| Cotton, Gossypium hirsutum L., is an important fiber crop. This study was undertaken to evaluate agronomic traits and conduct a genetic analysis of selected genotypes and F2-hybrids. Agronomic analysis included three genotypes 'Deltapine50' (DP50), 'Sure-Grow125' (SG125) and 'Sure-Grow501' (SG501) developed in the U.S. and six genotypes 'FiberMax832' (FM832), 'FiberMax963' (FM963), 'FiberMax975' (FM975), 'FiberMax989' (FM989), IF1000, and IF1005 developed in Australia by AgrEvo Cotton Seed International (ACSI), which differed in maturity. Genetic analysis involved the following parents FiberMax963, FiberMax989, 'Deltapine90' (DP90), Deltapine50, Sure-Grow501, 'PayMasterH1560' (PMH1560), 'Stoneville474' (ST474) and their F2-hybrids, which were produced following a half-diallel mating, scheme. The study was conducted from 1997 to 1999 at Mississippi State, MS. FM963 yielded more seed cotton, had a higher lint percentage and produced more bolls than all other genotypes. FM832 had significantly larger bolls than all other genotypes in 1997. There were no significant differences among the genotypes for boll size in 1998. Several F2-hybrids yielded higher than the parents. Dominance genetic effects controlled yield, yield components, micronaire, and span lengths, whereas, additive genetic effects controlled elongation and strength. General combining ability (GCA) effects for parents differed significantly for fiber traits. SG501 gave significant, positive GCA effects for all fiber traits studied except for span lengths. FM963 gave negative GCA effects for all fiber traits. Positive, significant specific combining ability (SCA) effects were smaller than GCA effects for fiber traits. Predicted genotypic values suggest that some crosses could be used as early generation hybrids, or that selection for a specific trait should be done in later generations. These results suggest that genotypes or F 2 cotton hybrids that combine beneficial traits of high yield (U.S.) genotypes with those of high fiber quality (ACSI) genotypes could be developed. |
