Diallel Analysis of Fiber Traits for Extra-Long Staple Cotton Progeny

Demand for high-quality cotton (Gossypium hirsutum L.) in international markets has increased the demand for improved fiber quality in U.S.-grown cultivars. In an effort to meet this demand, cotton plant breeders seek alleles related to improved fiber quality. This study was conducted to evaluate fiber quality traits in a diallel analysis of eight cotton genotypes to determine genotypes with the greatest potential for improvement of fiber quality. Genotypes included four experimental extra-long staple (ELS) lines, A-106-8 ELS, B-147-21 ELS, B-182-39 ELS, and C-155-22 ELS, and four cultivars, 'Deltapine 491' (PI 618609), 'Deltapine 50' (PI 529566), 'Fiber-Max 832' (PI 603955; Constable et al., 2001), and 'Tamcot CAMD-E' (PI 529633; Bird, 1979). Parents and F-1 progeny were grown in replicated trials at the Texas AgriLife Research Farm near College Station, TX, in 2007 and 2008. Significant (p < 0.05) genotype x year (GxY) interactions were observed for all traits. Significant (p < 0.05) general combining ability (GCA) effects and specific combining ability (SCA) effects were found for most fiber quality traits measured as well as lint percent. Combining ability effects varied by year, which is reflected in significant general combining ability x year (GCAxY) and specific combining ability x year (SCAxY) interactions. Extra-long staple experimental lines from the Texas A&M University breeding program had the greatest potential for improving fiber length and strength as indicated by GCA.