1. Grand Forks Human Nutrition Research Center, Agricultural Research Service, U.S. Department of Agriculture, Grand Forks, North Dakota 58203; Plant Science Research Unit, Agricultural Research Service, U.S. Department of Agriculture, and Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota 55108; and Hard Red Spring and Durum Wheat Quality Laboratory, Red River Valley Agricultural Research Center, Agricultural Research Service, U.S. Department of Agriculture, Fargo,...