1. Laboratory for Plant Breeding, Wageningen University, P.O. Box 386, NL-6700 AJ Wageningen, The Netherlands
2. Louis Bolk Institute, Hoofdstraat 24, NL-3972 LA Driebergen, The Netherlands
3. Department of Crop and Soil Sciences, Washington State University, Mount Vernon Northwest Washington Research & Extension Center, Mount Vernon, WA, USA
4. Research Institute for Organic Farming (FiBL), Frick, Switzerland
5. Department of Horticulture, Oregon State University, Corvallis, OR, USA
6. Nafferton Ecological Farming Group, Nafferton Farm, Newcastle University, Stocksfield, Northumberland, United Kingdom