1. USDA-ARSVegetable and Forage Crops Research Unit 24106 N. Bunn Rd. Prosser WA 99350
2. Dep. of Crop and Soil SciencesMichigan State Univ. East Lansing MI 48824
3. Pioneer Hi-Bred International, Inc. 7250 NW 62nd Ave Johnston IA 50131
4. Dep. of Plant SciencesNorth Dakota State Univ. Fargo ND 58105