1. Departments of Botany (S.M.A., A.P.-H., C.J.D.),
2. and Plant Science (A.P.-H., D.A.T., B.E.E.), University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
3. University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4Pacific Agri-Food Research Centre, Summerland, British Columbia, Canada V0H 1Z0 (D.A.T.)