Combining ability of TGMS lines for yield improvement in rice (Oryza sativa L.)

Combining ability analysis was conducted in 88 cross combinations made from four TGMS lines and 22 non-TGMS testers at Paddy Breeding Station, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India. Among the Thermosensitive Genic Male Sterile lines tested, GD 98049 and GD 99017 had superior per se performance with significant and desirable gca effects for yield contributing characters. The non-TGMS testers TKM 11, TKM 12 and TRY 2 were good general combiners coupled with high per se performance for major yield contributing characters. The hybrids, GD 99017 x Padmini, GD 98029 x TKM 11, GD 99017 x Padmini, GD 98049 x TRY2, GD 99017 x TKM 12, GD 98014 x TKM 11, GD 98049 x TKM 11 and GD 98029 x IR 10198-66-2 showed parallelism between sca and per se performance for most of the desirable traits. These crosses may be used for commercial exploitation of two line hybrid rice breeding. Combining ability revealed the pre-dominance of nonadditive gene action for most of the yield contributing characters which offered more scope for exploitation of hybrid vigour through heterosis breeding.