Validation of Fhb1 and QFhs.nau-2DL in several soft red winter wheat populations

Exotic resistance quantitative trait loci (QTL) such as Fhb1 and QFhs.nau-2DL provide one strategy for breeding wheat (Triticum aestivum L.) cultivars resistant to Fusarium head blight (FHB). The first objective of this study was to evaluate the effectiveness of these QTL in reducing FHB in diverse genetic backgrounds and to measure their impact on agronomic and quality traits. Lines from five susceptible × resistant crosses were evaluated in the FHB nursery at Lexington, KY, in 2010 and 2011. The populations were also grown in yield trials at Lexington (2010 and 2011) and Princeton (2011), KY, to measure agronomic and quality traits. Fhb1 reduced Fusarium damaged kernels (FDK) by 32% and deoxynivalenol (DON) concentration by 20%. QFhs.nau-2DL reduced FDK by 29% in two of five populations and DON by 24% in four of five populations. Significant QTL effects (P < 0.05) on agronomic and quality traits were observed although impact was small. One cycle of direct or indirect simulated phenotypic selection was effective at reducing DON levels. The frequency of Fhb1-homozygous resistant lines among the phenotypically selected lines was higher than the frequency of QFhs.nau-2DLhomozygous resistant lines. The second objective was to assess the effectiveness of nearinfrared reflectance (NIR) to estimate damage from FHB. Near-infrared reflectance-based predictions of FDK and DON showed that FDK measured by NIR was at least as good as FDK measured by air separation in predicting DON in four of five populations.