Marker Assisted pedigree breeding for improvement of an elite rice variety RNR 15048 (Telangana Sona) for Bacterial Leaf Blight and Blast resistance

Abstract:

Rice is the second most important food crop in the world after wheat. Bacterial Leaf blight (BB) and Blast are the two major diseases causing considerable yield losses in rice. RNR 15048 (Telangana Sona) (IET23746) is a popular variety in Telangana state with excellent cooking quality having a low glycemic index (51.72%), possessing Pi2 gene but having no durable resistance for blast and moderately susceptible to bacterial blight with weak culm. In this context, the present study was undertaken to develop breeding lines similar to RNR 15048 with resistance to BB (Xa21) and Blast (Pi54) diseases through marker-assisted selection. A cross was made between RNR 15048 and MTU1010 NIL to transfer strong culm character. F1s were checked for strong culm using a prostrate tester and crossed with ISM NIL, possessing Xa21 & Pi54 genes for both BB and blast. Foreground selection was carried out for BB and blast resistance genes (Xa21 & Pi54) by using gene-specific markers and true F1s (double heterozygous for BB and blast) were identified and forwarded to F2 generation. In F1 generation a total number of 76 F1 s were found to be heterozygous positive for both the target genes Xa21 and Pi54. In the F2 generation a total number of 84 plants were found to be homozygous positive for both the target genes Xa21 and Pi54. Genetic analysis studies in the F2 population revealed that the genes governing blast (Pi54) and BB (Xa21) resistance followed Mendelian inheritance.