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

The comparison of A × R and B × R crosses (in both A 1 and A 2 backgrounds) indicated that while A × R (both A 1
and A 2 ) crosses were significantly early (by 1 day in both A 1 and A 2 backgrounds for days to 50% flowering) and
significantly taller (by 0.2 m in A 1 and by 0.2 m in A 2 backgrounds), B × R crosses manifested higher grain yield (by
0.1 t ha -1 than A 1 and by 0.2 t ha -1 than A 2 cytoplasm) when average performance of A 1 and A 2 -based A × R and B ×
R hybrids as separate groups was considered.
Significant cytoplasmic effects were observed for all the traits when individual nuclear genetic backgrounds of A × R
(both A 1 and A 2 ) and B × R crosses were examined. Significant cytoplasm effects were detected in some of the
nuclear genetic backgrounds for all the traits. While A × R crosses, besides being early, were taller compared to those
of B × R crosses in a majority of nuclear genetic backgrounds, the reverse was true for grain yield. These results were
not in conformity with those reported earlier, wherein A × R crosses were significantly superior to B × R crosses for
grain yield suggesting the need for repetition of the trials for onfirming these results.
BVS Reddy
Shoot fly resistance: The F 1 hybrids based on different male-sterile cytoplasms were tested for resistance to
sorghum shoot fly, A. soccata under field conditions using interlard fishmeal technique. Seventy-two hybrids and 12
restorers were tested for resistance to shoot fly under natural infestation. There were three replications in a
randomized complete block design. Data on shoot fly deadhearts were recorded at 18 days after seedling emergence,
when the differences between the resistant and susceptible checks were maximum. Shoot fly deadhearts ranged from
40.0 to 100.0% in the hybrids, and it was 28.8% in IS 18551, 84.8% in 296B, and 81.2% in CSH 16. Hybrids based
on ICSA 4 M were less susceptible than those based on other cytoplasms.
In another trial, 26 hybrids, 10 B-lines, and 10 restorers along with resistant, IS 18551 and susceptible, CSH 16
checks were evaluated for resistance to shoot fly, A. soccata. There were three replications in a randomized
complete block design. Data on shoot fly deadhearts was recorded at 18 days after seedling emergence, when the
differences between the resistant and susceptible checks were maximum. Shoot fly deadhearts ranged from 32.2 to
78.4% in the hybrids, and it was 46.1% in IS 18551, and 91.1% in CSH 16. Hybrids based on ICSA 425 and ICSA
452 were less susceptible than those based on ICSA 455, indicating the potential of using these lines for producing
shoot fly resistant hybrids.
HC Sharma and BVS Reddy
Activity 5A.4.2: Assessing the relationship between molecular diversity of parental and yield heterosis
Milestone 5A.4.2.1: Relationship between parental molecular diversity and hybrid heterosis assessed
(CTH/SPD/BVSR, 2009)
To be reported subsequently
Output target 5A.5: High-yielding and good combining sorghum hybrid parents developed for postrainy
season adaptation (2009)
Activity 5A.5.1: Developing high-yielding and good combining sorghum hybrid parents for postrainy season
adaptation
Milestone 5A.5.1.1: Five each of high-yielding and good combining sorghum male-sterile lines and restorer lines
for postrainy season developed (BVSR, 2009)
Several early-maturing advanced generation progenies derived from the crosses between postrainy season-adapted
varieties, high-yielding B-lines and landraces were evaluated during the 2005 postrainy season.
A total of 44 postrainy season-adapted F 6 progenies were evaluated and testcrossed onto A 1 –male-sterile line. From
these, 34 F 7 progenies were produced and their testcrosses were harvested. The selected progenies flowered in
76−86 days and had a plant height range of 1.3 to 2.1 m.
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