Variability, heritability, genetic advance and path analysis in yam bean (Pachyrhizus erosus L.)

Genetic variability in terms of mean, genotypic and phenotypic coefficient of variances, heritability, expected genetic advance as per cent of mean and path coefficient were studied for yield/plant and its attributing traits in 15 genotypes of yam bean. The phenotypic coefficient of variation was higher than genotypic coefficient of variation estimates for number of branches, mean number of germinated seeds and yield/plant. Heritability estimates were high for length of vine, number of nodes/plant, length of vine 30 days after sowing, mean number of branches and number of spikes. In spite of high heritability values for most of the traits, the expected genetic advance as percentage of mean ranged from 8.99 to 41.02. Path coefficient analysis revealed that number of pods set, length of vine 30 days after sowing and number of nodes/plant had maximum direct effect at genotypic level and hence direct selection could be made for these characters for improving the yield, while maximum direct effect at phenotypic level was showed by number of nodes/plant and length of vine 30 days after sowing. The number of branches, number of germinated seeds and number of flowers/plant showed maximum direct but negative effect on yield at genotypic level. The number of flower buds/plant showed maximum indirect positive effect on yield hence simultaneous selection for these characters can be made for improvement of yield.