Development of restorer lines of rice (Oryza sativa L.) resistant to bacterial blight through marker aided pedigree selection (MAPS)

Biotic stresses that rob the yield advantage imparted through heterosis breeding can be retained by developing parental lines with inbuilt resistance. Bacterial leaf blight (BB) is one of prime diseases of rice, causing huge yield losses throughout the world. Here we have successfully demonstrated development of restorer lines with inbuilt resistance to bacterial leaf blight by Marker Aided Pedigree Selection (MAPS) - phenotypic selection, phenotyping and marker aided selection in the segregating generations for selecting desirable phenotype with target genotype of resistance genes. Phenotyping for bacterial leaf blight was conducted in F2 population developed from crossing KPG OS-722R with one donor KCMS2001 and 148 agronomically superior plants from putatively resistant plants were selected and genotyped for presence of Xa21 and xa13 genes by using linked markers pTA248 and xa13 promo, respectively. A total of 24 plants out of 148 plants were genotyped, selected and advanced to next generation. Out of 24 F3 progenies grown, 14 agronomically superior progenies were identified and one plant from each progeny was selected. Phenotyping for BB was conducted on 14 F4 lines under field conditions and 11 resistant lines were selected. After evaluation of per se performance and restoration ability of 11 lines, a total of three lines with strong resistance to BB and superior agronomic traits were selected. This work clearly demonstrates development of inbuilt resistant new restorer lines for BB with a lot of saving in time and other resources.