GENE ACTION OF SOME AGRONOMIC, YIELD AND QUALITY CHARACTERS IN AROMATIC RICE (ORYZA SATIVA L.) VARIETIES AND THEIR F1 HYBRIDS UNDER LOWLAND AND UPLAND ENVIRONMENTS
Gene action for twenty-one F1 hybrids along with their parents were evaluated in a experiment designed with randomized complete block design having three replications in two environments. Significant differences were observed among parents, hybrids and hybrids versus parents for most of the agronomic, yield and quality characters of hybrids in both environments. Genotype x environment interaction was also significant in most of the traits studied. Results based on combining ability tests showed that, gene action for yield and agronomic traits was dominant while gene action for quality traits was additive. Results reveal that specific combining ability (SCA) variances were higher than the general combining ability (GCA) variances under lowland and upland environments for all the characters studied, except number of productive tillers per plant, number of non- productive tillers per plant, length of panicle, percent filled grains per panicle and grain breadth. These data suggest that non-additive gene action is important. Estimates of GCA effects under both environments of this study revealed that lines Sugdasi, Bengalo and DR65 were the best general combiners for grain yield and tester, Pandan was the best potential source of desirable genes for yield and yield related traits. Heterosis breeding may be utilized to improve quality traits with dominant gene action.