牡丹花型等重要性状的QTLs定位研究

Tree peony, native to China, is an important horticultural crop due to its striking ornamental, medicinal and oil-used values. QTLs mapping of important traits, based on a high density genetic linkage map, has a remarkable value of theoretical research and potential application for marker-assisted selection breeding of tree peony. Based on phenotypic analysis combined with molecular marker detection method, we select the mapping population from a large number of F1 hybrid populations in this study. This population should have higher genetic polymorphism, significantly differentiating between relative characters and can representative the genetic characteristics of tree peony. More than 300 SSR molecular markers and more than 30,000 SNP markers will be developed by using tree peony c-DNA library and next-generation sequencing technique, respectively. Then these markers will be used in genotyping the mapping population and in constructing the first high density genetic linkagemap of tree peony. Important traits such as flower type, blooming period and growth potential in every individual plant of the mapping population will be investigated, and the genetic characteristics of them will be analyzed. Then these data will be combined with genetic map for QTL mapping, to detect the QTLs associated to phenotype of relative traits and some molecular markers tightly linked to these QTLs. This will lay the foundation for further the molecular marker assisted selection breeding of tree peony.

牡丹是我国特有的具有重要观赏价、药用与油用价值的作物，通过构建高密度遗传图谱对其重要性状的QTLs进行分析研究，对牡丹利用分子标记辅助选择技术培育新品种具有重要理论研究价值与生产应用潜力。本课题将利用表型性状对比与分子标记检测相结合的方法，从大量构建的F1代杂交群体中，筛选出遗传多态性高、相对性状差异显著，能真实代表牡丹遗传特点的分离群体作为构图群体；利用牡丹c-DNA文库与简化基因组测序法，分别开发300对以上的SSR分子标记与30,000以上的SNP分子标记，对作图群体进行标记检测，并利用遗传图谱构图分析软件构建首张牡丹高密度遗传图谱；同时调查分析F1代个体花型、花期及生长势等重要性状的遗传特点，结合遗传图谱开展QTL定位研究，最终获得与相关性状关联的QTL位点，为进一步利用分子标记辅助选择技术进行牡丹育种奠定基础。

牡丹（Paeonia Sect. Moutan）是我国特有的具有重要观赏、药用与油用价值的作物，通过构建高密度遗传图谱对其重要性状的QTLs进行分析研究，对牡丹利用分子标记辅助选择技术培育新品种具有重要理论研究价值与生产应用潜力。本研究把‘凤丹’牡丹 （Paeonia ostii ‘Fengdan’）和 ‘红乔’牡丹( P. suffruticosa ‘Hongqiao’)杂交，构建了F1群体为作图材料，采用简化基因组测序技术（Specific-locus amplified fragment sequencing，SLAF-seq）和简单重复序列（Simple sequence repeat, SSR）分子标记技术，构建了牡丹高密度遗传连锁图谱，并进一步开展了重要表型性状的数量性状位点（Quantitative trait loci, QTLs）定位研究。主要结果包括：.1）对作图群体亲本和195个F1子代个体进行简化基因组测序，获得了285,403,225 条序列（Reads），开发了309,198个SLAF标记，其中多态性标记有85,124个，对这些多态性标签进行基因型分析后，最终获得3518个有效SLAF标记和79对多态性SSR引物，进而通过连锁分析，构建了高密度遗传图谱。该遗传图谱共5个连锁群，包含有1261个标记，覆盖基因组总长为1061.94 cM，最大连锁群306.85cM，最小连锁群96.32 cM，标记间的平均图距为0.84 cM。.2）对牡丹枝、叶、花和果实4大类共27个数量性状，在作图群体中进行统计分析，发现这些性状表现为连续性变异，遗传变异系数在10.93%~78.56%之间，并呈现正态分布；利用MapQTL软件的restricted MQM （Multiple-QTL model）复合区间作图法，对27个数量性状进行了QTL分析，成功检测到与其中有20个性状相关的QTLs 49个；每个QTL可以解释表型变异的8.3 %~71.9 %。.综上所述，本研究构建了牡丹第一张高密度遗传图谱，并获得了一些控制重要性状的QTLs，为牡丹分子标记辅助选择育种技术发展奠定重要基础。