新疆陆地棉骨干亲本及衍生品种数量性状的遗传基础和演化解析

Xinjiang is China's largest cotton producing areas, accounting for 63.7% of the production in our country. The development of cotton production in Xinjiang was largely benefit by genetic improvement and promotion of new varieties. In order to investigate the genetic basis of quantitative traits of the Xinjiang upland cotton developed from the introduction to the bred varieties, the founder parents and their derived cultivars, and to promote the sustainable development of cotton production in Xinjiang, the team collected a total of 185 germplasm resources of upland cotton including Xinjiang authorized “Xinluzao” and “Xinluzhong” varieties and their founder parents by the end of 2016, which formed an association mapping population. This research will focus on analyzing the population structure, population linkage disequilibrium and genetic diversity by whole genome re-sequencing; through the phenotypic evaluation in southern and Northern Xinjiang in multiple years, genome-wide association analysis and QTL mapping will be carried out on yield and fiber quality, early maturity and machine production traits, to analyze the genetic basis of Xinjiang upland cotton founder parents and their derivative cultivars; based on the four breeding periods, the evolution law of main characters of cotton in Xinjiang will be explored. By combining the excellent allelic variations of different traits, we will identify the germplasm resources carrying the excellent alleles to lay the foundation for constructing the multi parents’ MAGIC population of early maturity and mechanical harvest cotton by molecular design breeding.

新疆是我国最大的棉花产区，2016年产量占全国的67.3%，新疆棉花生产的发展在很大程度上得益于棉花品种的遗传改良和新品种的推广。为了解析新疆陆地棉从引种到自育品种、骨干亲本及衍生品种数量性状遗传基础，促进新疆棉花生产的可持续发展，课题组收集了截止2016年新疆审定的“新陆早”和“新陆中”系列陆地棉品种及其骨干亲本185份种质资源，构成关联分析群体。本研究拟对该群体进行全基因组重测序，分析其群体结构、群体连锁不平衡及遗传多样性；通过南北疆多年多点的表型鉴定，全基因组关联分析对产量、纤维品质、早熟性及机采等性状进行QTL定位，解析新疆陆地棉骨干亲本及衍生品种数量性状的遗传基础；针对新疆陆地棉四个育种时期，探析主要性状的演变规律。基于以上研究，综合不同性状的优异等位变异位点，鉴定携带优异等位基因位点的种质资源，为构建早熟机采的多亲本聚合杂交MAGIC群体分子设计育种奠定基础。

世界范围内种植和驯化了两种新的世界四倍体棉花，即陆地棉和海岛棉。陆地棉和海岛棉分别以产量和纤维品质而闻名。陆地棉和海岛棉的历史基因渗入前人已有研究;然而在我国单独选育陆地棉和海岛棉的优良品种时，其遗传效应和存在性尚不清楚。本研究收集了中国新疆地区159个陆地棉品种和70个半野生陆地棉品种以及30份海岛棉品种后，研究团队在6个环境中对9个纤维性状进行了种间导入试验、种内驯化分析和全基因组相关研究。在陆地棉中共鉴定出7个种间导入系和52个选择性扫描位点，以及在海岛棉中鉴定出了17个种间导入系和19个选择性扫描位点。9个纤维性状与导入的相关试验表明，导入位点有利于两种植物纤维性状的改良。此外，种内关联分析结果解决了种间导入事件（Gb_INT13），该事件有可能显著提高海岛棉的纤维产量。这项研究主要研究种间物种间的遗传导入和驯化景观，突出了种群间导入的遗传效应。了解我国种间导入和种内独立育种的遗传基础，有助于克服优良品种育种的瓶颈。.基于以上群体种质资源的收集和研究，构建陆地棉的微核心种质库。以503份陆地棉种质资源为研究材料，首先基于不同地理来源对棉花进行分组，采用产量品质性状标准化的数据进行欧式聚类分析，以50%的抽样比例结合极端材料构建初级核心种质库；然后利用CottonSNP63k芯片对原始种质进行扫描进一步对初级核心种质库筛选构建核心种质库；最后基于产量和品质相关优异等位基因聚合情况和系谱来源对核心种质库进一步浓缩，构建微核心种质库，包含31个优异的种质资源的微核心种质库。本研究所构建的微核心种质库具有广泛的变异范围，具有较好的遗传代表性，且聚合了优异等位变异，为棉花种质资源的创新及分子育种奠定基础。.项目共计发表文章6篇，其中1篇SCI,3篇ESCI，2篇核心期刊；基于分子设计育种选育新品系7份。研究成果大部分达到国际先进水平，较强应用前景和可持续研究价值。