A spceies-specific repeated sequence, pHvN-AU62, was cloned from Haynaldia villosa, a wheat relative of grea improtance, It strongly hybridized to H. Villosa, but not to wheat. In situ hybridization ocalized this sequence to six of seven H. villosa chromosome pairs in iclomeric or sub-telomeric regions, Southern hybridization to wheat-H, villosa additon lines that chromosomes 1V through 6V escaped detection, In addition to H. villosa, several Triticeae species were identified for a high aboundance of the PHvNAU62 repeated sequence, among which Thinopyrum hassurabicum and Leymus racemosus produced the strogest signals. Scquence analysis indicated that the cloned fragment was 292 bp long, being AT rich (61%). and showed 67% homology of pSc 7235, a rye re[eated scquence. Isochizomer analysis suggestedthat the present repeated sequence was heavily methylated at the cylosine of the CpG dimer in the genome of H. cillosa. It was also demonstrated that pHvNAU62 is useful in tagging the introduced 6VS chromosome arm. which confers a resistance gene to wheat powdery mildew, in the segregating generations.