Marker-Assisted Breeding of Fusarium Head Blight Resistance in Wheat
Fusarium head blight (FHB) is one of the most destructive diseases of wheat (Triticum aestivum L. and T. durum L.) and barley (Hordeum vulgare L.) in warm and humid areas of the world (Schroeder and Christensen, 1963; Wang et al., 1982; Snijders 1990). FHB epidemics can cause significant yield losses, shriveled kernels, and deposition of vomitoxin (Deoxynivalenol (DON)) in the infected seeds which renders the grain unsuitable for human consumption and feed (McMullen et al., 1997). Wheat and barley losses caused by FHB epidemics in the USA during the 1990s were estimated at close to $3 billion U.S. dollars (Windels, 2000). The development and deployment of resistant germplasm is an environmentally sustainable method for the control of FHB. Several species of the Fusarium genus are known to cause FHB (Wiese, 1987). F. graminearum and F. culmorum
are the primary Fusarium species causing DON contamination and reduced grain quality. F. graminearum survives between wheat crops in living or dead host tissues (Zhu and Fan, 1989). Wheat planted after maize often has significantly more head blight than wheat planted after other crops. Therefore, reduced tillage in soil conservation systems increases the amount of inoculum present (Teich and Hamilton, 1985). Wheat production in Idaho ranks 5th in the nation in 2006. Adding FHB resistance to current cultivars is critical and valuable for our growers to maintain sustainable high quality grain production in national and world markets. FHB epidemics occurred in sprinkler-irrigated wheat and barley fields in south central and eastern Idaho in 1982 and 1984, resulting in estimated yield losses as high as 50% (Michuta-Grimm and Foster, 1989). Scab epidemics occurred in sprinkler-irrigated
spring wheat and barley fields in Montana in 2006 and 07 and resulted in estimated yield losses over 50% (Luther Talbert, personal communication). With the increase in corn production (for dairy and biofuel), and no-till or conservation tillage in the area, it would be beneficial to have an active FHB resistance program to insure that future cultivars carry some resistance if corn production, especially under no-till, continues to increase in acreage in the south central and south eastern part of the state. Changing production practices and increasing temperatures in the PNW, as predicted by climate models, may increase the risk of FHB. Therefore, incorporation of FHB resistance into existing germplasm may prevent or reduce future losses.