[Mapping of a new resistance gene to bacterial blight in rice line introgressed from Oryza officinalis]

Rice line 'B5', which was derived from the wild rice Oryza officinalis Wall ex Watt through introgression, has been proved to be high resistant to brown planthopper, whitebacked planthopper and bacterial blight (Xanthomonas oryzae pv. oryzae). In this study, the resistance to bacterial blight of 187 recombinant inbred lines (RILs) from a cross between ' B5' and 'Minghui63' were evaluated and RFLP markers linked to the resistance gene were identified by bulked segregant analysis. Analysis of the molecular marker linkage map and the data of the lesion length of RILs located the resistant gene within a 1. 3 cM region flanked by RFLP markers C904 and R596 on chromosome 1. This locus contributed to 52.96% of the phenotypic variance of resistance in the population, and is considered to be a new locus as compared with other resistant genes to bacterial blight that have been reported. We tentatively designate this gene as Xa29(t). This newly tagged gene introgressed from wild rice is valuable to molecular marker-assisted selection for multiple resistant materials in rice breeding programme. Furthermore, it provides information for cloning the resistant gene Xa29(t) in rice.