International Rice Research Notes Vol.20 No.4

8/4/2019 International Rice Research Notes Vol.20 No.4

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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 ricescientists to communicate with one another to obtain

details on the research reported.

The IRRN is published quarterly in March, June,

September, and December by the International Rice

Research Institute; annual subject and variety indexes are

also produced.

The IRRN is divided into three sections: notes, news

about research collaboration, and announcements.

The IRRN is a mechanism to help scientists keep each

ContentsDecember 1995

Genetics

Loci for hybrid sterility in Basmati crosses 4Diallel analysis of AI toxicitytolerance in rice 5

Breeding methods

Maintainers and restorers for cytoplasmic male sterile line

Biological characteristics of indica-japonica hybrids 6

Grain quality

Glutelin banding pattern in rice assessed 7

lR66707A 5

IRRN production team. . . . . . . . . . . . . . .

Editor: Carolyn Dedolph

Assistant editor: Teresita Rola

Layout and design: Erlie Putungan

Production supervisor: Millet Magsino

Editorial assistant: Luisa Gelisan

Typesetting: Erlie Putungan

Cecilia Gregorio

Artwork: Jess Recuenco

2 IRRN 20:4 (December 1995)

Stress tolerancedrought

Leaf rolling and desiccation tolerance in relation to rooting depth

and leaf area in rice 7

Stress toleranceadverse soils

Tolerance for AI toxicity in lowland rice 8

Integrated germplasm improvementirrigated

Karnataka Rice Hybrid-1, a short-duration hybrid for Karnataka,

Xiangyou 63, a quasi-aromatic hybrid rice with good quality and

Zhushan A: a new Honglian-type cytoplasmic male sterile line

India 9

high yield 9

with good grain quality 10

Integrated germplasm improvementupland

Turant Dhan: a very early rice variety released in Bihar, India 11

Integrated germplasm improvementflood-prone

Purnendu, a new deepwater (50-100 cm) rice variety in eastern

Jitendra, a new deepwater rice variety for Uttar Pradesh and West

India 12

Bengal, India 13

Seed technology

A simple method for producing F1 hybrid seed for observational

yield trials 13

Physiology and plant nutrition

Proline content in rice seedlings grown under saline

Photosynthetic rate and respiration of some F1 hybrid rices 15

Fertilizer management

Integrated effect of deeply placed urea and Gliricidia green

conditions 14

manure on grain yield of transplanted rice 16

Germplasm improvement

Crop and resource management

Germplasm improvement



3/34

Effect of rice hull, biofertilizer, and chemical fertilizers on

growth and nitrogen economy of wetland rice 16

Fertilizer managementorganic sources

Influence of intercropping green manure in wet seeded

rice 17

Crop management

Effect of hill density, seedling number/hill, and potassium

on late-transplanted sali (rainfed lowland winter) rice yield

in Assam, India 18

Integrated pest managementinsects

Monitoring variation in brown planthopper biotype in

Guangdong, China 19

Integrated pest managementtheir pests

Loss of harvested rice due to rodents in central India 20

Farming systems

Farmer performance in a rice-based farming system:

differences between new and old systems 21

Farm machineryHand tools used for rice harvesting in South Sulawesi,

Indonesia 21

Postharvest technology

Multipurpose yard-drying implement for rice 22

Repetitive sequence-based polymerase chain reaction of

Xanthomonas oryzae pv. oryzae and Pseudomonas

Pathotypic analysis ofPyricularia grisea using two sets of

species 23

near-isogenic lines 24

INGER celebrates 20 years of successful rice research 26

IRRI celebrates 35 years of rice research 27

IRRI welcomes two majorgroups of partners 27

Rice dateline 27

IRRI group trainingcoursesfor 1996 28

New IRRI publications 28

New publications 29

Rice literature update reprint service 29

Call for news 29

IRRI address 29

Inside back cover

IRRN 20:4 (December 1995)

Instruction for contributors

International Rice Genetics Symposium 27

Research methodology

News about research collaboration

Announcements

ErratumInstruction for contributors


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Germplasm improvementcompletely fertile, the variety may be used

as a restorer. However, interference of

Loci for hybrid sterility in Basmati hybrid sterility genes with a CMS-restora-

crossestion factor system very much confounds the

criteria used in the screening.

Jianmin Wan, Nanjing Agricultural University, Hybrid sterility in indica-japonica

Nanjing, 210095, China; H. Ikehashi, Faculty crosses is due to an allelic interaction at a

of Agriculture, Kyoto University, Kyoto 606-1, gamete abortion locus, S-5, on chromosome

Japan 6. Recently, in other groups of rice hybrids,

similar allelic interactions were found at

Massive screening has been conducted in loci S-7on chromosome 4, S-8 on chromo-

hybrid rice breeding to determine if a set of some 6, S-9 on chromosome 7, and S-15 on

varieties can be used as maintainers or chromosome 12. All of them cause sterility

restorers. If the pollen of an F1 hybrid independent of the others.

between a cytoplasmic male sterile (CMS) We found hybrid sterility loci in crosses

tester and any given variety is sterile, the with Basmati 370, the derivatives of which

variety may be used as maintainer. If the are frequently used in hybrid rice breeding.

pollen is sound and the panicles of the F1 are Basmati 370 showed hybrid sterility in its

Table 1. Varieties used and their marker alleles at respective loci.a

Marker allele and chromosome

Parent Chromosome Chromosome Chromosome Chromosome Chromosome7 4 12 16

Basmati 370AkihikariIR36lR2061-628lR2061-418Gilchao 2Ketan Nangka

Est-2 Amp-3 Cat-1 Est-9

(S-5) (S-8) (S-7)

1 1 2 10 1 2 12 1 1 22 1 1 22 1 1 22 1 1 21 2 2 1

Est-1

(S-9)

0011110

(S-15)

Sdh-1

2211112

(S-16)Est-5b

2111111

a The isozyme allele systems are from Morishima and Glaszmann (1991). bThree hybrid sterility loci are shown under

the marker loci.

crosses to several tester varieties. Spikelet

fertility levels in some of the crosses were

67.2% in Basmati 370/IR36,61.3% in

Basmati 370/IR2061-628,62.8% in Basmati

370/IR2061-418, and 43.2% in Basmati 370

Akihikari. The F1 hybrid of Basmati 370/

Ketan Nangka (wide compatibility variety)

showed normal fertility of 90.1%.

Marker alleles at each of the hybrid

sterility loci wereidentified (Table 1).

Basmati 370 is closer to japonicas in terms o

its isozymes, therefore it is genetically

diverse from indicas and should result in

pronounced hybrid vigor in its crosses with

indicas.

The marker genotypes that differentiated

the level of spikelet fertility in segregating

populations were determined (Table 2).

When Basmati 370 was crossed with

major indica varieties, such as IR36 and

IR2061-628, hybrid sterility was revealed

due to an allelic interaction at S-8. In the

cross Basmati 370/IR2061-418, hybrid

sterility was due to an allelic interaction at

S-7. In Basmati 370/Akihikari (a japonica

tester), hybrid sterility was affected by at

least the alleles at S-5.

We believe that the difficulties in using

Basmati 370 in hybrid rice breeding pro-

grams are caused by its allelic interactions at

several hybrid sterility loci. Systematic use

of neutral alleles at each locus is recom-mended to solve the problem.

Table 2. Distribution of spikelet fertility classified by marker genotype of hybrids between Basmati 370 and IRRI lines or a japonica test line. a

Number of plants in spikelet fertilityGenotype

10 20 30 40 50 60 70 80 90 100Total mean T-test

Basmati 370/1R36//1R36

Cat-12/Cat-11 2 3 3 5 9 10 3 3 2 0 40**b 52.3**

Cat-11/Cat-11 2 1 2 1 1 2 1 17 18 16 61 75.8SF was not differentiated at Est-2, Est-9, Est-1, Sdh-Tand Est-5

Basmati 370/lR2061-628//Basmati 370

Cat-12/Cat-12 1 1 1 1 0 2 8 10 8 6 38** 76.3**

Cat-11

/ Cat-12

3 2 2 4 7 9 8 8 8 -4 55 51.7SF was not differentiated at Est-2, Est-9, Est-1, Sdh-1, and Est-5

Basmati 370/IR2061-418//Basmati 370

Est-92/Est-91 2 2 3 3 6 3 14 8 5 4 50** 56.3**

Est-91/Est-91 1 1 1 2 1 1 4 10 10 6 37 74.3SF was not differentiated at Est-2, Cat-1, Est-1, Sdh-1, and Est-5

Basmati 370/Ketan Nangka//AkihikanAmp-32/Amp-31 0 1 0 0 3 2 14 11 7 5 43 76.5**Arnp31/Amp-31 2 1 2 3 4 2 4 7 5 3 33 52.3

aNumbers underlined are assumed to be recombinants. b** = significant at the 1% level.


GeneticsGenetics


5/34

Diallel analysis of AI toxicity

tolerance in rice

S. Khatiwada, D. Senadhira, and R. S.

Zeigler, IRRI; A. L. Carpena and P. G.

Fernandez, University of the Philippines Los

Baos, Laguna, Philippines

We studied the genetics of Al toxicity

tolerance using a full diallel set of crossesamong seven parents with differing degrees

of response to Al toxicity. The seven vari-

eties were Moroberekan, IRAT104, and

Azucena (tolerant); IR29 and IR43 (moder-

ately tolerant); and IR45 and IR1552 (sus-

ceptible).

Relative root length of 14-d-old seed-

lings, determined by growing seedlings in a

normal nutrient solution and nutrient

solution with 30 ppm Al, was used to

characterize the tolerance of test materials.

The experiment was conducted in a

glasshouse at the IRRI Phytotron with

29/21 C day/night temperature and 70%

relative humidity. The experimental units

consisted of 49 entries (7 7 diallel) in

randomized complete block design with

four replications. Eight seedlings were

sampled for each entry in a replication.

Analysis of variance among parents,

hybrids, and reciprocals showed highly

significant differences among parents and

hybrids. Differences between parents and

hybrids were not significant. Analysis of

variance of the diallels revealed homogene-ity of error variance, directional dominance,

symmetrical distribution of genes among

parents, and that no parent had more

dominant genes than did the others.

Covariance-variance graphic analysis

showed the adequacy of a simple additive-

Estimates of genetic parameters for relative root length (AI toxicity tolerance) in 7 7 diallel crosIRRI, 1995.

Genetic parameter Estimate SE

(D) Additive effects(H) Dominance effects

H1 (due to dominant gene)

H2 (due to positive and negative genes)

h2 (due to heterozygous loci)(F) Gene distributlon

(E) Environmental effects

0.0167 0.0005* a

0.0041 0.0015*

0.0034 0.0013*

0.0002 0.00090.0028 0.0015

0.0008 0.0002*

Proportional values

(H1/D) Mean degree of dominance 0.4954(H2/4H1) Proportion of genes with + or - effects on parents 0.2082(KD/KR) b Proportion of dominant and recessive genes in the parents 1.4001r

c Correlation between (Wr+Vr) and Yr 0.6618r

2 Prediction for measurement of completely dominant and

recessive parents 0.4380

and inhibit dominance 0.0654

(h2/H2) Number of gene groups that control tolerance

(hns) Heritability (narrow sense) 0.8177

(hbs) Heritability (broad sense) 0.9106

a * = significant at P


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9.0 a 24.6 220.0 69.1 22.3 12.0 18.6

the frequency of maintainers in the CMS-

O. perennis system was very high and the

frequency of restorers very low.

IR21820-38-2 and Mahsuri produced

hybrids that yielded about 40% more than

check IR36 (Table 2.)

Biological characteristics of indica-

japonica hybrids

Lu Chuan'gen, Gu Fulin, and Zou Jiangshi,

Jiangsu Academy of Agricultural Sciences

(JAAS), Nanjing 210014, China

Five indica-japonica hybrids and their

parents were tested for their biological

characteristics. The experiment was

conducted in a 40-m2plot with three

replications per variety at the JAAS

experimental farm in 1990 and 1991. The

hybrids were obtained by crossing indica

lines and japonica wide compatibility lines

with the S-5n gene.

The hybrids had grain yields of 7.6-10.6

t/ha and significant heterosis of 13.8-83.1%

over the average of their parents. More

spikelets per panicle in the hybrids caused

the sink capacity to increase by 27.0-70.4%

over that of the parents, thus contributing to

high grain yields. The panicles per area,

however, exhibited no heterosis (Table 1).

The biomass of the hybrids averaged

about 18 t/ha. It exceeded that of the parents

by 11.5-41.1% and was the biological basis

for the hybrids' high grain yield. High leaf

Table 1. Maintainers and restorers for lR66707

A. CRRI, Cuttack, India. 1992 and 1993 wetseasons.

Male parent M/Ra

1992

ADT34AnnadaB4143 D-PM-51-4BKS64CR580-17-3

CR564-8CR644CRM 35DayaIET10158

IET10983lR1846-300-1lR25560-109-3-1-3-2

Krishna

Mizoram 24Mizoram 35Mizoram 41Mizoram 51Mizoram 61

Mizoram 62

PanidhanPusa 33Rasi

SarasaSuphalaSavitriTulasiV20

GayatriMizoram 39

lR1248-242-32

PN56-665

MMMMM

MMMMM

MMMMM

MMMMM

MMMMWM

MMMMM

PRb

PR

1993

ARC1355886441-5. MR. 10-1BR1870-88-11Col. 155C1954-24-2

MMMMM

C2757-22-1-1-1 MlR49689-84-2-1-2 MlR35366-28-3-1-2-2 MlR48725-B-B-120-1 MlR27315-145-1-3-2 M

KatarniPusa 33-303Vijaya

MMM

lR49721-127-2-2-1 PR

Raktachandan

Tox 3108-43-3-6lR21820-38-2Mahsuri

PRPRR*1c

R*2d

aM = maintainer (spikelet fertility


7/34

Table 2. Comparison of some physiological traits of Yayou and Shanyou 63. Nanjing, China, 1989.

Trait Yayou 2 Shanyou 63 Compared

Maximum leaf area indexMaximum photosynthetic rate

(mol CO2 /m per s)Specific leaf weight in heading

(mg/cm2)Chlorophyll content in heading (%)Relative growth rate (g/kg per d)

Net assimilation rate (g/m2 per d)Period leaf activity (d)

8.2 7.1

24.0 20.9

4.6 3.84.9 4.0

40.9

9.673

(check) with check a

37.8

6.454

+15.5%

+14.8%*

+21.1%*

+22.5%*+8.2%

+50.0%+35.2%*

a *= significant difference at the 5% level.

area index (LAI) and leaf area duration of 0.5, which was 6.4% higher than that of

(LAD) caused a high crop growth rate in the the check. Its LAI increased at a rate of

hybrids, leading to the higher average 10.2% per day in the earlier growth stages,

biomass than that of the parents. There was which was faster than that of the check, and

no heterosis in harvest index. decreased at 2.0% per day in the later

The grain yield potential increased to stages, which was slower than that of the

11.1-12.5 t/ha, which was much higher than check. Its maximum LAI was 1.1 and its

that for the indica or japonica lines. Seed LAD 25.5%both higher than those of the

set, however, was low and unstable com- check. Yayou 2 had a leaf photosynthetic pared with that of the parents, although the rate 14.8% higher than the check and a daily

S-5n gene was used. High and stable seed set bio-mass accumulation of 17.1% more

should therefore be the main objective for (Table 2).

cultivating and breeding indica-japonica The leaves of Yayou 2 were droopy

hybrids. during the early growth stage but later

An example of an indica-japonica hybrid became erect, resulting in a lower light

rice is Yayou 2. It was developed by using a

chemical hybridizing agent and by crossing

indica line 3037 and japonica wide compat-

ibility variety 02428. We compared some of

its traits with check Shanyou 63, a widely

cultivated indica hybrid.

Yayou 2 showed a grain yield potentialof 12 t/ha, 21 t/ha of biomass (1 3% higher

than that of the check), and a harvest index

Glutelin banding pattern in rice

assessed

B. Kalita and G. N. Hazarika, Agricultural

Biotechnology Program, Plant Breeding and

Genetics Department, Assam Agricultural

University, Jorhat 785013, Assam, India

The high stability of the seed protein profile

and its additive nature make seed protein

electrophoresis a powerful tool in elucidat-

ing the origin and evolution of cultivated

plants. The electrophoregram obtained by

polyacrylamide gel electrophoresis (PAGE)

of storage proteins is used mostly for

extinction coefficient and a higher light

transmission in the later stages. Compared

with the check, Yayou 2 had a higher

translocation coefficient of stored sub-

stances in the sheath, leaf, and stem; a

higher relative growth rate and net assimila-

tion rate in the earlier stages; and a longeractive period for the three top leaves.

assessing variation in chemical composi-

tion among cultivars and populations of

land races. Scientists have also established

an association between electrophoretic

components and quality characters in

cereals.

Glutelin is the major seed storage

protein of rice, contributing 80% of the total

endosperm protein. We examined the

glutelin banding pattern in 72 japonica and

indica rices using the sodium dodecyl

sulfate PAGE technique. Three were

japonica varieties (Jinbu 4, Vailoninano,

and Stagaree E) and 69 were indica varie-

ties, classified as nonscented (23), scented

(13), glutinous (9), semiglutinous (9), and

deepwater (15).

The different indica varieties showed a

similar banding pattern for the major bands

The only exception was the scented variety

Kosturi. We observed it to have one

mobility variant 6s (Rf= 0.67) for band 6,

which contributed to a higher molecular

weight than the corresponding band in othe

varieties (Rf= 0.72). Differences for some

minor bands were noticed among sub-

groups of indica varieties.

was not found within japonica varieties.

However, indica and japonica varieties

showed variation for the major band 6. The

japonica varieties also had a mobility

variant 6s (Rf= 0.67) similar to that of

Kosturi.

These findings show that glutelin

components in rice are conserved, unlike

prolamines of wheat and barley. The

similarity between indica variety Kosturi

and japonica varieties for the slow migrat-

Similarly, variation for glutelin subunits

ing band 6s indicates the probability of

these being distantly related. A detailed

study is needed to conclude whether the

presence or absence of minor bands in

different rice groups has something to do

with varietal characteristics.

Leaf rolling and desiccation

tolerance in relation to rooting

depth and leaf area in rice

A. R. Gomosta and M. Z. Haque, Plant

Physiology Division, Bangladesh Rice

Research Institute, Gazipur 1701, Bangla-

desh

Greater rooting depth is associated with

drought tolerance in a rice variety. How-

ever, more water is lost from plants with a

higher leaf area. A balance between

rooting depth and leaf area is perhaps

important. This study was done to under-

stand the relative importance of these two

traits in leaf rolling and desiccation

tolerance.

Different rooting depths were created

by placing perforated polyethylene sheets

at 5, 10, and 15 cm in the soil. One treat-

ment with no polyethylene sheet was used

as the control. Fertilizer at 20-40-60 kg

NPK/ha was applied before IR5 was dry


Grain quality

Stress tolerance

drought

Grain quality


8/34

Water saturation deficit, leaf rolling, and desiccation tolerance of rice as affected by rooting depthThe soil moisture percentage around the

and leaf area.a

root zone decreased as rooting depth de-

Rooting Leaf WSDb Leaf Desiccationd Root zone creased. Soil moisture was also reduceddepth area (%) rolling tolerance

(cm) (%) (1-5) c (1-9) (%)

moisture with increased leaf area, but only at 5- and

5 100 86.0 a 5.0 a 9.0 a 4.0 c leaf area did not affect the root zone mois-5 50 71.0 b 5.0 a 9.0 a

10 100 50.0 c 5.0 a 8.0 a6.0 c ture.6.0 bc

10 50 31.0 d 4.0 a 7.0 a 8.0 ab Like rooting depth, the leaf area also sig-

10-cm rooting depths. At 15 cm or deeper,

15 100 25.0 de 3.0 b 7.0 a 8.0 a nificantly determines the plants internal

15 50 7.0 f 2.0 eControl

1.0 c100 15.0 ef 3.0 b

9.0 a4.0 b

water balance as well as its desiccation tol-

Control 50 6.0 f 2.0 c 1.0 c 9.0 a10.0 a

erance. However, the degrees of leaf rolling

CV (%) 23 11 20 16 and leaf desiccation were significantly re-

aFigures with the same letter(s) do not differ significantly at the 1% level.

b WSD (water saturation deficit) (%) =

cRated on a 1-5 scale where 1 = no leaf rolling and 5 = leaves severely rolled. dRated on a 1-9 scale where 1 = no

desiccation of leaves and 9 = leaves severely desiccated.

Turgid weight field weight

Turgid weight oven-dry weight 100.

seeded. Seedlings were sprinkled with

turgid in water. This was measuredclipped to half at 21 d after seeding.

deficiency relative to when a leaf was 100%water for the first 3 wk. The leaf area was percentage (WSD%), defined as water

The internal water stress of the leaves gravimetrically. The WSD% increased with

was expressed as the water saturation deficit decrease in rooting depth (see table).

duced with decreased leaf area at 15 cm

rooting depth or more. At 5- and 10-cm

rooting depths, leaf rolling as well as desic-

cation tolerance were statistically similar at~~

100% and 50% leaf area.

Thus, less leaf area is more important at

greater rooting depths than at shallower

rooting depths when desiccation tolerance

of a variety is considered.

Relative root length of some traditional rice va-

Tolerance for Al toxicity in lowland India, Indonesia, Malaysia, Thailand,rieties grown in normal and AI toxic nutrientsolution.

rice

S. Khatiwada, D. Senadhira, and R. S.

Zeigler, IRRI; A. L. Carpena and P. G.

Fernandez, University of the Philippines Los

Baos, Laguna, Philippines

A major production constraint in acid

upland soils is Al toxicity. So far, screening

rices for Al tolerance has been limited to

upland cultivars. However, lowland rice is

grown on about 2 million ha with acid

sulfate soil conditions. These rices are

prone to Al toxicity during dry spells.

Several Al-tolerant upland rices have been

identified, but their use in acid lowlands as

cultivars or as donors for breeding purposes

is very limited because they are japonicas.

Previous investigations showed that

relative root length (RRL) of 2-wk-old

seedlings (determined as the ratio of root

length in a nutrient solution with 30 ppm Al

to the root length in a normal nutrient

solution) is a good criterion for selectingAl-tolerant genotypes. With the objective of

isolating AI-tolerant lowland indicas, we

used this technique to screen 62 cultivars

originating from acid sulfate soil areas of

Vietnam, and West Africa.

The experiment, which was laid out in a

randomized complete block design with

two replications, was conducted in an IRRI

Phytotron glasshouse with 29/21 C day/

night temperatures and 70% relative

humidity. IRAT104 was used as the tolerantcheck and IR1552 as the susceptible check.

Eight seedlings were sampled for each test

entry in a replication.

The differential tolerance for Al among

cultivars was found highly significant (see

table). RRL ranged from 0.45 in S-4 to 1.16

in Siyam Kuning. The RRL was 0.83 for

tolerant check IRAT104 and 0.57 for

susceptible check IR1552. In 17 varieties,

RRL was 1.0 or more, indicating that Al did

not affect the root growth of these cultivars.

Other researchers earlier reported increases

in root length and growth of seedlings of

tolerant cultivars when exposed to added

Al.

The difference in RRL means between

tolerant check IRAT104 and the two best

performing test varieties (Siyam Kuning

and Gudabang Putih) was highly signifi-

cant. This finding suggests that the toler-

ance of these two cultivars is very much

Variety

Siyam Kuning

Gudabang PutihSiyam

Lemo

Khao Daeng

Siyamhalus

Bjm-12

Ketan

Seribu Gantang

Bayar Raden RatiPadi KanjiBjm-13Batang PaneBjm-14Ca Dung DoBjm-10Padi JambiGablak Cablak

BaritoEngatekBjm-15

Siyam Kuning

Quisidugo

Lua ThuocGudabang Kuning

Bjm-17Kutik PutihKapuasBaiang 6Pontianak

Relative

lengthaOrigin root

Indonesia 1.16

Indonesia 1.14Indonesia 1.10Indonesia 1.09

Thailand 1.08

Indonesia 1.06

Indonesia 1.06

Indonesia 1.06

Malaysia 1.05Indonesia 1.05Indonesia 1.04Indonesia 1.04Indonesia 1.04Indonesia 1.04Vietnam 1.04Indonesia 1.04Indonesia 1.03Indonesia 0.96

Indonesia 0.94Malaysia 0.93Indonesia 0.93

Indonesia 0.93

West Africa 0.93Vietnam 0.92

Indonesia 0.92Indonesia 0.90

Indonesia 0.90Indonesia 0.89lndonesia 0.89Indonesia 0.85

continued on nextpage


Stress toleranceadverse soils


9/34

Table continued

Variety

Relative

lengthaOrigin root

Nang CoiBayar KuningBjm-11

Thung Hoa Binh

Alabio

Khao Seetha

Gaw Diaw BowKhao TaengLua Thuoc Co

Talang A

Mahakam

GalambongTai Nguyen

KetumbarThom RanTalang B

Duvi TrauCan Dung PhenGogo RancehDoc Phung

Nang GaoMansirit

Kapus

YacaS-1

VietnamIndonesia

IndonesiaVietnam

Indonesia

Thailand

IndonesiaThailandVietnam

Indonesia

Indonesia

Indonesia

VietnamIndonesia

VietnamIndonesiaVietnamVietnamIndonesiaVietnamVietnam

Indonesia

Indonesia

West AfricaWest Africa

0.850.850.85

0.85

0.81

0.81

0.800.800.79

0.78

0.78

0.770.77

0.740.740.73

0.700.70

0.700.680.67

0.67

0.66

0.660.66

Atanha West Africa 0.62

Nang Co Vietnam 0.62

Than Nang Do Vietnam 0.62Pokkali India 0.62SOC Nau Vietnam 0.59Silla West Africa 0.57

S-4 West Africa 0.45IRAT104 (tolerant check) 0.83

lR1552 (susceptible check) 0.57CV (%) 12.5LSD (0.05) 0.21LSD (0.01) 0.28

a Mean of two replications.

higher than that of IRAT104. Varieties

Siyam, Lemo, Khao Daeng, Siyamhalus,

Bjm- 12, Ketan, Seribu Gantang, Bayar

Raden Rati, and Padi Kanji also produced

significantly higher RRLs than did

IRAT104. The tolerance level of the other

cultivars was comparable with that of

IRAT104. Only three of the 62 varieties

expressed sensitivity.

The results indicated that tolerance for

Al toxicity exists in lowland varieties grown

on acid sulfate soils. The cultivars that are

more tolerant of Al than upland cultivar

IRAT104 may be good donors for breeding

Al-tolerant lowland rice varieties.

Karnataka Rice Hybrid-1, a short-

duration hybrid for Karnataka, India

B. Vidyachandra, R. M. Radhakrishna, S.

Lingaraju, A. H. Krishnamurthy, and V.

Bhaskar, University of Agricultural Science,

Regional Research Station (RRS), V. C. Farm,

Mandya 571405, Karnataka, India

Karnataka Rice Hybrid-1 (KRH-1) is a

short-duration rice hybrid selected at RRS

from rice hybrids shared by IRRI through

the Directorate of Rice Research,

Hyderabad. Its parents are cytoplasmic

male sterile line IR58025 A and restorer

line IR9761-19-1 R.

KRH-1 matures in 125 d and is 90-cm

tall. It produces an average of 460 panicles/

m2 and 168 grains/panicle. The grains are

long-slender and straw-colored, the kernels

are white, and the 1,000-grain weight is

23.3 g. It is for use in the irrigated areas of

Karnataka. The recommended fertilizer

dose for KRH-1 is 100-50-50 kg NPK/ha.

The seed rate is 20 kg/ha with single

seedlings per hill at 20- 10-cm spacing.

KRH-1 recorded a yield advantage of1.5 t/ha over check Mangala in trials

conducted during 1990-93 at Mandya (see

table). Similar results were obtained in

multilocation trials and in 100 on-farm

trials around Karnataka, in which KRH-1

yielded an average 6.8 t/ha with a yield

advantage of 1.5 t/ha over Mangala. KRH-

has moderate resistance to neck blast,

sheath rot, and stem borer.

The State Variety Release Committee

released KRH-1 during 1994 for cultivatio

in Karnataka State.

Mean yield (t/ha) of Karnataka Rice Hybrid-1 (KRH-1) in different trials in Karnataka, India. 1990

93.

Type of trial Year Trials KRH-1 Mangala Yield

(no.) (check) advantage

Research station 1.5

Multilocation 1991-93 18 5.3 3.7 1.6

1991-93On-farm 100 6.8 5.3 1.5

Mean 6.4 4.9 1.51.3

1990-93 10 7.2 5.7(Mandya)

Demonstration 1993 10 6.3 5.0

Xiangyou 63, a quasi-aromatic The hybrid, which produces only some

hybrid rice with good quality and aromatic grains on each plant, has somehigh yield advantages over aromatic inbred or hybrid

rices. In China, aromatic inbred and hybrid

Zhou Kunlu and Liao Fuming, Hunan Hybrid rices are usually mixed before cooking with

Rice Research Center (HHRRC), Changsha

aroma. Xiangyou 63 grain, however, is410125, Hunan, China

nonaromatic rice to lessen their intense

Xiangyou 63 was developed at HHRRC Another advantage is that its grains are not

using aromatic cytoplasmic male sterile line as easily attacked by insect pests and rats as

Xiangxiang 2 A and nonaromatic restorer are those of aromatic rices, and that it is also

line Minghui 63. It was released to farmers relatively easier to store than aromatic rice.

in Jan 1995. Xiangyou 63 is the first quasi- All of Xiangyou 63s quality characters,

aromatic hybrid rice in China, and except brown rice percentage, meet the firs

Xiangxiang 2A, developed from the cross and second class standards of fine quality

first aromatic CMS line in China. The Agriculture (Table 1). It has been endorsed

hybrid has so far been planted on more than as a fine quality rice in Hunan, Guangdong,

20,000 ha and seems popular with farmers Yunnan, Guizhou, Shaanxi, and Henan

and consumers. In addition to being provinces.aromatic, the hybrid has good grain quality, Xiangyou 63 yielded an average of

high-yielding ability, good disease resist- about 6.9 t/ha in various trials during 1987-

ance, and wide adaptability. 89. For example, in the 1988-89 Hunan

already mixed due to F2 segregation.

V20A//N20 B/MR365 by HHRRC, is the rice issued by the Chinese Ministry of


Integrated germplasm improvementirrigated


10/34

Table 1. Grain quality performance of Xiangyou 63.

74 >59 6.5-7.5 >3.0 60 17-22 >8

Ministry of

Agriculture 2nd class >79 >72 >54 5.6-6.5 2.5-3.0standard

aHRRI = Hunan Rice Research Institute, CNRRl = Chinese National Rice Research Institute, and SGAB = Shaoguan Agricultural Bureau. b Xiangyou 63 did not mature very well in

1990 because of late sowing, which gave lower head rice and higher chalky rice percentages than the other results.

Table 2. Agronomic characters of Xianyou 63. Hunan Rice Variety Regional Trial, China, 1988.

Hybrids Replica-

HybridPlant Spikelets/ Filled 1,000- Grain

Locations tested tions Maturity height panicle spikelets grain yielda

(no.) (no.) (no.) (d) (cm) (no.) (%) weight (t/ha)

(g)

Xiangyou 63 15 10 3 126 99 91.9 81.1 28.1 6.7 nsWeiyou 6 (check) 15 10 3 127 88 94.5 80.4 26.6 6.6

ans = yields not significant by Duncan's SSR test.

Table 1. Heading date, fertility, and general combining ability (GCA) effects for grain quality characters of Zhushan A, Zhenshan 97 A, and Guang 41 A

Zhangjiang, China. 1991-93.

Trait

Fertility (%) Relative value of GCA effects (%)c

CMS linea

Days toheadingb Pollen Stained Spikelet Chalkinessd Length e Width f Length-width Milling rate of

head rice (%)sterile pollen (cm) (cm) ratio polished

Zhushan A 78 12 0-0.1 9.7-63.3 0-0.2 10.3* g 3.9* 8.3** 12.6** 3.2**

Zhenshan 97 A (check) 69 12 0-0.1 3.0- 6.8 0-0.1 7.2**g 1.5 6.0** 7.15 1.4

Guang 41 A (check) 86 16 0-0.1 8.2-55.1 0-0.1 3.1* 2.4 2.3 5.5 1.8

SE for GCA value 1.3 1.6 2.0 4.5 1.2

aZhenshan 97 A is a leading wild abortive CMS line in China. Guang 41 A is a leading Honglian-type CMS line in Guangdong Province, China. bMean values across 16 seeding times

from 3 Feb to 13 Aug 1992. cThe six restorer lines, R59, R56, R892, Zaoteqing, Gujinyang, and 771, that can restore the fertility of both Honglian-type and wild abortive-type CMS

lines were used in an Incomplete diallel experiment. dMeasured using the Standard evaluation system for rice. eSum of the length of 10 brown rice grains. fSum of the width of 10

brown rice grams. g*, ** = significant at the 5 and 1% level, respectively.



11/34

observe the traits of Zhushan A, to test its

general combining ability (GCA) effects on

some grain quality characters, and to

determine the yield capacity of the new

hybrids from Zhushan A.

Zhushan A has good plant type and is

about 85 cm tall. It has dark green leaves,

erect flag leaves, and long-slender grain

(9.1 mm long 2.6 mm wide). Its heading

date was 78 d, which was 9 d longer than

that of Zhenshan 97 A and 8 d shorter than

that of Guang 41 A (Table 1). Pollen fertility

was 0-0.1%. Like the Honglian-type CMS

line Guang 41 A, Zhushan A had 9.7-63.3%

stained sterile pollen. The sterility of

Zhushan A is acceptable for commercial

hybrid rice production in southern China.

the relative values of GCA effects of the

parents were estimated by Bulmer's

method. Zhushan A had higher GCA effects

for grain length, length-width ratio, and

milling rate of polished head rice than did

Zhenshan 97 A and Guang 41 A, but lower

GCA effects for chalkiness and grain width.

Therefore, Zhushan A could be used to

produce hybrids with lower chalkiness,

grain length, grain width, length-width ratio

in grain, and milling rates of polished head

rice (Table 1).

Yield trials were laid out in a random-

ized complete block design with three

replications. Four of the hybrid crosses

from Zhushan A yielded 8.0-8.4 t/ha during

the early cropping season (5.6-10.7% morethan the national check Shanyou 63) and

6.9-7.1 t/ha during the late cropping season

(2.5-5.4% more than the provincial check

Shanyou 64) (Table 2). For the four hybrids,

grain length was 6.1-6.8 mm; length-width

ratio, 2.5-3.2; chalkiness, 0-1; amylose

content, 19.7-23.5%; and grain quality,

grade 1 or 2. In the 1993 early cropping

season, Zhuyou 61 (Zhushan A/R61)

yielded 7.7 t/ha, ranking first among 14

crosses in the united test of high-quality

hybrid rice of southern China. Zhuyouqing

(Zhushan A/Meiqing) ranked second in a

regional test during the early cropping

season in Guangdong Province.

Zhushan A has greater GCA for grain

quality characters than do other CMS lines.

The hybrid crosses derived from Zhushan A

have good grain quality and higher grain

yield, making the line valuable for use in

breeding programs.

In a 3 6 incomplete diallel experiment,

Table 2. Grain yield and grain quality of several Zhushan A hybrids. Zhanjiang, China. 1991-93 ear

and late cropping seasons. a

Hybrid

Zhushan A/Meiqing Zhushan A/R61 Zhushan A/R903 Zhushan A/R54

Early Late Early Late Early Late Early Late

Grain yield (t/h) 8.0 7.1 8.2 7.0 8.3 7.0 8.4 6.9

Checkb 5.6 5.4 8.1c 4.0 8.7* 3.7 10.7** 2.5

Grain quality

Grain length (mm) 6.1 6.7 6.5 6.8 6.6 6.8 6.4 6.6Length-width ratio 2.5 2.7 2.7 3.0 3.0 3.2 2.8 3.1

Chalkiness 0-1 0-1 0-1 0-1 0-1 0-1 0-1 0-1

Amylose content (%) 22.0 21.1 23.5 21.0 20.8 21.3 19.7 21.8Quality graded 2 1 2 1 1 2 2 1

a Early crop was seeded in February, late crop was seeded in July. b Shanyou 63 was the check for the early crop a

Shanyou 64 for the late crop. c*, ** = significant at the 5 and 1% level, respectively. dAccording to the nationstandard of high-quality rice in China, quality grade 1 = milling rate of brown rice >81% and that of polished rice >72%

half-transparent rice grain, length-width ratio is >3.0, and amylose content = 17-22%. Quality grade 2 = milling rate

content 79% and that of polished rice >72%, half-transparent rice grain, length-width ratio = 2.5-3.0, and amylos

Turant Dhan: a very early rice

variety released in Bihar, India

R. Thakur, A. K. Singh, R. S. Singh, and M.

Mishra, Rajendra Agricultural University,

Pusa 848125, Samastipur, India; and R. C.

Chaudhary, IRRI

Flood or drought periodically affects rice in

Biharespecially in the northern areas.

Sometimes floods and droughts occur at the

same time in different parts of the state.

Farmers require rice varieties that are

suitable for preflood and postflood condi-tions and for intermittent drought to enable

a harvest on the available rainfall.

Varieties that are very early-maturing arthe obvious choice for these situations.

Sattari, Prasana, and Heera, which all have

70-75 d durations and were released in

recent years, have not been accepted by

farmers because of their poor yield and

susceptibility to diseases and insect pests.

We began working to develop very early

rice varieties in the early 1980s. Numerous

early-maturing cultures from IRRI were

evaluated. A hybridization program was

undertaken that made use of available very

early germplasm.

Culture ES18-5-1, with 70-75 d dura-tion, was developed from the cross Sattari/

Rasi. The culture consistently outyielded

Table 1. Yields of ES18-5-1 in uniform varietal trials at different locations in Bihar, India. 1989-95

Year LocationYield (t/ha) (preflood)

ES18-5-1 Sattari Prasana Heera CV (%) LSD (5%

1989-90 Dhangain 3.1 2.3 1.4Pusa 2.4

12.6 0.4

1990-91 Dhangain 2.81.7 1.92.7 2.1

16.0 0.6

Sabour 2.2 1.9 1.211.9 0.819.9

Pusa 2.0 1.2 1.7 8.8 0.20.4

1991-92 Dhangain 3.1 2.2 1.1 15.4 0.3

Sabour 2.3 1.6 1.3 14.6 0.6Pusa

1992-93 Dhangain1.3 1.1 1.2 13.12.1 2.5

0.21.6

Sabour 1.90.6

1.2nsa

Pusa 2.61.0 1.1 11.1 0.2

1993-94 Bikramganj1.8

4.31.2 0.9 10.4 0.4

4.3 1.1Sabour 1.5 1.1

1.7 13.9 0.11.1 0.5 16.8 0.8

Pusa 3.8Patna

3.0 2.7 11.8 0.051.6

2.32.3

1994-95 Pusa1.4

2.90.5 ns

Pooled mean 2.52.0 13.8

2.0 1.5 1.20.6

ans = not significant.

IRRN 20:4 (December 1995) 1

Character




12/34

Table 2. Yield (t/ha) of ES18-5-1 in on-farm trials sown on different dates around Bihar, India.1991-95.

10 JulYear

ES18-5-1 Sattari Heera

1991-92 2.6 2.1 1.61992-93 3.6 2.3 1.51994-95 3.2 2.4 1.7Pooled mean 3.1 2.2 1.6

25 Aug (postflood)

ES18-5-1 Sattari Heera

2.4 1.5 1.13.4 2.1 1.2

2.7 1.8 1.3

2.8 1.8 1.2

check varieties in multilocation state

on-farm trials, ES18-5-1 outyielded checksThe pooled averages exhibited a 20.8%

Under late sown conditions (Aug 25) in1989 to 1994 under preflood conditions.

Prasana, and 41.7% over Heera (Table 1).uniform varietal trials (very early) from

yield increase over Sattari, 38.4% over

across 3 yr. Yield increases were as high as

133.3% over Sattari and 55% over Heera

(Table 2).

The culture was released as Turant Dhan

for preflood and postflood conditions as

well as for use under upland conditions. It is

a semidwarf (90-95 cm) indica with sturdy

stems. Turant Dhan has field resistance to

brown spot and bacterial blight and is

suitable for double cropping during the wet

season.

Purnendu, a new deepwater Performance of Purnendu in national trials in India. 1986-92.(50-100 cm) rice variety in eastern

IndiaYield (t/ha)

Year Trial/siteMaximum

water

1986 PVT-5a

S. Mallik, C. Kundu, S. K. B. Roy, S. D.

Chatterjee, and B. K. Mandal, Rice

Research Station (RRS), Chinsurah

712102, West Bengal, India

Patna, Bihar

Pusa, BiharGhagraghat, Uttar PradeshCentral Rice Research Institute

We developed the new variety Purnendu Chinsurah, West Bengal

(CN573-221-7-1) by pedigree selection

from the cross Patnai 23/Jaladhi 2.

Purnendu is suitable for intermediate and CRRI, Orissa

deepwater conditions where water is 50-

100 cm deep or more. CRRI, Orissa

across 36 locations in the national varietalPatna, BiharPusa, Bihar

testing program for several years. Its mean Sabour, Biharyield was 3.0 t/ha, with a potential yield of Ghagraghat, Uttar Pradesh

5.3 t/ha. The mean yield of Purnendu was

78% more than that of Tilakkachari acrossChinsurah, West BengalPatna, Bihar

8 locations, 38% more than that of Sabita Pusa, Bihar

across 17 locations, and 67% more thanSabour, BiharCRRI, Orissa

that of Jalamagna across 111 locations (see Pulla, Andhra Pradesh

1987 PVT-5

Pulla, Andhra PradeshChinsurah, West Bengal

1988 UVT-5b

Pulla, Andhra Pradesh

Pumendu was evaluated as IET10029 N. Lakhimpur, Assam

1989 UVT-5

Purnendu Standard depth

check (cm)

Tilakkachari3.6

2.42.0

(CRRI) 1.02.6

2.6 *e

5.1*

3.4*

2.3*

3.0*4.2

2.2

0.8*

2.61.7

4.2

3.9*3.8*4.53.4

3.4*

1.5

2.31.802.0

0.82.2

2.1

Sabita1.4

1.4

3.3

1.60.5

2.61.6

3.80.91.43.93.3

2.4

NAb

40

2590

100

7575

85

90

80

103

70

170

6064

5570507590

80

table). In national testing, it ranked first in

the 1987 preliminary variety trial-5 and

1989 UVT-6c JalamagnaN. Lakhimpur, Assam 4.07 3.42 110

Chinsurah, West Bengal 2.17* 0.62 65second in the 1989 uniform variety trial-6 Kamardanga, West Bengal 3.19* 1.41 65

and 1990 and 1992 advanced variety

trials-deepwater. It was approved for

release in 1994 in Orissa, West Bengal,

eastern Uttar Pradesh, Bihar, Andhra

Pradesh, and Assam.

Purnendu is strongly photoperiod-

sensitive and flowers around the end of

October. It has very good tolerance for

submergence with nominal elongation

(similar to that of FR13A) and good

kneeing ability. The variety possesses

resistance to sheath blight, yellow stem

Pusa, Bihar 2.67* 1.35 125

Pusa, Bihar 2.22* 1.61 95Chinsurah, West Bengal 1.80* 1.32 50

N. Lakhimpur, Assam 4.01* 3.12 100

Chinsurah, West Bengal 2.32* 0.50 70

Pusa, Bihar 2.70 2.16 NA

Motto, Orissa 3.42* 1.67 125Ghagraghat, Uttar Pradesh 4.73* 2.75 141

-

1990 AVT-DWd

1991 AVT-DW

1992 AVT-DW

aPVT-5 = Preliminary variety trial-5. bUVT-5 = Uniform variety trial-5. bNA = not available. cUVT-6 = Uniform variety trial-

6. dAVT-DW = Advanced variety trial - deepwater. e*Significantly superior to standard checks at the 5% level.


Integrated germplasm improvementflood-prone


13/34

borer, and leaffolder and moderate resist-

ance to sheath rot, brown spot, and gall

midge biotype 1.

about 3 mo. Grain is golden with purple

Purnendu has strong seed dormancy for

Jitendra, a new deepwater rice

variety for Uttar Pradesh and West

Bengal, India

S. Mallik, C. Kundu, S. K. Datta, B.

Banerjee, S. D. Chatterjee, and B. K.

Mandal, Rice Research Station (RRS),

Chinsurah, 712102, West Bengal, India

The Varietal Identification Committee of

the Indian Council of Agricultural Re-

search approved the release in 1994 of

Jitendra (SF432) for deepwater areas in

Uttar Pradesh and West Bengal, India.

Jitendra is a pureline selection from land

races. It was developed at RRS, Chinsurah.The variety is suitable for water depths of

100 cm or more.

The mean yield of the variety in

national trials was 2.8 t/ha with a yield

potential of 5.0 t/ha. It yielded 46% more

than Tilakkachari and 33% more than

Jalmagna. It ranked third in the 1992

advanced variety trial-deepwater (AVT-

DW), fifth in the 1991 AVT-DW, and

seventh in the 1990 AVT-DW over the

pooled means. At Ghagraghat, Uttar

Pradesh, Jitendra yielded 5 t/ha in 1989

with a maximum water level of 191 cm,and 4 t/ha in 1992 when the maximum

water depth was 141 cm (see table).

Jitendra is tall, photoperiod-sensitive,

and flowers around the third week of

October. It has tolerance for submergence,

mainly through elongation and very good

kneeing ability. Panicles are well exserted

with long slender golden grains and purple

apiculi. Grain dimension is 10.9 2.9 mm,

with a test weight of 31.2 g. Kernels are

white with a length-breadth ratio of 3.3.

Hulling percentage is 79.7 and milling

percentage is 72.5. The rice has intermedi-

ate alkali value (2.6) and amylose content

(25.0). Seed dormancy is about 3 mo.

Jitendra has resistance to neck blast,

brown planthopper, and whitebacked

planthopper and moderate resistance to

leaffolder and gall midge biotype 1.

apiculi. Mean grain dimensions are 7.9 and amylose content (26.1) are high.

2.8 mm with a test weight of 18.9 g. Kernels A large amount of seed has been

are white with a length-breadth ratio of 2.5. distributed through the minikit program to

Hulling percentage is 79.5 and milling make the variety available to farmers.

percentage is 73.5. Both alkali value (5.6)

Performance of Jitendra in national trials. India. 1988 -92.

Yield (t/ha)

Jitendra National checkYear Trial/site

1988 PVT-5a Tilakkachari

Chinsurah, West Bengal 1.2a

nil

Pusa, Bihar 1.0* nil

Ghagraghat, Uttar Pradesh 1.2 1.1

Canning, West Bengal 3.1 3.6

Maximum

waterdepth (cm

85140

70

90

1989 UVT-6b Jalmagna

Chinsurah, West Bengal 2.4 0.6 65

Ghagraghat, Uttar Pradesh 5.0 4.6 191

1990 AVT-DMc

Pusa, Bihar 1.7

Chinsurah, West Bengal 1.5Ghagraghat, Uttar Pradesh 3.0*

1.6 951.3 50

2.1 200

1991 AVT-DWPusa, Bihar 2.4 2.2 nae

1992 AVT-DW

Ghagraghat, Uttar Pradesh 4.0* 2.8 141

Motto, Orissa 2.4 1.7 125

aPVT-5 = Preliminary variety trial-5. b UVT-6 = Uniform variety trial-6. cAVT-DW = Advanced variety trial - deepwater.d* = significantly superior over national checks at the 5% level. ena = not available.

step is to evaluate their performance in

A simple method for producing F1hybrid seed for observational yieldtrials

B. C. Viraktamath and M. I. Ahmed, Hybrid

Rice Laboratory, Directorate of Rice Re-

search (DRR), Rajendranagar, Hyderabad

500030, Andhra Pradesh, India; C. X. Mao,

Hunan Hybrid Rice Research Center,

Changsha 410125, China

After good hybrid combinations are

identified in test-cross nurseries, the next

observational yield trials (OYT) before

promoting the promising ones to regional o

national trials.With the numerous hybrids that need to

be evaluated in OYT, it is often difficult to

get proper space isolation to produce pure

F1 seed at a research farm. However,

producing hand-crossed F1 seed of many

hybrids is laborious and often impractical.

To overcome these problems, a simple

method for producing a small quantity of

relatively pure F1 seed for conducting OYT

was developed.

1. Layout for production of

F1 seed for observational

yield trial.


Seed techonology


14/34

Proline concentration in rice seedlings cultivated under normal and stress conditions. a

Proline concentration (mg/g fresh matter)

Variety 7d 21 d

Control Stress % over control Control Stress % over control

PokkaliIR42MI 48

Perla

52.11 c58.98 b

45.03 d68.19 a

98.87 d106.00 c

156.68 a

153.28 b

189179

347224

66.10 c68.70 b

59.46 d71.10 a

117.60 d

163.27 b180.11 a

194.44 c

177237302

273

SE

CV(%)

+0.92

2.84

+0.540.72

+0.42

1.45

+0.880.93

a Values followed by dlfferent letters are significantly dlfferent at the 5% level according to DMRT.

Severe salinity stress induces numerous

metabolic irregularities in plants. Research-

ers have assumed that a large (up to 100

times the normal) accumulation of free-

proline is one of the most dramatic charac-

teristics of the stress.

We surface-sterilized 20 seeds for each

of four rice varieties: salt-tolerant Pokkali

and IR42 and salt-sensitive MI 48 and

Perla. After sterilization, these varieties

were grown in plastic pots filled with gravel

and Hoagland nutrient solution enriched

with 0.7% NaCl solution. Other seeds were

sown under the same conditions without

salts. A pH value of 5.0 was maintained for

both. Plants were placed in growth cham-

L. M. Gonzales and J. Labrada L., Soil

Science and Agricultural Chemistry Depart-

ment, Agricultural Research Institute "Jorge

Dimitrov," Bayamo 2360, Cuba

All of the restorer lines of the hybrids to

be produced are sown on the same day.

Seedlings for each are transplanted 25-30 d

after sowing within a 1-m2 area, and spaced

at 15 15 cm in alternate rows, leaving a

20-cm space all around the edge. The A

lines of the hybrids to be produced are sown

2. Position of A () and

R (x) lines in an isolated

chamber.

on five or six different dates at a 6- to 7-d

interval starting 2 wk before the seeding of

the R lines. The aim is to achieve proper

synchronization for the different A and R

lines.

At the boot leaf stage of R lines, 2-m-

high barriers are erected on three sides of

the 1-m2 plots, leaving a gap of 20 cm from

the ground (Fig. 1). The open side is

partially covered by the bamer from the

adjacent plot. This space can be conven-

iently used for cultural operations, includ-

ing supplementary pollination. Just before

panicle emergence of the R lines, plants of

the desired A line, which are at the same

growth stage as the R lines, are moved and

planted in the vacant alternate rows. To

ensure higher outcrossing, supplementary

pollination using a stick should be carried

out at anthesis 3-4 times/d for a week.

Within each 1-m2plot, there are 15

plants of the R line in 3 rows and 10 plants

of the A line in 2 rows (Fig. 2). With a very

conservative estimate of only 5 tillers/plant

of the A line, 80 spikelets/panicle, and only

a 40% outcrossing rate, about 1,600 seeds

weighing 30-35 g can be easily obtained.

are more than adequate. The method

proposed can be used to produce many

hybrids for OYT. The advantages are

comparatively pure seed of numerous F1hybrids can be produced in a limited

area,

the problem of obtaining proper syn-

chronization of parental lines in hybrid

seed production can be easily overcome,

and

F1 seed for conducting OYT can be

produced with the very limited quantityof R line seed available initially.

For conducting an OYT, 20-25 g of seed


Proline content in rice seedlings

grown under saline conditions

bers with 30/25 C day/night temperature,

14 h of light, and 70% relative humidity. The

experiments were laid out in a randomized

block design with three replications across

three seasons. All measurements were taken

7 and 21 d after transplanting.

Plant material (0.5 g) was homogenized

in 10 ml of 3% aqueous sulfosalicylic acid

solution and filtered. Two ml of filtrate were

reacted in 2 ml acid-ninhydrin and 2 ml of

glacial acetic acid for 1 h at 100 C. The

reaction was terminated in an ice bath. To the

reaction mixture, 4 ml of toluene were added

and mixed vigorously with a test tube stirrer

for 15-20 s. The cromophone containing

toluene was aspirated from the aqueous

phase, warmed to room temperature, and the

absorbance read at 520 nm using toluene for

a blank.

The proline concentration was deter-

mined from a standard curve and calculatedon a fresh weight basis as

mmol proline/g fresh weight material=

[(mg proline/ml* ml toluene)/115.5 mg/mmol]/

[(g sample/5]

The proline content for all varieties

exposed to salt stress significantly increased

(see table). The highest proline concentra-

tions were observed in salt-sensitive varieties


Physiology and plant nutritionPhysiology and plant nutrition


15/34

Perla and MI 48 (between 224 and 347%

more than the control at 7 d and 273 and

302% at 21 d). Pokkali and IR42 showed

proline values of 179-189% more than the

control at 7 d and 177-237% at 21 d.

Photosynthetic rate and respiration

of some F1 hybrid rices

M. J. Baig, P. Swain, S. B. Pradhan, P. J.

Jachuck, and K. S. Murty, Central Rice

Research Institute, Cuttack 753006, India

We studied the photosynthetic rate (Pn) and

maintenance respiration (MR) of 11 hybrids

developed from five cytoplasmic male

sterile (CMS) lines (IR64A, PMS3 A, V20A, Deepa A, and PMS 10 A) and their

corresponding pollen parents under field

conditions during the 1992 wet season.

The experiment was laid out in a

randomized complete block design withthree replications. Seedlings were trans-

planted at a spacing of 15 15 cm in 3-m2

plots in the main field. Sixty kg N/ha were

applied. We measured the Pn of the second

The trials indicated that the salt-tolerant

varieties do not necessarily accumulate

large amounts of free- proline relative to

salt-sensitive varieties. In general, free-

proline content increased in salt-sensitive

(n-1) leaf 35 dafter planting (DAP) and thatof the flag leaf (n leaf) at flowering with a

LI-6000 photosynthesis system at near

saturated light (1,000 E/m2per s).

directly from the CO2 evolution rate using a

differential respirometer (Gilson, USA).

Leaves were excised in the evening and kept

in the dark for 12 h. A weighed quantity

without the midrib was cut into 1-2 mm

pieces and suspended in 1.8 ml of 0.2 M

phosphate buffer at pH 7.0 in a Warburg

flask. Twenty percent KOH (0.2 ml) was

poured into a center well and a filter paper

strip was added to the alkali to increase the

surface area for rapid CO2 absorption. Aftergreasing the upper rim, the flask was

attached to the manometer, and the side arm

of the flask was closed with a plug. The

flask was then immersed in a water bath at a

Maintenance respiration was measured

varieties compared with that in salt-tolerant

varieties and thus may not always be a

suitable marker in examining salt resistance

in rice.

constant 30 C. The system was shaken to

promote rapid gas exchange between the

fluid and the gas phase.

The manometer fluid fell, indicating the

rapid consumption of oxygen in the

chamber by the tissue. The rate of respira-

tion was calculated by subtracting the initia

reading from the final reading. At each

growth stage, four measurements for both

Pn and MR were taken per sample for all

three replications. The yield and biomass

were assessed at harvest (see table).

MR among the hybrids and parents were

observed at both 35 DAP and at flowering.

However, the means of these three param-eters were generally higher at flowering

than at 35 DAP and in hybrids than in male

parents at flowering stage. Hybrid IR64 A/

Rasi showed high Pn at 35 DAP while IR64

Significant variations in Pn, MR, and Pn

Photosynthetic rate (Pn) and maintenance respiration (MR) in relation to yield and biomass production in rice hybrids. Cuttack, India. 1992 wet season

35 DAPa Flowering

Hybrid/restorer Pn Pn TDMb Yield

(mol CO2/m2) MR/s Pn/MR (mol CO2/m

2) MR/s Pn/MR (g/m2) (g/m2)

Hybrids

IR64 A/Savitri 14.8 3.9 3.8 26.0 2.3 11.1 981 401

PMS3A/Saruchina 21.0 2.0 10.6 28.9 2.4 12.1 1035 538

V20 A/IET11057 19.9 2.1 9.3 21.7 2.8 7.7 816 361

Deepa A/IET11057 22.5 2.8 8.1 21.1 2.6 8.1 916 312

V20 A/IET10463 15.3 2.1 7.5 17.2 2.5 6.9 676 263

PMS10A/ARC10339 16.0 2.3 7.0 27.6 3.7 7.4 865 463

IR64 A/Rasi 26.5 2.5 10.6 20.0 2.5 7.9 616 246

IR64 A/Miz. 51 16.7 1.8 9.2 29.7 3.2 9.2 1001 436

PMS3A/IR9828-

91-

2-

3 16.2 2.4 6.7 20.2 2.0 10.3 798 396

IR64 A/lR25560-109-3-1-3-2 16.2 2.3 7.2 17.0 2.3 7.5 694 212

IR64 A/IR1846-300-1 23.8 2.3 10.3 20.8 2.8 7.5 814 316

Restorers

Savitri

SaruchinaIET11057

IET10463

ARC10339RasiMiz. 51

lR9828-91-2-3

lR25560-109-3-1-3-2

lR1846-300-1

Grand mean

Mean of hybrids

Mean of restorers

22.7

18.9

14.116.621.0

8.121.117.1

30.2

18.1

18.9

19.0

18.9

2.3

2.4

4.52.12.7

2.02.32.0

2.91.9

2.5

2.4

2.3

9.7

7.83.28.07.7

4.18.49.1

10.4

9.5

8.0

8.2

7.8

29.0

31.618.6

17.612.8

9.516.819.8

25.1

20.1

21.5

22.7

20.1

3.3

2.32.0

2.61.6

1.83.02.7

3.2

2.7

2.7

2.8

2.5

8.8

13.79.4

6.77.7

5.25.67.4

7.9

7.6

8.4

8.77.3

1121

863912

921729

961693942

746

964

860

837

885

412

346402

342240

424262421

242

341

359

343

351

CD at 5% 3.6 0.8 1.5 1.5 0.3 0.8 29 14

a DAP = days after planting. b TDM = total dry matter.



16/34

A/Miz.51 and PMS3 A/Saruchina were

more efficient at flowering. PMS3 A/

Saruchina recorded the highest total dry

matter (12.1 t/ha) and grain yield (538 g/m2)

Integrated effect of deeply placed

urea and Gliricidia green manure on

grain yield of transplanted rice

S. S. Dhane, R. R. Khadse, and H. K. Pawar,

Regional Agricultural Research Station

(RARS), Karjat, Konkan Krishi Vidyapeeth,

Dapoli, Maharashtra 410201, India

We studied the integrated effect of organic

and inorganic sources of N on grain yield of

rice variety PLG-1 (130 d duration) during

1991-93 wet seasons. We compared how

deeply placing urea behind the plow and

applying Gliricidia sepium leaves as agreen manureindividually and in

combinationaffected rainfed transplanted

rice.

experiment was laid out in a 50-m2plot on

the RARS farm in a randomized block

design with three replications. The soil was

clay loam with pH 7.4 (1:2.5 soil:water) and

a cation exchange capacity of 35 meq/100 g

soil. All of the plots received 21 kg P/ha as

single superphosphate and 41 kg K/ha as

potassium chloride.

Prilled urea (PU) (25 kg N and 50 kg N/ha) was applied behind the plow, about 5-6

cm deep, at the time of puddling. Gliricidia

was spread uniformly over newly puddled

soil as fresh green manure at 5 and 10 t/ha

(containing 2.7% N on an oven-dry basis)

Each of the nine treatments in the

Effect of integrated

use of inorganic and

organic N on grain

yield of rice. Maha-

rashtra, India.


followed by IR64 A/Miz.51. Photosynthe- Unlike PMS3 A/Saruchina, high Pn

is at flowering, however, was positively coupled with low MR and high Pn/MR are

correlated with total dry matter (r= 0.430*) desirable for high photosynthetic productiv-

and grain yield (r= 0.446*) at harvest. ity, which ultimately leads to more grain.

Effect of deeply placed urea behind the plow and Gliricidiagreen manure on grain yield of trans-

planted rice. Maharashtra, India. 1991-93 wet seasons.

Treatment Mean grain yield (t/ha)

Urea N Green manure 1991 1992 1993 Pooled mean

(kg/ha) (t/ha) (kg N/ha)

0 0 0 4.0 2.2 3.7 3.325 0 0

50 0 04.9 2.8 4.4 4.0

0 54.5 3.9 3.9 4.1

31.5 5.0 4.2 3.90

2.510 63.0

254.8 3.0

5 31.54.8 4.2

5.2 3.5

254.8

104.5

63.0

50

4.9 3.9 5.1 4.6

550

31.510

5.0 4.6

63.04.7

5.44.8

4.8 5.5 5.2

LSD (0.05) nsa 0.4 0.4 0.1

ans = not significant.

and pressed below the surface by hand.

Three-week-old rice seedlings were planted

at 20- 15-cm2 spacing during the wet

season on 24 Jul l991,20 Jul l992, and19 Jul l993 and harvested on 10 Nov 1991,

5 Nov 1992, and 3 Nov 1993.

The response of the rice crop to the

different treatments varied significantly

with the season (see table). Applying

Gliricidia at 5 or 10 t/ha coupled with the

deep placement of urea at 25 or 50 kg N/ha

Effect of rice hull, biofertilizer, and

chemical fertilizers on growth and

nitrogen economy of wetland rice

increased rice grain yield significantly over

applying Gliricidia alone. The maximum

yield of 5.2 t/ha, which was significantly

higher than the rest, was obtained by

applying Gliricidia at 10 t/ha and urea at 50

kg N/ha (see table, figure). Thus, the

integrated use of inorganic and organic

nitrogen can make important contributions

to increasing and sustaining rice produc-

tion.

Effect of integrated use of biofertilizer and chemi-

cal fertilizer N on yield of Pusa Basmati 1. IARI,

New Delhi, India. 1992 wet season.

T. K. Biswas, National Facility for Blue-Green TreatmentGrain yield (t/ha)

Algal Collection, Indian Agricultural Research Rice hull- Untreated

Institute (IARI), New Delhi 110012, India;amended field field

and R. N. Garg, Agricultural Physics Depart- Control 3.5 3.4

ment, IARl Blue-green algae (BGA) 3.9 3.8Leucaena 4.9 4.7

Urea (30 kg N/ha)We studied the effects on rice yield of using Urea (60 kg N/ha)

3.8 4.04.4 4.1

leucaena ( Leucaena leucifera), a common Urea (120 kg N/ha) 5.1 5.0

leguminous plant in northern India; blue-Urea (30 kg N/ha)

Leucaena + BGA 4.9 4.7

green algae (BGA); and ureaindividually BGA 4.6 3.9

and in combinationin a mild alkaline soil Urea (60 kg N/ha) 5.0 4.8

with and without rice hull amendment.+ BGA

The soil was sandy loam (mixed,1/2 Leucaena + urea 5.2 4.7

Isohyperthermic Typic Ustocrept) with pH 1/2 Leucaena + urea 5.4 5.0

8.0, EC 4.2 dS/m, 22 kg ESP, CEC 15CD (0.05)

cmolc/kg, and 0.46% organic C. Rice hull0.4 0.5

(0.56% N on an oven-dry basis) was Pooled mean 4.6 4.3

incorporated at 5 t/ha (about 22 kg N)

(60 kg N/ha)

(90 kg N/ha)

CD (0.05) (0.7)

Fertilizer managementFertilizer management


17/34

More green biomass was obtained whe

S. rostrata seedlings were planted at 15 cm

spacing and incorporated 45 DAP than witthe other treatments. When compared with

the no-GM control, the yield increase with

this method was 38.4% more in 1992-93

and 44.5% more in 1993-94. Because of it

initial slow growth rate, S. speciosabioma

was lower than that ofS. rostrata. Incorpo-

rating green biomass in the standing

ricefield positively increased the yield

parameters of panicle number, panicle

length, and filled grains per panicle,

resulting in higher rice yield (see table).

Wet seeded rice benefits from

intercropping 20-d-old S. rostrata seed-

lings at intrarow spacing of 15 cm and

incorporation at 45 DAP.

during land preparation at the IARI farm

during the 1992 kharif (wet) season. Fresh

leucaena (2.3% N on an oven-dry basis) was

chopped into 2-3 cm lengths and incorpo-

rated at 30 t/ha (about 90 kg N) 3 d before

transplanting. Soil-based inocula of BGA

( Aulosira, Tolypothrix, Scytonema, Nostoc,

Anabaena, and Plectonema) at 30 kg/ha

were broadcast at 8 d after transplanting

(DT) on standing water. Prilled urea was

applied in three splits at transplanting, 35

DT, and at flowering.

Pooled data showed that rice hull did not

significantly increase the grain yield of Pusa

Basmati 1, although a constant increase in

grain yield was obtained by adding rice hull

regardless of different BGA, leucaena, and

prilled urea treatments (see table). BGA and

urea at both 30 and 60 kg N/ha had

synergistic effects in fields that received

rice hull. In untreated fields, a synergistic

effect was observed only for urea at 60 kg N

and in BGA treatments.

The significant yield increase achieved

with BGA and urea combinations when

compared with similar levels of urea alone

suggests that a starter dose of fertilizer N is

important for establishing BGA in mild

alkaline soil. Results revealed that BGA

contributed about 30 kg N/ha when applied

with urea to plots where rice hull was

added. No such synergistic effect was

noticed with the leucaena and BGA

combination. However, cuttings of leucaena

increased rice yield by more than 1 t/ha,

with or without rice hull.

In northern India, sandy loam soils with

low organic matter content are generally

poor, both physically and in N status. Rice

has been grown increasingly in this region

during the past three decades, with burning

of hulls near rice mills a common practice.

Instead, hulls could be applied on the fields

to improve the overall soil physical propert

and organic matter status. We suggest that

farmers should apply rice hulls, combined

with leucaena and BGA, to substantially cu

down on costly fertilizer N use while

improving the soil.

Influence of intercropping green

manure in wet seeded rice

P. Jayapaul, B. Uthayakumar, and S.

Purushothaman, Agricultural College and

Research Institute (ACRI), Tamil Nadu

Agricultural University, Madurai 625104,

Tamil Nadu, India

The effects of incorporating intercropped

green manure (GM) in wet seeded rice

cultivated during 1992-94 were studied at

ACRI.

as Typic Ultisol. The initial nutrient status

was 233 kg N/ha, 17.1 kg P/ha, and 246 kg

K/ha in 1992-93 and 226 kg N/ha, 16.2 kg

The soil was a sandy clay loam classified

P/ha, and 244 kg K/ha in 1993-94. Sesbania

rostrata usually has delayed germinationwhen sown under puddled conditions. so

instead, it was raised separately and 20-d-

old seedlings were planted. Seeds of S.

speciosa were dibbled at 3 kg/ha.

Five days after IR20 was sown, both

GMs were intercropped in the main field in

the empty space of 30 cm and maintained at

a 1.5-m interval. Intrarow spacings of 15

and 30 cm and incorporation at 30 and 45 d

after planting (DAP)/sowing for the GMs

were compared with a no-GM control in a

randomized block design with three

replications. Fresh green biomass was

assessed at incorporation.

Effect of intrarow spacing and time of incorporation of green manure on biomass production, yield parameters, and yield of wet seeded rice. ACR

Madurai, India. 1992-94.

Treatments 1992-93 1993-94

Green manure lntrarow Time of Fresh N Panicles Panicle Filled Grain Fresh N Panicles Panicle Filled Grai

spacing incorporation green input (no./hill) length grams/ yield green input (no./hill) length grains/ yield

(cm) (DAP) a biomass (kg/ha) (cm) panicle (t/ha) biomass (kg/ha) (cm) panicle (t/ha

(t/ha) (no.) (t/ha) (no.)

Sesbania rostrata 15

153030

Sesbania speciosa 15

15

30

30

No green manure -CD (P = 0.05)

a DAP = days after planting.

30 1.30 42.9 8.0 18.2 90.0 3.96 1.23

45 1.64 53.5 8.0 18.391.1 4.04 1.50

30 1.05 34.8 7.8 18.2 88.0 3.61 0.88

45 0.76 25.4 7.4 18.0 85.1 3.51 0.73

30 0.14 3.6 7.2 17.7 83.3 3.31 0.13

45 0.18 4.5 7.2 17.6 83.2 3.22 0.18

30 0.07 1.9 7.2 17.4 83.1 3.04 0.06

45 0.09 2.5 7.0 17.4 83.1 2.98 0.08

7.0 17.0 80.1 2.92 -ns 0.2 0.9 0.17 -

38.7 7.4 17.3 87.1 3.5949.2 7.6

17.388.2

3.8029.4 7.0 17.0 87.1 3.5124.5 6.8 17.1 86.2 3.51

3.4 6.4 16.8 85.2 3.22

4.5 6.4 16.8 85.1 3.101.6 6.2 16.2 83.1 2.92

2.3 6.0 16.2 82.5 2.87

4.8 16.0 78.3 2.630.8 0.7 0.2 0.40


Fertilizer management-organic sources

- - -

- --

-

Fertilizer management-organic sources


18/34

Late planting ofsali (rainfed lowland

winter) rice is common in many parts of the

Effect of hill density, seedling

number/hill, and potassium on late

transplanted sali (rainfed lowland

winter) rice yield in Assam, India

J. K. Choudhary, R. K. Thakuria, and G. R.

Das, Regional Agricultural Research Station,

Assam Agricultural University, Karimganj

788710, India

BarakValley zone (Cacher, Karimganj, and

Hailakandi districts) of Assam, India.

because of flooding during July and August,

the normal planting time. Yields are usually

low under late planting because of poor

tillering and reduced panicle size, resulting

from progressive drought and low soil K

status. Managing the optimum plant

population and K status seems to be

Table 1. Effect of hill density, seedlings per hill, and K levels on productive tillers/planta and grain

yield (t/ha)b of lateplanted sali rice. Assam, India. 1992-93.1 seedling/hill 2 seedlings/hill

Hills/m23 seedlings/hill

(no.) 20 kg 40 kg 20 kg 40 kg 20 kg 40 kgK/ha K/ha K/ha K/ha K/ha K/ha

33

50

66

CV (%)

33

50

66

CV(%)

2.4 e

(5)

2.2 f(6)2.5 e

(6)3.09

3.3 ef

(7)3.0 g

(8)3.1 fg

(7)3.74

(6)

2.5 e

2.2 f(6)2.4 e

(6)

3.1 fg

(7)3.4 de

(8)3.1 fg

(7)

1992

2.7 d

2.7 d

2.7 d

(6)

(7)

(5)

1993

3.4 de

(7)3.8 bc

(8)3.0 g

(7)

(7)

2.8 cd 2.9 bc

(7)

2.8 cd 3.0 ab(7) (8)2.7 d 2.9 bc

(6) (6)

3.5 de 3.6 cd

(8) (8)4.0 ab

(9)

4.1 a

(11)3.3 ef 3.5 de

(8) (7)

3.1 a

(8)

2.9 bc(7)2.9 bc

(6)

4.1 a

(10)3.8 bc

(8)3.8 bc

(8)

aNumbers in parentheses are not significantly different. bWithin a year, means either in a column or row followed by

the same letter are not significantly different (P=0.05) by DMRT.

Table 2. Grain yield (t/ha) of late-planted rice (KMJ1-52-3) as affected by the interactions of hill den-

sity (HD) seedlings/hill (SH) and HD Ka. Assam, India. 1992-93.

Seedlings per hill K (kg/ha)

HD (no./m2)

1 3 5 Mean 20 40 Mean

33 2.5 d50 2.2 e66 2.5 d

Mean 2.4

33

50

3.2 c

66 3.2 c3.1 c

Mean 3.2

HD SH means

HD K means

2.8 b2.8 b2.7 c

2.7

3.5 b

3.9 a3.2 c

3.5

1992

0.1

0.08

3.0 a3.0 a2.9 a

3.0

3.9 a

3.9 a3.7 a

3.8

1992

2.8 2.7 b 2.8 a 2.82.7 2.7 b 2.6 c 2.72.7 2.7 b 2.7 b 2.7

2.7 2.7

1993

3.5 3.4 b 3.6 a 3.5

3.7 3.7 a 3.7 a 3.73.3 3.2 c 3.4 b 3.3

3.4 3.6

1993

0.20.13

a Within a year and an interaction, means either in a row or a column followed by the same letter are not signifi -

cantly different (P = 0.05) by DMRT.


imperative for stabilizing yield under these

conditions.

We studied the effect of hill density

(HD), seedlings/hill (SH), and K levels on

late-plantedsali rice yield during 1992-93.

The experiment was laid out in randomized

complete block design (factorial) with three

replications. Eighteen treatment combina-

tions of HD (33,50, and 66 hills/m2maintained at spacings of 20 15 cm,

20 10 cm, and 15 10 cm, respectively),

SH (1, 3, and 5), and K levels (20 kg/ha and

40 kg/ha) were tested. Bunds were con-

structed to separate the 24-m2plots.

The soil was clay loam with pH 5.1,

0.87% organic C, 22 kg available P/ha, and

94 kg available K/ha. Fifty-day-old

seedlings of KMJ1-52-3, a photoperiod-

sensitive, semidwarf cultivar, were planted

on 25 Sep. Recommended doses of N (40

kg/ha), P (20 kg/ha), and K (per treatment)

were applied basally. Rice yield wasrecorded at 14% moisture.

The crop duration was 145-146 d. The

treatments involving 33 hills/m2, 5 SH and

40 kg K/ha, and 50 hills/m2, 5 SH, and 20 kg

K/ha recorded the best yields (Table 1). The

increased productive tillers/plant at 33-50

hills/m2 at 5 SH probably resulted in the

better yield performance, although in 1993,

50 hills/m2, 3 SH, and 40 kg K/ha produced

equally good yields.

The main effects of HD and SH were

significant in both years, but for K, in 1993

only (Table 2). Grain yield increased

significantly when HD was 33 hills/m2 in

1992 and 50 hills/m2 in 1993. In both years,

yield increased progressively with increase

in SH from 1 to 5. The interaction between

HD and SH was significant because the

treatments involving 5 SH, irrespective of

HD, outyielded the rest except for 3 SH and

50 hills/m2 in 1993.

Forty kg K/ha recorded a significant

yield increase over 20 kg K/ha in 1993. But

HD K interaction was significant in both

years, and the treatment involving 33 hills/

m2 and 40 kg K/ha outyielded the others in

1992. In 1993,50 hills/m2, either at 20 or 40

kg K/ha, yielded at par with 33 hills/m2 and

40 kg/ha K. The interaction, HD SH K,

however, was significant in both years.

Though rainfall was greater in 1992

(903.4 mm) than in 1993 (771.3 mm), less

rain during Nov-Dec 1992 (10.8 mm)

compared with 1993 (30.4 mm) made a

LSD(0.05)

Crop managementCrop management


19/34

difference in the soil moisture status

between the years. This might have been the

reason for the differential response to K.

Plants were adversely affected during the

reproductive and grain-filling stages due to

moisture stress, resulting in yield loss,

particularly in 1992.

Higher yields of late-planted sali rice

may be achieved by planting 5 SH at 33-50

hills/m2. Further investigation is needed

regarding K application.

Monitoring variation in brown

planthopper biotype in Guangdong,

China

Zhang Yang, Tan Yujuan, Huang Bingchao,

Plant Protection Research Institute,

Guangdong Academy of Agricultural Sci-

ences, Guangzhou 510640, China

It is important to monitor the variation in

brown planthopper (BPH) biotype when

breeding resistant varieties. We have beendoing this work since 1979 in Guangdong,

China, including yearly testing of BPH

biotype variation in Guangzhou and

conducting a biotype test with BPH

populations in Guangdong Province.

We used the seedling bulk test for all of

the BPH biotype-monitoring studies. The

population for the yearly test of BPH

biotype variation was collected from laterice in the field in Guangzhou. The insects

were reared on a BPH-susceptible variety

the greenhouse and tested the following

year. The BPH population for the biotype

test in Guangdong was collected from

Lechang (northern Guangdong), Xinxing

(western Guangdong), and Gaozhou

Guangzhou, Xinhui (central Guangdong)

(southwestern Guangdong) in June and Ju

of every year and tested the same year.

Seven BPH-resistant varieties (Table 1) an

susceptible check TN1 were evaluated

using the Standard evaluation system for

rice.

In the yearly test of BPH biotype

variation in Guangzhou, IR26 had the

highest damage score of the varieties

including Mudgo, which has the same

resistance gene. IR26 was found to be

susceptible to BPH in 1992 and 1993 with

score of 7. The score of Mudgo also

increased over time. IR36, ASD7, RathuHeenati, Babawee, and PTB33 had low

Table 1. Results of biotype test of BPH population of Guangzhou,China.Damage scale of varietiesa

Year TN1 IR26 Mudgo IR36 ASD7 Rathu Heenati Babawee PTB33

None Bph 1 bph 2 Bph 3 bph 4 bph 2+Bph 3

1979 9.0 1.0 1.1 1.2 1.0 1.01980 9.0 2.8 1.0 1.0 1.0 1.0 1.0 1.0

1981 9.0 6.7 3.0 1.0 1.0 1.0 1.0 1.01982 9.0 6.6 2.9 5.1 1.1 3.0 3.0 1.01983 9.0 4.5 1.2 1.0 1.0 1.0 1.0 1.01984 9.0 3.3 1.0 3.3 1.0 1.0 1.0 1.01985 9.0 3.2 1.1 1.0 1.0 1.0 1.01986 9.0 1.1 1.1 1.0 1.2 1.0 1.0 1.01987 9.0 2.9 3.3 1.2 1.1 1.01988 9.0 5.1 1.0 1.4 1.0 1.01989 9.0 6.8 1.0 3.4 3.1 3.0

1991 9.0 5.2 5.1 3.1 1.0 3.0 3.01992 9.0 7.0 8.8 3.0 5.2 1.0 5.0 1.01993 9.0 7.1 4.9 3.2 1.0 1.0 3.0 1.0

1990 9.0 4.9 2.5 2.5 3.2 1.0 3.0

aAv of 3 replications.

Table 2. Results of biotype test of BPH population of Guangdong, China.a

Location

Variety Year

Guangzhou Xinhui Lechang Gaozhou Xinxing Shantou Huiyang

1992 7.7 (1.6) a 7.6 (1.2) ab 9.0 (0.0) a 8.9 (0.2) a 8.3 (0.7) a 8.3 (0.7) ab 8.4 (0.5) TN1 1993 7.8 (0.9) a 9.0 (0.0) a 9.0 (0.0) a 9.0 (0.0) a 9.0 (0.0) a 9.0 (0.0) a 9.0 (0.0)

1994 8.8 (0.3) a 9.0 (0.0) a 9.0 (0.0) a 8.6 (0.7) ab 8.8 (0.2) a

1992 6.8 (1.3) b 6.4 (2.2) bc 8.7 (0.3) a 7.4 (1.3) c 7.9 (1.4) ab 7.6 (1.0) bc 4.7 (1.5) IR26 1993 6.8 (0.8) b 9.0 (0.0) a 8.9 (0.2) a 9.0 (0.0) a 7.2 (1.7) bc 8.6 (0.6) a 8.7 (0.3)

1994 7.4 (1.2) ab 8.3 (0.7) a 8.9 (0.2) a 8.7 (0.5) a 8.2 (0.3) a

1992 4.9 (1.9) cd 4.0 (0.4) d 5.0 (2.3) c 5.3 (1.2) d 5.4 (1.7) d 6.7 (1.2) c 6.7 (1.6) Mudgo 1993 5.9 (0.2) bc 6.6 (0.2) b 8.2 (0.9) ab 8.7 (0.0) a 5.4 (0.5) d 6.5 (0.8) c 8.7 (0.6)

1994 4.9 (1.7) c 8.8 (0.3) a 7.5 (1.1) b 7.8 (1.4) bc 5.9 (1.0) cd

1992 3.1 (0.2) e 1.2 (0.2) e 1.5 (0.5) de 1.0 (0.0) e 1.7 (0.7) g 1.8 (1.3) de 4.9 (0.2) IR36 1993 2.7 (1.5) ef 5.6 (1.1) c 1.9 (1.0) d 4.1 (0.6) d 2.3 (1.2) fg 2.3 (1.2) d 3.0 (1.5)

1994 3.8 (1.1) de 5.0 (2.1) cd 7.0 (0.8) b 4.7 (1.7) d 4.8 (1.3) de

1992 1.0 (0.0) g 1.1 (0.2) e 1.0 (0.0) e 1.0 (0.0) e 1.0 (0.0) g 1.0 (0.0) g 2.3 (1.5)dASD7 1993 1.0 (0.0) g 1.5 (0.9) e 1.0 (0.0) e 1.0 (0.0) e 1.0 (0.0) g 1.0 (0.0) g 1.1 (0.2)

1994 1.1 (0.2) fg 7.8 (0.6) a 3.8 (0.6) c 3.8 (0.7) d 3.7 (0.6) ef

1992PTB33 1993

1.3 (0.6) f 1.0 (0.0) e 1.0 (0.0) e 1.0 (0.0) e 1.0 (0.0) g 1.0 (0.0) g 3.4 (1.4)

1994 1.8 (1.2) f 1.7 (0.8) e 2.3 (1.2) d 1.2 (0.4) e 1.1 (0.2) g1.0 (0.0) g 1.3 (0.6) e 1.5 (0.6) d 1.0 (0.0) e 1.0 (0.0) g 1.0 (0.0) g 1.0 (0.0)

aMeans are the av of 3 replications and are compared by LSD test. Means (SD) within each column with the same letter are not significantly different (P>0.05).



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20/34

scores and were resistant to BPH, but IR36,

ASD7, and Babawee had higher scores in

some years.

2), most of the scores for IR26 were more

than 7 across the different locations and

years, with some not significantly different

from those of TN1. Mudgo scores ranged

from 4.0 to 8.8, showing its tendency to be

In the biotype test of Guangdong (Table

susceptible. TR36 and ASD7 scores were BPH biotype 1 dominated the population

higher than those of PTB33. The two before 1989, but in recent years it seems

varieties were particularly damaged by that BPH biotype 2 dominates with BPH

BPH populations in Xinhui in 1994, biotype 3 mixed into the population.

Gaozhou in 1993, and Lechang in 1994. Sources of resistance to these two BPH

PTB33 was resistant to every BPH popula- biotypes should be considered for use in

tion. BPH-resistance breeding.

biotype has been changing in Guangdong.

The results indicate that the BPH

Loss of harvested rice due to

rodents in central India

M. Thomas and R. Pachori, AICRP on Rodent

Control, Entomology Department, Jawaharlal

Nehru Krishi Vishwa Vidyalaya, Jabalpur

482004, India

During Oct to Nov in much of central India,

harvested rice is stacked up to 6 m high incircular (3-7.6 m diam) heaps on threshing

floors. A threshing floor, which covers 0.1-

0.5 ha, is prepared in the field by leveling

the ground and then compressing and

plastering it with cow dung; size depends on

the number of farmers involved and on their

holding sizes.

Rice often remains heaped for 2-3 mo before threshing because immediately after

the harvest, farmers are busy preparing their

fields and sowing the next crop. Limited

food and shelter in the harvested fields and

disturbances during the preparation force

most of the field rodents to move to other

places. Some settle under the rice heaps.

causing severe damage to the harvested

rice. During threshing, they move to the

new crops in the field.

We assessed the loss of harvested rice torodents and their burrow patterns under

heaps in five villages (see table) of central

India. Five threshing floors were surveyed

in each village; all were found to be infested

with Bandicota bengalensis and Millardia

meltada meltada with the former predomi-

nating, B. bengalensis constructed 1.2- to

3.9-m long labyrinth-like burrow systems

under the heaps. The burrows were like

Loss to rodents of harvested rice on threshing floors. Central India.

Burrow dimension

Village Threshing

months

Amarpur Jan-Feb

Poudikhurd Jan

Tamoria Dec-Jan

Dhanpuri Dec

Sitasarovar Jan-Feb

Heaps/threshing

floor (no.)

13

11

9

11

10

Burrows/

threshing

floora (no.)

47

(3.6)29

(2.6)13

15(1.4)

35(3.5)

(1.4)

Length

(m)

3.5

1.2

1.8

2.6

3.9

Depth Hoarded grain/ Rodent

(cm) threshing floor species

(kg)

20.7 10.2 B. bengalensis

0.8b

15.5 4.8 B. bengalensis0.4b


0.3b

19.30.2b1.6 B. bengalensis


1.4 b M. meltada

a Figures in parentheses are burrow densities/heap. b Hoarded grain/burrow.

Burrows of Bandicota

bengalensis Gray

under rice heaps onthreshing floor.

open canals (see figure). Underground

tunnels were rarely observed. The mean

burrow depth varied from 15.5 to 21.4 cm;

food chambers were located within. The

burrow depths under rice heaps were less

than those found in fields and along bunds.

The burrow density (no. of burrows no

of heaps) was the least (1.4) in Tamoria and

Dhanpuri villages, where threshing was

completed by early January. It was greatest

(3.6) in Amarpur and Sitasarovar wherethreshing lasted into February. The burrow

density increased as threshing was delayed.

Hoarding loss due to rodents in early

threshed areas was 1.6 kg grain/threshing

floor and 13.4 kg grain/threshing floor in

late threshed areas.

Farmers are advised to avoid late

threshing to minimize the loss of harvested

rice to rodents.


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International Rice Research Notes Vol.20 No.4

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