International Rice Research Newsletter Vol.16 No.6

PUBLISHED BY THE INTERNATIONAL RICE RESEARCH INSTITUTE, P.O. BOX 933, MANILA, PHILIPPINES

VOLUME 16 NUMBER 6 DECEMBER 1991

IRRN GUIDELINES The International Rice Research Newsletter objective is:

"To expedite communication among scientists concerned with the development of improved technology for rice and for rice- based cropping systems. This publication will report what scientists are doing to increase the production of rice, inasmuch as this crop feeds the most densely populated and land-scarce nations in the world . . . IRRN is a mechanism to help rice scientists keep each other informed of current research findings." The concise reports contained in

IRRN are meant to encourage rice scientists and workers to com- municate with one another. In this way, readers can obtain more detailed information on the research reported.

Please examine the criteria, guidelines, and research categories that follow.

suggestions, please write the editor, IRRN, IRRI, P.O. Box 933, Manila, Philippines. We look forward to your continuing interest in IRRN.

Criteria for IRRN research report has international, or pan-national,

has rice environment relevance advances rice knowledge uses appropriate research design and data collection methodology reports appropriate, adequate data applies appropriate analysis, using appropriate statistical techniques reaches supportable conclusions

If you have comments or

relevance

Guidelines for contributors

The International Rice Research Newsletter is a compilation of brief reports of current research on topics of interest to rice scientists all over the world. Contributions should be reports of recent work and work-in- progress that have broad, pan-national interest and application. Only reports of work conducted during the immediate past three years should be submitted.

Research reported in IRRN should be verified. Single season, single trial field experiments are not accepted. All field trials should be repeated across more than one season, in multiple seasons, or in more than one location, as appropriate. All experiments should include replication and a check or control treatment.

All work should have pan-national relevance.

Reports of routine screening trials of varieties, fertilizer, and cropping methods using standard methodolo- gies to establish local recommenda- tions are not accepted.

Normally, no more than one report will be accepted from a single experiment. Two or more items about the same work submitted at the same time will be returned for merging. Submission at different times of multiple reports from the same experiment is highly inappropriate. Detection of such submissions will result in rejection of all.

Please observe the following guidelines in preparing submissions:

Limit each report to two pages of double-spaced typewritten text and no more than two figures (graphs, tables, or photos). Do not cite references or include a bibliography. Organize the report into a brief statement of research objectives, a brief description of project design, and a brief discussion of results. Relate results to the objectives.

analysis.

environment (irrigated, rainfed lowland, upland, deepwater, tidal wetlands).

Report appropriate statistical

Specify the rice production

Specify the type of rice culture (transplanted, wet seeded, dry seeded). Specify seasons by characteristic weather (wet season, dry season, monsoon) and by months. Do not use local terms for seasons or, if used, define them. Use standard, internationally recognized terms to describe rice plant parts, growth stages, environments, management practices, etc. Do not use local names. Provide genetic background for new varieties or breeding lines. For soil nutrient studies, be sure to include a standard soil profile description, classification, and relevant soil properties.

diseases, insects, weeds, and crop plants. Do not use common names or local names alone. Quantify survey data (infection percentage, degree of severity, sampling base, etc.). When evaluating susceptibility, resistance, tolerance, etc., report the actual quantification of damage due to stress that was used to assess level or incidence. Specify the measurements used. Use generic names, not trade names, for all chemicals. Use international measurements. Do not use local units of measure. Express yield data in metric tons per hectare (t/ha) for field studies and in grams per pot (g/pot) or per specified length (in meters) row (g/ row) for small scale studies. Express all economic data in terms of the US$. Do not use local monetary units. Economic information should be presented at the exchange rate US$:local currency at the time data were collected.

abbreviations, write the name in full on first mention, followed by the acronym or abbreviation in parentheses. Thereafter, use the abbreviation. Define any nonstandard abbreviations or symbols used in a table or graph in a footnote or caption/ legend.

Provide scientific names for

When using acronyms or

Categories of research published

GERMPLASM IMPROVEMENT genetic resources genetics breeding methods yield potential grain quality pest resistance

diseases insects other pests

stress tolerance drought excess water adverse temperature adverse soils

irrigated rainfed lowland upland deepwater tidal wetlands

seed technology

CROP AND RESOURCE MANAGEMENT soils soil microbiology physiology and plant nutrition fertilizer management

inorganic sources organic sources

integrated germplasm improvement

crop management integrated pest management

diseases insects weeds other pests

water management farming systems farm machinery postharvest technology economic analysis

ENVIRONMENT

SOCIOECONOMIC IMPACT

EDUCATION AND COMMUNICATION

RESEARCH METHODOLOGY

CONTENTS GERMPLASM IMPROVEMENT CROP AND RESOURCE MANAGEMENT

Yield potential Fertilizer management-inorganic sources 5 Ratooning ability of deepwater rice and ratoon crop herbage 18 Long-term effects of nitrogen, phosphorus, and potassium on irrigated

production lowland rice in Mekong Delta 6 Kneeing ability of promising submergence-tolerant rice lines 18 Effect of potassium application levels and time on rice

Grain quality 6 Element content characteristics of 51 good quality brown rices 6 Grain quality of some red rice genotypes

Pest resistance—diseases 7 Genetic analysis of bacterial blight (BB) resistance in rice anther

8 Resistance to sheath blight (ShB) and brown spot (BS) in lines derived

8 Resistance to sheath rot (ShR) of breeding lines derived from Oryza

culture progenies

from Oryza officinalis

officinalis

Pest resistance—insects 9 Resistance of rice varieties to whitebacked planthopper (WBPH) in the

10 Feeding behavior of the brown planthopper (BPH) on susceptible and greenhouse

resistant rice cultivars

Stress tolerance—adverse temperature 11 Cold tolerance of Yunnan rices at early seedling stage 11 Comparative performance of indigenous rice varieties for cold

tolerance in the hills of Nepal 12 Screening for cold tolerance in Nepal

Stress tolerance—adverse soils 13 Response of some rice cultivars to lime application on acid sulfate

soils

Integrated germplasm improvement—irrigated 13 New rice cultivar Marianna obtained through anther culture 14 Zhe 733, a high-yielding, blast (Bl)-resistant, good quality indica rice

14 Response to nitrogen of new dwarf fragrant rice varieties for

15 Aruna (MO 8), a high-yielding rice variety with seed dormancy and

15 Zhe 8619, a promising rice with high-yielding and high ratooning

16 Zhe 852, a short-duration, high-yielding rice variety for double-

16 Kanakam (MO 11), a high-yielding, semitall variety from Kerala,

for China

transplanted conditions

brown planthopper (BPH) resistance from Kerala, India

ability in China

cropped areas in China

India

Fertilizer management—organic sources 18 Effect of vitamins on spore germination and viability of Azolla

19 Use of rice straw under submerged conditions

Integrated pest managenment—diseases 19 Managing rice sheath blight (ShB) using fungal antagonists and

20 Detecting and purifying noncapsid protein in rice infected with grassy

20 Estimation of rice bacterial sheath brown rot (BSR) and rice blast (Bl)

microphylla sporocarps

organic amendments

stunt virus (RGSV)

severity in five Burundi highland swamps

spreaders against rice hispa (RH) 21 Efficacy of Beauveria bassiana combined with various stickers or

21 22

22 23 24 24 24 25

Integrated pest management—insects Mating sequence of rice leaffolder (LF) Murasmia patnalis Bradley Population fluctuation of leaffolder (LF) at different planting times in some rice varieties Survey of ricefield insects in Mbo and Ndop Plains of Cameroon Using chlorpyrifos to control gall midge (GM) Influence of some weather factors on rice stem borer (SB) infestation Chemical control of gall midge (GM) in the rice nursery Mirid predation on brown planthopper (BPH) eggs Comparison of yellow stem borer (YSB) catch in light traps

Integrated pest management—weeds 25 Weed control in wet seeded rice in Kerala, India 26 Weed control economics in transplanted rice (TPR)

Integrated pest management—other pests 26 Golden snail ( Pomacea sp.) use in animal feeds 27 Loss of rice grain yield and seedling vigor due to sheath rot (ShR) and

mealy bug interaction

Water management 27 Water use by irrigated summer rice 28 Water balance in bunded ricefields under different rainfed situations in

Central India

ANNOUNCEMENT

29 New IRRI publications Integrated germplasm improvement—upland 17 Performance of upland breeding lines and germplasm under periodic

17 BR20 and BR21: promising upland rices for Bangladesh coastal region moisture stress in erosion-susceptible soil

~

GERMPLASM IMPROVEMENT Yield potential Ratooning ability of deepwater rice and ratoon crop herbage production

T. Kupkanchanakul, B. S. Vergara, and K. Kupkanchanakul, IRRI

The only crop normally grown in areas with water depths exceeding 50 cm during the cropping season is deepwater rice (DWR). Establishing a second crop after rice is difficult because supplemental water is generally not available. In recent studies of a ratoon crop under controlled shallow irrigation at IRRI, varieties differed in their ratooning ability. Ratoons produced high herbage yields in a short time.

We evaluated the ratooning ability and herbage production of 45 DWR cultivars under natural field conditions at Huntra Rice Experiment Station, Ayutthaya, Thailand, in early 1991.

domized complete block design with four replications. The main crop was transplanted at 25- × 25-cm spacing, three seedlings/hill in Jul 1990 and harvested in Jan 1991. Water depth rose to 100 cm before flowering.

Main crop straw was cut 15 cm aboveground 7 d after harvest and the crop was allowed to ratoon. No irrigation, fertilizer, or crop protection was provided. Ratooning ability and herbage yield of the ratoon crop were determined at 40 d after cutting.

Only 31 cultivars produced ratoons (see table). Most DWCT’82 entries showed very good ratooning ability; among the BKNFR82002 breeding lines only one produced ratoons. Check variety Huntra 60 showed high ratooning ability, LMN111 and PG56 produced no ratoons. (This confirmed the ratooning ability of these check cultivars under controlled irrigation at IRRI in 1990.)

Herbage yield from the ratoon crop excluding 15-cm stubble) differed.

The experiment was laid out in a ran-

DWCT’82-1-10, DWCT’82-2-2,

Ratooning ability and herbage yield of DWR ratoon crop under natural deepwater condition. Huntra Rice Experiment Station, Ayutthaya, Thailand, 1991.

Cultivar Ratoon hills (% of main crop)

Dry herbage yield 40 d after cutting

kg/ha g/ratoon hill

BKNFR82002-1-2-9-5 0 0 0 BKNFR82002-1-2-9-6 0 0 0 BKNFR82002-1-2-9-7 38 98 2 BKNFR82002-1-4-2-7 0 0 0 BKNFR82002-1-4-2-8 0 0 0 BKNFR82002-2-2-3-1 0 0 0 BKNFR82002-2-5-4-5 0 0 0 DWCT'82-1-1 75 248 2 DWCT'82-1-10 91 418 3 DWCT'82-2-2 89 450 3 DWCT'82-2-10 89 426 3 DWCT‘82-2-15 88 351 2 DWCT'82-5-3 90 342 2 DWCT'82-19-3 87 273 2 DWCT'82-19-9 80 292 2 DWCT'82-20-9 90 411 3 DWCT'82-20-11 81 441 3 DWCT'82-20-15 89 206 1 DWCT'82-30-5 72 241 2 DWCT'82-31-11 87 287 2 DWCT'82-34-5 73 223 2 DWCT'82-36-20 65 179 2 DWCT'82-51-11 0 0 0 DWCT'82-51-14 0 0 0 DWCT'82-59-19 89 260 2 DWCT'82-68-20 69 173 2 DWCT'82-80-7 45 96 1 DWCT'82-90-19 79 216 2 DWCT'82-121-15 87 355 3 DWCT'82-123-1 74 221 2 DWCT'82-134-2-1-0 0 0 0 HTAFR77067-16-1 0 0 0 HTAFR82023-9 0 0 0 HTAFR83019-5 39 94 2 HTAFR83019-13 24 81 2 HTAFR83025 0 0 0 HTAFR84022 43 89 1 HTAFR84045 51 99 1 LMN111’80G1C5-37-85-42 24 154 4 RGA6-5-0-0 29 105 2 SPR7295-32-1-5-3 20 169 5 SPR76136-12-FC-292-2 27 59 1 Huntra 60 (check) 71 220 2 LMN111 (check) 0 0 0 PG56 (check) 0 0 0

Mean 46 162 2 LSD (0.05) 16 111 0.70 CV (%) 24.92 53.03 32.32 . .

DWCT’82-2-10, DWCT’82-20-9, and DWCT’82-20-11 had relatively high herbage yield; SPR7295-32-1-5-3 and LMN111 ’80GIC5-37-85-42 had high herbage yield/ratoon hill but low herbage yield/unit area because of a low percentage of ratoon hills.

Average herbage yield under natural field condition was about 10 times lower than yields reported under irrigated conditions. The soil in natural deepwater

fields dried very fast and cracked within 30 d after ratooning.

When cultivars that did not produce ratoons were excluded, herbage yield from the ratoon crop was highly correlated with ratooning ability ( r = 0.875**) and herbage weight per ratoon hill ( r = 0.446*). These results indicate that biomass production from a ratoon rice crop in deepwater areas could provide supplemental forage for farm livestock.

IRRN 16:6 (December 1991) 5

Kneeing ability of promising submergence-tolerant rice lines

A.S. Rao, P. S. S. Murthy, D. R. Rao, N. S. Reddy, and K. R. K. Murthy, Agricultural Research Station, Pulla 534401, West Godavari District, Andhra Pradesh, India

Kneeing ability is an important characteristic of rices grown in deepwater areas. We evaluated 11 promising submergence-tolerant lines and check variety CN540 for kneeing ability and yield performance in 1989 wet season.

Kneeing ability and grain yield of deepwater rice lines under 40-cm water. Pulla, West Godavari District, Andhra Pradesh, India, 1989.

Kneeing Grain yield (t/ha)

(score) a With With Variety ability

40-cm water 80-cm water

PLA7007 1 3.0 PLA7044 1

2.1 1.9

PLA8574 1 0.8

3.2 2.2 PLA8575 1 PLA7020 3

2.5 2.7

1.1

PLA7111 3 1.4

1.9 0.6 PLA7121 3 CN540

3.3 3 2.5

1.9 0.8

PLA7051 5 2.5 PLA7052 5

0.9 2.3

PLA7056 5 0.7

4.1 PLA7112 5 2.7

1.8 1.5

LSD (0.05) 0.6 0.2 a Standard evaluation system for rice.

Seeds were sown 11 Jun and seedlings transplanted 10 Jul. Water depth was maintained at about 2 cm. At 30 d after transplanting (DT), three plants/variety were pulled without damaging the root and placed horizontally on the soil. Kneeing ability was scored 8 d later. PLA7007, PLA7044, PLA8574, and PLA8575 scored 1 for kneeing ability (see table).

Water depth was increased to 80 cm from 40 DT. Yields were high only in PLA8574 and PLA7007; both had high scores for kneeing ability.

Grain quality Element content characteristics of 51 good quality brown rices

Qiu Lingcang, Pan Jun, and Duan Binwu, China National Rice Research Institute (CNRRI), Hangzhou 310006, China

We studied the content of 41 element characteristics of 51 good quality brown rices with high nutritional, cooking, or eating quality.

and Resource Department was sown in 1988. After threshing and dehulling, the brown rice was ground, mixed, and wet- digested with HNO 3 -HClO 4 . The digests were analyzed by inductively coupled plasma-atomic emission spectrometry using suitable reference standards.

and Sc lowest (see figure).

elements of quality rice grown on the CNRRI farm with those of conventional brown rice from the Taihu River valley, the order queues were similar:

P>K>Mg>Ca>Mn>Zn>Fe>Na>Al> Cu>Ni>Mo>V>Cr>Co

Seed from the CNRRI Rice Germplasm

Among the 41 elements, P was highest,

When we compared the contents of 15

CNRRI farm:

Taihu River: P>K>Mg>Na>Ca>Mn>Zn>Al>Fe>Cu> Ni>Mo>V>Cr>Co

Results of u test indicate significantly higher (P<0.01) P, K, Mg, Ca, Zn, Fe, Mo,

6 IRRN 16:6 (December 1991)

Element contents of 51 brown rices.

Ni, Cr, and Co, but significantly lower Al, The average coefficient of variation Na, and V for good quality rice than for (CV) of 41 elements is 67.6 ± 49.2%. conventional rice.

Grain quality of some red The qualities of various red rice geno- rice genotypes types grown in different crops at Mon-

compu were determined at the Central N. R. Bai, A. Regina, R. Devika, Rice Research Institute, Cuttack, India. S. Leenakumari, D. S. R. Devi, and Aruna showed minimum values for the C. A. Joseph, Rice Research Station, hulling and milling percentages; Karthika Moncompu, India expressed the maximum (see table).

Grain length was 5.11-7.05 mm and length/breadth ratio was 1.95 to 2.82. Water uptake was highest in Asha (R), and lowest in Kanakam and KAU168. Amylose content ranged from 16% in Pavizham to 21.9% in Remya.

Protein content was highest in Remya (10.9% dry basis) and lowest in Pavizham (7.5%). Elongation ratio ranged from 1.53 in Karthika to 2.23 in Aruna.

Grain quality attributes of 11 red rice genotypes. Kerala, India, 1989.

Brown rice Milled rice Genotype

Grain Grain L/B Hulling Milling Alkali Water Amylose Protein Elonga- length breadth ratio percentage percentage spreading uptake content content tion (mm) (mm) (% of (% of value (%) (% dry (% dry ratio

Bhadra 5.11 2.42 2.11 79.5 73.5 7.0 350 21.1 10.2 1.76 Asha(R) 6.20 2.58 2.40 80.0 73.5 6.0 365 18.9 9.4 1.61 Pavizham 5.32 2.72 1.95 79.5 73.5 3.0 315 16.0 7.5 1.69 Karthika 7.05 2.50 2.82 80.5 74.5 6.0 355 21.2 10.6 1.53 Aruna 5.39 2.55 2.11 74.0 64.5 3.0 240 20.6 9.6 2.23 Makam 5.33 2.31 2.39 79.0 70.0 6.0 260 18.6 9.4 1.62 Remya 6.56 2.60 2.52 75.5 70.0 6.0 320 21.9 10.9 1.92 Kanakam 5.38 2.53 2.13 76.5 68.5 2.0 230 20.6 9.5 1.75 KAU200 5.35 2.54 2.11 79.5 70.5 5.3 320 20.3 9.2 1.79 KAU204 5.32 2.46 2.16 75.0 67.5 5.0 325 20.3 9.4 1.84 KAU168 5.74 2.22 2.58 74.5 67.0 3.0 230 19.4 9.2 1.81

rough rice) rough rice) basis) basis)

an effective, quick way to transfer the resistance gene and obtain stable pollen progenies with BB resistance.

Of 579 H 2 pollen strains of seven combinations, 572 strains (95.5%) were uniform and stable, 62.9% with high or moderate resistance and 32.7% with no resistance. Additionally, 27 heterozy- gous strains (4.5%) showed segregating resistance (see figure).

The BB resistance of H 2 plants is more significant than that of F 2 plants. For example, in the progenies of Shennong 1033/75-34, lesion area variation is 5-100% in H 2 and 5-45% in F 2 . Growth duration and resistance show a significant relationship. BB resistance is higher in strains with longer growth duration.

H 2 strains varied greatly in growth duration, plant height, panicle length, and grain weight. Genetic analysis of results indicated that in the combination,

Pest resistance— diseases

a dominant epistatic gene controlled BB resistance. Broad heritability was more

Genetic analysis of bacterial blight (BB) resistance in rice anther culture progenies

Zhang Chengmei, Lu Jiaan, and Zhang Zhenhua, Crop Breeding and Cultiva- tion Research Institute (CBCRI), Shanghai Academy of Agricultural Sciences, Shanghai 201106; and Zhang Qi, CBCRI, Chinese Academy of Agricultural Sciences, Beijing, China

To study BB resistance inheritance in rice anther culture progenies, we crossed susceptible Shennong 1033 (japonica) with resistant varieties: indicas Zenith, 75-35, IR20; and japonicas Wase Aikoku 3, Pei Zhao 15, Bang Zhu Mang, Java 14. F 1 plants of the combinations were used for anther culture. BB resistance was evaluated by the IRRI standard system.

We observed the transfer of the resistance gene in pollen plants (H 2 ) and resistance stability in H 2 , H 3 , and H 4 . results indicated that anther culture was BB resistance reaction of anther culture H 2 populations derived from 7 combinations.


rmguevarra

Line

than 80%. Many types of pollen strains combined the two parents’ traits, with variation ranging close to that of F 2 progenies.

The stability of BB resistance and of other agricultural traits were analyzed in H 3 and H 4 (see table). In pollen plants, these were all relatively stable in different generations. In stable H 2 pollen strains, the resistance capability and character uniformities did not vary with generation advance (H 3 and H 4 ).

We concluded that the anther culture method effectively transfers the resistance gene.

Stability of pollen strain resistance to bacterial blight.

Cross Generation Strain no. Lesion area a Strain no. Lesion area b

(%) (%)

Shennong 1033/Zenith H 2 89-3710 3.0 ± 0.2 89-3724 16.7 ± 1.6 H 3 2.0 ± 1.8 16.8 ± 1.4 H 4 2.3 ± 0.1 15.7 ± 1.4

H 3 4.7 ± 0.2 H 4 4.9 ± 0.1 15.7 ± 1.4

H 3 4.9 ± 0.1 13.3 ± 1.6 H 4 4.9 ± 0.1 12.8 ± 1.2

H 3 4.9 ± 0.1 13.9± 1.2 H 4 4.9 ± 0.1

Shennong 1033/75-34 H 2 89-3841 4.7 ± 0.2 89-3873 14.5 ± 0.8 l4.7 ± 1.2

Shennong 1033/Java 14 H 2 89-3753 2.9 ± 0.2 89-3924 14.0 ± 1.3

Shennong 1033/Pei Zhao 15 H 2 89-3795 4.9 ± 0.1 89-3819 14.9 ± 1.1

14.1 ± 1.1

a All values are equivalent to R (resistant). b All valuea are equivalent to MR (moderately resistant).

Resistance to sheath blight (ShB) and brown spot (BS) in lines derived from Oryza officinalis

P. Lakshmanan, Plant Pathology Depart- ment, Agricultural College and Research Institute (ACRI), Madurai 625104; and R. Velusamy, Entomology Department, ACRI, Vallanad 627252, Tamil Nadu, India

We evaluated 87 breeding lines derived from O. officinalis for resistance to ShB caused by Thanatephorus cucumeris (Frank) Donk, and BS caused by Cochliobolus miyabeanus (Ito & Kuribayashi) Drechsler ex Dastur.

In the field, one row per line and check TKM9 were transplanted at 30- × 15-cm in 3-m-long plots, in a randomized block with three replications.

We assessed ShB weekly and BS biweekly from active tillering to the milk stage, using the Standard evaluation system for rice (SES). Lines completely free from ShB and BS were artificially inoculated for further evaluation.

Disease incidence was evaluated in the greenhouse by stem tape inoculation for ShB and spore suspension spray for BS, on 21 seedlings/line. Actively tillering plants were inoculated with 20-d-old ShB pathogen cultured on autoclaved rice stem pieces, inserted into the sheaths, 5 cm above the water line. For BS inoculation, plants were sprayed with a l0 7 conidia/ml suspension.

for ShB and every 10 d for BS from the Disease severity was assessed every 7 d


Lines derived from O. officinalis showing resistance to ShB and BS.

Lines Intensity (0-9 scale)

ShB BS

1 (highly resistant)

3 (resistant)

IR54742-6-1-14-15-3 IR54742-33-18-20-3-2 IR54745-2-10-17-8-3 IR54745-2-23-19-8-2 IR54742-1-11-17-12-3

IR54742-1-11-17-12-1 IR54742-1-11-17-12-3 IR54742-1-11-17-26-2

IR54742-11-1-9-15-1 IR54742-6-20-3-9-3

IR54742-33-9-14-26-4 IR54745-2-21-12-17-4 IR54745-2-34-3-10-2

IR54742-50-19-19-1-1 IR54751-3-38-10-15-3

IR54742-50-19-19-1-3

9 (highly susceptible) TKM9 (check)

IR54742-1-11-17-26-1 IR54742-1-17-20-8-3 IR54742-33-9-14-26-4 IR54742-33-18-20-3-1 IR54742-33-18-20-3-2 IR54742-38-13-15-11-1 IR54745-2-10-17-8-1 IR54745-2-21-12-17-4 IR54745-2-23-19-8-1 IR54745-2-23-19-18-2 IR54742-1-11-17-12-1 IR54742-1-11-17-12-3 IR54742-1-19-11-8-2 IR54742-6-20-3-22-3 IR54742-6-20-9-3-2 IR54742-11-22-2-22-2 IR54742-18-17-20-15-1 IR54742-22-14-24-22-3 IR54742-22-19-3-7-3 IR54742-31-9-26-15-2 IR54742-33-18-20-3-2 IR54745-2-10-17-8-3 IR54745-2-21-12-17-5 IR54745-2-34-3-10-2 TKM9

time symptoms appeared on the suscep- Under artificial inoculation, 5 lines were tible check until the milk stage. highly resistant to ShB and 10 to BS (see

the derived lines were ShB- and BS-free. Under natural infection, 87 and 48 of table).

Resistance to sheath rot We evaluated 87 breeding lines derived (ShR) of breeding lines from O. oficinalis for resistance to ShR derived from Oryza officinalis caused by Sarocladium oryzae (Sawada)

W. Gams & Hawksw. P. Lakshmanan, Plant Pathology Depart- Twenty plants for each derived line ment, Agricultural College and Research were transplanted into 1-row, 3-m-long Institute (ACRI), Madurai 625104; and R. plots spaced at 30 × 15 cm. Beds were Velusamy, Entomology Department, ACRI, laid out in randomized blocks with three Vallanad 627252, Tamil Nadu, India replications. From booting stage onward,

we evaluated disease intensity weekly with Reactions of derived O. officinalis lines to ShR.

the Standard evaluation system for rice Designation

(SES). IR20 served as the susceptible Intensity (0-9 scale) check. Single-grain inoculation Mealy bug inoculation ~

In the greenhouse, disease-free lines were artificially inoculated using two methods. We inoculated one set of lines with a 15-d-old, single-grain culture in between the flag leaf sheath and the unemerged panicle.

In the other set, rice mealy bugs (Brevennia rehi Lindinger) were mass- reared using 45-d-old TNl rice. Crawlers were collected and soaked in S. oryzae spore suspension for 15 min (10 7 conidia/ ml). Crawlers were placed in between the flag leaf sheath and the unemerged panicle using a camel hair brush.

Fifteen derived lines were completely disease-free under natural infection, only a few lines exhibited high resistance under artificial methods (see table). The check had maximum disease severity under all conditions.

1 (highly resistant)

3 (resistant)

7 (susceptible)

9 (highly susceptible)

IR54742-6-34-17-11-1 IR54742-18-3-8-22-1 IR54742-22-14-3-7-2 IR54742-22-19-3-7-1 IR54742-33-9-14-26-3 IR54742-33-18-20-3-2 IR54742-33-37-16-10-1 IR54745-2-21-12-17-1 IR54751-1-19-13-17-1 IR54742-22-14-24-22-3 lR54742-31-21-20-10-3 IR54742-22-19-3-7-3 IR54742-2-21-12-17-5

IR54742-33-18-20-3-1 IR54745-2-10-17-8-3

IR54742-6-34-17-11-1 IR54742-18-3-8-22-1 IR54742-22-14-3-7-2 IR54745-2-21-12-17-1

IR54742-22-14-24-22-3 IR54742-22-19-3-7-1 IR54742-33-9-14-26-3 IR54742-33-18-20-3-2 IR54742-33-37-16-10-1 IR54751-19-13-17-1

IR54742-22-19-3-7-3 IR54742-31-21-20-10-3 IR54742-33-18-20-3-1 IR54745-2-16-17-8-3 IR54745-2-21-12-17-5

Pest resistance Resistance of rice varieties to WBPH in the greenhouse. China. 1986-90.

insects Variety Damage Variety

Damage score a score a

Resistance of rice varieties Shanyougui 8

to whitebacked planthopper Bangriai 7

(WBPH) in the greenhouse 84570 84547 Chuangmi no. 1

G. W. Hu, J. F. Ma, and J. Tang, China National Rice Research Institute, Hangzhou 310006, China

We screened 916 new rice varieties and breeding lines during 1986-90 for resistance to WBPH Sogatella furcifera by using the bulk seedling test. Test entries were sown in 20-cm rows in plastic seedboxes at 20 seeds/row. Each entry had three replications.

Seedlings were infested 7 d after sowing with second- to third-instar WBPH nymphs at 6-8 nymphs/seedling. Plant damage was scored when all plants of susceptible check TNl had died.

Ninety of the test entries showed resistance to WBPH (see table).

Chuangmi no. 2 8603 8604 2314 851193 851515 851633 853161 853209 352 Qishuangzhan Xiangzheng 21 85-2-591 Guangye 90 7526-4 1296 Sixizhan Zhehu no. 1 E3-14 E3-57 E3-147 Jing 15 Nonghu no. 3 Dianrui 138 Dianrui 236 H11 Liaoyan 283

3

Mingdao 580 3

Liaoyanru no. 4

Wanqingzao no. 2 3

3 C710

3 Sanluzhan no. 7

3 3 3 1 3

3 3 1 3 3 3 3 1 3 1 0 1 1 1 3 3 3 3 3 3 3 3 3 1 1 3 3

883016 Zhong 86-44 Zhong 86-51 Zhongyu 88-6 Zhongyu 88-9 3123 Jiangyou 594 85-151 Wanhui 500065 50239 Nanjing 58156 6267 Dan42- 1 Shuangerai Fu 8329 Fu 8456 Fu 8531 V20 A x Pinghui no. 2 Ping 10 H8702 860 13 46-204 HA8517 HA85-183 V49 V20 A x 1126 Yuwanfu no. 5

3 3 1 3 3 3 3 3 1 3 1 3 3 3 3 1 3 3 3 3 3 1 1 0 1 3 1

continued on next page


-

-

rmguevarra

Line

Radioactivity of insect plus excreted honeydew in relation to total duration of ingestion patterns produced by N. lugens on susceptible IR22 ( • ), and resistant IR62 ( ° ),


The total radioactivity of the insect plus excreted honeydew increased expo- nentially with ingestion pattern duration (see figure). Insects on the resistant cultivar followed the same logarithmic increase, but the total amount of label taken up was significantly less than that taken up by those on the susceptible cultivar.

We investigated the role of feeding deterrents (oxalic acid and beta-sitosterol) in relation to reduced sap ingestion from the resistant cultivar. Rootless tillers were immersed in 0.5% (wt/vol) solutions of either compound. Insect feeding behavior was monitored.

Both compounds induced significant insect weight loss with little influence upon the ingestion pattern duration. This affected the sap ingestion rate (see table). Either or both plant components may be responsible for the reduced sap ingestion and therefore resistance in rice cultivar IR62.

monitoring the amount of label within the insect and its excretion after 24 h on the plant. Honeydew excretion was monitored simultaneously by slowly revolving the insect and plant so that honeydew droplets fell separately onto pH indicator paper.

Feeding behavior of the brown planthopper (BPH) on susceptible and resistant rice cultivars

R. M. Hopkins, 8 Headlands, Kettering, Northants, NN15 7HP, United Kingdom

The feeding behavior of unstarved, newly molted, adult female BPH Nilaparvata lugens Stå1 was assessed on single tillers of susceptible (IR22) and resistant (IR62) rice cultivars.

Ingestion patterns were electronically monitored using a direct-current system, which recorded voltage changes accom- panying stylet activity within the plant. Sap ingestion was assessed by incorporating radioactive P into the rice plant and

Table continued

Damage score a score a Variety

Fu 8971 3 Shuangchao no. 25 1 Fu 8922 3 Nanjing 3714 3

Variety Damage

Fu 85-30 Zhehu 102 Zhehu 129 Zhongyu 87-3 6ET- 198

3

17267 3 61 jing 3 Ewan no. 3 3 Zhongguai 3 Dongtingzhengzhuru 3

3 3 3 3

1673 3 Zhongzuo 8531 3

Zhongxian 86-6 3

3 85-183 88 Nan 14 3 LS8713 3 Zhongyu 89-10 3 8807 3 8810410 1 HA79317-4 3 Shun 44 1 Xianjing no. 1 3

a By the Standard evaluation system for rice.

feeding deterrent solutions. a

Control Beta- Oxalic Control (H 2 O) sitosterol acid (H 2 O)

Duration of phloem 7.5 a 16.0 a 0.3 a 1.6 a

Duration of xylem 35.3 a 22.9 a 6.8 b 33.3 a

Feeding behavior and weight change of N. lugens over 24 h on rootless rice tillers immersed in control and

Susceptible cultivar IR22

Resistant cultivar IR62

(0.5% wt/vol) (0.5% wt/vol)

ingestion pattern (%)

ingestion pattern (%)

weight change Mean percentage 17.8 a

2.8 a –6.0 b

–31.3 b –8.4 b –5.9 a

a In a row, values followed by the same letter are not significantly different at the 5% level (Mann-Whitney U test).

- -

glutinous, the least. Although indica- upland rices had the lowest score and indica-lowland the highest, in general japonicas have significantly greater cold tolerance than indicas, upland rices greater tolerance than lowland, and

nonglutinous greater than glutinous. The table gives paired comparisons of

cold tolerance among 12 forms. The difference in cold tolerance between japonica and indica holds up, but that between lowland and upland and between nonglutinous and glutinous is only partly substantiated.

Stress tolerance—adverse temperature

Cold tolerance of Yunnan rices at early seedling stage

Chen Yong and Lu-Yuan Dai, Crop Germplasm Station, Yunnan Academy of Agricultural Sciences, Kunming 650205, China

We screened 2,763 local Yunnan rice varieties for cold tolerance at the early seedling stage during 1987-89. Healthy germinating seeds (100/variety) were chilled at 5 °C for 10 d, then put under sunlight for 10 d. Recovery was assessed on a 1-9 scale, where 1 = highly resistant, 3 = resistant, 5 = medium resistant, 7 = susceptible, 9 = highly susceptible.

We found only 19 highly resistant varieties (less than 3% of those tested). Fifteen originated in Jinping and Shangji- ang counties, 2 upland varieties in Changyuan county.

Japonica-lowland-glutinous rice has the best cold tolerance; indica-lowland-

Paired comparison of cold tolerance among 12 rice forms in Yunnan, China.

Form Varieties Cold tolerance (no.) (av score)

U-valuea

Indica-upland Indica-lowland Japonica-lowland Japonica-upland

Lowland-glutinous Lowland-nonglutinous Upland-nonglutinous Upland-glutinous

Indica-glutinous Indica-nonglutinous Japonica-nonglutinous Japonica-glutinous

17 1756 700 290

1853 603 123 I84

1448 325 40 I 589

6.29 8.12 7.25 7.46

7.94 7.69 7.55 7.28

8.11 8.07 7.33 7.30

1.80

5.66**

11.45**

a Significant at 5% (*) and 1% (**) levels.

Comparative performance of indigenous rice varieties for cold tolerance in the hills of Nepal

B. R. Sthapit (present address: Centre for Arid Zone Studies, University College of North Wales, Thoday Building, Bangor, Gwynedd LL57 2UW, Wales, UK), Lumle Regional Agricultural Re- search Centre (LRARC), P.O. Box No. 1, Kaski, Pokhara, Nepal

Injury due to cold temperature occurs at different stages of rice crop growth in different areas of Nepal, depending on altitude and temperature of irrigation water. Screening of exotic materials from the International Rice Cold Toler- ance Nursery at Lumle (1,400 m) has not been promising: most entries showed good cold tolerance at seedling and vegetative stage but failed to produce grain because of incomplete panicle exsertion or spikelet sterility. Delayed heading, degeneration of spikelet tips,

and chaffiness of panicles are common symptoms in wetland rice transplanted in Jul above 1,400 m elevation.

Indigenous rice varieties Chhomrong, Seto Bhakunde, and Himali Marshi had performed well at Lumle. We collected 79 indigenous varieties from Lumle and Pakhribas Research Command areas, with altitudes from 700 to 2,000 m asl, and evaluated them at Lumle for cold tolerance and agronomic traits at vegetative and reproductive stages. Mean tempera-

tures at Lumle fall below 20 °C toward the beginning of the reproductive phase (Table 1). Forty-one genotypes showed good cold tolerance at the reproductive stage. Data for the 10 best entries are given in Table 2.

These indigenous germplasm also show good tolerance for diseases associated with low temperature (neck blast Pyricularia oryzae and sheath rot Acrocylindrium oryzae ).

Most materials collected from above

Table 1. Meteorological data for Lumle (28°N 83°E) in 1990.

Av temperature (°C) Relative Total Av

Max Min Mean Water a (%) (mm) (h) Month humidity rainfall sunshine

May Jun Jul Aug Sep Oct Nov

Mean Total

23.3 24.7 24.0 23.7 23.5 21.1 19.3 22.8

14.6 17.1 17.6 17.4 16.6 12.2 11.4 15.3

19.0 20.9 20.8 20.6 20.1 16.7 15.2 19.0

NR NR 22.0 20.8 19.6 17.8 NR 20.1

82.4 92.2 97.3 95.2 92.5 81.2 72.3 87.6

325 1107 1 407 1088 978 315

0

5220

5.7 4.2 2.1 2.7 4.1 8.6 9.3 5.2

36.7

a NR = not recorded.


1. Temperature and rainfall patterns at Lumle (1400 m), Chhomro (2000 m), and Tapu (1000 m) testing sites in Nepal. Data are averages of 10 yr (1980-89), 4 yr (1986-89), and 3 yr (1987-89), respectively. Legend: = max temp °C; = mean temp °C; = min temp °C.

Table 2. Performance of selected indigenous rice varieties for cold tolerance at LRARC. Nepal, 1990.

Cold Yield (t/ha) Genotype Altitude a Plant tolerance Spikelet Crop

(m) height (1-9) b sterility duration moisture at 12%

(cm) (1-9) b (d) content GS2 GS6

Silange Chhomrong Kalo Patle Tangle Darmali Dangsing Damadi Phalame Bhuin dhan Bhatte Rato Darmali Rato Takmare

Range Mean

1900 NE 2000 NE 1600 SE 1700 NE 1620 SW 1700 NE 1600 1700 SE 1600 W 1800 SE

700-2000

111 3 137 1 133 1 160 3 130 3 137 1 125 1 118 1 133 1 117 1

90-151 1-5 125±13.7 2±1.2

1 2 3 1 1 1 3 1 5 1 3 1 1 1 1 1 1 1 5 1

1-7 1-5 2.9±1.7 1.6±1.0

140 144 144 154 150 143 150 154 153 140

138-170 152±29.1

5.3 4.1 4.1 4.1 4.0 3.9 3.8 3.7 3.6 3.6

0.9-5.3 3.05 ± 0.61

a NE = northeast, SE = southeast, SW = southwest, W = west. b By the Standard evaluation systemfor rice GS2 = at tillering, GS6 = at anthesis.

1,500-m altitude that show good cold Thorough collection and evaluation of tolerance had dark grains. They will be local rice germplasm would help identify grouped according to phenology and plant donors of cold tolerance at anthesis, cur- height for further use in cold tolerance rently lacking in our breeding program. breeding.

Screening for cold tolerance in Nepal

B. R. Sthapit (present address: Centre for Arid Zone Studies, University College of North Wales, Thoday Building, Bangor, Gwynedd LL57 2UW, Wales, UK), Lumle Regional Agricultural Research Centre (LRARC), P.O. Box No. 1, Kaski, Pokhara, Nepal

have been released for cold tolerance in the midhills. Their performance above 1,400 m asl is poor.

This is not surprising: breeding for low temperature tolerance in Nepal is limited because most research stations are

sited below 500 m asl, in the lower hills and the Terai.

Cold stress in rice occurs at specific growth stages in different altitude regime (Fig. l), and cold tolerance nurseries have been established at off-station research (OSR) sites to include both the diversity and complexity of high-altitude rice production systems.

ture does not fall below 20°C until the crop reaches spikelet filling. At Lumle (1,400 m), mean air temperature does not fall below 20°C until the beginning of the reproductive stage. At Chhomro (2,000 m), mean air temperature is low (15-20°C) throughout the growing season. Water temperatures recorded at Lumle and Chhomro during anthesis are 19.1-21.2 and 15.0-21.2 °C, respectively.

At Tapu, chilling injury in rice is induced by cool air temperatures around ripening time; at Lumle and Chhomro, it is attributed to both cold weather and cold water, and to their durations, at different growth stages.

Cold Tolerance Nursery, including both indigenous and exotic rice genotypes, at Yampaphant (475 m), Tapu, Lumle, and Chhomro during 1987 and 1988. (Since 1985, 79 local and 528 exotic entries have

At Tapu (1,000 m), mean air tempera-

We evaluated four sets of National Rice

Rice is grown in all agroecological zones of Nepal, from the foothills to the high mountains. Double cropping is practiced up to about 900 m, and rice reaches its altitudinal limit at 2,000 m.

Chilling injury limits both the rice- producing area and the length of the growing season. Above 1,000-m altitude, cool weather and cold irrigation water cause delayed heading, leaf yellowing, partial panicle exsertion, spikelet degeneration, spikelet sterility, and low yields in wetland rice transplanted in July. Poor germination and slow seedling growth are additional symptoms in irrigated short- duration rice seeded in Feb below 900 m.

Of 31 rice varieties recommended so far by the National Rice Research Program, only Khumal 2 and Palung 2


It is a dihaploid line, obtained from a 1983 F 1 hybrid combination Belozem/ Plovdiv 22 through anther culture.

We tested Marianna alone and with other cultivars until 1986. From 1986 to 1989, it was tested in some regular trials at State Cultivar Commission stations. It was acknowledged as an original cultivar at the commission’s 45th plenary session.

Marianna is related to the japonica rices. Its vegetative phase is 121-125 d,

Integrated germplasm improvement— irrigated

Table 1. Chemical characteristics of acid sulfate soil at Unit Tatas Substation, Central Kalimantan, Indonesia.

0-20 cm deep 20-40 cm deep

pH (H 2 O) 3.95 3.90 Total N (%) 0.41 0.19 Organic C (%) 2.78 Available P (ppm) 17.63 Exchangeable K 0.19

(meq/l00g) SO 4 (%) 0.12 Al 3+ (meq/100 g) 14.19 Na (meq/100 g) 0.12 Fe 3+ (meq/100 g) 6.16 Particle size (%)

Sand 0.22 Silt 33.41 Clay 66.37

1.70 32.96

0.13

0.05 15.70 0.26 5.59

0.21 31.14 68.65

Table 2. Effect of lime on yield of rice cultivars in acid sulfate soils at Unit Tatas Substation, Central Kalimantan, 1989 dry season.

Grain yield (t/ha) Lime (t/ha) BW267-3 CR261-7039-236 IR6023-10-1-1 Kapuas IR26

0 1.7 1.4 1.4 0.5 1.0 2.1 1.9 2.0 2.6 1.7

Mean 2.1 1.6

2.1 1.5 1.5 2.1 1.4 1.7 1.3

2.0 2.1 2.0 2.1 2.6 2.2 1.8 2.1 1.7

H. Rosmini and M. Salwani, Banjarbaru Research Institute for Food Crops, P.O. Box 31, Banjarbaru, South Kalimantan, Indonesia

We studied the effect of lime on rice cultivar yields in acid sulfate soils at Unit Tatas Substation, Central Kalimantan, during the 1989 dry season (Table 1).

In split-plot design with three replications, four lime levels (0, 0.5, 1.0, and 2.0 t/ha) were the main plot treatments and five rice cultivars (BW267-3, CR261-

7039-236, IR6023-10-1-1, Kapuas, and IR26) were subplot treatments. Lime was applied 15 d before transplanting. Three 21-d-old seedlings/hill were transplanted at 20- × 20-cm spacing in 4- × 5-m plots. At transplanting, we fertilized the rice basally with 90 kg N/ha, 26.4 kg P/ha, and 41.5 kg K/ha.

Yields in plots with 2.0 t lime/ha were significantly higher than those at other levels (Table 2).

In the cultivar treatments, Kapuas and BW267-3 yielded significantly higher than other varieties. In general, yield increased as lime was added.

Response of some rice cultivars to lime application on acid sulfate soils

been screened, including internationally known cold-tolerant checks Stejaree 45, Akiyudaka, China 1039, Palung 2, Fuji 102, and Phalame.) Leaf color, panicle exsertion, spikelet sterility, and yield parameters were scored visually at seedling, booting, anthesis, and maturity stages.

Above 1,400 m, most of the exotic varieties either failed to produce panicles or produced degenerated spikelets with a high degree of sterility. Yield performance of indigenous cultivars was reliable above 1,300 m (Fig. 2). At 1,500 m altitude, local variety Chhomro outyielded all other varieties; at 2,000 m, its performance was outstanding. This variety demonstrated an ability to tolerate

chilling at different growth stages at all altitudes.

has released Chhomro as Chhomrong dhan, the first indigenous variety for areas above 1,400 m asl. It also has been included as a cold-tolerant entry in the International Rice Cold Tolerance Nursery and LRARC’s chilling-tolerant rice breeding program. Results on segregating materials resulting from crosses between Chhomrong and exotic cold-tolerant lines are very promising.

Identification in recent years of Chhomrong dhan and several other varieties suitable for the low to high hills of Nepal has confirmed the value of field screening at different altitudes.

The National Variety Releasing Board

Stress tolerance—adverse soils 2. Yield of Chhomro and mean yields of NRCTN across altitudes, 1987-88.

New rice cultivar Marianna obtained through anther culture

P. Boyadjiev, Institute of Introduction and Plant Genetic Resources, K. Malkov- Sadovo, Bulgaria

Marianna is a new short-stemmed, lodging-resistant rice cultivar.


Characteristics of Marianna compared with standard Krasnodarsky 424.

Indicator Krasnodarsky 424 Marianna

Stem height (cm) Preflag length (cm) P'reflag width (mm) Central panicle length

Seeds (no.) in central panicle

1000-seed wt (8) Av yield from a

panicle (8) Stem thickness (mm) Yield (t/ha)

(cm)

116.0 36.9

1.2 19.8

104.4

31.0 2.1

0.9 5.4

120.0 43.2 1.4

21.0

131.7

32.5 2.4

1.5 6.1

comparable to that of standard Krasnodarsky 424 (see table). It has tall, thick, nonlodging stems, and wide, erect, intensively pigmented leaves. Increased dynamics characterizes initial growth and development phases.

The egg-shaped grain is suitable for mechanized polishing and is highly resistant to breakage.

Zhe 733, a high-yielding, blast (BI)-resistant, good quality indica rice for China

Yan Wenchao, Crop Institute, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021; Cai Guohai, China National Rice Research Institute, Hangzhou 310006, China

In recent years, indica rice breeders have been incorporating multiple resistance into high-yielding varieties. We identified Zhe 733 as having good yield potential and B1 resistance rated 3 by the Standard evaluation system for rice (SES). Zhe 733 was a multiple cross of IR30, IR29, Fongxuan 4, and Chi-Kuai- Ai-Xuan, released in Mar 1991 as an early rice in the double-cropped Yangtze River area.

potential under normal fertilization. In regional trials in 1990, it yielded 6.4-7.8 t/ha (Table 1), 6-12% higher than the check Guangluai 4. Average growth duration was 112 d in Zhejiang, 2 d earlier than Guangluai 4. Approximately 55,000 ha is now planted to Zhe 733 in South China. Morphoagronomic characters are given in Table 2.

Zhe 733 had high, stable yield


Table 1. Bl resistance and yield potentials of Zhe 733 in China, 1990.

Yield (t/ha) Site

Resistance to B1 a

Zhe 733 Guangluai 4 Zhe 733 Guangluai 4

Hangzhou, Zhejiang Changsha, Hunan Nanchang, Jiangxi Fuzhou, Fujian

7.8 7.8 6.5 6.4

6.9 6.8 5.5 6.1

3 3 1 3

7 9

9

a By SES.

Table 2. Morphoagronomic characteristics of Zhe 733 at different sites in China, 1990.

Site Growth Plant Panicle Grains Fertile Sterility 1,000- duration height length (no,/panicle) grains

(4 (crn) (cm) (no./panicle) (%) wt (g)

Hangzhou, Zhejiang Changsha, Hunan Nanchang, Jiangxi Fuzhou, Fujian

113 111 112 111

81 83 79 80

19.8 20.4 19.0 19.1

Appearance, milling recovery, chemical properties, cooking and eating quality meet the China national index for high quality rice. Grain length is 6.8 mm, with a 2.8 length-breadth ratio. The grain is semitranslucent with 24.9% amylose,

89 98 84 90

72 80 67 73

19.1 18.4 20.2 18.9

25.8 26.9 25.7 25.7

10.3% protein content, low-gelatinization temperature (5.3 alkali spreading value), and medium gel consistency (60 mm). Hulling recovery is 8 1.9%; milling recovery, 74.1%; and head rice recovery, 52.6%.

Response to nitrogen of new dwarf fragrant rice varieties for transplanted conditions

P. S. Bisht, P. C. Pandey, and P. Lal, Agronomy Department, G.B. Pant University of Agriculture and Technol- ogy, Pantnagar, Nainital District 263145, Uttar Pradesh, India

Pusa Basmati 1 and Kasturi are new dwarf fragrant rice varieties released in India in 1990. Pusa Basmati 1, a semidwarf of medium duration (133-135 d). has a yield potential of 4 t/ha. Kasturi is semitall, of medium duration (130-135 d) with a yield potential over 4 t/ha. Both varieties have long, slender grains with strong aroma. Kasturi also has good kernel elongation. Both are suited to the irrigated ecosystem and have export potential.

We compared Pusa Basmati 1, Kasturi and another promising variety, HKR228, with local check Basmati 370 at 60, 90, and 120 kg N/ha under optimum management. The soil was Aquic Hapludoll, silt loam, with pH 7.9, 1.1% organic C, CEC 20 meq/100 g, and 0.1% total N. The

Performance of newly released Basmati rice varieties at different N levels at Pantnagar, 1990 wet season.

Variety Grain yield (t/ha) at

14% moisture

N 60 N 90 N 120 Mean

Pusa Basmati 1 Kasturi HKR228 Basmati 370 (local check)

Mean

Treatment

Variety N rate Variety × N interaction

2.8 3.0 3.0 2.2

2.8

3.1 3.5 3.4 2.8

3.2

3.2 3.7 3.5 2.8

3.3

3.0 3.4 3.3 2.6

LSD (0.05)

0.2 0.5 ns

experiment was laid out in split-plot design, with four replications (N rate in main plots, and varieties in subplots).

(20 Jun sowing) and transplanted on 20 Jul with basal application of 17.6 kg P, 24.2 kg K, 10 kg Zn/ha as per normal practice. We applied urea in three splits: 1/2 basal, 1/4 at tillering, and 1/4 at 1 wk before panicle initiation.

The Basmati varieties showed no differential response to N. N response

Seedlings were raised in wet nurseries

was significant up to 90 kg N/ha (see table). The new Basmati varieties yielded significantly higher than Basmati 370. Kasturi and HKR228 produced almost similar yields (3.3-3.4 t/ha) that were significantly higher than that of Pusa Basmati 1 (3 t/ha).

Aruna (MO 8), a high-yielding rice variety with seed dormancy and brown planthopper (BPH) resistance from Kerala, India

N. R. Bai, R. Devika, A. Regina, S. L. Kumary, D. S. Radhadevi, and C. A. Joseph, Rice Research Station (RRS), Moncompu, India

Kuttanad is a unique delta region in Kerala, with 52,000 ha of riceland 0.5-2 m below sea level. Wet season rice harvest coincides with the monsoon. Rice grains often germinate within the panicle. Pests, especially BPH, are endemic because of the warm, humid climate. Many popular high-yielding varieties have neither BPH resistance nor seed dormancy.

Aruna (MO 8)—culture KAU93 derived from Jaya/Ptb 33—was released in 1990. It has red-kerneled, medium- bold grains and 1-mo seed dormancy. The short-duration (110 d) dwarf rice is also resistant to BPH.

In field trials 1983-84, Aruna (MO 8) consistently outyielded local checks (Table 1). It also showed resistance to many pests (Table 2).

Table 1. MO 8 (Aruna) yields in Kerala, India.

Grain yield (t/ha)

MO 8 Check variety a

Trial

Rice research station, 5.3 4.9 Moncompu, 1983-84, 3 seasons

1984 wet season

PVT-2, 1984 wet season, 8 locations

6 locations

3 seasons

Multilocation trials, 5.2 4.4

All India Coordinated trials 3.4 2.9

PVT-2, 1985 dry season, 3.8 2.5

Farm trials, 1987-89, 4.3 3.6

Rasi for PVT-2. a Jyothi for research station, multilocation, and farm trials and

Table 2. MO 8 reaction to pests at RRS Moncompu and in Hyderabad. a

Score at RRS Moncompu

Variety Score at DRR b , Sheath Sheath Stem Leaf Gall BPH d BPH Hyderabad d

blight c rot c borer c roller c midge c

KAU93 1.4 3.7 1.0 1.9 1 .0 1.7 2.2 2.5 Jyothi 4.7 4.5 3.0 3.2 3 .0 3.7 2.3 4.2

a Scored by Standard evaluation system for rice (SES) on a scale of 0-9. b Directorate of Rice Research. c Field screening. d Seedling screening.

Zhe 8619, a promising rice with high yields and high ratooning ability in China

Jin Qingsheng, Qiu Boqin, and Lu Rubi, Crop Institute, Zhejiang Academy of Agricultural Sciences (ZAAS), Hangzhou 310021, China

Zhe 8619, a semidwarf indica variety derived from Milyang 56/4B-58 at ZAAS, is suitable for two seasons in the double-cropped area of southern China. In Zhejiang, Jiangxi, and Hubei, it performed well in 1988-90 adaptation and yield trials in early (ES) and late seasons (LS).

Average grain yield was 7.8 t/ha in

ES and 6.8 t/ha in LS. The highest yield of 11.2 t/ha was 10-15% higher than those of local check varieties. Average growth duration was 115-125 d in ES and 90-110 d in LS. In 1990, Zhe 8619 outyielded the hybrid rice check by 18.5% in ES and 4.3% in LS (Table 1).

Zhe 8619 is cold tolerant at the seedling stage and is resistant to blast and bacterial blight. No serious pests or diseases were observed in 1989-90. During the 1990 LS in Zhejiang and Jiangxi, bacterial blight attacked many rice varieties, but not Zhe 8619.

In 1990, the Zhe 8619 ratoon crop yield averaged 4 t/ha, 52% that of the main crop (7.7 t/ha). Ratoon crop duration was 56-61 d (Table 2).

Table 1. Performance of Zhe 8619 in yield trials in Xiantao, Hubei, China, 1990.

Yield components

Variety Duration Yield Increase

(d) (t/ha) over check Panicles Spikelets Fertility 1,000- Plant (%) (no./m2) (no./panicle) (%) grain ht

wt (g) (cm)

Early season Zhe 8619 116 7.7 18.5 375 128 81.2 29.7 101 Chang-You 48-2 115 6.5 390 117 50.3 28.9 90

(check)

Late season Zhe 86 19 91 7.2 4.3 290 112 79.2 29.5 95 Wei-You 49 96 6.9 - 269 114 69.9 29.1 89

(check)

Table 2. Ratoon rice yield and characteristics of Zhe 8619 in Xiantao, Hubei, China, 1990. a

Stubble Duration Plant Panicles Spikelets Fertility 1,000-grain Grain ht (cm) (d) ht (cm) (no./m 2 ) (no./panicle) (%) wt (g) yield (t/ha)

15 61 72 238 83 65.3 28.6 3.9 25 58 73 254 75 77.0 29.1 4.1 30 56 65 330 77 60.6 29.5 4.3 40 56 72 259 68 79.0 29.7 4.0

a Plot = 4 m 2 (2 × 2 m), 13- × 20-cm spacing.


Zhe 852, a short-duration, hig h-yielding rice variety for double-cropped areas in China

Jin Qingsheng, Qiu Boqin, and Lu Rubi, Crop Institute, Zhejiang Academy of Ag- ricultural Sciences, Hangzhou 310021, China

More than 70% of the total Yangtze River rice area in China is double- cropped.

variety, was developed by irradiating Zhefu 802/Suweon 290 F 1 seeds with 30,000 r units of Cs 137 gamma rays. After 2 yr in regional national tests, it was released in Oct 1990 as a high-yielding

Zhe 852, a short-duration semidwarf

variety with multiple resistances and wide adaptability.

In transplanting experiments during 1987-89, average grain yield was 6-6.7 t/ha, 11 % higher than that of the local check (Table 1). Zhe 852 is becoming popular among Yangtze River area farmers because of its high yield potential and short growth duration. It is resistant to blast and moderately resistant to bacterial blight and whitebacked planthopper.

Zhe 852 is 80 cm tall with intermediate tillering ability and 104-116 d duration (Table 2). It is awnless, medium-grained, with fully exserted panicles. It has 71.4% milling recovery, 25.1 % amylose, 9.4% protein content, and acceptable cooking and eating quality.

Table 1. Grain yield and duration of Zhe 852 in trials at different sites in China, 1987-89.

Zhe 852 Check Increase Site over check

Duration Yield Designation Duration Yield (%) (d) (t/ha) (d) (t/ha)

Hangzhou, Zhejiang Xiangtan, Hunan Xingjian, Jiangxi

Mean Hangzhou, Zhejiang Henyang, Hunan

Wuhan, Hubei Wuzhou, Jiangxi Heifei, Anhui

Mean Wengzhou, Zhejiang Changsha, Hunan

Wuhan, Hubei Yichung, Jiangxi Jianyang, Fujian

Mean

114 106 112 111 108 106

111 104 105 107 113 108

114 116 113 113

5.5 7.7 7.1 6.7 6.0 8.3

7.7 6.1 5.5 6.7 5.4 5.9

7.5 5.4 5.9 6.0

1987 Erjiufeng Zhefu 802 Zhefu 802

Zhuxi 26 Zhefu 802

1988 Yuanfengzao Zhuxi 26 Zhefu 802

Zhuxi 26 Zhuxi 26

Zhefu 802 Zhuxi 26 Zhuxi 26

1989

114 105 110 110 109 106

111 103 104 107 112 114

113 118 117 115

5.1 6.7 6.3 6.0 5.5 7.2

7.1 5.5 4.8 6 .0 4.6 5.7

6.7 4.3 5.7 5.4

8 16 12 12 9

16

8 10 14 12 17 4

10 24 4

12

Table 2. Morphoagronomic characteristics of Zhe 852 at different sites in China, 1989.

Duration Plant Panic1e Grains Fertile grains Sterility 1,000- Site (d)

(cm) (cm) ht length (no./panicle) (no./panicle) (%) grain

Hangzhou, Zhejiang Changsha, Hunan Wuhan, Hubei Nanchang, Jiangxi Wuhu, Anhui Jianyang, Fujian Zhejiang, Jiangsu

Mean

110 75 17.5 108 83 18.5 114 78 17.0 113 76 17.3 114 81 17.7 113 77 17.1 116 87 18.6

113 80 17.7

74 83 77 61 69 69 91

75

62 60 65 47 58 61 83

62

15.9 24.0 28.4 23.4 15.1 25.0 23.3 23.2 15.0 24.8 11.2 21.9 9.3 25.5

16.9 24.0

Kanakam (MO 11), a high- yielding, semitall variety from Kerala, India

N. R. Bai, R. Devika, C. A. Joseph, A. Regina, and S. L. Kumary, Rice Research Station, Moncompu, India

Kanakam is a medium-duration, red- kerneled variety with medium-bold grains derived from the cross IR 156 /Ptb 33. It was released in 1990 for cultivation during the three seasons of Kerala: virippu (Apr-May to Aug-Sep), mun- dakan (Sep-Oct to Dec-Jan), and puncha (Dec-Jan to Mar-Apr).

Kanakam performed well in multilocation trials from 1984 to 1987 (see table).

It is resistant to brown planthopper, blast, and rice tungro disease, and moderately resistant to stem borer, gall midge, and bacterial blight.

Yield performance of Kanakam in Kerala, India.

Grain yield (t/ha)

Kanakam Check variety b

Trial a

Rice Research Station (RRS) 4.8 3.4

Multilocational trial 1984-85 3.6 3.6 All India Coordinated Yield Trials

BPHRVT b 1985 4.7 3.3 BPHRVT I986 5.2 3.7

Farm trials, 1987-89 4.4 3.4 Operational Research Project 6.1 5.8

Moncompu, 1984-87

(ORP) trials, 1987-89

a Check variety was Jyothi at Moncompu RRS and MLT, Rasi for BPHRVT 1985, Vikas for BPHRVT 1986, and Pavizham for farm and ORP trials. b Brown planthopper resistant variety trial.

Space limitations prevent IRRN from publishing solely yield and yield component data from fertilizer field trials that are not conducted for at least two cropping seasons or at two differing sites. Publica- tion of work in a single season or at one site is limited to manuscripts that provide either a) data and analysis beyond yield and yield components (e.g., floodwater parameters, microbial populations, soil mineral N dynamics, organic acid concentrations, or mineralization rates for organic N sources), or b) novel ways of interpreting yield and yield component data across seasons and sites.


wt (g)

Integrated germplasm improvement-upland

Performance of upland breeding lines and germplasm under periodic moisture stress in erosion- susceptible soil

S. Pramanik, S. Gupta, and M. Arraudeau, Zonal Adaptive Research Station, Krish- nagar, Nadia, West Bengal, India

We compared 48 advanced upland rice breeding selections, IRRI germplasm, and traditional cultivars from northeastern India with six recommended upland rice cultivars.

Soil had pH 6.8, light to medium texture (Gangetic alluvial zone), and moderate slope, making it susceptible to erosion. It had low water retention and was deficient in N, organic matter, and P.

The experiment was laid out in simple observational plots of three, 1.5-m rows/ line, 20 cm apart. Rice was direct seeded 13 May 1988 and 18 June 1989. A 13-d dry spell delayed germination in 1988. Dry periods during tillering, booting, and

Some characteristics of 16 early- and medium-maturing entries under upland direct seeded condition in Krishnagar, summer 1988 and 1989.

Days to Plant Panicle length Weight of Panicles Plot Designaton heading height single (no./m 2 ) yield

(d) (cm) Mean ± SD panicle (g) (kg/ha)

Early group (<l00 d) GS Harin Kajli (traditional aus)

IR47697-2-F 4 -B-MLD27 Dumri (traditional aus) Dular (traditional check) IET6223 (check) CR237-1 (check)

Medium group (110-115 d) IR47697-2-F 4 B-MLD19 ARC7046

IR47701-79-B-1

Panke (traditional check) IET2233 (improved check) Rasi (improved check)

IR47697-2-F4 -B-MLD24

IR47701-79-B-14

IR47697-2-F 4 -MLD23

62 112.5 24.5 ± 1.36 53 60

95.7 19.7 ± 1.38

69 77.8 19.8 ± 2.13 77.0 20.5 ± 1.42

51 110.8 23.2 ± 1.82 52 117.0 24.3 ± 1.47 62 61

86.5 19.7 ± 1.59 98.0 24.5 ± 2.21

72 83.2 19.7 ± 1.24 76 110.7 22.7 ± 1.72 79 111.0 23.5 ± 2.34 78 105.3 22.5 ± 1.86 74 78.7 24.2 ± 1.43 76 116.0 22.2 ± 1.73 74 78

79.3 20.5 ± 1.68 82.7 23.6 ± 1.82

3.5 1.8 2.4 2.3 2.3 1.8 2.3 1.8

2.6 2.3 2.3 2.4 2.4 1.9 3.2 2.7

346 385 320 280 340 460 480 300

388 368 464 382 434 264 220 324

4.1 3.1 2.6 2.9 2.6 3.2 2.8 2.5

4.0 3.6 3.2 3.0 2.9 2.9 2.8 2.5

flowering stages also stressed test entries. groups (<l00 d and 100-115 d). Data Rainfall was evenly distributed during were collected on the best entries (see vegetative and reproductive phases in the table). Short-duration lines are generally 1989 experiment. preferred because an August harvest

Lines were divided into two duration allows time for a wet season crop.

BR20 and BR21: promising upland rices for Bangladesh coastal region

S. K. Zaman, G. M. Panaullah, K. P. Halder, and N. I. Bhuiyan, Bangladesh Rice Research Institute (BRRI), Joy- debpur, Gazipur 1701, Bangladesh

In southeastern Bangladesh coastal areas, farmers typically grow one wet season rice crop. Land remains fallow the rest of the year because of high salinity. When the monsoons start early, farmers can grow short-duration, rainfed upland aus rice before the main crop, but this is rarely done.

We compared recently-released modern varieties (MVs) BR20 and BR21 with traditional varieties (TVs) in field experiments at Sonagazi station and in farmers’ fields.

BR20, BR21, Boilam, and Binnatoa seeds were line-sown at 50 kg/ha after the first monsoon rains in 1988 and 1989.

The top 5 cm of soil had electrical conductivity of 8-10 dS/m; the next 20 cm of soil, 2-5 dS/m.

We also conducted trials in farmers’ fields in 1989 at nine coastal district locations. BR20 and BR21 were compared with a locally popular TV (Kalimugi, Hashikalmi, or Chinal).

BR20 and BR21 outyielded TVs in both trials (Table 1). BR21 and the TVs matured in 95-98 d; BR20 matured in 108 d.

Table 1. Performance of BR20 and BR21 as rainfed upland rices compared with 2 popular local TVs. BRRI Regional Station, Sonagazi, Feni.

Grain yield a (t/ha)

1988 1989 Variety Days to maturity

Binnatoa 2.2 c 1.6 b 95 Boilam 1.9 d 1.7 b 97 BR20 3.0 a 3.0 a 108 BR21 2.7 b 2.8 a 98

a In a column, figures followed by a common letter do not differ significantly at the 5% level by DMRT.

Rice yield varied with farm location, perhaps because of soil salinity differences. BR20 and BR21 yielded higher (2.0-3.6 t/ha) than the TVs (1.0-2.0 t/ha) at all locations (Table 2).

Table 2. Performance of BR20 and BR21 as rainfed upland rices compared with locally popular TVs in farmers’ fields in 3 coastal districts.

Site Grain yield (t/ha)

BR20 BR21 TV a

Feni district Dagonbhuiya 3.6 3.0 1.8 (Kalimugi) Parshuram 3.1 3.0 2.0 (Hashikalmi) Chagalniya 2.5 2.0 1.3 (Chinal) Motiganj 3.0 2.5 1.5 (Binnatoa)

Laxmipur Laxmipur Sadar 3.2 3.3 1.5 (Boilam) Ramganj 3.5 3.1 Ramgoti 3.0 3.0

Noakhali Senbug 2.0 2.6 Companiganj 2.7 3.1

a Name of TV in parentheses.

1.5 (Kalimugi) 1.0 (Chinal)

1.4 (Binnatoa) 1.5 (Boilam)


CROP AND RESOURCE MANAGEMENT Fertilizer management—inorganic sources Long-term effects of nitrogen, phosphorus, and design with four replications. potassium on irrigated N as prilled urea (80 kg N/ha) was lowland rice in Mekong applied in three equal splits at planting, Delta tillering, and panicle initiation. P as

was laid out in a randomized block

superphosphate (17.6 kg P/ha) and K as P. S. Tan, T. N. Anh, and N. V. Luat, muriate of potash (25 kg K/ha) were Cuu Long Delta Rice Research Institute basally applied. (CLRRI), Omon, Haugiang, Vietnam Averaged over 5 yr, rice yield was

We studied the long-term effects of NP for both seasons (see table). Single N NPK on irrigated lowland rice IR64. or P gave more yield than single K. The clay soil had pH 5.2, 0.3% total N, Grain yield was higher with P applied in 4.1 mg available P/100 g, and 0.74 meq wet season (WS) than in dry season (DS) exchangeable K/100 g. The experiment because 2-3 mo before WS the soil was

highest with NPK, followed by that with

Effects of NPK on grain yield of IR64, CLRRI, Haugiang, Vietnam, 1986-90.

Treatment Grain yield a (t/ha)

Dry season Wet season

N Check (no fertilizer) 3.1 d 2.4 de

P 3.4 c 3.5 b K NP NK 3.9 b 2.6 cd PK NPK a Av of 5 crop seasons. In a column, means followed by a common letter are not significantly different at the 5% level.

3.8 b 2.8 c

3.3 cd 2.2 e 4.4 a 4.3 a

3.3 c 3.4 b 4.6 a 4.5 a

dry; 3-4 mo before DS, it was flooded. P also enhanced the effectiveness of N on yield during WS.

Effect of potassium application levels and time on rice

E. K. Syriac, P. P. Joy, N. P. Nair, D. Girija, and C. A. Joseph, Rice Research Station, Moncompu, Thekkekara 688503, Kerala, India

We evaluated three K levels and five application times in an experiment to

Grain and straw yields of rice as influenced by K level and time of application. Kerala, India, 1989- 90.

maximize grain yield and minimize disease in transplanted lowland rice.

The experiment was laid out in a randomized block design with 16 treatments and three replications during monsoon (Jun-Oct) 1989 and 1990 and wet season (WS) (Nov-Mar) 1989-90.

The soil was hydromorphic silty clay with pH 5.0, electrical conductivity 0.1 dS/m, 0.57% organic C, 16.8 kg available P/ha, and 111 kg available K/ha. MO- 11 (120 d) was transplanted at 15- × 15-cm spacing. P was basally applied at 20 kg/ ha; N in three splits at 90 kg/ha; and K as

basal (B) at planting, at maximum tillering (T), and at panicle initiation (PI).

Treatments had no statistically significant effects on grain yield during WS. Time of K application significantly increased grain and straw yields during monsoon, with K applied at B + T yielding the most grain (2.7 t/ha). There was no statistical difference among K levels with respect to grain yield (see table).

The increase in rice yield (Y) to K treatment fitted a quadratic response: Y = 2.19 + 0.015 K - 0.00015 K 2 .

1989 and 1990 kharif a

Treatment Grain Straw Fertilizer management—organic sources (t/ha) (t/ha)

K level (kg/ha) 25 50 75

LSD (0.05)

B Time

B+T B+PI T+PI B+T+PI

LSD (0.05)

Interaction K level × time Control mean Treatment mean Control vs treatment a Pooled mean.

2.5 2.6 2.5 ns

2.4 2.1 2.6 2.4 2.5 0.2

ns 2.2 2.5 sig

2.9 3.1 3.1 ns

3.1 3.2 3.0 2.9 3.1 ns

2.4 ns

3.1 sig

Effect of vitamins on spore germination and viability of Azolla microph ylla sporocarps

R. Shanmugasundaram and S. Kan- naiyan, Biotechnology Unit, Agricultural Microbiology Department, Tamil Nadu Agricultural University, Coimbatore 641 003, Tamil Nadu, India

Azolla normally reproduces vegetatively. When conditions are adverse, however, sexual reproduction also occurs. The

Azolla sporophyte is heterosporous, producing both megasporocarps and microsporocarps in the same plant.

A. microphylla spore germination. Sporulating A. microphylla were heaped and covered with a 10% clay soil slurry. Heaps were periodically sprinkled with water and allowed to partially decom- pose. After 3-4 wk, the heaps were spread uniformly and dried in shade.

Dried Azolla sporocarps (dried frond-based spore inoculum) were soaked in water for 12 h, then sieved.

We studied the effect of vitamins on


Megasporocarps and microsporocarps were handpicked, mixed at a 1:2 ratio, and sterilized for spore germination under in vitro conditions.

Spores were centrally placed in petri dishes containing sterile NO 3 solid medium. We added 2-3 ml of vitamins (ascorbic acid, vitamin B1, pantothenic acid, nicotinic acid, and riboflavin, each at 25 ppm) and incubated the plates under 1500-2000 lux light.

All vitamins tested stimulated mega- spore germination (Table 1). Germina- tion and fertilization were higher with nicotinic acid and riboflavin.

In a survival study, dried sporocarps that had been stored in burlap bags for 1, 2, and 3 yr were presoaked separately for 12 h in growth regulator GA 3 and systemic fungicide carbendazim (both at 100 ppm). These were released into soil extract medium. Another batch of sporocarps was presoaked in a combined solution before release.

Some sporelings developed from all three storage groups (Table 2). Spores stored for 1 yr survived better than older spores, regardless of the soaking solution. Spores from treated sporocarps had improved germination.

Table 1. Effect of vitamins on A. microphylla spore fertilization.

Vitamins Fertilization (% Increase (%) (25 ppm) emerged sporelings) over control

Ascorbic acid 49.68 38.19 Vitamin B 1 54.46 51.49 Pantothenic acid 56.88 58.22 Nicotinic acid 65.96 83.48 Riboflavin 63.75 77.33 Control 35.95

CV 24.01

Table 2. Studies on the viability of frond-based spore inoculum of A. microphylla stored in burlap bags.

Presoaking solution Sporelings that emerged a

(no./tub)

1 yr old 2 yr old 3 yr old (100 ppm)

GA 3 217.50 13.50 - Carbendazim 75.50 19.00 2.50 GA 3 + carbendazim 220.50 3.50 0.50 Control 146.00 7.00 2.50

CV 12.21 a Each 5-g dried spore inoculum used 300 megasporocarps. This was constant for each treatment tested.

Use of rice straw under submerged conditions

B. Singh, Soil Science and Agricultural Chemistry Department (SSACD), CSA University of Agriculture and Technology (CSAUAT), Kanpur 208002; O. P. Srivastava, SSACD, BHU, Varanasi; and R. M. Upadhyay, SSACD, CSAUAT, Kanpur 208002, India

We studied the feasibility of applying fresh rice straw under submerged conditions to rice variety Jaya during the 1983 kharif (monsoon) and 1984 wet season (WS).

Soil was loamy with pH 7.8, 0.43% organic C. Available NPK were 181, 6.6, and 152 kg/ha. We incorporated 5 and 10 t straw with and without additional N. A uniform dressing of 26 kg P and 49 kg

K/ha was applied. Straw was incorporated 21 d before transplanting.

Grain and straw yields increased significantly with rice straw incorpora- tion (Table 1). Yield and N uptake were best with 5 t rice straw and 100 kg N/ha applied together.

We examined N mineralization rate in normal (pH 7.8) and sodic (pH 10.1) soils under submerged conditions in the laboratory. Ammoniacal N content was less in sodic than in normal soil (Table 2). This was related to soil organic C content.

In both soils, N content increased up to 30 d, then decreased. Adding rice straw accelerated the mineralization rate. Maximum NH 4 -N content (53.5 ppm) was with 200 ppm fertilizer N and 10 t rice straw/ha.

Table 1. Effect of N fertilizer and rice straw on yield and N uptake by rice plants.

Treatment

Control 5 t rice straw 10 t rice straw 100 kg N (urea) 100 kg N (urea) + 5 t

rice straw 100 kg N (urea) + 10 t rice

LSD (0.05) straw

1983

Yield (t/ha) N uptake (kg/ha)

Grain Straw Grain Straw

2.3 4.6 36.7 28.2 3.3 5.7 43.3 35.1 3.3 5.8 44.0 36.6 4.1 7.1 55.3 46.6 4.4 7.6 59.6 50.2

4.4 7.7 60.0 50.6

0.2 0.4 3.0 2.8

1984

Yield (t/ha) N uptake (kg/ha)

Grain Straw Grain Straw

2.5 4.2 33.1 25.6 3.0 4.8 39.7 29.9 3.1 5.0 41.0 31.6 3.8 6.4 51.2 41.6 4.1 7.0 55.7 46.2

4.1 7.1 56.1 46.9

0.2 0.4 2.6 2.5

Table 2. Effect of rice straw on NH 4 -N release under submerged condition in normal and sodic soils.

NH 4 -N (ppm)

Treatment Normal soil Sodic soil

15 d 30 d 45 d 60 d 15 d 30 d 45 d 60 d

Control 10.8 12.1 9.1 5.2 8.0 9.4 Rice straw (10 t/ha) 13.7 14.0

5.3 3.0 9.8 5.6 11.1 13.7

Fertilizer N (200 ppm) 38.0 43.3 7.6 3.7

28.4 11.1 13.7 26.4 15.4 5.7 Fertilizer N (200 ppm) 45.8 53.5 35.0 12.6 26.6 31.2 18.8 6.1

+ rice straw (10 t/ha)

Mean 27.07 30.72 20.57 8.62 17.35 20.17 11.77 4.62

Integrated pest management—diseases Managing rice sheath blight We evaluated the efficacy of two (ShB) using fungal antagonists antagonistic fungi (Trichoderma and organic amendments longibrachiatum [Tl] and Gliocladium

virens [Gv]) and two organic manures K. Manibhushanrao and U.I. Baby, Centre ( Gliricidia maculata leaves and for Advanced Studies in Botany, University Azadirachta indica [neem] cake), both of Madras, Guindy Campus, Madras individually and combined, to control 600025, India ShB caused by Rhizoctonia solani.


Experimental plots (1 m 2 ) were arranged in a randomized block design with three replications at the Madras University Field Research Laboratory, Maduravoyal, Tamil Nadu, during monsoon 1989 and wet season 1989-90. The clay soil had 7.3 pH and 42% water-holding capacity.

Plots were artificially infected with R. solani. We incorporated the antagonists and amendments into the soil as a wheat bran/sawdust preparation at 0.5 g/kg soil.

Highly ShB-susceptible TKM9 seeds were direct sown after incubating for 1 wk. Overcrowded seedlings were thinned at 20 d to get approximately 20- x 20-cm spacing. Urea, super-

phosphate, and muriate of potash were split-applied to maintain the NPK level (100-50-50 kg/ha).

Disease incidence was scored using the Standard evaluation system for rice (SES).

Both antagonists and amendments— alone and together—significantly decreased ShB intensity and increased grain yield (see table). Amendments protected plants better than antagonists: gliricidia was the best, yielding 42% protection over the control. System integration helped both antagonists to more effectively control ShB.

Gliricidia + Gv increased grain yield the most. There was little variation in straw yield. 1. SDS (12%) polyacrylamide slab gel showing

A) marker protein, B) 37kDa coat protein (CP) C) 24 kDa noncapsid protein (NCP), D) extracts from RGSV infected rice leaves, and E) healthy rice leaves.

2. Purified noncapsid protein showing needle-like crystals under phase contrast microscopy.

Effect of fungal antagonists and organic amendments on rice yield and ShB intensity in Maduravoyal, Tamil Nadu, India. a

Treatment

Control Gliricidia Neem G. virens (Gv) T.longihrachiatum (Tl) Gliricidia + Gv Gliricidia + Tl Neem + Gv

Grain yield (t/ha)

3.0 f 3.6 ef 4.6 bcd 3.9 de 4.4 cde 5.9 a 5.7 a 5.4 ab

Straw Disease yield incidence (/tha) (%)

5.3 bc 15.11 a -5.5 abc 8.71 b 5.4 bc 8.99 b 5.2 c 9.27 b 5.0 c 9.47 b 6.2 a 7.4 b 5.8 ab 6.66 b 5.6 abc 8.15 b

Protection (%) over control

42.4 40.5 38.6 37.3 49.4

46.1 55.9

Neem + Tl 5.3 abc 5.5 abc 7.29 b 51.8 a Values followed by the same letters are not significantly different (p = 0.01) by Duncan's multiple range test.

Detecting and purifying noncapsid protein in rice infected with grassy stunt virus (RGSV)

G. J. Miranda and H. Koganezawa, Plant Pathdogy Division, IRRI

RGSV is classified as a tenuivirus. This virus group produces noncapsid protein (NCP), but evidence that RGSV produces NCP is lacking.

We detect NCP in RGSV-infected rice leaves—but not in healthy ones—by using sodium-dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) Fig. 1). We purified NCP by solubiliz- ing and crystallizing it at differential pH in a citrate phosphate buffer and finally by ultracentrifuging.

NCP dissolved at a pH greater than 7.O and recrystallized at a pH lower than


6.0. It occurred as needle-shaped crystals as reported in maize stripe, rice stripe, and other tenuiviruses. We obtained many needle-shaped crystals 1.8-9.6 µm long and 0.04-0.4 µm wide in purified extracts from RGSV- infected leaves (Fig. 2).

NCP has a single protein with a molecular weight (MW) of 24 kDa and its coat protein has a MW of 37 kDa (Fig. 1). The purified NCP had a typical protein absorption spectrum with maximum absorbance at 278, minimum absorbance at 252, and 0.6 absorbance ratio (A 260 / 280 ).

100 g tissue. The NCP of RGSV was very similar to what other tenuiviruses produce, except that it has a slightly higher molecular weight and lower solubility in low-ionic-strength buffer at pH 7.0.

We obtained a yield of about 20 mg/

Estimation of rice bacterial sheath brown rot (BSR) and rice blast (Bl) severity in five Burundi highland swamps

J. F. Detry, Phytopathology Department, ISABU; J. P. Chapeaux and J. P. Tilquin, Department of Crop Improvement, Faculty of Agronomy, University of Burundi, Bujumbura, Burundi

Highland swamps (1,200-2,000 m elevation) represent 10% of Burundi's arable land. Rice (Yunnan 3) is grown during the rainy season. BSR, caused by Pseudomonas fuscovaginae, and Bl, caused by Pyricularia grisea are two

major diseases. Diversifying rice varieties is crucial in controlling these diseases.

replications each, Oct 1987-May 1988 at five sites representative of Burundi’s swamp environmental types (see table).

Temperatures below 15°C were aggregated during three stages: transplanting to booting, booting to flowering, and during maturation. We evaluated BSR and Bl on the mature tillers of 10 plants randomly selected from each plot.

The Muramba site benefited most from favorable climate (see table). At Ndebe, the temperature frequently dropped below 15°C. Temperatures were lowest during tillering (Jan to mid-Feb) but rose progressively until maturity (mid-Mar to end Apr).

We compared 24 varieties, with four

Efficacy of Beauveria bassiana combined with various stickers or spreaders against rice hispa (RH)

K. C. Puzari and L. K. Hazarika, Mycol- ogy Research Section, Assam Agricul- tural University, Jorhat 785013, Assam, India

RH Dicladispa armigera Olivier (Cole- optera, Chrysomelidae) attacks summer rice in areas around Assam with high relative humidity and average rainfall of 2,500-4,500 mm. An effective biocontrol agent is B. bassiana (Bals.) Vuill, but it is not practical to apply conidial suspen-

Effect of B. bassiana mixed with different stickers and spreaders on rice hispa adults.

Treatment Mortality (%) a

Water + B. bassiana 51.89 (46.06)

Teepol + B. bassiana 81.48 (64.48)

Triton-AE + B. bassiana 74.08 (59.40)

Tween 80 + B. bassiana 96.30 (79.30)

Sandovit + B. bassiana 81.48 (64.55)

Hamam + B. bassiana 93.26 (75.03)

3.84 5.32

LSD (0.05) (0.01)

a Data in parentheses represent angular transformed values which were analyzed.

Cultivation type and BSR and Bl severity at 5 Burundi sites.

Disease severity a Hours (no.) of temp below 15ºC Site Altitude Cultivation

(m) type BSR Bl Tillering Booting Maturation

Akagoma 1 1560 Groundwater 11.5 1.9 414 119 49 Akagoma 2 1560 Flooded 37.1 7.8 414 119 49 Kobero 1390 Flooded 5.3 20.0 109 68 23 Muramba 1370 Groundwater 6.3 4.9 9 6 4 Ndebe 1540 Flooded 6.1 2.7 5 64 25 1 199 a Mean of 24 varieties (%) scored by these scales: BSR — 0 = panicles correctly emerged, 1 = less than 1/3 of panicle blocked, 2 = 1/3 - 2/3 of panicle blocked, 3 = more than 2/3 of panicle blocked. Bl — 0 = healthy panicles; 1 = blackened neck, less than 1/3 unfilled grains; 2 = blackened neck, 1/3 - 2/3 unfilled grains: 3 = blackened neck, more than 2/3 unfilled grains.

Severity coefficient = 3 × sum of scores

number of tillers × 100

BSR developed after booting, when appeared during booting. Nodal Bl at the bacteria tend to multiply rapidly. The maturity was most severe at Kobero. severity coefficient of blocked panicles The climatic parameters noted do not was highest (37.1%) at Akagoma 2 and sufficiently explain the severity of BSR moderate at Ndebe. and Bl incidence. Future studies need to

except at Akagoma 2 and Ndebe, where it the leaf areas, and soil fertility. We noted Bl on leaves during tillering, measure temperature, relative humidity in

sions to large fields because of heavy rains.

combined with some stickers and spreaders for RH control.

Conidial suspensions (1 ×10 7 conidia/ ml) were mixed separately with Sandovit (Agril. wetting agent), Triton-AE (uni- versal spreader sticker), Teepol B-300 (liquid detergent), Tween 80, and Hamam toilet soap, all at 0.23 g/liter concentra- tion.

We evaluated efficacy of B. bassiana

We used an atomizer with 6 ml of the suspension on rice seedlings in plastic pots. The seedlings were air-dried 30

min, then confined with 20 RH adults (4 d old) that had been starved for 6 h.

Sticker/spreader treatments in water were dispensed four times until runoff at 8-h intervals for 5 d. Seedlings sprayed with water mixed with stickers and spreaders without B. bassiana served as control.

Mortality percentages were recorded on the 10th day after inoculation. In the control, adult deaths were around 10% (see table).

Tween 80 and Hamam were the best compatible sticker/spreader with B. bassiana against RH.

Integrated pest management—insects Mating sequence of rice leaffolder (LF) Marasmia patnalis Bradley

N. P. Castilla and Z. R. Khan, ICIPE- IRRI Project, IRRI

The mating sequence of the 3- to 4-d-old LF under a reversed cycle—12 h scoto- phase, 12 h photophase—served as basis for a bioassay of identified sex phero- mone compounds. Forty same-age pairs were observed.

Mating activities in M. patnalis commenced when the females assumed

the calling position: curving the abdomen dorsally and expanding the wings (see figure, a). The responsive male engaged in random flight, and vigorous antenna and wing vibration (figure, b). The male approached the calling female and tapped her wings with his antennae and foretarsi during courtship (figure, c).

The male then attempted copulation by approaching the female from behind (figure, d). Placing his antennae and foretarsi on the female’s wings, he extruded his clasper and curved his abdomen ventrally until the clasper touched the female's abdominal tip


(figure, e). The receptive female re- mained quiescent, lifted her wings, and further curved her abdomen (copulatory acceptance posture) (figure, d). After the female accepted the male, the pair immediately turned 180° (figure, f), hung upside down for a second (figure, g), and landed on a substrate, assuming a posterior-to-posterior copulation orienta- tion. Unless the pair was disturbed,

mating was quiescent; wing movement and antenna vibration ceased (figure, h).

Aside from the sex pheromones females released during calling, both sexes most likely release other olfactory and tactile stimuli for copulation to occur. Further investigations are necessary to verify these stimuli and identify their specific functions.

Diagrammatic representation of M. patnalis mating sequence.


Population fluctuation of leaffolder (LF) at different planting times in some rice varieties

Ch. Chiranjeevi, G. M. Rao, Rice Research Unit (RRU), Bapatla, Andhra Pradesh (AP), India

Rice LF Cnaphalocrocis medinalis is a serious pest in Andhra Pradesh when planting extends from Jul to mid-Sep because of varied rainfall.

times on LF incidence in BPT2740, BPT11978, MTU6861, MTU2400, and MTU7029.

Varieties were planted in a split-plot design with three replications. No insecticide was used. Total leaves and damaged leaves were counted on 20 randomly selected hills/plot, 60 d after transplanting.

LF damage increased significantly with delayed planting date. There was no difference in damage among the varieties (see table).

Effect of planting time on LF incidence. RRU, Bapatla, AP, India, 1986-87 kharif.

Planting Damaged leaves a

time (%)

15 Aug 1986 37.730 Aug 1986 47.8 15 Sep 1986 57.3 30 Sep 1986 64.8

Mean LSD 1.9

We studied the effect of four planting

a Values are angular transformations.

Survey of ricefield insects in Mbo and Ndop Plains of Cameroon

C. T. Asanga, Institute of Agronomic Research, B.P. 44, Dschang, Cameroon

Rice is mainly produced in the northern Sahelian Region of Cameroon. The rest is cultivated in the Western Highland Savanna, mainly in the Mbo and Ndop Plains, with an estimated 210 ha and 3,000 ha of irrigated rice, respectively.

During the 1987-89 survey, we collected and documented insect species

present, identified insect damage, and documented beneficial insects.

Insects were collected from an advanced yield trial plot (1,080 m 2 ) sur- rounded by other irrigated ricefields.

12 day) from transplanting to crop maturity. Collections were from late Jul to early Nov in Ndop and late Sep to mid-

We collected 24 times (12 night and

Dec in Mbo. A hurricane light trap centrally installed collected noctuids from nightfall to dawn (11h). Day collections were made at 11:00 a.m. with sweep net.

We collected over 40 insect species during the 2-yr survey. The table lists the 20 most prevalent species.

Relative prevalence of 20 insect species collected from irrigated plots in 2 rice-growing areas in Cameroon.

Relative prevalence a (%)

MBo Ndop Common and scientific name Remarks

Stalk-eyed borer - Diopsidae: 18.3 33.4 A major rice stem borer Diopsis macrophthalma (Dalman) Rice bug - Alydidae: Leptocorisa 10.1 1.8 Feed on ripening rice grain

oratorius (Fabricius) Brown stink bug - Pentatomidae: 8.9 1.3 Predaceous on several insects

Euschitus servus (Say) and also plant feeders Cixiid planthoppers - Cixiidae: 8.7 39.2 Can spread virus

Oecleus sp. Long-horned grasshoppers - 8.2 5.4 Predators of rice bugs and stem

Tettigoniidae: Conocephalus sp. borer eggs; also leaf feeders Black lady beetles - 6.6 0.1 Predators of many insects, esp.

Coccinellidae: Hippodamia sp. soft-bodied ones Short-horned grasshoppers - 6.0 0.2 Plant feeders

Acrididae: Atractomorpha sp. Spine-tailed earwigs - 4.0 0.2 Nocturnal plant feeders

Forficulidae: Doru sp. Green stink bugs - Pentatomidae: 3.5 Feed on rice grain during milky,

Nezara viridula (Linn.) soft dough, and hard dough stages

Cereal leaf beetle-Chrysomelidae: 3.4 0.3 Foliage feeders

Shield-backed bugs - Scutelleridae: 3.4 0.3 Known to be plant feeders,

plants was not described.

Oulema sp.

Pharocosis annulus but feeding activities on the rice

Differential grasshoppers - Acrididae: 3.0 0.2 Very destructive foliage feeders

Seed bugs - Lygaeidae: Eromocoris ferus 2.7 1.4 Feed on seeds

Sugarcane borer - Pyralidae: Diatraea 0.2 Minor stem borer of rice in the

Melanoplus differentialis (Thomas)

(Say)

sacchardis (Fabricius) area Rove beetles - Staphylinidae: Paederus 1.9

grandis (Aust.) Harlequin bugs - Pentatomidae: 1.9

Murgantia histrionica (Hahn) African mole crickets - Gryllotalpidae: 1.4

Gryllotalpa africana Palisot de Beauvois

Known to be predaceous

Found in ricefields, but feeding

Cut plants at base and feed on habit was not described.

young roots, problem in

Using chlorpyrifos to control gall midge (GM)

S. Srinivasan, M. R. K. Reddy, and P. R. Reddy, Agricultural Research Station, Nellore 524004, Andhra Pradesh, India

Efficacy of foliar spraying and seed soaking with 0.05% and 0.1 % chlorpyrifos to control GM Orseolia oryzae in rice nurseries was evaluated during the 1988 wet season.

Seven treatments (see table) replicated four times were arranged in randomized complete block design. We sowed on 28 Aug in 1- × 1-m plots.

Tikkana (NLR27999) seed was soaked in chlorpyrifos solution for 12 h, then incubated for 36 h; sprouted seed was soaked for 3 h. Seed for the foliar spray treatment and control was soaked in water and incubated. Chlorpyrifos was sprayed 10 d after sowing (DAS).

We assessed percent GM incidence (exposed silver shoots and suppressed galls) by randomly pulling 200 seedlings per treatment at 10-d intervals from 25 DAS onwards.

differences at 25 and 35 DAS. Insecti- cidal efficacy was not significant at 45 DAS (see table). Chlorpyrifos treatments

GM incidence in the nursery with chlorpyrifos treatments.

Treatments showed significant

GM incidence a (%)

25 DAS 35 DAS 45 DAS Treatment

T1 Foliar spray of chlorpyrifos 0.05% at 10 DAS

T2 Foliar spray of chlorpyrifos 0.1 % at 10 DAS

10.5 17.7 37.8 (18.8) (24.7) (37.8)

6.0 21.8 24.7 (14.1) (27.2) (29.6)

unflooded fields T3 Soaking of seeds in 10.6 Red shouldered stink bugs - Pentatomidae: 1.1 0.4 Feed on plant, but not chlorpyrifos 0.05% (18.9)

economically important T4 Soaking of sprouted 17.2 Ground beetles - Carabidae: Colosoma 1.1 0.2 Known to be omnivorous, but seeds in chlorpyrifos (24.3)

Thyanta sp.

scrutator (Fabricius) activities in the ricefields 0.05% were not observed. T5 Soaking of seeds in 7.1

species T6 Soaking of sprouted 17.7 Damsel bugs - Nabidae: Nabis sp. 0.0 0.1 Predaceous on several insect chlorpyrifos 0.1% (15.4)

seeds in chlorpyrifos (24.7)

(29.4) Total no. = Total count for the 12 day sweeps plus the 12 light trap collections per year. LSD (P=0.05) 4.27

Intensities reported are 1988 and 1989 averages. CV (%) 13.77

28.8 (32.4) 40.7

(39.4)

23.3 (28.2) 36.9

(37.4) Total no. of each species

.. a Relative prevalence % = × 100

0.1% Total no. of all species T7 Untreated check 24.2 41.6

(40.1) 8.06

16.49

38.0 (37.9) 23.2

(28.7)

37.5 (37.6) 36.3

(36.5)

33.5 (33.3) ns b

13.34

a Figures in parentheses are angular transformed values. b Nonsignificant by F test.


-

-

-

-

-

did not adversely affect germination; nor were they phytotoxic.

Seed soaking and foliar spraying were superior to sprouted-seed soaking treatments in surpressing GM at 25 DAS. In some treatments, this trend persisted up to 35 DAS.

Influence of some weather factors on rice stem borer (SB) infestation

S. Ramakrishnan and M. S. Venugopal, Horticultural Research Station, Tamil Nadu G.D. Naidu Agricultural Univer- sity, Udhagamandalam 643001, Tamil Nadu, India

Deadheart/whitehead (DH/WH) incidence was recorded weekly during 1988-89 at the Rice Research Station, Tirur. Mean weather parameters 14 d before the observation date [maximum temperature (ºC) ( X 1 ), minimum temperature (ºC) ( X 2 ), relative morning humidity (%) ( X 3 ), and rainfall (mm) (X 4 )] were correlated with DHWH incidence.

The fitted multiple regressions to predict DH and WH damage were Y = 1.2754 + 0.0913 X 1 – 0.04843 X 2 + 0.1067 X 3 + 0.2934 X 4 and Y = 13.9020

0.0318 X 4 , respectively. The regression equations explained approximately 50% variation in DH/WH damage due to weather, but none of the factors significantly contributed to SB infestation. Instead, continuous cropping allows the pest to multiply.

–0.0336 X 1 – 0.0933 X 2 – 0.0980 X 3 –

Mirid predation on brown planthopper (BPH) eggs

I. Manti, Sukarami Research Institute for Food Crops, P.O. Box 34, Padang, West Sumatra, Indonesia

We observed Cyrtorhinus lividipennis predation on BPH eggs in an untreated IR1917-3-17 field during the 1987-88 dry season.

TN1 plants with BPH eggs were exposed in the field.


Chemical control of gall midge (GM) in the rice nursery

Incidence of GM in nursery at Agricultural Research Station, Nellore, India.

Treatment Incidence a (%)

25 DAS 40 DAS

S. Srinivasan and M. R. K. Reddy, Agricultural Research Station (ARS), Nellore 524004, Andhra Pradesh, India

GM Orseolia oryzae (Wood-Mason) damage causes seedlings to break while being pulled for transplanting. Popula- tions also build up in the nursery to attack the transplanted crop.

We studied the effect of soaking seeds in seven insecticides (0.1%) and of two granular insecticides on GM incidence in the nursery during the 1987 wet season.

We soaked Tikkana (NLR27999) seed in insecticidal solutions for 12 h, then incubated it for 36 h. Water-soaked seed was used in granular treatments and as a control.

Nursery plots of 1 × 1 m were laid out in a randomized complete block design with 17 treatments, replicated three times.

Granular and foliar insecticides were applied (see table). We randomly pulled 200 seedlings per treatment at 25 and 40 DAS to assess GM incidence.

40 DAS among treatments were significant. Incidence at 25 and 40 DAS was lowest in chlorpyrifos seed-soaking treatments. The other insecticides, used for soaking seed alone or in combination with foliar spraying at 25 DAS, did not protect rice from GM for 25 d.

We confirmed that chlorpyrifos seed soaking (0.1 %) combined with foliar spraying at 25 DAS controls GM for 40 d in the nursery.

Differences in GM incidence at 25 and

1 Soil application of 24.1 19.3 phorate 10 G at 1.25 (29.3) (25.8) kg ai/ha, 10 DAS

2 Soil application of carbo- 43.6 61.2 furan 3G at 1.25 kg ai/ha, (41.3) (51.5) 10 DAS

3 Seed soaking in mono- 52.0 64.2 crotophos 36 WSC (46.6) (53.4) at 0.1%

4 T3 + foliar spray of 48.5 64.6 monocrotophos at (44.1) (53.6) 0.05%, 25 DAS

chlorpyrifos 20 EC (22.6) (24.0) at 0.1%

6 T5 + foliar spray of 19.7 11.9 chlorpyrifos at 0.05%, (24.8) (20.0) 25 DAS

7 Seed soaking in 53.2 55.9 phosphamidon (47.0) (48.3) 85 EC at 0.1 %

8 T7 + foliar spray with 46.0 68.2 phosphamidon at 005%, (42.6) (55.8) 25 DAS

9 Seed soaking in quinal- 27.9 33.5 phos 25 EC at 0.1% (31.5) (35.0)

10 T9 + foliar spray of quinal- 28.1 43.4 phos at 0.05%, 2.5 DAS (32.1) (41.2)

11 Seed soaking in methyl 59.4 63.7 parathion 50 EC at 0.1% (50.9) (53.3)

12 T11 + foliar spray of 42.3 54.0 methyl parathion at (40.5) (47.3) 0.05%, 25 DAS

13 Seed soaking in formo- 48.8 55.1 thion 25 EC at 0.1% (44.2) (47.9)

14 T13 + foliar spray of 50.7 62.8 formothion at 0.05%, (45.4) (52.8) 25 DAS

15 Seed soaking in 61.1 58.4 demeton-S-methyl (51.5) (49.8) 25 EC at 0.1%

of demeton-S-methyl (51.6) (54.3) at 0.05%, 25 DAS

17 Untreated control 55.5 61.2 (48.2) (51.5)

LSD (P = 0.05) 12.30 10.28

5 Seed soaking in 14.9 17.5

16 T15 + foliar spray 60.7 65.7

CV (%) 18.09 13.71 a Figures in parentheses are angular transformed values.

Field predation by C. lividipennis in untreated IR1917-3-17 at different cropping periods. IRRI, 1987-88 dry season.

Days after BPH eggs Field predation Cyrtorhinus population transplanting exposed a by Cyrtorhinus per hill b (± SE)

35 0.25 ± 0.05

49 329.9 3.85 ± 0.98 0.29 ± 0.05

(no.) (% ± SE)

42 0.27 ± 0.04

56 0.42 ± 0.06 63 443.3 4.89 ± 0.77 0.63 ± 0.09 70 0.92 ± 0.11 77 562.3 8.06 ± 0.94 1.15 ± 0.12 84 0.82 ± 0.14 91 366.5 17.71 ± 2.57 1.25 ± 0.14 98 0.55 ± 0.08

a Av of 30 replications. b Collected by FARMCOP machine. SE = standard error at 95% probability.

Predation increased with the mirid population. It was highest 91 d after transplanting when the mirid population was 1.25/hill (see table).

Comparison of yellow stem borer (YSB) catch in light traps

S. Ramakrishnan and M. S. Venugopal, Horticultural Research Station, Tamil Nadu G.D. Naidu Agricultural Univer- sity, Udhagamandalam 643001, Tamil Nadu, India

We compared three traps for their relative efficiency in attracting YSB moths at the Tirur Rice Research Station during 1988- 89. We used a local bamboo light trap with 40-W incandescent bulb (LBL-T 40 W) and two modified Robinson light traps. One had a 125-W mercury vapor lamp (MRL-T 125 W), and the other a

200-W, incandescent bulb (MRL-T 200 W the least (4.7 moths/d). The MRL-T W). Traps were located at least 100 m 125 W captured 34.9% and the MRL-T apart. 200 W, 189.3% more moths than the

The MRL-T 200 W attracted the most LBL-T 40 W (see table). Differences moths (13.5 moths/d) and the LBL-T 40 were significant.

Attraction of YSB moths to MRL-T with 2 light intensities and to LBL-T.

Month Daily catch a (no.) of YSB moths

MRL-T 125 W MRL-T 200 W LBL-T 40 W

Apr 1988 18.6 (1.31) 60.6 (1.79) 42.9 (1.63)

Jun 2.0 (0.60) 0.7 (0.44) 0.1 (0.32) Jul 0.6 (0.42) 1.2 (0.51) 0.0 (0.32)

0.9 (0.46)

Nov 0.7 (0.44) 4.5 (0.81) Dec 10.4 (1.09)

0.1 (0.32) 22.9 (1.39)

Jan 1989 18.0 (1.30) 28.7 (1.48) 1.7 (0.56) 0.8 (0.45)

Feb 2.9 (0.69) 3.7 (0.76)

May 9.2 (1.05) 16.8 (1.27) 5.4 (0.87)

Aug 0.5 (0.40) 2.6 (0.66) 1.5 (0.54) Sep 1.3 (0.52) 5.6 (0.88) Oct 3.6 (0.75) 6.9 (0.94) 0.5 (0.40)

Mar 8.16 (1.00) 7.4 (0.97) 0.4 (0.39) 1.2 (0.51)

Mean b 6.38 (0.801) 13.51 (0.997) 4.67 (0.569) Increase (%) 34.9 189.3 -over LBL-T 40 W

a Figures in parentheses are transformed values. b Significantly different (p = 0.05) by DMRT.

Integrated pest management—weeds

Weed control in wet seeded rice in Kerala, India

P. P. Joy, E. K. Syriac, N. P. Nair, P. K. C. Nair, and C. A. Joseph, Rice Re- search Station, Moncompu, Thekkekara 688503, Kerala, India

The majority of farmers in the Kerala rice belt practice wet seeding. We evaluated nine weed control treatments to identify the most suitable method for wet seeded rice. The treatments involved four preemergence herbicides and hand weeding during monsoon (Jun-Oct) and wet season (Nov-Mar)

The field experiment was in a ran- 1988-89.

domized block design with three replications. The soil was silty clay. We sowed sprouted MO-6 seeds (115 d) on a puddled field at 100 kg/ha. Fertil- izers at 90-20-38 kg NPK/ha and herbicides were applied 6 d after seeding (DAS). Weeds were manually removed at fortnightly intervals to 45 DAS in the weed-free check (WFC),

and to 20 and 40 DAS in plots hand- Pooled analysis of data showed that weeded twice (HWT). interaction between season and treatment

Weed flora at 60 DAS consisted of was not statistically significant. All weed 22% grasses, 40% sedges, and 32% control treatments significantly reduced broadleaf weeds. Dominant weed species weed dry weight/m2 compared with the were Echinochloa colona, E. crus-galli, unweeded control (see table). lschaemum rugosum, Cyperus difformis, Grain yields with butachlor were high, C. iria, Fimbristylis miliacea, Ludwigia and on par with those of WFC and HWT. perennis, Marsilea quadrifolia, Its lower dose (1.0 kg ai/ha) was most Monochoria vaginalis, and Sphenoclea economic and is best suited to wet seeded zeylanica. rice in Kerala.

Effect of weed control treatments on wet seeded rice. Kerala, India, 1988-89. a

Weed Dose c

Benefit Cost of Marginal dry Grain Straw Gross of weed weed benefit-

Treatment b (kg ai/ha) weight yield yield return control control cost

(g/m 2 ) (t/ha) (t/ha) ($/ha) ($/ha) ($/ha) ratio

Tridiphane 48 EC 0.4 7.69 2.5 3.7 521 440 26 Tridiphane 48 EC 0.6

16.9 5.40 2.0 3.5 423 342 38

Butachlor (Thunder) 50 EC 1.0 4.36 2.0 3.4 415 334 15 9.0

Butachlor (Searle) 50 EC 1.0 5.75 2.7 3.5 559 478 15 22.3

Butachlor (Searle) 50 EC 1.5 4.61 2.6 3.0 545 464 22 31.8

Thiobencarb 10 G 1.5 8.91 2.4 2.6 501 420 35 21.1

Weed-free check (WFC) 12.0

4.16 2.8 3.6 589 508 101 Hand weeding twice (HWT) 4.50 2.5 2.8 514 433 70

5 .0

Unweeded check 6.2

LSD (0.05) 23.12 0.4 1.0 81 4.19 0.4 0.7

$28.67/liter, butachlor (Thunder) and (Searle) 50 EC (products of two companies) = $6,65/liter, thiobencarb 10 G = $2.20/kg, a Pooled mean of two seasons. b EC = emulsifiable concentrate. G = granule. c ai = active ingredient, Costs: tridiphane 48 EC =

grain = $200/t, straw = $5/t.


– – – – – – –

We studied nutrient composition of different golden snail meal forms and supplemental use in swine diets.

Meal forms were cooked and uncooked golden snail meal (GSM), golden snail meat meal, and golden snail shell meal. Feeds for growing/ finishing pigs were pure commercial feed mash (CFM), CFM + 5% GSM, CFM + 10% GSM, and CFM + 15% GSM.

Twelve growing male pigs (F 2 - Large White/Landrace) were individually fed for 110 d. Response criteria were statistically analyzed using completely randomized design.

Cooked and uncooked GSM had similar nutrient values (Table 1). GSM

had satisfactory crude protein (14.62- 17.15%), and minerals (ash), mainly Ca (28.55-30.87%).

Meat meal was more nutritionally balanced, with good gross energy and high crude protein. Ca and P were also

M. T. E. Catalma, D. T. Capil, R. A. Antalan, A. B. Serra, A. J. Barroga, and E. A. Orden, Animal Science De- partrnent, College of Agriculture, Central Luzon State University, 3120 Nueva Ecija, Philippines

Golden snail ( Pomaces sp.) use in animal feeds

Weed control economics in transplanted rice (TPR)

P. P. Joy, E. K. Syriac, N. P. Nair, P. K. C. Nair, and C. A. Joseph, Rice Research Station (RRS), Moncompu, Thekkekara 688503, Kerala, India

We evaluated the economics of prevail- ing weed control practices for TPR at RRS, Moncompu, during the 1988-89 monsoons (Jun-Oct) and wet season (Nov-Mar).

Three herbicides were tested against manual weeding in randomized block design with three replications. MO-7 rice (115 d) was transplanted at 15- × 15-cm spacing with 90-20-38 kg NPK/ha in a silty clay wetland. Herbicides were applied 6 d after transplanting (DT). Weeds were manually removed when they appeared in a weed-free check (WFC), and at 20 and 40 DT in plots hand-weeded twice (HWT).

Weed infestation was heavy. Domi- nant weed species were Echinochloa colona, E. crus-galli, Ischaemum rugosum, Cyperus iria, C. difformis, Fimbristylis miliacea, Limnophila indica, Monochoria vaginalis, Ludwigia perennis, and Marsilea quadrifolia.

three seasons. Pooled analysis showed statistically insignificant interaction between season and treatment. All

Results exhibited similar trends for the

herbicides were equally effective in weed control, were comparable to HWT, and superior to the unweeded check (see table).

Herbicide treatments resulted in grain yields on par with WFC, but significantly superior to HWT. Applying butachlor 50 EC at 1.0 kg ai/ha 6 DT was most economic for controlling weeds in TPR in Kerala.

Economics of weed control treatments in transplanted rice. Kerala, India, 1988-89. a

Treatment b Weed Grain Straw Gross Benefit Cost of Marginal

of weed weed benefit- (kg ai/ha) weight

(g/m 2 ) (t/ha) (t/ha) ($/ha) control control cost

($/ha) ($/ha) ratio

Dose c dry yield yield return

Anilophos 30 EC 0.6 29.35 2.3 3.4 483 430 23 18.7 2,4-D EE 4 G 0.8 24.45 2.4 3.6 496 443 23 19.3 Butachlor 50 EC 1.0 32.10 2.3 3.5 474 421 15 28.1 Weed-free check (WFC) 4.63 2.4 3.9 496 443 98 4.5 Hand weeding twice (HWT) 33.78 2.0 3.2 412 359 69 5.2 Unweeded check 73.55 0.3 0.2 53

LSD (0.05) 18.91 0.7 1.4 a Pooled mean of 3 seasons. b EC = emulsifiable concentrate. G = granule. c ai = active ingredient. Costs: anilophos = $8.67/liter, 2.4- D EE = $0.87/kg, butachlor = $6.65/liter, rice gram = S200/t. straw = $5/t.

Integrated pest management—other pests

Table 1. Composition of different feedstuffs derived from golden snail on a dry matter basis.

Golden snail Golden snail Golden snail meal Golden snail meal

(cooked) (uncooked) meat meal shell meal

Dry matter (%) 90.30 89.90 86.10 98.60 Gross energy (kcal/kg) 605.61 671.45 3336.27 Crude protein (%) 14.62 17.15 62.48 4.30 Ether extract (%) 0.88 0.56 3.48 0.50 Crude fiber (%) 3.43 3.45 4.65 3.00 Nitrogen-free extract (%) - 0.44 13.36 0.90 Calcium (%) 30.87 28.55 3.40 35.05 Phosphorus (%) 0.30 0.26 1.22 0.01

Table 2. Average production performance of growing finishing pigs fed a diet supplemented with different levels of GSM. a

CFM CFM + 5% GSM CFM + 10% GSM CFM + 15% GSM

Initial wt (kg) 24.00 24.33 Final wt (kg) 85.50 88.16 Total wt gain (kg) 61.00 63.83 Daily wt gain (kg) 0.55 0.58 Total feed consumption (kg) 264.00 265.10 Daily feed consumption (kg) 2.40 2.41 Feed conversion efficiency 4.33 4.15 a Statistical analysis showed insignificant differences among the treatments.

23.66 83.50 59.34 0.54

264.00 2.40 4.45

25.00 91.67 66.67

0.61 259.60

2.36 3.89


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high with a 3:1 ratio. Golden snail meat Table 2 shows average production showed insignificant differences across meal can safely replace fish or meat meal performance of growing/finishing pigs treatments. in food animal diets. fed GSM-supplemented diets. The The results indicate GSM could be

Ca. It could potentially replace oyster average daily feed consumption, and finishing pigs. shell meal. average feed conversion efficiency—

Shell meal was Ca-rich, with 35.05% response criteria—average daily gain, used as a feed supplement for growing/

Loss of rice grain yield and seedling vigor due to sheath rot (ShR) and mealy bug interaction

P. Lakshmanan, Plant Pathology Department; S. M. Kumar and R. Velusamy, Entomology Department; and K. Indira, Seed Technology Department, Agricultural College and Research Institute (ACRI), Killikulam, Vallanad 627252, Tamil Nadu, India

We observed a severe ShR Sarocladium oryzae (Sawada) W. Gams and Hawksw. outbreak in Sep-Oct 1990 in IR20

used. About 100 samples, replicated five times, represented each severity class.

Mealy bugs inside ShR-infected sheaths were counted for each class. Panicles within seventy classes were bulked, dried separately. Thousand- grain weight and percent of healthy, discolored, and chaffy grains were recorded.

We evaluated seedling vigor after storage for 1 mo at room temperature with a standard test. Fifty seeds were incubated between double-layer blotter paper in 9-cm plates for 2 wk at 25ºC with four replications per sample. We recorded the number of germinated seeds,

ricefields infected with mealy bug and shoot and root lengths after 2 wk. Brevennia rehi Lindinger. ShR severity was positively correlated Correlation of sheath rot severity and mealy bug

assessed and tagged with waterproof (see figure). Their interaction greatly color tape according to ShR severity at reduced 1,000-grain weight, grain yield Seed germination and root length were grain maturity stage. The Standard (9-77%), and healthy grains percentage; significantly reduced, but shoot length evaluation system for rice (SES) was it increased chaffy and discolored grains. was not.

The flag leaf of individual tillers was (r = 0.99**) with mealy bug population population Sep-Oct 1990 at ACRI.

Water management We measured use of water by summer

Water use by irrigated rice through evapotranspiration and deep summer rice percolation. Soils were medium black,

clay loam texture, pH 6.9, 0.82% organic V. N. Khade, B. P. Patil, L. S. Chavan, C, infiltration rate 1.0-1.5 cm/h. and S. A. Khanvilkar, Konkan Agricul- The technique used two 200-liter tural University, Dapoli 415712, Mahar- capacity leakproof drums, 60 cm in ashtra, India diameter and 90 cm high. One drum had

an open bottom; the second, a closed bottom. The drums were installed in oversized pits 60 cm deep and 65 cm in diameter in the ricefield, leaving about 30 cm of the drum height aboveground. The soil was backfilled layerwise and com- pacted to approximately the same bulk density as that of the surrounding soil.

Mean evapotranspiration use and deep percolation loss at different growth phases of summer rice. a Maharashtra, India, 1987-89.

Water use (mm)

Open-bottom drum Closed-bottom drum

Transplanting Maximum Flowering Milk Total Transplanting Maximum Flowering Milk Total to maximum tillering to to milk to (90 d) to maximum tillering to to milk to (90 d)

Total evapotranspiration 528.3 678.9 342.0 450.4 1999.6 280.8 372.9 203.9 271.0 1128.5 + deep percolation

Average/d 21.1 22.6 22.8 22.5 11.2 12.4 13.6 13.6 Through evapotranspiration Through deep percolation 247.5 306.0 138.2 179.4 Deep percolation/d 9.9 10.2 9.2 8.9

871.1

Percolation (%) 46.9 45.1 40.4 39.8 a Av for 3 yr.

tillering flowering stage maturity tillering flowering stage maturity

280.8 372.9 203.9 271.0 1128.5


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-

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A. S. R. A. S. Sastri and J. L. Chaudhary, Indira Gandhi Agricultural University, Raipur 492012, Madhya Pradesh, India

At transplanting, the surface soil in each drum was brought to the same puddled condition as that of the surrounding field.

Seedlings of rice variety Ratna were percolation occurred from tillering to transplanted in mid-Jan. A 5-cm water flowering (see table). Of a total 1999.5 level was maintained by refilling with a mm water used by the crop, 56.4% met

Water use in the open-bottom drum measured quantity of water. There was evapotranspiration needs; 43.5% was lost constituted evapotranspiration and deep no rainfall during the growing season, through deep percolation. percolation; water use in the closed-bottom The highest water use through drum constituted evapotranspiration alone. evapotranspiration (732.9 mm) and deep

Water balance in bunded Water balance of different districts.

ricefields under different rainfed situations in Central

Sandy loam (Matasi) Clay loam (Dorsa) Clay soils (Kanhar) Parameter

India (mm) Excessive Normal Deficit Excessive Normal Deficit Excessive Normal Deficit

Rainfall 1813.5 1142.2 763.2 1813.5 1142.2 763.2 1813.2 1142.2 763.2 Percolation 1032.6 434.9 137.1 730.8 389.6 76.1 220.2 312.6 26.3 Runoff

Raipur

85.1 0 0 262.9 0 0 398.3 27.2 0

The Chhattisgarh region of Central India grows about 5 million ha of rice, 20% irrigated, the rest rainfed. Soil variability ranges from lateritic to clay to sandy loam and clay loam.

We examined the climatic water balance under bunded field condition in three major riceland soils. We computed excessive, normal, and deficit rainfall situations for four stations using the Thornthwaite and Mather (1955) book- keeping procedure.

tion values were used to obtain soil moisture storage, actual evapotranspiration, water deficit, and water surplus. We assumed that runoff occurred only with more than 10 cm standing water in bunded ricefields, and percolation losses are always higher than runoff losses.

under water surplus conditions in the water balance computations. The amount of water at field capacity was assumed to be 150 mm for sandy loam, 200 mm for clay loam, and 250 mm for clay soils, up to 1 -m depth.

For annual rainfall data, three rainfall patterns were worked out for 1901-1987: excessive (greater than mean [MI + standard deviation [SD]), normal ( M + SD to M - SD), and deficit (less than M - SD).

The probability of excessive rainfall pattern occurrence at the four stations ranged from 8 to 17%; that of normal

Rainfall and potential evapotranspira-

The two water losses were estimated


Rainfall Percolation Runoff



2002.3 958.0

75.2

1736.5 981.2

0

1475.6 970.9 18.5

1232.2 535.8

0

1136.7 450.5

0

1201.0 462.1

0

682.4 2002.3 1232.2 Rajnandgaon

59.2 850.7 475.8 0 323.1 10.0

Durg 862.7 1736.7 1136.7 244.8 390.5 390.5

0 0 0

Bilaspur 804.3 1475.6 1201.0 153.2 499.4 390.1

0 143.8 22.0

682.4 8.3 0

862.7 193.8

0

804.3 103.2

0

2002.3 621.6 724.1

1736.9 580.5 375.7

1475.6 399.4 244.4

1232.2 682.4 405.7 0

29.7 0

1136.7 862.7 314.8 137.6

24.8 6.2

I201.0 804.3 348.3 52.7

13.9 0

Annual rainfall pattern at Mahasamund, 1907-87.

rainfall, from 61 to 77%; and that of deficit rainfall, from 10 to 22%.

The potential evapotranspiration required for water balance computation was worked out using Penman’s (1948) equation. The normal value was consid- ered for all three rainfall categories because the time series data required for calculation were unavailable. Moreover, all four stations were in the same agroclimatic region.

At all the stations and in all rainfall distribution categories, runoff losses were negligible compared with percolation losses in all soil types, except for clay soils under excessive rainfall (see table).

With deficit rainfall, even percolation losses were very low, with higher values in lighter soils. With normal rainfall, percolation losses accounted for 35-45% of light soil losses.

With decreasing rainfall (see figure)

and a major area under light soils, the cropping pattern must be diversified. But because most fields are bunded and the region is a plains area, rice cultivation seems inevitable. Limited supplemental irrigation is important for rainfed rice in this area. Groundwater use through “dug” and “dug cum bore” wells may be suited to this region because of high percolation losses.

ANNOUNCEMENT New IRRI publications

Program report for 1990

A farmers primer on growing upland rice (in Cebuano)


ISS

N 0117-0880

AN

NU

AL R

EP

OR

TS

IRR

I Program R

eport for 1990 International R

ice Research Institute

1991. 317 pages. 17.78 × 25.40cm. H

DC

US

$38.30, LDC

US

$11.50 plus airm

ail (US

$7.00) or surface mail (U

S$2.00) postage.

The ecosytem

-structured P

rogram R

eport for 1990—

the definitive

record of

IRR

I w

ork that year — provides the

baseline for assessing future progress in rice research and related activities. It covers w

ork that will help m

eet the need for a stable food supply, for people living now

and for the 3-4 billion m

ore people who w

ill depend on rice in 2020. S

ome of the projects are far up the scale of strategic w

ork, som

e are closer to applied work that national agricultural

development

programs

can adapt

to their

particular situations.

IRR

I IN

TERN

ATIO

NA

L RIC

E RESEA

RC

H IN

STITUTE

WE

ED

S

ISB

N

971-22-0020-5

A H

andbook for W

eed Control in R

ice K

. Am

pong-Nyarko and S

.K. de D

atta

1991. 113 pages. 21.59 × 27.94 cm P

aperback. HD

C U

S$12.50, LD

C

US

$3.25 plus airmail (U

S$5.00) or surface m

ail (US

$2.00) postage.

Farmers everyw

here search for ways to w

iden the narrow

margin of profit betw

een production costs and crop returns. W

eeds cause more yield losses in ricefields than any other

pest. Cost-effective m

ethods for controlling weeds could

help preserve profits and increase yields.

weeds in the m

any different rice cultural systems, using an

integrated managem

ent approach. It can be used as a textbook, as a field guide, or as a m

anual for making

decisions in crop managem

ent. The handbook w

as designed to facilitate its translation and copublication. Those w

ho are interested in publishing it

in languages

other than

English

should contact

Com

munication and P

ublications Services, IR

RI Inform

ation

This book provides practical information on controlling

Center.

INTER

NA

TION

AL R

ICE R

ESEAR

CH

INSTITU

TE IR

RI

Documents

International Rice Research Newsletter Vol.16 No.6