LEGACY STUDY OF COTTON SEED TRAITS IN UPLAND COTTON USING GRIFFING'S COMBINING ABILITY MODEL

Combining ability was studied for identification of potential cultivars and hybrids, and the nature of gene action involved for inheritance of cottonseed traits and oil content % in a 6x6 diallel cross in upland cotton (Gossypium hirsutum L.) during 2003-2005. Analysis of variance revealed highly significant (p <= 0.01) differences among the genotypes for all the traits. Combining ability studies showed that the mean squares due to general combining ability (GCA) and specific combining ability (SCA) were mostly significant in F-1 and F-2 generations. Genetic components of variances due to GCA and SCA revealed that most of the traits were controlled by additive type of gene action in both generations because of greater GCA variances. However, seeds per boll and cottonseed oil % in F1 generation gained preponderance of SCA variances having non-additive type of gene action. Cultivar CIM-1100 was found as leading general combiner in combination with other cultivars BH-36 and CIM-240, FH-682 and CRIS-9, and their hybrids (CIM-1100 x BH-36, CIM-240 x CIM-1100, FH-682 x BH-36, CIM-1100 x FH-682 & CIM-1100 x CRIS-9) showed prominent SCA and renowned mean performance for seeds per boll, seed index and cottonseed oil content %. Therefore, involvement of CIM-1100 in most of the hybrids resulted in the synthesis of superior genotypes for all the traits.