1. Horticultural Crops Research Unit, U.S. Department of Agriculture, Agricultural Research Service, 3420 North West Orchard Avenue, Corvallis, Oregon 97330-5014, Department of Horticulture, Oregon State University, Corvallis, Oregon 97331-4003, Department of Chemistry, Oregon State University, Corvallis, Oregon 97331-4003, and Washington State University, Southwestern Washington Research Unit, 1919 North East 78th Street, Vancouver, Washington 98665-9752