2012 Annual Report
Resistance to new infectious strains of sunflower downy mildew. Sunflower is an important oil and confection seed crop in the US. Downy mildew is a serious disease of sunflower. ARS scientists in Fargo, ND, identified a total of nine new infectious strains of downy mildew in the last three years that overcome two genes widely used in commercial downy mildew-resistant hybrids. More importantly, they determined that 12 released USDA lines remain resistant to all known U.S. downy mildew strains. This information allows sunflower seed companies to use effective resistance genes to downy mildew in their hybrids, thus protecting the U.S. crop from this ever-present disease.
Identification of new sunflower pathogens. Most sunflower pathogens are well known, and identified by classical methods. New species of the fungus Phomopsis have been identified in the U.S. which cause similar symptoms on sunflower, and are only distinguishable by complex DNA analysis. Precise identification of these new species will allow pathologists and breeders to refine inoculation/evaluation methods to specifically find resistance to each species. This information will make the development of resistant germplasm and commercial hybrids more effective and precise.
New sunflower genetic lines for disease resistance. Sunflower is an important oil and confection seed crop in the US. Sclerotinia is the major fungal disease of sunflower. ARS scientists in Fargo, ND, will release up to 8 oilseed sunflower genetic lines in 2012. Each contributes new genetic diversity for Sclerotinia resistance in a high yielding genetic background that possesses favorable genes for oil quality and herbicide resistance. These genetic lines will provide the sunflower breeding community and sunflower producers new sources of resistance against the nearly complete devastation of sunflower when it is attacked by Sclerotinia diseases.
Knodel, J.J., Ganehiarachchi, G.A.S.M., Beauzay, P.B., Chirumamilla, A., Charlet, L.D. 2011. Impact of planting dates on a seed maggot, Neotephritis finalis (Diptera: Tephritidae), and sunflower bud moth (Lepidoptera: Tortricidae) damage in cultivated sunflower. Journal of Economic Entomology. 104(4):1236-1244.
Prasifka, J.R., Bradshaw, J.D., Lee, S.T., Gray, M.E. 2011. Relative feeding and development of armyworm, Mythimna (Pseudaletia) unipuncta (Haworth), on switchgrass and corn, and its potential effects on switchgrass grown for biomass. Journal of Economic Entomology. 104(5): 1561-7.
Kang, J., Onstad, D.W., Hellmich II, R.L., Moser, S.E., Hutchison, W.D., Prasifka, J.R. 2012. Modeling the impact of cross-pollination and low toxin expression in corn kernels on adaptation of European corn borer (Lepidoptera: Crambidae) to transgenic insecticidal corn. Environmental Entomology. 41(1):200-211.
Hulke, B.S., Bushman, B.S., Watkins, E., Ehlke, N.J. 2012. Association of freezing tolerance to LpCBFIIIb and LpCBFIIIc gene polymorphism in perennial ryegrass accessions. Crop Science. 52:2023-2029.