Systematic exploration, evaluation, and application of significant loci for Fusarium head blight resistance in wheat

Fusarium head blight (FHB), a serious disease in wheat, causes significant reductions in grain yield and quality worldwide. Marker-assisted selection can provide an effective tool for improving FHB resistance. Although many quantitative trait loci associated with resistance to FHB have been reported, few loci are currently available in breeding programs. The middle and lower reaches of the Yangtze River in China are areas that historically have experienced FHB epidemics, so that some local varieties may contain some valuable genes providing FHB resistance. In this study, association mapping was performed using 103 local cultivated varieties, and a previous QTL mapping using a recombinant inbred line (RIL) population from two locally popular parents, specifically Ningmai 9 and Yangmai 158, was integrated to identify nine candidate intervals. The corresponding Kompetitive Allele Specific PCR markers associated with FHB resistance were successfully developed and validated in 611 breeding lines. Four loci, namely QFhb.jaas-2D, QFhb.jaas-3A, QFhb.jaas-5A.2, and QFhb.jaas-6D, proved to be significantly related to FHB resistance in addition to Fhb1, and they could provide good resistance to FHB in the absence of Fhb1; the combination of multiple loci could produce a more stable resistance. These five markers were then applied in 211 breeding lines, and many resistance lines were obtained with different combinations of resistance loci. Additionally, QFhb.jaas-3A proved to be a highly selected locus, and eight differential genes in its interval were identified by genome and transcriptome analysis. This study provides additional gene resources and materials that could be used in FHB resistance breeding in wheat.