Effects of two major fusarium head blight resistance QTL verified in a winter wheat backcross population

Many Fusariurn head blight (FHB) [caused by Fusarium graminearum Schw. and F. culmorum (W.G. Sm.) Sacc.] quantitative trait loci (QTL) have been detected in both spring and winter wheat (Triticum aestivum L.). However, a QTL validation has not been performed in winter wheat. We report on the verification of resistance QTL in winter wheat, which had been previously mapped in a Dream/Lynx population. The QTL intervals of chromosomes 7BS, 6AL, and 2BL were enriched with amplified fragment length polymorphism (AFLP) markers. For a more precise estimation of the QTL effects and their influence on plant height and heading date, BC 2 F 4 lines were created by marker-assisted selection and examined for FHB resistance. The phenotypic effects of the two main QTL on chromosomes 6AL and 7BS confirmed the previous results of the original mapping population. In the backcross population, QTL6AL and QTL7BS reduced FHB severity individually by 27% each relative to lines without resistance alleles. Both QTL had an effect on plant height, resulting in taller plants being more resistant. The combination of both QTL decreased disease severity most effectively (36%). The successfully validated QTL on chromosomes 6AL and 7BS are designated Qfhs.IfI-6AL and Qfhs. IfI-7BS, respectively. The best genotypes carried one or both of the major QTL, displaying their importance for disease resistance. In contrast to spring wheat, where QTL have been identified in an exotic genetic background, the resistance QTL validated in this study already reside in an adapted genetic background with excellent agronomic performance.