Fusarium ratings in Ontario winter wheat performance trial (OWWPT) using an index that combines Fusarium head blight symptoms and deoxynivalenol levels

Fusarium head blight (FHB) is one of the most serious diseases of wheat (Triticum aestivum L.). FHB reduces grain yield and quality, and the fungus produces mycotoxins, such as deoxynivalenol (DON). The most practical way to control FHB is through the development of resistant cultivars. In addition to exotic sources of resistance (such as cultivars Sumai 3 and Frontana), native sources of resistance are commonly used in winter wheat breeding programs in North America. In 1996, 2000, and 2004 severe epidemics of FHB cost the winter wheat industry in Ontario, Canada combined over $200 million. All wheat grown in Ontario is entered in the Ontario Winter Wheat Performance Trial (OWWPT) and tested every year for Fusarium resistance and DON level in three inoculated FHB nurseries. The objective of this study is to explain how the index that accounts for FHB symptoms and DON level jointly was developed, and how stable the performance of the cultivars grouped to susceptibility classes has been over a number of years. The index is related to Fusarium susceptibility classes (moderately resistant - MR, moderately susceptible - MS, susceptible - S and highly susceptible - HS), robust, stable, open-ended (old cultivars out, new cultivars in) and useful to farmers in making cultivars selection decisions. This information is available to growers and industry through the website www.gocereals.ca.