Unearthing hybridization opportunities for augmenting biomass yield and harvest index in rajmash (Phaseolus vulgaris L.)

In present study, 21 F₁ hybrids derived from crossing between seven female genotypes and three male testers following a line × tester mating design were evaluated for analyzing the component of genetic variation and heterosis of yield contributing traits. The components of variances due to gca and sca revealed the predominance of non-additive gene action for biomass and harvest index. The average better parent heterosis (BPH) and standard heterosis (SH) for Biomass yield (BY) was 43.71 and 114.67, respectively, and the average BPH and SH for the Harvest index (HI) was -13.04 and -20.45, respectively. The higher magnitude of the BPH and SH recorded for BY indicated that the scope for increasing the HI in Rajmash is limited and that further increases in productivity have to come mainly through enhanced BY. The parent RR- 21-01 and GR 1 were good general combiners for biomass, TRCR 3, TRCR 2, SKAU-R-19 and RKR 1033 for harvest index. Cross combinations IPR-277- 19 × HUR recorded positively significant sca effect for BY and IPR-277-19 × GR, TRCR 3 × GR 1, TRCR 2 × GR 1, IPR-205-19 × HUR, IPR-277-19 × GR 1, SKAU-R-19 × RKR 1033, RR-21-01 × HUR and RR-21-12 × GR 1 for HI. These results demonstrate that the selection of parents should not only be based on per se performance but also on combining ability and heterosis for achieving genetic improvement in Rajmash.