1. Department of Agricultural Sciences; Viikki Plant Science Centre; University of Helsinki; Helsinki Finland
2. Norwegian Institute of Bioeconomy Research; Ås Norway
3. Julius Kühn-Institut; Federal Research Centre for Cultivated Plants; Institute for Breeding Research on Fruit Crops; Dresden Germany
4. Department of Ecology and Resource Management; Norwegian University of Life Sciences; Ås Norway
5. Department of Biosciences; Viikki Plant Science Centre; University of Helsinki; Helsinki Finland