小麦品种曹选5号成株期抗条锈病基因的QTLs鉴定及精细作图

All-stage resistance is easily overcome by new races that can rapidly develop in the pathogen population. However, adult-plant resistance (APR) is usually race non-specific and durable. The development of wheat cultivars with adult-plant resistance (APR) has been given increasing emphasis in recent years because of its most effective method to control the disease. Wheat cultivar Caoxuan 5 was identified to have adult-plant (APR) resistance in 2007 to 2011. Based on the previous study on wheat cultivar Caoxuan 5, DNA bulked segregate analysis (BSA) was constructed and resistance gene analog polymorphism (RGAP) techniques were used to identify molecular markers linked to the resistance genes. To determine the chromosome location, RGAP markers were conducted using Chinese Spring nulli-tetrasomic lines. Subsequently, the simple sequence repeat (SSR), expressed sequence tags (EST) and diversity array technology (DArT) markers showing linkage with stripe rust resistance genes were used to genotype the entire population. The F3 lines were evaluated for genotype to stripe rust in field. Joint- and single-environment analysis by composite interval mapping identified quantitative trait loci (QTLs) in Caoxuan 5 for adult-plant resistance to stripe rust. To fine mapping of the adult-plant stage resistance major QTL, the mapping population was expansion and the recombinants of near QTLs were identified use molecular markers. Identification and fine mapping of adult-plant stage resistance genes to stripe rust in wheat cultivar Caoxuan 5 will to lay the foundations for the cloning of the gene, and will provide powerful and useful information for molecular marker assisted selection breeding, and will effectively promote the use of such resistance gene in breeding for race non-specific and durable resistance to stripe rust.

条锈菌毒性变异常使许多小麦全生育期抗性品种的抗病性丧失。然而，成株期抗病性具有非小种专化和持久抗病性的特点。培育和利用持久抗病品种成为防治小麦条锈病亟需解决的关键问题。所在实验室2007-2011年鉴定发现，小麦品种曹选5号具有成株期抗病性。本项目拟以此为基础，借助RGAP技术筛选亲本及抗感池；利用中国春缺四体系对抗条锈基因进行染色体定位；再用SSR、EST、DArT等标记技术对作图群体进行分析；获得与抗病基因紧密连锁的分子标记；对F3家系进行田间抗病性鉴定；利用复合区间作图法分析单环境和多环境成株期抗病的QTLs。通过扩大作图群体，不断采用分子标记来鉴定QTLs附近的重组体，对成株期抗病的主效QTL进行精细定位。小麦品种曹选5号成株期主效抗条锈病基因的鉴定及精细作图，不仅为克隆该基因奠定基础，而且为利用曹选5号开展小麦分子标记辅助育种提供科学依据，加速我国利用广谱和持久抗病育种步伐。

种植小麦抗病品种是防治小麦条锈病的有效途径。小麦抗条锈病的类型可以分为两类，即全生育期抗病性和成株期抗病性。全生育期抗病或者苗期性抗病性具有小种专化性，但其抗病性能在整个生育期表达。全生育期抗病基因随着时间的推移经常被新的流行小种所克服。成株抗病性（APR）具有非小种专化性，其抗病性在小麦的成株期表达，并且具有持久抗病性。利用全生育期抗病基因结合成株抗病基因作为新的抗源，是保护品种抗病性丧失和控制条锈病的持久策略。本项目将RGAP、SSR、EST等标记技术与BSA法构建抗感池的方法结合对小麦品种曹选5号抗条锈基因进行QTLs定位、QTLs分析，构建曹选5号成株期主效抗条锈病基因的QTL遗传图谱并进行精细作图,取得了以下研究进展。根据病害严重度（DS）和反应型（IT）数据，利用完备复合区间作图法（ICIM）定位了曹选5号3BS和6AL的两个QTL: QYrcx.nafu-3BS和QYrcx.nafu-6AL。这两个QTL与之前报道的抗病基因均不同；QYrcx.nafu-3BS和QYrcx.nafu-6AL是两个新的成株抗条锈基因。根据6AL上的EST序列开发了一个与QYrcx.nafu-6AL紧密连锁的STS标记。精细作图结果表明，QYrcx.nafu-3BS位于染色体物理图谱3B短臂片段3BS9-0.57-0.75上。