ICRISAT Archival Report 2006 - The seedlings of success in the ...

Grain mold resistance in selections from B- and R-lines: Ninety-seven grain mold-resistant single plant
selections (33 from 14 B-lines and 64 from 24 R-lines from the 2005 screen) along with 4 resistant and 4 susceptible
checks were evaluated to confirm their resistance. The experiment was conducted in a RCBD with 2 replications, 1
row of 2 m long/replication. Sprinkler irrigation was provided twice a day for 30 min. each on rain-free days from
flowering to physiological maturity to provide high humidity (>90% RH) essential for mold development. The grain
mold scores were recorded at physiological maturity (PM) using a 1 to 9 scale, where 1 = no mold infection and 9
>75% molded grains on a panicle. The mean grain mold scores on test genotypes ranged from 2.0 to 7.8 compared
to 1.0−2.0 score on resistant checks (IS 14384, IS 8545 and IS 25017) and 8.8−9.0 score on the susceptible checks
(CSH 9, CSH 16, Bulk Y and SPV 104). Results indicated that 50 selections (23 from 8 B-lines and 27 from 10 R-
lines) were resistant (≤3.0 score). Some of these selections have been utilized in developing test hybrids.
Grain mold resistance in sorghum germplasm: One hundred fifty-six germplasm lines reported as resistant to
grain mold during 1985−87 along with two resistant and one susceptible checks were screened to find the stability of
resistance under field conditions. These were evaluated unreplicated with 2 rows of 2 m per entry. Sprinkler
irrigation was provided twice a day for 30 min. each on rain-free days from flowering to physiological maturity. The
visual grain mold scores were recorded at physiological maturity (PM). The grain mold scores of the test lines varied
from 1 to 7 compared to 1.0 to 2.0 on resistant checks (IS 14384 and IS 25017) and 9.0 on the susceptible check
(SPV 104). Of the 156 lines, 19 (IS 3413, IS 8848, IS 13885, IS 14375, IS 14380, IS 14384, IS 14385, IS 14387, IS
14390, IS 13756, IS 21599, IS 24995, is 24989, IS 24996, IS 25038, IS 25075, IS 25084, IS 25100 and IS 25105)
were highly resistant (1.0 score); 134 resistant (1.1 to 3.0 score) and 3 moderately resistant (3.1−5.0 score). Some of
the highly resistant germplasm lines from the 19 identified above having desirable agronomic traits would be useful
in breeding program to develop grain mold resistant hybrid parents.
Grain mold resistance in zerazera selections: Thirty-two selections from two zerazera conversion lines (IS
18758C and IS 30469C) and two susceptible checks were evaluated for grain mold resistance. The 34 entries were
grown in a RCBD with 2 replications, 1 row of 2 m per replication. The sprinkler irrigation was provided twice a
day for 30 min. each on rain-free days from flowering to physiological maturity. The grain mold scores were
recorded at physiological maturity (PM). Five (from IS 18758C) of the 32 selections were moderately resistant (3.4
to 4.3 score), while the remaining were susceptible (>6.0 scores). These five resistant selections are early maturing
with medium height and white grain and thus could be utilized in grain mold resistance breeding.
RP Thakur and Rajan Sharma
Milestone 5A.3.1.3: Relative contributions of host and environmental factors in mold development assessed
(RPT/RS/BVSR, 2010)
Host and environmental factors in relation to mold development: In the 2006 grain mold nursery, we evaluated
156 germplasm lines reported as resistant (during 1985−87) to confirm their resistance under changed environment
and screening procedure. These lines originate from different countries of Africa and possess diverse morphological
traits (such as panicle shape and size, grain color, glumes color and glumes coverage of grains) and agronomic traits
(plant height and days to flowering). In addition to grain mold severity, we obtained data on the above
morphological and agronomic traits. From these and other data sets from diverse breeding lines collected during the
past years we plan to determine the relative contributions of host and environmental factors to grain mold
development.
RP Thakur, Rajan Sharma and BVS Reddy
Activity 5A.3.2: Develop screening techniques and investigate host genotype - natural enemy interactions,
resistance mechanisms and genetics of insect pest resistance
Milestone 5A.3.2.1: Insect–host genotype - natural enemy interactions, and mechanisms of resistance and their
inheritance studied in sorghum (HCS/BVSR, 2009)
Physico-chemical mechanisms of resistance to sorghum shoot fly: Fifteen lines comprising of shoot fly-resistant
and -susceptible types were evaluated for resistance to Atherigona soccata under no-choice, dual-choice and multichoice
conditions in the field and glasshouse. There were three replications in a randomized complete block design.
Data were recorded on shoot fly oviposition, deadheart formation, recovery resistance, leaf glossiness score,
trichome density, insect survival and development, and fecundity. There were 5.11 eggs per 10 plants in IS 2146 to
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