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为了解小麦穗长性状的遗传特性,并将其应用于分子标记辅助育种,以大穗材料高麦1号/密小穗的292个植株的F2群体为材料,利用SSR标记对穗长进行了QTL定位分析。结果表明,选用500对SSR引物对高麦1号和密小穗两个亲本进行多态性检测,共获得180对在双亲间有多态性的引物,多态性引物检出率为36.0%。利用这180对引物进一步进行F2群体筛选,有96对引物在群体中表现出多态性,占多态性标记的53.3%。利用QTL_IciMapping软件构建出小麦染色体组的8个连锁群图谱,并将96对SSR引物定位到遗传连锁图谱上。图谱全长1 383.29cM,标记间的平均遗传距离15.37cM。平均每个连锁群有11.25个标记,含有标记最多的是4A和6B染色体,各有17个标记,其次是3A和7B染色体,含有9~14个标记,1B和5D染色体含有的标记最少,只有5~7个。共检测出7个与穗长相关的QTL位点,包括6个加性QTL和1个加性+显性QTL。7个QTL的加性效应值均为正值,单个QTL的贡献率为2.04%~15.26%。其中3A染色体上的QTL位点距离其最近标记只有0.58cM,为连锁最紧密的一个位点,并且其加性效应值最大,可解释表型变异的15.26%。因此,3A染色体上存在控制穗长的主效基因。
In order to understand the genetic characteristics of wheat ear length traits and to apply it to molecular marker-assisted breeding, the F2 population of 292 plants with large spike material Gaomai 1 / spikelet was used as material, and the spike length was determined by SSR markers QTL mapping analysis. The results showed that 500 pairs of SSR primers were used to detect the polymorphism of two parents of Gaoyue 1 and spikelet, and 180 pairs of polymorphic primers were obtained between parents. The detection rate of polymorphic primers was 36.0% . Using these 180 pairs of primers for further F2 population screening, 96 pairs of primers showed polymorphism in the population, accounting for 53.3% of the polymorphic markers. QTL_IciMapping software was used to construct eight linkage maps of wheat genome and 96 pairs of SSR primers were mapped to the genetic linkage map. The full-length map was 1 383.29cM with the average genetic distance between markers of 15.37cM. On average, there are 11.25 markers per linkage group, with the most abundant markers being 4A and 6B chromosomes, each with 17 markers, followed by 3A and 7B chromosomes, containing 9 to 14 markers, and 1B and 5D chromosomes containing the least markers 5 ~ 7. Seven QTLs related to spike length were detected, including 6 additive QTLs and 1 additive + dominant QTL. The additive effects of seven QTLs were positive, and the contribution rate of single QTL was 2.04% ~ 15.26%. Among them, the QTL locus on chromosome 3A was only 0.58cM closest to its nearest locus, which was the most closely linked locus and had the largest additive effect value, accounting for 15.26% of phenotypic variation. Therefore, chromosome 3A exists dominant gene controlling spike length.