Table_1_A Calmodulin-Like Gene (GbCML7) for Fiber Strength and Yield Improvement Identified by Resequencing Core Accessions of a Pedigree in Gossypium barbadense.xlsx

Sea Island cotton (Gossypium barbadense) is world-renowned for its superior natural fiber. Although fiber strength is one of the most important fiber quality traits, genes contributing to fiber strength are poorly understood. Production of sea island cotton also is inextricably linked to improving its relatively low yield, thus enhancing the importance of joint improvement of both fiber quality and yield. We used genomic variation to uncover the genetic evidence of trait improvement resulting from pedigree breeding of Sea Island cotton. This pedigree was aimed at improving fiber strength and yielded an elite cultivar, XH35. Using a combination of genome-wide association study (GWAS) and selection screens, we detected 82 putative fiber-strength-related genes. Expression analysis confirmed a calmodulin-like gene, GbCML7, which enhanced fiber strength in a specific haplotype. This gene is a major-effect gene, which interacts with a minor-effect gene, GbTUA3, facilitating the enhancement of fiber strength in a synergistic fashion. Moreover, GbCML7 participates in the cooperative improvement of fiber strength, fiber length, and fiber uniformity, though a slight compromise exists between the first two of these traits and the latter. Importantly, GbCML7 is shown to boost yield in some backgrounds by increasing multiple yield components to varying degrees, especially boll number. Our work provides valuable genomic evidence and a key genetic factor for the joint improvement of fiber quality and yield in Sea Island cotton.

海岛棉（Gossypium barbadense）以其优异的天然纤维享誉全球。尽管纤维强度是最为关键的纤维品质性状之一，但目前对调控纤维强度的相关基因仍知之甚少。海岛棉的生产与改善其相对偏低的产量密不可分，因此同时改良纤维品质与产量的重要性愈发凸显。本研究利用基因组变异，解析了海岛棉系谱育种带来的性状改良的遗传证据。该育种系谱以改良纤维强度为目标，育成了优良品种XH35。本研究结合全基因组关联分析（genome-wide association study, GWAS）与选择筛选策略，共鉴定出82个推定的纤维强度相关基因。通过表达分析验证了一个钙调蛋白样基因GbCML7，该基因在特定单倍型下可增强纤维强度。该基因为主效基因，可与微效基因GbTUA3发生互作，通过协同作用提升纤维强度。此外，GbCML7参与纤维强度、纤维长度与纤维整齐度的协同改良，不过前两个性状与后者之间存在轻微的权衡关系。值得注意的是，GbCML7可通过不同程度地提升多个产量构成因子，特别是结铃数，在部分遗传背景下提高产量。本研究为海岛棉纤维品质与产量的协同改良提供了宝贵的基因组学证据与关键遗传因子。