1. USDA-ARS; Corvallis OR 97331
2. USDA-ARS, NFSPRC; Corvallis OR 97331
3. Plant and Environmental Sci., Univ. of California; Davis CA 95616-8627
4. USDA-ARS; National Program Staff; Beltsville MD 20705
5. Crop and Soil Sci., Oregon State Univ.; Corvallis OR 97331-7306