1.46

24 CAET seed drill (5-row) 1.70 78

4.78 1.34

Broadcast 26

0.86 8.19

62 120 (per m 2 ) 3.22 1.76 0.62

IRRN 13:4 (August 1988) 45

44 IRRN 13:4 (August 1988)

after sowing (DAS) and 25% N at 40 energy use efficiency (EUE), and drill had the highest CPI (3.33), SDE DAS. comparative performance index (CPI = (81%), and number of plants/m-row

Data on average depth of seed product of energy, SDE, and grain yield (28). The three-row drill appeared to placement, seed distribution efficiency factors) are in Table 2. The two-row have had higher friction in the metering (SDE), plant population/ m-row length, implement factory seed-cum-fertilizer device.

Environmental analysis Rice response to N (kg grain produced: kg of N applied) and N recovery were highest when N was

Effect of season on rice of 4 levels of N (0, 60, 90, and applied with carbofuran or phorate (see response, production 120 kg/ ha) and 3 levels of insecticides table). efficiency, and recovery of (no insecticide, carbofuran 3% granular Across the seasons, response and N applied N at 0.75 kg ai/ ha, and phorate 10% recovery were higher in summer;

granules at 1.0 kg ai/ ha) in a production efficiency was higher in the M. A. Salam, Cropping Systems Research randomized block design with 6 northeast monsoon season. Centre, Karamana 695002, Trivandrum; and replications. S. Subramanian, Tamil Nadu Agricultural University, Coimbatore 641003, India Response, production efficiency, and recovery of N applied with and without insecticide, by season. a

We studied the response, production SWM 1982 NEM 1982 SUM 1983 SWM 1983 efficiency, and recovery of applied N in rice, with and without soil-applied granular insecticides during the

N alone 12 12 16 21 N + carbofuran at 0.75 kg ai/ha 19 20 25 22

southwest monsoon (Jun-Sep 1982), N + phorate at 1.0 kg ai/ha 20 21 26 25 northeast monsoon (Sep-Dec 1982), Production efficiency (kg grain:kg N) summer (Jan-Apr 1983), and southwest monsoon (Jan-Sep 1983). 34 12 41 56

N + phorate at 1.0 kg ai/ha 38 23 44 66

organic matter, 196-9.5-200 ppm N recovery (%)

N alone 28 17 38 34 available NPK, 598 ppm total soil N, N + carbofuran at 0.75 kg ai/ha 55 29 62 39

and 0.4 ppm DTPH extractable Zn. The N + phorate at 1.0 kg ai/ha 53 29 58 34

experiments were factorial combinations a SWM = southwest monsoon, NEM = northeast monsoon, SUM = summer.

Coimbatore, India, 1982-83.

Response (kg grain:kg N)

Soil was clay loam, pH 8.2, with 1%

Farming systems

Growth and yield of wet season rice with tilapia fish

S. K. Datta and S. H. Ghosh, Field Crop Research Station, Barddhaman; and C. N. Bairagya, Radha Fish Farm, Barddhaman, West Bengal, India

We studied growth and yield of rice and fish in the Cropping Systems Research site at Memari in 1987 (Jun-Dec) wet season. The experiment consisted of a plot of rice without fish and one of rice with tilapia ( Oreochromis mossambicus ).

Soil was clay loam with pH 6.5 - 7.0.

Plots were thoroughly plowed and 9 t farmyard manure/ ha incorporated. Plots were 20 × 38 m with a shallow 75- × 50-cm perimeter canal and a trapezoidal protective dike bounding the canal. To encourage better fish movement, 2 central drains, each 50 cm wide and 30 cm deep, were dug lengthwise across the plot of rice with fish.

Pankaj, a recommended photoperiod- sensitive lowland rice variety, was transplanted, 2 seedlings at 15- × 20-cm spacing/hill, in early Aug, with 100 kg N/ ha applied 1/2 at land preparation and 1/2 in equal splits 1 mo after transplanting and 1 wk before flowering; 18 kg P and 33 kg K/ ha were added at land preparation. Pump water was used

Growth and yield of rice + fish at Barddhaman, West Bengal, 1987 wet season.

Rice Rice

fish fish Characteristic without +

Rice Plant height (cm) 133.2 120.8 Effective tillers/plant 12.0 15.2 Panicle length (cm) 26.4 26.8 Grains/panicle 158.2 178.4 Grain yield (t/ha) 4.1 4.9 Straw yield (t/ha) 5.2 6.0 Fish Recovery (%) – 81.3 Increase in length (cm) – 8.2 Increase in weight (g) – 96.4 Fish yield (t/ha) – 0.7

to irrigate as needed. Water depth, 3- 5 cm at the outset, was gradually increased to 10-12 cm.

46 IRRN 13:4 (August 1988)

N + carbofuran at 0.75 kg ai/ha N alone 39 70 45 56

K. Sudhakara Babu, K. Ramaseshaiah, and Y. P. Prabhakara Rao, Regional Agricultural Research Station, Lam Farm, Guntur 522034, Andhra Pradesh, India

Tilapia fingerlings were stocked at 2 fish/m 2 35 d after transplanting. They were fed an inexpensive 1: 1 mixture of rice bran and mustard cake at 5% total body weight each morning. When fertilizer was topdressed, the water level was gradually lowered so that fish could take refuge in the drains.

Fish were harvested with rice in mid- Dec. A few hours before harvest, plots

were slowly drained, allowing the fish to move to the drains where they could be collected by dragnet and hand. Rice was cut with hand sickles about 15- 20 cm from the ground and bound into small bundles. The bundles were placed in rows over the stubble so that they did not touch the muddy ground.

Ten randomly selected plants from each plot were uprooted at harvest for

data collection. Growth and yield data for 10 randomly selected fish and total yields were recorded (see table).

With rice + fish, growth and yield characters of rice increased appreciably while plant height decreased. Fish weight and length increased considerably during the 4 mo cropping duration.

Pulse crop performance in a Grain yield and gross return a from different pulse crops. Andhra Pradesh, India, 1980-83.

rice-based cropping sequence Grain yield (t/ha) Gross return ($/ha) Crop

1980-81 1981-82 1982-83 Mean 1980-81 1981-82 1982-83 Mean

Farmers of coastal Andhra Pradesh, India, grow black gram Vigna mungo (L) Hepper as a relay crop with rainy season rice in about 0.25 million ha. Black gram seed is broadcast into the standing rice crop 24 d before rice harvest mid-Nov to mid-Dec. The black gram grows entirely on residual moisture and fertility, with no intercultivation or weeding. Average yield is about 0.8 t / ha. But recently black gram has suffered from wilt, root

Black gram 1.10 Mungbean 0.65 0.37 0.91 0.64 179 85 227 164 Chickpea b 0.07 0.05 0.06 b 17 13 15 Cowpea 0.71 0.51 0.32 0.51 109 98 74 94 Pigeonpea 0.34 0.19 0.11 0.21 78 44 38 53 Soybean 0.07 b 0.13 0.10 15

a US$1 = Rs 13.04. b Failed.

0.91 1.08 1.03 232 188 331 250

b 35 25

rot, and powdery mildew diseases. We the standing rice crop 3 d before rice evaluated five alternate pulse crops after harvest. rainy season rice in 1980-81 to 1982-83. Soybean, pigeonpea, and chickpea, The experimental site was a black with higher yield potential than black alluvium under Krishna delta. Rice gram, did not do well (see table). variety BPT3291 was transplanted the Mungbean and cowpea yields were first week of Aug with 80-20-37 kg satisfactory, but less than that of black NPK/ha. Pulse crops were broadcast in gram.

ANNOUNCEMENTS nematodes, microorganisms in postharvest handling, as well as breeding for resistance and disease

New IRRI publications

Rice seed health Rice ratooning Helpful insects, spiders, and pathogens —friends of the rice farmer (in Cebuano)

New book on rice diseases Advances in rice pathology, 484 pp, edited by S. Kannaiyan, was published

control. Sep 1987 by Tamil Nadu Agricultural To order, contact S. Kannaiyan, University, India. Its 24 chapters were Biotechnology Unit, Department of written by 31 plant pathologists with Agricultural Microbiology, Tamil Nadu broad experience in India, Bangladesh, Agricultural University, Coimbatore the United States, and IRRI. 641003, Tamil Nadu, India.

Chapters cover a broad spectrum of recent developments in rice disease management, including mechanisms of resistance, pathogenic races, epidemiology, disease forecasting, ecology of pathogens, insect vectors,

For instructions on preparation of brief reports of rice research to submit for publication in IRRN, see the inside front cover of this issue.

International Rice Research Newsletter Vol.13 No.4

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