1. Commonwealth Scientific Industrial Research Organization, Plant Industry, Horticulture Research Unit, P.O. Box 350, Glen Osmond, South Australia 5064, Australia (A.V.-S., A.M.K.); and
2. Department of Plant Science, Waite Campus, University of Adelaide, P.M.B. 1, Glen Osmond, South Australia 5064, Australia (A.V.-S.)