Identification of BLB resistant genes in some rice varieties for development of high yielding bacterial leaf blight tolerant types

Abstract

Aim : To identify bacterial leaf blight resistant genes in some rice varieties so that these resistant varieties can be used as a good source of donor for BLB resistant genes in genetic enhancement program. Methodology : A total of sixty-one rice genotypes including resistant and susceptible checks were screened in field condition by artificial inoculation using 1X020 strain of Xoo for two years (Kharif 2016 and 2017). These varieties were also genotyped for seven SSR markers tagged with major BLB resistant genes, Le.,Xa4, xa5, xa13 and Xa7. Results : In artificial screening, significant disease development was recorded and the varieties were categorized using disease scoring scale of IRRI, 1996 where seven cultivars exhibited resistance, while twenty-seven were found to be moderately resistant. In genotyping, there was distinct difference in banding position for resistant and susceptible genotypes. Genotypes having resistant disease reaction, carrying BLB resistant genes were identified. Interpretation : Genotypes IR-64, IR-68144-2b-2-2-3-1-127, Ratna, Surjamukhi, Kalinga-2, Azucena and Zheshan-2 expressed bands of RM markers closely linked toXa4, xa5, xa13 and Xa7BLB resistant genes and field testing also confirmed resistant host reaction against pathogens.