1. Department of Plant Physiology and Biophysics, University of Würzburg, D-97082 Würzburg, Germany
2. Aiken Forestry Sciences Laboratory, U.S. Department of Agriculture Forest Service, Burlington, Vermont 05402
3. Department of Arboriculture and Pomology, University of Turin, I-10095 Grugliasco, Italy
4. Grapevine Breeding and Biology Centre, Italian National Research Council, I-10095 Grugliasco, Italy