QTL mapping for Type II resistance to Fusarium head blight and spike architecture traits in bread wheat

Abstract In breeding for resistance to Fusarium head blight (FHB) there should be precise differentiation between QTL for resistance and those for spike architecture traits that indirectly affect disease. QTL mapping for FHB Type II resistance and spike architecture traits was carried out in a population of 80 RIL. Three QTL for FHB Type II resistance were identified respectively on chromosomes 2A, 4A and 6D, the last of which is reported here for the first time. The number of florets per spike and per spikelet was associated with FHB Type II resistance but there was not co-localization between QTL for these traits. However, QTL for number of spikelets per spike overlapped with those for FHB Type II resistance on chromosomes 2A and 6D. Spike architecture traits - notably, the number of florets per spike and per spikelet - should be considered in the design of breeding strategies to increase Type II resistance to FHB in bread wheat.

摘要：在抗赤霉病（Fusarium head blight, FHB）育种中，需精准区分抗性病数量性状位点（Quantitative Trait Locus, QTL）与间接影响病害发生的穗部构型性状相关位点。本研究以80个重组自交系（Recombinant Inbred Line, RIL）群体为材料，开展了赤霉病Ⅱ型抗性与穗部构型性状的QTL定位分析。研究共在2A、4A及6D染色体上分别定位到3个赤霉病Ⅱ型抗性QTL，其中6D染色体上的位点为本次研究首次报道。每穗小花数与每小穗小花数均与赤霉病Ⅱ型抗性存在关联，但这两个性状的QTL并未发生共定位。然而，每穗小穗数相关QTL与赤霉病Ⅱ型抗性QTL在2A和6D染色体上存在共定位现象。在培育普通小麦赤霉病Ⅱ型抗性品种的育种策略设计中，应将穗部构型性状——尤其是每穗小花数与每小穗小花数——纳入考量范畴。