1. Department of Horticulture, Viticulture and Oenology, Adelaide University, Waite Campus, PMB 1, Glen Osmond, South Australia 5064, Australia, and Cooperative Research Centre for Viticulture, PO Box 154, Glen Osmond, South Australia 5064, Australia, and The Australian Wine Research Institute, Waite Campus, PMB 1, Glen Osmond, South Australia 5064, Australia