Sub‐Okra, Semi‐Smoothness, and Nectariless Effect on Cotton Lint Yield

Abstract

Combining all useful traits into a single genetic background does not always result in a genotype whose performance could be predicted by individual trait effects. Our objective was to evaluate the effects of three cotton (Gossypium hirsutum L.) traits, and their interactions with one another and environments. Sub‐okra leaf, semi‐smooth leaf, and nectariless were backcrossed into ‘DES 119’ from MD65‐11S. All eight combinations of the three traits were evaluated as BC4F4 and BC4F5 near isogenic populations in 1992 and 1993. They were grown at four locations near Stoneville, MS, in a randomized complete block design with six replications for yield and three for all other performance characteristics. No significant total yield response due to any trait was detected; however, sub‐okra leaf types produced significantly higher (35 kg ha−1 or 4%) first harvest yield than normal leaf types. Significant differences due to the main effects were detected for all other characteristics. Lint percentages for hairy and semi‐smooth types were 37.3 and 36.8, respectively. Fiber strengths for nectaried and nectariless isolines averaged 196 and 192 kN m kg‐1, respectively. Normal leaf had heavier bolls and seed, longer fiber, and lower fiber elongation than sub‐okra types. Seed of semi‐smooth isolines were heavier than those of hirsute cottons. Nectaried populations averaged larger bolls and seed, longer 2.5% span length, stronger fiber and higher elongation than that for nectariless populations. Interactions were smaller than the 1 to 4% differences detected for main effects. No major negative interactions among traits or with other environments were encountered. Incorporating these traits into one cultivar with similar genetic background to DES 119 should result in no major breeding problems.