Tibet Development and Breeding Application of the Fluorescence Molecular Marker of Rice Bacterial Blight Resistance Gene Xa7

Abstract

In this study, the closely linked fluorescence molecular marker PM-Xa7 of  Xa7  gene was developed on the basis of sequence difference between the resistant variety ‘IRBB7’ containing  Xa7  and other nine bacterial blight susceptible rice varieties, and combine with PARMS technology (Penta-primer amplification refractory mutation system). Genotypes of  Xa7  were identified in 72 rice germplasm and the bacterial blight resistance level of ‘Mei B’ was improved by backcross and screening with this marker. The results showed that two rice germplasms containing  Xa7  were screened out from 72 rice germplasm; By introducing the resistant  Xa7  gene from ‘IRBB7’ into ‘Mei B’ with PM-Xa7, a stable new maintainer with resistance to bacterial blight was successfully obtained. The bacterial blight resistant fluorescence signal was detected in 289 plants and the bacterial blight susceptible fluorescence signal was detected in 93 plants of BC 2 F 2 population generated from ‘IRBB7’ and ‘Mei B’, and the genotypes were consistent with the phenotypes of  Xoo  inoculation. These research results indicated that PM-Xa7 can be effectively used for the marker-assisted breeding of bacterial blight resistant rice variety with the resistant Xa7  gene.