小麦慢白粉病QTL对条锈病和叶锈病的兼抗性

聚合兼抗白粉病、条锈病和叶锈病的慢病性基因，是培育持久多抗小麦品种的重要措施。百农64和鲁麦21均为慢白粉病品种，分别含有4个和3个慢白粉病抗性QTL。将百农64与鲁麦21杂交，获得21个聚合2~5个慢白粉病抗性QTL的F₆株系，于2012-2013年度分别在四川郫县和甘肃天水进行条锈病田间抗性鉴定,在河北保定和河南周口进行叶锈病田间抗性鉴定。分析21个株系条锈和叶锈病的最大严重度和病程曲线下面积，检测单个QTL和QTL聚合体对条锈病和叶锈病的抗性效应。结果表明，QPm.caas-4DL、QPm.caas-6BS和QPm.caas-2BL对条锈病均有显著的抗性，分别解释表型变异的16.9%、14.1%和17.3%；QPm.caas-4DL对叶锈病也有显著抗性，可解释表型变异的35.3%；QPm.caas-1A/QPm.caas-4DL/ QPm.caas-2DL/QPm.caas-2BS/QPm.caas-2BL和QPm.caas-1A/QPm.caas-4DL/QPm.caas-2BS/QPm.caas-2BL聚合体对条锈病和叶锈病的抗性显著高于两亲本，它们均含有来自百农64的QPm.caas-4DL以及来自鲁麦21的QPm.caas-2BL和QPm.caas-2BS，表明这些QTL具有明显的兼抗性效应。在小麦抗病育种中，聚合慢病性QTL越多，慢病性越强，聚合4~5个慢病性QTL时，株系可达到高抗甚至接近免疫的水平，是选育持久抗性小麦品种的重要手段。

Resistance of Slow Mildewing Genes to Stripe Rust and Leaf Rust in Common Wheat

Pyramiding quantitative trait loci (QTLs) is an effective method to improve resistance to powdery mildew, stripe rust, and leaf rust in common wheat. We have developed 21 lines (F₆) carrying 2-5 slow mildewing QTLs by crossing slow powdery mildew cultivars Bainong 64 and Lumai 21 possessing four and three slow mildewing QTLs, respectively. These F₆ lines were evaluated in the field in Pianxian, Sichuan and Tianshui, Gansu for stripe rust resistance and in Baoding, Hebei and Zhoukou, Henan for leaf rust resistance during the 2012-2013 cropping season. According to the maximum disease severities (MDS) and the area under the disease progress curve (AUDPC), QTLs QPm.caas-4DL, QPm.caas-6BS and QPm.caas-2BL were highly resistant to stripe rust (P < 0.01), which explained 16.9%, 14.1%, and 17.3% of phenotypic variance, respectively. Locus QPm.caas-4DL also showed high resistance to leaf rust (P < 0.01) with phenotypic contribution of 35.3%. Lines that pyramided five (QPm.caas-1A/QPm.caas-4DL/ QPm.caas-2DL/QPm.caas-2BS/QPm.caas-2BL) and four (QPm.caas-1A/QPm.caas-4DL/QPm.caas-2BS/QPm.caas-2BL) QTLs exhibited higher resistance to both stripe and leaf rust compared with their parents. This result indicates that the combination of QPm.caas-4DL (from Bainong 64), QPm.caas-2BS and QPm.caas-2BL (Lumai 21) has a marked effect on improving adult resistance to powdery mildew, stripe rust and leaf rust, and the more QTLs are pyramided, the stronger slow disease resistance can be achieved. In breeding practice, the combination of 4-5 slow mildewing or rusting QTLs can result in durable resistance to multiple diseases.