Combining Ability, Heterosis and Gene Action for Grain Yield and Its Related Traits of Some WA-CMS with Tester Lines of Rice (Oryza sativa L.)

Abstract

An understanding the nature and relative extent of gene actions and combining ability is useful for a breeder to develop superior rice hybrids. In this association, an attempt was made to identify good general and specific combiners for selecting better parents and better cross combinations for developing high yielding and short duration rice hybrids. Four cytoplasmic male sterile lines viz., IR69625A, IR70368A, IR58025A and IR79575A were crossed with ten elite testers, 40 hybrids along with their fourteen parents were evaluated for grain yield and its related traits at the experimental farm of Rice Research and Training Center, Sakha, Kafr El-Sheikh, Egypt, during the rice-growing seasons of 2018 and 2019. The differences among genotypes, parents and crosses were highly significant for all studied traits. The specific combining ability (SCA) played the major role in determining inheritance traits, revealing that the largest part of the total genetic variability associated with most traits was a result of non-additive gene action. The parental line, IR58025A was demonstrated as a great general combiner for grain yield per plant and most of yield components and therefore could be utilized in future breeding programs to improve grain yield. HHZ12-SAL8-Y1-SAL1, HHZ5-Y7-Y2-SUB1 and HUA564 were seen as a good general combiner among testers for grain yield per plant and some studied traits. Four crosses, namely IR58025A / HHZ8-SAL9-DT2-Y2, IR70368A / WEED TOLERANT RICE1, IR70368A / HHZ12-SAL8-Y1-SAL1 and IR70368A / HHZ5-Y7-Y2-SUB1 exhibited significantly good specific combining ability effects for grain yield per plant. Hence, it can be seen that non-additive genetic effects are controlling the inheritance of the studied traits and indicated that selection for the traits inherited with this manner should be performed in the further generations.