Mutation studies in mung bean (Phaseolus aureus). V. Induced polygenic variability after seed irradiation

Abstract

Studies were undertaken to explore the possibility of inducing micromutations in quantitative characters of mung bean (Phaseolus aureus Roxb.) after seed irradiation. The characters studied were as follows: pod length, seeds per pod, 100-seed weight, and total plant yield. These characters were analyzed quantitatively to assess the extent of variation in M1, M2, and M3 generations. All characters varied significantly [Formula: see text] in the M2 generation. In the M3 generation, pod length, seeds per pod, and 100-seed weight were found significant at the 1% level; plant yield was only significant at 20 and 40 kR (1R = 2.58 × 10−4 C/kg) of gamma rays. Gamma ray treatments shifted the mean values of all characters, mostly in a positive direction in the M2 and M3 generations. The range of variability also increased positively. There was a considerable increase in genotypic variances, heritability, and genetic advances indicating the effectiveness of gamma doses in inducing polygenic mutations governing quantitative traits. The genetic variability increased at all dose levels but it was not linear with dose. Estimates of heritability and genetic advance increased in all characters but the different traits responded differently to the mutagenic treatments.