Transfer of FHB resistance from Thinopyrum elongatum to spring wheat.

Fusarium head blight (FHB) is a devastating disease of cereals in all temperate regions of the world. Breeding for resistance is occurring incrementally. Additional sources of resistance are being sought and incorporated into wheat. Additional resistance to the disease is being found in the tertiary gene of pool of wheat. The best source of resistance identified thus far is in Thinopyrum elongatum (2n = 2x = 14, EE genome). The complete series of addition and substitution lines of E genome chromosomes in a wheat background (cv Chinese Spring) has previously been produced (Dvovak). The resistance was localized to chromosome 7E.
The percent of infected florets of the 7E(7D) substitution line was % compared to % in the parental cultivar.
The Ph1b system was used to induce recombination between chromosome 7E and wheat chromosomes of homoeologous group 7. This was done by crossing the 7E(7D) substitution line with the Ph1b mutant and backcrossing once to Chinese Spring.
The recombinants produced in this way were screened for FHB resistance and with 7E-specific SSR markers designed by the Ouellet lab to select out lines that carried FHB resistance and contained the shortest possible segment of chromosome 7E.
Recombinants with FHB resistance and 7E integration in the distal portion of wheat chromosome 7D L were selected.