Mutagenic induction of variability and selection in M2 generation of selected ricebean {Vigna umbellata (Thunb.) Ohwi and Ohashi} cultivars of Manipur

Induced variability studies and selection in M₂ generation were taken up in three ricebean cultivars, viz., RBM-6, RBM-13 and RBM-31 utilizing 5 gamma ray doses of 0, 150, 300, 450 and 600 GY. Two visually detectable dwarf mutants viz., RBM-6-2-4 and RBM-6-2-5 from the 300 GY gamma ray treated population of RBM-6 and one early maturing mutant, RBM-13-3-1 from 450 GY gamma ray treated population of RBM-13 were isolated in M₂ generation. The plant height at maturity of the two dwarf mutants were 57.60 cm for RBM-6-2-4 and 48 cm for RBM-6-2-5 as against 129.88 cm of the parental plant height. The duration of the early mutant RBM-13-3-1 was 120 days asagainst 154 days of the parent. High induced variability were observed for the characters viz., clusters per plant, pods per plant and grain yield per plant. High heritability with high genetic advance were estimated for 100 grain weight and seedling height. While medium heritability coupled with high genetic advance was observed for grain yield per plant.