1. 1USDA-ARS, Northern Crop Science Laboratory, Fargo, North Dakota, USA
2. 2Iowa State University, North Central Regional Plant Introduction Station, Ames, Iowa, USA
3. 3Department of Crop Sciences, University of Illinois, Urbana, Illinois, USA
4. 4Vernon Research and Extension Center, Texas A&M AgriLife, Vernon, Texas
5. 5State Plant Breeding Institute, University of Hohenheim, Stuttgart, Germany
6. 6Panhandle Research & Extension Center, University of Nebraska, Scottsbluff, Nebraska, USA