1. Department of Crop and Soil Science, Washington State University, Pullman, WA, 99164.
2. Corresponding author. Phone: (509) 335-8230. Fax: (509) 335-8674. E-mail: bbaik@wsu.edu
3. Department of Food and Nutrition, Gwangju Women's University, 165 Sanjeongdong Gwangsan-gu, Kwangju 506-713, Korea.