International Rice Research Newsletter Vol.13 No.2

8/4/2019 International Rice Research Newsletter Vol.13 No.2

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IRRN GUIDELINES

The International Rice Research

Newsletter objective is:

To expedite communication among

scientists concerned with the

development of improved technology

for rice and for rice-based cropping

system. This publication will reportwhat scientists are doing to increase

the production of rice. inasmuch as

this crop feeds the most densely

populated and land-scarce nations in

the world . . . IRRN is a mechanism

to help rice scientists keep each other

informed of current research

findings.

The concise reports contained in

IRRN are meant to encourage rice

scientists and workers to communicate

with one another. In this way, readerscan obtain more detailed information on

the research reported.

guidelines, and research categories that

follow.If you have comments or suggestions,

please write the editor, IRRN, IRRI,

P.O. Box 933, Manila. Philippines. We

look forward to your continuing interest

in IRRN.

Criteria for IRRNresearch reports

Please examine the criteria,

has International, or pan-national,

has rice environment relevance advances rice knowledge uses appropriate research design

and data collection methodology

reports appropriate, adequate data applies appropriate analysis, using

appropriate statistical techniques reaches supportable conclusions

relevance

Guidelines forcontributorsThe International Rice ResearchNewsletteris a compilation of research

briefs on topics of interest to rice

scientists all over the world.

Contributions to IRRN should bereports of recent work and work-in-

progress that have broad interest and

application. Please observe these

guideline in preparing submissions:

The report should not exceed twopages of double-spaced typewritten

text. No more than two figures

(graphs, tables, or photos) may

accompany the text. Do not cite

references or include a

bibliography. Items that exceed the

specified length will be returned.

research objectives and project

design. The discussion should be

brief, and should relate the results

of the work to its objectives. Report appropriate statistical

analysis.

Provide genetic background fornew varieties or breeding lines.

Specify the environment (irrigated,rainfed lowland, upland, deep

water, tidal wetlands). If you must

use local terms to specify landforms

or cropping systems, explain or

define them in parentheses.

Specify the type of rice culture(e.g., transplanted, wet seeded, dry

seeded).

Specify seasons by characteristicweather (wet, dry, monsoon) and

by months. Do not use national or

local terms for seasons or, if used,define them.

When describing the rice plant andits cultivation, use standard,

internationally recognized

designators for plant parts and

growth stages, environments,

management practices, etc. Do notuse local terms.

Include a brief statement of

When reporting soil nutrientstudies, be sure to include standard

soil profile description,

classification, and relevant soil

properties.

diseases, insects, weeds, and cropplants; do not use common names

or local names alone.

Provide scientific names for

Survey data should be quantified(infection percentage, degree of

severity, sampling base, etc.).

When evaluating susceptibilityresistance, tolerance, etc., report the

to stress used to assess level or

incidence. Specify the

measurementsused.

actual quantification of damage due

Use international measurements.Do not use local units of measure.

Express yield data in metric tons

per hectare (t/ha) for field studies

and in grams per pot (g pot) or per

row (g row) for small-scale studies. Express all economic data in terms

of the US$. Do not use national

monetary units. Economic

Information should be presented at

the exchange rate $:local currency

at the time data were collected.

Use generic name, not tradename, for all chemicals.

When using acronyms orabbreviations, write the name in full

on first mention, following it with

the acronym or abbreviation in

parentheses. Thereafter, use the

abbreviation.

Define in a footnote or legend anynonstandard abbreviation or

symbols used in a table or figure.

Categories of researchreportedGERMPLASM IMPROVEMENT

genetic resources

genetics

breeding method

yield potentialgrain quality and nutritional value

disease resistance

insect resistance

drought tolerance

excess water tolerance

adverse temperature tolerance

adverse soils tolerance

integrated germplasm improvement

seed technology

research techniques

data management and computer

modeling

CROP AND RESOURCE

MANAGEMENT

soils and soil characterization

soil microbiology and biological Nfertilizer

physiology and plant nutrition

crop management

soil fertility and fertilizer managemendisease management

insect management

weed management

managing other pests

integrated pest management

water management

farm machineryenvironmental analysis

postharvest technology

farming systems

research methodology

data management and computer

modeling

SOCIOECONOMIC AND

ENVIRONMENTAL IMPACT

environment

production

livelihood

EDUCATION ANDCOMMUNICATION

training and technology transfer

communication research

Information storage and retrieval

research


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CONTENTS

GERMPLASM IMPROVEMENT

Genetics

4 Genetics of seedling elongation in rice

Breeding methods

production

4 Use of Purple Puttu rice variety as a pollen barrier in CMS line seed

4 Inbreeding depression of yield in rice hybrids

5 Micropropagation of cytosterile rice stocks

6 Tissue culture for Argentine rice (O. sativa L.) improvement

6 Morphoanatomy of rice embryoid development

Yield potential

7 Models for predicting rice flowering

Grain quality and nutritional value

8 Optical determination of rice grain chalkiness (Clk)

9 Protein content variation among rice varieties

Disease resistance

9 Multiple resistance to bacterial blight (BB) and four fungal diseases

10 Isolation of a plasmid from strains of Xanthomonas campestrispv. oryzae

11 Screening for blast (Bl) resistance in Hangzhou, China

11 Background resistance to bacterial blight (BB) hill and leaf infection

12 Neck blast (Bl) in newly released upland rice varieties in Brazil

13 Maintenance of virulence in Xanthomonas campestrispv. oryzae cultures

13 Leaf blast (Bl) outbreak at Faizabad, India

that cause bacterial blight (BB) in rice

Adverse temperature tolerance

14 Screening rice varieties for cold tolerance at seedling and reproductive

stages

Adverse soils tolerance

15 Effect of acidity on germination and growth of rice seeds

CROP AND RESOURCE MANAGEMENT

Soils and soil characterization

15 Influence of soil texture on rice crop performance

Soil microbiology and biological N fertilizer

16 Early, uniform stem nodulation in Sesbania rostrata after spray of

Rhizobium culture

Physiology and plant nutrition

different seasons

16 Influence of nitrogen and zinc application on nutrient uptake by rice in

Crop management

17 Environmental limitations to rice cultivation in the Punjab

Soil fertility and fertilizer management17 Effect of farmyard manure (FYM) supplemented with N, P, K on gra

18 Phosphorus requirements in a rice - wheat cropping system

18 Effect of two phosphorus sources with or without azolla incorporation

yield

rice yield in the Senegal River valley

Disease management

oryzae

Bangladesh

19 Four fungicides for control of grain infection caused by Helminthosporiu

20 Distribution and severity of rice seedling diseases in boro seedbeds

20 Managing rice sheath rot (ShR) disease in Kerala, India

21 Greenhouse trials of seed dress method for controlling sheath blight (Sh

22 Rice ragged stunt virus (RSV) in aquatic weed Monochoria vaginalis

Insect management

22 Influence of time of day and sweeping pattern on catches of gre

22 Effect of flooding on black bug Scotinophara coarctata (F.) e

23 Host range and overwintering of rice pink stem borer (PSB) in a hilly regi

24 Chemical control of rice stem borers (SB) in the Punjab

24 Monitoring susceptibility of rice pests to insecticides

leafhoppers (GLH)

parasitization

of India

Water management

requirement

25 Influence of planting method and irrigation practices on rice wa

Farm machinery

26 Manual rice transplanter use in Burma

Farming systems

26 Pigeonpea genotypes and rice yield in an intercropping system

27Rice

-

based cropping systems for optimum production under resouconstraints

ERRATA

ANNOUNCEMENTS

28 INSURF Planning Workshop

28 New IRRI publications


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were no anther sacs, and pollen grains

averaged 0.33 (see table).

At least 3 lines of Purple Puttu at 15

10-cm or closer spacing around CM

line seed production plots can effective

intercept pollen and anther sac dispers

between different cytosterile lines. An

added advantage is that Purple Puttus purple foliage distinguishes it from oth

varieties.

sunlight to 1000 h. The petri dishes were

placed 15 cm from the first stake at the

level of the glass slides and the muslin

cloth removed to allow anther sacs and

pollen grains to disperse by natural wind

velocity (7.2 km/ h to a height of 3 m).

Three such dispersals were made.

The slides were collected and thenumber of anther sacs and pollen grains

per square inch counted. Where there

were no plants of Purple Puttu in front

of the slide, anther sacs averaged 2.33

and pollen grains 12.66. After the first

row of Purple Puttu, anther sacs

averaged 1.66 and pollen grains 6.33 per

square inch; after the second row, there

Use of Purple Puttu rice

variety as a pollen barrier in

CMS line seed production

GERMPLASM IMPROVEMENT

Genetics

Genetics of seedling

elongation in rice

R. S. Tripathi, Agriculture Research Station,

Banswara, India

We studied the inheritance of seedling

elongation ability in an F2 population of

Pankaj/Nageribao under deepwater

conditions during the 1977 wet season at

the Central Rice Research Institute,

Cuttack. F2 30-day-old seedlings and

parental lines raised in shallow pans

were submerged in 80 cm water.

Seedling height was recorded after 10 d.

The frequency distributions of F2s and

parents are presented in the table.

Frequency distribution of parents and F2 for

seedling elongation in Pankaj/Nageribao.

Cuttack, India, 1977.

Frequency distribution

Plantheight

(cm)

Parents F2

Pankaj Nageribao

0-10 10-20 220-30 30-40

64

40-50 550-60 3 17

60-70 19 26

70-80 8 4680-90 2 70

90-100 8 99100-110 16 97110-120 3 61120-130 1 11130-140 2

Range (cm) 54.0-78.2 89.4-120.7

Average 67.2 110.4

In 446 F2 plants, 270 were 90-140 cm

tall, with elongation rates equal to tha

of the Nageribao parent; 60 plants

showed poor elongation (10-70 cm),

comparable to Pankaj; and 116 were

intermediate (70-90 cm), elongation

ability better than that of Pankaj but

not equal to that of Nageribao.

The data are consistent with two

dominant complementary genes for

elongation ability. Presence of both

genes (Sel 1 and Sel 2) gave elongation

ability like that of the Nageribao paren

Absence of either of the genes resulted

in segregants with intermediate

elongation ability; absence of both

resulted in plants like the Pankaj

parent.

Breeding methods

M. Rangaswamy, K. Natarajamoorthy, andS. R. Sree Rangasamy, School of Genetics,

Tamil Nadu Agricultural University,

Coimbatore 641003, Tamil Nadu, India

We assessed the distance of pollen

dispersal across lines of Purple Puttu

90 d after sowing, which coincides with

anthesis in the CMS lines now available

at the Coimbatore Paddy Breeding

Station. Purple Puttu has long duration

(150 d) and is highly photoperiod

sensitive (120 d to flowering in the wet

season, does not flower in the dry).

acetocarmine-glycerine were tied at

60 cm high to bamboo stakes between

six rows (15- 10-cm spacing) of

Purple Puttu. One gram fresh anthers

collected at 0800 h from a number of

varieties were bulked and kept in closed

muslin cloth bags in a petri dish under

Glass slides smeared with vaseline and

Rice pollen dispersal a with Purple Puttu as a

pollen barrier.

Purple Puttu Av for 3 applicationsrow number

Anthers/inch2 Pollen/inch2

0 row 2.33 12.66Row 1 1.66 6.33

Row 2 0.33Row 3 0.33Row 4

Row 5

a Wind velocity at 3 m = 7.2 km/h.

Inbreeding depression of yiel

in rice hybrids

M. Rangaswamy, H. Natarajamoorthy, an

S. R. Sree Rangasamy, School of Genetics


Coimbatore 641003, Tamil Nadu, India

Seven IRRI medium-duration hybrids

(130-140 d) were tested in 1986 wet

season as F1 (3 replications) and in 198

dry season as F2 (4 replications) for

inbreeding depression of grain yield.

Grain yields in the F2 ranged from

-28.59 to 3.62% compared to the F1(see table). The same F1 and F2 were

4 IRRN 13:2 (April 1988)


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compared with standard variety CO 43.

Inbreeding depression ranged from

-30.69 to -0.43%. Hybrids

IR54752A/ IR19392-2 11-1 and

IR54752A/ IR4422-480-2-3-3 had yield

stability in the F2, with low inbreeding

depression (-0.43 and -0.58%,

respectively). Their standard heteroses

were not significant.

Inbreeding depression (ID) of grain yield in hybrid rice.a Tamil Nadu, India, 1986-87.

F1 yield F2 yield

Hybrid, variety (t/ha) heterosis (t/ha) heterosis ID standard standard

1986 WS 1987 DS

F1 yield Standard F2 yield Standard over over ID overstandard

1986 WS (%) 1987 DS (%) (% ) (%) (%) (%)

IR46828A/IR13524-21-2-3-3-2-2 4.5 29.0 3.9 40.8 14.0 71.0 59.216.6

IR46830A/IR13292-5-3 4.5 29.0 4.5 32.1 1.4 71.0 67.9 4.3

IR54752A/IRl4753-120-3 7.0 +10.6 5.6 14.8 20.6110.6 85.2 23.0

IR54752A/IR19392-211-1 6.4 + 0.4 6.2 0.1 2.5 100.4 100.0 0.4

IR54752A/IR4422-480-2-3-3 4.2 34.2 4.4 33.8 + 3.6 65.8 66.2 0.6

IR54752A/IR20933-68-28-1-2 5.5 14.1 3.9 40.5 28.6 85.9 59.5 30.7

IR54752A/IR54 6.0 6.4 4.8 26.2 18.8 93.6 73.8 21.1

CO 43 (standard) 6.4 6.6 + 3.0 100.0 100.0

LSD 1.1 1.0

Micropropagation of

cytosterile rice stocks

D. S. Kumari, N. P. Sarma, and G. J. N.

Rao, Central Rice Research Institute

(CRRI), Cuttack 753006, India

We have propagated cytosterile rice

stocks by regenerating plants in callus

culture. The important consideration in

applying in vitro methods for

propagation is to retain the geneticintegrity of the original stock. There is a

risk of genetic variation in plants

regenerated after an intermediate callus

growth phase.

In vitro propagation of rice by

inducing axillary shoots or regeneration

from nodal buds ensures against the

possibility of genetic variation among

the regenerants.

of cytosterile stock V20A were

germinated on Murashige and Skoogs

(MS) medium with 50 g sucrose/liter but without auxins. Six-day-old excised

seedling shoots, without radicle and

endosperm, were implanted on fresh MS

medium supplemented with

benzyladenine (BA) at 0.5, 1, 1.5, and

2 mg/liter. The cultures were

maintained at 25 + 1 C with 16 h

photoperiod/d.

Dehusked and surface sterilized seeds

After 3 wk, multiple axillary shoots

formed from the basal region of the

implanted shoots. Axillary shoot

formation was highest with 2 mg

BA/liter (Table 1).

about 1 cm long, they were separated

When clumps of multiple shoots were

Table 1. Multiple shoot formation of the cyto -sterile stock V20A after 3 wk in culture. CRRI,

Cuttack, India.

Shoots Axillary shoots

(no.) after 3 wk

Mediuma implanted (no.) induced

MS + 0.5 mg BA 17 40MS + 1.0 mg BA 18 58MS + 1.5 mg BA 17 80MS + 2.0 mg BA 16 82

aMS basic medium with 50 g sucrose/liter.

and used as fresh implants on MS

medium containing different levels of

BA, kinetin (K), naphthalene acetic aci

(NAA), and indolebutyric acid (IBA)

(Table 2).

The number of shoots increased

slightly with the addition of K to the

medium. The best results were with BA

Adding NAA with BA did not promot

root growth; adding IBA with BA

induced weak roots. Root growth was

vigorous in MS medium supplementedwith NAA alone, but axillary shoots

were suppressed.

multiple axillary shoots in vitro is

feasible for the micropropagation of

valuable cytosterile stocks. Continuous

axillary shoot production is possible,

These results suggest that induction

Table 2. Effect of different growth regulators in multiple shoot and root formation. CRRI, CuttackIndia.

Growth regulators (mg/liter) Shoots Axillary shoots RootMediuma implanted

BA K NAA IBA

produced

(no.) (no.)

MS-1 2 26 100

MS-2 0.5 24 372 0.5

MS-4

14 432 1

MS-520 68

2 0.5 1 20MS-6

54 0.5 1 18 31 ++

1 12 211.5 12 12 +++

MS-3++

MS-7 2MS-8

+

aMS basic medium with 50 g sucrose/liter. b+ = weak, ++ = good, +++ = very good.

IRRN 13:2 (April 1988)

a ID =F2 - F1

F 100


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eliminating the risk of somaclonal

variation in successive subcultures. A

logical extension of the rate of

multiplication through successive

cultures should yield 1 5n axillary

shoots, where n is the number of

subcultures, with each cycle requiring

3-4 wk. Since rooting is essential to

establish the shoots in soil, an additional

cycle on MS medium supplementedwith root-inducing auxin NAA at

1.5 mg/liter may be necessary.

Table 1. Variation among the first progeny of Gualeyan P. A. regenerated plants (R2) and progen

of the original variety. Buenos Aires, Argentina, 1987.

Trait Gualeyan

Mean Range

Panicle length (cm) 17.66 22.08 12.09-25.6 **Grain with husk

Length (mm) 9.35 9.13 8.5 - 9.85 **

Grain without husk3.82 3.52 4.0 - 3.0 **

Length (mm) 7.11 7.78 6.3 - 1.85 **Width (mm) 3.11 2.89 2.5 - 3.15 **

R2 progenyF tes

Width (mm)

a ** = significant at 1% level.

Table 2. Variation among the first progeny of Yerua F. A. regenerated plants (R2) and progeny othe original variety. Buenos Aires, Argentina, 1987.

Tissue culture for Argentine-

rice (O. sativa L.)

improvementTrait

R2 progenyYerua F tes

Mean Range

M. A. Rapela and M. A. Marassi, Instituto

Fitotcnico de Santa Catalina, Facultad de

Agronomia, Universidad Nacional de la

Plata, C. C. 4, 1836 Llavallol, Buenos Aires,Argentina

Seeds of Argentine rice varieties Yerua

F.A. and Gualeyan P.A. were cultured

on Murashige and Skoogs (MS) basic

salts supplemented with 2 mg 2,4-D/liter

of medium in darkness at 28 C. Callus

formed 15 d after inoculation. Callus

induction was 100% in both varieties.

regeneration medium with the same

basic salts supplemented with 1 mg

BAP/liter. Plant regeneration was 30%

in Yerua, 50% in Gualeyan.

The plantlets were transferred to pots

containing sterile vermiculite and

watered with 1/4 MS salts. After 1 wk,

they were transplanted to the

greenhouse and grown to maturity.

Seeds were obtained from all the plants,

although fertility was not 100%.

Seeds from the regenerated plants and

seeds from the original varieties were

planted at 20- 20-cm spacing and

conventional cultivation procedures

followed. At maturity, sample plants

were collected to evaluate agronomic

traits; the rest were used for testing yield

characteristics and blast resistance.

regenerated from Gualeyan (R2 ) showed

higher tillering ability than the original

variety; 20% had a different husk color.

Calli were subcultured on a

The first progeny of plants

Panicle length (cm) 21.14Grain with husk

Length (mm) 10.34Width (mm) 3.54

Length (mm) 7.94Width (mm) 3.1

aSignificant at 1% (**) and 5% (*) levels.

Grain without husk

Panicle length and two grain

dimensionswith and without husk

also significantly differed (Table 1). The

first progeny of plants regenerated from

Yerua (R2 ) showed low plant height and

significant differences for panicle length,

grain width with husk, and grain length

Morphoanatomy of rice

embryoid development

F. J. Zapata and D. C. de Castro, Tissue

Culture Laboratory, Plant Breeding

Department, IRRI

Histological studies of cultured embryos

during the early stages of cell

proliferation provide information about

the initial sites and patterns of cell

division activity and subsequent

differentiation. Morphological

observations through the scanning

electron microscope (SEM) provide a

clear picture of the natural concave-

convex appearance of the various stages

of embryoid development.

22.30 12.3 - 3.0 **

9.67 11.0 - 6.53.74 3.25- 4.3 *

7.51 *3.04

ns

6.5 - 8.7

26.5 - 4.1 **

without husk (Table 2).

This study showed a definite trend

toward more somaclonal variation in

Gualeyan than in Yerua. The tissue

culture-derived plants may be useful as

sources of new germplasm.

Dehulled mature seeds of rice variety

Tetep were sterilized and inoculated in

Linsmaier and Skoogs (LS) medium,

each liter containing 1 mg 2,4-

dichlorophenoxyacetic acid (2,4-D)

gelled with 1% agar. Cultures were

maintained in darkness at 26-27 C.

The scutella were isolated from

embryos still embedded in the seed afte

1 wk in culture. Samples for histologica

and SEM analysis were taken 2, 4, 6, 8

10, and 12 d after seed inoculation;

subsequent samples from subcultures

were taken every 4 wk.

were transferred to Murashige and

Skoogs (MS) medium, each liter

containing 4 mg benzylaminopurine

For plant regeneration, 3-mo-old cal

6 IRRN 13:2 (April 1988)


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(BAP), 0.5 mg indole-3-acetic acid

(IAA), 0.5 mg naphthalene acetic acid

(NAA), 500 mg casein hydrolysate, and

3% sucrose gelled with 0.8% agar. The

calli were incubated at 26-27 C in

continuous 3000 lux light intensity.

Active cell division took place in the

scutellum, especially on the

subepidermal (sep) portion (see figure,

1-2). Calli formed on day 6 of culture.

Elongated structures were visible at the

periphery of the scutellum on day 10 (3).

Cells pushed out the epithelial layer,

giving the scutellum a wavy appearance.

Active cell division was visible on day

12. Smooth, compact, round and

whitish embryoids were obtained after 3

wk in culture (4).

Anatomical observations showed

embryogenic calli with densely packed

cells, prominent nucleus, and thin cell

walls (5). Nonembryogenic calli had

loosely packed cells, hardly visible

nuclei, and thick cell walls (5).

A SEM study (7) showed globular

and organized structures (e) proliferating

at the surface of the nonembryogenic

calli (ne). Embryoids containing the

scutellar portion, coleorhiza, and a

developing coleoptile (8) were exactly

Yield potential

Models for predicting rice

flowering

A. B. Dua and D. P. Garrity, Multiple

Cropping Department, IRRI

Models for predicting flowering in

cereals are often location specific. We

developed simple temperature-

dependent regression models that can

estimate flowering in lowland irrigatedrice. Data from 43 rice experiments

conducted at 23 irrigated sites in Asia,

Africa, and Latin America that ranged

from 09'S latitude (Ahero, Kenya) to

3716'N latitude (Suweon, Korea) were

evaluated for relationships between

mean temperature, photoperiod, and

flowering date.

cultivars IR9729-67-3 (very early), IR36

Three maturity groups, represented by

like the zygotic embryo, but sometimes

did not have synchronized developmen

Embryogenic calli transferred to

regeneration medium produced prolific

shoots and plantlets from embryoids

after 3 wk in culture.

and BG35-2 (early), and Taichung SenYu 285 (medium), were tested for best

fit to generalized thermal or

photoperiod models. Thermal units (Tu

for each 24-h interval had been recorded

in agrometeorological stations in the

vicinity of the experiments. Daily

thermal units were calculated as the

mean of the daily maximum (T max) and

minimum (Tmin) temperatures and

summed for the period from seeding to

flowering (SF).

Accumulated thermal units for the

period transplanting to flowering (TF)also were computed. Photoperiod (p) at

panicle initiation was estimated, using

meteorological algorithms. Reciprocals

of the durations of SF and TF were

calculated as the average rate of

progress toward flowering. Average rat

of progress toward flowering showed a

curvilinear trend with mean temperature

(see figure). This relationship was

derived from data across the four

Rice embryoid development: 1 = longitudinalsection of a seed embryo showing the coleorhiza (cr),

coleoptile (cl), scutellum (sc), and subepidermallayer (sep); 2 = callus formation at the subepidermallayer of the sc; 3 = thallus structure proliferatingfrom the surface of the sc; 4 = 3-mo-old smooth,compact, round, and whitish embryoids; 5 = anembryogenic callus; 6 = a nonembryogenic callus; 7= scanning electron micrograph of embryogeniccalli (e) proliferating at the surface of nonembryo-genic (ne) calli; 8 = scanning electron micrograph ofan embryoid with sc, cr, and a developing cl. IRRI,1987. Rate of development from seeding to flowering of IR36 (1/f) vs mean temperature.

IRRN 13:2 (April 1988) 7


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Optical determination of rice

grain chalkiness (Clk)

Jin Qingsheng and Qiu Baiqin, Crop

Institute, Zhejiang Academy of Agricultural

Sciences (ZAAS), Hangzhou, China

We used a digital grain translucency

meter (DWY-1A model, manufactured

by ZAAS) to measure grain

translucency of 17 IR varieties grown in

early season 1986. Samples of whole

milled rice were tested, with three

replications.

Mean translucency and corresponding

Clk scale are shown in the table. Asignificant negative correlation was

found between grain translucency and

Clk (see figure). For rice breeding work

or in grading for market value, this

meter can be used instead of visual

rating to measure the degree of Clk.

Optical determination of Clk is not

possible with waxy rice because the

opaque endosperm also reduces grain

translucency.

Photo-thermal models for predicting flowering in IR36 across locations. Screened data set of 43trials from a global rice-weather study. 1987.

ModelRegression coefficientsa

a b cR2 CV

d

Seeding to flowering1. 1/f = a + b*Tmean 0.00165ns 0.00471** 0.39 13.0

2. 1/f = a + b*TU 0.02171** 0.0000425** 0.75 8.2

3. 1/f = a + b *TU+c*p+d*p2 0.0733** 0.00000385** 0.0148** 0.000579** 0.79 6.8

(0.00233) (0.00009)

(0.000994) (3.93 E-07)

(0.0236) (4.57 10 E-10) (0.00366) (0.000141)Transplanting to flowering

1. 1/f = a + b*Tmean 0.00334ns +0.000695** 0.37 12.7(0.00359) (0.00138)

2. 1/f = a + b*TU 0.0302** 8.64 E-06** 0.81 7.0

3. 1/f = a + b*TU+c*p+d*p2 0.0707* 8.15 E-06** +0.0156** 0.000607** 0.78 6.3

(0.00117) (6.44 E-07)

(0.0307) (8.28 E-07) (0.00476) (0.00184)

level. 1/f = progress toward flowering, i.e., the reciprocal of the time from seeding to flowering (SF)

a*, ** = 0.05 and 0.01 significance levels, respectively, ns = estimated values not significant at the 5%

or transplanting to flowering (TF). p = photoperiod. TU = accumulated thermal units. Tmean =mean temperature (C) from seeding to flowering.

latitude groups. The optimum

temperature for maximum developmen

rate in IR36 was 26.8 C.

A simple model using accumulated

thermal units accurately estimated the

rate of progress toward flowering (see

table). Best fit models included a

quadratic photoperiod term (p) that

accounted for daylength effects. Model

for genotypes maturing earlier (IR9729

67-3 and BG35-2) and later (Taichung

Sen Yu 285) than IR36 were very simil

in performance.

developing simulation models of rice

growth and development that rely on a

accurate prediction of phenological

events under a wide range of

temperatures and daylengths.

These data may be useful in

Grain quality and nutritional value

Grain translucency and Clk rating in milled rice

of 17 IR varieties, evaluated by digital trans-lucency meter. Hangzhou, China, 1986.

Variety

IR22 90.7 1.4

IR24 81.0 2.8IR28 84.0 2.6IR30 70.0 6.5IR34 88.0 3.3

IR36 86.3 3.2

IR38 80.7 5.2IR43 79.7 3.9IR44 84.3 3.6IR45 86.7 5.0IR46 82.3 1.0IR52 78.7 1.4IR54 89.0 1.5

IR56 85.0 1.0IR60 85.7 1.0IR62 90.7 1.0

IR64 77.3

Translucency

(%)Clk

4.1Relationship between Clk scale and translucency measured in milled rice of 17 IR varieties, 1986.

8 IRRN 13:2 (April 1988)


9/28

Protein content variation

among rice varieties

M. Jayapragasam, A. Manickam, N. M.

Ahamad, and B. Thayumanavan,

Biochemistry Department, Tamil Nadu

Agricultural University, Coimbatore 641003,

India

We analyzed the grain of 294 ricegenotypes raised in the same field under

similar cultural operations for protein

content, using conventional micro-

Kjeldahl method. Grain samples were

dehusked by hand- pounding. Brown rice

protein content was expressed as dry

weight % after multiplying by 5.95.

Total protein varied from 4.94% in

Ratna and Sona to 12.86% in ADT21.

ASD10, T3 (Tainan), and T8 had

protein contents higher than 12%. Thirty

samples contained more than 10%

protein; 112 samples, 8-10%; 137

samples, 6-8%; and 15 samples, less than

6%. Ten of 40 ADT varieties had more

than 10% protein. TKM and ADT

Disease resistance

Multiple resistance to

bacterial blight (BB) and four

fungal diseases

R. N. Singh and A. T. Khan, N. D.

University of Agriculture and Technology,

P. O. Dabha Semar, District Faizabad

224133, U. P. India

We tested 233 rice varieties and lines in

the 1986 National Screening Nursery

and Multiple Resistance Screening Trial

for resistance to BB, sheath rot (ShR),

brown spot (BS), false smut (FS), and

narrow brown leaf spot (NBLS) diseases

during 1986-87 wet season. Each test

entry was planted in 2-m-long rows at20- 15-cm spacing.

Plants in half of the rows were clip-

inoculated with a suspension of a local

isolate of Xanthomonas campestrispv.

oryzae (Ishiyama) Dye at maximum

tillering. BB was rated at 15 and 30 d

after inoculation. Reactions to high

natural BS, NBLS, ShR, and FS disease

Mean and dispersal coefficient of variation of protein content of grain of some rice varieties. Tam

Nadu, India.

Soluble protein Total protein

Samples Mean CV (%) Samples Mean CV (%Varieties

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

ADT varieties 39 0.5 1 63.3 40 9.08 17.9

ASD varieties 18 0.97 38.7 18 8.87 18.7

CO varieties 18 0.68 36.8 28 8.1 1 12.8

CO32 mutants 4 0.5 6 24.3 4 7.32 14.6

CO33 mutants 10 0.81 32.3 10 8.50 18.8

IR varieties 6 0.48 37.3 8 7.18 12.1

Ponni/IR8 (F4) 39 8.45 5.5

Tainan varieties 50 1.05 30.0 50 8.74 16.1

TKM varieties 8 0.89 39.7 8 9.10 17.4

TKM6 mutants 11 1.00 24.0 11 7.64 20.8

Other varieties 77 0.57 40.4 78 7.62 17.3

All genotypes 24 1 0.74 48.2 294 8.26 17.2

varieties had the highest average protein

content, 9.1%.

Hot-water soluble protein estimated

colorimetrically by Lowry's method

showed greater variation than total

protein (see table). The Tainan types

had the highest average soluble protein

content (1.05%). Total protein and

soluble protein contents of the grain

were not significantly correlated. Prot

of 62 varieties soluble in 0.1 M NaOH

and determined by Lowrys method w

very highly significantly correlated wit

micro-Kjeldahl protein (r = 0.93**). T

coefficient of variation for data from

Lowry's method (18.11%) was slightly

lower than that for the micro-Kjeldah

method (19.41%).

Resistance of varieties and lines to BB, ShR, BS, FS, and NBLS.a

Uttar Pradesh, India, 1986-87 w

season.

Varieties (%)

Disease-free Resistant Moderately susceptible SusceptiDisease

BB 0 42.0 47.2 10.7ShR 0.4 45.4 48.5 5.BS 0 23.2 73.0 3.FS 26.2 43.0 24.0 6.

NBLS 65.7 3.4 13.7 17.

aData based on 233 varieties except for FS and NBLS, where observations were recorded on 221 231 lines. respectively.

pressure were taken on plants in the

other half of the rows.

No variety or line escaped BB and BS

(see table). Only one remained free of

ShR; 26.2% escaped FS. Because NBLS

appeared late in the season, a majority

of the varieties (65.67%) escaped thedisease; however, the highest number of

entries showed susceptibility. More

varieties showed resistance to ShR

(45.45%) and moderate susceptibility to

BS (72.96%); fewer were resistant

(3.43%) and moderately susceptible

(13.74%) to NBLS.

IET8958, IET9313, IET9843, and

IR50 showed multiple resistance to BB

ShR, BS, and FS; IET8340 showed

resistance to BB, ShR, FS, and NBLS

Entries with multiple resistance to thre

diseases included IET7511, IET7720,

IET7978, RP16691-2897-5526, and

IR29652-65-2-3 to ShR, BS, and FS;IET8022, IET8023, IET9965, and

IR32429-45-3-2-6 to BB, ShR, and BS

IET8364, IET8653, IET8611, and

IET9799 to BB, BS, and FS; and

IET8588 to ShR, FS, and NBLS. A

large number of entries possess

resistance to two diseases, many others

are resistant to one disease.



10/28

Isolation of a plasmid from

strains ofXanthomonas

campestris pv. oryzae that

cause bacterial blight (BB) in

rice

Vijai Pal, Plant Pathology Department,

Haryana Agricultural University, Hisar

125004, India; and L. Gardan and M.Charles, Institut National de la Recherche

Agronomique (INRA), Station de

Pathologie Vegetale et Phytobacteriologie,

Beacouze 49000 Angers, France

One or more indigenous plasmids in

several phytopathogenic spp. of

Agrobacterium, Corynebacterium,

Erwinia, Pseudomonas, and

Xanthomonas have been demonstrated

to carry the determinants of bacterial

pathogenicity. We investigated the

presence of plasmids in various strainsof Xanthomonas campestrispv. oryzae

and evaluated their physical and

pathological properties.

national collection of phytopathogenic

bacteria, INRA, Angers, and strains

XCOH-9 and XCOH-40 from Haryana

Agricultural University, Hisar, India.

Strain L5-30 of Rhizobium meliloti with

plasmid pRMe, molecular weight (MW)

89 106 dalton; strain M 175.4 of

Enterobacter cloacae with 2 plasmids,

MW 155 106 and 71 106 dalton;strain V-517 ofEscherichia coli with

Strains 1948 and 1981 came from the

1. Agarose gel electrophoresis of plasmid DNA of

known MW along with the 4 strains of X. campestris

pv. oryzae. Track 1, lysate from strain 1948; 2, lysate

from strain XCOH-9; 3, lysate from Rhizobium

meliloti strain L5-30 carrying plasmid pRMe (MW

89 106 dalton); 4, strain 1981; 5, lysate from E. coli

strain V-517 carrying plasmid pVA517A(MW 35.8

106 dalton); 6, lysate from E. cloacae strain M

175.4 carrying plasmids pRE-175 upper band (MW

155.3 106 dalton) and lower band (MW 71.5

106 ); 7, lysate from XCOH-40.

10 IRRN 13:2 (April 1988)

2. Electron microphotograph of plasmid DNA isolated from Xanthomonas campestrispv. oryzae.

plasmid pVA517A, MW 35.8 106 physical measurement. The MW of the

dalton; and several other plasmids plasmid of X. c.pv. oryzae was about

ranging in size from 1.36 106 dalton to 20.3 106 to 21 106 dalton as

4.8 106 dalton were used as reference determined by electron microscopy and

strains for measuring the MW of the agarose gel electrophoresis (Fig. 2).

plasmid species of X. c.pv. oryzae. Taichung Native 1 rice seedlings

All the strains were grown overnight grown in plastic pots (12 cm diam) wer

in 5 ml broth in a shaker at 28 C. The individually inoculated by tip clipping a

cells were harvested by centrifuging at 90 d after sowing with all the test strain

8000 g 10 min and thoroughly of X. c.pv. oryzae. Each strain was

resuspended in 2 ml of E- buffer (40 mM reisolated from diseased seedlings (afte

Tris-acetate, pH 9, 2 mM sodium five pathological tests in serial) and the

EDTA). The suspension was lysed by plasmids again analyzed by geladding 4 ml of lysis solution (3% sodium electrophoresis.

dodecyl sulfate in 50 mM Tris-OH All four reisolated strains showed the

buffer, pH 12.6) at 90 C for 20 min. presence of a plasmid with the same

The lysate was emulsified with 6 ml of MW, indicating the stability of this

phenol-chloroform mixture (1:1 by plasmid in the different strains. The

volume) and centrifuged for 10 min at presence of a plasmid in X. c.pv. oryza

8000 g. strains may provide an opportunity for

recovered and used for agarose gel indigenous plasmids in BB

electrophoresis (0.7% agarose in a development.

vertical Lucite slab gel apparatus). The

gels were stained in ethidium bromide

solution (0.4 g/ml) and visualized overan UV-transilluminator (Fig. 1). The International Rice Research

estimated by electron microscopy and

by plotting the relative mobility of

against the logarithm of plasmid MW of 933, Manila, Philippines.reference standards determined

previously by electron microscopic and

The upper aqueous phase was understanding the involvement of

The MW of the plasmid was Newsletter is mailed free to individualsand institutions engaged in rice researchand training. For further information,write IRRI, Communication and

plasmid DNA bands in the agarose gel Publications Dept., Division R, P.O. Box


11/28

Varieties or lines resistant to B1 at CNRRI,

Fuyang Experiment Station, Hangzhou, China,

1987.

Variety or line

BG380-2C712035C721313C731110HPU5010-PLP21-2-1BIR13524-21-2-3-3-2-2IR19349-135-2-3-2-1IR19670-57-1-1-3IR31868-64-2-3-3-3IR32429-122-3-1-2IR35353-94-2-1-3IR35410-16-3-2-2-2-2IR37865-29-3-1-3IR39379-20-1-2-1-1

IR7732-RGA-B-A96-1SR9713-31-2-3

Suakoko 8 (2526)

Tetep32-Xuan-5-BEr Jiu Feng (resistant

check)Guang Lu Ai No. 4 9 5 9

(susceptible check)

Score a

Seedling Leaf Neck

5 0 14 1 03 1 03 1 04 0 04 0 03 0 03 1 34 0 04 0 03 0 03 3 04 0 02 0 0

4 2 00 0 03 1 33 3 0

4 0 35 2 5

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

Screening for blast (Bl)

resistance in Hangzou,

China

Shen Ying, Yuan Xiao-ping, and Huang Shi-

wen, China National Rice Research Institute

(CNRRI); and Lu Fu-ying, Zhejiang

Agricultural University, Hangzhou,

Zhejiang, China

Rice Bl is one of the most widely

distributed diseases in China. Heavy

infections on panicles are often

detrimental to rice yields. We screened

113 entries under natural disease

pressure at the CNRRI Fuyang

Experiment Station during 1987.

One-month-old seedlings were

transplanted in 2 rows at 20- 20-cm

spacing. One row each of susceptible

checks Yuan Feng Zao and Guang Lu

Ai No. 4 and resistant check Er JiuFeng were transplanted between each

entry and on all sides. Soil was sandy

loam with medium fertility. Fertilizer

was applied at 75-37.5-25 kg NPK/ ha.

A local predominant strain of the Bl

pathogen was collected and isolated

from naturally infected leaves and a

spore suspension sprayed at 2 wk after resistant to Bl (see table). C721313,

transplanting to help initiate infection. C731110, HPU5010-PLP21-2-1B,

The spore suspension concentration was IR13524-21-2-3-3-2-2, IR31868-64-2-3-3

adjusted to 5 10 5/ml. Seedling, leaf, 3, IR32429-122-3-1-2, IR39379-20-1-2-1

and neck Bl were scored at four leaf 1, IR7732-RGA-B-A96-1 have good

ages, maximum tillering, and maturity. grain quality and high yield potential.Of 113 entries screened, 19 were

Background resistance to

bacterial blight (BB) hill and

leaf infection

T. W. Mew and C. M. Vera Cruz, IRRI

In the Philippines, rices with the Xa-4

gene for resistance to race 1 of

Xanthomonas campestrispv. oryzae are

affected by the virulence of race 2, the

dominant bacterial pathogen

population. Although more than 80% ofthe rice area is planted to varieties with

such resistance, BB occurs endemically

in specific localities. The level of

infection varies, even though the same

resistance gene Xa-4 confers resistance.

We assessed reactions of commonly

planted varieties to both virulent and

avirulent races to determine if other

components influence their resistance.

Races 1 and 2 and IR20, IR22, IR26,

IR36, IR42, IR48, IR50, IR54, IR56,

IR58, IR60, and IR62 (all known to

carry Xa-4) were used.

Plants raised in the screenhouse wer

inoculated at 21 d after sowing with

isolate PXO 61 of race 1 (avirulent) an

PXO 86 of race 2 (virulent). IR24,

which carries no gene for BB resistanc

was the susceptible check. Hill and

leaf/ hill infection was measured at thr

growth stages.

The relative resistance index (RI) us

Resistance or susceptibility of IR cultivars carrying Xa-4 gene for BB resistance to 2 races ofXathomonas campestris pv. oryzae at 3 growth stages. a IRRI, 1986 dry season.

Early tillering Maximum tillering

Variety Hill Leaf Hill Leaf Hill

Booting stage

Leaf

infection infection infection infection infection infecti

(%) (%) (%) (%) (%) (%)

PXO 61IR24 b 91.6 29.6 91.6 23.8 52.0 14.8IR56 91.6 28.4 87.4 17.0 52.0IR50

9.645.8 11.4 50.0 5.4 8.2 0.8

IR60 43.8 11.8 33.4 3.2 4.2IR42 37.6

0.211.2 6.2 0.2

IR22 33.4 7.2 12.4IR58 33.4

1.8 6.8 18.8 1.8 4.2 0.6

IR62 27.0IR36

7.4 29.2 3.8 10.427.0

2.29.6 20.8 1.6

IR200

25.0 7.6 12.4 1.6 14.6IR54

1.820.8

IR265.6 35.4 2.2 2.2 0

18.8 3.8 6.2 0.6 2.0 0.4

IR24 b 73.0 23.8 87.6 25.6 75.0 24.0IR56 95.8 30.8 91.6 20.0

IR50 98.0

73.0 13.4

31.8 100IR60

21.491.6

70.829.2

16.8

IR4277.0 14.4 58.4

70.810.0

23.0 60.4 12.0 IR22 75.0 25.0 62.4 12.4IR58 58.4 16.8 81.2 20.8IR62

70.8 20.868.8 17.8 79.0

IR3619.4

66.6 15.6 60.4 9.270.8

85.418.2

IR2016.4

43.8IR54

22.4 58.4 56.2 12.039.6

13.211.8 67.6

IR2624.0

75.060.8

26.2 64.6 19.8 60.4 18.621.8

a Mean of 2 replications. b Susceptible check.

PXO 86

IRRN 13:2 (April 1988) 1


12/28

to measure resistance is based on a

comparison of the amount of disease on

IR24. The effect ofXa-4 on the

individual race was estimated by the

formula

DL of IR24 - DL of IR cultivar

100RI =

DL = disease level (% hill infection, %

leaf infection, % lesion area)A zero RI means that resistance equals

that of IR24.

A wide range of hill and leaf infection

with the two races was observed (see

table). Infection with the virulent race

was higher than with the avirulent race

at both maximum tillering and booting.

Based on hill infection, the RI of

varieties infected with the avirulent race

increased as the plants matured (see

figure). The RI of varieties infected with

the virulent race also increased.The data seem to suggest that these

varieties possess a distinct background

Relative resistance index, based on hill infection, of selected IR varieties to races 1 (PXO61) and 2 (PXO86) of Xanthomonas campestrispv. oryzae as compared to that of IR24, the susceptible variety, at 3 growth stages,

IRRI, 1986 dry season, + = more resistant than IR24, - = more susceptible than IR24.

12 IRRN 13:2 (April 1988)

resistance that increased as the plant

matured. Using hill and leaf infection as

parameters, such background resistanc

may not be shown at early tillering.

Because difference in disease level

induced by PXO 61 and PXO 86 is

related to the effect ofXa-4, the DL of

test variety not matched by PXO 86 is a

measure of background resistance.

Although the measurement is indirect,differences at different growth stages

were clear. Perhaps this background

resistance slows down epidemics in

farmers fields in the Philippines, even

though the race 2 population is

increasing with an increase in hectarage

planted to varieties with similar genetic

backgrounds. Background resistance

could be an attribute of the durability o

resistance of IR cultivars carrying the

Xa-4 gene.

For instructions on preparation of brief

reports of rice research to submit for

publication in IRRN, see the inside fron

cover of this issue.

Neck blast (BI) in newly

released upland rice varieties

in Brazil

E. P. Guimaraes, O. P. de Morais, and M.

H. G. L. Chatel, National Research Center for Rice and Beans (EMBRAPA/CNPAF)

Caixa Postal 179, 74000 Goiania, GO, Braz

Upland rice varieties Rio Paranaiba

(IAC47/63-83), Araguaia

(IAC47/TOS2578/74-2-3-B2), and

Cabau (mutant of IRAT79) were

released to the Cerrado Region in

Brazil. They were evaluated in

consecutive years 1984-85, 1985-86, and

1986-87 in Goiania with local check

IAC47.

Neck Bl increased and grain yielddecreased for all varieties tested (see

table). The increase in all cultivars was

independent of the degree of resistance.

Disease and yield were significantly

different between IAC47 and the

improved varieties. The newly released

upland varieties had higher neck Bl

resistance, and yielded more.


13/28

Neck Bl incidencea and grain yield of newly released upland rice cultivars and local check IAC47.b Goiania, GO, Brazil, 1986-87.

IAC47 Rio Paranaiba Araguaia Cabacu Year mean

Growingseasonc Neck B1 Grain Neck B1 Grain Neck B1 Grain Neck B1 Grain Neck B1

yield yield yield yield y

(t/ha) (t/ha) (t/ha) (t/ha) (

1984-85 (6) 3.2 2.6 1.3 3.4 1.l 2.8 1.2 2.9 1.7 c 2

1985-86 (4) 3.9 1.3 3.0 2.0 2.7 2.1 2.9 1.9 3.9 b

1986-87 (4) 8.7 0.8 5.6 1.6 5.1 1.6 5.4 1.3 6.2 a 1

1

Cultivar mean 6.2 a 1.6 b 3.2 b 2.4 a 2.9 b 2.2 a 3.1 b 2.1 a

aDisease evaluation scale 1 to 9, Standard evaluation system for rice. bMeans were compared using Tukey's test at 5% level of significance. abc show ferences among year means; ABC show differences among cultivar means. c Figures in parentheses = number of trials.

Maintenance of virulence in

Xanthomonas campestris pv.

oryzae cultures

J. C. Durgapal, Division of Mycology and

Plant Pathology, Indian Agricultural

Research Institute, New Delhi 110012, India

The loss of virulence in phytopathogenic

bacterial cultures maintained on culture

medium is a common phenomenon. In

the absence of lyophilization facilities,

cultures of Xanthomonas campestrispv.

oryzae, the pathogen of bacterial blight,

not only decline in virulence but

occasionally even lose viability within a

year of maintenance on a culture

medium under refrigeration. We

evaluated the suitability of sterile

distilled water columns, top layeredwith liquid paraffin, for long-term

maintenance of the bacterium.

in round- bottomed, screw-capped test

tube (about 7.5 cm high, 1.5 cm outer

diameter) was provided with a 0.5-cm-

thick top layer of medical grade liquid

paraffin and autoclaved at 15 lb pressure

for 30 min. Bacterial growth from

nutrient agar slant 48 h old was

transferred aseptically to the column

and stored at 10 C.

In Oct 1980, cultures of three virulentgradeshighly, moderately, and weakly

virulentwere preserved by this

technique. An identical set was

maintained under refrigeration on

culture medium (modified Wakimotos

medium: 5 g peptone, 20 g sucrose, 0.5 g

Ca(NO3)2. 4 H2O, 0.5 g FeSO4

.7H2O,

2 g Na2HPO4 2H2 O; 20 g agar, 1000 ml

A distilled water column 2.5 cm high

distilled water, pH adjusted to 6.8), with

subculturing at 6-mo intervals.

The viability of the preserved cultures

was tested. With a wire-loop, a minute

amount of the bacterial mass available

as sediment at the bottom of the water

columns was transferred to medium

slants and incubated at 27 C. An

aqueous suspension of 48-h-old fresh

culture at about 109 cells/ml served as

inoculum.

About 20 fully developed young

leaves of TN1 rice plants at the

maximum tillering stage were inoculated

by leaf tip cutting. Virulence was

determined by average lesion length

measured 15 d after inoculation. The

cultures were graded weakly (0.1-

5.0 cm), moderately (5.1-12.0 cm), or

highly (>12.0 cm) virulent.Cultures preserved in the water

column and those maintained on culture

medium were tested for viability and

virulence at 1, 3, and 6 yr.

Each culture in a water column was

still viable in the last test in 1986, with

no appreciable decline in initial

virulence. In the cultures maintained on

culture medium, the moderately and

weakly virulent types survived to the last

test, but 2 of the 3 highly virulent

cultures lost viability within 1 yr.

The pathogenicity test furtherrevealed a gradual loss of virulence in

highly and moderately virulent cultures.

In the last test, three cultures (one highly

virulent and two moderately virulent)

became avirulent; the rest reacted as

weakly virulent.

Sterile distilled water columns top

layered with liquid paraffin served as a

remarkably suitable and effective

medium for long-term maintenance of

X. c.pv. oryzae cultures. The preserve

cultures not only remained viable, but

retained their original pathological

characteristics for several years. This

inexpensive and easily manageable

device could be a reliable base for

maintaining the bacterium in its virule

form in laboratories lacking

lyophilization facilities.

Leaf blast (BI) outbreak at

Faizabad, India

P. Mukerjee, S. P. S. Rathi, and D. M.

Maurya, Crop Research Station, Narendra

Deva University of Agriculture andTechnology, Masodha, P.O. Dabha Semar

Faizabad, India

Severe leaf Bl caused by Pyricularia

oryzae had not been observed around

Faizabad, specifically Masodha and

Sohawal block, for 10 yr. During the

1986 wet season (Jun-Dec) at C. R. S.

Masodha, it appeared only on N22 at

the milk stage, and only on the upper

and flag leaves; the neck was not

affected. During the 1987 wet season,

N22 and Bagri showed severe infectioin early Aug at tillering; plants were

completely killed by the second week

Aug.

Under upland rainfed conditions in

trials at C. R. S. Masodha, where

disease pressure was highest, some new

developed lines showed high resistance

to leaf Bl; indigenous varieties were



14/28

highly susceptible. Satha D, Akashi, Lalmati-A, Lurkan, Miriti, Kachni,

Bagri, and N22 were most susceptible. Rani Kajal, Satha-F, and Sarya had

Bagri Black, Bagri White, Bhadaila kala, moderate infection.

Budhi, Gorakhpur local, Kudia, In farmers' fields, severe leaf B1

Adverse temperature tolerance

Screening rice varieties for

reproductive stages showed low tolerance for cold at the

yellowing and plant height were scored

at 25, 45, and 55 d after sowing (DAS).cold tolerance at seedling and Two new lines ES1-2-3 and ES1-1-1

S. K. Sinha, S. Biswas, and S. K. B. Roy,

Rice Research Station, Chinsurah 712102,

India

seedling stage and flowered earlier than

the check variety IR50. Both lines had

similar seedling height and leaf number

at 55 DAS; number of tillers/plant at

Cold tolerance at the seedling stage as

well as at the reproductive stage is

essential for early dry season rice in

West Bengal. We screened a number of

newly developed lines and three hillvarieties in 1984-85 to identify genotypes

possessing both characters.

Seeds were sown 21 Nov 1984. Leaf

harvest was lower than that of IR50 (see

table).

Two hill rice varieties introduced

from Bhutan, MAAP and KAAP,

showed high seedling tolerance for cold,and flowered earliest. But number of

tillers/ plant was very low. Khonorullo,

another hill rice, showed cold

Characters related to cold tolerance at different growth stages. a West Bengal, India, 1984-85.

was observed on popular indigenous

varieties Lalmati, Mutmuri, N22,

Mutmuriya, and Bagri.

susceptibility at all growth stages, with

delayed heading. CB-1 (Chinsurah

Boro-1) exhibited high seedlingtolerance for cold but flowered late.

Awned and red grains also restrict CB-1

use.

Varieties that flowered around mid-

Mar in West Bengal usually experience

temperatures of 22-25 C during panicl

development and produce a higher

percentage of filled spikelets/ panicle.

Using the Bhutanese varieties that

flower between 17-19 Mar in the

hybridization program may provide

plants that flower early, with cold

tolerance at both seedling andreproductive stages, suitable for dry

season (boro) rice in West Bengal.

Leaf yellowinga Seedling ht (cm)Genotype

Leaf no. a

SourceTillers

Days

25 DAS 45 DAS 55 DAS 25 DAS 45 DAS 55 DAS 25 DAS 45 DAS 55 DAS(no./plant)

heading

New lines

IR9262-5-2-2-2 IRRI 5 7 7 6 8 10 3 3 4 10 125

IR15579-135-3 3 5 5 7 9 12 3 4 5 9

IR7167-33

-2-4-2

-3 IRRI

125

5 7 7 6 8 9 35 7 7 6 9 12

3 5 9 131IR13155-60-3-1 IRRI 3 3 5 10 127

IR5716-18-1 IRRI 5 5 5 7 8 10 3 4 5 9 127

IR8866-30-3-1-4-2 IRRI 5 7 7 6 8 10 3 4 4 9 131ES1-2-3 India 3 5 5 5 9 10 3 4 4 6 117ESl-1-1 India 5 5 5 5 9 10 3 4

IR50

4

IRRI 5 7 9 6 8 9 3 4 5 10 129

7 118

Hill rice

MAAP Bhutan 1 1 1 10 12 15 3 4KAAP Bhutan 1 5 7 8 12 3 4

516 5

IRRI

3 1154 113

Khonorullo Bhutan 5 7 7 6 9 11 3 4 5 7 131

Local checkCB-1 India 1 1 1 12 15 20 3 4 5 13 139

Average diurnal temp (C) 20 19 18

a By the Standard evaluation system for rice scale.

The International Rice Research Newsletter invites contributions of concise summaries of significant current rice research for

publication. Contributions should be limited to no more than 2 pages typed double-spaced, accompanied by no more than 2 figures,

tables, or photographs. Contributions are reviewed by appropriate IRRI scientists and those accepted are subject to editing and

abridgment to meet space limitations. Authors are identified by name and research organization. See inside front cover for more

information about submissions.

14 IRRN 13:2 (April 1988)

to


15/28

measured (see table).

2.0. All seeds germinated at pH 3.0 an

above except for CSR4 and IR28222-

Adverse soils tolerance No seeds germinated at pH 1.0 and

Effect of acidity on 3.0, 4.0, 5.0, 6.0, and 7.0 by adding 2-2-2-2. No variety produced root that

germination and growth of

rice seeds

A. K. Bandyopadhyay, Central Soil Salinity

Research Institute, Regional Research

Station Canning, PO:Canning Town, Dist:

24-Pgs, West Bengal, India

Germination is an acute problem in

coastal acid saline soils that remain

highly acidic during the premonsoon dry

hydrochloric acid. Ten seeds were kept could be measured at pH 3.0. BG35-2

in each solution in petri dishes, with BW100, B2149B-PN-26-1-1, and RD

three replications. Water volume was appear highly promising for coastal ac

maintained by adding solution. After 4 saline soils where germination is a

d, the germinated seeds were counted problem.

and seedling height and root length

Effect of acidity (pH 3, 4, 5, 6, 7) on growth of rice seeds. West Bengal, India.

Seedling ht (cm) Root length (cm)

3 4 5 6 7 3 4 5 6 7Variety

period. We screened 118 IRRI

germplasms in acid saline soils havingBWl00 4.5 6.3 6.7 6.0 5.4

pH 3.5. Nine varieties were selected.5.5 7.0 8.0 8.

A laboratory experiment was IR28222-9-2-2-2-2 1.2 7.3 1.7 6.2 6.3 r 2.5 3.5 5.0 5.

conducted to evaluate comparative3.0 5.5 5.6 5.2 4.3 a 2.0 5.0 3.5 4.1.2 6.0 5.3 4.5 4.5 c 5.5 8.0 6.0 7.

tolerance of the selected varieties for Mahsuri 1.2 5.5 5.2 4.7 5.2 e 5.0 6.5 3.0 3.

BG35-2 3.5 6.3 6.0 6.0 5.7 5.5 5.5 3.5 3.

B2149B-PN-26-1-1 3.4 6.7 7.7 7.0 5.4 T 3.0 4.0 4.5 3.

IR44ITA230

graded acidity levels. Tap water (EC 1.0, IR8067-41-1E-P1 2.7 6.3 7.0 6.5 6.0 s 2.5 2.5 2.0 2.

pH 7.2) was used as the medium. RD15 3.3 6.2 6.3 6.7 5.3 4.5 4.5 2.0 2.

Solution pH was adjusted to 1.0, 2.0,CSR4 0.5 6.0 6.3 5.5 5.8 9.0 9.0 11.0 6.

CROP AND RESOURCE MANAGEMENT

Soils and soil characterization

Influence of soil texture on Influence of soil type on root production andrice crop performance

grain yield. Tamil Nadu, 1983.

Root dry weight

M. A. Salam, Cropping Systems Research (g/pot) Grain

Centre, Karamana 695002, Trivandrum; and yield

S. Subramanian, Tamil Nadu AgriculturalTillering Panicle (g/pot)

University, Coimbatore 641003, Indiainitiation

Sandy clay loam 3.43 6.44 15.7

We studied the performance of IR20 Clay loam 3.98 7.39 21.1

rice in two soils of different textures inLSD (0.05) 0.14 0.17 0.4

CV (%) 7.3 5.3 2.4

pot culture under natural light during Difference 0.6 1.0 5.4

summer 1983 (Feb-Jun). % increase 16 15 34

~

The soils were clay loam (42.4% clay,

The crops received standard

management practices and

recommended nutrients. Root dry

weight was recorded at tillering and

panicle initiation. Grain yield wasmeasured at 14% moisture. The

differences in root production and grain

yield are given in the table.

Root production and grain yield were

higher in fine textured clay loam than in

coarse textured sandy clay loam. Grain

yield and root dry weight had significan

positive correlation.

The better performance of rice in clay

loam soil was due to enhanced root

production.

30.2% silt, 23.4% coarse sand, 4% finesand, 99-8-254 ppm available NPK, 0.7

ppm DTPA extractable Zn, 1.0% The International IPM Newsletter is published for researchers in the development and

organic C, pH 8.2, and EC 0.3 dS/m) transfer of integrated pest management (IPM) technology in rice production. Its content

and sandy clay (23.6% clay, 6.8% silt, focuses on discussions of current issues; it does not publish research reports. For more

26.5% coarse sand, 37.2% fine sand, information, write Dr. B. M. Shepard, IPM Newsletter, IRRI, P.O. Box 933, Manila,

100-4-140 ppm available NPK, 0.4 ppm Philippines.

DTPA extractable Zn, 0.42% organic C,

pH 7.8, and EC 0.17 dS/m).

IRRN 13:2 (April 1988) 1


16/28

Soil microbiology and biological N fertilizer was tested in the field.isolated and tested. One culture (TCSR

Early, uniform stem

nodulation in Sesbania

rostrata after spray of

Rhizobium culture

A. S. Bhagwat, D. C. Joshua, and C. R.

Bhatia, Nuclear Agriculture Division,

Bhabha Atomic Research Centre, Trombay,

Bombay 400085, India

Sesbania rostrata plants grown in pots

filled with local Trombay soil did not

produce any stem nodules. Plants raised

in pots filled with a mixture of local soil

and soil from Paddy Breeding Station,


Coimbatore, or inoculated with

homogenized stem nodules nodulated

profusely.

Those fully grown stem nodules were

removed, cleaned in tap water, surface-

sterilized with 0.1% HgCl2 for about

4 min, and washed in sterile distilled

water. The nodules were crushed,

inoculated in Luria broth (tryptone 1%,

yeast extract 0.5%, and NaCl 0.5%), and

incubated at 28 C. After 48 h, the

culture was plated on Congo red yeast

extract mannitol agar. Colorless

mucoid, slow growing colonies were

For field inoculation, culture grown

in Luria broth (about 10 8 cells/ml) wa

sprayed on 35-d-old S. rostrata (25

plants with 4 replications). At this stag

plants were 75-80 cm tall and had no

stem nodules.

Nodules developed on inoculated plants within 10 d. Stem nodules on 5

plants from each replication were

counted 20 d after inoculation.

repeatable nodulation. At 55 d after

sowing, the mean number of stem

nodules on inoculated plants was

180+16, compared to 22+4 in control

plants. This culture is available on

request.

The rhizobia1 culture induced early,

Physiology and plant nutrition N benefited uptake of N, P, K, Zn,

Influence of nitrogen and zinc

application on nutrient uptake

by rice in different seasons

M. A. Salam, Kerala Agricultural

University, Cropping Systems Research

Centre, Karamana 695002; and S.

Subramanian, Tamil Nadu Agricultural

University (TNAU), Coimbatore 641003,

India

We studied the uptake of major and

micro nutrients by rice in three seasons:

1982 southwest monsoon Jun-Oct, 1982

northeast monsoon Oct-Jan, and 1983

summer Feb-Jun. The experiment was

laid out in a factorial combination of 4

levels of N (0, 60, 90, and 120 kg N/ha)

and 2 levels of Zn (no ZnSO4 and 25 kg

ZnSO4/ha) in a randomized block

design with 6 replications, in a different

field each season.

The soil at TNAU (11 N, 77 E and

427 m above mean sea level) was a

Vertisol (clay loam) containing 1.1%

organic C, 196-9.5-200 ppm available NPK, 598 ppm total soil N, and

0.4 ppm DTPA extractable Zn. The test

variety was IR20. Standard

management practices were used.

Nutrient uptake was estimated using

standard procedures.

Fe, Mn, and Cu in all seasons; in

general, the effect persisted up to 90 kg

N/ ha (see table). Zn also increased N,

Zn, and Fe uptake in all seasons. This

can be ascribed to the positive effect of

Zn on root dry weight and root volume

(data not given).

N up to 90 kg/ ha and ZnSO4 at

25 kg/ ha increased grain yield in all

seasons. Simple regressions and

coefficients of determination revealedsignificant positive correlations in all

seasons.

A comparison between seasons

showed that uptake of N, P, K, Zn, Fe

Mn, and Cu was low during northeast

monsoon season.

N-Zn interactions were not consisten

Nutrient and micronutrient uptake by season.a TNAU, Coimbatore, India, 1982-83.

N uptake (kg/ha) P uptake (kg/ha) K uptake (kg/ha) Zn uptake (g/ha) Fe uptake (kg/ha)

SWM NEM SUM SWM NEM SUM SWM NEM SUM SWM NEM SUM SWM NEM SU

N and Zn levels

N0 67 46 57 18 13 19 74 74 132 137 N60 87 55 79 2116 19 96

97 146 1.18 0.53 1.95 117 208 159 217 1.68 0.97 1.

N90 96 60 89 22 18 22 101 136 143 209 168198 1.62 1.10 1. N120 104 70 91 21 17 23 162 142 164 239 181211 2.00 0.97 1.

LSD (0.05) 7 7 8 2 1 4 25 20 22 21 16 22 0.17 0.12 0.

Zn0 84 53 76 18 15 19 101 106 131 185 126 180 1.45 0.84 1.

Zn 1 93 63 81 23 17 22 115 117 146 212 162 206 1.77 0.95 1.

LSD (0.05) 5 5 ns 1 1 3 ns ns ns 15 12 16 0.12 0.08 0.

aSWM = southwest monsoon, NEM = northeast monsoon, SUM = summer.

16 IRRN 13:2 (April 1988)


17/28

Effect of farmyard manure

(FYM) supplemented with N,

P, K on grain yieldG. B. Chettri and R. B. Rai, Centre for

Agicultural Research and Development

(CARD), Wangdiphodrang, Bhutan; and

A. R. Samiano, Training and Technology

Transfer Department, IRRI

FYM is an important source of plant

nutrients for irrigated rice in Bhutan. Inthe Wangdiphodrang-Punakha valley,

FYM is predominantly composed of

animal manures mixed with rice straw invarious stages of decomposition. An

estimated average of 7 t FYM (fresh

weight)/ha is applied before

transplanting. The actual rate varies

widely, from zero to 20 t/ha.

As fertilizer-responsive rice varieties

become more widespread, FYM

probably will continue to contribute

significantly to crop nutrition and soil

condition.

We supplemented FYM with N, P, K

to evaluate its effect on grain yield of

IR36. IR36 seedlings raised in dry bed

nurseries were transplanted in mid-Junat 49 d after seeding with 20- 20-cm

spacing in 4- 6-m bunded plots, in a

completely randomized block design

with 7 treatments and 3 replications.

The soil was a loam with pH 6.6,

1.2% organic C, 9.3 meq CEC/100 g,

4.6 ppm available P (Olsens), 0.332 meq

Crop management

Environmental limitations to

rice cultivation in the Punjab

J. S. Sawhney and K. R. Sharma, Soils

Department, Punjab Agricultural University,

Ludhiana 141004, India

Five sites representing typical rice-

growing areas of the Punjab were

selected to evaluate suitability for rice

production. On the basis of soil-site

characteristics (see table), four suitability

classes have been defined, from highly

suitable to currently not suitable.

Average rice yields under controlled

conditions with fertilizer (50-12-12 kg

NPK/ ha) based on soil test suggest that

the yield data correlate well with soil-

site suitability class.

Punjab is controlled by rainfall during

growing season, soil texture, drainage,

infiltration, soil reaction, and soluble

salts. It is possible to make yield

predictions at different levels of the

suitability class on the basis of soil-site

The yield potential of rice soils in the

characteristics and their degree of

limitation. The study predicts the

following environmental limitations for

sustained rice cultivation:

Rainfallless than 300 mm during

Soil typefine loamy surface and

growing season Jul-Sep is limiting.

subsurface texture with more than

16% clay.

Drainageoptimum from moderately

well to imperfectly drained.

Soil reactionoptimum pH 7-8.3.

Soluble saltssalinity and alkalinity

are the primary obstacles.

Soil and site suitability characteristics and their limitations.a Ludhiana, India.

Soil

Rainfall Water

(annual) cumulativeJul-Sep (mm)

(mm) intakeDrainage pH

6h

Rawalpindi clay loam 202 29 Imperfect 8.6

(Aquic Ustochrepts) (315) (8.4)

Degree of limitation 2 0 0 1

Samana sandy loam 474 58 Well 7.4

(Udic Ustochrepts) (680) (7.6)


Bhoewal loam 532 42 Moder- 7.4

(Typic Haplustalfs) (7 13) ately well (8.2)


Narike sandy loam 290 40 Moder- 9.4

(Natraquic Calciorthid) (425) ately well (9.3)


Gurdaspur loam 603 48 Moder- 7.2

(Udic Haplustalfs) (88.6) ately well (7.3)


10-3 sodium Silt Clay

ECe Exchangeable

dS/m percentage

1.6 15.6

(1.7) (9.3)

1 2

1.0 6.9

(0.7) (6.6)

0 0

1 .0 7.4

(0.8) (8.2)

0 0

2.4 40

(3.6) (43)

3 4

0.4 2.5

(0.4) (1.1)

0 0

41.5 30.0(33.0) (34.1)

0 0

18.8 12.7(29.9) (15.7)

2 2

50.3 25.9(48.8) (29.2)

0 0

20.6 18.2(29.7) (22.8)

0 1

30.6 10.4

(40.7) (15.7)

0 0

Yield (t/ha)OrganicOverall

Land

Climitation

suitability Control Recommende

(%) classb fertilizer base

on soil-teste

0.45 1-2 S2 3.7(0.22)

6.1

0

0.35 2-3 S3 2.8 5.1(0.17)

1

0.72 0-1 S1 4.6(0.26)

0

0.17 3-4 S4 1.2 1.7

7.8

(0.12)

2

0.59 1-2 S1-2 4.1 7.4

(0.29)

0

aValues in brackets indicate weighted mean of the column. bS1 = highly suitable, S4 = currently not suitable. cAverage of 5 yr.

Soil fertility and fertilizer management

IRRN 13:2 (April 1988) 17


18/28

K/100 g, and 1.2 ppm available Zn. The

FYM contained 1.8% N and 0.45 pprn

total P. FYM, all P and K, and 35 kg

N/ ha were applied basally; the

remaining N was topdressed at panicle

initiation. Grain yield was computed at

14% moisture.

No significant pest or disease damage

or water stress occurred during crop

development. All fertilizer treatmentsincreased yield significantly (see table).

Mean yield from plots given FYM alone

was 20% higher than check plots.

Supplementing FYM with extra N had

no effect. FYM plus P significantly

increased yield 18% over FYM alone.

Yields with FYM supplemented with

Phosphorus requirements in a

rice - wheat cropping system

J. S. Kolar and H. S. Grewal, Agronomy

Department, Punjab Agricultural University,

Ludhiana 141004, Punjab, India

We studied P requirements of rice

grown in sequence with wheat in the

field 1983 to 1987. Different

combinations of P level (0, 13, and

26 kg P/ ha) and P application (applying

P to rice alone, wheat alone, or both

rice and wheat) were laid out in a

randomized block design with 4

replications.At the beginning of the experiment in

1983, the soil (sandy loam, Typic

Ustochrept) had pH 8.1, 0.29% organic

C, and 14.5 kg Olsen's P/ha. All plots

received 120 kg N and 23 kg K/ha. All

Effect of two phosphorussources with or without azolla

incorporation on rice yield in

the Senegal River valley

H. F. Diara and I. Camara, West Africa

Rice Development Association (WARDA)

Regional Research Station on Irrigated Rice,

Saint-Louis, Senegal

We compared a soluble-type P (triple

superphosphate with 45% P2O5 ) and a

natural type P (aluminum phosphate

18 IRRN 13:2 (April 1988)

N+P and from plots fertilized with

N+P or N+P+K only did not differ

significantly from yields with FYM+P.

nitrogen in FYM may be seriously

limited by inadequate soil P. In

Wangdiphodrang-Punakha, soil

analyses now show that available P

levels are generally low (less than 10

ppm). Available K and other plantnutrients appear to be adequate. These

preliminary results suggest that in a

region where use of inorganic fertilizer is

very low but use of FYM is routine,

more benefit could be obtained from

supplementing FYM with P.

The results indicate that utilization of

Effect of FYM supplemented with N and P o

yield of IR36. CARD, Wangdiphodrang, Bhuta

1986.

Fertilizer treatment a Grain

FYM b Nyield

P K (t/ha)(t/ha) (kg/ha) (kg/ha) (kg/ha)

0 0 0 0 4.8 7.5 0 0 0 5.8 b7.5 35 0 0 5.3 bc

7.5 0 50 0 6.9 a7.5 35 50 0 7.0 a00

75 50 0 6.6 a75 50 40 6.9 a

CV (%) 4.5

a N as urea, P as single superphosphate, K muriate of potash. b Fresh weight. c Meseparation in a column by DMRT at the 5level.

Influence of P on rice yield in a rice - wheat cropping system. Punjab, India, 1983-87.

P (kg/ha) Grain yield (t/ha)

Rice Wheat 1983 1984 1985 1986 1987 Mean

1984-8

0 013 026 0

0 130 26

13 1313 2626 1326 26

LSD (0.05)

7.4

7.37.57.56.87.1

7.57 .07.5

ns

5.7

6.86.96 .06.06.7

6.86.86.6

0.7

6.2 6.47.2 8.47.2 8.4

6.5 7.26.5 7.37.4 8.37.2 8.47.1 8.37.1 7.9

0.4 0.9

5.68.48.6

6.87.68.58.68.57.4

0.7

6.07.77.8

6.66.87.77.87.77.2

0.7

P and K and 1/3 N were applied before table). Rice grown on the residue oftransplanting. The remaining N was 25 kg P/ha applied to the preceding

applied at 21 d and 42 d after wheat showed no response. Increasing

transplanting. to 26 kg/ha for both rice and wheat

application of up to 13 kg P/ ha (see

Rice responded significantly to direct slightly depressed rice yield.

Soil analysis. Fanaye P4 (Paleustollic Torrerts), Fanaye Station, Senegal.

pH Organic CEC c Available P TotalAdsorbed P e a

Texture a Clay Sand SiltSoil:water KC1 (%) (%) (%) (%)

matterb (meq/ BRAY II Pd

the soil solutio

(1:1) 1 N100 g) (ppm) (ppm)

(g P/g of soil

6.2 4.4 Clay 46.5 29.9 23.6 0.35 31.26 1.50 240 330

a Bouyoucos method. bWalkley - Black method. c Cobaltihexamine method (Orsini et Remy 1976d Perchloric acid digestion. e Fox and Kamprath method (1970).

with 34% P2O5 ). We also evaluated the The trial for four consecutive

influence of azolla incorporation on cropping seasons was conducted on a

assimilation of P by rice. fine clayey soil Paleustollic Torrerts (se

0.2 ppm P in


19/28

Effects of 2 P sources, applied with and without azolla incorporation, on grain yield of rice variety Sri Malaysia.

Fanaye Research Station, Senegal River valley, 1985 rainy season. Basal appl ication of P, except in treatmen

6, where P was split-applied.

table). The design was a randomized

complete block with three replications.

Treatments were no N or P, no N plus

either of the 2 sources of P at the rate of

52 kg P/ha, 120 kg N (urea) plus either

of the 2 sources of P at 52 kg P/ha, and

60 kg N (urea) + 60 kg N (azolla)/ha

and O or 52 kg P, applied either split or

all at once. Two crops ofAzolla pinnata

var. imbricata, of Indian origin (20 t/haeach, equivalent to 30 kg N/ha) were

grown successively and incorporated

before rice transplanting. The rice

variety was Sri Malaysia.

After the third cropping season, rice

yield showed no influence from P. After

the fourth cropping season, during the

1985 rainy season, no significant

difference in yield between the two P

so urces had occurred (see figure).

equivalent with triple superphosphate,

yields were higher when azolla wasincorporated. Uptake of P from a split more pronounced with aluminum the fourth cropping season, the lack of

application and assimilated by azolla phosphate; the split application P had caused an important yield

seems better. The response of rice was produced 0.9 t/ha more. By the end of reduction (2.0 and 3.0 t/ha).

However, although N and P levels were

Disease management

Four fungicides for control of

grain infection caused by

Helminthosporium oryzae

A. S. Prabhu and A. B. Santos, National

Research Center for Rice and Beans

(EMBRAPA/CNPAF) - Caixa Postal 179,

74000 Goiania, Goias, Brazil

Grain discoloration caused by

Helminthosporium oryzae Breda de

Haan, the causal agent of brown spot

(BS), is a major problem in the 35,000

ha irrigated Rio Formoso rice project. A

disease outbreak in Feb 1983, during the

vegetative phase of the fourth successive

planting of lowland rice variety IAC899

in CNPAF experimental fields

indicated the possible role of infected

plant debris. Despite 3 sprayings with

maneb fungicide at 10-d intervals to

control leaf infection, the disease

retarded plant growth.

We evaluated four marketed spray

fungicides for grain infection control in

the same fields. The experiment used 8

m2 direct seeded plots in a randomized

block design with 8 replications.

Fungicides were sprayed at

recommended doses 3 times at 7-d

intervals, beginning at 50% heading

(92 d after seeding). Untreated controls

were not maintained because in similar

experiments, sprayed plots adjacent to

untreated plots exhibited abnormally

high disease intensities.

Effect of fungicide spray on BS control.a Goiania, Goias, Brazil, 1983.

FungicideFlag leaf lesions (no./leaf) Diseased grains/panicle (%) Unfilled grains/ Grain

112 DAS 119 DAS 108 DAS 115 DASpanicleb yield

(%) (t/ha)

Rate(kg ai/ha)

Ziram 50% EC 1.5 8.91 a 27.47 a 27.76 a 44.58 ab 41.75 a 2.05 a

Thiophanate-methyl (20%) + 1.4 7.43 b 22.19 b 26.56 ab 45.64 a 41.16 achlorothalonil 50% WP

2.03 a

Maneb 80% WP 1.6 8.59 ab 23.26 ab 25.71 ab 39.52 b 38.70 a 2.22 a

Captafol 48% EC 0.96 9.14 a 25.91 ab 23.30 b 39.34 b 34.83 a 2.41 a

CV (%) 12.0 13.5 11.8 10.2 17.2 15.2

a Means of 8 replications. In a column, means followed by a common letter are not significantly different by Tukey test at the 5% level. DAS = days afte

seeding. bUnfilled grain percentage was based on 10 panicles/plot.

IRRN 13:2 (April 1988) 19


20/28

Disease intensity on flag leaves and

panicles, unfilled grain percentage, and

grain yield were measured. Flag leaf

lesion counts and percentage of diseased

grains/panicle were based on 50

randomly collected tillers/ plot.

Distribution and severity ofrice seedling diseases in boro

seedbeds in Bangladesh

A. H. Mondal, M. M. Rahman, and S. A.

Miah, Plant Pathology Division, Bangladesh

Rice Research Institute, Joydebpur, Gazipur,

Bangladesh

We surveyed rice seedbed diseases in

some northwestern districts during the

Nov-Mar boro season. Six diseases

bakanae (Bak), blast (Bl), brown spot

(BS), damping-off (DO), root knot(RK), and seedling blight (Sb)were

found in 48 locations. Commonly grown

rice were BR1, BR3, BR8, BR9, IR8,

Pajam, Purbachi, and some local

varieties.

DO was found everywhere,

irrespective of variety (see table). RK

was the second most common disease; it

was not found in alkaline belts of

Rajshahi district. Its intensity and

severity were highest in sandy soil,

especially near riverbanks, even in

seedbeds with little standing water,irrespective of varieties sown.

BS was found in seedbeds that

suffered from water stress. Bak affected

seedlings of Purbachi, Khaily boro

(local cultivar), and BR16. Bl was found

mainly on Pajam and Iratom seedlings.

Treatments differed significantly, but but differences among the test fungicid

did not reduce flag leaf and grain were not significant. Blotter test

infection much (see table). Grain determined that 75% of seeds collectedinfection was negatively correlated with from sprayed fields were associated w

percentage of unfilled grain (r = H. oryzae. That seed lot showed only

-0.84**) and grain yield (r= -0.84**), 39% germination.

Distribution of seedling diseases as observed in boro seedbeds during January 1987 in northwest

districts of Bangladesh.

Disease frequency in survey areaa

Bak Bl BS DO RK Sb T

District

Bogra

Dinajpur

Gaibandha

Gazipur

Jamalpur

Lalmonirhat

Mymensingh

Natore

Pabna

Rajshahi

Rangpur

Tangail

Total

DI

6(18.2)

0

2(25.0)

0

1

(12.5)1

(33.3)2

(11.8)1

(11.1)0

0

2(14.3)

0

15(11.0)

4 [3-5]

0

0

0

2

(12.5)0

0

3

(17.6)0

0

0

1

(7.1)3

(16.7)

9

(6.6)

8 [7-9]

6(18.2)

0

2

(25.0)1

(25.0)1

(12.5)0

3

(17.6)3

(33.3)3

(37.5)2

(33.3)1

(7.1)2

(11.1)

24

(17.6)

5 [3-7]

12(36.4)

2(50.0)

2

(25.0)2

(25.0)3

(37.5)1

(33.3)6

(35.3)3

(33.3)4

(50.0)2

(33.3)5

(35.7)6

(33.3)

48(35.3)

6 [ 3-9]

9(27.2)

2(50.0)

2(25.0)

2

(25.0)

3(37.5)

1(33.3)

3(17.6)

2

(22.2)1

(12.5)1

(16.7)5

(35.7)7

(38.9)

38(27.9)

5 [3-7]

0

0

0

1(12.5)

0

0

0

0

0

1

(16.7)0

0

2

(1.5)

3 [ 1-5]

3

l

13

a Figures in parentheses show percentage of the disease in the district; those within brackets showdisease index. DI 1 = lowest disease intensity, 9 = highest disease intensity.

Severity as high as disease index 8 was found in only two locations. More tha

concentrated in Mymensingh, Tangail, one disease was observed in the same

Gazipur, and Rangpur districts. Sb was seedbed in some locations.

Managing rice sheath rot

(ShR) disease in Kerala, India

B. K. Nair, Agriculture Department, Kerala;B. Balakrishnan, Regional Agricultural

Research Station, Kumarakom, Kottayam,

Kerala; and M. C. Nair, Plant Pathology

Department, College of Agriculture,

Vella-vani, Kerala, India

Field trials to evaluate crop nutrition

schedules for managing rice ShR disease

20 IRRN 13:2 (April 1988)

have shown that sources of N and

method of application can influence

disease incidence and grain damage.

A field experiment during the firstcrop season (May-Sep 1985) at the

Cropping Systems Research Centre,

Karamana, used susceptible variety

Jyothi to evaluate crop nutrition

schedules for managing ShR.

The fertilizer level used was 70-35-

52.5 kg NPK/ ha, the recommended rate

in disease endemic areas. Sources were

farmyard manure (FYM), urea, and

ammonium sulfate for N; super-

phosphate for P; and muriate of pota

for K. Except for FYM, all forms of Nwere applied in three splits, half as bas

and half in two equal topdressings. K

was applied in two equal splits, basal

and as topdressing. All P was applied

basal.

Carboxin (0.1% spray), widely

recommended for ShR control, was

sprayed with two fertilizer treatments


21/28

Effect of fertilizer and organic manure on ShR intensity and rice grain yield. Kerala, India, 1985.

Disease intensitya Grain yield (t/ha)

Treatment Without With Without With

fungicide fungicide fungicide fungicide

(F0) (F1) (F0) (F1)

Organic manure (OM) 4.9 3.5 3.0 2.8alone @ 5 t/ha in soil

at planting

OM + N1

(urea) and K 6.7 5.0 4.6 4.6

soil application

OM + N2 (ammonium 7.5 4.5 4.4 4.5sulfate) and K soil application

OM + N1 and K, last split 5.9 5.9 4.6 5.0of both N and K as foliar sprays

OM + N2 and K, last split 4.1 8.1 4.4 4.6of both N and K as foliar sprays

OM + N1 + K + Zn and Mn 8.2 6.1 4.6 4.7

foliar sprays

OM + N2 + K + Zn and Mn 9.2 6.7 4.4 4.5

foliar sprays

LSD for treatment (T) 2.1 197.1

LSD for T fungicide 3.0

a

By the Standard evaluation system for rice 1 to 9 scale.

45 and 60 d after transplanting.

Five random 1-m2 samples were

observed in each 24-m2 plot. Each hill

was scored on type and

Documents

International Rice Research Newsletter Vol.13 No.2