Abstract

                                Interspecific cotton hybrids were developed by crossing eight lines and seven testers and were tested in a line x tester mating design for nine quantitative characters. The parents TCH 1218, TCH MCU 13, TCH BS 279 and TCH 1715 among the lines and ICB 114, ICB 134, ICB CCB 1 and DB 1 among the testers contributed most of the promising hybrids exhibiting high heterotic vigour for most of the characters. Nine hybrids such as TCH 1716 x ICB 134, TCH 1716 x ICB 114, TCH 1716 x CCB 1, TCH 1716 x DB 1, TCH 1715 x CCB 6, TCH 1734 x CCB 6, BS 279 x DB 1, BS 279 x ICB 134, BS 279 x ICB 114 were judged to be promising for seed cotton yield based on their high heterosis percentage and per se performance. Among the 56 F 1 hybrids studied, TCH 1218 x ICB 114, TCH 1218 x CCB 1, TCH1218 x DB 1, MCU 13 x DB 1, TCH 1715 x CCB 1, BS 279 x ICB 137 and TCH 1716 x ICB 114 were superior for yield, yield component and fibre quality traits. These hybrid combinations could be exploited in heterosis breeding.

Key words : Cotton, heterobeltiosis, heterosis breeding, heterotic viguor, relative heterosis.