Abstract
Cotton (Gossypium hirsutum L.) is a high value cash crop for the southern United States with an annual production of over 3.2 million t. For breeders to fully maximize yield potential and to improve fiber properties of new cotton cultivars, it is important to use representative test locations to evaluate genotype x environment (GxE) effects and trait repeatability. In this study, GxE analysis was performed on 31 upland cotton genotypes developed by the Texas A&M AgriLife Research Cotton Improvement Lab along with three commercial check cultivars. Seven distinct test locations across Texas representing major cotton growing regions were selected for the 2-yr study. All experimental plots were managed with standard field practices and were machine harvested to determine yield. Hand-harvested boll samples were ginned on a 10-saw laboratory gin and high volume instrument (HVI) fiber properties determined. Yield and lint percent along with HVI fiber bundle strength (strength) and upper-half mean length (UHML) were analyzed. Optimum test locations were identified for lint yield, lint percent, strength, and UHML. Combined correlation analysis of all traits indicated a high association between fiber yield and lint percent but highly negative association of yield traits and UHML. Repeatability of UHML and strength were 0.85 and 0.75, respectively, across all test locations in Texas over 2 yr suggesting a large genotypic component governing those traits.