中文摘要：

在前期利用抗病品种Acc8558和感病品种H359杂交的重组自交系群体对水稻细条病抗性QTL初步定位的基础上，对效应最大的抗性QTL qBlsr5a进行了验证和更精确定位．以Acc8558为供体亲本、H359为受体亲本，通过连续4次回交和2次自交，结合表型选择和标记辅助选择，对qBlsr5a建立了受体亲本的近等基因系．进一步将该近等基因系与H359杂交，建立次级作图群体（F2：3），对qBlsr5a进行更精确定位．结果表明，qBlsr5a真实存在，位于第5染色体短臂上SSR标记RM7029与RM413之间，表现为加性效应，能够解释26．53％的表型方差．

英文摘要：

On the basis of a previous study on the primary mapping of QTLs underlying resistance to bacterial leaf steak in rice using a population of recombinant inbred lines derived from a cross between a resistant variety Acc8558 and a susceptive variety H359, verification and more precise mapping of the QTL qBlsr5a that showed the largest effect was conducted. With Acc8558 as the donor parent and H359 as the acceptor parent, an isogenic line of the acceptor parent for qBlsr5a was created by four successive backcrosses and two selfings, combined with phenotypie selection and marker-assisted selection. The isogenic line was further crossed with H359 to establish a secondary mapping population （F2：3 ）, which was used for more precise mapping of qBlsr5a. The result indicated that qBlsrSa is true, located between the SSR markers RM7029 and RM413 on the short arm of chromosome 5, exhibiting additive effect, and explaining 26.53% of the phenotypic variance.