Department of Plant Sciences, North Dakota State University, Fargo, ND, 58108, USA.
Department of Plant Pathology, Washington State University, Pullman, WA, 99164, USA.
Sci Rep. 2024 Feb 26;14(1):4614. doi: 10.1038/s41598-024-53710-z.
Breeding for resistance to Fusarium head blight (FHB) relies strongly on a limited number of larger-effect resistance QTL that have been mapped and associated with nearby markers. Smaller-effect (background) resistance QTL may also contribute moderate levels of resistance yet are mostly poorly characterized. Overall resistance of a genotype is determined by the combined action of both types of resistance QTL. This study aimed to identify well-adapted, advanced hard red winter (HRW) wheat breeding lines with useful background resistance QTL. A diallel trial consisting of 11 parents and 55 non-reciprocal F hybrids was tested for Type II FHB resistance in a replicated greenhouse experiment. Significant differences were detected among entries for disease severity (DS), general combining ability (GCA) and specific combining ability (SCA) with four parents being identified as the best general combiners with lowest DS. The ratio of GCA:SCA effects suggested that additive QTL effects were of primary importance. Overall, resistance QTL showed incomplete dominance, an excess of dominant alleles, and a greater contribution of positive effect genes. F of the six best F hybrids with the lowest DS were compared in a second greenhouse FHB trial to select possible transgressive segregates for continued evaluation and line development.
培育对镰刀菌穗腐病（FHB）的抗性强烈依赖于少数已被定位并与附近标记相关联的、效应较大的抗性 QTL。较小效应（背景）的抗性 QTL 也可能对中度抗性有一定贡献，但大多数都没有得到很好的描述。基因型的整体抗性由这两种类型的抗性 QTL 的共同作用决定。本研究旨在鉴定适应性强、具有有用背景抗性 QTL 的先进硬红冬（HRW）小麦育成系。在一个重复温室试验中，对由 11 个亲本和 55 个非互交 F 杂种组成的双列杂交试验进行了 II 型 FHB 抗性测试。在对疾病严重程度（DS）、一般配合力（GCA）和特殊配合力（SCA）进行检测时，发现各试验品系之间存在显著差异，其中有四个亲本被确定为具有最低 DS 的最佳一般组合体。GCA:SCA 效应的比值表明，加性 QTL 效应是主要的。总的来说，抗性 QTL 表现出不完全显性、显性等位基因过剩以及正效基因的贡献更大。在第二个温室 FHB 试验中，比较了六个 DS 最低的最佳 F 杂种 F1 的表现，以选择可能的超亲分离体进行进一步评估和系开发。
