RADIO SENSITIVITY OF RICE GENOTYPES TO GAMMA RADIATIONS BASED ON SEEDLING TRAITS AND PHYSIOLOGICAL INDICES

Three Basmati rice genotypes viz., 00515, 99417 and Super Basmati were examined for varietal differences in radio sensitivity to gamma radiations. Dry healthy seeds were exposed to variable doses of gamma radiations i.e., 150-400 Gy with 50 Gy intervals. Highly significant differences among the genotypes (p<0.01) for all traits were observed. The differences among radiation treatments were highly significant (p<0.01) for shoot and root length, shoot and root fresh weight, water uptake, chlorophyll contents (a, b), plant height and panicle fertility while non significant differences were observed for germination percentage only. The genotype x dose interactions were non significant for germination percentage, shoot length, root length, shoot fresh weight and plant height indicating stability of performance for characters across different radiation levels. In contrast, chlorophyll (a, b), root fresh weight, water uptake and panicle fertility exhibited significant differences for interactions. Mutagenic treatments shifted mean values towards negative direction for almost all traits but not in a definite pattern. However, water uptake of seeds increased with increasing gamma radiation doses. In general, genotypes displayed variable response towards gamma radiations.