Genetic diversity for agronomic and fiber traits in day-neutral accessions derived from primitive cotton germplasm

Upland cotton (Gossypium hirsutumL) is an important crop that is cultivated in warm climates through-out the world. Agronomic performance and fiber quality must continually be improved if cotton is to maintain economic viability. Primitive ancestors of cotton contain diversity for trait improvement; however, many of these accessions have a short-day flowering response (photoperiodic) and are not readily useable in breeding programs. In this study, 114 day-neutral derived primitive germplasm lines were evaluated in field trials for two years. Agronomic and fiber trait data were collected and analyzed. Variance components, genotypic values, and genotypic correlations were calculated. Genotypic effects for all traits studied made significant contributions to the phenotypic variation indicating genetic diversity among these lines. The predicted genotypic values showed a wide range of variation for agronomic and fiber traits. Weak genotypic correlations were found between yield and 2.5% span length and fiber strength, two important fiber traits. Although these day-neutral derived accessions had lower lint percentage, they had improved fiber length, strength, micronaire, and comparable yields with two commercial cultivars. Thus, these day-neutral derived accessions are sources of genetic variation that when used in breeding programs offer the potential to improve important traits and expand genetic diversity.Contribution of the USDA-ARS in cooperation with the Mississippi Agric. and Forestry Exp. Stn. Mention of trademark, proprietary product, or vendor does not constitute a guarantee or warranty of the product by USDA, ARS and does not imply its approval to the exclusion of other products or vendors that may also be suitable.