The Pi-ta gene in rice confers resistance to strains of the blast pathogen Magnaporthe grisea (Herbert) Borr. (anamorph Pyricularia oryza Cav.) containing the corresponding avirulence gene AVR-Pita in a gene-for-gene fashion. The Pi-ta gene is a typical nucleotide-binding site type resistance gene. Nucleotide sequences distinguishing the resistant Pi-ta and susceptible pi-ta alleles were previously identified and used for developing DNA markers for a resistant Pi-ta haplotype and three susceptible pi-ta haplotypes. In the present study, the existence of the Pi-ta gene in 141 rice germplasm accessions was rapidly determined using these markers