QTL Mapping for Powdery Mildew (Erysiphe graminis DC. f. sp. hordei EM Marchal) Resistance in Barley (Hordeum vulgare L.)

Powdery mildew, caused by Erysiphe graminis DC. f. sp. hordei EM Marchal, is a serious disease of Barley (Hordeum vulgare L.). In this study, we used molecular markers to identify the chromosomal locations carrying genes for powdery mildew resistance and to estimate the effect of each gene. Doubled haploid lines derived from Steptoe×Morex (S/M), Harrington×TR306 (H/T) and their parental were inoculated with five powdery mildew strains. Several quantitative trait loci (QTL) controlling E. graminis resistance were found and lacated on chromosome 4H, 5H, 6H and 7H in S/M. On the other hand, no QTL was detected in H/T but Harrington had a major resistant gene (Mlg) for powdery mildew resistance. Maker-assisted selection was conducted to examine the effect of accumulation for mildew resistance. There was a significant interaction between QTLs lacated in 4H and 7H, which suggested the presence of an epistatic effect between these QTLs.