1. Geisenheim Research Center, Department of Pomology, Geisenheim, Germany
2. RheinMain University of Applied Sciences, Geisenheim, Germany
3. Bioforsk, Grasland and Landscape Division, Kvithamar, Stjørdal, Norway
4. Department of Agriculture and Ecology, Copenhagen University, Copenhagen, Denmark
5. Agroscope Changins-Wädenswil Research Station ACW, Changins-Wädenswil, Switzerland
6. D3A Università Politecnica delle Marche, Ancona, Italy