Combining Ability of Yield Components in Half Diallel Crosses of Cotton

Combining ability estimates were studied for seed cotton yield and its components in eight cotton cultivars (four Gossypium hirsutum and four G. barbadense) in half diallel crosses in 2000 and 2001 seasons, at the Gezira Research Station, Wad Medani, Sudan. Combining ability analysis revealed that both additive and non-additive types of gene action were important in the studied traits. The G. hirsutum parents,  Acala(93)H, Barac(67)B and Shambat-B, were best combiners for seed cotton yield, and the G. barbadense parents, Barakat-S and B-Pima, combined best for increased number of bolls and improved fiber quality. These results suggest the use of three-way crosses, modified backcross or recurrent selection to improve yield, yield components and fiber quality, The intraspecific crosses, gave low specific combining ability (SCA) effects, suggesting that, with few exceptions, parents within each species would not be useful in single cross combinations to produce progeny having high yields and improved yield components and fiber quality, Simple linear correlation coefficients revealed positive association of seed cotton yield with number of sympodia, lint index, boll weight and 100-seed weight suggesting that emphasis should be laid on these traits when selecting for increased yield