大穗材料高麦1号/ 密小穗F2群体穗长性状的QTL初步定

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对在双亲问有多态性的引物,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1 383.29 cM,标记间的平均遗传距离15.37 cM.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0.58 cM,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.

Quantitative Trait Loci Mapping of Spike Length Using F2 Population of Gaomai 1/Mixiaosui in Wheat(Triticum aestivum L.)

Spike length is one of the important factors determining wheat yield. To understand the genetic characteristics of spike length characters in wheat,and to apply it in molecular marker assisted breeding,the trait of spike length was selected as the research object. At present,domestic and foreign researchers have used different groups to anchor the QTL location of spike related traits in wheat,but there are many differences in the results. In this study,the QTLs of spike length were analyzed using simple sequence repeat (SSR) markers with a population consisting of 292 F₂ lines derived from the cross between Gaomai 1 and Mixiaosui. Using DNA markers and QTL mapping,the QTLs of spike length were determined. Eight linkage groups were constructed by QTL-IciMapping software,and 96 pairs of SSR primers were located on the genetic linkage map. The full length of the map is 1383.29 cM,and the average genetic distance between the markers is 15.37 cM. On average,there are 11.25 markers in each linkage group.Seven QTL loci associated with spike length were detected,including six additive QTLs and one additive+dominant QTL. Seven QTL additive effect value were positive,with the contribution rate of 2.04% to 15.26%. The distance between the QTL locus on chromosome 3A and the nearest marker is only 0.58 cM,and the additive effect value of the QTL locus on chromosome 3A is the largest,which can explain 15.26% of the phenotypic variation. Therefore,chromosome 3A is likely to contain the main effect genes associated with spike length,and the follow-up study should focus on chromosome 3A.