1. Department of Plant Pathology, North Dakota State University, Fargo, ND 58102, U.S.A.
2. USDA-ARS Cereal Crops Research Unit, Edward T. Schafer Agricultural Research Center, Fargo, ND 58102, U.S.A.
3. Department of Computer Systems and Software Engineering, Valley City State University, Valley City, ND 58072, U.S.A.
4. Department of Plant Sciences, North Dakota State University, Fargo, ND 58102, U.S.A.