1. Cooperative Research Centre for Viticulture, P.O. Box 154, Glen Osmond, South Australia 5064, Australia; The Australian Wine Research Institute, P.O. Box 197, Glen Osmond, South Australia 5064, Australia; and Department of Horticulture, Viticulture and Oenology, Faculty of Agricultural and Natural Resource Sciences, University of Adelaide, Glen Osmond, South Australia 5064, Australia