Abstract
The present research was carried out so as to estimate general combining ability (GCA) which is due to additive genes action, whereas specific combining ability (SCA) is due to dominant and epistatic gene effects of five inbred parents and heterotic effects of 10 F1 hybrids, developed from half-diallel crosses. Mean squares due to GCA and SCA variance was highly significant for all the characters studied; number of bolls per plant, boll weight, seed cotton yield per plant, seed index and ginning outturn. The variance due to GCA and SCA for mean squares was highly significant, which suggested that additive and non-additive gene action is involved for controlling all the characters. The SCA variance were higher than GCA which indicated the preponderance of dominance of genes for number of bolls per plant, boll weight and seed cotton yield per plant, whilst GCA variance were higher than SCA which manifested the predominance of additive gene for seed index and GOT. Among the parents MNH-886, CIM-506 and CRIS-134 proven best general combiner for all the traits except seed index. It further suggested that these parents can be exploited in crop improvement to maintain the traits studied. As per hybrid combinations MNH-886 X CIM-506, CRIS-134 X MNH-886 and BH-36 X MNH-886 were specific combiners for all the traits studied except GOT. Consequently these can be used for exploitation in hybrid crop development program.
