Friday, June 11, 2010
Local Quest for Resistance to Fusarium Head Blight
Fusarium Head Blight (FHB) or Scab is a new fungal disease of wheat in Idaho. 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%. FHB epidemics in spring wheat occurred in sprinkler-irrigated wheat and barley fields in Montana in 2006 and 07 and resulted in estimated yield losses over 50% while infection was high (10 to 50%) in some adapted cultivars in wheat fields in Aberdeen in 2009.
Fusarium species reduce yields and produce mycotoxins like deoxynivalenol (DON) that in elevated amounts pose significant public health hazards to animals and humans.
Traditionally, environmental conditions in Idaho allow for the production of high quality, toxin free wheat grain that meets the needs of many end-users. With the increase in corn production, conservation tillage, and increasing temperatures in the PNW, there is a risk of increased FHB. Incorporation of resistance into existing germplasm may prevent or reduce future losses.
Evaluation of FHB resistance can be difficult using phenotypic evaluation as the disease nursery cannot be set up in the field in Aberdeen.
Jianli Chen, wheat breeder at University of Idaho, initiated a project in 2008 and evaluated over two hundred lines grown in Idaho and the Pacific Northwest using marker-assisted selection (MAS) in collaboration with the Western USDA genotyping center in Pullman, Washington.
Based on the preliminary evaluation, quite a few lines have some resistance to FHB. To determine if those lines have a functional gene against FHB infection and colonization, Chen initiated multi-state collaborations and conducted evaluations for spring wheat genotypes in the disease nurseries at the University of Minnesota in 2008 and in Bozeman at Montana State University in 2009. Winter wheat was tested at Virginia Tech in 2009 and 2010.
In most cases, field resistance of those lines inoculated by F. graminearum aligned well with their marker evaluations. Supported by Idaho wheat grower funds, a greenhouse screening system has been established.
In the next few years, Dr. Chen is going to use an integrated system combining marker-assisted selection with greenhouse and field screening to identify and develop adapted spring and winter wheat cultivars for Idaho and PNW growers that are resistant to FHB.