GAMMA IRRADIATED VARIABILITY STUDIES IN BAMBARA GROUNDNUT (Vigna subterranean (L.) Verdc.)
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Date
40600
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University of Agricultural Sciences GKVK, Bangalore
Abstract
The present investigation was under taken with the objectives of
determining the optimum dose of gamma rays for the variety SB-42,
assessing genetic variability in M2 generation and to know the correlation
and path coefficient between seed yield and its component characters. For
the present study, variety SB-42 of Bambara groundnut was irradiated
with the gamma radiation at doses of 150Gy, 175Gy, 200Gy and 225Gy.
Germination and survival per cent in M1 generation decreased with the
increase in doses of gamma radiation. Lower dose of 150Gy did not affect
the germination whereas germination was affected at 225Gy. Optimum
dose was found to be 200Gy for survival. In M2 generation, negative shift
in mean was observed for all the characters except days to flowering, but
shelling percentage and number of pods per plant showed positive shift in
mean at 150Gy and 175Gy. Correlation study in M2 generation revealed
that different doses of gamma rays are responsible for enhancing,
reducing or altering the correlation for the characters and thus provide
opportunity to improve yield. Number of branches per plant, pod yield per
plant and number of pods per plant showed highly significant correlation
with seed yield. From the path coefficient studies it was observed that the
characters which showed high positive correlation with yield may not exert
direct positive effect on the yield. Pod yield per plant followed by shelling
percentage (except at 150Gy) and number of pods per plant (except at
150Gy) exerted maximum direct effect on seed yield per plant. Significant
morphological variability was observed following gamma irradiation. One
early maturing, four double seeded plants and two high yielding mutants
were identified as economic mutants.