D Rajarajan, R.Saraswathi, D. Sassikumar, S.K Ganesh
A field experiment was conducted to study the effect of gamma rays and Ethyl Methyl Sulfonate (EMS) in rice variety ADT (R) 47. The frequency and spectrum of chlorophyll mutations, mutagenic effectiveness and efficiency, mutation rate of physical mutagen over chemical mutagen were estimated at different levels to study the nature and effect of mutagens in rice. The result from the study indicated that, albino was the predominant class of chlorophyll mutants that occurred in M2 generations at lower doses. The mutagenic effectiveness and efficiency were found to be higher at 200Gy of gamma irradiation and 120mM of EMS. The mutation rate of gamma rays (0.57) was higher in terms of effectiveness than that of EMS (0.15). In terms of efficiency, the mutation rate of gamma rays was higher based on injury (4.84), lethality (2.55) and sterility (6.29). It could also be observed that increase in dose or concentration of the mutagen did not increase the relative frequency of chlorophyll mutants.