Advanced cluster bean mutant lines developed by treating seeds of Pusa Navbahar variety with gamma radiation were evaluated in randomised complete block design with two replications to study the genetic variability. The analysis of variance revealed highly significant differences among the mutant lines of cluster bean for all the characters studied. The GCV and PCV values were high (>20 %) for number of vegetable pods per plant, pod yield per plant, pod yield per plot, pod weight, dry pod yield per plant, seed yield per plant and seed yield per plot indicating the existence of broad genetic base, which would be amenable for further crop improvement. High heritability (>60 %) coupled with high genetic advance over mean (>20 %) were observed for characters viz., plant height, number of vegetable pods per plant, number of pods per cluster, pod yield per plant and seed yield per plant which indicated predominance of additive gene action for these traits and hence direct selection would be more effective in improving these traits.
