Effect of Fiber Maturity on Bundle and Single-Fiber Strength of Upland Cotton

Maturity and strength are two of the physical properties that determine the quality and value of cotton (Gossypium hirsutum L.). Their relationship has been poorly understood due to technical difficulties of directly measuring maturity and strength from individual fibers. The narrow maturity and strength ranges of most upland cotton fibers have also impeded cotton scientists from performing statistical approaches. Therefore, we used genetic approaches to construct 168 new upland cotton materials covering broad ranges of maturity and strength and measured maturity ratio (MR) and strength-related properties from bundle and single fibers with reference methods. Comparisons of their properties showed that the MR values were significantly and positively correlated with single-fiber breaking force (cN) as well as bundle fiber strength (g tex(-1)) and elongation values. There were also correlations between the MR values and single-fiber strength (cN tex(-1)), although its r value was substantially affected by the linear density (tex) that normalized the breaking force (cN). The results showed that secondary cell wall development (maturation) is a major factor in determining bundle and single-fiber strength. These results will help cotton scientists understand the correlations between fiber maturity and strength and develop strategic plans to improve quality and yield of cotton fibers.