Heterosis and combining ability for biomass and harvest index in chickpea under a drought-prone, short-duration environment

Heterosis and combining ability studies were conducted on selected chickpea genotypes in order to (1) acquire an understanding of the predominant type of gene action governing biomass (BY) and harvest index (HI), (2) estimate the magnitude of heterosis, (3) estimate combining ability effects and (4) assess correlations between per se performance and general combining ability (GCA) of the parents under a drought-prone, rainfed short-duration environment (SDE) where BY is considered to be an important trait for enhancing chickpea productivity. The experimental material comprised 30 F₁s obtained by crossing ten adapted genotypes as females to three testers as males in a line × tester design. The GCA variances were significant and of a high magnitude, while specific combining ability (SCA) variances were non-significant, indicating the predominant role of additive gene action on BY and the HI. A large number of crosses showed positive mid-parent heterosis (MPH) and better-parent heterosis (BPH). The average MPH and BPH for BY was 22.36 and 12.65, respectively, and the average MPH and BPH for the HI was 2.22 and −0.92, respectively. The higher magnitude of the MPH and BPH recorded for BY indicated that the scope for increasing the HI in chickpea in a drought-prone, SDE is limited and that further increases in productivity have to come mainly through enhanced BY. The majority of the heterotic crosses involved poor × good combiners. This study demonstrates that in order to achieve greater progress in improving BY and the HI in chickpea, the selection of parents should be based on per se performance as well as combining ability and heterosis.