Combining ability effects for fibre quality traits in first and ratoon crops of cotton interspecific hybrids (G. hirsutum×G. barbadense).

The combining ability effects were evaluated through line x tester analysis for the identification of best general combiners and specific combiners for fibre quality traits in 30 novel hybrids. The results revealed the presence of considerable genetic variation with respect to various fibre quality traits and significant differences for all the traits except elongation percentage and fibre fineness in both first and ratoon crops and indicated that the sca variances were higher than the gca variances for all the studied traits. The ratio of σ2 gca/σ2 sca was less than one for all the traits indicating the preponderance of dominant gene action, which plays an important role in the exploitation of heterosis through hybrid breeding. Parents AFRICAN I-2 and SVPR 4, KC 3 and SURABHI were found to be good combiners for fibre length and elongation percentage. The parent SUVIN was good combiner for fibre fineness. The sca effects revealed the best specific combinations viz., (i) the hybrids KC 3 x TCB 209, SVPR 4 x CCB 36 and SVPR 4 x TCB 209 for fibre length; (ii) AFRICAN I- 2 x DB 3 for uniformity ratio; (iii) COD 5-1-2 x DB 3, KC 3 x DB 3 and SURABHI x TCB 26 for fibre fineness. [ABSTRACT FROM AUTHOR]