INDUCED POLYGENIC VARIABILITY IN GREEN GRAM (VIGNA RADIATA (L.) WILCZEK) AND SCOPE OF SELECTION

The present investigation was undertaken with a view to estimate the nature and extent of genetic variability induced by four doses of gamma irradiation in two green gram varieties namely TARM 1 and Sujata. Separately harvested M-1 plants were used to raise M-2 generation. Observations on seven quantitative traits were recorded on five randomly selected normal looking plants in each family of a treatment, and mean, range and CV for these traits were estimated. Results of the experiment indicated (i) variation in behaviour of means, (ii) widening of ranges and (iii) increase in coefficient of variation (CV) for all characters in mutagenic: treated populations as compared to their controls. The magnitude of CV was different for different treatments and characters in the two varieties. Of the seven characters studied, induced variability was higher for pod length, pods/plant and seeds/pod suggesting scope of improvement through selection in these characters. Between the two varieties, improvement of Sujata appears more promising than TARM 1 due to induction of more positive mutations in important economic traits.