1. Boyce Thompson Institute for Plant Research, Tower Road, Cornell University, Ithaca, New York 14853-1801
2. Department of Genetics, Harvard Medical School, and Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114
3. Laboratoire de Genetique Moleculaire des Plantes, Université Joseph Fourier, BP 53, 38041 Grenoble Cedex 9, France
4. School of Food and Nutritional Sciences, University of Shizuoka, Shizuoka 422, Japan