1. Nestlé Research Center, 101 Avenue Gustave Eiffel, F-37390 Notre Dame d'Oé, France; Nestlé Research Center, P.O. Box 44, CH-1000 Lausanne 26, Switzerland; Nestlé R&D Center Badajoz, E-06080 Badajoz, Spain; and Department of Plant Breeding, Cornell University, Ithaca, New York 14853