辣椒广谱主效抗疫病QTL精细定位

The most significant threat to pepper production is the phytophthora blight，breeding blight resistance new variety can solve this problem effectively, the key point of which is understanding the mechanism of R gene. However，fine mapping and characterization of late blight resistance candidate genes have not been reported. CM334 is considered as a broad-spectrum and high level late blight resistance variety in pepper, the resistance gene of which is mainly controlled by one major QTL（R2=47.65%）. We have constructed RIL and BC3F2 population， Our objective is to fine genetic mapping this QTL，identify rresistance candidate genes and develop high reliable molecular marker using QTL-seq and traditional QTL mapping technique. Our work will not only enable design of perfect markers for MAS in pepper ，But also help us understand molecular mechanisms of host resistance against pathogen in pepper.

辣椒疫病是辣椒生产上具有毁灭性的一种病害，选育抗病品种是克服辣椒疫病的有效途径，而基于R基因抗病机制的阐释是选育抗病品种的关键。然而目前还未见辣椒广谱抗疫病基因的精细定位及分离。CM334是国际上公认的抗疫病辣椒材料，具有广谱抗性，其抗性主要受一主效QTL控制（R2=47.65%）。前期课题组已利用CM334构建了RIL及BC3F2群体，本项目拟在前人研究基础上利用QTL-seq结合传统QTL定位技术精细定位该位点，获得广谱、主效抗病候选基因，并开发相应的可靠分子标记。该项目顺利完成不仅可以为辣椒抗疫病提供紧密连锁分子标记，用于辣椒分子标记辅助选择，也为研究辣椒和疫病互作分子机理奠定基础。

辣椒疫病是辣椒生产上具有毁灭性的一种病害，选育抗病品种是克服辣椒疫病的有效途径，而基于R基因抗病机制的阐释是选育抗病品种的关键。CM334是国际上公认的抗疫病辣椒材料，具有广谱抗性，其抗性主要受一主效QTL控制。课题组利用CM334和B12构建了F2群体，构建抗感病池，进行高通量测序，QTL-seq初步定位在第5染色体22.13-24.48MB区间。利用1000株F2群体进一步进行精细定位，最终将该QTL定位于标记NWSSR6584和NWSSR6923之间，与两个标记的遗传距离分别为0.9cM和1.7cM。该区域位于Zunla基因组5号染色体22763089bp- 23711326bp的区间内，大约为940kb。开发标记NWSSR6584，100份材料中只有2份表现型和基因型鉴定结果不一致，鉴定准确率为98%，可以用于育种实践。