Validation of Quantitative Trait Loci Conferring Resistance to Fusarium Head Blight In Soft Red Winter Wheat.

Fusarium head blight (FHB), caused by Fusarium graminearum Schwabe [telomorph: Gibberella zeae Schwein.(Petch)], is recognized as one of the most-destructive diseases of wheat (Triticum aestivum L. and T. durum L.) and barley (Hordeum vulgare L.) worldwide. Breeding for FHB resistance must be accompanied by selection for desirable agronomic traits. Donor parents with two FHB resistance quantitative trait loci (QTL) Fhb1 (chromosome 3BS) and QFhs.nau-2DL (chromosome 2DL) were crossed to four adapted SRW wheat lines to generate backcross and forward cross progeny. F₂ individuals were genotyped and assigned to 4 different groups according to presence/ absence of both QTL. The effectiveness of these QTL in reducing FHB in F₂ derived lines will be assessed in a misted, inoculated scab nursery. Backcross derived progeny from four genetic backgrounds were planted in replicated plots and in the scab nursery in 2011. In one population, progeny were characterized by 961 polymorphic markers distributed throughout the genome. Associations with resistance, agronomic and quality traits will be analyzed and discussed. Backcross and F₂ derived progeny will be compared for suitability as breeding populations. The utility of F₂ populations as indicators of expression levels of QTL prior to extensive backcrossing will be explored and the influence of Fhb1 and QFhs.nau-2DL on FHB resistance and impact on agronomic traits on those same wheat populations will be investigated.