Effect of gamma irradiations on seed germination, seedling growth and mutation induction in Cluster bean [Cyamopsis tetragonoloba (L.) Taub.]

Abstract

Cluster bean is an annual drought hardy legume crop mainly cultivated in arid regions receiving scanty (150-400 mm) and erratic rainfall during crop growth period. For the enhancement of genetic diversity in this locally adapted crop, three genotypes HG- 2-20 (hispid branched), CAZG15-6 (branched glabrous) and CAZG 15-3 (single stem, hispid and regular bearing) were irradiated with gamma rays (100 -1600 gray) with 100 gray intervals. The mutation rate increased with increasing dose up to 300 gray, there after gradually reduced indicating decline in rate of recovery of mutations with respect to increasing M1 damage. At higher dose of 800 gray, mutation efficiency drastically reduced with reduced survival and high level of pollen sterility in M1 generation. Beyond 800 Gy dose all the seedlings died within a few days (15 d) of germination. Based on mutation efficiency and effectiveness a gamma radiation dose between wide ranges (200-700 Gy) was found appropriate for inducing variability. The mutagenesis has generated, a good amount of diversity for economically and agronomically important traits.