Genetic analyses of native Fusarium head blight resistance in two spring wheat populations identifies QTL near the B1, Ppd-D1, Rht-1, Vrn-1, Fhb1, Fhb2, and Fhb5 loci

Key message QTL analyses of two bi-parental mapping populations with AC Barrie as a parent revealed numerous FHB-resistance QTL unique to each population and uncovered novel variation nearFhb1. Fusarium head blight (FHB) is a destructive disease of wheat worldwide, leading to severe yield and quality losses. The genetic basis of native FHB resistance was examined in two populations: a recombinant inbred line population from the cross Cutler/AC Barrie and a doubled haploid (DH) population from the cross AC Barrie/Reeder. Numerous QTL were detected among the two mapping populations with many being cross-specific. Photoperiod insensitivity atPpd-D1and dwarfing atRht-B1andRht-D1was associated with increased FHB susceptibility. Anthesis date QTL at or near theVrn-A1andVrn-B1loci co-located with major FHB-resistance QTL in the AC Barrie/Reeder population. The loci were epistatic for both traits, such that DH lines with both late alleles were considerably later to anthesis and had reduced FHB symptoms (i.e., responsible for the epistatic interaction). Interestingly, AC Barrie contributed FHB resistance near theFhb1locus in the Cutler population and susceptibility in the Reeder population. Analyses of theFhb1candidate genesPFTandTaHRCconfirmed that AC Barrie, Cutler, and Reeder do not carry the Sumai-3Fhb1gene. Resistance QTL were also detected at the expected locations ofFhb2andFhb5. The native FHB-resistance QTL detected nearFhb1,Fhb2, andFhb5do not appear to be as effective asFhb1,Fhb2, andFhb5from Sumai-3. The presence of awns segregated at theB1awn inhibitor locus in both populations, but was only associated with FHB resistance in the Cutler/AC Barrie population suggesting linkage caused the association rather than pleiotropy.