international rice research notes vol.22 no.3

International Rice Research Notes The International Rice Research Notes (IRRN) expedites communication among scientists concerned with the development of improved technology for rice and rice- based systems.

other informed of current rice research findings. The concise scientific notes are meant to encourage rice scientists to communicate with one another to obtain details on the research reported.

The IRRN is published three times a year in April, August, and December by the International Rice Research Institute.

The IRRN is a mechanism to help scientists keep each

• • • • • • • • • • • • • •

IRRN production team

Editors: Carolyn Dedolph, Domenic Fuccillo, Bill Hardy Assistant editor: Teresita Rola Layout and design: Erlie Putungan Artwork: Erlie Putungan

Contents Vol. 22, No. 3, 1997

Genetic resources Diversity of leaf epidermal structures used in biosystematics of rice

species 4

Genetics Heterosis for physicochemical characters in rice 5 Variability and heritability estimates of yield and yield components in

some Nigerian lowland rice genotypes 6 Analysis of genetic and genotype × environment interaction effects

on heterosis of nutrient quality traits in indica hybrid rice 7 Genetic diversity among upland rice varieties from India and

Bangladesh 8

Breeding methods Performance of exotic (IRRI) and locally developed cytoplasmic male

Comparison of regeneration frequency of green plantlets from in vitro

Determination of suitable time to select trisomics induced from

sterile lines at Kapurthala, Punjab, India 9

culture of young panicles of wild rice 10

anther culture of autotetraploid rice 11

Grain quality Multisample rice cooker for evaluating eating quality 12 Njavara: a unique rice race of the humid tropics 12

Pest resistance New rice breeding lines with multiple pest resistance 13

Pest resistance—diseases Cross-fertility and pathogenicity of the blast fungus Magnaporthe

Performance of midland rice varieties in a blast hot spot 15

Stress tolerance—drought Effect of water deficit on plant water status, growth, and

grisea Sac. isolated from cultivated and wild rice in Yunnan 14

yield of rice 16

Stress tolerance—adverse temperature Mass screening and identification of rice germplasm tolerant of light

and temperature stress 17

Stress tolerance—adverse soils Variation in salt tolerance among rice mutants and varieties based

Water relations in rice seedlings in saline medium 19 on yield attributes 18

Germplasm improvement

2 IRRN 1997

Integrated germplasm improvement—irrigated Te-Shan-Ai No. 2, a high-yielding rice in China 20 Cilosari: a new rice variety released in Indonesia through cross

hybridization of the mutant line with IR36 21 FARO 44 and FARO 50: two irrigated lowland rice varieties for

Nigeria 21 Xingxiangyou 77, a high-yielding and fine-quality quasi-aromatic

hybrid rice 22

Integrated germplasm improvement—rainfed lowland New rice varieties for the rainfed lowlands of Cambodia 23

Integrated germplasm improvement—upland FARO 45 to FARO 49: two early-maturing and three medium-

maturing upland rice varieties released in Nigeria 24

Integrated germplasm improvement—flood-prone Saraswati and Jalaprabha: two new deepwater rice varieties for

eastern India 25

Integrated pest management—diseases Two Myanma isolates of rice tungro bacilliform virus belong to the

Hinosan (0.05%): an ecofriendly fungicide for managing rice sheath Southeast Asian strain 31

blight 32

lntegrated pest management—insects Record of Aspergillus terreus Thom. on rice grasshopper

Hieroglyphus banian (F.) in India 33

Integrated pest management—weeds Weed control practices for improving N use efficiency and productiv-

ity of flood-prone lowland rice 34

Water management On-farm water management studies in ricefields of north Bihar,

India 35

On-farm water management studies in summer rice 36

Seed technology Nucleus and breeder seed production of thermosensitive genic

male sterile lines 26 Use of the chlorophyll meter in N management of subtropical wheat - following rice 37

Fertilizer management—inorganic sources Response of promising rice genotypes to N levels in rainfed

lowlands 27 1998 Calendar of International Training Courses 38

Fertilizer management—organic sources Performance of Azolla hybrids in lowland rice culture 28 Influence of sowing time on biomass production and seed yield

Vermicompost: a potential supplement to nitrogenous fertilizer of three green manure crops 29

in rice nutrition 30

Research methodology

Announcement

Crop and resource management

Vol. 22. No. 3 3

page 4

page 18

Germplasm improvement

Diversity of leaf epidermal structures used in biosystematics of rice species

Z. Y. Zhang, Laboratory of Systematic and Evolutionary Botany (LSEB), Institute of Botany, Chinese Academy of Sciences (CAS), Beijing 100093, and Zhongshan University, Guangzhou 510275, China; J. Wen, LSEB, CAS; and B. R. Lu, IRRI

The rice genus contains 24 annual or perennial species, including two cultivated rice species, i.e., the Asian rice ( Oryza sativa L.) and African rice ( O. glaberrima Steud), and 22 wild species in the tropics.

of the leaf epidermis of 22 rice species (see table) were observed by light microscopy to find characters for

In this study, morphological features

identifying species and to assess systematic relationships in the genus. For example, O. schlechteri, O. ridleyi,

O. brachyantha, O. officinalis, O. minuta, O. sativa, O. nivara, and O. meyeriana have elliptic stomatal complexes, whereas in other species they are rhombic. The size of papillae on most epidermal surfaces ranged from small (1.5-4.4 µm diam) to medium (9-18 µm) to large (21-30 µm), and their size and distribution were very useful in identifying species. In addition, the number and location of the small papillae in stomatal complexes differed between species.

Based on the following combinations of leaf epidermal characters, i.e., the size and distribution of papillae on the abaxial surface of the epidermis, the

O. longiglumis, O. granulata,

International Rice Genebank Collection (IRGC) number, chromosome number, genomic group, and distribution of rice species used in the experiment. Beijing, China.

Species IRGC accession no. Chromosome number Genome Country of origin 2n =

O. barthii A. Chev. 103908 24 AA Tanzania O. glumaepatula Steud. 105465 24 AA Guiana O. longistaminata Chev. et Roehr. 101221 24 AA Mali O. rneridionalis Ng 101147 24 AA Tropical Australia O. nivara Sharma et Shastry 102163 24 AA Taiwan

O. rufipogon Griff. 105567 24 AA lndonesia O. sativa L. 36865 24 AA China O. punctata Kotechy ex Steud. 104975 24 BB Kenya O. eichingeri Peter 101424 24 CC Uganda

Uganda Uganda

O. officinalis Wall ex Watt 100176 24 CC Thailand

O. rhizornatis Vaughan 105448 24 CC Sri Lanka O. minuta J. S. Presl. et C. B. 103879 48 BBCC Philippines

O. alta Swallen 101395 48 CCDD Mexico O. grandiglumis (Doell) Prod. 106241 48 CCDD Brazil O. latifolia Desv. 100962 48 CCDD Guatemala O. australiensis Domin. 10370 24 EE Tropical Australia O. granulata Nees et Arn ex Wall. 106468 24 GG Lao PDR O. meyeriana (Roll. et Mor. ex 104990 24 GG Malaysia

O. longiglumis Jansen 105562 48 JJHH Indonesia O. rldleyi Hook f. 105973 48 JJHH lndonesia

O. brachyantha Chev. et Roehr. 105172 24 FF Cameroon O. schlechteri Pilger PNG 1 b 48 ?? Papua New Guinea

a This tetraploid taxon was described as Oryza malampuzhaensis Krish. et Chand., but its morphological features are very similar to those of O. officinalis. Following the treatment of Vaughan (1989), it is included in O. officinalis. b Field collection number.

100593

105182 105163

100957 (4x) 48 a India

Presl.

Steud.) Baill

100877 Thailand

number and location of the small papillae in stomatal complexes, and the shapes of stomatal complexes, the 22 studied Oryza species could be divided into three main groups.

In the first group, which included O. longiglumis, O. ridleyi, O. meyeriana, and O. granulata, neither large- nor medium-sized papillae (in some cases, extremely rare small papillae) were found on the surfaces of epidermis and no small papillae were found in stomatal complexes. All species in this group had elliptic stomatal complexes (Fig. 1). This group included species classified in O. meyeriana and O. ridleyi complexes based on external morphological characters.

O. brachyantha, diploid and tetraploid O. officinalis,O.minuta, O. eichingeri, O. punctata, O. latifolia, O. alta, O. grandiglumis, O. rhizomatis, and O. australiensis. In these species, usually no large papillae were observed, but medium-sized and densely populated small papillae were found to cover the surfaces of epidermis, and at least four small papillae were found in stomatal complexes (in guard cells) of most species. This group contains all species in the O. officinalis complex.

The second group included

1. Abaxial leaf epidermis of O. ridleyi (x1120), showing no papillae on the surface of the epidermis, and elliptic stomatal complexes without papillae.

Genetic resources

4 IRRN 1997

2. Abaxial leaf epidermis of O. nivara (x1 120), showing small and medium-sized papillae on the surface of epidermis, and rhombic stomatal complexes with 6-8 small papillae in subsidiary cells (indicated by arrows).

The third group included O. sativa, O. nivara, O. rufipogon, O. longistami-

O. barthii, and O. schlechteri. The abaxial leaf epidermis of these species was usually covered with large, medium- sized, and small papillae. In addition, more than four (usually 6-8) small papillae were found in guard cells or subsidiary cells of the stomatal complexes (Fig. 2). Most species in the second and third groups had rhombic stomatal complexes. This group is correlated to the morphologic O. sativa complex, except for O. schlechteri, which does not belong to any of the morphologic complexes.

These results largely agree with previous biosystematic studies of rice species that apply other methodologies, i.e., species within complexes have rather close relationships whereas those between complexes have a comparatively distant relationship. These results also show that leaf epidermal characters provide additional information for species identification in Oryza.

nata, O. lumaepatula, O. meridionalis,

Heterosis for physicochemical characters in rice

S. Geetha and A. Ayyamperumal, Sugarcane Research Station, Sirugamani 639115, Tamil Nadu, India

Reports on heterosis for the physicochemical grain quality characters in rice are limited. We studied the heterotic manifestations in nine grain quality characters in 30 hybrids involving six

Duansan, TKM6, and ADT39. The hybrids were created by full diallel mating of these six parents.

The experiment was laid out in a randomized block design with three replications during the 1993-94 dry

parentts—IR50, ADT37, ADT41,

season. Each genotype (parents and hybrids) was planted in three 3-m rows at 30- × 20-cm spacing. Observations were recorded for five randomly selected plants per replication.

Seeds were dehulled in a McGill sample sheller and milled in a Kett rice polisher. Cooking characters were measured as suggested by Juliano and Perez (1984). Amylose content was measured by the method of Juliano (1971), and the protein per grain was estimated by the method of Shenoy et al (1994).

The performance of hybrids over mid-parent (relative heterosis) and over the better parent (heterobeltiosis) was estimated following standard procedure (see table). The heterosis for

Summary of heterosis on nine physicochemical characters in hybrid rice.

Relative heterosis Heterobeltiosis Top-ranking

Character Range Significant Range Significant hybrids crosses a crosses a

(no.) (no.)

Kernel length -7.98 to 25.36 15 -18.60 to 19.65 8 ADT41/IR50 ADT39/ADT37 TKM6/ADT39 TKM6/ADT37

Kernel breadth -40.63 to 18.06 15 -44.84 to 15.12 9 TKM6/ADT39 ADT41/IR50

Kernel L-B ratio -12.68 to 68.27 10 -32.61 to 58.32 6 –

Kernel length -21.34 to 26.43 14 -23.48 to 41.36 6 Duansan/ADT39 after cooklng IR50/ADT37

ADT41/IR50

Kernel breadth -9.26 to 31.89 14 -31.79 to 30.64 15 Duansan/ADT39 after cooking

ADT41/IR50 Duansan/lR50

Linear elongation -27.38 to 41.69 12 -37.79 to 33.82 11 ADT39/ADT41 IR50/Duansan ADT41/IR50

Elongation index -55.84 to 59.74 13 -55.84 to 59.74 9 Duansan/ADT39 Duansan/ADT41 ADT41/IR50

Amylose (%) -44.71 to 56.62 22 -44.78 to 42.60 19 ADT39/ADT37 TKM6/Duansan

Protein grain -1 -29.03 to 41.59 12 -42.11 to 32.69 7 ADT37/IR50 ADT39/Duansan ADT41/IR50

a Significant in the desirable direction.

Genetics

Vol. 22, No. 3. 5

the characters studied was consider- ably high and indicated the possibility of exploiting hybrid vigor for these traits. Among these hybrids, cross ADT41/ IR50 showed desirable heterobeltiosis for seven out of the nine

characters studied. The heterobeltiosis for this hybrid for kernel length was 1.23; kernel breadth, 5.70; kernel length-breadth ratio, 7.13; kernel length after cooking, -13.90; linear elongation, 8.70; elongation index, 22.97; amylose

content, 13.6; and protein per grain, 2.44. Duansan/ADT39 was promising for kernel length after cooking, kernel breadth after cooking, and elongation index.

Variability and heritability estimates of yield and yield components in some Nigerian lowland rice genotypes

T. Vange and A. A. Ojo, Crop Production Department, University of Agriculture, PMB 2373, Makurdi, Nigeria

The essential aspects of most, if not all, breeding programs can be divided into three stages: assembly or creation of a pool of variable germplasm, selection of superior individuals from the pool, and use of selected material for creating new populations to be employed as either potential commercial varieties or the base for a new cycle of selection. Estimates of genetic variance and

heritabilities can be of value in all three stages.

We studied 10 early-duration and 12 medium-duration rice genotypes during the 1994-95 cropping season (Jul-Nov) at the University Experi- mental Research Station (UERS) to select promising genotypes. The experiment was laid out using a randomized complete block design with 4- × 3-m plots and three replicates for the medium-duration genotypes and four for the early-duration genotypes.

randomly selected plants per replication. Mean (X), standard deviation (SD), phenotypic coefficient of variability (PCV) and genotypic

Observations were recorded on five

Genetic parameters for 12 traits in selected lowland rice genotypes. University of Agriculture, Makurdi, Nigeria, 1994-95.

Trait Mean Standard Genotypic Phenotypic Broad sense Genetic

(X) deviation coefficient of coefficient of heritability advance variation variation (h 2 ) as % of mean

Medium duration 50% heading (d) Plant height (cm) Tillers m -2 (no.) Panicles m -2 (no.) Panicle length (cm) Branches panicle -1 (no.) Panicle weight (g) Seeds panicle -1 (no.) Seed weight panicle -1 (g) 1000 weight (g) Dry biomass yield (t ha -1 ) Seed yield (t ha -1 )

Early duration 50% heading (d) Plant height (cm) Tillers m -2 (no.) Panicles m -2 (no.) Panicle length (cm) Branches panicle -1 (no.) Panicle weight (g) Seeds panicle -1 (no.) Seed weight panicle -1 (g) 1000 seed weight (g) Dry biomass yield (t ha -1 ) Seed yield (t ha -1 )

87.5 78.8

207.7 188.3

24.5 10.4

4.0 142.2

3.43 25.8

5.21 3.85

79.60 73.40

205.88 173.80

23.79 9.36 3.10

127.40 2.89

25.69 4.00 3.00

10.80 70.64 8.15 65.68

28.00 1376.46 33.80 322.02

1.04 1.24 1.04 0.24 0.50 0.17

19.30 127.27 0.76 0.44 2.85 9.95 0.97 2.46 0.96 0.76

10.06 91.18 11.91 74.64 24.77 52.00 14.73 42.00

6.94 43.00 7.81 36.00

16.77 37.78 17.13 21.00 30.58 40.00 13.35 83.00 43.05 49.00 37.00 37.00

18.92 18.33 26.57 12.76

6.16 5.80

13.07 7.42

13.30 22.87 43.52 28.32

4.03 5.21 5.88 78.50 9.58 6.22 8.25 10.68 59.61 13.11

39.20 12.64 18.96 44.43 17.36 25.55 10.53 19.13 30.31 11.94

1.10 3.12 8.00 15.19 2.50 1.18 12.80 15.46 68.50 21.82 0.59 15.04 43.49 11.97 10.72

17.26 10.95 21.61 25.68 11.43 0.61 19.11 30.62 38.95 24.57 2.30 8.75 10.76 66.16 14.66 0.78 18.33 24.97 53.89 27.71 0.78 30.14 39.69 57.67 47.15

coefficient of variability (GCV), broad- sense heritability (h 2 ), and genetic advance as percentage of mean (GA%) were calculated for 12 traits (see table).

Considerable differences were observed for all the traits in both medium- and early-duration rice genotypes, indicating wide variability and room for improvement through selection. The PCV was generally higher than the GCV in both early- and medium-duration genotypes The differences were low for days to 50%, heading, however, and plant height in the medium-duration rice group and panicle weight, panicle length, and seed weight panicle -1 in the early- duration group.

A moderate amount of variability (10-20%) was observed for days to 50% heading, plant height, panicles m -2 , panicle weight, number of seeds panicle -1 , and 1000-seed weight in the medium-duration category, whereas in the early-duration category plant height, tillers m -2 , panicles m -2 , branches m -2 , seed weight panicle - 1 , and 1000- seed weight showed a moderate amount of variability.

The medium-duration rice genotypes had very low GCV for panicle length and branches panicle -1 , whereas the early- duration rice had very low GCV for days to 50% heading and panicle length. High h 2 as well as high GA%, for the medium- duration group was observed for days to 50%) heading, plant height, 1000-seed weight, and tillers m -2 . Dry biological yield and seed yield had high GA% while in the early-duration genotypes, seed weight panicle -1 , dry biological yield, and seed yield had high h 2 and GA%. High h 2 coupled with high GA% indicates a predominance of additive gene effects.

6 IRRN 1997

Analysis of genetic and genotype × environment interaction effects on heterosis of nutrient quality traits in indica hybrid rice

Chunhai Shi and Jun Zhu, Agronomy Depart- ment Zhejiang Agricultural University (ZAU); Yonggui Yu, Xiaoe Yang, and Jianming Xue, Soil Science and Agricultural Chemistry, ZAU, Hangzhou 310029, China

Nine cytoplasmic male sterile (CMS) lines and five restorer lines of indica rice were used in an incomplete diallel cross (9 × 5) for 2 yr. The CMS lines were Zhexie 2 A, Xieqingzao A, Zhenan 3 A, Gangchao 1 A, Yinchai 1 A, Erjiuqing A, V20A, Zuo 5 A, and Zhenshan 97 A and the five restoring lines were T49, Cezao 2-2, 26715, 102, and 1391. They were randomly sampled from a reference population. Seedlings of parents and F 1 s with three replications were planted in the field experimental farm at ZAU. Seeds were sown on 28 Mar 1994 and 3 Apr 1995, and single plants of 31-d-old seedlings were transplanted at 20- × 20- cm spacing, 24 plants in each plot. Seed samples of parents and F 1 and F 2 plants were derived at maturity from eight

The F 1 seeds which were harvested plants in the middle part of the plot.

crossing CMS lines to restorer lines at from female parents were obtained by

flowering. Quantitative traits of rice nutrient quality (see table) were

each sample of parents, F 1 s, and F 2 s. measured with three replications for

traits for F 2 over the mean of parents The components of heterosis of seed

were predicted for various types of heterosis (see table). We found that nutrient quality of milled rice from these hybrids was influenced by seed, cytoplasmic, and maternal heteroses (see table). Interaction was larger than genetic heteroses, and was associated with increased nutrient quality traits in

heterosis was larger in 1994 than in 1994 but not in 1995; similarly total

1995. Maternal heterosis (-0.04) and

Mean (range) of heteroses for nutrient quality traits of F 2 seed in indica hybrid rice. Hangzhou, China, 1994-95.

Parameter Genetic heterosis Interaction heterosis Interaction heterosis in 1994 in 1995

Protein content

Cytoplasmic heterosis Direct heterosis

Material heterosis

Protein index


Maternal heterosis

Lysine content


Maternal heterosis

Lysine index


Maternal heterosis

–0.03 (–0.09 ~ 0.04) 0.02 (–0.02 ~ 0.05)

–0.04 (–0.21 ~ 0.11)

0.01 (–0.02 ~ 0.04) 0.02 (–0.07 ~ 0.13) 0.00 (–0.09 ~ 0.15)

0.02 (–0.07 ~ 0.15) na

–0.01 (–0.12 ~ 0.09)

0.02 (–0.14 ~ 0.19)

0.01 (–0.22 ~ 0.21) na

cytoplasmic heterosis (0.02) were the main components in genetic heterosis for protein content (PC) and protein

heterosisin 1994, direct interaction index (PI), respectively. For interaction

heteroses were larger for PC, PI, and lysine content (LC) traits, but cytoplasmic interaction heterosis was larger for the lysine index (LI) trait. Other- wise, interaction heterosis in 1995 mainly came from cytoplasmic

0.17 (–0.03 ~ 0.36)

–0.01 (–0.27 ~ 0.21) 0.04 (–0.07 ~ 0.15)

0.13 (–0.00 ~ 0.38) 0.10 (–0.06 ~ 0.27) 0.06 (–0.25 ~ 0.39)

0.16 (–0.12 ~ 0.75) 0.13 (–0.11 ~ 0.39) 0.11 (–0.45 ~ 0.83)

0.11 (–0.15 ~ 0.66) 0.19 (–0.08 ~ 0.58) 0.18 (–0.41 ~ 0.96)

–0.06 (–0.21 ~ 0.13) –0.08 (–0.16 ~ 0.04) –0.08 (–0.36 ~ 0.14)

–0.05 (–0.22 ~ 0.15) –0.07 (–0.19 ~ –0.01) –0.06 (–0.35 ~ 0.13)

–0.08 (–0.50 ~ 0.28) –0.16 (–0.39 ~ 0.04) –0.17 (–0.76 ~ 0.60)

–0.14 (–0.38 ~ 0.14) –0.06 (–0.46 ~ 0.33)

–0.13 (–0.79 ~ 0.60)

heterosis for PI and LI, maternal and cytoplasmic interaction heterosis for PC, and maternal interaction heterosis for LC. Crosses such as V20 A/26715, which had significant genetic and interaction heteroses in 1994, could increase PC and PI. Crosses such as Yinchao 1 A/T49 and Zhexie 2 A/ 26715, which had significant genetic interaction heteroses in 1994, could increase LC and LI, respectively.

Vol. 22, No. 3 7

H=[F 2 – P 1 + P 2 ]/µ 2

Genetic diversity among upland from India and Bangladesh (see table), rice varieties from India and

tions between indica and aus types in We analyzed 64 upland rice varieties

Bangladesh their selection programs. The aus group

traditional and improved, for their soil conditions prevailing in the upland isozyme variation at 14 loci— Adh1, brings good adaptation to the aerobic

B. Courtois, IRRI/Centre de coop ration internationale en recherche agronomique pour le developpement, departement des cultures annuelles; P. K. Sinha, K. Prasad, Central Rainfed Upland Rice Research Station, Hazaribagh, India; and S. Carandang, IRRI

Isozyme analysis is a simple and powerful tool to examine genetic diversity of rice varieties for neutral markers. Rice germplasm was classified into six groups based on allelic associations across 15 isozyme loci. Understanding the pattern of variation existing among varieties grown in a given ecosystem is important for breeders and could help to optimize the choice of parents for hybridization.

Amp1, Amp2, Amp3, Amp4, Cat1, Est1, Est2, Est5, Est9, Icd1, Pgi1, Pgi2, and Sdh1. For each variety, we analyzed 10 coleoptiles that allowed us to assess within-sample diversity.

Five among the 14 tested loci were monomorphic ( Amp4, Est5, Icd1, Adh1, Cat1 ). The 64 varieties were classified using an algorithm based on the alleles present at 5 loci ( Pgi1, Pgi2, Amp3, Amp2, Amp1 ). Thirty-five belonged to the indica group (mostly improved varieties) and 22 belonged to the aus group (partly traditional, partly improved varieties) as defined in the classification established by Glasz- mann (1987). This grouping reflects the strategy developed by Indian upland rice breeders who favor recombina-

Classification of upland rice varieties from India and Bangladesh into isozyme groups. a

ecosystem, whereas the indica group is used for its yield potential.

Several samples, notably among the traditional varieties, were mixtures of different types for one or several loci. This phenomenon is frequently encountered in traditional varieties and can be observed even in varieties that are phenotypically homogeneous, but induces some difficulties in the classification, notably when the samples are mixtures for the classifying loci. Five varieties could not be assigned to a varietal group (noted with “?” in the table).

The classification in groups is meaningful mostly for the traditional varieties. Because of the recombina- tions occurring in improved varieties,

Variety Type Country Isozyme Within-sample Variety Type Country Isozyme Within-sample of origin group b diversity c of origin group b diversity c

Akashi IMP IND 1 M (3) Rasi IMP IND 1 H Annada IMP IND 1 M (2) RP2220-111-84-20 IMP IND 1 H Aus196 TRAD BGD 2 M (1) RP2235-35-40-5 IMP IND 1 H Aus257 TRAD BGD 2 M (2) RR13-51 IMP IND 1* H Aus454 TRAD BGD 2 M (1) RR137-83-5 IMP IND 2 H Bala IMP IND 1 M (1) RR139-1 IMP IND 1 H Birsadhan 101 IMP IND 1 M (2) RR149-177 IMP IND 1 H Blrsadhan 102 IMP IND 2 H RR151-3 IMP IND 1 H Black Gora TRAD IND ? M (4) RR151-85 IMP IND 2 H BR20 IMP BGD 1 M (2) RR151-91 IMP IND 2 M (1) BR4290-3-3-5 IMP BGD 1+6 H RR159-90 IMP IND 2 M (1) Brown Gora TRAD IND 2 M (2) RR165-1160 IMP IND 1 M (1) Cauvery IMP IND 1 H RR166-645 IMP IND 1 H CH45 TRAD IND 1 H RR167-982 IMP IND 1* M (1) Charka Gora TRAD IND 2 M (1) RR174-1 IMP IND 2 M (1) CO 13 IMP IND 1+6 H RR180-1 IMP IND 1* H CR143-2-2 IMP IND 2 M (1) RR19-2 IMP IND 1* M (1) Dehula TRAD IND ? M (7) RR2-6 IMP IND 1* M (1) Dular TRAD IND 2 M (1) RR20-5 IMP IND 2 M (2) Dumai TRAD IND 1* H RR227-8 IMP IND 1 M (1) Hira IMP IND 1 H RR235-64 IMP IND 1* M (1) Jonga TRAD IND 2 H RR50-128 IMP IND 1 H Kalakeri TRAD IND 2 H RR50-3 IMP IND 1 M (1) Kalinga III IMP IND 1 M (1) RR51-1 IMP IND 1 H Kalyani 2 IMP IND 1 H RR6-1 IMP IND 2 M (2) Karhni TRAD IND 2 M (1) Saita TRAD IND 2 M (4) Lalnakanda 41 TRAD IND 2 H Sattari IMP IND ? M (6) Laloo 14 TRAD IND 1 H Sathi 34-36 TRAD IND ? M (7) N22 TRAD IND 2 H Surjamukhi TRAD IND 2 H Nagpur 26 TRAD IND 1 H Vanapraba IMP IND 1 H

Neela IMP IND 1 M (1) Vandana IMP IND 1 H Prasanna IMP IND 1 H VHC 1253 TRAD IND ? M (4)

a TRAD = traditional variety, IMP = improved variety (includes selection from or mutant of a traditional variety); IND = India; BGD = Bangladesh, H = homogeneous sample; M = mixture of types. b 1 = indica; 1* = close to indica; 2 = aus; 1+6 = recombinatlon of indica and japonica alleles, ? = unclassified. c Number in parentheses indicates the number of loci with several alleles. The classification of varietal groups is based on the most frequent allele.

8 IRRN 1997

some samples presented an allelic clear-cut differentiation into two combination that did not allow a clear- (see figure). This tree shows the same

maximize potential genetic progress. similarity based on Euclidean distances on the basis of their genetic distance to excluded) according to their genetic a tool to help breeders choose parents of the varieties (Sattari and Sathi 34-36 group. The dendrogram can be used as established a dendrogram clustering 62 appears less diverse than the indica variation at the polymorphic loci, we two varietal groups. The aus group 3-5 assigned to group 1+6). From allelic groups corresponding roughly to the cut classification (CO 13 and BR4290-3-

Performance of exotic (IRRI) and locally developed cytoplasmic male sterile lines at Kapurthala, Punjab, India

R. K. Gautam, T. S. Bharaj, Om Vir, H. S. Muker, H. S. Randhawa, and R. S. Sekhon, Punjab Agricultural University (PAU), Regional Rice Research Station (RRRS), Kapurthala, Punjab 144601, India

Stability of a cytoplasmic male sterile (CMS) line is of the utmost importance for hybrid rice to be commercially useful. In this study, 20 IRRI CMS lines (IR66707A carrying Oryza perennis cytoplasm and all others carrying wild abortive [WA] cytoplasm imparting male sterility) and 13 locally developed CMS lines (all WA-derived) were evaluated for male sterility, days to 50% flowering, plant height, anther color, and grain type at PAU in Kapurthala during the 1996 kharif (wet season). The seeds of CMS lines were produced by hand pollination on a paired plant basis. Each CMS line was planted in paired rows of 12 plants. Spacing between rows and among plants was 20 cm. During flowering, anthers of 5- 10 spikelets from two tillers of each plant were squashed and pollen grains were stained with 1% IKI solution and observations for sterile (unstained) pollens were made from five or six microscopic fields. Two panicles of each plant were also bagged before anthesis to study their spikelet fertility at maturity. Based on the degree of male sterility, a CMS line was termed as completely sterile, highly sterile, sterile, partially sterile, or partially fertile.

Of the locally developed CMS lines, Pb CMS 1A, 2A, 3A, 4A, 8A, 10A, 11A, 12A, and 13A were completely sterile; 7A, highly sterile; and 5A, 6A, and 9A, partially sterile. Among the IRRI-bred CMS lines, 11 were completely sterile, three highly sterile, and the remaining six partially sterile to partially fertile (see table).

Breeding methods

Vol. 22, No. 3 9

Pollen/spikelet sterility scores and other features of local and IRRI CMS lines at Kapurthala.

Sterility reaction a Days to Plant height (cm) Anther color Grain flowering and shape type b CMS line

Pollen Spikelet A line B line Percent reduction

Pb CMS 1A CS CS 110 PB CMS 2A

83 102 18.6 Yellowish CS

LS CS

Pb CMS 3A 110

CS CS 89 101 11.9 White shrunken LS

104 Pb CMS 4A CS CS 110 86 105 18.1 White shrunken LS

88 100 12.0 White shrunken LS

Pb CMS 5A HS S 106 Pb CMS 6A

81 101 19.8 White PS

LS PS 110

Pb CMS 7A HS HS 85 105 19.0 White

109 LS

Pb CMS 8A CS CS 104 81 100 19.0 White MM 84

Pb CMS 9A PF PS 102 99 15.1 White shrunken LS

Pb CMS 10A CS 85 95 10.5 White shrunken LS 97 108 10.2 Yellowish

CS LS

105 Pb CMS 11A CS CS 112 Pb CMS 12A CS CS

91 111 18.0 Brownish LS 104 72

Pb CMS 13A CS 91 20.9 White shrunken LS

CS V20A

110 CS

86 108 20.4 White shrunken ELS CS 73

IR58025A 68

CS 82 17.1 White shrunken MM

CS 97 IR62829A

73 PS S 101 70 85 17.6 White shrunken MS

95 23.1 White shrunken LS

IR64607A CS CS 104 85 106 19.8 White shrunken LS IR64608A IR66707A IR67683A IR67684A IR68275A IR68280A IR68281A IR68886A IR68887A IR68888A IR68891A IR68895A IR68897A IR68899A IR68902A IR69628A

CS CS 104 HS

79 118 33.0 HS 112

CS CS 114 81 111 27.0 86 117 26.5

PS PS 100 83 HS

97 14.4 CS 104 92 105 12.4

PS PS 114 82 98 16.3 CS CS 95 PF

89 104 14.4 PF 105

HS S 87 100 13.0

99 CS

93 117 20.5 CS 88 84 93

PF 9.6

PF 88 92 102 9.8 CS CS 100 78 100 22.0 PF PF 98 76 99 23.2 CS CS 101 83 101 17.8 CS CS 106 CS

89 104 14.4 CS 103 95 101 5.9

Yellow shrunken MS White shrunken LS White shrunken LS White shrunken ELS Yellow shrunken MM Yellow plump LS White shrunken LS White LS Yellowish MS White shrunken MS White shrunken MM Yellowish LS Yellowish LS Yellowish LS White shrunken LS White shrunken LS

Genetically diverse lines included in the study displayed wide variation for days to flowering (73-114). Therefore these lines can be used to develop rice hybrids with desired maturity. The lines Pb CMS 12A, V20A, IR58025A, IR62829A, IR64608A, IR68895A, and IR68897A were typically dwarf in stature (<80 cm). The WA cytosterility reduced height by 5.9-33.0%) compared with the respective maintainer lines, whereas O. perennis cytoplasm resulted in a plant height decreased by 26.5% compared with the maintainer IR66707B.

The white anther trait in the completely sterile CMS line is desirable because it facilitates visual discrimi- nation between fertile and sterile plants at anthesis for practical hybrid seed production. Considering male sterility and anther color, Pb CMS 2A, 3A, 4A, 7A, 8A, 10A, 12A, 13A, V20A, IR58025A, IR64607A, IR66707A, IR67683A, IR68281A, IR68888A, IR68902A, and IR69628A are desirable CMS lines. From these, all except Pb CMS 7A, V20A, and IR68888A possess long slender grains. These CMS lines are also being screened for panicle and

a Completely sterile (CS) = 100% pollen/spikelet sterility, highly sterile (HS) = 99-99.9%. sterile (S) = 95-98.9%, partially sterile IPS) = 70-94.9%, partially fertile (PF) = <70%, b LS = long slender, LM = long medium, ELS = extra long slender, MM = medium medium, MS = medium slender.

potential, combining ability, and stigma exsertion rate, outcrossing

disease resistance, all traits that can render them commercially usable.

Comparison of regeneration frequency of green plantlets from in vitro culture of young panicles of wild rice

Guangxuan Tan, Xiaohui Yin, Lihui Shu, Guangchen He, and Lanjie Liao, College of Life Sciences, Wuhan University, Wuhan 430072, China

Wild Oryza species compose an important germplasm pool of high level genetic diversity and a number of economically important genes. However, most wild Oryza species prove recalcitrant in tissue and cell culture, which is an obstacle to the genetic manipulation of the valuable

germplasm. Recently, we cultured the young panicles of wild rice on different media and confirmed that the young panicles of wild rice have two development tendencies: dedifferentiation and redifferentiation. In both cases, green plantlet regenerations with high frequency were obtained for some species.

in the experiments. The young panicles (0.1-1.5 cm in length of the inflorescence) were plated either on the callus-inducing medium containing N6 + 2 mg 2,4-D L -l + 4.5% sucrose, pH 5.8 (method 1) or on the differentiating medium containing MS + 2 mg 6-BA L -1

+ 0.5 mg NAA L -1 + 3% sucrose, pH 5.8

Nine species of wild rice were used

(method 2). In the first culture method, the induced calli for 16 accessions of nine species of wild rice were transferred onto the differentiating medium. Green plantlets were obtained from six species (see table). The genomes of the species with regenerated plantlets were AA, A 1 A 1 , CC, CCDD and O. meyeriana with an unnamed genome. Until now, we have not obtained regenerated plantlets from O. eichingeri O. punctata, and O. brachyantha via callus redifferentiation. Green spots were observed on the calli of these species. Variation in the regeneration frequency also occurred among the accessions within the species. The regeneration frequency

10 IRRN 1997

Plant regeneration frequency from wild rice inflorescence cultured by two different methods. Wuhan, China.

Method 1 Method 2

Species Genome Origin No. Calli Regenerated Regeneration Panicles Regenerated Regeneration transferred plants (no.) frequency cultured plants frequency

(no.) (%) (no.) (no.) (%)

Oryza rufipogon

O. longstaminata O. punctata O. officinalis

O. eichingeri O. alta O. latifolia O.brachyantha O. meyeriana

AA

BBCC CC

CC CCDD CCDD

FF ?

China

Stolon Philippines Zambia India China

Sri Lanka Brazil Mexico Zambia China

2 3 8 4 18 5 18 6 13

17 15 20 12 14 16 34 15 18 21 15 24

0 0 2 0

10 0 4 0 0 0

10 0

10 3 0

14

0 0

11.1 0

58.8 0

20.0 0 0 0

29.4 0

55.6 14.3

0 58.3

20

22 35 15 17

37

30 27 23

15

18

21 26

13 8

0

12

12

12

18

90.0

95.5 74.3 50.0 76.5

0

40.0 66.7 52.2

80.0

a - not tested.

was only 11.1% in the normal type of O. rufipogon (number 5), but 58.8% in the stolon type of the same species.

In the second culture method, plantlets regenerated directly from the young panicles of wild rice that were cultured on the differentiating medium. Six species including 10

accessions were tested. Plantlets were obtained from five species except O. officinalis. The regeneration frequency was generally higher in this method than in the method via callus differentiation. Compared with plantlet differentiation via callus, direct regeneration of young panicles was much simpler

and the time needed shorter. Direct regeneration might present less risk to somatic variation than is common in in vitro tissue culture of the plant. There- fore, this method has potential in micropropagation, genetic manipulation, and cryopreservation of Oryza germplasm.

Determination of suitable time to Relationship between auricle distance and frequency of anthers in various phases.

select trisomics induced from

rice Trisomic (%) (%) anther culture of autotetraploid

Metaphase Metaphase Abnormal

Diploid

Auricle distance (cm) a -1.5 to + 1.5

Wu Minsheng, Genetic and Breeding Department, China Agricultural University, Beijing 100094, China

Use of primary trisomics has played an important role in genetics and breeding of rice. A great number of trisomics could be induced through anther culture of autotetraploid rice. In earlier work, trisomics of rice selected according to auricle distances from -2.5 cm to + 2.5 cm resulted in low selection efficiency. This paper reports on an efficient time to select trisomics.

Observed number 20 59 68.1 31.9 (bottle)

a Distance between auricle of the flag leaf and that of the next leaf from the flag leaf.

From 116 bottle anthers of young panicles of autotetraploid rice, we selected 100 panicles randomly per bottle. The results were as follows: 1) when auricle distance was from -1.5 cm to + 1.5 cm, all anthers were in metaphase and trisomics or diploids could be determined; 2) when auricle distance was from -2.5 cm to + 2.5 cm,

only 68.1% of the anthers were in

distance was from -2.5 cm to -1.5 cm or from + 1.5 cm to + 2.5 cm, no anthers were in metaphase (see table).

We concluded that an auricle distance from -1.5 cm to + 1.5 cm was better than from -2.5 cm to + 2.5 cm for selecting trisomics.

metaphase; and 3) when auricle

Vol. 22, No. 3 11

A 1 A 1

- - - -

- - - -

-

-

- -

- - - - - - - -

- -

- -

- -

Multisample rice cooker for evaluating eating quality

Hae Yeong Ryu, Crop Experiment Station, Rural Development Administration, Republic of Korea

Preparing cooked rice of several varieties or breeding lines to evaluate their eating quality characteristics is a difficult task. The error across samples is often high because each test entry must be cooked separately, usually at different times and using different apparatuses. To reduce this error, we developed a special cooker that uses indirect heat through water to subject the samples to the same conditions (see figure). One unit can cook nine samples simultaneously. This cooker may also be used to test the quality of small samples or samples from a single plant.

Grains and the appropriate amount of water are placed in the cooking cup. The base pan is filled with water to provide indirect heat for cooking. Cooking is done in two stages: first with water in the base pan for 20 min, then by removing the water and applying direct heat to the rice cups for 5 min. With two units, the cooking process of many samples can be continuous, with one having water in the base pan and the other without. About 120 samples can be evaluated in 1 d using two units.

Njavara: a unique rice race of the humid tropics

M. V. Menon and N. N. Potty Agronomy Department, College of Horticulture, Vellanikkara, Thrissur 680654, Kerala, India

Njavara is a unique land race of rice valued for its medicinal properties. It is used in treating circulatory, respiratory, and digestive ailments in ayurvedic medicine.

Multisample rice cooker.

We conducted an experiment to investigate the types of amino acids and the amounts of each in Njavara grain of the black-glumed and golden- glumed grain types grown under rainfed upland and lowland cropping situations compared with the common- ly grown traditional variety PTB20 during 1994-96 (see table). The black- glumed type had 192% more free amino acid content and the golden- glumed type 16% more than that of

PTB20 grown in the lowlands. The land race’s medicinal property appears to be attributable to the sulfur-containing amino acid, methionine, which is involved in the metabolic pathway of the biosynthesis of thiamine (Vitamin B 1 ), the deficiency of which causes beriberi. Black-glumed Njavara is richer than pulses in free amino acid content, entitling it to be called a proteinaceous cereal.

12 IRRN 1997

Grain quality

Total free amino acid content and some probable amino acids present in Njavara as compared with PTB20 grain.

Condition Duration (d) Amino acids identified Total free

amino acid content (mg g -1 )

Black-glumed Njavara Wetland

Open upland

50-70% shaded upland


Golden yellow-glumed Njavara Wetland

Open upland



PTB20 in wetland situation

99

94

93

93

103

95

102

99

120

DL-2-amino-N-butyric acid and DL-isoleucine L-histidine monohydrochloride. L-leucine, DL-methionnine and L-proline DL-2-amino-N-butyric acid, L-cysteine hydrochloride monohydrate, DL-methionine and DL-isoleucine DL-threonine, DL-methionine and L-leucine

L-histidine monochloride. L-ornithine monohydrochloride and DL-isoleucine DL-2-amino-N-butyric acid. L-proline, DL-methionine and L-leucine DL-threonine, DL-methionine and DL-isoleucine DL-threonine, DL-methionine and L-leucine DL-serine

0.316

0.670

0.814

0.334

0.089

0.424

0.169

0.164

0.183

New rice breeding lines with multiple pest resistance

D. J. Pophaly A. Gupta, and G. R. Sahu, Entomology Department, Indira Gandhi Krishi Vishwavidyalaya, Raipur 492012, India

Brown planthopper (BPH) ( Nilaparvata lugens ), gall midge ( Orseolia oryzae ), and

bacterial leaf blight (BLB) disease

are widespread in the Chhattisgarh region of Madhya Pradesh. To overcome this major constraint to selecting proper varieties in the integrated pest management program, we sought to develop new breeding lines with multiple pest resistance.

( Xanthomonas oryzae pv. oryzae [Xoo])

Seven promising breeding lines of the F 8 generation were studied for stability to pest resistance and agronomic characters during the 1993-95 monsoon seasons. In the field, 30-d-old seedlings of these test lines were transplanted at 10- × 20- cm spacing in two 2-m rows along with checks TN1 (susceptible) and Ptb33 (resistant). At maximum tillering stage, all plants were inoculated with Xoo by clip inoculation method. Recommended agronomic practices were followed to raise the crop. Observations were recorded for all hills 50 d after transplanting when gall midge incidence peaked. Likewise BLB-inoculated plants were observed for disease symptoms at maximum disease pressure.

resowing the next wet season. Grain and plant characters were also recorded. In the glasshouse, these lines were screened against N. lugens; feeding and probing mark studies were also carried out.

Except for pureline IET6286, all seven breeding lines were derived from a widely cultivated variety Ruchi, which is resistant to gall midge and moderately resistant to BLB (Table 1). IR64 is resistant to the Raipur BPH insect population. RM1 (Raipur mutant), also used as a donor, is resistant to BLB but susceptible to gall midge. IR19661-23-3-2 and IR27325- 111-2-1 are gall midge-susceptible but

At harvest, grain was collected for

Table 1. Agronomic characters of advanced breeding lines.

Breeding line Parentage Test weight (g) Duration Hull Kernel Grain Plant Plant 1,000 seed (d) color color dimension a type b color

R712-1-65-1-1 R710-3-37-1-1-1 IET6286 R746-2-34-1-2-1 R714-2-9-3-2-2 R714-1-19-1-5-1 R720-1-91-2-1-1 R714-3-103-1-3-2

TN1 (susceptible check) PTB 33 (resistant check

for BPH and BLB)

Ruchi/lR19661-23-3-2 33 Ruchi/IR27325-111-2-1 31

IR64/Ruchi RMl/Ruchl RMl/Ruchi Ruchi/RM1 RMl/Ruchi

23 24 28 27 26 31

23 18

125 125 155 125 125 125 130 128

120 185

Light golden Light golden Deep golden Straw Straw Straw Straw Light golden

Straw Straw

White White White White White White White White

White White

LS LS LS LS LS LS LS LS

MS LS

SD SD T

SD SD SD SD ST

D T

Green Green Green Green Purple Purple Purple Purple ring in green plant Green Green

a LS = long slender, MS = medium slender. b SD = semidwarf, T = tall, D = dwarf.

Pest resistance

-

- -

Vol. 22, No. 3 13

Table 2. Reaction of rice breeding lines against brown planthopper, gall midge, and bacterial leaf blight.

Breeding line Brown planthopper Gall midge Bacterial leaf blight

Plant

score (mm 2 female -1 marks Score Rating Score Rating damage a Rating b Av feed c Av probing d (1993-95) e (1993-95) e

in 24 h) seedling -1

R712-1-65-1-1

IET6286

R714-2-9-3-2-2 R714-1-19-1-5-1

R714-3-103-1-3-2 TN1 (susceptible check) PTB33 (resistant check for BPH and BLB)

R710-3-37-1-1-1

R746-2-34-1-2-1

R720-1-91-2-1-1

1.00 2.58 3.20 3.31 3.87 3.94 4.15 4.30 9.00 1.08

R R MR MR MR MR MR MR S R

15 35 26 33

30 20

99 22 24 17

57 25 160 18

10 42

0 0 0 0 0 0 0 0 9 9

R R R R R R R R S S

3 1 3 1 1 1 1 1 9 1

MR R MR R R R R R S R

a Based on 4-7 replications. b R = resistant, MR = moderately resistant, S = susceptible. c Based on 16-22 females. d Av based on 5-6 seedlings. e Based on 120 plants.

resistant to BLB disease and are used as donors of BLB resistance.

All seven breeding lines were found resistant to Raipur gall midge populations (Table 2). For BPH, two varieties, R712-165-1-1 and R710-3-37- 1-1-1, were resistant. The BPH insect feeding on these two varieties was much reduced (15 and 26 mm 2 in 24 h) compared with susceptible check TN1

(160 mm 2 in 24 h). These breeding lines may possess an antifeedant chemical. Consequently, they also exhibited the highest probing marks (35-36 seedling -1 ) compared with TN1 (18 seedling -1 ). We speculate these lines may have built-in genetic resistance to BPH.

Only R710-3-37-1-1-1 is resistant to gall midge, BLB, and BPH and has all the desirable agronomic characters. It is

a semidwarf with white kernels and long, slender grains. Its hulls are light gold. It matures in 125 d, and its 1000- seed weight is 21 g.

Breeding lines R746-2-34-1-2-1,

1-91-2-1-1, and R714-3-103-1-3-2 are moderately resistant to BPH and resistant to gall midge; IET6286 is moderately resistant to BLB.

R714-2-9-3-2-2, R714-1-19-1-5-1, E720-

Cross-fertility and pathogenicity of the blast fungus Magnaporthe grisea Sac. isolated from

cultivated and wild rice in Yunnan

Li Chengyun, Yang Qinzhong, Zhen Fengping, Lou Chaoxi, and Li Jingbin, Yunnan Academy of Agricultural Sciences, Kunming, Yunnan 650205, China; and Kazou Ise, Japan International Research Center for Agricultural Sciences, Tsukuba, Ibaraki 305, Japan

Yunnan Province of China, a cradle of Asian cultivated rice, abounds in germplasm of both rice and rice blast fungus ( Magnaporthe grisea ). Many field races on Japanese differential rice varieties, and some field isolates from upland rice, can form the sexual stage under laboratory conditions (Li et al 1993).

Table 1. Perfect state formation of Magnaporthe grisea isolate from several plants in Yunnan. a

Host plant Cultivated rice Wild rice Goose grass Finger grass Finger millet

Cultivated rice Wild rice – – Goose grass + + + Finger grass + + Finger millet +

+ + + – + – –

a + = formation; – = no formation.

Table 2. Pathogenicity of Magnaporthe grisea isolates from several plants in Yunnan. a

Host plant Cultivated rice Wild rice Goose grass Finger grass Finger millet

Cultivated rice S S R R R Wild rice R S R R R Goose grass R R S R S Finger grass R R R S R Finger millet R R S R S

a S = pathogenic; R = nonpathogenic.

14 IRRN 1997

Pest resistance—diseases

- -

- -

We made more than 3000 combinations by using the strains of M. grisea isolated from cultivated rice ( Oryza sativa L.), common wild rice ( O. rufipogon ), goose grass ( Eleusine indica Gaertn.), finger grass ( Digitaria sanguinalis Scop.), and finger millet ( Eleusine coracana Gaertn.) in Yunnan Province.

of strains isolated from upland rice is higher and wider than those isolated from lowland irrigated rice, but only one strain isolated from wild rice produced ascospores when crossed

The results show that cross-fertility

with the strain isolated from lowland irrigated rice, and the mating type was MATI-1. Strains isolated from wild rice were crossed with strains isolated from goose grass, finger grass, and finger millet, too, but no ascospores were made in these combinations (Table 1).

Cross-fertility and pathogenicity of strains isolated from common wild rice were identical to those of strains isolated from rice (Table 2). We speculate that strains isolated from common wild rice are nearer to those isolated from cultivated rice than in other plants in cross-fertility and pathogenicity.

Fifteen hermaphroditic isolates have been found in Yunnan Province, and 13 of these have been isolated from upland rice. The hermaphroditic isolates of MATI-1 were crossed with the hermaphroditic isolates of MATI-2. Half the combinations produced mature perithelia, and 2-3% of the ascospores were viable. Through a series of backcrosses with field isolates, 20-30%, viable ascospores were obtained. These field isolates and laboratory strains can be used in the study of inheritance of pathogenicity and the genetic analysis of avirulence in the fungus.

Performance of midland rice varieties in a blast hot spot

H. K. Ramappa, N. Shivakumar, N. M. Poonachha, Agricultural Research Station (ARS), Ponnampet, Coorg District; and T. B. Anilkumar, Regional Research Station, VC Farm, Mandya 571405, Karnataka, India

Blast ( Pyricularia oryzae ) is a major problem in almost all rice-growing areas in Karnataka, particularly in the high- rainfall malnad region where it is a major reason for low yields there. To find high-yielding, blast-resistant varieties, 27 rice genotypes were evaluated over 3 yr at ARS in Ponnampet, a hot spot for blast.

Thirteen midland varieties with the standard local variety Intan were sown on 10 Jun 1992, 22 Jun 1993, and 22 Jun 1994 and transplanted on 28 Jul 1992, 30 Jul 1993, and 29 Jul 1994, respectively. Heavy rainfall, a common occurrence, delayed transplanting. The genotypes were planted in a randomized complete block design in plots 10 × 7.5 × 9 m. Neck blast incidence was recorded twice during the grain development stage. The plot yields were converted to t ha -1 .

The mean neck blast incidence was significantly highest for Intan (69.37%), with the least incidence for IYT(SHW)91/ 10609 (see table). Among the varieties, mean yield was significantly lower for

Reaction of midland varieties to neck blast. a ARS, Ponnampet, India. 1992-94.

Neck blast incidence (%) Rice yield (t ha -1 )

1992 1993 1994 Mean 1992 1993 1994 Mean Genotype

IRLON90/18 KHP2 IYT (SHW) 91/10609 IMRYT91/1708 CTH6 IET7/7191 RR12 KHRS55 Jaya IRLON90/140 Karna KHRS26 IRLON90/98 Intan

Mean of 3 yr

Comparison 2 T × Y Mean

9.77 ctg 18.39 dct 3.71 g

20.33 ct 0.83 fg

22.50 cde 16.23 dg 28.40 bcd 21.67 cde 15.38 dg 40.41 b 33.45 bc 25.55 cd 56.43 a

9.67 cd 23.87 cd 12.32 cd 15.25 de 5.14 d 8.22 e 8.25 cd 7.08 e

16.02 cd 9.72 e 7.66 cd 13.17 de

20.10 c 4.39 e 37.26 b 14.63 de 12.79 cd 16.72 de 17.31 cd 6.90 c 67.64 a 31.57 c 59.66 a 24.87 cd 14.12 cd 100.00 a 68.43 a 83.24 b

Blast incidence

SE LSD (%) 5.94 11.82

14.43 3.9 ab 4.9 a 3.0 ab 3.9 15.32 3.4 abc 3.0 bc 3.4 ab 3.3 5.69 3.1 bcd 2.8 cd 3.5 ab 3.1

11.89 2.9 cde 3.2 bc 3.4 ab 3.2 11.19 4.2 a 1.6 atg 3.7 a 3.2 14.44 2.3 def 3.1 bc 3.1 ab 2.8 13.57 2.2 dg 2.7 cd 2.9 ab 2.6 26.76 2.9 cde 2.0 def 3.7 a 2.9 17.06 2.0 cfg 2.3 cde 3.0 ab 2.4 13.20 2.0 cfg 1.9 dg 3.1 ab 2.3 46.54 1.2 g 1.3 fg 2.8 ab 1.8 39.33 1.4 fg 0.9 g 2.5 b 1.6 46.56 2.3 def 3.9 b 0.1 c 2.1 69.37 1.2 a 0.9 g 0.9 c 1.0

Yield

SE LSD (%) 444.49 884.18

a Within a column, figures followed by a common letter are not significantly different from each other at the 5% level.

Intan, with the exception of Karna and between Ratna and ARC10659, and KHRS26. In contrast, IRLON90/ 18 had 1-2, IYT(SHW)91 /10609 is a cross

for Karnataka. Blast can cause up to Karnataka. seasons, making them extremely useful genotype for the midland region of very high disease pressure over three IRLON90/18, it should prove a good tently yielded more than 3 t ha -1 under low blast score and yielded the same as IMRYT91/1708, and CTH6—consis- IYT(8HW)91/10609 consistently had a IRLON90/18, IYT(SHW)91/10609, IMRYT91/1708, and CTH6. Because IR8263-28-1. These genotypes— a par with KHP2, IYT(SHW)91/ 10609, KHP2 is a cross between BG90-2 and a mean yield of 3915 kg ha -1 and was on

IRLON90/18 is a cross between 80%) yield loss when the disease BKNFR76106-16-0-1 and IR19961-131- severity is 9.

Vol. 22. No. 3 15

Effect of water deficit on plant water status, growth, and yield of rice

P. K. Sharma, G. Singh, and R. M. Bhagat, Soil Science Department, Himachal Pradesh Agricultural University, Palampur 176062, India

Recent research has challenged the traditional concept of keeping ricefields flooded throughout the cropping season. We conducted a glasshouse experiment to investigate the limit to which rice plants can be water-stressed without incurring significant yield losses. Our aim was to find ways to lessen the amount of water needed for irrigating rice.

Air-dried silt loam soil, passed through a 4-mm screen, was packed into 0.82-m-long and 0.50-m-diam metal drums, and given two wetting and drying cycles for proper settling. The soil had 264 kg available N ha -1 , 24.7 kg Olsen's P ha -1 , and 281 kg 1 N ammonium acetate-extractable K ha -l . Twenty-five-day-old seedlings of cultivar HPU741, two seedlings hill -l and five hills drum -1 , were transplanted. Each drum was fertilized with 100 kg N ha -1 as urea, 17 kg P ha -1 as superphosphate, and 33 kg K ha -1 as potassium chloride. The soil in each drum was kept submerged with 30 mm water for the first 7 d. Thereafter, irrigation was regulated to achieve four water regimes in the root zone—30 mm continuous submergence of soil, and irrigation to the same water depth

Relationship between xylem water potential of rice and soil matric potential at 15 cm depth.

when matric potentials at 0.15 m soil

potential, the xylem water potential of measured with mercury tensiometers. With every unit decrease in soil matric depth reached -10, -20, and -30 kPa, as potential at 0.15 m depth (see figure).

The xylem water potential of rice rice plants decreased by 17.7 kPa. The plants was determined before each xylem water potential of continuously irrigation at 0700 h with a pressure watered plants was around -200 kPa. chamber apparatus (Soil Moisture

potential, but decreased at or below and straw yield, and yield parameters at saturation and -10 kPa matric potential. Root and shoot growth, grain yields of rice did not differ significantly soil matric potential and xylem water grain weight, and grain and straw A relationship was developed between panicle weight, spikelet sterility, 1000- Equipment Corp., Santa Barbara, USA).

Shoot growth rate, plant height,

were determined. Root mass density matric potentials of -20 kPa (see table). (RMD) was determined at harvest by The RMD decreased progressively with collecting soil cores, 0.15 m long and the increase in water deficit. But lower 0.10 m diam, 1 drum -1 , from the central RMD at -10 kPa compared with plant in each drum. continuous soil submergence did not

positively correlated with soil matric results indicate that ricefields do not The xylem water potential was affect grain and straw yield of rice. The

Effect of different soil water regimes on growth and yield of rice. Palampur, India.

Matric Shoot growth rate (mm d -1 ) Plant RMD b Panicle Spikelets Spikelet 1000-grain Grains Straw Total potential height (kg m -3 ) weight panicle -1 sterility weight (g hill -1 ) (g hill -1 ) water use (kPa) 1-8 WAT a 8-12 WAT (cm) (g) (no.) (%) (g) (mm)

0 12.8 1.7 103.8 3.0 3.5 117 6 32.2 13.9 29.8 485 –10 12.6 1.7 103.0 2.8 3.6 114 6 32.5 13.5 29.1 418 –20 11.8 1.4 101.0 1.8 3.1 113 9 25.8 12.7 27.4 372 –30 11.6 1.2 99.0 1.6 3.1 109 11 25.7 12.6 27.2 322

CD (0.05) 0.3 0.2 0.8 0.2 0.3 5 1 1.8 0.6 0.9 22

a WAT = weeks after transplanting. b RMD = root mass density.

Stress tolerance — drought

16 IRRN 1997

need to be continuously flooded

submerged under 30 mm of water. arrives in about 3-4 d in medium- crop can be safely irrigated at -10 kPa water used to keep soil continuously observed in some field experiments, throughout the cropping period; a rice The procedure saved about 16% of the decline in rice yield. This suction, as

textured soils in subtropical climates. matric suction without causing any

Mass screening and identifica. Photooxidation and shading tolerance in different rice varieties.

tion of rice germplasm tolerant of light and temperature stress Variety

Dry weight plant -1 (g) Photooxidative treatment S/N×100%

Natural light (N) Shading (S) Chl content (mg dm -2 ) Grade a

Li Xia and Jiao Demao, Institute of Agrobio- logical Genetics and Physiology, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China

Rice adaptation to light and temperature stresses is the basis of stable yield. Few simple and easy techniques exist to test rice germplasm for tolerance for these stresses.

We screened rice germplasm for shading tolerance using the method of Murty (1992). We divided the identified varieties into two groups during elongation stage. One group was placed in natural light, the other in the shade (1/5 natural light). After 14 d, the dry weight of the two groups was measured at the booting stage. The ratio of dry weight under shading to that under natural light was used as the shading tolerance index.

At the same time, germplasm was screened for tolerance for photooxidation using the method of Jiao (1992). Mature rice leaves were detached at heading stage and submerged in a white tray filled with water containing 5 µmol CO 2 and 350 µmol O 2 under sunlight at 30-35 °C for 5-7 d. A transparent glass bar covered the - leaves to prevent floating. Photo- oxidation-tolerant varieties whose chlorophyll contents were 3.0-4.78 mg dm -2 were graded 1-2, whereas sensitive varieties whose chlorophyll contents were 0.8-2.2 mg dm -2 were graded 4-5 (see table).

rice germplasm accessions using this technique. Results indicated four photosynthetic ecological types

From 1993 to 1995, we identified 41

Yue A (I) Yue A/R3049 (I) R3049 (I) Yue A/R3043 (I) R3043 (I) Yue A/R3034 (I) R3034 (I) Yue A/R3035 (I) R3035 (I) Yue A/R3044 (I) R3044 (I) Yue A/R437 (J) R437 (J) Yue A/J204 (J) J204 (J) Yue A/320500 (J) 320500 (J) Yue A/30152 (I) Yue A/34077 (I) 34077 (I) Yue A/42525 (I)

Liuqianxin S/JW201 (J)

JW201 (J) Liuqianxin S (J)

JW207 (I) Liuqianxin S/JW207 (J) 276 (J) Liuqianxin S/276 (J) Pelai 64S (I)

02428 (J) Yayou 2 (J) B HX-3 (I) Minghui 63 (I) Shanyou 63 (I) D Jin gang 30 (I) Xiangxian (I) F Tsukushibare (J) C Corn-rice (I) Nanjing 14 (I) E Wuyugeng (J) A Peiai 64S/JW201 (J)

5.37 ± 0.12 5.15 ± 0.14 5.19 ± 0.15 3.26 ± 0.15 4.33 ± 0.65 4.38 ± 0.53 5.14 ± 0.21 6.32 ± 0.25 4.90 ± 0.13 5.75 ± 0.11 8.56 ± 0.25 6.35 ± 0.35 6.06 ± 0.15 3.85 ± 0.20 5.56 ± 0.12 6.88 ± 0.20 5.58 ± 0.30 3.80 ± 0.17 4.65 ± 0.27 4.42 ± 0.29 6.29 ± 0.21

14.60 ± 1.68 15.50 ± 2.15 13.70 ± 1.89 12.10 ± 1.93 13.90 ± 2.11 14.40 ± 2.99 18.00 ± 2.29 16.20 ± 2.44

8.70 ± 0.53 10.50 ± 1.41 28.01 ± 3.68

1995 2.51 ± 0.12 3.48 ± 0.17 1.78 ± 0.12 2.68 ± 0.13 2.31 ± 0.15 3.17 ± 0.21 2.16 ± 0.21 3.33 ± 0.31 1.64 ± 0.11 3.63 ± 0.29 3.29 ± 0.25 1.94 ± 0.15 2.32 ± 0.19 2.46 ± 0.13 1.61 ± 0.10 2.40 ± 0.12 3.03 ± 0.31 1.94 ± 0.17 1.92 ± 0.15 2.81 ± 0.21 2.75 ± 0.19

1994 6.90 ± 0.49 7.90 ± 0.58 8.80 ± 0.70 6.00 ± 0.57 7.40 ± 0.49 6.50 ± 0.35

10.50 ± 1.51 6.20 ± 0.53

1993 5.90 ± 0.52 6.60 ± 0.39

16.15 ± 3.10

46.72 1.45 ± 0.10 67.57 1.66 ± 0.11 34.24 2.10 ± 0.21 82.17 2.53 ± 0.17 53.31 3.36 ± 0.19 72.44 1.77 ± 0.23 41.95 2.84 ± 0.29 52.58 0.81 ± 0.09 33.54 1.22 ± 0.10 62.91 2.49 ± 0.14 38.45 0.84 ± 0.08 30.59 1.45 ± 0.09 38.32 2.24 ± 0.17 64.51 2.45 ± 0.10 28.92 2.21 ± 0.13 34.94 1.99 ± 0.12 54.30 1.28 ± 0.13 51.05 1.49 ± 0.10 41.29 2.58 ± 0.15 63.50 3.14 ± 0.27 43.80 2.09 ± 0.19

47.30 3.50 ± 0.25 51.00 3.31 ± 0.30 64.20 3.03 ± 0.25 49.60 2.21 ± 0.18 53.20 2.33 ± 0.10 45.10 3.28 ± 0.27 58.30 1.48 ± 0.09 38.30 1.91 ± 0.11

67.80 4.78 ± 0.35 62.90 3.93 ± 0.59 57.66 2.56 ± 0.19

16.05 ± 2.97 5.56 ± 0.29 34.61 2.27 ± 0.21 11.50 ± 1.87 7.90 ± 0.48 68.70 1.73 ± 0.17

8.50 ± 0.36 4.30 ± 0.31 50.60 1.03 ± 0.16 11.40 ± 2.16 3.10 ± 0.30 27.20 1.20 ± 0.11

7.00 ± 0.36 2.10 ± 0.21 30.30 3.03 ± 0.31 4.60 ± 0.38 3.30 ± 0.21 71.70 1.36 ± 0.10 8.70 ± 0.47 2.90 ± 0.19 33.30 2.75 ± 0.17 7.00 ± 0.41 4.10 ± 0.35 58.60 3.78 ± 0.43

16.10 ± 2.74 6.20 ± 0.58 38.50 1.40 ± 0.10

5 4 4 3 2 4 3 5 5 3 5 5 4 3 4 4 5 5 3 2 4

3 3 3 4 3 4 5 4

1 2 3 3 4 5 5 2 5 3 2 5

period was from elongation to booting. Photooxidative treatment was conducted at booting stage for 6 d.

a Grades (scores): 1 = green; 2 = tip is yellowish; 3 = 1/3 is yellowish; 4 = 1/2 is yellowish; 5 = whole leaf is yellowish. Shading

adapted to light intensity. One was

02428, Wuyugeng, and indica-japonica thetic rate at high (40 °C) and low intensities, including japonica rice During the heading stage, photosyn- adapted to a wide range of light hybrid rice YueA/ R 3043, Yayou 2.

temperatures (15 °C) was determined

Stress tolerance—adverse temperature

Vol. 22, No. 3 17

Differences in photosynthetic rates of six rice varieties under low (15 ºC). A = Wuyugeng, B = Yayou 2, C = Tsukushibare, D = Shanhou 63, E = Nanjing 14, F = Xiangxian.

using a Clark O 2 electrode and compared with the photosynthetic rate at optimum temperatures of 30-35 °C. The

ratio of photosynthesis under high and low temperature to that of optimum temperature was represented as a high- or low-temperature tolerance index. Six varieties were selected for their tolerance for temperature stress (see figure). The results showed that japonica rice Wuyugeng and indica- japonica hybrid Yayou 2 were tolerant of both high and low temperatures. Their photosynthetic rates were stable. Under field conditions, japonica rice Wuyugeng is tolerant of light and temperature stresses and its yield has been relatively stable at more than 9 t ha -1 .

Wuyugeng is now one of the main rice varieties in Jiangsu Province, China. On the contrary, indica rice Xiangxian, which is sensitive to light and temperature stresses, has not been grown in Jiangsu.

In general, the types adapted to wide ranges of light and temperature were mostly japonica and indica- japonica rice varieties. In the region near the middle or lower reaches of the Yangtze River, selecting japonica rice and indica-japonica hybrid rice varieties adapted to wide ranges of light and temperature stresses may be an approach for rice breeders to use for obtaining high and stable yield.

Variation in salt tolerance among rice mutants and varieties based on yield attributes

L. M. Gonzalez, R. Lopez, and R. Ramirez, Nuclear Laboratory, Agricultural Research Institute Jorge Dimitrov, Gaveta Postal 2360, Bayamo 85100, Granma, Cuba

Around 100,000 of the 160,000 ha determined to be suitable for rice production in Cuba are affected by salt. We have therefore focused our rice breeding program on obtaining salt- tolerant genotypes.

We evaluated 9 mutants obtained from the J-112 variety through gamma radiation and 19 varieties for salt- tolerance field studies. The genotypes were studied in specially designed 3- × 3- × 1-m test plots in saline soil (plastic dark Gley Typic, with pH 7.44, 2000 ppm of total soluble solids, 0.90% organic matter, 0.003% N, 5.51 mg P100 g -1 soil, and 11.68% mg K 100 g -1 soil), and in nonstressed productive soil over two seasons. The experiment was laid out in a randomized block design with four replications. The crops were managed following local practices. Data on agronomic attributes (panicle length, panicle weight, filled grains

Clustering pattern among 28 rice genotypes and cluster means based on the saline stress tolerance indexes for different characters.

Cluster Strains in each cluster Panicle length

A Theoretical check 100 B RM12, RM62, RM41, 92

RM66, RM114, RM157, RM72, RM120, RM153

C IACUBA-26, Caribe I, 88 lR5931, IR42, J112, 4024,2006, CP3-C2, J104

D Amistad-82, 6140 70 E 2005, 4014, IR8, 4032, 62

4034, MI-48, Perla

Saline stress tolerance index (%) based on

Panicle Filled grains 1000-grain Grain weight panicle -1 weight yield

100 100 100 100 90 90 88 50

80 85 83 45

52 80 77 39 45 72 70 34

panicle -1 , 1000-grain weight, and grain yield) were collected from 10 randomly selected plants in each replication. Routine research. Reports of

For all dates collected in the experiment, the saline stress tolerance index was calculated. To study the genotypic variation in the above characters, the data were processed accepted. Examples are single- further by using cluster analysis season, single-trial field through Euclidian distance, including a experiments. Field trials should be theoretical check (100%) for all saline

season, in multiple seasons, or in stress tolerance indexes). repeated across more than one

reduced agronomic attributes in all appropriate. All experiments should

genotypes. Based on the Euclidian include replications and an interna-

distance values, the population of 28 tionally known check or control

genotypes was grouped in 4 clusters (B, treatment.

C, D, E) (see figure), indicating a great

screening trials of varieties, fertilizer, cropping methods, and other routine observations using standard methodologies to establish local recommendations are not ordinarily

In general, salinity markedly more than one location as

Stress tolerance — adverse soils

18 IRRN 1997

Dendrogram of clustering for radiomutants and varieties based on saline stress tolerance index for yield and yield attributes.

variability for salt tolerance. Cluster B, consisting of 9 mutants from the J-112 variety, had the highest mean for all attributes (see table), as well as the minimum value of intercluster distance with a theoretical check (cluster A), a result indicating that the mutants grouped in it were the most tolerant of those tested.

2 genotypes, respectively. These genotypes were intermediate in salt tolerance.

E. These genotypes present a lower value of means for all attributes and a maximum intercluster distance value with cluster A (theoretical check), indicating they are the most susceptible. In this cluster were two varieties (MI 48 and IR8) that many breeders use as a susceptible checks. This finding confirmed our method used in varietal tolerance evaluation.

Our results indicated that the mutants grouped in cluster A were higher than the parent and other varieties for salt tolerance, indicating the possibility of generating heritable variation for this attribute in rice through gamma radiation. The varieties hold promise in salt-affected areas and may also serve as donor parents in breeding for salt tolerance.

Clusters C and D consisted of 10 and

Seven genotypes comprised cluster

Water relations in rice seedlings in saline medium

L. M. Gonz lez and R. Ram rez, Soil Science and Agricultural Chemistry Department, Agricultural Research Institute Jorge Dimitrov, Gaveta Postal 2360, Bayamo 85100, Granma, Cuba

We evaluated the seedling water content (SWC), leaf relative water content (LRWC), transpiration intensity (TI), and the cell sap concentr ation (CSC) in four rice varieties, differen- tiated by the degree of their salt tolerance. Pokkali and IR24 were tested

Effect of salinity on some water relation variables in rice seedlings. Granma, Cuba. a

for salt tolerance and MI 48 and Perla for susceptible behavior.

Seedlings of four varieties were sown in nutrient solution under controlled laboratory conditions using Hoagland nutrient solution (control) and Hoagland nutrient solution

Seedling water content (%) Leaf relative water content (%) Transpiration (mg H 2 O mg DW -1 h -2 ) Cell sap concentration (% TSS) b

Control Stress Control Stress Control Stress Control Stress Variety

Pokkali 89 ± 0.84 82 ± 1.16** 88 ± 0.12 80 ± 0.90** 5.1 ± 0.10 3.6 ± 0.52** IR42

5.9 ± 0.06 9.1 ± 0.17*** 87 ± 0.76 80 ± 0.68** 87 ± 0.51 78 ± 1.25** 4.8 ± 0.65 3.2 ± 0.45** 5.5 ± 0.22 8.9 ± 0.03***

MI 48 89 ± 0.47 71 ± 0.46*** 86 ± 0.23 69 ± 0.12** 6.0 ± 0.10 2.7 ± 0.22*** 5.2 ± 0.10 8.2 ± 0.20*** Perla 92 ± 0.47 69 ± 0.48*** 85 ± 0.82 69 ± 0.70** 5.4 ± 0.38 1.9 ± 0.06*** 5.1 ± 0.20 8.3 ± 0.47***

a ** and *** = significant differences for P <0.01 and P <0.001 by the Student-t test. b TSS = total soluble salts.

Vol. 22, No. 3 19

enriched with NaCl (0.7%,). The pH was kept at 5.0. The SWC, LRWC, and TI were determined by gravimetric methods and the CSC by refractometry in five replications at 21 d after planting. The SWC, LRWC, and TI significantly diminished under salinity stress in all varieties (see table) because plants could not absorb adequate water. The TI was more pronounced than SWC or LRWC. Plants adjust their

T1 as a defense mechanism to compensate for water loss.

Salt-tolerant varieties Pokkali and IR42 had a reduction of 6-7% for SWC, 6-8% for LRWC, and 29-30% for TI, whereas in the salt-sensitive MI 48 and Perla, SWC decreased by 18-20%, LRWC by 16-17%, and TI by 60-67%. Varietal differences in salinity tolerance can be measured using these three plant water parameters.

CSC is another important factor to be considered in plant-water relations. An increase (66-67%) of CSC was observed in all varieties under stress conditions. Increase in CSC is attributed to an extensive accumulation of hydrophilic, osmotically active ions in cells and should not be regarded as a defense mechanism of seedlings under stress conditions.

Te-Shan-Ai No. 2, a high-yielding rice in China

S.-C. Zhou, R.-W. Miao, W. Ke, Y.-H. Jiang, J.-W. Chen, Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong 510640, China

Te-Shan-Ai No. 2 (TSA), a high-yielding rice variety with wide adaptability, was developed by researchers at the Rice Research Institute, Guangdong Aca- demy of Agricultural Sciences. It was released for cultivation in China in June 1996.

In the 1990-91 regional tests in southern China, the mean grain yield of TSA was 8.6 t ha -1 , 14%) more than the local check and 5% more than the hybrid check. In the 1990-93 regional tests in Guangdong and Guizhou provinces, the mean grain yield was 6.9 t ha -1 , 14%) more than the local check in double-cropped areas; mean grain yield was 8.4 t ha -1 , 13%) more than the

local check in single-cropped areas (Table 1). TSA was registered in March 1992 and July 1995 by the Guangdong and Guizhou Crop Variety Evaluation committees, respectively.

TSA is derived from the cross Te- qing /Shan-Er-Ai. It successfully combines the high-yield characteristic of the female and the wide adaptability characteristic of the male. In large-scale

given high yields but has also shown wide adaptability in both single- and double-cropped areas in southern China. The variety was planted on

China. In 1994, it became a new check for regional trials. In 1996, it yielded at least 10% more than all other varieties

TSA is moderately resistant to blast and resistant to bacterial blight. The average amylose content is 26.4%, and the alkali spreading value is 7.0 (Table 2). One major gene and seven

demonstrations, TSA has not only

685,500 ha in 1991-96 in southern

tested (Table 1).

minor genes located on seven chromosomes seem to control the semidwarf character of TSA. The character grain weight plant -1 is related to five quantitative trait loci located on chromosomes 1, 2, 3, 4, 5, and 8. A major gene located on chromosome 4 and a minor gene located on chromosome 2 may control the number of panicles plant -1 (Lin et al 1996).

Table 2. Grain quality characteristics of Te-Shan-Ai No. 2.

Grain length (mm) 5.3 Grain width (mm) 2.8 Length-width ratio 1.9 Chalky grain (%) 100.0 Chalky area (%) 12.0 Brown rice (%) 81.3 Milled rice (%) 73.5 Head rice (%) 58.4 Gelatinization temperature (ºC) a 7.0 Gel consistency (mm) 32.0 Amylose content (%) 26.4 Protein content (%) 9.2

a Indexed by alkali spreading value: low, 6--7; intermediate, 4-5.

Table 1. Performance of Te-Shan-Ai No. 2 (TSA) in regional tests in China. 1990-96.

Character South China Guangdong Guizhou South China

1990 1991 1990 1991 1992 1993 1996 (8 sites, 5 provinces) (19 sites, 11 provinces) (17 sites) (21 sites) (8 sites) (8 sites) (16 sites, 10 provinces)

Grain yield (t ha -1 ) Grain yield over check (t ha -1 ) Growth duration (d) Growth duration over check (d) Plant height (cm) Productive panicles m -2 (no.) Spikelets panicle -1 (no.) Filled grains panicle -1 (no.) Seed set (%) 1000-grain weight (g)

8.8 +5.2 b

139.5

104.4 -1.0

351.0 122.8 101.9 83.0 26.6

8.3 +14.1 c

138.2 +1.9

105.6 312.0 127.2 104.0 81.8 26.4

6.7 +8.4 d

136.0 +2.0 97.8

307.5 109.4 93.5 85.5 26.9

7.2 +19.8 d

132.0 +3.0 99.2

388.5 117.7

96.2 81.7 26.6

9.4 +11.9 c

155.6 +2.7 85.7

294.0 143.8 124.2 86.4 26.9

7.3 +14.9 c

155.3 +3.5 94.2

297.0 126.4

99.7 78.9 26.9

8.4 a

139.2

104.6 282.0 132.6 111.6 84.2 27.2

a TSA ranked first and outyielded all other varieties significantly at the 1% level. b Check is Shanyou 63. c Check is Gui-Chao No. 2. d Check is Shan-Er -Ai.

Integrated germplasm improvement—Irrigated

20 IRRN 1997

Cilosari: a new rice variety selected. A semidwarf mutant, SM- released in Indonesia through cross hybridization of the mutant line with IR36

~ ~~

268 /PsJ, selected from the 20-krad treatment, was used for analysis of allelic relationship. In the allelic test, semidwarf mutant SM-268/PsJ was

Mugiono, National Atomic Energy Agency, Jakarta, Indonesia

We irradiated seeds of variety Seratus Malam with different doses of gamma rays (10, 20, 30, and 40 krad) in 1983. The M 2 generation plants were selected for semidwarf stature, and from 50,000 M 2 plants, 130 semidwarf mutants were

crossed with IR36. However, in the F 3 an early maturity line Obs-1647/PsJ was selected and tested for yield potential in the F 10 generation. The agronomic characters of Obs-1647/PsJ and the mother varieties are in Table 1.

Based on yield trials at 27 locations during 1992-95,Obs-1647/PsJ showed a higher yield potential at several loca-

Table 1. Agronomic characters of Obs-1647/PsJ (Cilosari) and mother varieties IR36 and SM-268/PsJ.

Parent 1 Parent 2 Derived line

(mutant) (Cilosari) Character SM-268/PsJ IR36 Obs1647/PsJ

Plant height (cm) Maturity (d) Productive tillers (no.) 1,000 grain weight (g) Amylose content (%) Yield (t ha -1 ) Cooking and eating quality Resistance to BPH biotypes 1 and 2 Resistant to bacterial leaf blight

60-65 110-115 5-7 15-17 22-23 2.0-2.5 Not good Susceptible Susceptible

70-80 110-120 14-19 23-25 24-25 4.0-4.5 Medium Resistant Resistant

110-125 110-120 10-15 26-27 20.5-21.0 5.0-6.5 Good Resistant Resistant

Table 2. Mean yield of Cilosari in yield trials at 27 locations. 1992-95. a

1992-93 1993 1993-94 1994-95 wet season dry season wet season wet season

Cilosari IR64 Cilosari IR64 Cilosari IR64 Cilosarl IR64 Location

Madiun Lamongan Ponorogo Bekasi Tulungagung Probolinggo West Sumatera Yogyakarta Banyuwangi Jombang Ponorogo Serang Temanggung Ogankomering North Aceh Central Lampung Bandung South Sulawesi South Lampung Bandung West Aceh lndragiri Hilir Tanjung Jabung Kerinci Bengkalis

5.70 a 5.20 a 5.23 a 5.17 a 8.40 a 8.30 a 7.30 a 5.90 b 8.10 a 7.80 a 7.10 a 5.60 b 4.90 a 6.40 b

5.99 a 4.37 a 4.58 a 4.20 a 5.01 a 5.33 a 5.45 a 5.94 a 3.69 a 3.63 a 4.92 a 5.38 a

6.47 a 6.43 a 6.55 a 5.73 a 8.46 a 8.02 a

10.14 a 9.68 a 5.82 a 5.07 a 7.04 a 5.50 b

9.97 a 9.68 a 3.63 a 2.65 b 4.71 a 2.42 b 6.65 a 4.45 b 6.83 a 5.67 b 4.76 a 2.55 b

a ln a row in the same location, means followed by the same letter are not significantly different by HSD test at the 5% level.

tions when compared with IR64 (Table 2). The Ministry of Agriculture in Indo- nesia released this line in July 1996 as Cilosari, a variety for irrigated areas.

FARO 44 and FARO 50: two irrigated lowland rice varieties for Nigeria

E.D. Imolehin, M. N. Ukwungwu, J. K. Kehinde, A. T. Maji, and J. A. Akinremi, National Cereals Research Institute, Badeggi; B. N. Singh and O. Oladimeji, West Africa Rice Development Association c/o International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria

Irrigated lowland rice is grown on around 10% of the 1.77 million ha planted to rice in Nigeria. In August 1996, the National Crop Variety Release Committee in Nigeria released two semidwarf varieties, FARO 44 and FARO 50, for this ecosystem. They are suitable for all the zones except southeastern Nigeria, where African rice gall midge (ARGM) is a major problem. Their detailed characteristics are shown in the table.

FARO 44 is the varietal name given to the line SI-692033. It was bred at Chiayi Agricultural Experiment

Agronomic characteristics of two lowland rice varieties.

Characteristic FARO 44 FARO 55

Designation Sipi 692033 ITA230 Cross Sipi 661044/ BG90-2 4 /

Sipi 651020 Tetep Days to 50% flowering 85 90 Plant height (cm) 105 110 Blast resistance a 3 1 ARGM a 9 9 RYMV a 9 9 Iron toxicity a 7 7 Leaf scald a 3 1 Brown rice length (mm) 6.9 7.3 Brown rice width (mm) 2.2 2.2 L/W 3.1 3.3 Grain type Long slender Long slender Chalkiness a 0 5 Gel temperature a 7 5 Amylose % 26.0 28.0 Husk color Straw Straw 1000-grain weight (g) 26.5 23.6 Av yield (t ha -1 ) 4.0 5.0 Yield potential (t ha -1 ) 8.0 10.0

a SES scale, IRRI (1996).

Vol. 22. No. 3. 21

- -

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

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

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

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

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

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

Station, Kaohsiung, Taiwan, introduced through International Rice Testing Program nurseries in 1981, and further evaluated by the International Network for Genetic Evaluation of Rice-Africa and in multilocational coordinated rice evaluation trials (CRET) in Nigeria. After 3 yr in CRET, the line was further evaluated in farmers' fields by the National Ac-

celerated Food Production Programme (NAFPP).

FARO 50 is a varietal name given to line ITA230. It was selected from the F 4 lines introduced from the Centro Internacional de Agricultura Tropical, Colombia. As line 6902, it was selected for yield potential and blast resistance at the International Institute of Tropical Agriculture, Ibadan. The line was

evaluated in CRET and NAFPP prior to its release.

Both FARO 44 and FARO 50 are resistant to leaf blast and leaf scald, but are susceptible to iron toxicity, ARGM, and rice yellow mottle virus. They have long, slender grains and high amylose content. Both are popular in irrigated rice areas of north and central zones of Nigeria.

Xingxiangyou 77, a high- yielding and fine-quality semi- aromatic hybrid rice

Zhou Kunlu and Liao Fuming, Hunan Hybrid Rice Research Center (HHRRC), Changsha 410125, Hunan, China

Xingxiangyou 77 was developed at HHRRC using aromatic cytoplasmic male sterile line Xingxiang A and nonaromatic restorer line Minghui 77. It was extensively tested and approved for release to farmers by the Hunan Provincial Crop Variety Release Com- mittee in February 1997. Xingxiang A, improved from the first aromatic CMS line Xiangxiang 2A, is another aromatic

CMS line developed by HHRRC. The new line has stable male sterility and better outcrossing characteristics than Xiangxiang 2A. Minghui 77, developed by the Sanming Agricultural Institute, Fujian, China, is a popular strong restorer line with good grain quality. The cross between these two parents was first made in 1993. In 1994, the hybrid was tested in the Hunan Rice Variety Multilocational Trial and yielded 6.9 t ha -1 on average at all five locations, 5.5% higher (significant at 5% level) than check Weiyou 64. In the same year, it gave a mean yield of 5.9 t ha -1 at six locations in the trial of new commercial fine-quality rice varieties of Hunan Province with a yield advan-

tage of 2.9% over check Xiangwanxian 1. Tested in the Hunan Rice Variety Regional Trials of 1995 and 1996, it gave a mean grain yield of 6.8 t ha -1 over 14 and 12 locations, respectively, with yields of 2.3% and 5.6% higher than those of check Weiyou 64 (Table 1). In the on-farm trials and demonstration plots, it generally yielded 6.8 to 7.7 t ha -1 when grown as late rice in a double-cropping system.

Most of the variety's grain quality characters met the 2nd class standards of fine-quality rice issued by the Chinese Ministry of Agriculture (Table 2). Furthermore, because its CMS line Xingxiang A is aromatic and its restorer line Minghui 77 is nonaromatic,

Table 1. Agronomic characters of Xingxiangyou 77. Hunan Rice Variety Regional Trial, China.

Hybrid Locations Hybrids Maturity Plant Spikelets Filled 1000-grain Grain

Year (no.) tested (d) height panicle -1 spikelets weight yield a

(no.) (cm) (no.) (%) (g) (t ha -1 )

Xingxiangyou 77 1995 14 10 114.0 99.1 108.7 69.2 27.4 1996 12 11 114.8 96.0 105.6 77.8 28.3

6.8 ns

1995 Weiyou 64 (check) 14 10 97.0 98.0 72.2 6.9 ns

114.0 1996 12

28.5 11

6.6 113.3 91.0 100.7 74.9 29.3 6.5

a ns = yields not significant by Duncan's SSR test (in 1995) or by Fisher's PLSD test (in 1996). The experiment used three replications.

Table 2. Grain quality performance of Xingxiangyou 77.

Hybrid/ standard testing

Institutes a

doing the

(year)

CNRRI (1995)

Xingxiangyou 77 HRRl (1995) HRRl

(1996)

CMA 1st class standard 2nd class

Brown rice (%)

81.6

81.0

81.0

>81 >79

Milled rice (%)

73.6

77.5

66.8

>74 >72

Head Kernel Chalky Gelatinization Gel Amylose Protein rice temperature consistency content content (%) Length L/W Rice Area (alkali (mm) (%) (%)

(mm) (%) (%) value)

58.4 7.1 3.1 46 50 6.8 62 24.0 12.2

56.0 7.2 3.1 61 26

61.0 7.1 3.0 58 26

>59 6.5-7.5 >3.0 <5 <5 >4 >60 17-22 >8 >54 5.6-6.5 2.5-3.0 <10 <10 >4 41-60 <25 >8

a CNRRI: Chinese National Rice Research Institute; HRRI: Hunan Rice Research Institute: CMA: Chinese Ministry of Agriculture.

22 IRRN 1997

Xingxiangyou 77 is considered a semi- aromatic hybrid rice. It produces only partially aromatic grains on each plant (owing to F 2 segregation for aromatic genes). Consumers prefer semi- aromatic rice to pure aromatic rice.

Using the 1-9 scales of the Standard evaluation system for rice, the hybrid scored 6 for leaf blast, 7 for neck blast, and 7 for bacterial leaf blight.

When planted as late rice in the double-cropping system in Hunan,

Xingxiangyou 77 matured in about 115 d (Table 1). It was about 98 cm tall with strong tillering ability. Its seed set was 75%) with a mean of 105-110 spikelets panicle -1 and a 1000-grain weight of 27-28 g.

New rice varieties for the rainfed lowlands of Cambodia

Makara, S. Sovith, P. K. Hel, Ministry of Agriculture, Forestry and Fisheries; E. L. Javier and G. S. Sidhu, Cambodia-IRRI-Australia Project (CIAP), Phnom Penh, Cambodia

The rainfed lowland rice ecosystem is highly diverse in Cambodia. Several niches exist within the ecosystem, each of which may require different rice varieties of early, medium, or late maturity.

The Varietal Recommendations Committee (VRC) of the Cambodian Department of Agronomy approved the release of three modern, photoperiod-insensitive, early-duration (less than 120 d) and three modern, photoperiod-insensitive, medium-duration (120-150 d) varieties selected by CIAP between 1990 and 1993. In 1995, the VRC approved the release of six pureline selections from traditional Cambodian varieties for cultivation in the rainfed lowland ecosystem.

The six selections originated from the traditional varieties Pram Bei Kuor (PPD679), Sambak Kraham (PPD597), Sraem Choab Chan (Germplasm B- 293), Changkom Ropeak (Germplasm 90B-528), Kantuy Touk (PPD156), and Sae Nang (Germplasm 90B-429). The VRC decided that all varieties released in Cambodia will be assigned continuous numbers following the letters CAR, which signify “Cambodia rice.” So these selections were named CAR1- CAR6, respectively.

In the early 1970s, Cambodia's rice germplasm collections were sent to IRRI headquarters in the Philippines for safekeeping. Many of these varieties were subsequently lost in Cambodia

because of the lack of cold storage facilities and the civil unrest in the 1970s. In the 1980s, the collections were returned to Prey Phdau Station at the government’s request. The source populations for CAR1, CAR2, and CAR5 belonged to these collections and could have been completely lost if they had not been conserved at IRRI’s International Rice Genebank. The source populations for the other varieties released were part of the CIAP

germplasm collection obtained through the joint efforts of the Department of Agronomy, provincial agriculture offices, nongovernment organizations, and CIAP.

On the basis of preliminary yield trials (PYT) and advanced yield trials (AYT) conducted for several years at multiple locations, CAR1 yielded 11%) more than the check Mahsuri while CAR2 and CAR3 yielded 18% more (Table 1). CAR4 has a yield advantage of

Vol. 22 No. 3 23

Table 1. Yield (t ha -1 ) of photoperiod-sensitive, traditional medium- and late-duration rice varieties and checks a

for rainfed lowland ecosystem in Cambodia.

Year Trlal b

1990 PYT (0, 2) 1991 PYT (1, 3) 1992 AYT (9, 6) 1993 AYT (9, 8) 1994 AYT (6, 10)

Mean % Increase over check

Medium-duration varieties

CAR 1 CAR 2 CAR 3 MS

3.3 3.8 3.8 3.2 3.0 3.3 3.3 2.8 3.2 3.4 3.3 2.9 3.0 3.1 3.3 2.6 3.1 3.3 3.3 2.8

11 18 18 0

Late-duration varieties

CAR 4 CAR 5 CAR 6 TS2

4.2 3.3 3.9 3.4 5.2 4.4 4.6 3.7 4.2 4.0 4.0 3.9 3.6 3.5 3.4 2.6 3.7 3.4 3.6 2.8 4.0 3.7 3.8 3.0

29 19 23 0

advanced yield trial. The first and second values in parentheses refer to the number of locations involved in medium-and late-

a Checks for medium- and late-duration trials are Mahsuri (MS) and Toul Samrong 2 (TS2). b PYT = preliminary yield trial, AYT =

duration trials, respectively.

Table 2. Date of 50% flowering, growth duration, and plant height of photoperiod-sensitive, traditional medium- and late-duration varieties and checks. 1993-94 wet seasons. Cambodia.

Date of 50% flowering

Medium-duration

CAR2 CAR1 4 Nov-3 Dec 13 Nov-1 Dec 160 (145-172) 166 (150-180) 127 (95-180)

7 Nov-9 Dec 22 Oct-10 Dece 162 (146-178) 165 (150-182) 126 (90-178) CAR3 1 Nov-3 Dec 7 Nov-26 Nov 156 (138-172) 162 (150-175) 122 (89-167)

Growth duration a (d) Height a (cm) Variety 1992-94

1993 1994 1993 1994

MS 9 Oct-4 Dec 8 Oct-15 Nov 150 (128-170) 142 (135-151) 113 (81-156) Sowing time 22 Jun-31 Jul 21 Jun-17 Jul 22 Jun-31 Jul 21 Jun-17 Jul

Late-duration CAR4 15 Nov-4 Dec 14 Nov-28 Nov 171 (162-182) 174 (160-186) 132 (93-161) CAR5 17 Nov-10 Dec 16 Nov-1 Dec 173 (162-182) 177 (166-190) 134 (93-184) CAR6 13 Nov-5 Dec 14 Nov-28 Nov 171 (161-183) 174 (161-187) 129 (94-183) TS2 25 Nov-12 Dec 18 Nov-6 Dec 182 (171-195) 182 (169-196) 125 (96-194) Sowing time 18 Jun-14 Jul 15 Jun-20 Jul 18 Jun-14 Jul 15 Jun-20 Jul

a The first value is the mean. Values in parentheses represent the range.

Integrated germplasm improvement—rainfed lowland

- - - -

-

-

29%; CAR5, 19%,, and CAR6, 23%, over acceptable. The raw milled rice CAR5, and CAR6 are late-duration check Toul Samrong 2. qualities of the six varieties were week of October (Table 2). CAR4,

sensitive. They can be sown between the second week of November. Their at least 90% for the other varieties. May and August and still flower at a

for CAR3 to 2.99 for CAR4 and CAR6. showed that the raw and cooked rice CAR2 can flower as early as the third length-breadth ratio ranging from 2.49 A sensory test using 94 evaluators the first week of November while have medium-sized grains, with the medium-duration varieties. CAR1 and CAR3 can flower as early as for the other varieties. All six varieties CAR3. In general, they are taller than CAR3 are medium-duration varieties. CAR1 and CAR2 and more than 95% longer than that of CAR1, CAR2, and given range of time. CAR1, CAR2, and Cooked rice acceptability was 87% for mean growth duration is about a week

The new varieties are photoperiod- acceptability for CAR3 was 75%. It was varieties. They can flower as early as

FARO 45 to FARO 49: two early- All varieties are ITA lines selected upland rice varieties for different maturing and three medium-

released in Nigeria maturing upland rice varieties

from the crosses made in IITA, Ibadan. agroecological zones in Nigeria. Their characteristics are shown in the table.

made in 1979. It involved parents such northwestern and northeastern zones, generation from a three-way cross FARO 45 is more suited to the FARO 45 is ITA 257 line, selected in F 4

E. D. Imolehin, M. N. Ukwungwu, J. K. Kehinde, A. T. Maji, J. A. Akinremi, National Cereals Research Institute, Badeggi; B. N. Singh and O. Oladimrji, West Africa Rice Development Association c/o International Institute of Tropical Agriculture, Ibadan, Nigeria

Upland rice is grown on 30% of the 1.77 million ha planted to rice in Nigeria. In August 1996, the National Crop Variety Release Committee released two early- maturing and three medium-maturing

while FARO 46 is recommended for all the five agroecological zones of the country. Both are harvested at around 100 d after seeding.

FARO 47 is recommended for the southeastern zone, and FARO 48 and FARO 49 are suitable for hydromorphic areas of the Niger, Benue, and Plateau states in central Nigeria and upland areas of southwestern Nigeria. These three varieties have durations of 115- 120 d.

as IRAT 13, Dourado Precoce, LAC 23, IET1444, OS 6, CP-SLO, and TN1. FARO 46 is ITA 150 line, selected in F 5 from a single cross made in 1976. It involved parents such as 63-83, ROK 1, SE363G, and Dourado Precoce. FARO 47 is ITA 117 line, selected in F 5 from a cross made in 1975. It involved parents such as 13A, CP-SLO, TN1, and OS 6. FARO 48 is ITA301 line, selected in F 8 from a three-way cross among IRAT13, Dourado Precoce, and Padipayak

Agronomic characteristics of two early- and three medium-maturing upland rice varieties. Ibadan, Nigeria.

FARO 45 FARO 46 FARO 47 FARO 48 FARO 49

Designation Line Cross

Year of hybridization Plant height (cm) Days to 50% flowering Blast resistance a

Drought tolerance a

Leaf scald a

Brown rice length (mm) Brown rice width (mm) Brown rice L/W Brown rice shape Chalkiness a

Gelatinization temperature a

Gel consistency a

Amylose (%) Husk color 1000 grain weight (g) Av grain yield (t ha -1 ) Yield potential (t ha -1 )

ITA257

IRAT13/Dourado Precoce/TOX490-1

TOX1011-4-1

1979 100

70 1 1 3 6.5 2.9 2.2

Medium bold 1 3 3

17.4

31.0 2.0 3.5

Golden

ITA150

63-83/Multiple parent#23 b

1975 110

75

TOX502-41-1-1

1 1 1 7.5 2.6 2.9

Long bold 1 5 5

22.5 Golden

33.5 2.0 3.0

ITA117 TOX356-1-1-1

1529-430-3/ TOX7-4-2-5-2

13A2-18-3-1-3/

1975 105 85

1 3 1 7.2 2.2 3.1

Long slender 1 5 5

19.5

26.5 Straw

2.5 3.5

ITA301

IRAT13/Dourado Precoce// Padipayak

1978 100

98 1 1 5 7.4 2.4 3.1

Long slender 5 5 5

16.4

29.5 2.5 3.5

TOX854-101-3-201-1-1-1

Straw

ITA315 TOX936-397-9-1-2 lR1529-430-3/ lguape Cateto

1979 100

90 1 1 7 7.0 2.7 2.6

9 3

Long bold

1 16.2

30.5 2.0 3.5

Straw

a SES scale (IRRI 1996). b Multiple parent #23: ROK1, SE 363G, and Dourado Precoce.

Integrated germplasm improvement—upland

24 IRRN 1997

The State Variety Release Committee, West Bengal, approved the release of two varieties, Saraswati (CN584-311- 10) and Jalaprabha for deepwater ecosystems (50-100 cm) in June 1996. Saraswati is a pedigree selection from the cross Pankaj/Patnai 23, done at RRS. It was evaluated as IET11271 in national trials during 1989-94 (Table 1). The pooled average yield across 36 locations was 50% more than national check Utkal Prabha. In national testing, it ranked fourth in the 1989 preliminary variety trial, eighth in the 1993 advanced variety trial-semideep water, and second in the 1994 advanced variety trial-semideep water, tested over 13 locations. The variety’s mean yield was 2.7 t ha -1 with yield potential of 4.6 t ha -1 . The All-India Rice Work- shop suggested it for use in the deepwater areas of Assam, West Bengal, Andhra Pradesh, Uttar Pradesh, and Orissa.

Saraswati is tall, photoperiod- sensitive, and flowers around the end of October. Its submergence tolerance is mainly through elongation, and it has very good kneeing ability. Panicles are well exserted with short, bold golden grains and purple apiculi. Kernels are about 5.5 × 2.6 mm. Hulling percentage is 78.5 and milling percentage is 68.5.

S. Mallik, B. K. Mandal, C. Kundu, S.K.B. Roy, B. Banerjee, S.K. Dutta, and S. D. Chatterjee, Rice Research Station (RRS), Chinsurah, 712102, West Bengal, India

Saraswati and Jalaprabha: two new deepwater rice varieties for eastern India

made in 1978. FARO 49 is ITA315 line,

The varieties are location-specific. have drought tolerance and escape in 1979. It involved parents such as they were evaluated in farmers’ fields. Nigeria. FARO 45 and FARO 46 also selected in F 6 from a single cross made superior performances in these trials, major problems affecting upland rice in

uplands of the humid forest zone. The early. CP-SLO, and Iguape Cateto. FARO 45 is not suited for the acidic drought damage because they mature Sigadis, TN1, Peta, Dee-geo-woo-gen,

All five varieties are resistant to leaf The lines were evaluated in multi- WARDA Lowland Rice Breeding Unit blast. FARO 45 and FARO 46 are locational coordinated rice evaluation at IITA, Ibadan, Nigeria, is producing resistant to leaf scald. These are the trials (CRET) in Nigeria. After 3 yr of breeder seed of all varieties.

Table 1. Performance of Saraswati in national trials in India. 1989-94.

Yield (t ha -1 ) Maximum Year Trial a /site water depth

Saraswati Utkal Prabha (cm)

1989 PVT5 Patna, Bihar 4.5 b 2.1 65 Pusa, Bihar 4.6 3.7 55 Karimganj, Assam 2.6 2.4 25 Pulla, Andhra Pradesh 4.3 2.6 80

1990 IVT-SDW Chinsurah, West Bengal Sabour, Bihar Ghagraghat, Uttar Pradesh Canning, West Bengal North Lakhimpur, Assam

1991 AVT-SDW Ranital, Orissa Chinsurah, West Bengal Karimganj, Assam Patna, Bihar Faizabad, Uttar Pradesh Ghagraghat, Uttar Pradesh

1992 AVT-SDW Pulla, Andhra Pradesh CRRI, Orissa Chinsurah, West Bengal Sabour, Bihar Karimganj, Assam

1993 AVT-SDW CRRI, Orissa Chinsurah, West Bengal Patna, Bihar Pusa, Bihar Sabour, Bihar Faizabad, Uttar Pradesh Karimganj, Assam

1994 AVT-SDW Ranital, Orissa Chinsurah, West Bengal Gosaba, West Bengal Patna, Bihar Sabour, Bihar Masodha, Uttar Pradesh Ghagraghat, Uttar Pradesh Canning, West Bengal Karimganj, Assam

1.8 b

3.7 2.0 b

4.2 b

3.5

2.1 a

3.6 b

3.2 1.9 1.1 2.0

1.5 1.7 1.2 b

2.4 4.1 b

1.6 b

4.1 b

2.9 1.10 2.7 b

3.1 b

3.9

2.5 b

2.5 b

3.5 1.7 2.3 b

3.2 b

1.7 2.9 2.6 b

Nil 3.2 1.2 Nil 3.3

1.8 2.3 2.3 1.5 0.5 1.3

1.4 1.4 0.2 2.4 3.5

70 na c

na na na

na 65 na na na na

60 100

55 45 25

0.7 1.6 2.2 Nil 1.9 2.3 3.8

1.3 1.1 2.9 1.5 0.7 1.8 1.5 2.6 2.1

75 na

75 na

30 na

31

50 50 50 na na 60 50 na na

a PVT 5 = preliminary variety trial 5, IVT-SDW = initial variety trial-semideepwater, AVT-SDW = advanced variety trial-semideepwater. b Significantly superior to national check at the 5% level. c na = not available.

Integrated germplasm improvement—flood-prone

Vol. 22, No.3 25

Table 2. Performance of Jalaprabha in national trials in India. 1989-94.

Year Trial a /site Yield (t ha -1 ) Maximum

Jalaprabha Jalamagna depth (cm) water

1989 PVT6 Chinsurah, West Bengal North Lakhimpur, Assam

1990 IVT-DW Pusa, Bihar North Lakhimpur, Assam

1991 AVT-DW Chinsurah, West Bengal Pusa, Bihar

1992 AVT-DW Motto, Orissa Ghagraghat, Uttar Pradesh

1993 AVT-DW Chinsurah, West Bengal

1994 AVT-DW Chinsurah, West Bengal Pusa, Bihar Motto, Orissa

1.9 b

2.1 b

2.5 4.1 b

1.8 b

3.4 b

2.4 3.7

1.6 b

4.0 b

3.8 b

2.8 b

nil 1.2

2.4 2.6

0.5 2.2

1.7 2.7

0.6

0.9 2.5 2.4

65 110

na c

na

95 na

125 141

100

80 na na

a PVT 6 = preliminary variety trial 6, IVT-DW = initial variety trial-deepwater, AVT-DW = advanced variety trial-deepwater. b Significantly superior to national check at the 5% level. c na = not available.

Both alkali value (6.5) and amylose

by IRRI and evaluated as IET11870 in Saraswati has resistance to blast, selection from a composite cross sent content (30.0) are high. Jalaprabha was developed by pedigree

sheath blight, sheath rot, yellow stem the national varietal testing program borer, and whitebacked planthopper. for several years (Table 2). The pooled

averages across 12 locations yielded 73% more than check Jalamagna. The variety's yield potential is 4.1 t ha -1 . In national testing, it ranked second in the 1990 initial variety trial-deepwater, first in the 1991 advanced variety trial- deepwater, third in the 1993 advanced trial-deepwater, and first in the 1994 advanced variety trial-deepwater. The All-India Rice Workshop in 1995 recommended it for the eastern Indian states of West Bengal, Orissa, Bihar, and Uttar Pradesh.

Jalaprabha is tall, photoperiod- sensitive, and flowers around the first week of November. Its submergence tolerance is mainly through elongation, and it has very good kneeing ability. Panicles are compact and well exserted with short, bold, golden grains. Kernels are about 5.6 × 2.4 mm. Hulling percentage is 78.8 and milling percentage is 64.1. Both alkali value (7.0) and amylose content (29.2) are high. Seed dormancy is about 3 mo.

It has tolerance for yellow stem borer, leaffolder, sheath rot, sheath blight, blast, and false smut.

Nucleus and breeder seed production of thermosensitive genic male sterile lines

S. S. Virmani, B. C. Viraktamath, and M. T. Lopez, IRRI

Thermosensitive genic male sterile (TGMS) lines are suitable for developing two-line hybrids in the tropics because temperature variations are found in different seasons and/or locations for maintaining effective sterility and fertility. Research efforts by IRRI and national agricultural research systems (NARS) have resulted in identifying many TGMS lines from four to five sources that can be deployed for developing two-line hybrids. Production of good-quality

pure seed of TGMS lines is a prere- quisite for successful use of these lines.

Experience in China has indicated that TGMS lines multiplied conven- tionally by bulking their seeds at a fertility-inducing temperature may tend to segregate for their critical sterility /fertility points. Seed obtained from such lines may not be pure. These lines, when used to produce two-line hybrid seeds, could be a mixture of selfed and hybrid seeds, resulting in unstable hybrids. Nucleus and breeder seed production strategies should, therefore, aim to meet the dual objectives of maintaining complete male sterility during hybrid seed production and higher seed set during TGMS multiplication. We describe here a simple method of producing nucleus

and breeder seed of TGMS lines under field conditions.

TGMS multiplication and hybrid seed production must be identified based on weather data and the behavior of selected TGMS lines. For example, at IRRI, flowering of TGMS lines in January and February induces fertility and is ideal for multiplication, whereas flowering from mid April to May induces complete male sterility, a condition necessary for hybrid seed production. The proposed method shown in the figure will produce nucleus and breeder seed of TGMS lines.

Nucleus seed production of a TGMS line is initiated in a fertility-inducing environment. Seeding of TGMS lines is

Seasons / locations suitable for

Seed technology

26 IRRN 1997

Procedure for nucleus and breeder seed production of TGMS lines.

arranged so that the sensitive stage occurs when the temperature is favorable for higher seed set. At flowering, about 100 typical plants are selected from the population of a TGMS line and their panicles are bagged. The selection process is completed within a week. After harvest, selected plants are scored for spikelet fertility (based on the main panicle) and 50 plants with higher spikelet fertility are selected.

grown in the sterility-inducing environment. About 30 seeds are taken from each of the selected plants to grow single row progenies and the remaining seed is stored carefully. Progenies that are uniform and completely male sterile are marked. The balance seeds of such selected progenies (stored earlier) are bulked to form the nucleus seed (see figure).

Nucleus seed is used to produce breeder seed under strict isolation. Breeder seed is produced in the fertility- inducing environment. The whole process of producing nucleus seed is repeated from the breeder seed plot. Fresh breeder seed should be used by seed production agencies to produce foundation seed of TGMS lines. The latter should be used to produce hybrid seeds.

Progenies of the selected plants are

Crop and resource management

Response of promising rice genotypes to N levels in rainfed lowlands

S. K. Singh, Central Rainfed Lowland Rice Research Station (CRLRRS), IIT Campus, Kharagpur 721302, West Bengal, India

Rainfed lowlands in India constitute about 17 million ha, which is about 40% of the total rice area. Rice varieties selected for their nutrient require-

ments, particularly N, have great relevance for boosting overall production of rainfed lowland rice in India.

The performances of genotypes IET12199, IET10664, IET8655, IET12777, and IET5914 were compared with that of local check Gayatri at three N levels (0, 40, and 80 kg ha -1 ).

The soil was sandy clay loam (Haplustalf), with a pH of 5.6, 0.40%, organic C, and 230 kg available N ha -1

(Kjeldahl method), 17 kg available P

ha -1 (NH 4 F extraction), and 280 kg available K ha -1 (NH 4 OAc extraction). The experiment was laid out in a split- plot design at CRLRRS with the genotypes in the main plot and N in the subplots with four replications.

Forty-five-day-old seedlings of different genotypes were transplanted during the first week of August. The recommended doses of 17.6 kg P ha -1

and 16.6 kg K ha -1 , along with one-third of the N according to the treatment,

Fertilizer management — inorganic sources

Vol. 22, No. 3 27

Table 1. Yield, yield attributes, N uptake, and agronomic N use efficiency of rice genotypes at different N levels. CRLRRS, Kharagpur, West Bengal, India. 1994 and 1995 WS.

Grain Panicles Panicle yield m -2

N uptake Agronomic N use weight

(t ha -1 ) (no.) (g) efflciency

(kg grain kg -1 N) Treatment (kg ha -1 )

N level (kg ha -1 ) 0

40 80

IET12199 Genotype

IET10664 IET8655 IET12777 IET5914 Gayatri

LSD (0.05)

LSD (0.05)

2.1 3.1 3.3 0.2

2.9 2.9 2.2 2.2 3.3 3.4 0.7

217 235 247

3.47

228 230 227 222 235 255

13

2.31 2.56 2.70 0.18

2.47 2.48 2.42 2.27 2.70 2.80 ns

45.9 70.2 24.0 90.7 15.1

3.15

62.2 67.3 53.1 49.5 88.4 93.1 5.97

Table 2. Interaction effect of genotype and N application on yield, yield attributes, N uptake, and agronomic N use efficiency. CRLRRS, Kharagpur, West Bengal, India. 1994 and 1995 WS.

N level Grain Panicles Panicle N uptake Agronomic N use

(t ha -1 ) (no.) (g) (kg grain kg -1 N) Variety (kg ha -1 ) yield m -2 weight (kg ha -1 ) efficiency

IET12199

IET10664

IET8655

IET12777

IET5914

Gayatrl

LSD (0.05) Between genotypes Between N levels Varietty × N level

0 2.2 212 2.31 41.4 40 3.0 230 2.47 63.3 80 3.4 242 2.64

0 81.8

2.2 214 2.32 44.8 40 3.1 232 2.48 68.5 80 3.4 244 2.65 88.6

0 1.5 211 2.20 35.4 40 2.5 229 2.45 54.1 80 2.6 241 2.62 69.9

0 1.4 206 1.81 32.9 40 2.5 224 2.42 50.4 80 2.6 236 2.59 65.1

0 2.5 218 2.56 58.8 40 3.5 237 2.73 89.9 80 3.8 249 2.82 116.3

0 2.7 239 2.68 61.9 40 3.7 257 2.85 94.8 80 4.0 269 2.88 122.4

0.654 12.60 ns 5.97 0.182 3.47 0.188 3.15 ns ns ns 7.71

20.0 15.0

22.0 14.8

24.5 13.8

28.5 15.5

25.0 16.3

24.5 15.6

were applied at transplanting. The remaining two-thirds of the N was applied in two equal splits at maximum tillering and panicle initiation.

Grain yield and N uptake increased with each increment of N up to 80 kg ha -1 , which registered the maximun yield as well as N uptake (Table 1). Grain yield was observed to be closely correlated with total N uptake (r=0.899). Increase in grain yield occurred mainly through the contribu- tion of number of panicles m -2 . Weight of panicle increased consistently up to 80 kg N ha -1 , but agronomic efficiency decreased from 24.0 to 15.1 kg grain kg -1

N at 40 and 80 kg N ha -1 , respectively. Genotype Gayatri recorded signifi-

cantly higher yield and N uptake than other genotypes but remained on a par with genotype IET5419. Most of the IET varieties had significantly lower N uptake than the check variety because of less N content in the plant sample and also because of total dry matter production. Yield and yield components also followed similar yield responses for different genotypes. Agronomic N use efficiency was higher in IET5914 and Gayatri than in other genotypes at 80 kg ha -1 . The gains may be attributed to the 84% higher yield recorded over that of the control (Table 2).

For rainfed lowland rice, none of the new genotypes tested outperformed the check variety Gayatri for high N use efficiency.

Performance of Azolla hybrids in lowland rice culture

G. Gopalaswamy and S. Kannaiyan, Agricultural Microbiology Department, Tamil Nadu Agricultural University, Coimbatore 641003, Tamil Nadu, India

Field experiments were conducted during the 1993 and 1994 dry seasons (June-September) to compare the effect of inoculation of Azolla hybrids and fertilizer N on rice yield. The experi-

ment was laid out in a randomized block design with three replications. The test soil was silty clay with a pH of 6.4, EC 0.45 dS m -1 , organic C 0.57%, 30.20 mol kg -1 CEC, 320 kg available N ha -1 , 24.9 kg P ha -1 , and 273.9 kg K ha -1 . ADT36 rice seedlings were transplanted in 1.5-m 2 plots with 15- × 10-cm spacing. Superphosphate and potash as muriate of potash at 50 kg ha -1 were applied as a basal dose. Nitrogen at 75 kg ha -1 was applied as urea super granules (USG) alone and with Azolla.

USG was applied at 10 cm deep at 7 d after transplanting in between four hills of alternate rows, and prilled urea (PU) alone was applied in four split doses (40, 20, 20, and 20%) at basal, tillering, panicle initiation, and flowering stages for comparing with USG. Azolla hybrids AH-C1 ( A. microphylla 4018 /A. microphylla 4028 (V3)), AH-C2 ( A. microphylla 4018 /A. microphylla 4028 (V4)), and AH-C3 (strain of A. microphylla from China), and wild type A. microphylla (from Galapagos Islands) were

Fertilizer management—organic sources

28 IRRN 1997

-

- - - - - - -

-

-

-

-

-

-

Table 1. Biomass production and nutrient content of Azolla hybrids.

Biomass (t ha -1 ) a Cumulative N P K Treatment biomass (%) (%) (%)

30 DAT 50 DAT (t ha -1 )

Control AH-C1 7.68 1.36 9.04 4.18 0.88 1.96 AH-C2 9.86 1.96 11.82 4.95 0.90 2.10 AH-C3 7.46 1.24 8.70 3.86 0.82 1.34 A. microphylla 6.68 1.16 7.84 3.26 0.70 1.16 AH-C1 + USG (75 kg N ha -1 ) 11.98 1.92 13.90 AH-C2 + USG (75 kg N ha -1 ) 12.46 2.64 15.10 AH-C3 + USG (75 kg N ha -1 ) 10.64 1.74 12.38 A. microphylla + USG (75 kg N ha -1 ) 9.68 1.62 11.30 USG (75 kg N ha -1 ) PU (75 kg N ha -1 )

CD 3.19 0.70 0.34 0.17 0.15

a Mean of two seasons.

Table 2. Effect of inoculation of Azolla hybrids and USG application on grain and straw yield of ADT36. Tamil Nadu, India. a

Grain yield (t ha -1 ) Straw yield (t ha -1 )

Treatment 1993 %increase 1994 %increase 1993 % increase 1994 % increase dry over dry over dry over dry over

season control season control season control season control

AH-C1 6.1 44.1 5.1 42.4 7.8 58.2 6.4 41.5 AH-C2 6.6 53.8 6.1 59.9 7.5 53.3 7.5 65.9 AH-C3 5.5 28.2 5.2 36.6 6.2 26.6 6.4 18.9 A. microphylla 6.0 41.0 4.3 13.4 6.6 33.3 AH-C1+USG 7.4

5.4 19.6 64.1 6.2 63.4 8.1 64.4 7.8 73.2

AH-C2+USG 9.0 110.3 7.3 91.9 10.1 104.4 9.9 119.6 AH-C3+USG 6.6 53.8 5.7 51.3 7.0 42.6 6.8 51.2 A. microphylla + USG 7.9 84.6 5.3 39.5 8.3 68.9 6.7 48.8

USG 7.5 76.9 5.2 36.6 8.5 73.3 6.5 43.9 PU 6.3 48.7 4.5 19.1 7.2 47.1 5.6 24.6 Control 4.2 - 3.8

SE 1.1 0.5 4.9 4.5 1.1

CD 0.6

2.2 1.2 2.2 1.4

a Av of three replications.

inoculated at 500 kg ha -1 on a fresh

and the control for two consecutive dry computed as detailed below. higher grain and straw yield than PU the net weight recorded, and biomass

The USG application resulted in was harvested, the moisture drained, planting was about 15 t ha -1 . entire Azolla mass floating in each plot porated at 30 d and 50 d after trans- plots 30 d after transplanting. The cumulative Azolla biomass incor- Azolla biomass was assessed in 1.5-m 2 Azolla cultures inoculated (Table 1). The weight basis at 10 dafter transplanting. on the growth rate of the different

After biomass was determined, seasons. The lower efficiency in PU Azolla cultures were spread uniformly treatments might be attributed to a N in each plot under saturated condi- loss mechanism. Inoculation of Azolla tions. Nearly 5% of the Azolla was left hybrids and a wild culture of A. micro- unincorporated after the first incor- phylla with and without fertilizer N at poration; this material was allowed to 75 kg N ha -1 as USG resulted in signifi- multiply up to 50 d after transplanting cantly higher grain and straw yield in and then the biomass was computed. ADT36 than in the uninoculated Azolla biomass incorporated was in the

hybrid AH-C2 with USG recorded the at 50 d after transplanting, depending the Azolla hybrids, incorporating Azolla range of 9-12 t ha -1 at 30 d and 2-3 t ha -1 unfertilized control (Table 2). Among

largest grain and straw yield for ADT36 in both seasons compared with all other Azolla cultures.

These results indicate that AH-C2 has higher N 2 -fixing ability and higher biomass production than other Azolla hybrids. Inoculation of Azolla hybrids coupled with USG deep placement further increased the grain and straw yield of ADT36 compared with A. microphylla. Results indicate that the increased N was attributed to Azolla hybrids as well as to the efficiency of USG.

Influence of sowing time on biomass production and seed yield of three green manure crops

L. Thomas and S. P. Palaniappan, Agronomy Department, Tamil Nadu Agricultural University, Coimbatore 641003, India

Sensitivity of some leguminous green manure species to photoperiod is a major constraint to increased biomass and seed production. We studied the influence of time of sowing on biomass production and seed production of three green manure crops, Crotalaria juncea (sunn hemp), Phaseolus trilobus (Pillipesara), and Stizolobium deeringia- num (velvet bean).

Pillipesara and sunn hemp are popular green manure crops in India suited for both upland and lowland conditions. Velvet bean is a fodder legume well adapted to areas of low rainfall and poor soil fertility.

Sowing was done on the 10th of every month from Oct 1993 to Sep 1994. The experiment was conducted under irrigated upland conditions. The soil was sandy loam with pH of 7.5, EC 0.5 dS m -1 , 196 kg available N ha -1 , 17.2 kg available P ha -1 , and 576 kg available K ha -1 . The spacing was 30 × 20 cm and all crops received 21.5 kg P ha -1 . The experiment was laid out in a randomized block design with three replications. The correlation between growing degree days (GDD) and

- - - - - -

- - - - - -

- -

Vol. 22, No. 3 29

biomass production at 60 DAS was determined, with GDD calculated as

where T max , T min , and T base (10ºC) are the maximum, minimum, and base temperature, respectively.

Biomass production and seed production were significantly influenced by the month of sowing. Velvet bean performed better in all the months compared with sunn hemp and Pillipesara. Both velvet bean and sunn hemp produced maximum biomass when planted in June (see table). The shorter growth period and low temperature restricted vegetative growth, and thus biomass production was the lowest in the winter months. All crops flowered earlier when sown in September. Velvet bean took only 50 d to reach 50% flowering when sowed in October-November, but the crop took 32-34 d longer when sowed in May-July (see table).

All crops produced the most seed when sowed in February because of more solar radiation and greater photosynthetic activity during this period. The crops performed better in kharif (monsoon) than in rabi (winter). The correlation between GDD and biomass production was highly significant in velvet bean at 60 DAS (see figure). AGDD greater than 1000 is more favorable for biomass production. When GDD is less than 900, biomass production decreased.

Vermicompost: a potential supplement to nitrogenous fertilizer in rice nutrition

R. Rani and O. P. Srivastava, Soil Science and Agricultural Chemistry Department, Institute of Agricultural Sciences, Banaras Hindu University Varanasi 221005, Uttar Pradesh, India

Integrated use of chemical and organic fertilizer is important to sustain a higher level of soil fertility and productivity. Some species of earthworms—

Peionyx excavatus, Perionyx sansibarius, Drazwida willsi, and Dichopster bolaui- are efficient users of organic wastes. They convert these wastes into good- quality manure in 45 d rather than 4-5 mo with ordinary composting. Nutri- ent content of ordinary compost ranges from 0.5 to 1.0% N, 0.17 to 0.34%) P, and 0.66 to 1.2% K. Vermicompost (VC) used in this experiment contained 1.347% N, 1.12% P, and 1.06% K.

A pot experiment was conducted using a randomized complete block

design with four replications to study the effect of different combinations of VC and urea fertilizer on yield and N utilization of rice (Saket 4). Experi- mental soil has pH 7.8, EC 0.165 dS m -1 , CEC 11.25 meq 100 g -1 soil, organic carbon 0.56%, and available amounts of 260 kg N ha -1 , 9.17 kg P ha -1 , and 130 kg K ha -1 .

Earthen pots were filled with 9 kg soil and 30-d-old seedlings were transplanted. Nitrogen, P 2 O 5 , and K 2 O were applied at the rate of 60, 30, and 30

Correlation between growing degree days and biomass production in velvet bean at 60 DAS.

30 IRRN 1997

Effect of sowing time on biomass production, days to 50% flowering, and seed yield. Coimbatore, India. 1993- 94.

Month Biomass (t ha -1 ) 60 DAS of

Days to 50% flowering Seed yield (kg ha -1 )

sowing Pillipesara Sunn hemp Velvet Pillipesara Sunn hemp Velvet Pillipesara Sunn hemp Velvet bean bean bean

Oct 1993 4.9 6.2 12.3 45.0 48.6 50.3 346 403 1421 Nov 1993 4.4 Dec 1993 4.9

6.9 12.0 46.7 48.3 50.7 291 388 1306

Jan 1994 5.8 5.2 11.0 46.0 47.6 63.3 310 6.5 12.8 44.3

462 1317 48.7 61.7 376

Feb 1994 6.0 565 1406

8.0 15.1 44.3 49.7 80.3 381 Mar 1994 5.0

713 1560 8.0 14.6 45.7 47.3 81.7 352

Apr 1994 4.7 611 1549

9.0 14.1 45.0 49.3 80.7 349 May 1994 5.0

410 1530 9.3 13.4 48.0 49.0 82.0 312

Jun 1994 4.3 367 1517

9.8 15.6 47.0 45.7 84.3 343 Jul 1994 4.6

662 1510

Aug 1994 3.5 7.5 15.0 47.0 47.3 63.6 311 546 1457 7.0 13.3 46.0

Sep 1994 3.9 49.3 63.6 311 546 1457

5.8 12.1 36.3 36.0 59.3 285 361 1294

SE 0.1 0.1 0.4 0.7 0.7 0.6 6.0 17.7 0.3 0.2 0.8 1.5 1.6 1.2 12.6 36.7 15.4 CD

7.4

ppm. Abasal dose of one-third N and a full dose of P and K were applied at the time of transplanting and the remaining two-thirds applied in two split doses after 20 and 40 d after transplanting (DAT).

effective panicles (at 55 DAT), plant height (at 55 DAT), and grain yield (g pot -1 ) was observed with the integrated treatment combination (T2) vs the full dose of fertilizer alone (Tl). Treatment T2 (two-thirds N through fertilizer + one-third N through VC) was on a par with T3 (three-fourths N through fertilizer + one-fourth N through VC) (Table 1). A significant increase in N uptake was also found with treatment T2.

in soil along with organic manure, the availability of N in the form of ammo- niacal N continued to be higher for a longer period (Table 2), showing better compatibility and efficiency of combined organic and inorganic sources. Agronomic efficiency in terms of increase in grain yield (g) per gram of

A significant increase in number of

When inorganic fertilizer was added

Table 1. Effect of different combinations of VC and fertilizer N on rice. Uttar Pradesh, India. 1994 wet season.

Effective Plant Grain Straw N in N in N Treatment panicles (no.) height yield yield straw grain uptake

(55 DAT) (cm) (g pot -1 ) (g pot -1 ) (%) (%) (g pot -1 ) (55 DAT)

T0 Control 7.4 51.0 6.5 9.8 0.42 0.85 0.10 T1 Full dose N 20.0 57.6 16.1 24.7 0.61 1.12 0.34

T2 2/3 N (fertilizer) + 24.6 62.4 18.6 26.2 0.65 1.19 0.38

T3 3/4 N (fertilizer) + 23.1 61.3 17.8 27.6 0.63 1.16 0.38

through fertilizer

1/3 N (VC)

1/4 N (VC)

LSD (0.05) 3.1 3.8 1.8 2.4 0.07 0.09 0.04

added N was 18 for fertilizer N and 21 for fertilizer N + VC, whereas the values of physiological efficiency in terms of increase in grain yield (g) per gram of increase in N uptake were 40 for fertilizer N and 44 for fertilizer N + VC.

Table 2. Release pattern of NH 4 + -N under waterlogged

conditions.

NH 4 + -N (ppm)

Treatment 7 d 14 d 21 d

Control 38.74 43.05 45.74 100 ppm N through 118.75 123.10 125.73

Combined application of inorganic 100 ppm N through VC 72.65 106.48 119.07

(NH 4 ) 2 SO 4

fertilizer (two-thirds N) and VC (one- third N) is promising for better ferti-

75 ppm N through 124.62 130.49 135.61

(NH 4 ) 2 SO 4 + 50 ppm recommendations, the performance of

N through VC lizer management. Before making (NH 4 ) 2 SO 4 + 25 ppm

50 ppm N through 122.75 129.01 136.61

these combinations must be evaluated N through VC

in farmers’ fields. 25 ppm N through 96.62 118.61 128.02 (NH 4 ) 2 SO 4 + 75 ppm N through VC

Two Myanma isolates of rice tungro bacilliform virus belong to the Southeast Asian strain

A. Druka, John Innes Centre (JIC), Virus Research Department, Colney, Norwich NR4 7UH, United Kingdom; Thane Htay and Aung Baw, Plant Protection Division, Myanmar Agricultural Service, Bayintnaung Road, West Jyogone, Insein, Yangon, Myanmar; and Roger Hull, JIC

Rice tungro is one of the most devastating rice diseases in South and Southeast Asia. It is caused by two viruses, rice tungro bacilliform virus (RTBV) and rice tungro spherical virus (RTSV). RTBV is responsible for symptom development. Its trans- mission by leafhopper depends on RTSV which, by itself, does not cause marked symptoms.

Two strains of RTBV have been reported previously, one from the Indian subcontinent, the other from Southeast Asia. The nearest that two RTBV strains were found is Assam in India, Dhaka in Bangladesh (Indian strain), and central Thailand, a distance of about 1500 km. These two regions are not separated by a rice-free area; Myanmar produces considerable rice. Although tungro has been suspected to occur in Myanmar, it has not been identified there. We were interested in seeing which RTBV strain can be found in Myanmar.

Samples with tungro symptoms were collected from the fields around Yangon (Baular, Hlegu, Central Rice Model Farm, Tookying) and around Mandalay (Pathenlay, Amarapura, and

Kankank). The quick assay for differentiation of strains is by polymerase chain reaction (PCR), around a 64-bp deletion, which is characteristic for the Indian strain. Degenerate primer sequences used for PCR are as follows: direct 5'- GAASAAGTACCATGACCATGAATACN (position 7743-7763 in RTBV genome) and reverse 5'- CACCCCGGGKRKWNGCTCTGATACCA (position 17-1 in RTBV genome). The ambiguities are K = G or T, M = A or C, R = A or G, S = C or G, and W = A or T. PCR results have shown that samples collected near Mandalay (Amarapura) and Yangon (Baular) are infected with RTBV; we were not able to detect RTBV in other samples. The size of the PCR products is 280 bp, which indicates no

Vol. 22, No. 3 31

Integrated pest management—diseases

deletion and that the Myanma RTBV isolates belong to the Southeast Asian strain.

PCR products of both isolates were sequenced directly using the same PCR primers. Nucleotide sequences were compared with other RTBV isolates (see figure). Only 3 positions (7765, 7768, and 7855), which represent only 1.5% of the region sequenced, of both isolates, were different from the published sequence of the Philippine isolate. The Indian isolate differs significantly from other Southeast Asian isolates, the homology being less than 80%.The Baular isolate has a transition of T (C at position 7853 and a deletion at position 7956, a structure that differentiates it from the Amara- pura and other isolates. Ambiguities found at positions 7858, 7870, 7921, 7945, and 7949 may reflect the level of variation of the virus within the isolate. This information is only found if PCR products of viral DNA are sequenced, because cloning would result in selection of only one variant per clone.

These results demonstrate that tungro is present in Myanmar. The symptoms were characteristic of the disease and occurred in patches in the fields. The results also support the versatility of this PCR approach in the identification of RTBV itself and the strain of the virus.

Hinosan (0.05%): an ecofriendly fungicide for managing rice sheath blight

M. S. Ali and A. K. Pathak, Regional Agricultural Research Station, Titabar 785630, Assam, India

Sheath blight (ShB) is a major fungal disease of rice in northeastern India. There are no ShB-resistant varieties for that region, so chemical management is used. Recently, more attention has been paid to chemicals that would not have a negative impact on microorganisms endogenous to the rice crop ecosystem.

In 1994 and 1995, we screened fungicides known to be effective against ShB

Nucleotide sequence comparison across the positions 7758-7982. Jll, JAP, and BEA are published sequences of RTBV isolates from the Philippines. IND is unpublished sequence of RTBV isolate from India (West Bengal), MY6 is the Amarapura isolate, and MY10 is the Baular isolate. White letters indicate differences found in isolates from Myanmar; bold letters are ambiguities expressed as IUB codes found in the sequences of PCR products.

but harmless to Trichoderma harzianum (Th), which is a well-known biocontrol agent of the causal agent of ShB, Rhizoctonia solani.

Seven fungicides were tested: Atemi 50 SL (cyproconazole), Bavistin 50 WP (carbendazim), Contaf (hexaconazole), Indofil M-45 (75% mancozeb), Hinosan (50%, edifenphos), Rhizolex 50 WP (tolelofoxmethyl), and Validacin 3L (validamycin). Treatments included recommended doses and half doses, which were tested in vitro and in vivo.

Results of the in vitro experiment indicated that, except for 0.05% Hinosan (8% inhibition), all fungicides showed inhibited Th within the range

of 31.8-92%. Hinosan (0.05%) showed no significant difference in inhibition and was equivalent to the control. When tested against the pathogen in vitro, all fungicides, including Hinosan (0.05%), showed significant inhibition compared with the untreated control (see table).

In the following winter rice seasons (Jun-Nov) of 1994 and 1995, two field trials were conducted on rainfed transplanted rice. Variety IR50 was selected and planted in two lines (20 × 15 cm) for each treatment with 2-m rows replicated three times.

fungicides, doses, and concentrations In the first trial (A), the same

32 IRRN 1997

Effect of fungicides (in vitro) on the growth of Trichoderma harzianum (Th) and Rhizoctonia solani (Rs) a and disease severity b of ShB.

Dose (%) % inhibition % inhibition Disease score Fungicide of Th (mean) of Rs (mean)

A (in vivo test I) B (in vivo test II)

Atemi 50 SL 0.2 77.1 cd 75.1 de 3.7 a 4.3 b Atemi 50 SL 0.1 31.8 b 49.0 c 5.0 bc 5.6 d Bavistin 50 WP 0.1 79.5 cd 71.1 d 3.7 a 4.3 b Bavistin 50 WP 0.05 65.1 c 53.4 c 4.3 ab 5.0 c Contaf 5 EC 0.2 92.0 d 88.8 f 3.0 a 3.6 a Contaf 5 EC 0.1 74.5 cd 71.7 d 4.3 ab 5.0 c lndofil M-45 0.25 69.1 c 75.1 de 4.3 ab 5.6 d lndofil M-45 0.125 48.4 bc 22.5 b 5.7 c 7.0 e Hinosan 50 EC 0.1 43.4 bc 84.1 ef 3.7 a 3.6 a Hinosan 50 EC 0.05 8.0 a 78.4 de 4.1 a 3.6 a Rhizolex 50 WP 0.2 77.2 cd 72.7 d 4.3 ab 3.6 a Rhizolex 50 WP 0.1 59.9 c 58.0 c 5.0 bc 5.0 c Validacin 3L 0.2 76.4 cd 87.6 f 3.0 a 3.6 a Validacin 3L 0.1 41.6 bc 54.5 c 5.0 bc 4.3 b Control 0 a 0 a 8.3 d 8.3 f Standard check 10 6 conidia mL -1 - 5.6 d

LSD (0.05) 15.82 7.17 0.39 0.51 CV (%) 15.34 9.1 11.56 14.7

a Means followed by a common letter are not significantly different at the 5% level. All data are means of three replicatlons. b Scored using the Standard evaluation system for rice scale 0-9. 1988.

were used and the plants were

appearance of the disease after 7 d of (0.1 and 0.05%) (see table). (0.2%), Bavistin (0.l%), and Hinosan intervals beginning from the first disease severity, followed by Atemi Five sprays were done at weekly Validacin (0.2%) showed the lowest artificially inoculated with R. solani inoculation. Contaf (0.2f%) and

In the second trial (B), the above treatments were used in combination with spray of the antagonist (Th) (106 conidia mL -1 ). The sprays were initiated with the respective fungicides as the disease appeared and after. Thus, out of five sprays, two sprays were made with the antagonist (see table). An additional treatment (standard check) was included in this test where all five sprays were done with the antagonist alone. In this second field test (B), Th alone suppressed the disease compared with the unprotected control. The lowest disease severity was recorded when Th was combined with Contaf (0.2%), Hinosan (0.1 and 0.05%), Rhizolex (0.2%), and Validacin (0.2%). The combined treatment of Hinosan (0.05%) with the biocontrol agent was found to be an exception and Hinosan (0.05%) in both the experiments controlled the disease. As the effect of Hinosan (0.05%) on Th had been documented in an earlier experiment, it is suggested for inclusion in the integrated pest management strategy to control ShB.

Record of Aspergillus terreus Thom. on rice grasshopper Hieroglyphus banian (F.) in India

R. Parthasarathy and P. Narayanasamy, Vector Pathology Laboratory, Entomology Department, Annamalai University, Annamalainagar 608002, Tamil Nadu, India

In a series of surveys on fungal diseases of rice insects in general and leaffolder in particular during the 1996 samba season (October through February) at Annamalainagar, 40% of the rice grasshopper ( Hieroglyphus banian [F.]) population was found to be infected with a fungal pathogen.

Nymphs and adults were diseased. The cadavers were dull and brownish yellow and were seen holding the rice culms with their legs, with the insects’ heads pointing toward the shoot tips (see figure). Abundant mycelial growth

Aspergillus terreus infecting the final nymphal instar of rice grasshopper.

was observed at the intersegmental regions of the thorax and the abdomen but not the head capsule. On continued exposure to sunlight, the cadavers dried and the fungal matrix withered off.

The cadavers were gathered from the field, surface-sterilized with 0.l% HgCl 2 for 1-2 min, and washed in sterile water. The organism was inoculated in Sabouraud maltose agar

(SMA) medium on petri plates and incubated at 25±1 °C for 15 d. The fungal colonies appeared 5 d after inoculation and the culture was initially pale yellow or bright yellow, and ultimately deep brown.

Pathogenicity testing of the fungus isolated was done by spraying its spore suspension (107 spores mL -1 ) over nymphs (second- and third-instar) and adults caged separately on IR50 rice plants grown in pots. The experiment was replicated three times using 10 insects replication -1 and three replications of a control receiving plain water spray. Mean mortality of the grasshoppers was recorded as 85%, in 4-5 d after spraying (see table). The fungus from the diseased cadavers was reisolated in SMA medium and the disease symptoms that developed were identical to those of the original cadavers gathered at the start. The

Vol. 22, No. 3 33

Integrated pest management — insects

- - -

Pathogenicity of Aspergillus terreus to the rice grasshopper.

Treatment Percent mortality due to mycosis

(X ± SD) a

Fungal spore suspension 85.4 ± 2.9** b

Water (control) 17.9 ± 6.9

a n = 3 replicates, 10 insects per replicate. b ** Signiflcantly different from control (P<0.01) by LSD test.

pathogenicity of the fungus thus was positive.

Aspergillus terreus Thom. So far The fungus was identified as

A. terreus has been known to be a soil fungus of the rice ecosystem and this is the first time it has been observed as an insect pathogen. The presence of the spores in the air of the rice ecosystem made it possible for the fungus to infect the rice grasshopper.

Fungus incidence peaked during the first half of Feb 1996 at Annamalai- nagar, which coincided with the maximum field population of the grasshopper (8-10 nymphs or adults net sweep -1 ). Nearly 6-8 diseased grasshoppers were detected on the leaf

lamina of rice plants at four locations randomly selected in the field. Climatic factors, such as 95% relative humidity and temperatures of 30 °C (max) and 24 °C (min), may have promoted the fungal infection.

Because of its field adaptability and high infectivity, A. terreus appears to be a potential candidate for developing a “mycoinsecticide” to biologically control grasshoppers in the future.

Institute in London identified the fungus.

The CAB International Mycological

Weed control practices for improving N use efficiency and productivity of flood-prone lowland rice

A. Ghosh and A. R. Sharma, Central Rice Research Institute, Cuttack 753006, India

Flood-prone lowland rice in eastern India is mostly dry-sown through broadcasting seeds on poorly prepared fields, a practice resulting in early weed infestation and inefficient use of basally applied fertilizers. Nitrogen use efficiency can be improved by controlling weeds through off-season tillage operations and adopting mechanical or chemical methods in the early stages.

We investigated the effects of tillage, weed control practices, and N fertilizer on the performance of rice during 1994 at Cuttack, India. A split-plot design,

Daily variations in flooding patterns in the field during the growing period of rice. Arrows indicate dates of sowing (s), germination (g), beushani/transplanting (t), and harvesting (h) of rice. Cuttack, India.

with tillage in main plots and combinations of weed control and N fertilizer in subplots, was used in three replications. The crop was grown in plots plowed in summer (Mar) and/or before sowing (late May) or transplanting (late July) (conventional tillage) with or without basal application of 40 kg N ha -1 . The crop was sown in dry soil on 1 Jun using 400 seeds m -2

at 20-cm row spacing, and sprayed with thiobencarb at 2 kg ha -1 within a week of sowing or subjected to beushani at 42 d after water accu- mulated in the field. Puddling was also included as an additional treatment for comparison, where 42-d-old seedlings were transplanted at 20- × 15-cm spacing using 3-4 seedlings hill -1 . Gayatri, a semidwarf, long-duration, photoperiod-sensitive rice variety, was used in the experiment.

Seeds germinated with the monsoon showers. Water started accumulating in the field from mid-July onward following regular monsoon showers (see figure). Water depth fluctuated widely, rising from 0 cm at 22 d after germination (DAG) to 54 cm at 36 DAG and receding to 0 cm at 52 DAG. The crops subjected to beushani or transplanted at 42 DAG at 12 cm water depth established well because the water level remained <10 cm up to 20 d thereafter. Peak flooding of 60 cm occurred in the late vegetative growth stages (78-84 DAG) and the crop

experienced extreme excess water stress for 10 d. Water level showed a declining trend from September and had receded completely by late October.

because of inadequate crop stand. Excessive flooding at both early and late vegetative stages resulted in restricted tiller production and greater mortality, leading to only 50-70 panicles m -2 at maturity (Table 1). The mean grain yield was significantly more with summer plowing than with conventional tillage because of the beneficial effect on the number and weight of panicles. Weed control efficiency from summer plowing was 56.3% compared with conventional tillage. The rice plants remained short and produced fewer panicles m -2 in the unweeded control than when weeds were controlled. Controlling weeds by chemical or mechanical methods improved grain yield significantly. The grain yield was highest with puddling, a practice that was on a par with the direct-sown crop under beushani but significantly higher than chemical weeding. Increase in yield was associated with a decrease in weed dry weight, which was lowest with puddling. The transplanted crop remained virtually weed-free throughout because growing weeds were incorporated thoroughly during puddling, and subsequent higher

Yield performance of rice was poor

Integrated pest management — weeds

34 IRRN 1997

Table 1. Mean effect of tillage, weed control practice, and N level on performance of rice and dry weight of weeds at harvest. Cuttack, India.

Plant height Panicles Panicle Grain Straw Weed Treatment at maturity m -2 weight yield yield dry weight

(cm) (no.) (g) (t ha -1 ) (t ha -1 ) (g m -2 )

Tillage Summer plowing Conventional tillage SE

Weed control practice No weeding Chemical weeding Beushani Puddling SE

N level (kg ha -1 ) 0 40 SE

115 116

1.2

113 120 114 115

1.3

110 121

0.9

67 58 2.4

52 64 62 72 2.5

55 70

1.8

2.79 2.57 0.049

2.47 2.74 2.73

0.046

2.56

0.033

2.78

2.81

2.78 3.12 67 1.98 2.86 142 0.055 0.085 3.9

1.73 2.33 235 2.33 3.03 105

2.77 3.48 35 0.062 0.095 3.5

2.12 2.41 93 2.63 3.58 116 0.044 0.067 2.4

2.68 3.14 43

Table 2. Interaction between tillage, weed control practice, and N level and effect on grain yield of rice (t ha -1 ). Cuttack, India.

Weed control practice

No Chemical Beushani Puddling Treatment Mean

weeding weeding

Tillage Summer plowing Conventional tillage

0 N level (kg ha -1 )

40 Mean

Tillage Weed control practice N level Tillage × weed control Weed control × N level

2.11 2.86 3.02 3.13 2.78 1.35 1.80 2.34 2.42 1.98

1.55 2.02 2.43 2.50 2.12 1.91 2.64 2.94 3.05 2.63 1.73 2.33 2.68 2.77

SE 0.055 0.062 0.044 0.126 0.126

water depth and fast canopy closure did not allow the weeds to come up. Thiobencarb did not effectively control broadleaf weeds (mainly jointvetch) and late emerging aquatic weeds. Applying 40 kg N ha -1 increased plant height and number and weight of panicles and led to significantly larger grain yields, despite increased weed biomass.

practices and tillage or N levels were significant for grain yield of rice (Table 2). Inadequate land preparation under conventional tillage resulted in profuse weed growth from the early stages, which greatly reduced yield in the unweeded control and chemical weeding treatment. The differences in yield between summer plowing and conventional tillage, however, narrowed under beushani and puddling because of a considerable increase in weed biomass. Basal fertiliza- tion with N encouraged weed growth in the early stages, suppressed the growth of rice plants, and thus did not benefit the crop under the unweeded control. The increase in yield from N was significant, however, when weeds were controlled by either cultural or chemical methods.

Interactions between weed control

On-farm water management studies in ricefields of north Bihar, India

U. K. Prasad, S. S. Singh, T. N. Prasad, and S. K. Jain, Agronomy Department, Rajendra Agricultural University, Pusa, Samastipur 848125, India

We studied the effects of applying improved water management technology during the wet season in canal- irrigated ricefields for 6 yr (1989-94) in the Jian minor canal of the Tirhut main canal in Gandak command, Bihar,

India. We irrigated rice to a depth of 7 cm 3 d after ponded water disappeared. This treatment was compared with the usual farmers’ practice of irrigating according to the availability of water from canals and rain. Farmers generally apply more than 10 cm irrigation water continuously, especially in the head of the minor canal. Six to 18 farms were used in the study each year, with an average field size of 0.4 ha (see table). Soil was silty loam. A stage level recorder at the opening of the minor canal and Parshall flume in each outlet were used to measure irrigation water used.

In the study fields (improved practices), semitall improved rice variety Rajshree with maturity period of 145 d was tested against local photoperiod-sensitive tall aman cv Bakol (maturity 165 d) in the control (traditional practices) fields. Irrigation water varied across years depending on the amount of rain. The water use efficiency (WUE) was expressed as the ratio of grain yield to the amount of irrigation water applied. The yield and WUE of the control and study fields were statistically analyzed in a randomized block design, using number of observations as replications.

Water management

Vol. 22, No. 3 35

Effect of improved variety and water management practices on wet season rice crop in north Bihar, India.

Total Number of Grain yield (t ha -1 ) Total irrigation on WUE a

rainfall observations in different blocks water depth (cm) Saving in

water consumption Year in season in each block

(t ha -1 cm -1 )

(cm) Study Control CD (P=0.05) Study Control Study Control CD (P=0.05) (cm ha -1 )

1989 142.0 18 3.7 1.9 0.14 1990 91.4

24.4 46.7 9

1.4 2.8

0.4 0.06 22.3 1.9 0.51

1991 19.3 29.9

89.1 9 1.4 0.6 0.07

3.7 10.6

3.2 0.33 41.3 91.0 0.9 1992 58.4 6 2.0 1.8

0.3 0.10 49.7

1993 0.21 31.8 44.8

138.2 15 0.6 0.4 0.08

3.2 13.0

2.2 1994

0.31 18.0 18.0 1.2 0.04 96.6

1.7 9 3.1

0.0 2.4 0.33 21.0 32.0 1.0 0.6 0.05 11.0

a WUE = water use efficiency.

The results indicated that grain yield in the study fields averaged 34% more than in the control fields. The mean depth of irrigation water ranged from 18.0 to 41.3 cm in the study fields and 18.0 to 91.0 cm in the control fields.

The WUE also differed significantly, with higher values in the study fields than in the control fields. On average, yearly water consumption was 18.1 cm more in the control fields than in the study fields.

Improved rice varieties with improved water management practices can substantially increase yield as well as WUE on farms with irrigation.

On-farm water management studies in summer rice

S. Raman and N. D. Desai, Soil and Water Management Research Project, Gujarat Agricultural University, Navsari Campus, Navsari 396450, Gujarat, India

To demonstrate the significance of improved water management practices in rice cultivation, we conducted one large-scale experiment during the 1990- 93 summer (Feb-May) seasons in farmers’ fields using one of the minor canals off the main canal of the Ukai- Kakrapar command area in Gujarat. The clay soil was representative of those in the area for salinity and sodicity. The infiltration rate of the soil was 2.5 mm d -1 .

In the study plot (SP), 5 ± 2 cm of irrigation water was applied 1 d after standing water disappeared; in the control plot (CP), farmers’ practices were followed. Water depth in SP was observed using graduated, colored wooden pegs and the water application was measured using Parshall flumes installed in the canal. Water depth, measured periodically in CP, averaged 10±2 cm more across the crop growth period. No rain was received during any of the cropping seasons.

Based on the mean results (see table), 29% of the irrigation water normally used by farmers was saved, with about 55% higher yield per unit of water applied by adopting the improved water management practices. The yield increase (estimated by a

standard crop-cutting experimental technique) in SP was about 10.3% more than in CP. The increase could be attributed to the alternate wetting and drying in the treated plot, which might have resulted in better nutrient availability and less accumulation of toxic gases.

was brought under cultivation, especially at the end of the minor canal. Based on this research, irrigation authorities were convinced that the rice crop does not require continuous flooding at the usual higher water depths. Farmers did not experience yield reduction by using less water. Irrigating the extra 15% area used the same quantity of water normally allotted to the minor canal.

During the past 3 yr, 15% more area

Response of rice to water management practices. Gujarat, India. 1990-91 and 1993.

1990 1991 1993 Mean

SP a CP a SP CP SP CP SP CP

Total rice area (ha) 34.2 10.2 28.5 9.6 25.6 11.1 29.4 10.4 Total irrigation water 984 1580 1231 1762 1376 1717 1197 1686

Yield of rice (t ha -1 ) 5.988 6.037 6.715 6.130 7.179 5.855 6.627 6.007 WUE c of applied water 6.1 3.8 5.4 3.5 5.2 3.4 5.5 3.5 Water saved over 37.7 30.1 19.8 29.0

WUE c improved 57.7 56.6 52.8 55.3

Item

(mm ha -1 ) b

control (%)

over control (%)

a SP = study plot: CP = control plot. b Irrigation applied excluded the water requirement for raising seedling, puddling the field, and preparing the land. c WUE = water use efficiency.

36 IRRN 1997

Research methodology Use of the chlorophyll meter in N management of subtropical wheat following rice

Bijay Singh and Yadvinder Singh, Punjab Agricultural University, Ludhiana, Punjab, India; and K. F. Bronson, IRRI

In South Asia, researchers have reported that the highest wheat yields can be obtained by splitting the recommended N dose of 120 kg N ha -1 . For two splits, basal N at land preparation and an N topdressing at crown root initiation (CRI) or 20-25 d after sowing (DAS) are applied. Addi- tionally, N is sometimes added in a third dose at maximum tillering (MT) or jointing. The CRI and MT stages are times of irrigation, so the N fertilizer is applied just prior to irrigation to improve efficiency of N.

linked to irrigation at CRI and MT, options for topdressing at other times are limited. This practice is quite different from flooded rice culture where N topdressings can be applied at virtually any time. Using a chlorophyll meter in wheat culture, therefore, might have a role not in the timing of N topdressings but in determining whether a topdressing is needed or not, and, if so, possibly to predict how much. This prediction would be most important in the third split at MT because, depending on soil N supply, date of planting, and seasonal temperatures, N supply going into the reproductive stage of subtropical wheat may often suffice. The topdressing at MT can be evaluated as treatments with and without the application. Chlorophyll meter readings can be made on the day of MT topdressing and the “grain yield response” can be plotted against SPAD (soil-plant analysis development) readings. The critical SPAD reading for MT would be that corresponding to the

Since N fertilizer topdressings are

least significant grain yield response determined by LSD at P=0.05.

Evaluating the response of topdressing of wheat at MT with the chlorophyll meter is probably best done in farmers' fields where a large variation in available N in the soil at MT exists. Doing this study on station probably requires a range of basal N and CRI N to ensure “deficiencies” in the lower basal rate treatments at MT. Addition- ally, by varying the amount of N top- dressed at MT, we can see whether the chlorophyll meter prior to application can “predict” the N rate when it "predicts" a deficiency. Taking soil samples at the time of MT for exchangeable NH 4 and NO 3 would give additional information related to the need for N at that time. Inorganic N at harvest would be important to know as well since it might be present if MT N is applied when it is “not needed.” The SPAD reading at MT in wheat, therefore, may have a role in minimizing residual NO 3 at harvest which would be lost to denitrification or leaching when the field is flooded for rice.

A preliminary field trial evaluating the use of the SPAD meter for determining the need for MT N was conducted at Ludhiana, Punjab, India, in the 1996-97 rabi (wet) season. Wheat cultivar PBW 343 was planted on 28 Nov 1996 in 20-cm rows. Phosphorus was applied at the rate of 26.4 kg P ha -1 . Nitrogen was applied in four replicates (see table).

30 Jan 1997. Ten plants per plot were read, consisting of three readings per leaf.

Grain yield increased linearly from 3.3 to 4.6 t ha -1 with basal-plus-CRI-N rates of 60-120 kg N ha -1 . Response of grain yield to MT N ranged from -0.12 to 0.95 t ha -1 on plots that received 120 and 60 kg N ha -l of basal plus CRI N, respectively.

SPAD readings were taken at MT on

Grain yield from plots that did not receive MT N correlated positively with SPAD readings at MT (R 2 = 0.65, data not shown). When grain yield response to MT N was regressed against SPAD readings, the relationship was negative (see figure; R 2 = 0.60). The LSD for grain yield at P=0.05 for the difference between the 0 and 30 kg N ha -1 MT N treatments was 0.20. This minimum significant grain yield response corresponds to a SPAD reading of 44.0 (see figure). So if the SPAD reading at MT is less than 44, a topdressing of 30 kg N ha -1 should be applied because a response is expected. If the SPAD reading is greater than 44, then no response to N is expected. This procedure needs to be repeated for additional seasons and sites to see how robust the critical SPAD reading at MT of 44 is.

Nitrogen treatments used in the study.

Treat- Basal N CRI N Basal N MT N Total N ment (kg ha -1 ) (kg ha -1 ) + CRI N (kg ha -1 ) applied

(kg ha -1 ) (kg ha -1 )

1 0 0 0 0 0 2 30 30 60 0 60 3 30 30 60 30 90 4 40 40 80 0 80 5 40 40 80 30 110 6 50 50 100 0 100 7 50 50 100 30 130 8 60 60 120 0 120 9 60 60 120 30 150

Relationship between wheat grain yield response to N at maximum tillering (MT N) and SPAD readings.

Vol. 22, No. 3 37

Announcement 1998 Calendar of International Training Courses

Course/venue Trainees Duration (no.) (wk) dates

Inclusive

Experimental Design and Data Analysis (IRRI)

2-Week Rice Production Training Course (IRRI)

New Paradigms and Tools for Socioeconomic Analysis of Rice Production Systems in Asia (formerly Social Sciences Research Methods for Technology Design and Evaluation)

lntroduction to SAS for Windows (IRRI)

Strategic Research in Integrated Nutrient Management (IRRI)

Hybrid Rice Breeding (lRRI)

IRRl Stat for Windows

GIS Techniques for Agro-Ecosystems Characterization (IRRI)

Advanced Experimental Design and Data Analysis (IRRI)

15

25

12

15

25

25

15

14

15

2

2

8

1

5

8

1

5

2

12-23 Jan

19-30 Jan

9 Feb-4 Apr

16-20 Feb

16 Feb -20 Mar

2 Mar-25 Apr

23-27 Mar

30 Mar-1 May

6-17 Apr

Advanced Experimental Design (IRRI) 15 1 4-8 May 1 Gender Analysis in Agriculture, Forestry, & Natural Resources (IIRR, Silang, Cavite, Philippines)

Analysis of Unbalanced Data (IRRI)

Analysis of Categorical Data (IRRI)

Soil and Water Biochemistry and Ecotoxicology (IRRI)

lnstructional Video Production (IRRI)

Rice Seed Health for Crop Management Training Course (IRRI) 2 Integrated Pest Management in Rice (NCPC, UPLB, College, Laguna, Philippines) 3 Genetic Evaluation and Utilization for Rainfed Rice Ecosystems (URRC, Ubon, Thailand)

10

15

15

10

12

10

20

15

3

1

1

3

4

12

8

5

11-29 May

11-15 May

18-22 May

25 May- 12 Jun

1-26 Jun

1 Jul-20 Sep

6 Jul -28 Aug

15 Sep-15 Oct 4 Adaptive Research with a Farming Systems Perspective (FSSRI, UPLB, College, Laguna, Philippines) 20 8 21 Sep-30 Oct 5 Rice Production Research (PTRRC, Pathum Thani, Thailand) 25 8 5 Oct-27 NOV

6 Engineering for Rice Agriculture (IIT, Kharagpur, India) 25 6 2 Nov-11 Dec*

* Tentative schedule

Collaborating institutions: 1 International Institute of Rural Reconstruction (IIRR) and IRRI. 2 National Crop Protection Center (NCPC), University of the Philippines Los Baños (UPLB), Philippine Rice

Systems and Soil Resources Institute (FSSRI), PhilRice. UPLB, and IRRI. 5 Pathum Thani Rice Research Center (PTRRC) and IRRI. 6 Indian lnstitute of Technology (IIT) and IRRI. Research lnstitute (PhilRice), Southeast Asian Regional Center for Graduate Study and Research in Agriculture (SEARCA), and IRRI. 3 Ubon Rice Research Center (URRC) and IRRI. 4 Farming

For more information, contact

Dr. Robert T. Raab, Head Training Center, lnternational Rice Research lnstitute P.O. Box 933, 1099 Manila, Philippines

Phone: (63-2) 845-0563, 812-7686, 844-3351 to 53 Fax: (63-2) 891-1292, 845-0606

Email: [email protected]

Erratum Replace “true negatives” with “true positives” (box for Criterion 1) and "57.4%) true negatives” with "21.5%, true positives” (box for Criterion 2) in Figure 2b in “Method for detecting rice sheath blight pathogen in soil samples using mungbean,” IRRN 22(2):48-49.

38 IRRN 1997

mailto:[email protected]

Instructions for contributors NOTES IRRN categories. Specify the

category in which the note General criteria. Scientific being submitted should appear. notes submitted to the IRRN for Write the category in the upper possible publication should right-hand corner of the first • be original work, page of the note. • have international or pan- national relevance, GERMPLASM IMPROVEMENT • be conducted during the genetic resources immediate past three years or genetics be work in progress, breeding methods • have rice environment yield potential relevance, grain quality • advance rice knowledge, pest resistance • use appropriate research diseases design and data collection insects methodology, other pests • report pertinent, adequate stress tolerance data, drought • apply appropriate statistical excess water analysis, and adverse temperature • reach supportable conclu- adverse soils sions. other stresses

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

Multiple submissions. Nor- insects mally, only one report for a weeds single experiment will be other pests accepted. Two or more items water management about the same work submitted farming systems at the same time will be farm machinery returned for merging. Submit- postharvest technology ting at different times multiple economic analysis notes from the same experiment is highly inappropriate. ENVIRONMENT Detection will result in the SOCIOECONOMIC IMPACT rejection of all submissions on EDUCATION AND COMMUNI- that research. CATION

RESEARCH METHODOLOGY

integrated germplasm improve-

diseases

Manuscript preparation. Arrange the note as a brief statement of research objectives, a short description of project design, and a succint discussion of results. Relate results to the objectives. Do not include abstracts. Do not cite references or include a bibliography. Restrain acknowl- edgments.

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

Apply these rules, as appropriate, in the note:

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

• Use generic names, not trade names, for all chemicals. • Use the International System of Units for measurements. For example, express yield data in metric tons per hectare (t ha -1 ) for field studies. Do not use local units of measure. • Express all economic data in terms of the US$. Do not use local monetary units. Economic information should be presented at the exchange rate US$:local currency at the time data were collected. • When using acronyms or abbreviations, write the name in full on first mention, followed by the acronym or abbreviation in parentheses. Use the abbreviation thereafter. • Define any nonstandard abbreviations or symbols used in tables or figures in a foot- note, caption, or legend.

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

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

Comments. If you have comments or suggestions about the IRRN, please write to the editor.

Mailing address. Send notes and correspondence to the IRRN Editor, IRRI, P.O. Box 933, Manila 1099, Philippines. Fax: (63-2) 845-0606 E-mail: [email protected] Home page: http://www.cgiar.org/irri Riceweb: http://www.riceweb.org Riceworld: http://www.riceworld.org

mailto:[email protected]

http://www.cgiar.org/irri

http://www.riceweb.org

http://www.riceworld.org

international rice research notes vol.22 no.3

Documents