1. Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos , 28933 Móstoles, Madrid , Spain
2. Agriculture and Forestry Division , Canton Lucerne, 6210 Sursee , Switzerland
3. Institute of Agricultural Sciences, ETH Zurich , 8092 Zurich , Switzerland
4. Cultivation Techniques and Varieties for Arable Crops, Agroscope , 1260 Nyon , Switzerland