【目的】利用分子标记技术,构建甘薯遗传连锁图谱,并分析甘薯淀粉含量性状的QTL位点,为高淀粉含量甘薯种质资源利用及甘薯分子标记辅助育种提供理论和实践依据。【方法】以高淀粉含量品种万薯5号为母本、低淀粉含量品种商丘52-7为父本建立杂交群体,利用EST-SSR标记,采用"双假测交"策略和运用Join Map4.0软件,分别构建双亲遗传连锁图谱,并结合F1(2012、2013年)群体表型数据采用区间作图法对淀粉含量性状进行QTL检测。【结果】利用1 679对EST-SSR引物筛选出的1 045对多态性引物检测F1群体的标记基因型,获得了1 418个标记位点。分别对上述获得的父母本多态性标记进行遗传连锁分析,在LOD≥5.0情况下,分别构建父母本的连锁遗传图谱。采用642个标记的多态性位点构建母本连锁群74个,其中,215个标记位点位于连锁图谱上,占标记多态性位点总数的33.5%。每个连锁群上有2—11个标记位点,连锁群长度在0.6—129.4 cM,图谱总长为3 826.07 c M,标记间平均距离为17.80 c M。属于父本的776个标记位点构建了80个连锁群,共有252个标记位点构建在连锁图谱上,占标记总数的32.5%,每个连锁群上有2—24个标记位点,连锁群长度在2.0—156.8 c M,图谱总长为3 955.0 cM,标记间平均距离为15.7 c M。以F1杂交群体构建的遗传连锁图谱,结合2012年、2013年2个环境,利用QTL作图软件MapQTL5.0,采用区间作图法进行分析,共检测到17个与淀粉含量性状相关的QTL,贡献率在8.4%—40.5%。其中qWsc-1、qWsc-2、qWsc-3 3个QTL位于母本万薯5号连锁群上,且在2年环境中均可检测到;14个QTL位于父本商丘52-7连锁群上,qSsc-1、qSsc-2、qSsc-3、qSsc-4、qSsc-8、qSsc-10、qSsc-11、qSsc-12是在2个环境均检测到的QTL。qSsc-5、qSsc-6、qSsc-7、qSsc-9、qSsc-13、qSsc-14是只在1个环境检测到的QTL。标记GDAAS0603在双亲中和2个环境中均同时检测到,这些环境稳定QTL可�
To determine the genetic diversity and population structure of sweet potato accessions cultivated in China, and to establish the genetic relationships among their germplasm types, a representative collection of 240 accessions was analyzed using inter-simple sequence repeat(ISSR) markers. The mean genetic similarity coefficient, Nei's gene diversity, and shared allele distance of tested sweet potato accessions were 0.7302, 0.3167 and 0.2698, respectively. The 240 accessions could be divided into six subgroups and five subpopulations based on neighbor-joining(NJ) clustering and STRUCTURE results, and obvious genetic relationships among the tested sweet potato accessions were identified. The marker-based NJ clustering and population structure showed no distinct assignment pattern corresponding to flesh color or geographical ecotype of the tested sweet potato germplasm. Analysis of molecular variance(AMOVA) revealed small but significant difference between white and orange-fleshed sweet potato accessions. Small but significant difference were also observed among sweet potato accessions from the Southern summer-autumn sweet potato region, the Yellow River Basin spring and summer sweet potato region and the Yangtze River Basin summer sweet potato region. This study demonstrates that genetic diversity in the tested sweet potato germplasm collection in China is lower than that in some reported sweet potato germplasm collections from other regions. Pedigree investigations suggest that more diverse Chinese sweet potato varieties should be formed by broadening the selection scope of breeding parents and incorporating the introduced varieties into future breeding programs.
