Abstract

Powdery mildew caused by Blumeria graminis f. sp. tritici is one of the most devastating diseases of wheat in China and worldwide. A powdery mildew resistance gene, originated from wild emmer accession G25, transferred into a common wheat line N0308. F₂population was established by crossing N0308, resistance to powdery mildew race Guanzong 4, with susceptible line Shaanyou 225. The segregation of phenotype accorded an expected ratio 3:1. The results indicate that the powdery mildew resistance gene in N0308 is controlled by a single dominant gene, designated temporarily as PmG25. SSR markers and the bulk segregant analysis were used to characterize the powdery mildew resistance gene PmG25. Six SSR markers such as Xgpw7425, Xwmc75, Xgwm408, Xwmc810, Xbarc232 and Xbarc142 were located on the distal of resistance gene PmG25with genetic distance 7.4, 9.4, 11.2, 22.3, 25.4 and 29.3 cM, respectively. All markers were placed on chromosome 5BL using Chinese Spring nulli-tetrasomic and ditelosomic lines, suggesting this gene might be located on the long arm of chromosome 5B.

Key words: Chromosomal location, SSR markers, powdery mildew, resistance genes, wild emmer