Comparative efficiency of irradiation and its recurrent mutation on induced variability and population characteristics in rice (Oryza sativa L.)

The present study was carried out to elucidate the mutagenic efficiency of gamma rays (100 Gy, 150 Gy), electron beam (100 Gy, 150 Gy) used alone and in combination with EMS (30mM) as a recurrent treatment in the subsequent generation of Anna (R) 4 rice cultivar. The study was aimed to analyse the induced genetic variability, mean performance as well as population characteristics for various quantitative traits in M2 generation. The mutant lines were selected based on earliness, grain shape and yield. In general, bidirectional shift without any uniform trend was observed for all the traits except productive tillers per plant and grain weight. Recurrent EMS approach had no significant effect on earliness, however, it had significant effect on reduction of plant height (8.19%) and productive tillers per plant (25.27%) in EB 150Gy + EMS 30mM. Whereas 150 Gy gamma irradiation had increased effect on grains per panicle (21.99%), panicle weight (34.73%) and grain yield per plant (9.77%). Though selection was exercised for desirable traits, co-efficient of variation was still higher for productive tillers per plant (31.90%), grains per panicle (30.20%), panicle weight (30.87%) and grain yield per plant (31.55%). From the mean performance and population characteristics, it is concluded that recurrent EMS mutagenic approach was less efficient than irradiation for induction of desirable changes in earliness, grain shape, grain yield and other quantitative traits.