Validation and Marker Assisted Selection for a Novel QTL Q.DB.Ui-7DS Associated with Dwarf Bunt Resistance of Winter Wheat.

Dwarf bunt [Tilletia contraversa Kühn (syn. Tilletia controversa)] is a destructive disease of wheat (Triticum aestivum L.) that reduces grain yield and quality. A number of genes conferring resistance to dwarf bunt have been used by breeding programs for nearly one hundred years. However, very few markers were identified that can be used in selection of dwarf bunt resistance.  One QTL Q.DB.ui-7DS was identified in a recombinant inbred line (RIL) population derived from the bunt resistant germplasm, Idaho 444 (IDO444) and the susceptible cultivar, Rio Blanco, which explained 32 to 56% of phenotypic variation among the four field trials. This QTL was validated and additional QTL was identified in one winter wheat dihaploid (DH) population. Molecular markers identified in the present study were used to characterize bt genes in dwarf bunt differential lines, known resistance sources, and resistant cultivars.