Two rice varieties namely TKM-6 and Norin-27 representing respectively indica and japonica sub-species of Oryza sativa treated with gamma rays and ethylmethane sulfonate were studied in the M2 and M3 generations for induced quantitative variation in respect of yield and its major components. Response of the characters to mutagen treatments was evident from the significntly increased variation in the treated populations as compared to their respective controls. The magnitude and the heritable portion of the induced variation were found to differ depending on the genotype, character and mutagen for a given generation. Similarly increase or decrease in the size of induced variation from M2 to M3 varied with the character and the variety. The observed tendency of the character mean in the treated populations has been discussed with rereference to the selection history of the character.
