Effect of Fruiting Position on Cotton (Gossypium hirsutum) Fiber Fineness and Maturity

Cotton fiber utility in textiles is determined in part by its micronaire value. This quantitative trait is dependent on the sample fiber’s fineness and maturity, each having specific effects on yarn quality. For example, fiber fineness imposes limits on spin count and elongation, while fiber maturity imparts strength and dye retention. Therefore, the goal of this experiment is to define how cotton fibers, from different fruiting positions, vary for these traits individually. Previous studies have examined the variation in micronaire, as well as yield, and discovered significant variation between fruiting positions. By box mapping five genotypes from two diverse environments, this research seeks to estimate the genotypic and environmental variation present in fiber fineness and fiber maturity. Determining the value for these two traits has been problematic, however, new methods of quantifying fiber fineness and maturity have developed outside of cross-sectional image analysis, sodium hydroxide swelling, Advanced Fiber Information System, and High Volume Instrumentation. One new method, the CottonScope, uses polarized light microscopy to view 20,000 snippets of fibers suspended in solution. Software quickly analyzes the images by length, cell wall thickness, and fiber perimeter. From these measurements, the CottonScope is able to quantify the distribution of observations in a sample’s fineness and maturity. The utility of this new method in terms of breeding objectives has yet to be explored.  The information gained from this study aims to assist breeders in increasing uniformity of a crop’s quality through defining the relationship of fruiting position to fiber fineness and maturity.