MSc

The research programme was carried out at the Department of Plant
Breeding and Genetics, College of Agriculture, VelIayani during rabi season 1998-99,
with the objective of identifying superior progenies in the F2 generation for
yielding ability and nitrogen fixation 'potential. Seven parents and F 2 progenies of
their 21 crosses of greengram were evaluated, adopting a randemised block design
with three replications. The data collected for thirteen quantitative characters
were analysed statistically. The genetic parameters, correlation and path
coefficients were studied and a selection index was formulated to identify superior
genotypes.
The treatments showed significant difference for all the characters. High
genotypic coefficient of variation was observed for weight of nodules in the root
at 50 per cent flowering, dry weight of plants at maturity, nitrogen content of
plants at maturity and grain yield. High heritability coupled with high genetic
advance was observed for weight of nodules in the root at 50 per cent flowering
followed by dry weight of plants at maturity, grain yield, number of pods, number
of cIuslters per plant, harvest index, hundred grain weight, number of secondary
roots at maturity, plant height and shoot/root ratio indicating additive gene action
and reliability of these characters during selection programme for crop
improvement.

High positive genotypic correlation for number of pods per plant followed
by number of clusters per plant, harvest index, plant height, hundred grain weight
and number of seeds per pod indicated selection based on one or more of the
above components may result in the improvement of grain yield. The path
coefficient analysis revealed high positive direct effects of number of pods on
grain yield. In addition hundred grain weight and number of seeds. per pod also
showed positive direct contribution to grain yield.
A selection index was constructed based on grain yield per plant and eight
yield contributing characters identified through correlation and path analysis.
Based on the selection index one of the parental varieties CoGG-902 ranked first
followed by Pusa-9333 x NDM-88-14, Pusa-9333, KM-1285 x CoGG-902 and
IlPRM-3 x LG-444 were identified as superior for yielding ability and nitrogen
fixing potential.