Enhancements in cotton fiber length phenotyping and optimization of weighted gene co-expression network analysis through fiber elongation rate metrics

Cotton fiber length is a crucial attribute that significantly affects yarn production and fabric quality, making it a primary focus in cotton breeding efforts. Both current and previous studies have indicated a lack of correlation between fiber length and gene expression dynamics, underscoring the importance of phenotyping fiber elongation. traditional methods for measuring fiber length, however, tend to be impractical and labor-intensive, particularly for developing fibers that are fragile and prone to twisting. In this study, we present an innovative phenotyping method to measure the elongation of developing cotton fibers. Our key findings reveal a strong linear relationship between the total volume of fiber bundles and fiber length. This relationship allows for the straightforward estimation of the linear correlation coefficient from the final fiber length and the final volume of the fiber bundle within a boll. Upon measuring both the fiber bundle volume and fiber length, we discovered that their growth dynamics were well-represented by a logistic curve. Additionally, the expression dynamics of several newly identified genes demonstrated a significant positive correlation with the rate of fiber elongation. This research marks an important advancement in quantifying gene expression dynamics and fiber elongation. We believe that measuring the elongation of developing fibers will greatly accelerate the development of high-quality cotton varieties and enhance our understanding of plant developmental biology.