以镇084和IRBB5为白叶枯病抗性基因的供体亲本，华占为受体亲本，通过杂交、二次回交，再进行一次复交，在分离世代利用分子标记辅助选择技术、白叶枯病菌接种鉴定和农艺性状筛选等措施，育成携带xa5、Xa7和xa5+Xa7基因的改良株系各1个，并对改良株系进行了抗白叶枯病鉴定。结果表明，分别携带xa5、Xa7基因的改良株系B1和B2对菌株PXO99均表现为高感，对其他４个菌株都表现为高抗或抗；携带xa5+Xa7基因的株系B3对PXO99表现为中感，对其他４个菌株都表现为高抗，抗性水平明显好于仅携带单基因的B1和B2。

Using rice lines Zheng 084 and IRBB5 as the donors of the bacterial blight resistance genes, two resistance genes （xa5 and Xa7） were introgressed into an indica restorer line Huazhan by crossing, backcrossing and multi-crossing. Based on marker-assisted selection method combined with evaluation of resistance and agronomic traits, one improved line carrying both xa5 and Xa7 was obtained, two improved strains carrying a single resistance gene xa5 or Xa7 were also obtained. The improved strains were identified for resistance to bacterial blight. The results showed that the improved lines B1（harboring xa5） and B2（harboring Xa7） were highly sensitive to the strain PXO99, and highly resistant or resistant to the other four strains; and the line B3 with both xa5 and Xa7 showed moderate sensitive to PXO99 and high resistance to the other four strains, which was superior in resistance to B1 and B2 with only a single gene.