IDENTIFICATION AND MOLECULAR MAPPING OF POWDERY MILDEW RESISTANCE GENE PMG25 IN COMMON WHEAT ORIGINATED FROM WILD EMMER (TRITICUM TURGIDUM VAR. DICOCCOIDES)

Abstract

Powdery mildew caused by Blumeria graminis f. sp. tritici is one of the most economically important wheat diseases in many regions through out the world. N0308, a common wheat line contains powdery mildew resistance gene introgressed from wild emmer accession G25. Genetic analysis of the F2 populations and F3 families derived from the cross between N0308 and a susceptible common wheat cultivar Shaanyou 225 indicated a single dominant gene, temporarily designated PmG25, conferred resistance to powdery mildew race ‘Guanzhong 4’. Bulked segregant analysis and molecular markers were used to characterize the powdery mildew resistance gene PmG25. Eleven SSR markers (Xgpw1082, Xgpw3191, Xfcp1, Xfcp393, Xfcp394, Xgpw7425, Xwmc75, Xgwm408, Xwmc810, Xbarc232 and Xbarc142) and two EST-STS markers (BF482522 and BF202652) were linked with PmG25 on the long arm of chromosome 5B. The resistance gene was flanked by Xfc1/Xfcp393 and Xgpw3191, with genetic distances of 1.3 and 3.3 cM, respectively, and located on the chromosome bin 5BL-14- 0.75-0.76 in the test with a set of deletion lines. The powdery mildew resistance genes Pm36 and Ml3D232 have also been mapped to the region. The chromosome location and genetic mapping results suggested that the powdery mildew resistance gene derived from wild emmer G25 may be allelic or closely linked to Pm36.