Marker enrichment of an FHB resistance QTL on chromosome 3B in SRWW

Fusarium head blight (FHB) is one of many fungal pathogens that affect wheat production resulting in significant economic losses. Phenotypic selection for FHB resistance in wheat is confounded by the large role of the environment, requiring many replications in inoculated nurseries to obtain reliable assessment of disease resistance. The quantitative nature of FHB resistance requires selection of plants with desirable gene combinations since no single gene provides complete resistance. As a result, there is an urgent need to develop easily assayed molecular markers closely linked to FHB resistance genes. The objective of this work is to enrich FHB QTL on chromosome 3B with markers. Fine mapping is being conducted in two populations (1) a backcross population of 1,056 plants from the cross SSMPV57*2/Massey and (2) a HIF population of 120 plants selected from the recombinant inbred line Truman/MO94317 population. Mapping is being done with SSR and SNP markers targeted to a 40 cM interval near the centromere of chromosome 3B. Homozygous recombinant lines will be evaluated in the greenhouse to locate the FHB resistance gene(s) in these populations as Mendelian traits. Marker trait association will also be evaluated in an FHB association mapping panel to validate predictability across diverse germplasm. Markers with strong linkage to the FHB QTL will be converted to a high-throughput gel free assay. Given the complexity of inheritance of FHB resistance, it is imperative that simple and high throughput diagnostic SNP markers with strong genetic correlation be develop for marker assisted selection.