Gamma Rays Induced Mutation in Soybean [Glycine max (L.) Merrill]

In radio-sensitivity studies, there were significant differences between all soybean characters when different doses of gamma rays viz., 15, 30, 45, 60, 75, 90 and 105 kR were applied. The mean values for germination, root length, shoot length and number of secondary roots were lower than those of their respective controls, associated with an increase in the doses of gamma rays. Heat treatments (60°C for 12 h) were particularly effective at higher doses (60–90 kR) than cold and untreated treatments by protecting the seed populations against radiation damage. In the two cultivars tested, i.e. ‘Pusa 16’ and ‘PK 1042’, reduced germination was associated with an increase in the dose of mutagen in all three treatment groups. Varietal differences for germination, root length, shoot length, number of secondary roots and root shoot ratio were also observed in all the doses of gamma rays. A similar trend was also noticed for survival, seedling length and recovery index.