Divergent Selection for Fiber Length and Bundle Strength and Correlated Responses in Cotton

Abstract

Cotton (Gossypium spp.) breeders must develop cultivars to meet the demand for longer, stronger, and more uniform fibers. In the current study, two cycles of divergent selection for fiber upper‐half mean length (UHML) and bundle strength (Str) were conducted within five diverse parental combinations selected based on their potential for the genetic improvement of fiber quality. Realized heritability estimates for UHML and Str were calculated for each cycle, and correlated responses among fiber properties and lint percent were measured as they responded to selection for UHML and Str. The results suggest that early‐generation selection for UHML and Str is an effective strategy for the genetic improvement of fiber quality at College Station, TX. Although UHML and Str were consistently negatively correlated with lint percent, the results demonstrate that sufficient variation for fiber quality exists within the Texas A&M AgriLife Research upland cotton germplasm to improve UHML and Str without a concomitant reduction in lint percent. A negative phenotypic correlation between UHML and fiber elongation at break was also observed and was independent of the association between Str and fiber elongation at break in multiple populations. These findings suggest that further investigation into the relationship between UHML and fiber elongation within the Texas A&M AgriLife Research germplasm is warranted.