FHB resistance breeding in durum wheat: progress and perspectives

Fusarium head blight (FHB) in durum wheat causes severe economic losses and the associated mycotoxin
is a food and feed safety issue. Consequently breeding for resistance to FHB in durum wheat is of highest
priority in Canada. Enhancement of FHB resistance in durum wheat has been made, with progress from
predominantly susceptible to a proportion of lines with intermediate resistance in advanced breeding
materials. Improving resistance is slow because of lack of variation in elite germplasm, and the trait is
controlled by many minor effect genes highly affected by environmental conditions. The challenge is
compounded by the requirement to recombine FHB resistance with other important traits such as leaf
spotting disease resistance or midge resistance while maintaining the complex grain quality and agronomic
package of Canada Western Amber Durum. Recent initiatives in FHB resistance breeding include
increasing the number and size of FHB nurseries, selection for FHB response at earlier generations, use of
recurrent selection, crossing with resistant hexaploid lines, infusion of more resistant exotic germplasm and
wild relatives, use of DNA markers, and adoption of genomic selection. Recently developed genomic tools
are being used with phenotyping bi-parental, association mapping, and nested association mapping panels
to identify new quantitative trait loci (QTL) and to develop high throughput single nucleotide polymorphism
(SNP) markers. Ultimately discoveries from this research are being funnelled towards large-scale marker
assisted selection (MAS) in our breeding programs. We anticipate the application of sustained and
integrated approaches in FHB resistance breeding will lead to durum varieties with resistance enhanced
beyond the current intermediate level.