QTL mapping of Fusarium head blight resistance in an elite winter wheat doubled haploid population

In Canada, Fusarium graminearum is the primary causal agent of Fusarium head blight (FHB) in wheat, resulting in yield and end-use quality losses. Resistance to FHB is complex and often involves multiple genes with relatively small effects. As a result, the current breeding strategy is to combine different types of FHB resistance into a single genotype. The breeding line 32C*17 showed strong FHB resistance under severe disease pressure in both Canada and Germany. Two hundred double haploid lines were made from a cross between 32C*17 and a moderately resistant line (18I*45). The 90K wheat Illumina Infinium iSelect single nucleotide polymorphism array was used to genotype this population. Replicated field trials inoculated with a F. graminearum macroconidial suspension were conducted at three locations in 2015 and two locations in 2016. Dual floret inoculations were performed in the greenhouse in a replicated trial. Inoculum used in all trials was a mixture of two isolates of 3-Acetyldeoxynivalenol producers and two isolates of 15-Acetyldeoxynivalenol producers. Plant height, disease incidence, disease severity and FHB Index were measured in the FHB field nurseries. Fusarium damaged kernels and the deoxynivalenol (DON) contents were determined tested from field nursery harvested grain samples. Greenhouse disease severity data was also estimated. Transgressive segregation was observed for all FHB traits measured. Multiple quantitative trait loci (QTLs) were detected including a QTL for plant height on chromosome 4B, which may contribute strong Type I resistance resulting in and lead to low FHB Index, FDK and DON. Further characterization of FHB resistance in this population is ongoing.