1. Dep. of Crop and Soil Science Oregon State University 253 Crop Science Building Corvallis OR 97331‐3002
2. Departamento de Producción Vegetal, Est. Exp. “Dr. Mario A. Cassinoni”, Facultad de Agronomía Universidad de la República Ruta 3, Km. 373 Paysandú 60000 Uruguay
3. USDA‐ARS Washington State University Pullman WA 99164‐6430
4. Dep. of Plant Sciences and Plant Pathology Montana State University Bozeman MT 59717