1. Department of Biological and Agricultural Engineering, Kansas State University, Manhattan, KS 66506.
2. Corresponding author. Phone: 785-532-2919. Fax: 785-532-5825. E-mail: dwang@ksu.edu
3. USDA-ARS Grain Marketing and Production Research Center, Manhattan, KS 66502.
4. USDA-ARS Crop Genetics & Breeding Research Unit, Tifton, GA 31793-0748.