Comparison of radiosensitivity of two rice (Oryza sativa L.) varieties to gamma rays and electron beam in M₁ generation

The present study was carried out to compare effect of gamma rays and electron beam on two rice varieties viz., ADT-37 and ADT(R) 45. Dried seeds of both the varieties were treated with gamma rays and electron beam with different doses viz., 100Gy, 200Gy, 300Gy, 400Gy, 500Gy for gamma rays and 200Gy, 300Gy, 400Gy, 500Gy, 600Gy for electron beam along with the control. The lethal dose was determined by probit analysis. LD₅₀ dose for ADT-37 and ADT(R) 45 was 300.03Gy and 300.00Gy for gamma rays and 286.45Gy and 275.05Gy for electron beam respectively. Results showed that germination, shoot length, root length, seedling height on 20^th day, pollen fertility and spikelet fertility in M₁ generation reduced steadily with the increasing doses of both mutagens. Based on the overall consideration of M₁ effects, the variety ADT(R) 45 was more sensitive to mutagens than ADT-37 and a prominent reduction was noticed in electron beam compared to gamma rays in both the varieties.