One hundred seventy varieties or lines of wheat relatives,including 81 accessions of spelt and 27 accessions of Triticum compacturn from USA and Europe,4 accessions of semi-wild wheat collected from Tibet,China,and 58 accessions of synthetic hexaploid wheat from CIMMYT,were tested for their resistance to wheat powdery mildew at seedling stage.The results indicated that three spelt accessions,including Hubel and Leug collected from Switzerland and one Germany primary spelt line 69Z6.245 (PI348085) were found resistant to powdery mildew.Nineteen accessions among the 58 synthetic hexaploid wheat and two accessions of T.compactum were highly resistant to powdery mildew.The resistant germplasm will be uesful for powdery mildew resistance breeding of wheat.