小麦品种抗条锈基因的精细定位与抗病基因聚合育种

The first objective of this study is to identify one or two novel resistant gene(s) in common wheat for stripe rust by linkage analysis using SSR, AFLP, RGAP and STS, and to find three to four molecular markers closely linked to these resistant genes, with genetic distances less than 1.0 cM. The results will provide essential information for the cloning of resistant genes in wheat, and will facilitate pyramiding genes by marker assisted-selection (MAS) and deployment of resistant genes in the wheat growing region of Longnan, Gansu. Secondly, the cultivar Lantian 15 had two adult-plant resistance (APR) QTLs contributed by German cultivar Ibis, we make crosses between the cultivar and the homozygosis lines conferring all-stage resistant gene Yr5 derived from T.spelta album, to improve the probability of high and durable resistance to stripe rust in wheat. . Deployment of resistant cultivars is the most effective and economic strategy for controlling stripe rust. However, most of them confer race-specific resistance that is soon overcome by frequent genetic changes in the pathogen. The wheat-growing region, southeastern Gansu, can be divided into the over-summering and over-wintering areas where wheat can be grown from lowland valleys at 800 m to highland terrces at 2400 m and provide a "green bredge" for pathogen migration from late-maturing highland areas to early-sown wheat plants in lowlands. Therefore, this location is considered as a hotspot for stripe rust in China and lead to frequent changes of races. In addition, in the over-summering areas, the infected autumn-sown wheat provide initial inoculum for the major winter wheat regions of China. Finding novel sources of resistance to wheat stripe rust, and pyramiding major gene and APR QTLs in a genotype, which could be a desirable strategy to breed cultivars with all-stage and durable resistance to stripe rust, and also can be a more efficient strategy of stripe rust controlling in the wheat growing region of Longnan, Gansu.

本项目拟利用SSR、AFLP、RGAP和STS等分子标记研究小麦对条锈病的抗性，发掘抗条锈基因1-2个，找到与抗病基因连锁距离小于1.0 cM的分子标记3－4个，为抗病基因克隆、基因聚合和陇南小麦抗病基因布局奠定基础。同时对课题组育成的含主效抗条锈基因Yr5的稳定株系和含来自Ibis成株抗性QTL的兰天15号杂交，利用分子标记技术进行抗病基因聚合，创制具Yr5和成株抗性QTL聚合的优良新品系或育种中间材料，探索培育全生育期抗性与持久抗性相结合的小麦品种的途径与方法。. 选育抗病品种是防治小麦条锈病最经济有效的途径。但是条锈菌小种变异快，品种抗性频繁丧失，抗病育种常处于被动状态。发掘新的抗病基因，提高抗病基因的丰富度，以及主效基因与微效基因聚合，提高品种抗性的持久性，同时也实现了全生育期抗性与持久抗性的结合，是解决我国源头区域陇南小麦条锈小种易变和秋苗菌源向外传播问题的重要策略。

选择甘肃陇南地区种植的高抗条锈病的10个冬小麦品种，分别与高度感病品种辉县红杂交，构建了4个F2遗传群体、8个重组自交系群体。并对其中2个遗传群体进行苗期抗病性鉴定，利用SSR标记进行抗病基因作图分析。发现抗病品种白大头和武都白茧儿分别含有一个抗病基因，通过基因作图找到了与白大头抗性基因（位于1A染色体）紧密连锁的SSR分子标记Xgwm135和Xbarc209，与其连锁距离分别为1.4cM和3.7 cM；与武都白茧儿抗条锈性基因（位于4A染色体）紧密连锁的SSR标记Xbarc236和Xwmc468，连锁距离分别为19.5和31.2cM。.利用分别含有主效抗条锈病基因Yr5和Yr15的优良抗病株系与具成株抗病性的兰天15号（含成株抗性QTL QYr.caas-2BS.1 和QYr.caas-6BS）杂交、回交，对各分离世代单株进行田间抗病性鉴定结合分子标记检测，培育出一批含有抗病基因组合“Yr15 + QTL QYr.caas-2BS.1 + QYr.caas-6BS”或“Yr5 + QTL QYr.caas-2BS.1 + QYr.caas-6BS”且对田间混合条锈菌高抗至免疫、农艺性状较好的一批稳定株系。