Combining ability and heterosis for yield and fiber quality properties in cotton (G. hirsutum L.) obtained by half diallel mating design

The objective of this study was to investigate the general combining ability (GCA) of parents and specific combining ability (SCA) of hybrids and also the genetic behavior for studied characteristics in the population obtained by 7×7 half diallel quantitative analysis method involving four MAR (Multi Adversity Resistance) and three commercial cotton (Gossypium hirsutum L.) varieties. The twenty one F1 and seven parents were planted as a randomized complete block design with four replications in 2004. The general combining ability (GCA) variance effects of the parents and the specific combining ability (SCA) variance effects of the hybrids and the gene effects were estimated by using the half diallel analysis method 2, model 1, described by Griffing. In the populations ginning percentage, fiber length, fiber fineness and fiber elongation properties were influenced by additive; seed cotton yield, fiber strength and fiber uniformity ratio were influenced by non-additive gene effects. Significant and positive heterosis values were observed except in fiber uniformity for seed cotton yield, fiber strength, fiber fineness, fiber elongation and ginning percentage respectively. It was determined that 'Sayar 314' for seed cotton yield and fiber length, 'Tamcot CD3H' for fiber uniformity ratio, 'Tamcot Sphinx' for fiber strength, 'Tamcot Luxor' for ginning percentage and fiber elongation, 'Tamcot HQ95' for fiber fineness were the best parent cotton cultivars and also having the best (GCA) general combining abilities. It was also determined that 'Maraş 92' x 'Tamcot HQ95' for fiber fineness, 'Stoneville 453' x 'Tamcot Sphinx' for seed cotton yield, 'Tamcot HQ95' x 'Tamcot Sphinx' for ginning percentage and fiber elongation, 'Maraş 92' x 'Sayar 314' for fiber length, 'Maraş 92' x 'Tamcot HQ95' and 'Tamcot CD3H' x 'Tamcot Sphinx' for fiber strength, 'Sayar 314' x 'Stoneville 453' for fiber uniformity ratio hybrid combinations were the most promising crosses with the highest specific combining ability