【摘要】 以感病杂交稻恢复系明恢 6 3的成熟胚为外植体 ,利用离体筛选技术获得了抗水稻白叶枯病细胞突变体HX 3。连续 8年以我国长江流域白叶枯病代表菌株浙 173(Ⅳ型 )对HX 3的R1 到R9代进行抗性鉴定 ,HX 3的抗病性可以稳定遗传。抗性遗传分析表明HX 3的抗性由 1对显性核基因控制。 1999～ 2 0 0 0年连续两年利用我国、菲律宾和日本的 32个水稻白叶枯病菌株 ,测定HX 3及IRBB1等 13个具不同显性抗病基因的近等基因系抗性 ,HX 3抗谱广 ,且与已知显性抗病基因的抗谱不同。在此基础上 ,以抗白叶枯病近等基因系IRBB4、IRBB7、CBB12和IRBB2 1和HX 3杂交 ,进行等位性分析 ,4个杂交组合的F2 代均出现抗、感分离 ,说明HX 3与这 4个基因不等位。综合以上研究结果 ,HX 3具有 1个新的抗白叶枯病基因 ,暂命名为Xa 2 5 (t)。更多还原

【Abstract】 Using the mature embryo of a susceptible rice variety Minghui 63 as the explant,we have obtained a somaclonal mutant HX 3 through selection in vitro ,which has showed resistance to bacterial blight. In 8 successive years,the resistance of R 1 to R 9 generations of HX 3 was identified by ZJ173,a typical bacterial blight strain in Yangtsu River valley,and the results showed that the resistance of HX 3 was stable and heritable. Genetic analysis also indicated that the resistance of HX 3 to bacterial blight was under a dominant gene controlling. Using 32 bacterial blight strains collected in China,Philippines and Japan,the resistance spectrum of HX 3 and other 13 testers with different major dominant resistance genes were tested. Results of 2 years (1999～2000) experiment showed that HX 3 had a broad resistance spectrum,which seemed to be different with those of the other dominant resistance genes identified. Allelic tests were also conducted by crossing HX 3 with IRBB4,IRBB7,CBB12 and IRBB21,and the F 2 populations of each of the 4 crosses demonstrated resistant and susceptible plant segregation,indicating that the resistance gene in HX 3 different from Xa 4,Xa 7,Xa 12 and Xa 21 . All these results proved that there was a new resistance gene in HX 3. We have designated the new gene as Xa 25(t).更多还原