1. a Prince Edward Island Department of Agriculture and Forestry, P.O. Box 1600, Charlottetown, Prince Edward Island, Canada, C1A 7N3
2. b Agriculture and Agri-Food Canada, Crops and Livestock Research Centre, P.O. Box 1210, Charlottetown, Prince Edward Island, Canada, C1A 7M8
3. c Department of Plant Science, Nova Scotia Agricultural College, Truro, Nova Scotia, Canada, B2N 5E3