1. North Dakota State University, Department of Biological Sciences, P.O. Box 6050, Fargo, ND 58102, USA
2. USDA-ARS Red River Valley Agricultural Research Center, Biosciences Research Laboratory, 1605 Albrecht Boulevard North, Fargo, ND 58102, USA
3. North Dakota State University, Department of Statistics, 1320 Albrecht Blvd, Fargo, ND 58102, USA