Validation of Fhb1 and QFhs.Nau-2DL In Several SRW Wheat Breeding Populations.

The use of exotic resistance quantitative trait loci (QTL) provides one strategy for breeding wheat cultivars resistant to Fusarium Head Blight (FHB).  The success of this approach depends on 1) effectiveness of the QTL in diverse genetic backgrounds, and 2) the effects of the QTL on agronomic and quality traits.  In this study, we evaluated two QTL, Fhb1 (chromosome 3B) and QFhs.nau-2DL (chromosome 2D) in this context. To validate both QTL in diverse genetic backgrounds, we measured FHB index, Fusarium damaged kernels (FDK) and deoxynivalenol (DON) concentration in inbred lines from five crosses in the scab nursery at Lexington, KY in 2010 and 2011: Cross 12 (26R58/VA01W-476//KY97C-0574-01), Cross 17 (25R54/VA01W-476//KY97C-0574-01), Cross 19 (25R54/VA01W-476//KY97C-0554-02), Cross 40 (25R78/Cumberland//VA01W-476) and Cross 42 (25R23/KY93C-1238-17-1//VA01W-476). The populations were also grown in yield trials at Lexington (2010 and 2011) and Princeton (2011), KY for measurement of agronomic and quality traits.  In addition to assessing FHB levels and quality traits by traditional methods, we also used whole grain assays and whole kernel NIR to predict quality traits, and NIR to estimate FDK and DON. In 2010, Fhb1-derived resistance significantly reduced FDK and DON in 5 and 4 crosses, respectively. QFhs.nau-2DLb significantly reduced FHB index in 1 cross, FDK in 1 cross and DON in 2 crosses.  Both QTL significantly affected yield, test weight and milling and baking quality traits but not in a consistent direction or in all crosses. Correlation of NIR-FDK and FDK was r = 0.61 and 0.84, for crosses 19 and 42, respectively. Correlation of NIR-DON and DON was r = 0.61 and 0.58 in the same crosses. Both QTL can reduce FHB in soft red winter wheat without significant negative impacts on agronomic and quality traits.  However, expression levels of the QTL can be expected to vary according to genetic background.