Inheritance of cotton fiber length and distribution

Fiber quality data from five upland cotton (Gossypium hirsutum L.) genotypes, which were grown at College Station, TX during 2001 and 2002, were subjected to diallel and generation means analyses to determine the potential for improvement of fiber length and to determine the inheritance of length distribution data. Four near-long staple (NLS) upland cotton genotypes and one short-staple genotype were crossed in all combinations, excluding reciprocals. Estimates of general (GCA) and specific combining ability (SCA) for fiber length based on GriffingâÂÂs diallel Model I, Method 4 were calculated for high volume instrumentation (HVI) upper-half mean (UHM) fiber length and advance fiber information system (AFIS) mean fiber length by weight (FLw), mean fiber length by number (FLn), upper quartile length by weight (Uqlw), fiber length distribution cross entropy (using 3 different standard or check distributions - CEA, CEB, and CEC), fiber length distribution kurtosis (FLwKurt), and fiber length distribution skewness (FLwSkew) for FLw. Across environments, GCA effects were significant for fiber length measurements of UHM, FLw, FLn, Uqlw, and SFCw and distribution measurements of CEA, CEB, FLwKurt, and FLwSkew. On the basis of GCA effects, TAM 94L-25 was the best parent to be used in a cross to improve upland fiber length, while Acala 1517-99 was the parent of choice to improve distribution among the 4 parents tested. The inheritance of AFIS fiber length measurements and distribution data was estimated using parents, F1, F2, and backcross generations. The magnitude and significance of the estimates for non-allelic effects in the parental combinations suggest that epistatic gene effects are present and important in the basic mechanism of AFIS fiber length and length distribution inheritance for the populations studied. Gene effects and variances for all AFIS fiber length and distribution data measurements were inherited differently in different environments and specific parental combination, suggesting environmentally specific mechanisms. Developing genotypes with enhanced fiber length and an optimal fiber length distribution should be a priority to improve spinning performance and product quality of U.S. upland cotton