international rice research newsletter vol.11 no.1

Contents

GEU EVALUATION AND UTILIZATION Overall progress

3 White ponni rice in Tamil Nadu 3 NLR9672 and NLR9674 released for cultivation in southern Andhra

4 New rice varieties derived from BG90-2 5 HKR120, a promising new rice

Pradesh

Disease resistance 5 Disease-resistant IRRI varieties in Tamil Nadu 6 Sheath blight (ShB) damage to seven rices 6 Reaction of IRRI and Tamil Nadu rices to yellowing syndrome 6 Screening for resistance to bacterial blight (BB) 7 Reactions of IRRI rices to rice diseases in Tamil Nadu

Insect resistance 7 Resistance of Nephotettix virescens gene sources to Asian N. virescens

8 Field evaluation of rices for whitebacked planthopper (WBPH) and populations

leaffolder (LF) resistance

18 A new rice disease in Manipur, India 18

19

19

20 20 21 21 22 23 23

Reaction of green leafhopper (GLH)-resistant varieties to rice tungro virus (RTV) complex Rice gall dwarf virus (GDV) outbreak in West Guangdong Province, China Breakdown of Xa 4 gene for resistance to bacterial blight (BB) at Pantnagar, India Effect of bulky organic manures on sheath blight (ShB) Maize — a new host of rice gall dwarf virus (GDV) Rice diseases on the Godavari Delta BR3 reaction to multiple disease infection Sheath blight (ShB) control Influence of sheath blight (ShB) on agronomic traits at different N levels Effect of inoculum age on transmission of rice gall dwarf virus (GDV)

Other pests 23 Estimating rat damage in deep water rice 24 Traditional pest control practices in West Africa 25 Burrowing pattern of bandicoot rats in deep water rice fields 25 Bandicoot rat damage in deep water rice fields

9 Varietal screening for leafhopper and planthopper resistance at Varanasi, India SOIL AND CROP MANAGEMENT

Agronomic characteristics 26 Sources and methods of N application for drilled, rainfed lowland rice 10 Performance of IR64 at Tamil Nadu Rice Research Institute (TNRRI) 26 Effect of nursery bed nutrient management and seed treatment on rice

Deep water grain yield

conditions 10 Elongation ability of deep water rice at two nitrogen levels 26 Yield response of IR36 and IR42 to N application under nonsubmerged

PEST CONTROL AND MANAGEMENT Insects

11 Whitebacked planthopper (WBPH) outbreak in Haryana, India 11 Need-based control of yellow stem borer (YSB) 12 Virulence of whitebacked planthopper (WBPH) populations in South and

Southeast Asia: report of a collaborative project 13 A carbon dioxide-cone (CO 2 NE) sampler for arthropods in flooded rice 14 Brown shield bug attack on rice 14 Rice hispa in Burdwan, West Bengal 15 Virulence of green leafhopper (GLH) colonies from Luzon, Philippines,

15 Influence of planting time and rainfall on gall midge (GM) incidence and

16 Oviposition of rice whorl maggot (RWM) in wet seedbeds

on IR36 and IR42

rice yield in Goa, India

Diseases 17 Spread of rice tungro spherical virus (RTSV) in Bicol, Philippines

27 Ratoon crop performance of three rices 27 Regulating K + and Na + in two rice varieties grown in sodic soils 28 Nitrogen use efficiency in relation to seedling age and transplanting time 28 Herbicides reduce azolla growth 29 Effect of soil amendments on summer growth and survival of Azolla

29 Some physiological studies on rice grown on manganese-deficient soil 30 The Na-K ratio as index of salt stress in rice cultures 30 Azolla as a substitute for N fertilizer in rice cultivation 31 Effect of phosphorus on kharif rice 31 Storing Azolla pinnata inoculum for transport

pinnata

ANNOUNCEMENTS 32 Chang honored 32 Yuan Longping receives World Intellectual Property Organization

(WIPO) gold medal 32 New IRRI publications

Guidelines and Style for

IRRN Contributors

Articles for publication in the International Rice Research Newsletter (IRRN) should observe the following guidelines and style.

Guidelines • Contributions should not exceed two pages of

double-spaced typewritten text. Two figures (graphs, tables, or photos) may accompany each article. The editor will return articles that exceed space limitations.

• Contributions should be based on results of research on rice or on cropping patterns involving rice.

• Appropriate statistical analyses should be done.

• Announcements of the release of new rice varieties are encouraged.

• Pest survey data should be quantified. Give infection percentage, degree of severity, etc.

Style • For measurements, use the International

System. Avoid national units of measure (cavan, rai, etc.).

measure when they follow a number. For example: 20 kg/ha, 2 h/d.

• Abbreviate names of standard units of

• Express yield data in tonnes per hectare (t/ ha). • With small-scale studies, use grams per pot

(g/pot) or g/row. • Express time, money, and common measures

in number, even when the amount is less than 10. For example: 8 min, $2, 3 kg/ha, 2-wk intervals.

• Write out numbers below 10 except in a series containing 10 or higher numbers. For example: six parts, seven tractors, four varieties. But There were 4 plots in India, 8 in Thailand, and 12 in Indonesia.

• Write out numbers that start sentences. For example: Sixty insects were put in each cage. Seventy-five percent of the yield increase is attributed to fertilizer.

• Place the name or denotation of chemicals or other measured materials near the unit of measure. For example: 60 kg N/ha, not 60 kg/ ha N; 200 kg seed/ ha, not 200 kg/ ha seed.

• Use common names — not trade names — for chemicals.

• The US$ is the standard monetary unit in the IRRN. Data in other currencies should be converted to US$.

• When using acronyms, spell each out at first mention and put the specific acronym in parentheses. After that, use the acronym throughout the paper. For example: The brown planthopper (BPH) is a well-known insect pest of rice. Three BPH biotypes have been observed in Asia.

• Abbreviate names of months to three letters: Jun, Apr, Sep.

• Define in the footnote or legend any nonstandard abbreviations or symbols used in a table or figure.

bibliography. • Do not cite references or include a

Genetic Evaluation and Utilization OVERALL PROGRESS

White Ponni rice in Tamil Nadu

P. Vivekanandan, J. Venkatakrishnan, K. Nilakantapillai, R. Swaminathan, and D. S. Aaron, Paddy Experiment Station (PES), Tirur 602025, Tamil Nadu Agricultural University, Tamil Nadu, India

White Ponni was introduced in India from Malaysia. It is a tall indica from Taichung 65 Mayung Ebos 80 and matures in 135 d. It has medium-slender white grains with good cooking quality.

transplanting and direct seeding in Tamil Nadu. We compared it and other popular varieties at PES in samba (Jul- Aug to Nov-Dec) and late samba (Sep-

White Ponni is popular for

Oct to Jan-Feb). For direct-seeding trials, seeds were

sown when rains began and the fields later were flooded (see table). The crop received 10 t of farmyard manure/ha and 50 kg N/ha was topdressed in equal splits 30 and 45 d after seeding. Transplanted trials with tall indicas received a basal 15-14 kg PK/ha, and 52 kg N ha was topdressed in equal splits 20 and 40 d after transplanting. Semidwarfs received a basal dose of 22- 42 kg PK/ha and 100 kg N/ha was applied in 4 equal splits at 10-d intervals after transplanting.

White Ponni yielded highest under all conditions (see table).

Performance of White Ponni under transplanted and direct-seeded conditions, Tamil Nadu, India.

Samba 1984-85 a Late Samba 1984-85 b

Variety Parentage Days to Yield Days to Yield flowering (t/ha) flowering (t/ha)

White Ponni

PY 1 Ponni Co 43 IR20

Paiyur 1

White Ponni Bam3 Co 31 IR20

TG65/ME80

Ponni/IR8 TC65/ME80 Dasal/IR20 IR262ITKM6

IR1721-14/IR1330-3-3-2

TG65/ME80 Bayyahunda-Pureline GEB24/O. perennis IR262/TKM6

100 105 100

93 98

–

93 99 98

Transplanted 3.1 100 4.0 3.0 103 3.3 2.5 103 3.3 – 105 3.9

2.4 100 3.0 2.4 98 3.8

Direct-seeded c

2.2 1.2 1.5 0.2

a Sown 14 Aug, planted 8 Sep 1984, b Sown 17 Oct, planted 23 Nov 1984. c Sown 21 Sep 1984.

NLR9672 and NLR9674 released for cultivation in southern Andhra Pradesh

G. V. Reddy, D. V. S. R. Rao, K. J. Reddy K. S. Narayana, and G. V. Rao, Agricultural Research Station (A RS), Nellore 524004, India

NLR9672 and NLR9674, developed at ARS, are high yielding semidwarf rices that were released as Kotha Molagolukulu for cultivation in wet

season in Nellore, Prakasam, and parts of Cuddapah and Chittoor. Both are from the cross of Bulk H/9 and Milekkunning. Bulk H/9 is a selection from local Pedda Molagolukulu and has good grain quality. Milekkunning is a Malaysian variety with blast (Bl) resistance.

NLR9672 matures in 160-170 d and NLR9674 in 170-180 d. They are weakly photoperiod-sensitive. NLR9674 has a droopy flag leaf, and NLR9672 has an erect flag leaf. They have good tillering

IRRN 11:1 (February 1986) 3

116

ability and produce many grains per panicle (Table I). Both varieties have grain type similar to that of Molagolukulu, which is locally preferred. Grains are short and bold with white, translucent kernels and have excellent cooking and keeping qualities. Seed dormancy also is desirable. Both the varieties perform well, even if 60-d- old seedlings are planted late in wet season. NLR9672 is moderately resistant to B1 and bacterial blight, and NLR9674 is B1 resistant.

In five yield trials from 1970 to 1974 (Aug-Sep to Jan), NLR9672 followed by NLR9674 yielded significantly higher than Bulk H/9. In 1975 minikit trials at 20 sites in Nellore. NLR9672 yielded an average 17% and NLR9674 10% higher than Bulk H/9 (Table 2).

NLR9674 is on 200,000 ha in Nellore NLR9672 is grown on 250,000 ha and

Table 1. Agronomic traits of NLR9672 and NLR9674 at Nellore, India.

Variety Duration (d)

Plant Panicles/m 2 Grains/ 1,000-grain ht panicle wt (g)

(cm)

NLR9672 160 100 248 339 23.5 NLR9674 170 104 269 326 BulkH/9

22.5 180 150 198 192 22.0

Table 2. Grain yields of NLR9672 and NLR9674 at Nellore, India.

Grain yield (t/ha)

Variety 1970 1971 1972 1973 1974 Mean 1975 minikit trial a

NLR9672 5.4 5.7 6.1 3.8 4.4 5.1 4.0 NLR9674 5.2 5.7 5.9 3.5 4.1 4.9 3.7 BulkH/9 3.8 5.4 5.3 3.1 3.3 4.2 3.3

CD P = 0.05 0.5 0.2 0.5 0.3 0.5

a Mean of 20 locations.

and Prakasam and parts of Guntur, Cuddapah, and Chittoor.

New varieties derived from BG96-2

C.S. Ying, China National Rice Research Institute, Hangzhou; H. Jiang, Jiangsu Provincial Academy of Agricultural Sciences; and D. B. Fei, Jiangpu County Institute Agricultural Sciences, Nanjing, China

BG90-2 was developed in Sri Lanka. Introduced in China in 1976, it was released in Nanjing as a midseason variety in 1979 because it has excellent

morphoagronomic characters and high resistance to bacterial blight (RH). Its growth duration exceeds 150 d. however, which makes it difficult to grow after wheat. Several promising varieties or lines have been developed from BG90-2.

B-xuan 1 and B-fu 1 were selected from BG90-2 by the Jiangpu County Institute of Agricultural Sciences in 1979; 910 and Yang-dao 1 were developed by the Yangzhou District Institute of Agricultural Sciences,

Yangzhou. Jungsu Province, in 1980. B-xuan 1, 910. and Yang-dao 1 were derived from BG90-2 as pureline selections, but B-fu 1 was developed by irradiating BG90-2 seeds with Co 60

gamma rays. The new varieties and lines have shorter growth duration than BG90-2 and good characters (see table). They have been widely planted in Honan, Hubei, Anhui, and Jiangsu Provinces. By 1984 they had covered 400,000ha.

Characteristics of varieties derived from BG90-2, Nanjing, China.

Variety Seeding Growth Panicle Grains/ Fertile 1,000- Grain Reaction a

Height to full duration length panicle grains/ (cm) heading panicle (%)

Sterility seed yield to

(d) (d) (m) (no.) wt (g) (t/ha) BB (no.)

B-xuan 1 107 102 136 28 131 102 22 30 8.8 R

Yang-dao 1 91 97 129 24 132 116 13 25 7.7 S R

BG90-2 (parent) 113 115 154 26 161 128 20 27 8.2 R

a R = resistant, S = susceptible.

910 100 103 137 28 136 100 27 29 8.6 R

B-fu 1 106 95 126 26 111 98 12 36 7.6

The International Rice Research Newsletter (IRRN) invites all scientists to contribute concise summaries of significant rice research for publication. Contributions should be limited to one or two pages and no more than two short tables, figures, or photographs. Contributions are subject to editing and abridgment to meet space limitations. Authors will be identified by name, title, and research organization.

4 IRRN 11 :1 (February 1986)


the Standard evaluation system for rice 0-9 scale (see table).

Only RTV was present in kuruvai. In thaladi, RTV, B1, sheath rot (ShR),

brown spot (BS), bacterial leaf blight (BLB), and grain discoloration (G1D) were common. Evaluation of these selections will continue in 1985.

Between 1982 and 1984, blast (B1) and tungro virus (RTV) caused serious yield losses in Tamil Nadu. Commonly grown TKM9 and IR50 were susceptible to B1 and ADT31, ADT36, TKM9, and IR20, to RTV. We evaluated 37 IRRI rices for disease resistance at TNRRl in 1984-85 kuruvai (Jun planted) and thaladi (Sep planted).

For RTV screening in the glasshouse, 1 viruliferous green leafhopper that had fed for 4 d on RTV-infected plants was placed on each 10-d-old seedling for 2 d. For Bl screening in the greenhouse, 15- d-old seedlings were spray-inoculated with a conidial suspension (20,000 cells/ml) of the Bl fungus and kept in polythene tents in high humidity for 24 h before and after spraying. The varieties were also field-screened under natural conditions with 100 kg applied N/ha. Disease incidence was scored by

V. Mariappan and S. Chelliah, Tamil Nadu Rice Research Institute (TNRRI), Aduthurai 612101, Tamil Nadu, India; and G. S. Khush IRRI

Disease-resistant IRRI varieties in Tamil Nadu

Performance of HKR120 in Haryana, India.

Av yield Duration Panicles/ Milling Length: Kernel BB a WBPH b

Variety (t/ha) (d) m 2 (%) Width

elongation quality Cooking

(0-9 (0-5 Rating c 1982-84 (mm) scale) scale)

HKRl20 PR106 Jaya

CD at 5% CV %

6.5 6.1 6.0

0.5 5.4

146 148 147

0.7 7.5

296 313 298

0.3 3.9

67 67 71

3.43 3.25 2.86

1.98 1.98 1.76

Good Good Fair

3 7 7

0.7 3 4.0 4.5

R S S

a Based on the Standard evaluation system for rice. b Based on Kalode et a1 1975. c R = resistant, S = susceptible.

58.5

HKR120, a promising new rice

R. Pal, A. Singh, and D. V. S. Panwar, Haryana Agricultural University, Rice Research Station (HAURRS), Kaul 132021, Kurukshetra, India

HKR120 is a promising, medium- duration (140-145 d) semidwarf

developed from Ptb 33/4*IR3403-267-1 stability (see table) because it is resistant at IRRI. Tested in the 1981 to bacterial blight (BB) and whitebacked International Rice Observational planthopper (WBPH), which are major Nursery, it showed good phenotypic pests in Haryana. Its grains are long, acceptability. Under evaluation at slender, translucent, and have no white HAURRS in 1982-84, it yielded more belly. Quality is as good as that of and had better tillering capacity than the PR106. checks PR106 and Jaya. It has yield

Genetic Evaluation and Utilization DISEASE RESISTANCE

Disease resistance of IRRI varieties in Tamil Nadu, India. Disease infection

Variety

(0-9) (%)

RTV(%) Leaf Bl Neck Bl ShR BS BLB G1D

Glasshouse Field Greenhouse Field (%) (%) (0-9) (0-9) (%)

IR9179-209-2-2-2-3 8 0 0 0 1 3 0 0 IR13423-10-2-3 0 0 0 0 0 3 3 1 Stray IR13429-299-2-1-3-1 (IR60) 4 0 0 0 0 3 3 1 0 IR1 7494-32-1-1-3-2

IR24632-34-2

16 8 0 0 0 1 3 1 5 IR18349-53-1-3-1-3 0 0 0 0 0 1 1 1 5

14 0 0 0 0 5 3 3 10 IR31802-48-2-2-2 8 0 0 0 0 3 3 1 10 IR32307-10-2-1-1

IR32429-47-3-2 IR32429-68-3-3-3

IR32385-37-3-3-3 10 0 0 0 0 1 3 3 0 24 0 0 0 0 3 3 1 0 19 0 0 0 0 3 3 1 0 7 0 0 0 0 3 3 0 0

IRl3423-17-1-2-1 0 0 5 4 0 1 1 1 5

IR31851-63-1-2-3-2 0 0 7 60 0 0 3 1 2 IR31868-64-2-3-3-3 0 0 5 3 0 3 3 0 9

IR54 18 5.9 0 0 0 3 3 1 5 IR58 0 0 0 0 0 3 3 Stray 0

IR13927-40-2-3-3-3-3 0 0 3 1 0 3 3 1 0 IR28143-66-3-3-2 0 0 5 37 0 1 3 1 5

IR29725-3-1-3-2 0 0 3 5 1 3 3 3 0

IR50 0 0 7 50 40 5 5 3 5 Co33 62 57.6 7 62 58 7 5 9 10 TKM9 65 60.0 7 53 45 5 5 3 5 ADT36 70 3 6 0 5 3 5 5 IR20 48 45.0 3 4 0 3 3 3 2

0

Sheath blight (ShB) damage to seven rices

C.P. D. Rajan, assistant plant pathologist, Agricultural Research Station, Maruteru; and V. D. Naidu, assistant plant pathologist, Agricultural Research Station. Nellore, Andhra Pradesh, India

ShB caused by Rhizoctonia solani Kuhn [ Thanetophorus cucumeris (Frank) Donk.] causes major yield losses on the Godavari Delta in Andhra Pradesh.

We evaluated seven rices (see table) for ShB resistance in 1982-83 rabi. Rice was planted at 15- × 15-cm spacing in 3.00- × 4.05-m plots in a split-plot design with 3 replications. All treatments received 120-30-30 kg NPK/ ha. Plants in the disease treatment were inoculated at panicle initiation with ShB-infected leaf bits.

Reaction of IRRI and Tamil Nadu rices to yellowing syndrome

M. Subramanian, A. P.M. K. Sundararaj, and V. Sivasubramanian. Tamil ,Nadu Rice Research Institute (TNRRI), Aduthurai 612101, India

Scattered leaf yellowing was noticed in rice in the Tamil Nadu delta zone in 1984 kuruvai (Jun-Jul to Sep-Oct). All local varieties, including ADT31, ADT36, and TKM9, were affected, but recovered greenness within 10 d when sprayed with 3% diammonium phosphate. Yield did not seem to be affected. Leaf yellowing was more severe in thaladi (Sep–Oct to Jan–Feb) and samba (Jul–Aug to Jan–Feb). IR20 yielded nothing. Ponni, White Ponni, and Paiyur 1 survived but yielded low.

Leaf yellowing seems to be caused by a complex set of factors and therefore is called yellowing syndrome.

We evaluated 18 medium- and 2 short-duration IRRI varieties and 14 long- and 7 medium-duration Tamil Nadu varieties for field reaction to yellowing syndrome in Sep–Oct 1984. Leaf yellowing incidence was 100% in susceptible lines and check variety IR20. Varieties were scored as follows: 0 = highly resistant, 1 = resistant, 3 =

6 IRRN 11:1 (February 1986)

Yield losses caused by ShB in 1982–83 rabi in Maruteru, India.

Percentage Filled grains (%) Variety disease

index Healthy Diseased

BPT1235 65 92 80 IET1444 46 92 87 IR50 61 92 71 IR36 72 86 71 RP4-14 52 84 75 MTU6182 43 89 76 RGL 2624 72 91 74

Mean 49 89 76 CD V 15 2.8 (P: 0.05%) H × D 1.7 CV % 14.2 3.3

Grain yield (t/ha)

Healthy Diseased

5.1 6.0 6.9 7.8 6.0 5.7 6.0 6.2

4.2 5.4 4.2 5.3 5.1 4.5 4.2 4.7

4.4 11.9

Yield loss (%)

18 10 39 33 15 21 30 24

RGL 2624 had highest percentage PDI was correlated positively with disease index (PDI) (see table). ShB yield loss ( r = 0.5606) and negatively caused significant yield losses in all with percentage of filled grains ( r = varieties. Yield loss was highest in IR50, –0.5236), which was negatively correlated followed by IR36 and RGL 2624. Yield with percentage yield loss ( r = loss was primarily due to a significant –0.5148). reduction in filled grains.

moderately resistant, 5 = moderately susceptible, 7 = susceptible, and 9 = highly susceptible (100% yellowing, drying, and severe stunting).

Medium-duration IR32, IR34, IK42, IR54, and IR56 and short-duration IR36 and IR50 were resistant (score 1– 3). Medium-duration IR25, 1K38, IK44. and IR45, and short-duration IR36 and lR50 were moderately susceptible (score 5). Medium-duration IR5, IR8, IR20, IR24, IR26, IR40, IR43, IR46, and IR48 were highly susceptible.

Long-duration ADT1, ADT2, ADT5,

ADT10, and ADT13 and medium- duration White Ponni were highly resistant (score 1). Long-duration ADT22, ADT25, and CR1009 (Ponmani or Savithiri), and medium- duration Paiyur 1 and Pondicherry 1 scored 3. Long-duration ADT6, ADT8, and ADT24. and medium-duration ADT35 and Co 43 were moderately susceptible. Long-duration ADT7, ADT11. and ADT21 and medium- duration Co 36 were highly susceptible (7–9). Unreleased medium-duration AD9408 scored 3–5.

Screening for resistance to bacterial soaking small pieces of natural1y blight (BB) infected leaves in water for 20 min. The

Standard evaluation system for rice was used to score reaction. D. Singh, A. Singh, and S. Sunder, Rice

Research Station (R RS), Kaul, Kurukshetra Entries with a resistance score of 1 132021, India were BAM-10, BG90-2, W1263, 1R2055-

BB caused by Xanthomonas campestris CR129-18, RP2151-173-1, RP2151-40-1, pv. oryzae is a major rice disease in RP2151-4-21-1, RP2151-33-4, RP2151- Haryana. We evaluated 280 lines for BB 33-2, RP2151-21-1, CR319-644, resistance at Haryana Agricultural RP1575-143-823-1, RP2151-173-1-8, University RRS in 1983–84 kharif. RP2151-224-4, RP2151-200, RP2151-

Each line was planted in two 5-m- 40-1, IET4141, UPR82-1-7, M.S.S.,

long rows in 2 replications. Plants were Wase Aikoku 3, Kogyoku, and DV85.

inoculated 45 d after transplanting by Entries with a resistance score of 3 cutting 5 cm of the upper leaves with a were Lastroval, Sigadis, T-201902, sickle dipped in inoculum prepared by IET4135, AC1613, B459-PN-4-5-6-1,

481-24-2, RP632-94-1-2-1-7, RP633-C,

BKN681-9-33-3-21-3, KNth 361-1-8-6, IR1550-8, IR2053-362-1-4-4, BJ-1, FH663, CR44-1018, CR75-93, BR51-245-1, BR51-331-4, BR52-90-2, IR2053-375-1-1-5, IR2060-213-2-17, CR167-10, CR164-12, CR316-639, Pusa 2-33, Tea-1-P 2 -5-2, B-4-90-2, IR2061-464-2-4-4-6, IR2061-522-6-9, HAU5-9-1, HAU5-101-1, RP5-32, RP- IR577-24-1-1-5, IR578-111-2-2, IR2070-414-39, IR2070-423-2-5-6, 291-74, UPR173-23, UPR82-1-7, and IR41154-357-2-3-2, IR1544-238-2-3, IR2071-527-3-1-5, IR50, IR52, PR107, UPR173-1-8.

Reactions of IRRI rices to rice diseases in Tamil Nadu

M. Subramanian, A. P.M. K. Sundararaj, and V. Sivasubramanian, Tamil Nadu Rice Research Institute (TNRRI), Aduthurai, Tamil Nadu 612101, India

In 1984 thaladi (Sep-Oct to Jan-Feb), rice in Tamil Nadu was damaged by yellowing syndrome (YS), which often caused total crop loss, and by bacterial blight (BB), Helminthosporium (H), sheath blight (ShB), and grain discoloration (GID). The 1984 International Rice Yield Nursery was grown under this disease pressure, and rices were evaluated using the Standard evaluation system for rice (see table).

Of 30 entries in the trial, 10 had multiple disease resistance: BR40-300- 1-2, IR18349-22-1-2-1-1, IR19672-140-2- 3-2-2, IR21820-154-3-2-2-3, IR21848-65- 3-2-2, IR25587-133-3-2-2-2, IR25603-20- 2-1-3-2, IR27325-63-2-2, IR28118-138- 2-3, and IR31917-31-3-2. IR28118-138- 2-3 had the best resistance and yielded 4.4 t/ha. IR18349-22-1-2-1-1, IR21820- 154-3-2-2-3, and IR25587-133-3-2-2-2 combined high yield (5.3 t/ha) and disease resistance.

Reaction of IRYN rices to some important diseases in Tamil Nadu, India. a

YS H BB ShB GlD

BG379-2 0 BR153-2B-10-1-3 0 BR40-300-2-1 3 BW295-4 5 BR-IRGA-409 3 IR18349-22-1-2-1-1 0 IR19672-140-2-3-2-2 0 IR21820-154-3-2-2-3 1 IR21848-65-3-2-2 0 IR22082-41-2 0 IR24637-38-2-2-1 0 IR25587-133-3-2-2-2 0 IR25603-20-2-1-3-2 0 IR25604-99-1-3-2-2 0 IR27316-96-3-2-2 0 IR27325-63-2-2 0 IR28118-138-2-3 0 IR28150-84-3-3-2 0 IR329723-143-3-2-1 0 IR31917-31-3-2 0 IR4744-295-2-3 0 RAU2004-669-2-13 (BIET2004) 3

RNR74229 5 RNR74802 0 RTN16-2-1-1-1 0

SI-PI 692106 3 UPR254-85-1-TCA 3 5

X.3-D.T. 5 IR42 3

Co 43 (local check) 5

3 7 3 3 7 3 3 3 3 7 5 3 1 5 5 3 3 5 3 3 5 7 5 5 5 7 5 3 5 3

3 5 3 5 3 1 3 3 3 3 5 3 3 3 5 1 1 5 5 3 5 5 7 5 3 5 5 3 3 1

5 3 3 5 7 3 3 1 3 3 3 3 3 3 3 3 1 1 5 3 3 7 7 3 3 7 5 5 5 3

5 5 3 5 7 3 5 3 3 3 5 3 3 1 1 3 3 5 5 3 3 3 5 3 5 7 3 5 5 3

a Scored by the Standard evaluation system for rice 1-9 scale: 1 = resistant, 9 = susceptible.

Genetic Evaluation and Utilization INSECT RESISTANCE

Resistance of Nephotettix virescens gene sources to Asian N. virescens populations

E. A. Heinrichs, H. R. Rapusas. and G. S. Khush, IRRI; S. Chelliah and A.M. Hanifa, Tamil Nadu Agricultural University, Coimbatore, India; M. M. Salleh and G. Von Vreden, MA RDI, Bumbong, Lima, Malaysia; W.S. Akib, MORIE Maros, Sulawesi, Indonesia; S. Pongprasert, Rai Research Institute, Bangkhen, Bangkok, Thailand; W. Katanyukul and C. Tayathum, Entomology and Zoology Division,

Bangkhen, Bangkok, Thailand; and N. C. Thuat, Central Institute of Plant Protection, Hanoi, Vietnam Tungro virus, vectored by green leafhopper (GLH) N. virescens, is a major problem where GLH-susceptible varieties are grown. IRRI and national program greenhouse screening has identified more than 1,300 cultivars with GLH resistance. Seven genes for N. virescens resistance have been identified in genetic analysis at IRRI and the Bangladesh Rice Research Institute, and

some of those genes have been incorporated into improved rice varieties. Although these varieties have been effective in controlling GLH, there is evidence that the levels of resistance conveyed by the different genes vary with location. We sought to determine the levels of resistance conveyed by the seven genes to local GLH populations in the Philippines (IRRI), India, Indonesia, Malaysia, Thailand, and Vietnam.

Resistance was determined in seedbox screening and nymphal survival tests. In


Field evaluation of rices for whitebacked planthopper (WBPH) and leaffolder (LF) resistance

K.S. Kushwaha and R. Singh, Entomology Department, Haryana Agricultural University Rice Research Station, Kaul 132021, Kurukshetra, India

WBPH Sogatella furcifera Horvàth has become a serious pest in Haryana. In 1984 kharif, an epidemic of the insect occurred. LF Cnaphalocrocis medinalis Gn. also is increasing in importance.

We evaluated 43 varieties received

from the All India Coordinated Rice Improvement Project for field resistance to WBPH and LF in 1984 kharif. Two 1-m-long rows of each variety with 10 hills/row and 1 seedling/hill were planted in two replications on 5 Jul. Susceptible TN1 was planted as a skip row after every 10 varieties and around the trial.

To encourage WBPH population, the border rows were sprayed with 0-0.2% methyl parathion at 10-d intervals starting the 1st week of August. WBPH damage was scored using the Standard evaluation system for rice. LF damage

Table 1. Reactions of seedlings in seedbox screening for GLH resistance, GLH Collaborative Project.

Reactions a in

Variety Gene Philippines India Indonesia Malaysla Thailand Vietnam (Hanoi) (IRRI) (Coimbatore) (Maros) (Bumbong Lima) TRRI EZD

Pankhari 203 ASD7 IR8 Ptb 8 ASD8 TAPL #796 Moddai Karuppan IR29 (resistant check) TN1 (susceptible check)

Glh 1 Glh 2 Glh 3 glh 4 Glh 5 Glh 6 Glh 7

– –

R R

MR MR

R MR MR

R S

S MR MR

R MR MR

R R S

R R

MR MR

R MR

R R S

S R S R R R R

MR S

MR R

MR R

MR R R

MR S

MR R

MR R

MR MR

R R S

R R

MR R R R

MR R S

a TRRI = Thai Rice Research Institute, EZD = Entomology and Zoology Division. R = resistant, MR = moderately resistant, S = susceptible.

the thrice-replicated seedbox screening test, varieties were infested with about 5 1 st- or 2d-instar nymphs/ seedling 7 d after sowing. Damage was rated by the Standard evaluation system for rice when 90-100% of susceptible TNl seedlings died.

In the survival test, three 7-d-old seedlings were transplanted per pot. Each variety was replicated five times with each pot as a replication. Pots were in a randomized complete block design and were covered with mylar film cages. Plants were infested with 10 1st-instar GLH nymphs/cage 23 d after transplanting. Surviving insects were counted 15 d later.

in India and Malaysia and resistant or moderately resistant at all other locations. IR8 (Glh 3) was susceptible in Malaysia and moderately resistant in other locations. The other varieties, except TNl, were resistant or moderately resistant at all locations. ASD7 was resistant in all locations except India, where it was moderately resistant. IR29 was resistant at IRRI, India, Indonesia, Thailand, and Vietnam (Table 1).

generally similar to those of the seedbox screening test. ASD8, which was resistant in the seedbox test at IRRI, Indonesia, and Malaysia, and moderately resistant in Thailand, had low nymphal survival at IRRI and in Indonesia and Malaysia, but moderately high survival in Thailand (Table 2). Survival on IR29 was low at IRRI and

Pankhari 203 (Glh 1 ) was susceptible

Results of the survival study were

Table 2. GLH nymphal survival at different locations, GLH Collaborative Project.

Survival a (%)

Philippines Indonesia Thailand (IRRI) (Maros) (TRRI)

Pankhari 203 Glh 1 2 a 0 a 66 bc ASD7 Glh 2 8 ab 32 b IR8 Glh 3 24 b 42 b 78 cd

40 ab

Ptb 8 glh 4 76 c 40 b 58 abc ASD8 Glh 5 14 ab 2 a 72 c TAPL #796 Glh 6 28 b 32. b 38 ab Moddai Karuppan Glh 7 74 c 34 b 32 a IR29 (resistant check) – 0 a 0 a 80 cd TN1 (susceptible check) – 80 c 74 c 94 d

a Av of 5 replications. Separation of means in a column by Duncan’s multiple range test at the 5% level; TRRI = Thai Rice Research Institute.

Variety Resistance gene

in Indonesia and Malaysia, but high in Thailand.

There was a distinct difference in the reaction of Pankhari 203 to GLH populations in Coimbatore, India, and Bumbong Lima, Malaysia. Pankhari 203 would not be used as a parent to

provide GLH resistance in India and Malaysia. ASD7, however, is resistant everywhere but in India, where it is moderately resistant and nymphal survival is low; therefore, it has good potential as a donor of GLH resistance.

8 IRRN 11 : 1 (February 1986)

Field reaction of rice varieties to WBPH and LF at Kaul, India.

Variety WBPH damage a LF damage

(0-9) (%)

RP2068-18-35 RP2068-17-3-7 RP2068-18-4-5 RP2068-18-2-6 RP2068-16-9-5 RP2068-18-4-7 RP2068-18-2-11 CO 29 Balamawee TN 1 T7 IET8770 IET8769 IET8868 (OR405-4) IET7800 IET837 1 IET8817 (CR372-48) RP2199-292-31 RP2199-84-2 RP2199-296-3 RP2199-286-26 BKNBR1088-83 T2005 Vaizhaeppoo Samba

CO 42 IR4707-106-3-2

RP2071-18-1-1 RP2071-22-5-3 RP2076-46-4-2 RP2069-3-4-1-2 RP2069-3-4-4-6 RP2069-3-5-2-2 RP2069-39-3-1-4 RP2068-12-1-8-1 RP2068-15-1-4-2 RP1579-26 RP1579-27 RP1579-28 RP1579-29 RP1579-47 RP1579-48 RP1579-53 RP1579-54

Swarudhan/Veluthachera -do- -do- -do- -do- -do- -do-

CO 13/CO 14 Donor Susceptible check Donor MTU4407/WGL 26888

-do- –

IR20/Shakti Phalguna/ARC6650

Phalguna/TKM 6 –

-do- -do- -do-

IR2030-203-3-1/RDl Donor Donor

RP31-49-2/Leb Mue Nahng Swarudhan/NLR9674

-do- IET6314/NLR9674 Swarudhan/Andrewsali

IR1888-156/IR2061-213-2

-do- -do- -do-

Swarudhan/Veluthachera

Phalguna/ARC6650 -do- -do- -do- -do- -do- -do- -do-

a + = did not flower, ++ = late flowering.

1 +

1 +

0 +

0.5 0.5 0.5 4 0.5 ++

4 9 5 7 7 4 5 4 1 6 7 5 5 4 2 2 8 4 4 4 4 1 +

1 +

1 +

1 +

1 +

1 +

5 7 5 5 4 4 4 4

4 3 1 6

11 12 9 5 6

21 4 4 6 9 9

11 1 8 2

11 4 8 7 2 5 7

22 11 10

9 4 5

10 11 4 3

12 9

10 8

24 11 33

was rated based on percent leaves damaged per 5 hills. Damage was rated the 3d week of September, when TN1 showed hopperburn.

RP2068-18-4-5, CO 29, IET8817 (CR372487), Vaizhaeppoo Samba, and RP 2069-344-6 were resistant to both insects (see table). T7, IET8770, RP2199-84-2, and RP1579-26 were resistant to LF. RP2068-18-2-6,

RP2068-18-3-5, RP2068-17-3-7,

RP2068-16-9-5, RP2068-184-7, T2005, RP2069-34-1-2, RP2069-3-5-2-2, RP2069-39-3-1-4, RP2068-12-1-8-1, and RP2068-15-1-4-2 were resistant to WBPH.

The International Rice Research News- letter (IRRN) invites all scientists to contribute concise summaries of significant rice research for publication. Contributions should be limited to one or two pages and no more than two short tables, figures, or photographs. Contributions are subject to editing and abridgment to meet space limitations. Authors will be identified by name, title, and research organization.

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

Varietal screening for leafhopper and planthopper resistance at Varanasi, India

D. S. Misra and K. D. Reddy, Department of Entomology and Agricultural Zoology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi 221005; and B. C. Misra, Division of Entomology, Central Rice Research Institute (CRRI), Cuttack, Orissa, India

We evaluated seedlings of 24 rices commonly grown by farmers in Eastern Uttar Pradesh and those from an upland rice project for resistance to leafhoppers Nephotettix virescens and N.

nigropictus, brown planthopper (BPH) Nilaparvata lugens, and whitebacked planthopper (WBPH) Sogatella furcifera.

Hoppers were reared on TN1. Ten seedlings per variety were grown in each 60- × 40- × 10-cm tray with 5-7 cm of soil. Resistant Ptb 33 and susceptible TN1 and Jelhore were included for comparison. Ten days after sowing, 8-10 2d- and 3d-instar nymphs each of BPH and WBPH and 3-5 leafhopper adults were released on each plant. Each species had three replications in separate trays. The trays were put in an aquarium covered with wire mesh.

Damage was rated by the Standard

evaluation system for rice when 90% of the TN1 plants died. Five cultivars had resistance to BPH, 11 to WBPH, 9 to N. virescens, and 8 to N. nigropictus. Only Ptb 33 was highly resistant to BPH (Table 1).

Cultivars with moderate resistance were studied for nymphal survival. Three replications of 1st-instar nymphs of each insect species were placed on 30- d-old plants in pots covered with glass chimneys. Percent nymphal survival, recorded 15 d later, was between 60 and 80% for all varieties but Ptb 33, on which 43-53% of nymphs survived (Table 2).


and yielded 0.5 t/ha more than TKM9, IR50, and ADT36 (see table). It has short stature and long, slender grains, and is resistant to brown planthopper, gall midge, and yellowing syndrome, a serious disease in Tamil Nadu.


Performance of IR64 at Tamil Nadu Rice Research Institute (TNRRI)

M. Subramanian, A. P.M. K. Sundararaj, and V. Aduthurai, Thanjavur District 612101, India

Sivasubramania, TNRRI,

IR64 (IR18348-36-3-3) was evaluated at TNRRI in the 1983 International Rice Yield Nursery-Early trial and in 1984 yield trials. IR64 matured in 110-115 d

Table 1. Varietal reaction to leafhoppers and planthoppers, Varanasi, India.

Variety Reaction a to

N. lugens S. furcifera N. virescens N. nigropictus

OR34-16 S Jaya MR CR202-2 S Culture 1 MR

IR8 MR Saket 4 S DR92 S

Mtu 17 S Nagina 22 S

CR132-168-73 S

RP79-24 S

RP79-27 S CR142-2-10 S RP79-5 S Cauveri S IR28 S Pusa33 S Jelhore S C7 306 S FH109 S IET5725 MR

TN 1 S Ptb 33 R

CR115-107 MR

MR S

MR MR MR

S MR

S S S S S S S

MR MR

S MR MR

S MR

S S

MR

MR MR MR

S S

MR MR MR MR

S MR

S S S S S S S S S S S S

MR

MR S

MR S

MR S S S

MR S

MR S S S S

MR S

MR S S S S S

MR

Table 2. Nymphal survival of rice leafhoppers and planthoppers on moderately resistant varieties at Varanasi, India.

Survival (%) of insect species a

N. lugens S. furcifera Nephotettix spp. Variety

Jaya 63 – 73 IR28 – 67 87

Jelhore 83 77 73 IR8 70 – 77

RP79-24 – – 70

OR34-16 – 67 73 CR202-2 – 80 73 Nagina 22 – – 87 Saket 4 – 80 80 DR92 – – 83 CR132-168-73 – 87 80 CR115-107 70 – Culture 1 60 70 – IET5725 67 77 – Cauveri – 57 – C7306 – 73 TN 1 97 100 100 Ptb33 43 47 53

–

–

a – = not studied; a mixed population of N. virescens and N. nigropictus was used.

a R = resistant, MR = moderately resistant, and S = susceptible.

Genetic Evaluation and Utilization AGRONOMIC CHARACTERISTICS

Performance of IR64 at TNRRI, Aduthurai, India .

Grain yield (t/ha) Flowering

Variety 1983 1984 kuruvai duration kuruvai (d)

Trial 1 Trial 2

IR64 3.4 5.6 5.3 65-70 TKM9 4.9 5.0 4.8 75-80 IR50 2.4 4.6 70-75 ADT36 – – 4.7 80-85

Genetic Evaluation and Utilization DEEP WATER

Elongation ability of deep water rice were sown in earthen pots with 8 kg soil flooded, and water was raised 10 cm/d at two nitrogen levels and 0 or 8 g urea fertilizer per pot. The for 9 d. A single seedling was taken

H.A. Quayyum, A. R. Gomosta, and M. Z. 5 replications had a pot each with 10 from each pot every 2 d to record Haque, Bangladesh Rice Research Institute, plants. Triple superphosphate and chlorophyll content and internode Joydebpur, Dhaka, Bangladesh muriate of potash were applied at elongation.

5 g/pot. Five weeks after sowing, the Elongation rate of all plants increased Deep water Habiganj Aman II seeds pots were placed in concrete tanks, for 4 d after flooding and then gradually


–

1. Plant height and internode elongation ability of Habiganj Aman II.

submergence depth rather than by N (Fig. 2). With added N, chlorophyll content. The no-N plants had lower content decreased and then increased to final plant height. slightly more than the initial content.

Chlorophyll content of the three Chlorophyll increased more rapidly in upper leaves of the no-N plants no-N plants than in those with added gradually increased during flooding N.

Pest Control and Management INSECTS

Whitebacked planthopper (WBPH) outbreak in Haryana, India

K. S. Kushwaha and R. Singh, HAU Rice Research Station, Kaul, Kurukshetra, Haryana, India

WBPH Sogatella furcifera Horváth has attacked rice in Haryana since the early 1970s, and severe outbreaks occurred in 1984-85. We surveyed field

populations of WBPH in villages in Karnal, Kurukshetra, Ambala, Jind, Hisar, and Sirsa Districts in mid-Sep, when pest incidence was high and rice was at panicle emergence stage. Sixty of the 85 villages surveyed had more than 70% infestation and 15 villages had 18% infestation (see table). WBPH population was 100-2,000/hill. PR106 was the most affected variety. Weather was generally warm and humid.

WBPH population intensity in Haryana, India, 1984-85.

Villages Villages (no.) with indicated intensity a

(no.) Severe Moderate Light District Block surveyed

Karnal Nilokheri 4 4 0 0 Indri 6 6 0 0 Karnal 3 2 1 0 Jundla 5 5 0 0 Assandh 6 4 1 1

Kurukshetra Pundri 15 13 1 1 Kaithal 7 7 0 0 Sewan 4 4 0 0 Cheeka 3 1 1 1 Pehowa 2 1 1 0

Ambala Ambala 2 1 1 0 Naraingarh 2 0 1 1 Bilashpur 1 0 1 0 Jagadhari 2 0 2 0

Sirsa Rania 12 5 4 3 Kalait 4 – 1 3

Hisar Tohana 4 4 0 0 Ratia 3 3 0 0

Total 85 60 15 10

no visible symptoms.

2. Change of total chlorophyll content of leaves of Habiganj Aman II during flooding.

decreased (Fig. 1). No-N plants were borer (YSB) damages rice from tillering to maturity. shorter than plants with N before flooding, but elongated more rapidly, National Agricultural Research Project YSB using egg masses as threshold indicating that ability of internodes to (NARP), Gujarat Agricultural University, criteria with scheduled control in 1983 elongate is influenced more by Navsari Campus, Navsari 396450, India and 1984 rainy seasons at NARP farm.

Need-based control of yellow stem YSB Scirpophaga incertulas Wlk.

M. S. Purohit, A. H. Shah, and S. Raman, We compared need-based control of

IRRN 11 : 1 (February 1986) 11

a Severe = fields with one or more hopperburned patches; moderate = fields with yellowing; light

The experiment was in duplicate plots (ABBA method) with seven replications. GR-11 seedlings were transplanted in 50-m 2 plots. Egg masses were counted in need-based plots at 10-d intervals. When 1 fresh egg mass was observed in any plot, all replications were sprayed with monocrotophos 0.36 kg ai/ ha. In schedule-based control plots, the same insecticide formulation was applied 15, 45, and 60 d after transplanting.

Percentage of deadhearts at maximum tillering, number of whiteheads at reproductive stage, and grain yield were recorded, and the data were statistically and economically analyzed.

In 1983, mean percentage of deadhearts was 2.9 in the need-based treatment and 6.4 in the schedule-based treatment (Table 1). The trend was similar in 1984. The number of whiteheads also was significantly lower in need-based than in schedule-based treatments. The need-based treatment had 10 and 15% higher yield in 1983 and

Virulence of whitebacked planthopper (WBPH) populations in South and Southeast Asia: report of a collaborative project

E.A. Heinrichs. H. R. Rapusas, and G.S. Khush, IRRI; S. Chelliah and K. Gunathilagaraj, Tamil Nadu Agricultural University, Coimbatore, India; S. Uthamorang, Aduthurai, Tamil Nadu, India; W. S. Akib, MORIF, Maros, Sulawesi, Indonesia; S. Y. Choi, College of Agriculture, Seoul National University, Suweon, Korea; S. Pongprasert, Rice Research Institute, Bangkhen, Thailand; W. Katanyukul, Entomology and Zoology Division, Bangkhen, Thailand; and N. K Huynh and T. H. Tien, University of Cantho. Vietnam

WBPH Sogatella furcifera Horváth outbreaks appear to have increased in frequency and severity throughout Asia. Resistant varieties, which should play a key role in WBPH control, have not been developed. More than 400 traditional varieties with WBPH resistance have been identified in greenhouse screening at IRRI and in national programs in South and


Table 1. Efficiency of need-based control of YSB compared with schedule-based insecticide application, Gujarat, India, 1983 and 1984. a

Mean percentage Mean no. Mean grain yield Insecticide deadhearts whiteheads (t/ha) application

1983 1984 1983 1984 1983 1984

Need-based 2.9 a 3.6 a 75 a 93 a 3.7 a 5.6 a Schedule-based 6.4 b 6.0 b 102 b 168 b 3.3 b 4.7 b

't' value 2.54 4.09 2.44 3.16 2.71 8.84

a Separation of means in a column at the 5% level.

Table 2. Economics of need-based control of YSB, Gujarat, India.

Total cost of Incremental Insecticide insecticides and Gross income Net gain over cost benefit application labor b ($/ha) ($/ha) check ($/ha) ratio (addi-

tional profit 1983 1984 1983 1984 1983 1984 per $ cost)

1983 1984

Need-based a 38 50 565 863 54 132 0.42 1.64 Schedule-based 36 36 511 730 – – –

a Three sprays were necessary in 1983 and four in 1984. b Labor cost for sampling and applying insecticides.

–

1984, and higher net return and cost threshold level per unit area should be benefit ratio (Table 2). determined.

The appropriate YSB egg mass

Table 1. Summary of damage ratings of varieties with genes for resistance in seedbox screening for WBPH.

Reaction a at

Variety Gene Philippines India Indonesia Korea Thailand Vietnam IRRI Tamil Nadu Maros Suweon Bangkok Cantho

N2 2 Wbph 1 R R R R R MR ARC10239 Wbph 2 R R R R R S

WC1240 Wbph 1 + 1 recessive R R R R R MR Colombo Wbph 2 + 1 recessive R R R R R MR TN1 None S S S S S S

IR2035-117-3 Wbph 1 + Wbph 2 R R R MR R MR

a R = resistant, MR = moderately resistant, S = susceptible.

Table 2. Feeding activity of WBPH female adults as indicated by honeydew excretion (area of honeydew spot in mm 2 ) a on varieties with different genes for resistance.

Honeydew spot (mm 2 )

Variety Philippines India Indonesia Korea Thailand Vietnam IRRI Coimbatore Maros Suweon Bangkok Cantho

N2 2 28 a 77 b 3 a 6 a 9 a 47 ab ARC10239 21 a 95 b 5 a 7 a 45 a 69 b

WC1240 44 a 14 a 26 a 2 a 41 a 23 a Colombo 27 a 37 ab 5 a 0 a 151 b 42 ab TN1 714 b 367 c 116 b 49 b 269 c 121 c

level. a Av of 5 replications. Separation of means in a column by Duncan’s multiple range test at the 5%

IR2035-117-3 10 a 8 a 4 a 0 a 46 a –

Southeast Asia. Genetics studies at IRRI have identified several genes for resistance to the Philippine population.

There have been reports of differential reactions of resistant varieties to WBPH populations in South and Southeast Asia. In breeding for WBPH resistance, it is important to select parents that have resistance to local populations. Materials for use in several countries should have resistance to a diversity of WBPH populations.

varieties with different genes for WBPH resistance to help breeders select parent varieties with broad WBPH resistance. IRRI-developed high yielding lines with WBPH resistance also were evaluated in several countries.

The gene sources given in Table I were evaluated in six countries using seedbox screening, feeding, and population growth tests. IR2035-117-3 is a resistant check. Its progeny — IRl5527-21-2-3, IR15529-253-2-2-2, and IR15795-151-2-3-2-2 — showed WBPH resistance in tests throughout South and Southeast Asia.

evaluation were resistant or moderately resistant at the various locations, except ARC10239 which was susceptible in Vietnam (Table 1). The other varieties were moderately resistant in Vietnam and most were resistant at the other locations.

All resistant varieties significantly reduced WBPH feeding (Table 2). At IRRI and in Indonesia, there was no difference among the resistant cultivars.

The survival test showed fewer WBPH on resistant varieties than on susceptible TN1, except on N22 at IRRI and in Vietnam (Table 3). Although ARC10239 was susceptible in seedbox screening in Vietnam, very few WBPH survived on it.

cultivars except N22 at IRRI significantly reduced WBPH populations below those on TN1 (Table 4). Among test cultivars, populations on N22 were generally among the highest. At IRRI, IR2035-117-3 had the lowest population and performed similarly in India, Korea, and Thailand.

We determined the response of

All gene sources in seedbox

In population growth tests, all

Table 3. WBPH survival a on varieties with different genes for resistance.

Survival (%)

Variety Philippines IRRI

India Coimbatore

Korea Suweon

Thailand

Entomology and Zoology Division

Bangkok

Thai Rice Research Institute Bangkok

Vietnam Cantho

N22 ARC10239

WC1240 Colombo TN1

IR2035-117-3

96 b 68 a 70 a 86 ab 82 ab 96 b

40 b 34 b 16 a 40 b 44 b 72 c

43 b 24 ab 20 a 19 a 19 a 60 c

10 a 18 a 12 a 10 a

68 b 6 a

66 b 66 b 58 b 42 a 58 b 96 c

48 bc 14 a

17 a 28 ab 70 c

–

a Av of 5 replications. Determined at 15 d after inoculation. Separation of means in a column by Duncan’s multiple range test at the 5% level.

Table 4. Population growth a of WBPH on varieties with different genes for resistance.

Population growth (no./pair)

Variety Philippines IRRI

India Coimbatore

Korea Suweon

Thailand

Entomology and Zoology Division

Bangkok

Rice Research Institute Bangkok

N22 ARC10239

WC1240 Colombo TN1

IR2035-117-3

61 b 24 a 17 a 23 a 28 a

104 c

11 a 0 a 0 a 0 a

202 b 0 a

8 a 11 a 4 a 4 a

44 b 9 a

219 c 226 c 163 b 125 a 233 c 782 d

307 cd 192 bc

33 a 126 b 86 b

559 d

a Av of 5 replications, determined at 30 d after inoculation. Separation of means in a column by Duncan’s multiple range test at the 5% level.

Data show that all the varieties with genes for resistance to the Philippine WBPH population also are resistant or moderately resistant in India, Indonesia, Korea, Thailand, and Vietnam. IR2035- 117-3, with Wbph 1 and Wbph 2, has been extensively used as parent at IRRI.

Many breeding lines developed from IR2035-117-3 were resistant at all of the locations tested. If differential responses of resistant varieties to WBPH populations throughout Asia are a constraint to breeding, it was not apparent in this study.

A carbon dioxide-cone (CO 2 NE) sampler for arthropods in flooded rice

G. B. Aquino and E. A. Heinrichs, Entomology Department, IRRI

We developed a CO 2 NE arthropod sampler for obtaining absolute estimates in research plots.

The sampler consists of a portable CO 2 tank with a rubber hose to deliver gas, an aluminum cone, a strainer with an attached plastic vial with a nylon mesh bottom, and an enclosure ring.

The aluminum cone is carefully placed over a rice hill followed by the enclosure ring. The cone is then filled with CO 2 (see photos). A rubber stopper seals off the opening at the top of the cone. After 1-2 min the cone is removed. The arthropods that fell onto the water within the enclosure ring are scooped up with the strainer and collected in the attached vial. Arthropods that fall between tillers are flushed out with water. When sampling is complete, the arthropods in the vial are rinsed out through another vial with 75% alcohol and brought to the laboratory.


Arthropod density in three lowland rice varieties determined by FARMCOP and CO 2 NE insect samplers, a IRRI, 1984.

The CO 2 NE sampler.

& , I *kt* "

Filling the cone with CO 2 .

Scooping the arthropods on the water surface.


Arthropods (no./5 hills on indicated variety)

Sampler Brown planthopper Green leafhopper Green mirid bug Wolf spider Nilaparvata lugens Nephotettix spp. Cyrtorhinus lividipennis Lycosa pseudo-

IR22 IR28 IR36 IR22 IR28 IR36 IR22 IR28 IR36 annulata

IR22 IR28 IR36

FARMCOP 7.2 a 4.0 a 1.6 a 44 a 2.8 a 13.6 a 17.6 a 12.2 a 8.4 a 9.2 a 6.4 a 5.2 a CO 2 NE 5.2 a 4.8 a 3.2 a 21 b 4.4 a 15.6 a 22.8 a 17.2 a 13.6 a 9.2 a 8.4 a 7.6 a

a In a column, means followed by the same letter are not significantly different according to t-test (P < 0.01).

The CO 2 NE sampler is inexpensive hills. and easy to handle. A tank containing In a field trial comparing the CO 2 NE 22.5 kg of CO 2 costs about $10 and is and a formerly used FARMCOP enough to sample 2,000 or more hills. In suction machine, there was almost no the field, a portable tank with 300 ml of difference in the number of arthropods CO 2 , can be used to sample 30 to 40 collected (see table).

Brown shield bug attack on rice

P. B. Chatterjee, entomologist, All India Coordinated Rice Improvement Project, Rice Research Station, P. O. Chinsurah R. S., Hooghly, India

A pentatomid or shield bug damaged rice in Dinajpur District, West Bengal, in 1983. Dinajpur is between 25.2° and 26.5°N and 88° and 89° E. Wet season lowland rice is the principal crop, but summer and pre-kharif rice crops are increasing.

Two species of the pentatomid bug were identified by the Zoological Survey of India, Calcutta, as Dolycoris indicus Stal and D. baccarum Linn (see figure). Nymphs and adults damage rice by sucking plant sap and milk from panicles in dough stage. Panicle sterility averaged 10%. Populations were highest in Apr, when it was not unusual to find 2–3 insects per plant.

Rice hispa in Burdwan, West Bengal in only a few areas of West Bengal. In 1984 kharif there was a severe hispa

D. K. Banerjee and D. K. Nath, Entomology Section, Government of West Bengal, Adaptive Crop Production Research Station, Data from Burdwan District, which Kalna Road, Burdwan, West Bengal, India had 24,575 ha attacked by hispa,

Rice hispa Dicladispa armigera occurs The first developed just after

outbreak on 62,341 ha of rice in 5 southern districts.

showed 4 broods during 1984 kharif.

D. Sundararaju, Indian Council of Agricultural Research Complex for Goa, Ela, Old Goa, India

Influence of planting time and rainfall on gall midge (GM) incidence and rice yield in Goa, India

transplanting in mid-Aug, the second in the first week of Sep, the third in mid- Sep, and the fourth (only on late- transplanted crops) in the first week of Oct .

Periodic incidence of adults on the leaves indicated successive broods. Grubs mined between the leaf epidermis, turning 1/3 to 1/2 white. At late-stage infestation, fields developed a blighted

look. Early generations caused patchy damage but cumulative damage by successive generations covered whole fields. Crop-cuts (10 m 2 ) were taken from short-duration Ratna and long- duration Pankaj. Yield loss was 23% for short-duration and 17% for long- duration varieties.

Weather conditions may have encouraged the hispa outbreaks. Most

days were rainy during sowing, which prevented the normal dry seeding. Rainfall was higher than normal, but the number of rainy days and the duration of bright sunshine hours were the same. Sunny weather interrupted by quick showers. no summer plowing, and lack of insecticide application may have increased hispa incidence.

Virulence of green leafhopper (GLH) colonies from Luzon, Philippines, on IR36 and IR42

H. R. Rapusas and E.A. Heinrichs, Entomology Department, IRRI

In 1979, we surveyed farmers' fields in the Philippines to determine if there were GLH Nephotettix virescens biotypes virulent on the resistant varieties being grown. Results generally indicated that biotypes were not a problem. We repeated the survey in several Luzon provinces in 1984.

GLH adults were collected in Nueva Ecija, Tarlac, Pangasinan, La Union, Ilocos Sur, Ilocos Norte, and Abra and grouped by towns and varieties from which they were collected. Ten colonies were reared on susceptible TN1 in the greenhouse for two generations. A TN1 colony maintained in the greenhouse for more than 50 generations was included in the test. We tested the ability of each colony to develop a population on resistant IR36 and IR42.

Six-day-old seedlings of the test varieties were transplanted at 5 seedlings per pot in 10-cm-diameter clay pots. Two weeks after transplanting, each pot was enclosed in a mylar film cage to keep out other insect pests, parasites, and predators. Ten days later, the plants were inspected and any arthropods present in the cage were removed. Three pair of 3-d-old GLH adults from each of 11 colonies were introduced in each cage, replicated 5 times. The surviving insects were counted 25 d later.

than the greenhouse colony on IR36 or IR42 indicated an increase in virulence of that colony (see table). Colonies from all locations except Cuyapo. Nueva

A colony that was significantly bigger

Populations of GLH colonies from Luzon, Philippines, when reared on IR36 and IR42.

Colony Variety from

which collected

Capas, Tarlac Guimba, Nueva Ecija Cuyapo, Nueva Ecija Umingan, Pangasinan Santo Tomas-San Jose, Nueva Ecija Bauang, La Union San Fernando-Bacnotan, La Union Santa Cruz-Bantay, Ilocos Sur Paoay-Badoc, Ilocos Norte Pidigan, Abra Greenhouse

IR36 IR36 IR42 IR42 IR42 IR42, IR36, traditional IR36, IR42, traditional IR42, traditional IR42, Wagwag I R42 TN 1

Progeny/3 females a on

IR36 IR42

130 abcd 164 bcd

91 abc 152 bcd 207 d 143 bcd 109 abc 176 cd 152 bcd 82 ab 57 a

131 ab 204 bc 178 bc 127 ab 227 c 472 d 221 c 162 bc 155 abc 184 bc 89 a

a Separation of means in a column by Duncan’s multiple range test at the 5% level.

Ecija; San Fernando-Bacnotan. La Union; and Pidigan, Abra, were more virulent on IR36 than the greenhouse colony. On IR42, all colonies except those from Capas, Tarlac; Umingan, Pangasinan; and Paoay-Badoc, llocos Norte, were more virulent than the greenhouse colony.

indicate that GLH colonies collected in most of the provinces were more virulent than the greenhouse colony.

In contrast to our 1979 survey, results

Populations were about double those of the greenhouse colony on both IR36 and IR42. Therefore, GLH biotypes are developing in the Philippines.

Because IR36 and IR42 have low level of resistance to tungro virus (RTV). but have resistance to the vector GLH, there is the potential for higher RTV incidence on IR36 and IR42 in the locations where GLH colonies are most virulent.

We assessed damage caused by GM Orseolia oryzae (Wood-Mason) and its impact on grain yield in 1981 and 1982. Jaya was planted at 2-wk intervals in 40- m 2 plots with 5 replications beginning in Jun and ending in Jul. No insecticide was applied. GM damage was recorded 30, 45, and 60 d after transplanting (DT)

The International Rice Research Newsletter (IRRN) invites all scientists to contribute concise summaries of significant rice research for publication. Contributions should be limited to one or two pages and no more than two short tables, figures, or photographs. Contributions are subject to editing and abridgment to meet space limitations. Authors will be identified by name, title, and research organization.


2. Relation between GM infestation and grain yield at Goa, India, 1981.

and at harvest. Rainfall and daily light trap catches of GM were recorded from Jun to Oct 1981 (Fig. 1).

The early planted crop had no GM damage up to 45 DT, and GM infestation later had minimal impact on grain yield. GM attacked late-planted crops at 30 DT and significantly reduced yield (see table). GM infestation at 30 DT in 1981 was significantly and negatively correlated with grain yield (r = -0.694) (Fig. 2).

about 2 mo after peak rainfall, which may indicate probable GM outbreak. Therefore, rice planted early (Jun) in the

infestation than late crops.

1. GM population and rainfall pattern at Goa, India, 1981. Peak GM population was in Sep.

GM infestation and grain yield of different plantings, Goa, India, a 1981.

Silvershoot (%) monsoon has better chance of escaping Planting date 30 DT 45 DT 75 DT Grain yield (t/ha)

1980 1981 1980 1981 1980 1981 1980 1981

7 Jun 0 a 0 a 0 a 0 a 0 a 0 a 6.9 a 5.1 a Individuals, organizations, and media are 22 Jun 0 a 0 a 0 a 0 a 0 a 15 b 6.2 a 4.7 b 7 Jul 0 a 3 b 6 b 30 b 23 c 20 c 4.7 b 3.2 c

22 Jul 6 b 23 c 15 c 32 b 11 b 29 d 4.2 b 1.6 d excepts from articles in the IRRN. invited to quote or reprint articles or

a Separation of means in a column at 5 % level.

Oviposition of rice whorl maggot (RWM) in wet seedbeds

J. P. Bandong and J. A. Litsinger, Entomology Department, IRRI

RWM Hydrellia philippina Ferino is a major pest of irrigated rice in central Luzon, Philippines. Farmers often spray their wet seedbeds several times, even a few days before pulling the seedlings (20-25 d after seeding [DAS]). Late

spraying may kill RWM eggs laid in the seedbed before transplanting. Perhaps RWM control by foliar sprays after transplanting is inadequate because of seedbed infestation.

RWM eggs were monitored at 3d intervals from 7 to 24 DAS on 50 randomly selected plants 0, 10, 20, 30, 100, 130, 150 cm from the edges of 7 farmers' seedbeds. Wooden planks were set over the seedbeds so plants could be

removed without disturbing the rest of the seedbed.

Most eggs were laid on the edges of seedbeds (Fig. 1), which indicates that RWM is attracted to the open standing water around seedbeds (Fig. 2a) but will lay a few eggs in the closed canopies of seedbeds, on direct-seeded lowland rice, or on plants growing over azolla.

rooted seedlings along the edges of Central Luzon farmers leave the deep-


seedbeds (Fig. 2b), and therefore carry insignificant numbers of RWM eggs to the field. Most infestation, therefore, begins after transplanting.

1. RWM egg distribution sampled from 9 flooded, wet seedbeds, Zaragoza, Nueva Ecija, Philippines, 1984.

Complete slide sets of photos printed in Field problems of tropical rice, revised 1983, are available for purchase at $50 (less developed country price) or $60 (developed country price), including airmail postage and handling, from the Communication and Publications Department, Division R, IRRI, P.O. Box 933, Manila, Philippines. No orders for surface mail handling will be accepted.

2a. Wet seedbeds showing standing water between adjacent beds. 2b. Wet seedbeds after seedlings are pulled, leaving the borders.

Pest Control and Management DISEASES

Spread of rice tungro spherical virus (RTSV) in Bicol, Philippines

V. M. Aguiero, N. B. Bajer, G. B. Jonson, and H. Hibino, Plant Pathology, Department, IRRI

Tungro (RTV) is a disease complex associated with rice tungro bacilliform virus (RTBV) and RTSV. Previous

studies showed that susceptible varieties with RTV symptoms were generally infected with both RTBV and RTSV and that those without symptoms often- were infected only with RTSV.

To confirm the occurrence of RTSV and identify vector species, Nephotettix virescens, N. nigropictus, and Recilia dorsalis were collected from rice fields in Bicol, Philippines, in Feb and Mar 1985.

Vector populations were high, but RTV incidence was low or nonexistent. The vectors were allowed overnight inoculation access on TN1 seedlings in test tubes. All inoculated seedlings were tested in ELISA for RTBV and RTSV 14–21 d after inoculation.

In about 32 ha of rice fields in 7 municipalities, leaf samples were collected from some rice plants with


Infectivity of RTV vectors a collected in rice fields in Bicol, Philippines, Feb and Mar 1985.

Vectors (no.) transmitting RTBV (B) and RTSV (S) RTV Stage of

Location Variety infection collected N. virescens N. nigropictus (%) vectors

R. dorsalis

B+S B S None B+S B S None B+S B S None

Cagsawa, Albay IR42 0 Adult 1 2 0 31 0 0 0 60 1 0 0 2 Nymph 0 0 0 8 0 0 0 17 –

Ligao, Albay Masuri 5 Adult 0 0 3 26 0 0 2 Nymph 1 0 3 14 0 0 0

9 – – – –

Polangui, Albay IR50/unknown 0 Adult 0 0 1 6 0 6 1 6 1 0 0 1 1 – – – –

Nymph 0 1 1 8 0 0 0 Pili Camarines Sur IR29/IR58 0 Adult 0 0 0 1 0 0 7 64

1 – – – –

Nymph – 0 0 0 San Fernando, Unknown 0 Adult 0 0 0 16 0 0 0 19 0 0 0 1

2 – – – –

Camarines Norte Nymph 0 0 0 8 0 0 0 Daet, Camarines Norte IR42 0 Adult 0 0 0 13 0 0 0 31 –

5 – – – –

Nymph 0 0 0 1 0 0 0 Talisay, Camarines Norte IR42/unknown 0 Adult

2 – – – 1 0 0 24 0 0 0 44 –

Nymph –

– – –

– – – – – – –

– – – –

– – – – – – – – – – – – – –

Total 3 3 8 156 0 0 10 261 2 0 0 4

a Field-collected vectors were allowed to feed on TN1 seedlings and the inoculated seedlings were tested in ELISA for RTV.

RTV-like symptoms and tested in ELISA. Leaf samples from Ligao municipality reacted positively to RTBV + RTSV and RTSV. Although the presence of RTV was not confirmed, some vectors collected in other municipalities transmitted RTBV + RTSV and RTSV (see table). At Pili, Camarines Sur, N. virescens populations

were very low, but N. nigropictus population was high. More than 10% of N. nigropictus transmitted RTSV.

Of 172 N. virescens tested, 3 transmitted RTBV + RTSV, 3 transmitted RTBV alone, and 8 transmitted RTSV. Of 271 N. nigropictus tested, 10 transmitted RTSV and none transmitted RTBV. Of six R.

dorsalis tested, two transmitted both viruses.

The results indicate that RTSV is spreading as an independent disease in Bicol and that both N. nigropictus and N. virescens are carriers. RTSV also occurs in rice fields where RTV incidence is very low or nonexistent.

A new rice disease in Manipur, India

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

A new rice disease has been identified in Manipur. The disease appears at panicle emergence, when the glume develops a whitish, powdery growth. If the infection occurs early, the grains become chaffy.

The pathogen was isolated from fresh, diseased glumes on potato dextrose

Susceptibility of panicles at different development stages to Oospora, Iroisemba, Manipur, India.

Panicles Panicles Panicle stage inoculated infected

(no.) (no.)

Emerged 20 0 Milk 20 20 Dough 20 4 Mature 2 0

agar. Young panicles were inoculated with a 7-d-old culture of the pathogen. The pathogen was identified as Oospora oryzetorum, which produces coenocytic, branched, hyaline mycelium. Conidia are hyaline. 1-celled, globose, and 2.3 ×

Reaction of green leafhopper (GLH)- resistant varieties to rice tungro virus (RTV) complex

E. R. Tiongco, R. C. Cabunagan, and H. Hibino, Plant Pathology Department, I R R I

We tested ARC11554, ASD7, Gam Pai 30-1 2-1 5, Gam Pai 30-12-30, Habiganj DW8, Jhingasail, Palasithari, and Ptb 18 for reaction to RTV-associated viruses. All the varieties except Habiganj DW8 were resistant to GLH. Single test plants were planted in clay pots and enclosed in mylar cages. One month after planting they were inoculated for

3.5 µ in diameter. Panicles at different development

stages were sprayed with mycelial bits and a spore suspension prepared from a 10-d-old culture. Milk stage was most susceptible to the disease (see table).

24 h with l, 5, 10, 20, and 30 RTV viruliferous Nephotettix virescens per plant.

18 had low infection with rice tungro bacilliform (RTBV) + rice tungro spherical (RTSV) viruses or RTBV alone, regardless of the number of GLH per plant. That indicated stability of their resistance to RTV complex. RTBV infection of ASD7, Gam Pai 30-12-15, Gam Pai 30-1 2-30, and Palasithari increased with the number of viruliferous GLH per plant (see figure). Jhingasail had mild yellowing and stunting but high RTBV + RTSV

ARC1 1554, Habiganj DW8, and Ptb


Reaction of GLH-resistant rices to RTV complex when inoculated with different numbers of viruliferous GLH per plant.

infection. ASD7 had severe yellowing and RTBV alone even with high varieties may not be a virus source for and stunting but high RTBV infection. insect pressure, and the spread of the disease. Furthermore,

RTV resistance increased insect pressure. correlated with resistance to the vector, Results indicate there are two types of • increasing RTBV infection with resistance to RTV complex is not always

• high resistance to RTBV + RTSV In the latter case, however, infected as shown by Habiganj DW8.

Rice gall dwarf virus (GDV) outbreak in West Guangdong Province, China

Faan Hweichung and Zhang Shuguang, South China Agricultural University; Xie Shuungda, Zhou Lianggao. and Liu Chaozhing, Guangdong Academy of Agricultural Sciences; and Liu Xiaurong. Guangdong Agricultural Bureau, Xinyi County Agricultural Bureau, China

In 1981, an unknown rice disease occurred on 7,3 10 ha in West

You 2, Shan You 6, and Shan You 30 cincticeps (Uhler), and N. virescens were very susceptible, as were some local (Distant) transmitted the disease. Based varieties. on the characteristic gall, size of the

Electron microscopy showed that virus particles, and vectors, the disease polyhedral particles 60 nm in diameter was considered to be GDV, which were associated with the diseased plants. occurs in Thailand and Malaysia. Recilia dorsalis (Motsch), Nephotettix

Breakdown of Xa 4 gene for the tarai belt of Uttar Pradesh, where it resistance to bacterial blight (BB) at causes up to 80% yield losses. Incidence Pantnagar, India is increasing, and in 1982 and 1983 some

previously resistant varieties were Guangdong. By 1982, the disease had spread to 33,333 ha. Disease incidence was 30-40% and caused losses of 1.9 to University of Agriculture and Technology, resistance against the Pantnagar race of 4.5 t/ha. Symptoms were stunting, dark Pantnagar 263145, India the pathogen, we artificially field- green leaves, small light green galls on screened 101 entries, including leaf blades and sheaths, and low BB caused by Xanthomonas campestris international differentials for BB, tillering. Hybrid rices Shan You I, Shan pv. oryzae is a major disease of rice in promising IRRI varieties, elite strains

M. P. Pandey, H. Singh. and S. C. Mani, Plant Breeding Department, G. B. Pant To identify reliable donors of

infected.


from the All India Coordinated Rice Improvement Program, popular high yielding varieties from Uttar Pradesh, and some resistant lines from hill germplasm maintained at Pantnagar.

The entries were sown 10 Jul 1984 and transplanted 30 Jul; each was in 2 9 rows at 20- × 15-cm spacing. Recommended fertilizers and irrigation were applied and plots were kept weed free. Forty-five days after transplanting, five plants in each row were clip- inoculated with naturally occurring inoculum. Disease reaction was scored using the Standard evaluation system for rice (SES).

Table 1. BB reaction of rice varieties at Pantna- gar in 1984 kharif. SES score

0 1 3 DV85, BJ1, UPRB30, UPRB31, IET4141 5 Kinmaze, Tetep, lR29, IR43, IR50, IR54,

7 IR8, Javal4, 70x45, IR22, IR23, 1R38,

Variety or elite strain – –

UPRH300, RP633, RP633-9-8-1

IR42, IR48, IR52, UPRH137, RP633-519- 1-1-1

9 IR1545-339-3-2, Kogyoku, Kuntlan, T(N) 11, Nagina 5, DR92, IR30, IR32, IR36, IR44, IR45, IR46, IR56, TKM9, Bala, Govind, Pusa 33, Saket 4, Ratna, Prasad, IR24, Pant Dhan 4, Jaya, T3, Tilakchan- dan, UPRH93, UPRH130, UPRH153, UPRH166, UPRH216, UPRH245, UPRH246, UPRH247, CR167-7, CR200- 788-3, AD9246, OR173-1-1, RP1036-35- 2-5-1-1, PR103, Pusa 205-15-1, CR163- CRRP 56, CR75-93 Mut. 11-4, OR147-1- 137, RP1575636-6-1, RP1775-243-719, OR79-21, SKL6, OR131-5-8, HPU804, BPT1235, BIET236, AAU49-31-2, RP79- 104, UPR254-24-1-1, UPK10344-2, NDR301, NDR302, KR1047, PAU4056- 53-5, NSRP II Late, BAU4040-1, UPR81- 44, BK670, NRL326-3, Rasi, Camposelak,

28-4-2, LZN, IR20, Sayaphal, RP2151- TKM6, RW9-9, RP825-24-9-1, RP975-

40-1, OR164-5, RP1667-301-1196-1562, RP1451-17124319

Effect of bulky organic manures on sheath blight (ShB)

C. P. D. Rajan, assistant plant pathologist, and G. V. Reddy, senior scientist (Agronomy), Agricultural Research Station (ARS), Maruteru, Andhra Pradesh, India

ShB is an important rice disease in Andhra Pradesh. Applying bulky organic manures has been reported to enhance soil microbiological activity, which may increase ShB. We evaluated the effect of organic manure on ShB incidence at ARS in 1983 kharif.

manures (see table) were incorporated 15 d before transplanting. Fertilizer application was adjusted to 100-30-30 kg NPK/ ha. The experiment was in a randomized block design with four replications. Highly ShB-susceptible MTU6024 was planted in 5.8- × 3.4-m plots at 20- × 1km spacing. Natural disease incidence was recorded at dough Stage.

Incorporating neem cake, castor cake, rice straw, green leaf (Gliricidia

Different amounts of 5 bulky organic

20 IRRN 11: 1 (February 1986)

Table 2. BB reaction of some resistant rices at Pantnagar, 1982-84.

Gene BB reaction (0-9 a

Variety for resistance 1982 1983 1984

TKM6 Xa 4 3 3 9 Govind Xa 4 3 5 Prasad Xa 4 5 5 9

IR22 IR20 Xa 4 3 5 9

Xa 4 5 7 7 BJ1 xa 5 3 3 3 IET4141 xa 5 3 3 3 DV85 xa 5 + Xa 7 3 3 3 Pant Dhan-4 not known 5 5 9 UPRB30 -do- 3 3 3 UPRB31 -do- 3 3 3 TN1 No gene 9 9 9

Govind and Prasad, which were bred from TKM6 at Pantnagar and possess the Xa 4 gene for resistance to BB, had susceptible reaction (Table 1). This indicates that a new race of the BB pathogen that will break down resistance conferred by the Xa 4 gene may have evolved (Table 2). The lines BJI, DV85, UPRB30, UPRB31, and IET4141 were resistant. BJ1 and

a Scored by SES.

IET4141 have the xa 5 gene for resistance and DV85 has xa 5 and Xa 7 genes. These sources of resistance appeared to be the only reliable sources among rices adapted to Pantnagar conditions. They are being used in the breeding program.

Effect of bulky organic manures on ShB and rice yield, a Maruteru, India.

Manure Disease Grain Straw

Dosage/ha index yield yield (%) (t/ha) (t/ha)

Neem cake Neem cake Castor cake Castor cake Rice straw Rice straw Green leaf Green leaf Farmyard manure Control

F test CD @ 5% CV%

250 kg 500 kg 250 kg 500 kg 2t 6t 2t 8t 8t

–

68 69 65 68 67 66 69 66 67 67 ns – 6.2

4.4 4.5 4.7 4.9 4.6 4.1 4.8 4.8 4.4 4.5

0.3 5.8

s

6.4 6.5 6.8 6.4 6.5 6.5 7.2 7.2 7.3 7.3 ns

8.9 –

a ns = nonsignificant, s = significant.

muculatu), or farmyard manure did not the treatments. Straw yields were affect ShB incidence. Grain yields, similar. Yield variations were attributed however, differed significantly among to reasons other than ShB incidence.

Maize — a new host of rice gall Faan Hweichung, South China Agricultural dwarf virus (GDV) University; and Liu Xiaurong, Guangdong

Agricultural Bureau, Xinyi County Xie Shuangda, Zhou Lianggao, and Liu Agricultural Bureau, China Chaozhing, Guangdong Academy of Agricultural Sciences; Zhang Shuguang and We studied the host range of GDV in

1983 in Guangdong Province, China. Eight plant species grown in pots were confined with 1-5 viruliferous zigzag leafhoppers Recilia dorsalis Motsch per plant until the vector died (34 d). Maize plants also were inoculated with green leafhopper Nephotettix cincticeps. Disease symptoms developed 15-25 d after inoculation. Plants without symptoms were observed for 5-6 mo.

GDV infected wheat ( Triticum aestivum ), oat ( Avena sativa ), wild rice ( Oryza rufipogon ), Japanese grass (Alopecurus aequalis), and maize ( Zea mays ). Small galls developed on field grass ( Leptochloa chinensis ), but further confirmation is needed. Echinochloa crus-galli and Leersia hexandra did not have virus symptoms (see table).

Maize is a new host of GDV. Both zigzag and green leafhoppers

Host range of GDV in Guangdong, China, 1983. a

Zigzag Plants Plants Host leafhopper inoculated infected

per plant (no.) (no.)

Triticum aestivum Avena sativa Oryzae rufipogon Alopecurus aequalis

Zea mays Leptochloa chinensis Echinochloa crus-galli

Leersia hexandra

1 1 4 5 3 7 3 3 3 1

17 15

6 3

12 5 5 5 5

15

2 3 3 2 1 1

small galls 0 0 0

a Nephotettix cincticeps were used to inoculate the virus.

transmitted GDV to maize. Symptoms 1.5 cm long and 0.25 cm wide. Stunting developed 28 d after inoculation. Small, was not serious. The results were light green galls appeared on the leaf confirmed when rice plants exhibited veins, enlarged, and became waxy white. typical symptoms after back- Some galls formed vein swellings up to inoculation.

Rice diseases on the Godavari Delta and West Godavari Districts. Surveyors

C. P. D. Rajan, assistant plant pathologist, visited 69 villages and talked with 86 Agricultural Research Station, Maruteru, farmers in West Godavari, and visited Andhra Pradesh, India 31 villages and talked with 35 farmers in

We surveyed rice disease status in 1983 • Blast (Bl), which only occurs in rabi, 1984 kharif, and 1984 rabi in East rabi, sheath blight (ShB), and

East Godavari.

Disease incidence a on different rices in Andhra Pradesh, India, 1983-84.

bacterial blight were major diseases, and caused substantial yield losses.

• Tungro (RTV) occurs sporadically, but southern coastal districts had RTV epidemics in 1984 kharif.

• IR50 is highly susceptible to Bl. Applying heavy N doses (60-140 kg N/ ha) increased Bl disease seventy. Rabi varieties BPT1235 and IR62

Disease incidence have Bl resistance (see table). • Stem rot caused by Sclerotium

Variety Bacterial Blast Tungro Sheath Stem rot oryzae, brown spot caused by blight blight Helminthosporium oryzae, and

Rabi sheath rot caused by IR50 IET1444 BPT1235 IR62

IR36 Prabhat

Mahsuri MTU5 249

RP6-17

– VS – M – S SL

– SL M –

– M – –

M – Acrocylindrium oryzae were – SL

SL M S –

SL SL – –

sometimes observed, but caused – M – S – negligible losses.

– – –

– – – BR3 reaction to multiple disease –

– –

– – M – infection

MTU7029 SL – Kharif

– S – MTU5249 – – – M – MTU4870 MTU2077 M

M –

MTU2067 M

M M

MTU6024 M

SL IR42 SL

M –

Jaya SL Mahsuri SL Swarna Mahsuri SL IR62 M – – S –

a SL = slight, M = moderate, S = severe, VS = very severe.

– – – – – – – –

RP6-17 – – –

– – – – – – – – – – – – – – – –

– – – –

A. H. Mondal and S. A. Miah, Plant Pathology Division, Bangladesh Rice Research Institute, Joydebpur, Gazipur. Bangladesh

Rice fields often are infected by more than one disease. We evaluated BR3 under multiple disease infection. BR3 seedlings were transplanted in 48 rows of 10 hills each. The field received the recommended 80-60-40 kg NPK/ha.


severity were measured by counting infected tillers from 10 randomly selected hills from each plot and scored using the Standard evaluation system for rice.

All the fungicides checked ShB intensity (see table). Validamycin 3L at 1 litre/ha and carbendazim 500 g/ha performed similarly and significantly better than other treatments (see table).


Sheath blight (ShB) control

V. P.S. Dev and C. A. Mary, Regional Agricultural Research Station, Pattambi, Kerala 679306 India

ShB caused by Thanatephorus cucumeris (Frank) Donk is a serious rice disease in Kerala. Under the All India Coordinated Rice Improvement Project, we evaluated different fungicides for ShB control in a field trial with 1R50. There were seven treatments with four replications in a randomized block design. Plants were inoculated 25 d after planting with ShB pathogen that was multiplied on unhusked rice grains. Fungicides were sprayed 40 and 50 d after planting. Disease incidence and


Table 1. Disease index of four diseases and their interaction on BR3 in 1984 aus, Joydebpur, Bangladesh.

Average disease index a

Inoculant BB ShB ShR LSc

Without ShB With ShB Without ShB With ShB Without ShB With ShB Without ShB With ShB

0

2 (ShR)

3 (BB) 4

(LSc) 2, 3

2, 4

3, 4

2, 3, 4

3.67 d A

2.67 d A

6.33 a A

3.00 d A

5.00 b A

4.33 c A

5.00 b A

5.00 b A

2.67 b A

3.00 b A

3.00 b B

3.00 b A

6.00 a A

2.33 b B

2.33 b B

5.33 a A

2.67 a B

0.0 c B

1.67 ab B

0.33 c B

0.0 c B

0.0 c B

0.33 c B

1.00 b B

3.33 e A

5.00 cd A

5.00 cd A

4.33 de A

6.33 a A

5.33 bc A

5.83 ab A

6.00 ab A

0.67 f A

4.33 b A

2.33 cd A

1.00 ef A

3.00 c A

2.67 c A

1.67 de A

5.67 a A

0.33 d A

4.33 ab A

1.67 c A

2.00 c A

3.67 b A

3.67 b A

1.67 c A

4.67 a A

3.67 d A

2.33 e A

5.00 c A

5.33 bc A

3.67 d A

5.00 c A

6.67 a A

6.00 b A

2.67 c A

3.00 bc A

2.67 c B

5 .00 a A

2.67 c A

3.67 b B

5.00 a B

5 .00 a A

a Data are averages of 3 figures based on Standard evaluation system for rice. 0 = no disease inoculation, 2 = ShR, 3 = BB, and 4 = LSc. Small letters in a column indicate differences among treatments. Capital letters in a row indicate difference with and without ShB.

Table 2. F values of yield characters of BR3 with multiple disease infection, Joydebpur, Bangladesh. a

F values

SV Fertile Filled 1,000- tiller grain grain (%) (%) wt (g)

Multiple infection 2.01 ns 1.08 ns 2.13 ns

No disease vs ShB 12.38** 19.81** 14.54** Multiple infection 2.12 ns 1.07 ns 2.09 ns

× no disease vs ShB

CV % 10.63 11.07 4.11

a Diseases were ShB, ShR, BB, and LSc. ns = insignificant F value; ** = 1% significant F value.

Plots were inoculated with one to four diseases using a completely randomized design. Subplots were sheath blight (ShB) and no ShB inoculation. Plants were inoculated with ShB and bacterial blight (BB) inocula at maximum tillering, and with sheath rot (ShR) and leaf scald (LSc) at flag leaf stage.

Reactions were significantly different among treatments and with and without ShB (Table I). When LSc infection was high, BB infection was lower. ShB was highest in ShB-inoculated plants and

suppressed the other diseases. ShR was high only when alone, with ShB inoculation, or with inoculation of all diseases. It appeared that ShB did not affect ShR development.

negatively correlated with fertile tillers, number of filled grains, and 1,000-grain weight ( r = -0.60*, -0.81**, and -0.58*). Of the four diseases, ShB developed fastest and caused the most damage. Values for yield component characters are in Table 2.

Only ShB was significantly and

Chemical control of ShB in 1984-85 kharif, Pattambi, India.

(%) (0-9)

Disease Disease Treatment Dose/ha incidence severity

Carbendazim 500 g

Carbendazim 500 g

Thiophanate 500 g

Mancozeb 1250 g

50 WP (Bavistin)

50 WP (Jkstein)

70 WP

75 WP

29 (31) 24

(29) 30

(33) 37

(38)

3

2

2

4

Validamycin 1000 ml 13 1

IBP 48 EC 500 ml 34 3 (36)

Check (unsprayed) – 81 9

CD (0.05) (11) 1

3L (21)

(65)

CV (%) 19 21

Influence of sheath blight (ShB) on agronomic traits at different N levels

C. P. D. Rajan, assistant plant pathologist. Agricultural Research Station (ARS), Maruteru, Pin 534122, Andhra Pradesh, India

We studied changes in agronomic traits of MTU6024 caused by ShB at 0, 40, 80,

and 120 kg N/ha. Plant samples from a N level. Plant height, effective tillers per field trial at ARS in 1984 kharif were hill, and number of grains per panicle subjected to split-plot analysis. Main did not differ significantly. Percentage plots were N levels and subplots were filled grains and 1,000-grain weight were healthy and diseased plants. Rice was significantly less in diseased than in planted in 3- × 5-m plots at 20- × 15cm healthy plants (see table). Although spacing and 13 kg P/ha was applied. disease score increased with N, there

diseased plants were recorded. agronomic or yield characters. ShB increased significantly with each

Agronomic traits of healthy and were no consistent changes in

Effect of ShB on agronomic traits of rice in Maruteru, India.

N level

(kg/ha)

Disease Plant height (cm) Effective tillers/hill Grains/panicle (no.) Filled grains (%) 1,000-grain weight (g)

score a Healthy Diseased Healthy Diseased Healthy Diseased Healthy Diseased Healthy Diseased

0 5 99 99 8 8 119 126 86 73 23 23 40 6 100 101 9 9 116 114 87 68 23 22 80 7 102 103 9 9 125 125 88 82 23 23

120 7 104 105 9 9 131 117 88 13 24 23 Mean 6 101 102 9 9 123 120 87 74 24 22

CD H × D 7.2 0.7

CV % 1.2 1.0 3 .0 18.3 11.6 4.1

N 0.5

(0.05)

a Standard evaluation system for rice 0–9 scale.

Effect of inoculum age on transmission of rice gall dwarf virus (GDV)

H. Jumanto, Bogor Research Institute for Food Crops, Jl. Cimanggu Kecil No. 2, Bogor, Indonesia: and T. Omura, T. Usugi, and T. Tsuchizaki, National Agriculture Research Centre, Tsukuba Science City, Ibaraki 305, Japan

Table 1. Transmission efficiency of GDV and RDV from plants of different inoculum ages, Ibaraki, Japan.

Infected plants (no.)

0.5 yr 1.0 yr 2.0 yr Virus Replication Inoculated

plants (no.) 0 yr

GDV I 50 13 7 8 12 II 60 31 – 5 9

RDV I 50 8 2 0 0 60 6 – 0 0

GDV-infected TN1 plants were maintained by vegetative propagation through bimonthly cutting, dividing, and transplanting in an airconditioned greenhouse (27 + 3º C).

(RDV), the transmissibility of which is high for 2 yr. RDV transmissibility reported to decrease very quickly, were decreased very quickly (Table 1). The treated in the same manner and results results indicate that, in favorable were compared with those with GDV. conditions, GDV-infected plants may

GDV transmissibility (Table 1) and provide inoculum for longer than virus concentration (Table 2) remained 2 yr. Inocula of different ages were used for

the transmission test and ELISA. Rice plants infected with rice dwarf virus

Table 2. Detection by ELISA of GDV antigens in rice plants at various times after inoculation, Ibaraki, Japan.

Virus concentration

0 yr 0.5 yr 1.0 yr 3.0 yr Replication Dilution a

I II

1.600 – – – 0.800 3.200 – – 1.600 1.600

a Reciprocal of the highest dilution with positive reaction.

Pest Control and Management OTHER PESTS

Estimating rat damage in deep water rice In Bangladesh, rat damage is estimated

Md. S. Ahmed, Entomology Division, by quadrat sampling, but the method is Bangladesh Rice Research Institute; and not yet reliable for deep water rice. In M. Y. Mian, M. E. Haque, and J. E. Brooks, 1982, we used burrow system density Vertebrate Pest Section, Bangludesh and average amount of stored rice per Agricultural Research Institute, Joydebpur, system to estimate grain loss due to Gazipur, Bangladesh rodents in several deep water areas.


Data on the density of rat burrow systems/ ha were obtained in 7 deep water Upa-zillas (subdistricts) by taking a 30-m-wide transect and crossing 10 to 30 fields from the nearest high ground out to 350 m (see figure). Density within the first 25 m was low because those fields are excavated for repairing highways and to build up island-villages. Burrow system density increased from the 26th m and was almost constant to 175 m, but was low between 176–275 m from high ground. Observations indicated that field condition was more important to burrow density than distance to high ground.

cached rice from burrow systems. Both large and small burrows contained an average 1.7 kg rice (see table).

Damage vanes from Upa-zilla to Upa-zilla. Areas where floods receded first were hardest hit. Low damage and low burrow densities in Rupganj, Polash, and Narshingdhi reflect their low lying nature. Even at harvest the water table was within 0.25 cm of the surface and some fields had 2–5 cm standing water. Under such conditions, bandicoot rats do not invade the fields, but burrow into the shallow bunds separating fields. Damage was thus minimal. Mean density of burrow systems/ ha was 35, mean stored rice was 57.8 kg/ha, and average damage was

At harvest, we collected 23 samples of

Rat damage to deep water rice based upon cached rice in Bangladesh in 1982.

Burrow Estimated a % loss b

Area systems/ stored rice from 1012 ha (kg/ha) kg/ha

Manikganj 76 Manikganj 71 Manikganj 42 Mirjapur 60 Rupganj 18 Rupganj 10 Polash 21 Narshingdhi 20 Daudkandi 27 Daudkandi 11 Gazaria 24 Gazaria 36

Mean 35

126 119 70

100 30 17 35 33 45 19 40 60 58

12 12 7

10 3 2 3 3 4 2 4 6

6

a Based on 1.7 kg/system (mean of 23 samples of cached rice). b Av national yield/ha of 1982- 83 season.


Relation between burrow system density in decp water rice areas and distance from the high ground, Bangladesh, 1982.

5.7% of the crop, although farmers reduced this by collecting cached rice at harvest.

Traditional pest control practices in West Africa

S. A. Raymundo, formerly plant pathologist, UNDP-FAO-IITA-Sierra Leone Rice Research Project, Rice Research Station, Rokupr, Sierra Leone. Present address: International Potato Center, Lima, Peru

Extensive surveys of West African rice farmers, particularly in Sierra Leone, have provided valuable information about pest management practices. Following are some common practices.

Felled tree trunks and other wood remnants are left to help reduce termite damage on rice. When newly cleared fields are completely free of logs, termites feed on rice roots and kill many seedlings.

Before rainy season peaks, soil is mounded so that even when fields are flooded, soil on the mounds remains above water. Weeds emerge and grow. Just before field preparation and transplanting, mounds are broken up and scattered, which kills the weeds. This practice is particularly common in the north, where boliland rice farms are loca ted.

Fields are fenced with palm fronds to prevent rodents from entering. Rodents cause major damage in many rice

Based on 57.8 kg rice/ ha stored by rats, the national loss of deep water rice in 1982 was 89,414 t of paddy.

growing areas in Africa.

more rice varieties is planted in traditional upland rice areas. The mixture of varieties reduces damage by insect pests and diseases and provides stable yields. It is common to see rice fields with a mixture of varieties at varying maturity. Some farmers said this practice makes rice available as needed. Bulk storage encourages destructive storage pests such as rice weevils.

Africa; therefore farmers like awned varieties, which lessen bird damage. Oryza glaberrima and O. sativa indica varieties such as Rok 16 and Ngovie are popular.

In mangrove swamps, farmers plant several rice seedlings per hill to compensate for crab damage. Planting older seedlings also reduces damage.

In a village or town, farmers tend to grow the variety or varieties with similar duration planted at more or less the same time. A variety that matures earlier than others planted nearby will have greater bird damage.

Integrated with other tactics, these simple practices could serve as a basis for effective pest management programs.

In Sierra Leone, a mixture of eight or

Birds are major pests of rice in West

Distance from the high ground (m)

Md. S. Ahmed, Entomology, Division. Bangladesh Rice Research Institute; and M. Y. Mian, M. E. Haque, and J. E. Brooks, Vertebrate Pest Section, Bangladesh Agricultural Research Institute, Joydebpur, Gazipur, Bangladesh

Burrowing pattern of bandicoot rats in deep water rice fields

Map of rat burrow systems, openings, and runways in a deep water rice field in Gazaria, Bangla- desh, at harvest, 1982.

We studied burrowing characteristics of lesser bandicoot rats in a 24- × 45-m deep water rice field in 1982. There were seven burrow systems (see figure), most of which were connected by pathways under the plant canopy. Each system area because burrowing activity depends fumigation may not be efficient in such had 1 to 17 burrow openings, averaging on soil conditions. The study field was a systems, and more time and energy will 7. Burrow length ranged from 1.25 to dry sandy loam, which may encourage be necessary to plug the burrow 27 m and averaged 9.4 m. long burrow systems. Burrow openings for fumigation.

Burrow length may vary by field and

Bandicoot rat damage in deep water rice fields

Md. S. Ahmed, Entomology Division, Bangladesh Rice Research Institute: and M. Y. Mian, M. E. Haque, and J. E. Brooks, Vertebrate Pest Section, Bangladesh Agricultural Research Institute, Joydebpur, Gazipur, Bangladesh

We studied bandicoot rat damage and distribution in deep water rice in 1982 in the Gazaria Upa-zilla of Dhaka district. The 24- × 45-m plot was divided in 1,080 1-m 2 subplots and recently cut stems were counted and recorded for

each subplot. The rat burrow openings and runaways were mapped and locations of cut stems were plotted (Fig. 1).

There were 0 to 38 damaged stems/ m 2 . At harvest, rat damage was greatest near burrow openings and pathways (Fig. 1). More than 30% of the stems were cut within 1 m of burrow openings (Fig. 2). The pattern of damage indicates that field control operations may be more effective if rodenticides and traps are used near burrow openings rather than randomly placed in the field.

2. Relationship of the intensity of rat damage and the distance of burrow openings in a deep water rice field, Gazaria, Bangladesh, 1982.

1. Distribution of rice stems cut by rats during ripening stage in a deep water rice field in Gazaria, Bangladesh, 1982. Each dot represents one cut stem. Burrow openings (open circles) and rat runways (connecting lines) are shown.

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


Soil and Crop Management

Sources and methods of N Grain yield and panicles of rice with different N application methods, Raipur, India. application for drilled, rainfed lowland rice Treatment Panicles/m 2 Grain yield

(no .) (t/ha)

S. R. Patel and B. R. Chandrawanshi, Jawaharlal Nehru Krishi Vishwa Vidyalaya, Zonal Agricultural Research Station, Raipur, Madhya Pradesh, 492012, India

We evaluated sources and methods of N application for rainfed lowland rice on a clay loam soil at Raipur Research Farm (see table). Soil had pH 6.7 and 0.65% organic carbon. Sumridhi (R-2384), a 125-d, gall midge-resistant variety, received 40 kg N/ha in all treatments.

The number of panicles/m 2 was not significantly affected by treatments. However, panicles/m 2 and grain yield were maximum with urea supergranules (USG) placed manually between alternate rows under shallow water after first weeding or 30 d after seeding (DS), followed by urea applied in a single dose

No N (control) Urea broadcast and incorporated as basal dose before seeding Urea applied in plow furrow and seed drilled in alternate rows

USG applied in plow furrow and seed drilled in alternate rows Urea and seed drilled in same furrow

USG and seed drilled in same furrow Urea applied in single dose after first weeding, before land submergence USG placed manually between alternate rows under shallow water, after first weeding

CD (0.05)

after first weeding. Applying N 30 DS was more effective than application at seeding. Applying urea at seeding gave

215

232 1.8 2.0

250 2.0

255 2.2

25 1 25 1

2.1 2.1

258 2.2

267 2.4

ns 0.3

yields equivalent to those of the no N check plot, indicating the magnitude of N loss.

Effect of nursery bed nutrient management and seed treatment on rice grain yield

S. Rajagopalan and S. Palanisamy, Tamil Nadu Agricultural University, Paddy Experiment Station, Ambasamudram, Tamil Nadu, India

We studied the effect of nursery bed nutrient management and seed treatments in a sandy loam soil. Test varieties were TKM9 and IR20. The experiment was in a factorial randomized block with three replications. The treatments are in the table.

Applying diammonium phosphate (DAP) significantly increased rice yield (see table). ZnSO 4 seed treatments produced significantly higher grain yield than other treatments. Seed treatment affected TKM9 more than it did IR20.

Effect of nursery nutrient management and seed treatment on TKM9 and IR20 grain yield, Tamil Nadu. India.

Yield (t/ha)

TKM9 IR20 Nursery nutrient management

No added fertilizer 5.8 3.1 DAP 6.1 4.0

CD 0.4 0.22 Seed treatment

Potassium chloride 1% 5.7 3.6 Manganese sulfate 4% 5.9 3.8 Ferrous sulfate 4% 6.0 3.8 Zinc sulfate 4% 6.4 3.8 Control 5.8 3.8

CD 0.4 ns

Yield response of IR36 and IR42 to N application under nonsubmerged conditions

C. J. S. Momuat, A. Mappe, and I. T. Corpuz, Maros Research Institute for Food Crops (MORIF), Maros, South Sulawesi, Indonesia

We evaluated the yield response of IR36 and IR42 grown under nonsubmerged conditions. Soil was a Ustic Dystropept, sandy clay loam with pH 5.2, 2.78% organic matter, 178 ppm available P (Bray II), and 0.9 meq exchangeable K (NH 4 Ac extract) per 100 g.

Both varieties yielded significantly

Mean grain yield at 14% moisture of IR36 and IR42 as affected by N application, Maros, Indonesia.

Grain yield a (t/ha) Treatment

(kg N/ha) IR36 IR42

0 1.4 d 0.8 d 30 2.9 c 1.7 c 60 4.0 b 2.4 b 90 4.1 b 3.7 a

120 4.9 a 4.2 a 150 4.9 a 4.3 a

CV (%) 11.8 12.6 a Means followed by the same letter are not significantly different at 5% level by Duncan multiple range test.


higher with 30 kg N/ ha than in the no- N check, 60 kg N gave significantly better yields than 30 kg, and 90 kg N

Ratoon crop performance of three rices

B. Basavaraju, B. V. Jayakumar, and M. Mahadevappa. University of Agricultural Sciences, Bangalore 560024, Karnataka, India

Rice in Bangalore, Kolar, and Tumkur Districts of Karnataka, India, often is planted late because irrigation tanks have not filled, and can suffer cold damage. Land often remains fallow until wet season begins in Jun-Jul. We sought to determine the potential of a ratoon crop of rice planted in late wet season.

Mangala, CT1351, and Halubbalu were planted in 3.0- × 1.8-m plots in 4 replications on 15 Aug, 15 Sep, and 15 Oct in late kharif 1983-84. Recommended practices were followed for the main crop, which was somewhat damaged by blast (Bl) and low temperatures. The Bl-damaged plots grew new tillers and produced some grain. The plots were ratooned after main season harvest. The ratoon crop was irrigated 2-3 times a month and was not cultivated or fertilized.

Halubbalu produced no grain in tha main crop because of Bl. Mangala and CT1351 yielded 1.5 to 2.5 t/ha and had moderate B1 resistance. Ratoon yields are in the table. Mangala planted on 15

Ratoon yield of three rice varieties as influenced by three planting dates, Bangalore, India. a

Planting date Variety

15 Aug 15 Sep 15 Oct Mangala GY (t/ha) 1.81 1.41 1.21

MCD (d) 118 126 130 RCD (d) 85 90 80

CT1351 GY (t/ha) 0.94 1.07 1.25 MCD (d) 127 134 140 RCD (d) 100 110 100

Halubbalu GY (t/ha) 0.93 1.49 1.55 (S317) MCD (d) 136 138 148

RCD (d) 105 116 110

RCD = ratoon crop duration.

produced better IR42 yields than 60 Applying 150 kg N did not significantly kg N. IR36 yield at 90 kg N was not increase yield of either variety (see significantly higher than at 60 kg. table).

Aug and ratooned in November yielded ratoon crop are unreliable because there highest followed by Haiubbalu planted was considerable bird damage; however, 15 Oct, and Mangala and Halubbalu they encourage further study of rice planted 15 Sep. Yield data for the ratooning for the area.

Regulating K + and Na + in two rice soil of pH 9.5 and 9.8. Exchangeable

varieties grown in sodic soils sodium percentage (ESP) was 52 and 69. Pots with normal soil (pH 8.1 and ESP

A. Qadar, Division of Genetics and Plant 7) were the control. Soil was 41.4% Physiology, Central Soil Salinity Research sand, 35.0% silt, and 23.2% clay. Cation Institute, Karnal 132001, Harvana, India exchange capacity was 10.6 meq/100g.

Soil had 24, 11, and 85 mg/kg available Rice varieties differ in salt tolerance. NPK. One gram urea and 0.09 g Tolerant varieties generally have ZnSO 4 /pot were applied basally. An comparatively low Na + content per unit additional dose of 0.5 g urea/pot was dry weight with less imbalance in shoot applied at tillering and flowering. K + . The ability to regulate those ions in After 45 d of growth, 3 sets of the top leaves may help prevent Na + excess in 4 fully expanded laminae were sampled young plant parts. Damodar and Jaya. and analyzed for K + and Na + . which have different salt tolerance, were Differences in Na + content were grown under sodic conditions to study statistically significant and were in order their ability to control K + and Na + 1 < 2 < 3 < 4. K + was lowest in the first contents in different laminae and their lamina of control plants. Each lamina of sheaths. Damodar had significantly higher K +

Forty-day-old seedlings were than the corresponding one in Jaya; the transplanted in pots with 8.5 kg sodic reverse was true for Na + (see figure).

Effect of sodicity on K + and Na + contents of different laminae of two rices, Haryana, India. Bars = 1st to 4th laminae K + , vertical lines = Na + .

IRRN 11: 1 (February 1986) 27

a Gy = grain yield, MCD = main crop duration,

Damodar is more salt tolerant than Jaya and regulated Na + and K +f better. For example, at pH 9.8, Damodar had maximum increase of Na + (1600%) in the 4th lamina as compared to Jaya's 1178% over the respective controls.

decreased less than in Jaya. Reduction in the first lamina over the respective controls was 43% for Damodar and 51% for Jaya. Thus, each part of Damodar had lower Na + to K + ratio than that of Jaya .

Analysis 60 d after transplanting showed that each leaf sheath had higher Na + content than its lamina in both genotypes (see table). The same was true for K + ffor the first and second leaf

K + content of each Damodar lamina

Nitrogen use efficiency in relation to seedling age and transplanting time

P.S. Gill and H. N. Shahi, Punjab Agricultural University (PAU), Rice Research Station (RRS), Kapurthala 144601, India

We studied N use efficiency in terms of grain yield and N recovery in relation to seedling age at transplanting at PAU RRS. The 1981 and 1982 trials were in a split-plot design with 3 transplanting dates (30 Jun, 20 Jul, 9 Aug) and 5 N levels (0, 60, 90, 120, and 150 kg N/ ha) as main plots and 3 seedling ages at transplanting (30, 45, and 60 d) as subplots.

puddling. Urea N was applied in equal splits at transplanting, tillering, and panicle initiation. N recovery (kg grain/ kg of applied N) was calculated:

PK was applied at 13-25 kg/ ha at last

Grain yield Grain yield (kg/ha) in – (kg/ha) in

N recovery = N plots 0 N control N level (kg/ ha)

Transplanting 60-d-old seedlings gave highest grain yield (see figure). The differences in grain yield were most significant at later planting dates. Sixty- day-old seedlings outyielded 30 and 45- d-old seedlings with much higher differences under 0 N as well as under all other N levels with a margin of 0.58- 1.1 and 0.184.48 t/ ha.


Effect of sodicity on Na + content of first to fourth laminae (1 L to 4 L ) and their sheaths (1 LS to 4 LS) in two rices (% dry weight), Haryana, India.

Na + content

1 L 2 L 3 L 4 L Mean 1 LS 2 LS 3 LS 4 LS Mean

pH, Variety

8.2 Damodar 0.087 0.070 0.077 0.077 0.078 0.413 0.427 0.473 0.463 0.444 7 Jaya 0.093 0.126 0.123 0.143 0.121 0.303 0.410 0.677 0.917 0.577 9.5 Damodar 0.650 0.760 0.903 1.10 0.854 1.21 1.53 1.86 2.12 1.68

52 Jaya 0.660 0.737 0.977 1.09 0.867 1.45 1.74 1.92 2.37 1.87 Mean 0.373 0.424 0.520 0.605 0.846 1.029 1.232 1.470 CD at 5% S × V × L 0.023 S × V × LS 0.045

sheaths at pH 8.1. At pH 9.5, however, occur because of its poor retranslocation each lamina had higher K + than its from older to younger parts. K +

sheath. In both varieties, sodicity depletion was highest in older plant decreased K + content and increased parts, suggesting that export of K + from Na + . older to younger parts exceeded its

Higher Na + in older laminae seems to import under stress.

Effect of transplanting schedule, N level, and seedling age on rice grain yield, Kapurthala, India.

Recovery increased with N application. Late-transplanted, 60-d Herbicides reduce azolla growth seedlings had much higher N recovery than 30- and 45-d seedlings, although N J. D. Janiya, research assistant, and recovery tended to remain at par for K. Moody, agronomist, Agronomy seedlings transplanted 30 Jun and 20 Department, IRRI Jul.

The increase in grain yield and N When azolla is inoculated in recovery with older seedlings was the net transplanted rice fields to fix N, it also result of balanced dry matter competes with weeds by rapidly production, early flowering, and high covering the water surface. However, it spikelet fertility. does not control all weeds. We studied

ESP

over the control in all treatments except that of K and sawdust. The most fronds survived on rice chaff, which gave the highest single frond weight, followed by cow dung and diammonium phosphate. Rice husk gave the longest root length (see table).

Results showed that soil amendments influence azolla growth and survival in summer. Rice chaff increases moisture holding capacity. Allowing azolla to root may enhance survival over maintaining the fronds in floodwater.

the effect of recommended rates of commonly used rice herbicides (see table) on azolla. The study was in a randomized complete block design with four replications.

Azolla caroliniana Willd. was inoculated at 500 g fresh weight/m 2

immediately after transplanting. Except for oxadiazon applied 3 d before transplanting, all herbicides were applied 4 d after transplanting.

Except for thiobencarb, piperophos - 2, 4-D, and oxadiazon, all herbicides significantly reduced azolla fresh weight by 10 d after treatment. The proprietary mixture of molinate - simetryn - MCPB was most damaging to azolla. Herbicides did not affect azolla N content.

By 20 d after treatment, all herbicides reduced azolla growth. Molinate - simetryn - MCPB killed all azolla. Thiobencarb was least harmful, reducing

Effect of soil amendments on summer growth and survival of Azolla pinnata

K. Nandabalan and S. Kanaiyan, Agricultural Microbiology Department, Tamil Nadu Agricultural University, Coimbatore 641003, Tamil Nadu, India

It is difficult to maintain azolla under field conditions in summer in tropical rice growing areas. We studied the effect of soil amendments on summer azolla growth in Apr 1984.

The experiment was in a randomized block design with 4 replications in 1-m2

plots. The following amendments were added to the plots and mixed thoroughly: 50 kg P/ha, 50 kg K, 500 kg neem cake, 50 kg diammonium phosphate, 10 t rice husk, 5 t fresh cow dung, 10 t rice husk, 10 t rice chaff, 5 t farmyard manure, and 10 t sawdust, Azolla pinnata was inoculated at 400 g/m 2 in 10-cm-deep water. Fronds floated on the water for 2 d and then settled on the soil. Soil was kept saturated for 3 wk.

The number of fronds, biomass/10 cm 2 , single frond weight, and root length were recorded. Biomass increased

Fresh weight and N content of azolla as affected by herbicide application. a IRRI, 1984 wet season.

Herbicide Fresh weight (g/m 2 ) N content (%)

(kg/ha) 10 d 20 d 10 d 20 d Treatment rate

Molinate - simetryn - MCPB Butachlor - 2,4 -D Butachlor

Oxyfluorfen Naproanilide - thiobencarb Pendimethalin Thiobencarb - 2,4-D Piperophos - 2,4-D Oxadiazon Thiobencarb Untreated

2,4-D

0.93 1.25 1.0 0.8 0.14 1.7 0.75 1.2 1 .0 0.75 1.0 –

185 f 223 ef 310 cdef 216 def 310 cdef 348 bcdef 383 bcdef 365 bcdef 485 abcd 438 abcde 612 a 603 a

0 32 fg

g

77 ef 148 ef 238 def 198 defg 160 efg 289 cde 191 defg 489 bc 521 b 135 a

2.5 a – 2.8 a 1.5 a 2.9 a 1.5 a 2.9 a 2.7 a 2.8 a 2.5 a 2.7 a 2.5 a 2.6 a 2.3 a 2.6 a 2.4 a 2.7 a 1.3 a 2.5 a 2.6 a 2.8 a 2.4 a 2.8 a 2.5 a

a Observations were made 10 and 20 d after herbicide application. Means followed by a common letter are not significantly different at the 5% level.

azolla fresh weight 29% compared to the been significant differences in the untreated check. amount of N incorporated because of

effect on azolla N content. However, Weed control measures other than had azolla been incorporated 20 d after herbicides should be used when azolla is herbicide application, there would have grown.

The herbicides had no significant the different fresh weights.

Effect of soil amendments on azolla growth and survival of azolla in summer, Tamil Nadu, India.

Azolla Root Single- Biomass Treatment fronds length frond (g/10 cm 2 )

(no./10 cm 2 ) (cm) wt (mg)

Control Superphosphate Muriate of potash Neem cake Diammonium phosphate Farmyard manure Cow dung Rice husk Rice chaff Sawdust

96 114 107 193 222 88

223 115 311 99

1.4 1.2 1.7 1.8 1.9 1.5 1.3 2.4 1.8 2.1

47.7 49.3 49.7 52.0 62.3 45.7 61.3 64.3 76.3 44.0

14.3 15.3 13.0 20.3 23.7 15.3 22.0 21.7 35.0 12.7

SE : SEd :

4 5

0.1 2.0 0.2

0.6 2.8 0.8

Some physiological studies on rice grown on manganese-deficient soil

N. P. Kaur and V. K. Nayyar, Soils Department, Punjab Agricultural University, Ludhiana 141004, India

Wheat grown in rotation with rice on coarse Punjab soils is showing increasing Mn deficiency, but rice has shown no visual symptoms. To understand this tolerance mechanism, we grew PR103 in a Mn-deficient (DTPA Mn 0.8 mg/kg) loamy sand soil


Table 1. POE and peroxidase activity in chloroplasts (X) and cytoplasm (Y) in rice leaves, 42 d after transplanting, Ludhiana, India. a

Mn applied POE POE Peroxidase Peroxidase (mg/kg) A B X Y

0 9 18 0.60 4.8 2.5 14 28 0.48 4.8 5.0 14 28 0.40 5.4

10.0 15 29 0.38 15 .0

6.4 16 30 0.39 4.7

20 .0 17 32 0.35 4.2

B = OD at 620 nm/100 mg fresh wt per 5 min; a A = OD at 620 nm/unit chlorophyll per 5 min;

roplast; Y = OD at 660 nm/60 s per 100 mg X = OD at 660 nm/60 s per unit enzyme in chlo-

fresh wt in cytoplasm.

in a pot experiment. Four seedlings were transplanted per pot and Mn was applied at 0, 2.5, 5.0, 10.0, 15.0, and 20.0 mg/ kg of soil. Chloroplasts were isolated from leaves 21 and 42 d after transplanting and colorimetrically assayed for photosynthetic oxygen evolution (POE). Peroxidase activity in chloroplasts and cytoplasm was determined colorimetrically using guiacol as substrate. Results at two growth stages were similar. Data for the 42d stage are given here.

Table 2. Elemental composition in rice leaves, yield, and DTPA Mn in soil, Ludhiana, India.

Composition (mg/kg) Yield (g/pot) DTPA Mn applied Mn in soil

(mg/kg) Mn Fe Fe 2+ Zn Grain Straw (mg/kg)

0 53 5 10 174 30 2.4 40 7.7 2.5 71 485 95 32 4.4 42 10.5 5 .0 70 402 100 36 5.9 38 11.8

10.0 115 305 104 34 7.2 39 13.4 15.0 81 278 86 36 7.6 39 15.3 20.0 93 265 83 30 8.4 41 19.3

POE was very low in Mn-deficient application. plants but increased with application of Grain yield was significantly higher 2.5 mg Mn/kg. Applying more Mn did (about 4 times more with 20 mg Mn/kg not proportionately increase POE than with 0 Mn) with Mn application, (Table 1). Chloroplast peroxidase was but straw yield was about the same. highest in plants that received no Mn. Grain filling was incomplete in Mn- Cytoplasmic peroxidase increased up to deficient plants. DTPA Mn content 42 d 10 mg Mn/kg and decreased slightly at after transplanting had increased higher rates. manyfold in all pots due to reduction

Elemental analysis of leaves showed under submerged conditions. Mn concentration increased with Mn Results indicate that although rice supply (Table 2). Fe 2+ and total Fe plants did not show symptoms of Mn content in leaves was highest in 0 Mn deficiency, low Mn decreased plants, indicating an inverse relationship photosynthetic activity and impaired with Mn concentration. Zn translocation of photosynthates to concentration did not change with Mn grain.

The Na-K ratio as index of salt stress in rice cultures

S. Raman, N. D. Desai, J. B. Solanki, and S. M. Bhatt, Water Management Project, Gujarat Agriculture University, Navsari District, India

We screened 16 rices for salt tolerance in coastal soils in South Gujarat.

Grain yield, and K and Na content, and their ratios in different rices, Navsari, India.

Variety (t/ha) (%) (%) Yield K Na Na:K

IET7587 2.6 0.51 1.05 2.06 IET7589 2.9 0.45 1.16 2.58 IET7908 1.8 0.36 1.05 2.92 IET7910 2.5 0.36 0.91 2.53 IET7911 2.3 0.32 0.91 2.84 IET6993 2.1 0.39 1.10 2.82 IET6996 2.6 0.40 1.17 2.92 IET7337 2.8 0.38 1.06 2.79 IET7588 3.4 0.52 0.99 1.90 IET7912 2.1 0.38 0.87 2.29 IR2031-729-2 3.5 0.57 0.68 1.19 SLR51214 2.8 0.40 1.04 2.60

CD at 5% 1.1 0.10 0.20

SLR51214 was the check variety. At transplanting, soil had ECe 9.0 dS/m, pH 8.6, and ESP 25.

Twelve entries performed uniformly and at par with SLR51214. Grains were analyzed for nutrient content and Na:K was calculated (see table). K content varied from 0.32 to 0.57. IR2031-729-2 had highest K and lowest Na and yielded highest. Na:K for most varieties

Azolla as a substitute for N fertilizer in rice cultivation

H. K. Senapati, associate professor, and B. Behera, professor, Department of Soils and Agricultural Chemistry, Orissa University of Agriculture and Technology, Bhubaneswar 751003, Orissa, India

In 1980-81 in Bhubaneswar, we studied azolla as a substitute for N fertilizer in rice cultivation. Soil was a laterite with pH 5.6, CEC 3.5 meq/100 g soil, 0.36% C, 0.35% N, 0.45% P, 1.55% K, 70.1%


was above 2.5. However, IR2031-729-2 had 1.19 and IET7588 had 1.90, indicating a preferential absorption of K over Na.

Yield and K content were highly and positively correlated ( r = 0.96). The relation between yield and Na content was not significant. Na:K, however, was significantly and negatively correlated with yield ( r = –0.82).

sand, 16.3% silt, and 12% clay. The experiment was in a randomized block design with three replications. All plots received 10 cartloads of farmyard manure, 13.3 kg P, and 24.9 kg K/ha before transplanting Pusa 2-21 (IR8/TKM6). Azolla was surface applied or multiplied in situ 1 wk before transplanting. Plots received azolla alone or azolla with urea fertilizer (see table) .

control. Applying 10 t azolla/ ha All treatments yielded more than the

Effect of azolla inoculation on rice yield, Bhubaneswar, India.

Treatment

Yield (t/ha)

1978-79 1979-80 1979-80 Increase kharif kharif rabi (%)

Control 1.7 2.1 3.5 Azolla at 10 t/ha 2.1 3.0 4.6 34 Azolla at 1 t/ha, 1.9 2.6 4.2 20

Azolla at 5 t/ha 2.0 3.0 4.3 30

30 kg N/ha 2.1 3.0 4.6 34 60 kg N/ha 2.3 3.5 4.6 44

–

surface applied

+ 15 kg N/ha

CD 0.4 0.6 0.6

produced the same yield as 30 kg N/ ha. Highest yields were with azolla + urea. Applying azolla increased both total and available N. With 8 azolla crops in 1 season, total N harvest was about 140 kg/ ha at Bhubaneswar and 80 kg] ha in saline conditions.


Effect of phosphorus on kharif rice

S. S. R. Reddy, M. N. Reddy, and P. N. Rao. Agricultural Research Station, Maruteru 534122, Andhra Pradesh, India

We determined the P requirement of kharif rices in 1984 on soil with pH 7.8, EC 0.70 mmho/crn, 0.68% organic carbon, and 12.1 kg available P and 329 kg available K/ha. The experiment was in a split-plot design with three replications. P at 0, 8.7, 17.5, and 26.2 kg/ ha applied basally as superphosphate were main plots; Swarna, Lakshmi, MTU7633, and Vasista were subplots. NK at 40-30 kg/ ha were applied to all treatments.

Swarna yielded highest with an average 5.3 t/ha, which was significantly

Grain and straw yields of 4 rices at 4 P levels, Maruteru, India.

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

0 8.7 kg 17.5 kg 26.2 kg Mean 0 8.7 kg 17.5 kg 26.2 kg Mean

Swarna 5.1 5.2 5.4 5.5 5.3 6.1 5.9 6.2 6.2 6.1 Lakshmi 4.0 3.8 4.1 MTU7633 4.5 5.1

4.3 4.1 5.0 5.0 4.9 5.1 5.0 5.1 5.2 5.0 6.5 6.4

Vasista 4.5 4.8 6.6 6.5 6.5

4.7 5.0 4.7 6.1 6.2 6.9 6.4 6.4 Mean 4.5 4.7 4.8 5.0 4.8 5.9 5.9 6.2 6.0 6.0

CD at 5% P levels Varieties P levels × varieties Varieties × P levels CV%

0.3 0.2 ns ns 4.8

ns 0.2 ns ns 3.7

superior to that of all other varieties. P MTU7633 had the highest mean straw significantly increased yield only at 26.2 yield of 6.5 t/ ha. Swarna performed best kg P/ ha (see table). P levels did not and 8.7 kg P/ha appears to be optimum significantly influence straw yield. and economical for the test varieties.

Storing Azolla pinnata inoculum for transport

D. Sukumar and S. Kannaiyan, Agricultural Microbiology Department, Tamil Nadu Agricultural University, Coimbatore 641003, Tamil Nadu, India

We evaluated different storage techniques for A. pinnata, Coimbatore strain. Fresh A. pinnata fronds were collected from field multiplication plots, soil was washed from their roots, and water was drained from them. The fronds were stored in cotton cloth, polyester cloth, newspaper, brown paper, polythene, polythene-lined gunny, and gunny bags for 5 d. Frond survival was recorded on days 2, 3, 4, and 5. All

Different bags for storing azolla, Coimbatore, India,

Azolla survival (%) Treatment

Recovery (%) in the field

2d 3d 4d 5d when inoculated

Cotton cloth bag 100 58 45 19 100

26 Polyester cloth bag 53 40 17 17 Newspaper bag 100 57 56 19

100 21

Brown paper bag 41 38 16 100

15 Polythene bag 66 65 32

100 46

Polythene-lined gunny bag 62 46 28 Gunny bag 100 61 22 27

27 44

5 5 2 4 CD

azolla lived for 2 d, then began to die. gunny bags performed best (see At 5 d, polythene and polythene-lined table).

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


Announcements Chang honored

T.T. Chang, IRRI principal scientist, recently received the following honors.

He was selected for the Outstanding Achievement Award of the University of Minnesota, which Minnesota President Kenneth Keller describes as “the University’s way of recognizing former students who have attained distinction and honor in their fields.” The award is the highest honor the university gives alumni.

For his activities in germplasm collection and maintenance, Chang received a bronze medal from the

published in Weed Research (14:415-21, 1974). It has been cited in more than 250 publications.

International Board for Plant Genetic Resources.

A paper coauthored by Chang with J.C. Zadoks and C.F. Konzak was included in “This Week’s Citation Classic” in the 14 Oct 1985 Current Contents. The paper, “A decimal code for the growth stages of cereals.” was

Yuan Longping receives World Intellectual Property Organization (WIPO) gold medal

Yuan Longping, director of the Hybrid Rice Research Institute, Hunan Academy of Agricultural Sciences, recently received the WIPO Invention and Creation Gold Medal. The award is the highest honor ever given for scientific research in China.

tonnes. Yuan is deputy chairman of the

Chinese Crop Science Association and a member of the Scientific Board of the Ministry of Agriculture. He was a member of the China People’s Congress from 1978 to 1983.

New IRRI publications

The following new IRRI publications are available for purchase from the Communication and Publications Department, Division R, IRRI, P.O. Box 933. Manila. Philippines:

Yuan pioneered the development of commercial F l hybrid rice in China in 1974. Through his persistent efforts and dynamic leadership, China now grows about 8 million ha (22% of total rice area) of hybrid rice each year. Planting hybrid rice has increased China’s annual rice production by about 6 million

Women in rice farming Flowering response of the rice plant to

photoperiod, rev. ed., by B.S. Vergara and T.T. Chang, 1985

Rice diseases, 26 ed., by S.H. Ou.

ISSN 0115-0944

The International Rice Research Institute P.O. Box 933, Manila, Philippines

international rice research newsletter vol.11 no.1

Documents