Bacterial leaf blight (BLB) disease is one of the major diseases of rice, which can cause detrimental effect to the yield. To overcome this issue development of resistant varieties by utilizing resistant gene pool is the most effective strategy for the plant breeders. The current study was conducted in order to evaluate the potential of 182 rice genotypes against Bacterial leaf blight (BLB) at genotypic level. The trait-based SNP (Single nucleotide polymorphic markers) were employed to detect the presence or absence of BLB resistance genes (Xa4, Xa7, Xa13 and Xa21) in the genotypes. The genotypic results revealed that, 131 genotypes showed the presence of at least any one resistance genes studied. Interestingly, 48 genotypes did not show presence of any of the four resistance genes. The genes Xa4, Xa7, Xa13 and Xa21 were identified in 132, 2, 3 and 2 genotypes with frequency of 72.52%, 1.09%, 1.64% and 1.09% of genotypes, respectively. Notably, one genotype possessed two resistance genes (Xa4 and Xa7) and two genotypes possessed three resistance genes (Xa4, Xa13 and Xa21). Furthermore, cluster analysis grouped the 182 genotypes into two clusters, in which cluster I had genotypes not carrying any of the resistance genes and cluster II had genotypes carrying at least one or more than one resistance genes. The identified genotypes carrying multiple resistance genes could serve as a potential resource for BLB resistance targeted rice breeding programmes.

Bacterial leaf blight, Gene, Resistance, Rice and SNP

The present study highlighted that molecular validation is the fast and essential strategy to explore the variation of various rice genotypes for their potential against BLB disease. The genotypes having any one of the resistance gene can be utilized in crop improvement activities targeting for BLB resistance. The two identified multi-genic lines, which contain the genes Xa4, Xa13 and Xa21 would be a potential donor parents for developing BLB resistant varieties through marker assisted improvement programme in rice. Having multiple genes conferring resistance is a robust approach in the face of climate change, ensuring sustainable food security. This study further suggests that genotypes indicating resistance at molecular level should be evaluated at field level for further confirmation.

Lakshmikanth M.R., A. Mishra, Prakash Singh, P.N. Jagadev, B. Pradhan, K.C. Samal, S. Mohanty and R.L. Verma (2022). Molecular Screening of Rice (Oryza sativa L.) Genotypes for Bacterial Leaf Blight Resistance Genes using Trait-based SNP Markers. Biological Forum – An International Journal, 14(4a): 826-829.