中文摘要：

【目的】挖掘和分析芸薹种抗根肿病基因及基因间的互作关系,为芸薹种抗根肿病育种提供理论依据。【方法】以大白菜自交系‘BJN’为母本,芜菁自交系‘Siloga’为父本进行杂交获得F1。F1单株自交获得由140个单株构成的F2群体,用于遗传图谱构建。95个F2单株及其F3家系用于抗根肿病（CR）性状的QTL定位和上位性互作分析。利用1 214个分子标记和前人开发的与7个CR连锁的22个标记进行亲本间多态性筛选。根据作图群体的多态性标记基因型,采用JoinMap 4.0作图软件构建遗传连锁图谱。以采自甘蓝型油菜栽培地的根肿菌对2个亲本及其95个F2：3家系进行根肿病抗性鉴定。根据F3植株的发病等级,计算F2单株的平均发病指数（DI）。利用Windows QTL Cartographer 2.5软件,采用复合区间作图法检测抗根肿病QTL。利用基于混合线型模型的QTL Network 2.0软件进行互作关系分析。SPSS 18.0.0软件用于分析F2群体中QTL连锁标记的基因型与其相应个体平均DI值间的相关性。双因素方差分析方法分析QTL连锁标记的交互作用。通过单因素方差分析,采用最小显著差异法和q检验（SNK）多重比较QTL紧密连锁标记（sau_um026和BrID90197）组合成的9种基因型在根肿病抗性上的差异。【结果】抗病性鉴定表明‘Siloga’对根肿菌表现为抗病,而‘BJN’表现为感病。F2群体中根肿病发病指数呈偏正态分布,表明根肿病抗性表现为由主效基因存在的多基因控制的数量性状。利用检测到的261个多态性标记构建出一个包含222个标记和10条连锁群的芸薹种遗传图谱。该图谱总长度为1 152.6 cM,定位了与3个CR连锁的5个标记,覆盖了大白菜参考基因组的88.6%。通过QTL定位共检测到源于‘Siloga’的2个QTL位点,分别位于A3连锁群的主效QTL（qPbBa3.1）和A8连锁群的微效QTL（qPbBa8.1）。qPbBa3.1和qPbBa8.1的贡献率分别为19.02%和7.82%。qPbB

英文摘要：

[Objective] This study was focused on the identification of quantitative trait loci （QTL） and epistatic interaction for clubroot resistance in Brassica rapa. [Method] A Chinese cabbage inbred line ＇BJN＇ （B. rapa ssp. pekinensis） as a maternal parent was cross-pollinated with a turnip inbred line ＇Siloga＇ （B. rapa ssp. rapifera） to obtain Ft seeds. An Fz population consisted of 140 individuals from one bud self-pollinated F1 plant was employed to construct genetic map. Ninety five F2 individuals and their F3 families were used for QTL mapping and epistatic analysis for clubroot resistance （CR）. In addition to 22 markers linked to 7 previously mapped CR genes, 1214 public molecular markers developed in B. rapa were scanned for polymorphism between two parents. JoinMap 4.0 was employed to construct the genetic linkage map. Clubroot resistance test was carried out against the two parental lines and F2：3 families with the field isolates of Plasmodiophora brassicae collected from Brassica napus milpa in Anhui＇s Huangshan. The disease index （DI） was evaluated as the mean DI for each F2 individual based on the results of F3 seedlings. QTL detection was performed using the composite interval mapping function provided by Windows QTL Cartographer 2.5. QTL Network 2.0 was used to identify putative epistatic loci based on a mixed linear model. The association between the genotypes of CR QTL linked markers in an F2 population and the mean DI value of each F2 plant was analyzed with SPSS 18.0.0. Two-way analysis of variance （ANOVA） was used to study the interaction effects between CR QTL linked markers. The differences among the nine genotypic groups classified by two QTL linked markers （sau_um026 and BrlD90197） were assessed by multiple comparisons with least significant difference test and Student-Newman-Keuls test. [Result] Clubroot resistance test showed that ＇Siloga＇ was resistant to clubroot disease, while ＇BJN＇ was susceptible. The skewed normal distribution of the disease