Kotasthane, A.S.Tiwari, P,K.Verulker, S.B.Chandrakar, (Smt.) G.Lakpale, N.Suma, Moka2016-12-162016-12-16201695 p.http://krishikosh.egranth.ac.in/handle/1/90580Subsequently, its incidence has been reported from different parts of Asia, northern Australia, Africa, and the USA and has become one of the three serious rice diseases. Enhancing genetic resistance has proven to be the most effective method to control the BB disease. The resistant mechanism of Oryza sativa (Os)– Xoo pathosystem attracted many researchers.The ability to quickly and reliably select desirable material, and to eliminate individuals that contain deleterious alleles is critical to the success of a plant breeding program. Genetic markers which facilitates the identification of favourable (or deleterious) alleles in a collection of diverse genotypes is referred to as marker assisted selection (MAS) (Dubcovsky 2004).Through conventional breeding we introgressed BLB resistance gene(s) xa13 and Xa21 from IRBB 55 into elite rice cultivar Karma Mahsuri. Marker assisted selection was done using linked molecular markers of xa13:-xa13 6070; Xa21:- RM21. We report herein a set of 15 rice genotypes with only xa13, 3 genotypes with only Xa21 and two genotypes carrying a combination of xa13 + Xa21 genes. High-resolution maps generated in silico around xa13 and Xa21 can be useful for the precise placement of a gene of interest and analysis of regional and sub regional rates of recombination and appropriate combinations of markers for marker assisted selection in plant-breeding.enThesis