Genetic Variability in Floral Traits of CMS Lines and Their Relationship with Outcrossing in Rice

Abstract

Thirteen cytoplasmic male sterile (CMS) lines were studied in Bangladesh for their genetic variability, correlation and path analysis. The rice plants were grown under medium high land condition of Bangladesh Rice Research Institute (BRRI), Gazipur, during Boro (November-May), 2009-10 season. Variability among the CMS lines was evaluated and relationship of outcrossing rate with floral traits was determined. The phenotypic coefficient of variation (PCV) values were greater than genotypic coefficient of variation (GCV), revealing a little influence of environment in trait expression. High heritability along with high genetic advance in percent of mean was observed in outcrossing rate, duration of floret opening and filament length. Outcrossing rate showed positive significant association with percent stigma exertion, angle of opened spikelet, stigma length and stigma breadth both at genotypic and phenotypic levels, though with percent panicle exertion and duration of floret opening at genotypic level only. The results suggested that higher outcrossing rate was contributed by the traits like angle of opened spikelet, percent stigma exertion, stigma length, stigma breadth and percent panicle exertion. Thus selection based on these traits for CMS lines would be effective for hybrid rice breeding program.