Li Yiqian, Si Zhanfeng, Wang Guoping, Shi Zhuolin, Chen Jinwen, Qi Guoan, Jin Shangkun, Han Zegang, Gao Wenhao, Tian Yue, Mao Yun, Fang Lei, Hu Yan, Chen Hong, Zhu Xiefei, Zhang Tianzhen
Zhejiang Provincial Key Laboratory of Crop Genetic Resources, the Advanced Seed Institute, Plant Precision Breeding Academy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.
Xinjiang Production and Construction Corps Seventh Division Agricultural Research Institute, Kuintun, China.
Mol Plant. 2023 Apr 3;16(4):662-677. doi: 10.1016/j.molp.2023.01.012. Epub 2023 Feb 2.
The excellent Upland cotton (Gossypium hirsutum) cultivars developed since 1949 have made a huge contribution to cotton production in China, the world's largest producer and consumer of cotton. However, the genetic and genomic basis for the improvements of these cotton cultivars remains largely unclear. In this study, we selected 16 Upland cotton cultivars with important historical status in Chinese cotton breeding and constructed a multiparent, advanced generation, intercross (MAGIC) population comprising 920 recombinant inbred lines. A genome-wide association study using the MAGIC population identified 54 genomic loci associated with lint yield and fiber quality. Of them, 25 (46.30%) pleiotropic genomic loci cause simultaneous changes of lint yield and/or fiber quality traits, revealing complex trade-offs and linkage drags in Upland cotton agronomic traits. Deep sequencing data of 11 introduced ancestor cultivars and publicly available resequencing datasets of 839 cultivars developed in China during the past 70 years were integrated to explore the historical distribution and origin of the elite or selected alleles. Interestingly, 85% of these elite alleles were selected and fixed from different American ancestors, consistent with cotton breeding practices in China. However, seven elite alleles of native origin that are responsible for Fusarium wilt resistance, early maturing, good-quality fiber, and other characteristics were not found in American ancestors but have greatly contributed to Chinese cotton breeding and wide cultivation. Taken together, these results provide a genetic basis for further improving cotton cultivars and reveal that the genetic composition of Chinese cotton cultivars is narrow and mainly derived from early introduced American varieties.
自1949年以来培育出的优良陆地棉（Gossypium hirsutum）品种为中国（全球最大的棉花生产国和消费国）的棉花生产做出了巨大贡献。然而，这些棉花品种改良的遗传和基因组基础在很大程度上仍不清楚。在本研究中，我们选择了在中国棉花育种中具有重要历史地位的16个陆地棉品种，并构建了一个由920个重组自交系组成的多亲本、高世代、互交（MAGIC）群体。利用该MAGIC群体进行全基因组关联研究，鉴定出54个与皮棉产量和纤维品质相关的基因组位点。其中，25个（46.30%）多效基因组位点导致皮棉产量和/或纤维品质性状同时发生变化，揭示了陆地棉农艺性状中复杂的权衡和连锁累赘。整合了11个导入祖先品种的深度测序数据和过去70年在中国培育的839个品种的公开重测序数据集，以探索优良或选择等位基因的历史分布和起源。有趣的是，这些优良等位基因中有85%是从不同的美国祖先中选择和固定下来的，这与中国的棉花育种实践一致。然而，七个具有本土起源的优良等位基因，它们负责抗枯萎病、早熟、优质纤维等特性，在美国祖先中未发现，但对中国棉花育种和广泛种植做出了巨大贡献。综上所述，这些结果为进一步改良棉花品种提供了遗传基础，并揭示了中国棉花品种的遗传组成狭窄，主要源自早期引入的美国品种。
