Mutation Induced Genetic Variability in Rice (Oryza sativa L.)

SEEDS of the Egyptian rice cultivar Sakha 105 were treated with three gamma radiation doses; 15, 20 and 25 Kr to study the effect of gamma irradiation doses in the process of mutation on the growth, yield and yield-related characters of sakha 105 rice cultivar as well as to induce genetic variability for selecting plants with desirable character. The effect of gamma -rays was observed in M-1 and M-2 generation for all the studied traits except panicle length in M1 and 1000-grain weight in both generations. The dose of 15 Kr recorded the highest mean value of heading date and plant height in both generation and number of panicles/plant in M-1 generation, this may be due to stimulatory effects of the low doses of gamma-rays which decrease with the increase of gamma irradiation The dose of 20 Kr recorded significantly higher fertility percentage and number of branches/panicle in M-2 generation and number of panicles/plant in M-1 generation. The dose of 25Kr produced the highest number of panicles/plant and number of spikelets/panicle in M-2 generation with in-significance difference with the control. While, it produced the lowest mean values for grain yield, number of filled grains/panicle, heading date and plant height in both generations. All the mutagenic treatments detected significantly lower grain yield than the un-treated plants in both generation. The measurements of variation were, in general, higher in the treated plants compared with the control. Such estimates were maximized in case of fertility percentage, number of filled grains/panicle and grain yield. Among all treatments, the dose of 25Kr gamma radiation detected the highest variation.