Introgression of blast and bacterial blight disease resistance genes in a rice genotype ADT43 through marker assisted back cross breeding.

ABSTRACT

Bacterial Leaf Blight (Xanthomonas oryzae pv. oryzae) and blast (Magnaporthe oryzae) are the major biotic stresses around the rice-growing zones of the world. The development of resistant varieties through Marker Assisted Backcross Breeding is the utmost economical and eco-friendly method for achieving stable yield. Amongst the resistance genes recognized, Xa21 and Pi54 possess broad-spectrum resistance to many Xoo and blast strains around the world. In the present study, we have effectively introgressed a Bacterial Blight resistance gene (Xa21) and a blast resistance gene (Pi54) into susceptible variety ADT43 from RP-Bio-Patho-2 coupled with phenotypic selection for agronomic, cooking quality and grain traits through MABC. MABC was sustained till BC2F2 generation with specific markers pTA248 for Xa21 and Pi54MAS for Pi54 resistance genes. A set of SSR markers for parental polymorphism were utilized for maximum regaining of recurrent parent genome in each backcrossing. "Positive plants" from BC2F1 were selfed to generate BC2F2 and the homozygous lines for bacterial leaf blight and blast resistance genes were identified for further assessment.