P.S. Kharate, K.P. Panzade and Z. Jha
Abstract
The anther culture derived calli of rice varieties IBD-1 and MTU1010 were exposed to doses of 15 Gy and 25 Gy gamma irradiations along with control (without irradiations) to study effect of gamma irradiation on survivability of calli. The calli from the both varieties that had been exposed to gamma radiation were placed on MS media supplemented with BAP, Kin NAA and 3% sucrose. In the control of (without irradiations) IBD-1 and MTU1010 exhibited the high calli survival rate i.e. 70% and 56% respectively. But in case of IBD-1 calli, gamma ray dose of 15 Gy was causing 46% reductions in survival rate and in case of the MTU1010 calli the survival rate was reduced to 38% for 15 Gy dose. At higher dose of 25 Gy gamma ray, the survival rate of calli is very much affected in the variety IBD-1 with 22% reduction and 16% reduction in MTU1010 variety. The callus from IBD-1 and MTU1010 showed the decreased survival rate after increased gamma irradiation. In the comparison of both varieties the clear pattern of proportional decrease of survival rate of calli to increased dosage of gamma irradiation was observed. The doses of 15 Gy of gamma radiation were found to be the near about 50% inhibition dose for callus survival in IBD-1 and MTU1010. The irradiated calli from both the varieties showed the survival rate near to 50% upon the 15 Gy treatment of gamma radiation indicating that the treatment of 15 Gy was better for mutagenic studies in rice. The results also exhibiting that the genus of the genotype is responsible for the callus sensitivity to gamma irradiation. The present study successfully demonstrates the use of in vitro mutagenesis and tissue culture to create genetic variations is the first step in any rice improvement programme.