Genetic analysis of resistance to bacterial blight (Xanthomonas oryzae pv. Oryzae Ishiyama) in some rice (Oryza sativa L.) lines

Genetics of resistance to a local isolate of Xanthomonas oryzae pv. oryzae causing bacterial blight was studied in four lines of rice (Oryza sativa L.) namely DR 285-5-6-6-2, DR 319-1-HR28, IET 8584 and IET 8585. Resistance of IET 8585 was controlled by two dominant independently inherited genes, while in the remaining two lines resistance was conferred by one dominant and one recessive gene each. Reaction of F₂ populations in intercrosses of resistant stocks showed that one of the dominant genes of IET 8585 is allelic to the dominant gene of DR 285-5-6-6-2, DR 319-1-HR28 and IET 8584. The resistance gene(s) of IET 8584 were nonallelic to the gene(s) of DR 285-5-6-6-2 and DR 319-1-HR28. In all, two dominant and two recessive genes were postulated to be conferring resistance in these four rice lines.