中文摘要：

目的 筛选与大白菜抗根肿病基因CRb紧密连锁的分子标记并检测所筛选出标记的通用性。【方法】以含有抗根肿病基因CRb的大白菜‘cRShinkiiDH’系为父本，以感病大白菜自交系‘07Q69’为母本杂交构建F：代作图群体。根据CRb基因连锁标记TCR01、TCR05和TCR09序列锁定的芸薹种A3染色体的目标序列，开发与凹6紧密连锁的分子标记，并进行精细定位。以芸薹种不同亚种为材料，验证CRb基因紧密连锁标记的通用性。【结果】获得了与CRb连锁的1个显性和4个共显性标记。TCR25和TCR74位于CRb的一侧，TCRl3、TCR42和TCR34位于另一侧。最近的2个侧翼标记TCR74和TCR13与卯6的连锁距离均为0．09cM。TCR74和TCR13的通用性检测结果表明，这2个标记在抗根肿病材料和感病材料间均具有高的多态性。【结论】将大白菜抗根肿病CRb基因定位在0．18cM的2个共显性标记之间，且这2个标记具有较高的通用性。

英文摘要：

[ Objective ] The objective of this study is to develop molecular markers closely linked to clubroot resistance （CR） gene CRb in Chinese cabbage, and to evaluate their utility in germplasms ofBrasisca rapa. [Method] A F2 mapping population was constructed with a cross between ＇CR Shinkii DH＇ line, a Chinese cabbage doubled haploid line containing CRb gene, and a clubroot susceptible Chinese cabbage inbred line ＇07Q69＇. Based on the target sequences showing homologous to the flanking markers TCR01, TCR05 and TCR09 linked to CRb on the chromosome A3 ofBrassica rapa, primer pairs were designed and markers closely linked to CRb were developed. Forty-two germplasms belonging to different subspecies of B. rapa were employed to evaluate the transferability of markers linked to CRb. [Result] Four co dominant and one dominant markers closely linked to CRb were developed and mapped. The markers TCR25 and TCR74 were located on one side of CRb, while TCR13, TCR42 and TCR34 were on the other side along with the previous markers TCR01 and TCR05. The CRb gene was flanked by two nearest markers TCR74 and TCR13 with the same genetic distance of 0.09 cM. The transferability evaluation of TCR74 and TCR13 showed that they possessed high polymorphism between clubroot resistant and susceptible sources. [ Conclusion] The CRb gene was mapped between two codominant flanking markers with genetic distance of 0.18 cM. The two nearest flanking markers showed high polymorphism and good versatility between resistant and susceptible sources ofB. rapa.