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

shoot fly resistance QTLs (once these had been confirmed) in these genetic backgrounds and then developing malesterile
lines from the QTL introgression lines].
Output target 5A.2: A diverse range of trait-specific sorghum breeding lines and populations with
morphological diversity and resistance to shoot fly, stem borer and grain mold (2011)
Activity 5A.2.1: Generating new breeding lines with resistance to disease and insect pest resistance, and
mapping of QTL and assessment of their effects on resistance levels for these traits
Milestone 5A.2.1.1: Forty F 4 lines developed for resistance to each of grain mold and shoot fly (BVSR/RPT/HCS/RS,
2008)
Grain mold resistance: A total of 200 F 4 s derived from the crosses between grain mold resistant B-lines and highyielding
lines were screened for GMR [panicle grain mold rating (PGMR) score taken on 1 to 9 scale where 1 = no
mold or 90%] in a nursery during the 2006 rainy season. These were also evaluated and testcrossed
onto A 1 and A 2 CMS systems in breeding nursery during the 2006 rainy season. The data from the screening nursery
are awaited. From the breeding nursery, 51 F 5 s tolerant to grain mold (PGMR ≤5) and desirable agronomic traits
were produced and harvested along with their testcrosses for assessing their maintainer/restorer reaction.
BVS Reddy and RP Thakur
Shoot fly resistance
Shoot fly resistant maintainers: 12 F 5 s derived from the crosses between shoot fly resistant maintainer lines and
high-yielding breeding lines (as set 3) were screened for shoot fly resistance in screening block and also evaluated in
breeding block for testcrossing in the 2006 rainy season. The deadhearts ranged from 41 to 88%. The resistant
control – IS 18551 showed 20% and susceptible control – 296 B showed 87% deadhearts. Corresponding 47
progenies with testcrosses (22 on A 1 , 25 on A 2 ) in the breeding block which showed below 65% deadhearts were
selected for continuing the conversion program.
Shoot fly resistant maintainers (postrainy season): In the 2005 postrainy season, 80 F 4 s, 174 F 5 s, and 17 F 6 s with
postrainy season adaptation were screened for SFR in a screening block and also advanced in breeding block for
testcrossing onto A 1 and A 2 CMS systems-based male-sterile lines. Based on deadheart % (below 57%) in the
screening block, 203 F 5 progenies (with 28 testcrosses on A 2 , 118 testcrosses on A 1 and A 2 and 57 yet to be
testcrossed) from 80 F 4 s; 166 F 6 progenies (14 testcrosses on A 2 , 101 testcrosses on A 1 , A 2 and 51 to be testcrossed)
from 174 F 5 s; and 20 F 7 progenies (11 testcrosses on A 1 and A 2 and 9 to be testcrossed) from 17 F 6 s were produced.
These testcross parents along with 27 stabilized B-lines are being evaluated as four separate sets for SFR in
screening and breeding blocks in the 2006 postrainy season.
BVS Reddy and HC Sharma
Restorer lines evaluated for resistance to sorghum shoot fly, Atherigona soccata: Over 50 F 6 lines were screened
for resistance to sorghum shoot fly, A. soccata during the 2006 rainy season along with resistant (IS 18551) and
susceptible (296B) checks in a randomised complete block design with three replications. Deadheart formation
ranged from 10.7 to 58.4%, and 11 lines suffered