FHB Resistant Wheat through Transgressive Segregation

Fusarium head blight (FHB), also well known as scab, is a devastating fungal disease of small-grain cereals including barley and bread and durum wheat, resulting in severe yield and quality losses. FHB is also a food safety concern due to the contamination of mycotoxins on crops. The most practical and effective solution to address FHB is to develop resistant cultivars. Due to limited resistant resources, breeding FHB resistant wheat has relied almost exclusively on the resistance from the Chinese landrace Sumai 3 and its derivatives that typically  display poor agronomic traits and low end-use quality. Sumai 3 derives from a cross of two moderately susceptible parental lines, a phenomenon called transgressive segregation. This demonstrates that transgressive segregation can be exploited as an alternative approach to develop good FHB resistant wheat cultivars. More recently, Emerson, the first registered FHB resistant winter wheat variety in Canada was also developed by the trangressive segregation, verifying this hypothesis. Here, a doubled haploid population was generated from two Canadian Spring wheat lines displaying moderate type II susceptibility to FHB.  Strong Type II FHB resistance was observed in ~6% of progenies in greenhouse trials, demonstrating the potential practicality of this approach to develop FHB resistant Canadian Spring bread wheat. QTL analysis was performed to determine the genetic architecture underlying the transgressive segregation of FHB resistance in this population. These findings will contribute to our  understanding of FHB resistance conferred by transgressive segregation and assist breeders in selecting appropriate parental lines to maximize the breeding potential for FHB resistance via this approach.