Molecular Screening and Diversity of Blast Resistance Genes in Some Wild and Local Rice (<i>Oryza sativa</i> L.) Genotypes of Bangladesh

Rice blast, caused by the pathogenic fungus Magnaporthe oryzae, is a highly destructive disease of rice that leads to significant reductions in crop yield each year and poses a serious threat to rice production worldwide.Utilizing R genes to develop resistant varieties continues to be the most cost-effective and efficient approach for managing rice blast.Molecular screening of important blast resistance genes of rice and their allelic diversity were assessed in forty eight wild and local rice genotypes of Bangladesh using ten previously synthesized gene-based SSR markers.A varying range between 18.7% to 87.5% was seen in the genetic frequencies of ten key blast resistance genes.Fourteen genotypes possessed maximum eight blast resistance genes while, nine of the genotypes had seven blast resistance genes.Nine genotypes contained six blast resistance genes and five genotypes had a minimum of two blast resistance genes.At least five positive pieces of the predicted product size were occupied by thirty-five genotypes, among total forty eight genotypes.These findings are important for identifying and incorporating functional resistance genes from Bangladeshi local germplasms into the elite cultivars by using marker-assisted selection and providing better resistance to blast.Marker analysis of resistant and susceptible genotypes using ten RAPD showed that, markers OPA 5, OPF 9 and OPH 18 clearly differentiate resistant genotypes BAU dhan-3 from susceptible genotypes BRRI dhan 28 and BRRI dhan 29 indicating the potentiality of these markers to identify blast resistant rice genotypes and use in marker assisted breeding (MAB) to develop blast resistant high yielding rice varieties in Bangladesh.