Breeding tools for Fusarium head blight and deoxynivalenol resistance in winter wheat (Triticum aestivum L.)
Fusarium head blight (FHB), caused primarily by 'Fusarium graminearum ' (Schwabe), is an important wheat disease that negatively affects quality and yield. Moreover, 'F. graminearum' produces deoxynivalenol (DON), a mycotoxin significant in agriculture, health and trade. Five types of response to FHB have been described previously, and a better understanding of these can be used to increase selection efficiency in breeding for resistance. Early, segregating generations of winter wheat populations, with known types of FHB resistance, were used in this study. The progenies were derived from a cross of Frontana (Type 1 FHB resistant donor parent) and Ruby (FHB susceptible parent), from WEKO6ODH4 (Type 2 FHB resistant donor parent, a Sumai 3 derivative) and 2737W (FHB susceptible parent), and from WEKO6ODH3 (Type 2 FHB resistant donor parent, a Sumai 3 derivative) and AC Ron (FHB susceptible parent). Quantitative trait loci (QTL) associated with FHB symptoms, DON accumulation, and Fusarium damaged kernels (FDK) were identified using microsatellite or simple sequence repeat (SSR) markers. As was expected, the QTL detected in the populations were not identical. The SSR markers identified and evaluated in this study could be used for marker assisted selection in early segregating generations because only a small amount of plant tissue was required, and heterozygous plants can be recognized. The identification of several types of resistance in early segregating generations of winter wheat will allow quicker pyramiding of genes toward improved FHB resistant cultivars. Transgressive segregants, and low heritability for resistance to FHB symptoms and DON accumulation were also detected in the populations studied. 'In vitro' and 'in vivo' methods for evaluating Fusarium resistance were compared and these methods confirmed that seedling resistance is not independent from spike resistance. Fusarium resistance at the seedling stage was positively correlated with DON content in the grain, weakly correlated with FHB index in the field, and negatively correlated with yield.