Abstract

                                Seeds of the rice variety Co 37 were subjected to gamma rays and EMS alone and in combination with two treatments. The effects of frequency and spectrum were studied. The frequency of mutations estimated as number of mutants per 100 My spikes was as- efficient as the number of mutants per 100 M, plants. Gamma rays proved more potent in inducing chlorophyll mutations than EMS. The combination of treatments induced a higher frequency of chlorophyll mutations than individual treatments showing antagoni stic effect on M, spike and additive effect on M, seedling basis, Regarding the spectrum. of chlorophyll mutations gamma rays induced Albina, Xantha and Striate types, whereas EMS and combination treatments produced Virescent in addition to three types obtained through gamma rays. Albine and Xantha occurred more frequently than other types in all the treatments but the combination treatments produced more Albina than individual treatments.

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