1. Agriculture and Agri-Food Canada; Potato Research Centre; PO Box 20280 Fredericton NB Canada E3B 4Z7
2. Dep. of Environmental Science; Nova Scotia Agricultural College; PO Box 550, 21 Cox Rd. Truro NS Canada B2N 5E3
3. Nafferton Ecological Farming Group; Newcastle Univ.; Nafferton Farm Stocksfield Northumberland NE43, 7XD UK
4. Agriculture and Agri-Food Canada; Brandon Research Centre; Grand Valley Rd. Brandon MB Canada R7A 5Y3
5. Agriculture and Agri-Food Canada, Greenhouse and Processing Crop; Research Centre; Harrow ON Canada N0R 1G0