Lethal dose fixation and sensitivity of rice varieties to gamma radiation

The present study investigated the effects of gamma rays on crop phenotypes on two quality rice varieties viz., White Ponni and BPT 5204. The germination percentage and pollen fertility was found to be greatly affected by mutagenic treatments of gamma radiation in both the varieties which ultimately exhibited linear reduction with increase in dose or concentration of mutagens. The doses or concentrations can be determined by establishing the LD₅₀ value for the mutagen to be used. The expected LD₅₀ values of gamma radiation for White Ponni and BPT 5204 were 354.80 Gy and 288.40 Gy, respectively. Several plant traits like days to fifty per cent flowering, plant height, panicle length, leaf length, leaf breadth, number of productive tillers, number of grains per panicle, thousand grain weight and single plant yield was found to be greatly reduced due to mutagenic treatments. Based on the overall consideration of M₁ effects, the variety White Ponni was found to be highly sensitive to mutagens than BPT 5204.