Induced mutations in foxtail millet (Setaria italica Beauv.) : II. Viable mutations in ear characters induced by gamma rays, EMS and dES.

Viable mutations for ear characters in two cultures of foxtail millet (Setaria italica Beauv.) were induced by individual and combined treatments of gamma rays, EMS (ethyl methanesulphonate), and dES (diethylsulphate). Four doses of gamma rays (10Kr to 40Kr), and four durations (6hrs to 24hrs) each of EMS (0.1 %) and dES (0.1 %) were used. In the combined treatments, only two durations (6hrs, 12hrs) of the chemical mutagens were used following each of the four doses of gamma rays.The mutation frequencies were recorded as mutants per 100 M2 plants and these were found to be higher in MU-1 than in MU-2 in all the treatments except dES. The frequencies also increased with increase in dose or duration of treatments and were found to be much higher in the combined treatments than in the individual treatments. In several combined treatments, a synergistic effect was observed in culture MU-1, the degree of synergism ranging from 1.01 to 1.62. Thus there was a differential response by the two cultures to the mutagenic treatments. The mutation spectrum was also found to be wider in culture MU-1, where 11 different kinds of mutants were recorded compared with only eight kinds of mutants recorded in MU-2.