Study on Enhancing Bacterial Blight Resistance of Hybrid Rice Restorer Lines through Marker Assisted Selection of the Xa23 Gene

The bacterial blight is one of the major diseases in rice.One effective control measure for bacterial blight is to breed resistance cultivars through molecular marker closely linked to the resistance genes.The rice bacterial blight resistance gene Xa23,carried by the donor parent IRBB23,was introduced into the restorer line Dongnanhui 012'by regular and back crossing and molecular(marker assisted selection.This research was carried out in low generation without resistance using molecular marker assisted selection with marker C189 closely linked to Xa23 gene,and in high and stable strains using seedling population identification technology.A series of precocious restore lines with homozygous target genes Xa23 and stable good agronomic characters were obtained through testing the flanking marker C189.The eight lines were subject to bacterial blight disease inoculation at the booting stages,and results showed that seven lines were resistant to the most destructive Xoostrain PXO 99(P6).Meanwhile,we also analyzed the main agronomic traits of the seven homozygous lines.These results clearly suggested that the marker C189 linked to Xa23 could be conveniently and effectively used in the bacterial blight resistance breeding programs of rice.