Genetic Variability of Floral and Agronomic Characteristics that Influence Outcrossing Rate Percentage of Cytoplasmic Male Sterile Rice

Abstract

Developing high-yielding hybrid rice varieties is much needed to ensure food security to meet the requirement of the increasing population across the world. Cytoplasmic male genetic sterility system is a valuable technology for the exploitation of heterosis and production of high-yielding hybrid rice with better grain quality. Large-scale commercial exploitation of hybrid vigor in rice largely depends on the availability of good CMS (Cytoplasmic Male Sterile) lines. A total of eighteen traits of five CMS lines of rice were evaluated to study the variability and correlation between floral and other yield-contributing traits with outcrossing rate using Randomized Complete Block Design with three replications. High significant variation was observed among the genotypes for all the studied traits. High GCV (Genotypic Coefficient of Variance) and PCV (phenotypic Coefficient of Variance) coupled with high heritability and high genetic advance in percent of mean were observed for number of panicles per plant, filled grain, flag leaf breadth, stigma length and breadth, filament length and outcrossing rate which indicated the broad genetic base, less environmental influence, and these traits are under the control of additive gene action. character association and path analysis indicated that number of grains per panicle, filled grains per panicle, stigma length, and breadth possessed both positive significant correlation and positive direct effects on outcrossing rate therefore, selection for the traits mentioned above will certainly bring in the improvement of the outcrossing percentage of the lines, which in turn enhances the seed quantity of the hybrid.