1. Horticulture, Swedish University of Agricultural Sciences, P.O. Box 103, SE-230 53 Alnarp, Sweden, Plant Breeding and Biotechnology, Swedish University of Agricultural Sciences, Fjälkestadsvägen 459, SE-291 94 Kristianstad, Sweden, and Agriculture-Farming Systems, Technology and Product Quality, Swedish University of Agricultural Sciences,P.O. Box 104, SE-230 53 Alnarp, Sweden