Abstract: Fusarium head blight (FHB) is one of major diseases in wheat. Stacking different quantitative trait loci (QTL) via marker-assisted selection is an effective and environmentally friendly approach to control the disease and to reduce the toxin content in grains. The QTL for scab resistance have been identified throughout the wheat genome, however, except for a few QTL, such as Fhb1 and Fhb2, most of the QTL lack efficient diagnostic markers. simple sequence repeat (SSR) marker is rich in polymorphism, which can differentiate different alleles in a natural population, and can be easily used in marker assisted breeding. Based on this, a panel of 386 SSR markers associated with scab resistance were collected from published literatures, which were then used to construct consistent genomewide QTL maps for scab resistance. Variation of copy numbers for these associated markers were analyzed, and SSR markers of single copy were selected. These single-copy markers were then used to genotype a natural population consisting of 156 varieties, and association of single marker genotypes with phenotypic data collected in field and greenhouse environments for three seasons each were performed. The allelic variations and their genetic effects of those single-copy SSR markers significantly associated with scab resistance were analyzed. The results showed that a total of eight single-copy SSR markers were significantly correlated with the phenotype in at least two seasons (P<0.05), involving chromosomes 2D, 2B, 3B, 5A, 5B, 6A, 6D and 7A, and five single-copy markers had effective alleles. Chinese wheat landraces and Japanese varieties had more favorable (resistant) alleles, and the more favorable alleles the varieties had, the better the resistance to scab was observed. These QTL loci and their linked single-copy SSR markers could be used in wheat breeding to improve the level of scab resistance and breeding efficiency.

Key words: wheat scab resistance, single-copy markers, association analysis, allelic variation, genetic effects

摘要： 赤霉病是小麦主要的流行病害之一。借助标记辅助选择将不同数量性状基因座（quantitative trait loci，QTL）聚合是防治赤霉病有效且环保的方法，可以从源头上控制赤霉病并降低籽粒中毒素含量。抗赤霉病QTL在小麦全基因组均有分布，但除了Fhb1、Fhb2等少数位点有比较可靠的鉴别标记，绝大部分位点缺乏有效的位点特异性鉴别标记。简单重复序列（simple sequence repeat，SSR）标记多态性丰富，可以区分自然群体中不同等位变异，方便用于标记辅助育种。基于此，搜集了不同文献中报道的与赤霉病关联的SSR标记386个，并用这些标记构建全基因组赤霉病抗性QTL一致性图谱，接着对这些关联标记进行拷贝数分析，进而选择位点内的单拷贝SSR标记，将这些单拷贝标记在156个品种组成的自然群体中进行扩增，并与三季大田和三季温室环境下赤霉病抗性进行关联，筛选与赤霉病抗性关联的单拷贝SSR标记，明确这些标记在自然群体中的有效等位变异和效应。结果表明，共8个单拷贝SSR标记至少在两季试验中与表型显著关联(P<0.05)，涉及2B、2D、3B、5A、5B、6A、6D、7A染色体，有5个单拷贝标记位点存在有效等位变异。中国地方品种和日本品种携带更多的有利变异，且有利等位变异数目越多的品种赤霉病抗性越好。研究分析的QTL位点及其关联的单拷贝SSR标记可用于赤霉病抗病育种，有利于提高品种赤霉病抗性水平和育种效率。

关键词: 小麦赤霉病抗性, 单拷贝SSR标记, 关联分析, 等位变异, 效应解析