Abstract: Two bacterial blight(BB)resistance genes, Xa21 and Xa4,from IRBB24 were introduced into hybrid rice restorer line Mianhui 725, which is highly susceptible to BB by using hybridization and molecular marker-assisted selection technology. Four homologous restorer lines were obtained through molecular marker test for the R target genes and different parental genetic background analysis. Inoculation on the 4 lines and their hybrids were carried out with the specific Xanthomonas oryzae pv.oryzae strains, P1, P6(Philippine races) and seven representative strains of Chinese pathotype, CⅠ-CⅦ.The results indicated that all the 4 lines and their hybrids were highly resistant and showed broad resistance-spectrum to BB. The hybrids of G46A / R207-2 displayed good agronomic characters and high yield potentiality, and R207-2 was named as Shuhui 207.

Key words: bacterial blight, resistance, gene pyramiding, hybrid rice, restorer line, molecular marker-assisted selection, breeding

摘要： 通过常规回交育种结合分子标记辅助选择技术，已将来自IRBB24的2个抗白叶枯病基因, Xa21和Xa4, 聚合到感病的杂交稻恢复系绵恢７２５中。通过分子标记检测目标基因和亲本遗传背景差异分析快速获得了4个高抗白叶枯病的恢复系姊妹系R2071、R2072、R2073和R2074。采用与目标抗性基因相应的菲律宾菌系P1、P6 和7个中国病原型代表菌系（CⅠ~CⅦ）对4个姊妹系及其杂交组合进行田间接种。结果表明，这些姊妹系及所配制的杂交组合抗病性强、抗谱广，其中杂交组合G46A/R2072具有良好的产量潜力，将R2072定名为蜀恢207。

关键词: 白叶枯病, 抗性, 基因聚合, 杂交水稻, 恢复系, 分子标记辅助选择, 育种