Genetic Variability and Gene Action for Several Traits in F₄ and F₅ Population of Rice

This study estimated the genetic variability and gene action of several traits in the F₄ and F₅ rice populations to determine a trait for selection program. The trait of date to flowering and date to harvesting had narrow genetic variability, whereas trait productive tillers, number of fertile grain, and total grains had moderate to wide genetic variability. Genetic variability in trait number of fertile grain and total grains showed decreased in F₅ generation compare to the F₄ generation, whereas trait productive tillers, date to flowering, and date to harvesting showed an increase. Additive gene action with duplicate and complementary epistasis was found in all traits, except for trait productive tillers only showed additive gene action with duplicate epistasis. Kurtosis less than 3 was found in all traits which indicate many genes control the traits. The number of fertile grain trait showed wide genetic variability which decreased in F₅ generation compare to the F₄ generation, and there is an additive gene action with duplicate epistasis. It indicates selection will be effective with the trait of number of fertile grain.