Heterosis for seed cotton yield, yield contributing characters and fibre quality parameters intetraploid cotton (Gossypium hirsutum L.) and (Gossypium barbadense L.)

A line × tester crossing programme was taken up with seven lines and three testers with a view to identify the best heterotic crosses for seed cotton yield, yield attributing traits and fibre quality in cotton. A set of 21 (H × B) hybrids and one check hybrid DCH 32 were grown at Rasi seeds Research and Development Farm Attur. Analysis of variance showed significant differences amongst parents and hybrids for all the characters indicating presence of genetic variability. Heterosis was worked out over better parent and standard hybrid, DCH 32.Based on study of heterobeltiosis; it was found that number bolls per plant, boll weight were main contributors towards increase in heterotic effects for seed cotton yield per plant. The hybrid combination CG64× CG45SB (52.53 per cent), CG67 × CG45SB (45.57 per cent), CG62 × CG45SB (39.87 per cent), CG64 × CG45E (37.34 per cent) and CG67 × CG45E (35.44 per cent) were best heterotic crosses over standard check for seed cotton yield per plant. The crosses CG62 × CG45SB, CG 67 × CG45SB, CG64 × CG45SB, CG62 × CG45E and CG67 × CG45 Erecorded  highest standard heterosis for 2.5 per cent staple length  and the crosses CG62 × CG45SB, CG92 × CG45SB, CG67 × G45SB, CG67 × CG45E and CG62 × CG45E were  best for fibre strength. The crosses CG64 × CG45SB, CG67 × CG45SB, CG62 × CG45SB were best heterotic for the yield and fibre quality parameters and could be exploited.