花生耐寒性特异种质遗传特性分析及其QTL定位

The injury of low temperature is one of the main limiting factors with developing of peanut industry. Breeding and planting of high yielding varieties with desirable cold tolerance are the ideal way of reducing the injury of low temperature. However, lack of specific germplasm in peanut with high cold tolerance, difficulties of identification of cold tolerance and lack of molecular markers are the main reasons that impede the breakthrough of breeding for cold tolerance in peanut. In this study, recombinant inbred line (RIL) population was constructed by using peanut varieties, which have different cold tolerance. This project aims to systematically identify the cold tolerance of the segregating population and analyze the genetic characteristics of cold tolerance. SSR, SNP and specific primers were designed based on the whole genome and transcriptome. The parents were analyzed with the designed primers, and RIL population was further analyzed.Based on identification of cold tolerance wilt in RIL population, identify the molecular markers of cold tolerance through the linkage analysis and construct the genetic linkage map. The differences of number, effect and position of cold tolerance related QTL among different peanut germplasms will be compared to obtain desirable germplasm lines and molecular markers with cold tolerance. The project will effectively provide theoretical and technical support in order to broaden the cold tolerant genetic basis, to improve the efficiency of cold tolerance genetic improvement, and has theoretical significance and broad application prospects.

低温寒害是限制花生产业发展的重要因子之一。培育和种植高产稳产耐寒性强的品种是降低遭受低温寒害的理想途径，然而高耐寒性花生特异种质的缺乏、耐寒性鉴定的困难及分子标记的缺乏，是限制耐寒性育种取得突破的主要原因。本项目拟以耐寒性差异显著的花生品种构建重组近交系（RIL）群体，系统鉴定分离群体的耐寒性，分析耐寒性的遗传特性。利用花生基因组和转录组数据设计引物，分析亲本获得多态性引物，进一步分析RIL群体多态性，通过连锁分析鉴定耐寒性的分子标记并构建遗传连锁图，比较不同花生种质所携带耐寒性QTL数量、效应和位置的差异，获得稳定耐寒性QTL标记。本项目的开展，将为有效地拓宽花生耐寒性育种的遗传基础、提高耐寒性遗传改良的效率提供理论和技术支撑，具有重要的理论意义和广阔的应用前景。

花生是我国分布极广的重要油料和经济作物，低温寒害是高纬度高海拔产区严重限制生产发展的关键逆境，其中对花生种子发芽期的危害最为普遍和严重。本项目针对深化花生品种高产稳产耐寒性遗传改良的迫切需要，旨在探讨花生耐寒性遗传特性及QTL定位，开发高效的耐寒性分子标记。通过对不同类型的花生耐寒性种质与敏感性种质"花育44号×DF12”和“远杂9102×徐州68-4”杂交构建的重组近交系（RIL）群体以及其他相关种质材料进行连续多年的耐寒性鉴定，获得稳定的耐寒性种质21份。对2个RIL群体进行耐寒性遗传特性分析，结果表明花生耐寒性受2-3对主基因+加性多基因控制。对“花育44号×DF12”构建的包含807个家系高世代RIL中随机选取200个RIL及其亲本进行全基因组重测序，构建了1张包含2494个bin标记的花生高密度遗传连锁图谱，分布在20个连锁群上。结合5个环境下RIL群体的耐寒性鉴定结果，获得与耐寒性相关的1个主效QTL，命名为qRGRB09，LOD为4.99-11.96，贡献率为10.85-24.07%，加性效应值为6.26-10.27。对所有环境的QTL区间取并集后该QTL位于46.74cM（C19P152409354)-61.75cM（C19P157324174），物理距离为6.01 Mb。利用KASP高通量基因分型，在主效QTLqRGRB09内部和侧翼开发10个KASP标记，以RIL群体中200个未参与重测序的家系材料为检测对象，结合被检测材料的耐寒性表型进行局部区间的QTL定位，最终将qRGRB09缩小在标记G22096与G22097之间，物理距离约为216kb的基因组区域，为后续进一步QTL精细定位和候选基因挖掘提供了重要的应用价值。