【作者】 李慧；

【导师】 刘庆昌；

【作者基本信息】 中国农业大学 ， 作物遗传育种， 2014， 博士

【摘要】 1、从NCBI下载获得6130条甘薯EST序列,利用AutoSSR软件搜索出371条EST-SSR序列,利用Primer 3.0设计得到79对EST-SSR引物；从甘薯品种徐薯18全基因组的1215对SSR引物中随机抽取155对引物。利用两个甘薯作图群体的双亲和两个分离单株分别对SSR引物进行筛选,分别筛选出38对和40对多态性好的SSR引物,共计78对。两个甘薯作图群体分别是：以高产量、中等淀粉含量、感茎线虫病甘薯品种徐薯18为母本及低产量、高淀粉含量、抗茎线虫病甘薯品系徐781为父本杂交得到的由202个F。单株构成的分离群体；以高淀粉甘薯品种漯徐薯8号为母本及低淀粉甘薯品种郑薯20为父本杂交得到的由240个F1单株构成的分离群体。2、用筛选出的78对SSR引物,分别对两个甘薯作图群体进行扩增,所有引物均扩增出多态性好的条带。在徐薯18、徐781、漯徐薯8号和郑薯20中分别得到103、102、191和174个SSR标记,共计582个SSR标记。根据双假测交策略,利用JoinMap3.0作图软件,在本研究室构建图谱的基础上分别对徐薯18、徐781、漯徐薯8号和郑薯20的分子连锁图谱进行加密,分别新增55、46、126和140个SSR标记,使4张图谱均包含90个连锁群。徐薯18连锁图谱由1910个AFLP标记和192个SSR标记组成,总图距为10458 cM,标记间的平均距离为5.7 cM；徐781连锁图谱由1622个AFLP标记和176个SSR标记组成,总图距为9297 cM,标记间的平均距离为4.6 cM；漯徐薯8号连锁图谱由964个SRAP标记和126个SSR标记组成,总图距为9181 cM,标记间的平均距离为8.4 cM；郑薯20连锁图谱由826个SRAP标记和140个SSR标记组成,总图距为7798 cM,标记间的平均距离为8.1 cM。利用Duplex和Triplex标记对双亲图谱的连锁群进行同源性分析,徐薯18和徐781连锁图谱中分别得到14和15个同源连锁组；漯徐薯8号和郑薯20连锁图谱中分别得到12和11个同源连锁组。对父母本分子连锁图谱进行图谱间连锁群同源性分析,利用252个Double-simplex标记揭示出徐薯18图谱中51个连锁群与徐781图谱中45个连锁群之间具有同源连锁关系；利用156个Double-simplex标记揭示出漯徐薯8号图谱中48个连锁群与郑薯20图谱中47个连锁群之间具有同源连锁关系。3、利用MapQTL4.0软件的IM和MQM分析法,以及徐薯18和徐781杂交得到的由202个F1单株构成的分离群体,进行甘薯块根产量相关的QTL定位,共定位到9个主效QTL。徐薯18图谱上定位到4个稳定的QTL,解释表型变异的36.3%～59.3%,其中3个QTL表现正向效应；徐781图谱上定位到5个稳定的QTL,解释表型变异的37.0%-51.2%,其中1个表现正向效应。4、用SSR标记,构建了195个甘薯主栽品种的指纹图谱。用7对多态性高的SSR引物进行扩增,共得到49条多态性条带,利用NTsys进行遗传相似度分析,并利用MEGA4进行聚类分析,最终可将195个甘薯品种完全区分开。品种间遗传相似系数范围在0.3265～0.9796之间,地区内变异幅度最大的是福建,平均遗传距离为0.3900；地区内变异幅度最小的是安徽为0.1643。地区间的遗传距离最大的为广东与安徽,平均遗传距离为0.4002；地区间遗传距离最小的是江西与安徽为0.2211。更多还原

【Abstract】 1. A total of 6130 EST sequences were downloaded from the EST database of NCBI,371 EST-SSRs of which were screened using the software AutoSSR, and 79 SSR primer pairs were designed with Primer 3.0. A total of 1215 SSR primer pairs were derived from the genome sequencing of sweetpotato cv. Xushu 18,155 of which were sampled randomly. Screening for SSR primer pairs was performed on both parents and two progeny of two mapping populations, and 78 SSR primer pairs,38 and 40, respectively, produced good quality polymorphic markers. The first mapping population consists of 202 F1 individuals of a cross between Xushu 18, a cultivar susceptible to stem nematodes, with high yield and moderate starch content, and Xu 781, which is resistant to stem nematodes, has low yield and high starch content. The second mapping population consists of 240 F1 individuals derived from a cross between Luoxushu 8, a high starch content cultivar, and Zhengshu 20, a low starch content cultivar.2. The 78 SSR primer pairs were used for developing the polymorphic bands in two mapping populations. A total of 582 SSR markers were generated, which were 103,102,191 and 174 SSR markers in Xushu 18, Xu 781, Luoxushu 8 and Zhengshu 20, respectively. Using a two-way pseudo-testcross strategy and JoinMap 3.0 software, we developed genetic linkage maps of Xushu 18, Xu 781, Luoxushu 8 and Zhengshu 20 based on our previous study, and 55,46,126 and 140 SSR markers were added, respectively. The linkage map for Xushu 18 included 90 linkage groups with 1910 AFLP and 192 SSR markers and covered 10458 cM with an average marker distance of 5.7 cM; the map for Xu 781 contained 90 linkage groups with 1622 AFLP and 176 SSR markers and covered 9297 cM with an average marker distance of 4.6 cM; the map for Luoxushu 8 included 90 linkage groups with 964 SRAP and 126 SSR markers and covered 9181 cM with an average marker distance of 8.4 cM; the map for Zhengshu 20 contained 90 linkage groups with 826 SRAP and 140 SSR markers and covered 7798 cM with an average marker distance of 8.1 cM.Duplex and triplex markers were used to detect the homologous groups and 14 and 15 homologous groups were identified in Xushu 18 and Xu 781 maps, respectively, and 12 and 11 homologous groups were identified in Luoxushu 8 and Zhengshu 20 maps, respectively. Double-simplex markers were used to detect the homology of the corresponding linkage groups between both parent maps. In total,252 double-simplex markers revealed the corresponding relationships between 51 linkage groups of the Xushu 18 map and 45 of the Xu 781 map, and 156 double-simplex markers revealed the corresponding relationships between 48 linkage groups of the Luoxushu 8 map and 47 of the Zhengshu 20 map.3. Interval mapping (IM) and multiple quantitative trait locus (QTL) model (MQM) analysis were used to identify QTLs for storage root yield of sweetpotato in the population between Xushu 18 and Xu 781, a total of 9 major QTLs were located. Four QTLs were mapped on the Xushu 18 map, explaining 36.3% to 59.3% of the phenotypic variation, and three of them had a positive effect on the variation of yield. Five QTLs were detected on the Xu 781 map, explaining 37.0% to 51.2% of the variation, one of them had a positive effect on the variation.4. SSR fingerprinting of the 195 sweetpotato main varieties was constructed based on 7 primer pairs which generated 49 polymorphic bands. Each sweetpotato varieties could be clearly distinguished after genetic similarity analysis with NTsys software and cluster analysis with MEGA4 software. The genetic similarity ranged from 0.3265 to 0.9796, the maximum genetic variation existed within regions was in Fujian and the minimum genetic variation was in Anhui, the mean genetic distance was 0.3900 and 0.1643, respectively. The maximum genetic distance existed among regions was between Guangdong and Anhui, the minimum genetic distance was between Jiangxi and Anhui, the distance was 0.4002 and 0.2211, respectively.更多还原