Genetic effects of combining ability studies for yield and fibre quality traits in diallel crosses of upland cotton (Gossypium hirsutum L.)

The present study was carried out to investigate the diallel analysis in upland cotton (Gossypium hirsutum L.) by involving seven parents and their 42 cross combinations. All the characters were predominantly controlled by additive gene action except number of sympodial branches, single plant yield and bundle strength. Non additive gene action was controlled for the characters sympodial branches, single plant yield and bundle strength. The parent BW4-1 had superior per se performance for single plant yield, boll weight, lint index, number of bolls per plant, seed index, and micronaire followed by MCU 13 which had recorded high per se for single plant yield, lint index, seed index and number of sympodial branches. The parent TCH 1726 exhibited positive and significant gca effect for single plant yield, ginning percent, number of sympodial branches, boll weight and plant height. Based on high per se performance and high gca effect, the parent MCU 13 was considered as best general combiner as it had significantly greater values for single plant yield, number of sympodial branches, lint index and seed index. The hybrids KC 2 × TCH 1726 and TCH 1705 × MCU 3 had recorded high per se for single plant yield, number of bolls per plant and number of sympodial branches. Based on sca effects, KC 2 × TCH 1726 showed significant sca effects for single plant yield and number of sympodial branches. Key words: Cotton, Combining ability, gca, fibre quality traits, sca, single plant yield.