The proportion of narrow fibers during early development predicts the diameter, fineness, and other quality traits of mature cotton fiber (Gossypium spp.)

Cotton fiber is an exceptionally long and strong outgrowth of the seed epidermis and the world’s most important textile material. To maintain the competitiveness of this renewable resource with synthetic fiber, the quality of the fiber typically produced by Gossypium hirsutum L. needs to be improved. For instance, fiber with lower fineness (or linear density) is preferred for the highest quality textiles. Based on prior research, we hypothesized that the proportion of narrow fibers early in development predicts the fineness of mature fiber. The hypothesis was supported by the currently reported analysis of 161 historical G. hirsutum accessions grown in the field along with two accessions of G. barbadense L., the species producing the highest quality fiber. Computer vision was used to estimate the proportion of narrow fibers three days after flowering, and mature fiber from the same field plots was analyzed by the High Volume Instrument (HVI) and the Automated Fiber Information System (AFIS). Linear regression analysis showed that a higher average proportion of young, narrow fibers was correlated with several improved qualities of mature fibers, including lower average fineness and diameter. Other analyses, including cooperative breeding trial data from multiple locations, demonstrated that there is genetic control on the narrow fiber proportion. The extent that environmental and other factors influence fiber shape proportions will need further exploration. We propose that consistently breeding for a higher proportion of narrow fibers in modern G. hirsutum cultivars would improve the quality of the G. hirsutum fiber crop. • Analyzing 166 Upland cotton accessions led to new insights on fiber quality control. • Computer vision allowed efficient, unbiased, classification of cotton fiber shape. • Variation in young fiber shape correlated with the fineness of mature cotton fiber. • The quality of mature cotton fiber is influenced by early fiber cell morphogenesis.