1. Pcfruit, Research Station for fruit, Department of Pomology, Fruittuinweg 1, 3800 Sint-Truiden, Belgium.
2. Flemish Institute for Technological Research, VITO NV, Mol, Belgium.
3. KU Leuven, Department of Biosystems, Laboratory of Fruit Breeding and Biotechnology, Willem de Croylaan 42, 3001 Leuven, Belgium.