1. Department of Biological Sciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
2. Agriculture and Agri-Food Canada, Summerland Research and Development Center, Summerland, BC V5A 1S6, Canada
3. 3 Rivers Biotech, Coquitlam, BC V5A 1S6, Canada
4. Department of Agricultural Biology, Colorado State University, Fort Collins, CO 80523-1177, USA