Combining Ability Analysis and Association of Yield and Yield Components among Selected Rajmash (Phaseolus vulgaris L.) Lines

Background: Rajmash (Phaseolus vulgaris L.) is a significant leguminous crop known for its high protein content and dietary value. As global demand for nutritious food sources rises, enhancing the productivity and nutritional quality of Rajmash has become imperative. This research paper aims to investigate the combining ability and character associations in rajmash to facilitate the development of improved varieties with superior agronomic traits. Methods: An experiment was carried out in Rajmash using line × tester mating design to estimate the gca effect of parents and sca effect of 21 hybrids for yield and its traits using 7 lines and 3 testers. Hybrids along with ten parents were studied for combining ability and phenotypic correlations for seed yield and nine yield related traits. Result: The result indicated that the general combining ability (GCA) and specific combining ability (SCA) were significant for most characters indicating the importance of both additive and non-additive genetic components. This implies that a comprehensive understanding of both types of genetic effects is crucial for effective breeding programs. Among parent TRCR 3, SKAU-R-19, RR-21-01 and RKR 1033 were found to be good general combiners for seed yield per plant. This indicates their potential to consistently impart favorable traits to their progeny. The identification of such strong general combiners is valuable information for breeders aiming to enhance overall seed yield. The most promising specific combiners for seed yield were from crosses including SKAU-R-19 × RKR 1033, IPR-205-19 × HUR, RR-21-01 × RKR 1033, RR-21-12 × GR 1 and RR-21-01 × HUR. Significant desirable phenotypic correlations were observed between seed yield with days to flowering, days maturity, number of pods per plant, pod length and 100 seed weight these characters can act as indirect selection criteria in yield that could be used in rajmash breeding programs. The identification of strong general combiners, promising specific crosses and meaningful phenotypic correlations offers practical guidance for future breeding efforts, contributing to the development of improved varieties with enhanced yield potential and desirable agronomic traits.