1. Department of Crop & Soil Sciences, Washington State University, and Western Wheat Quality Laboratory, Agricultural Research Service, U.S. Department of Agriculture, E-202 Food Science & Human Nutrition Facility East, P.O. Box 646394, Washington State University, Pullman, Washington 99164-6394, and Biosciences Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Fargo, North Dakota 58105-5674