Abstract

                                Physical and chemical mutagens have been used to raise the genetic variation in most of the crop plants. An experiment was conducted to study the effect of gamma rays and Ethyl Methyl Sulfonate (EMS) in two quality rice genotypes of improved White Ponni and BPT 5204. In this study frequency and spectrum of chlorophyll mutations, mutagenic effectiveness and efficiency and mutation rate were estimated. The result from the study indicated that, albino was the predominant chlorophyll mutants that occur in M2 generations of improved White Ponni and BPT 5204 at lower doses. The mutagenic effectiveness and efficiency were found to be higher at 100Gy of gamma radiation in both the varieties. The mutation rate of gamma rays (0.7131) was recorded high in improved White Ponni whereas, mutation rate of EMS (0.6693) was found to be higher in BPT 5204. In terms of efficiency, the mutation rate of gamma rays was registered to be higher based on injury (6.6587) and sterility (13.8777).

Key words : Rice, Gamma rays, Ethyl Methyl Sulfonate, Mutagenic effectiveness, Mutagenic efficiency and Mutation rate.