Phenotypic characterization and evaluation of European cherry collections: A survey to determine the most commonly used descriptors
Standardization of descriptors and protocols is a precondition when aiming to harmonize characterization data records from different plant collections. Improved information on the accessions maintained at the European collections has been a priority target of the Prunus Working Group (WG) of the European Cooperative Programme for Genetic Resources network (ECPGR) since its establishment in 1983. Recently, in order to prioritize in the characterization of the Prunus spp. accessions, the Prunus WG began selecting a subset of descriptors (First Priority Descriptors, FPD) considered most informative, from the crop-specific descriptors published by International organizations such as Bioversity International (formerly IPGRI)  and UPOV (International Union for the Protection of New Varieties of Plants) . In 2013, a survey was carried out among the cherry collection holders, in the framework of the COST Action FA1104 'Sustainable production of high-quality cherries for the European market', to ascertain which descriptors, categories and scales were most in use for the evaluation and characterization of cherry cultivars in Europe . Sixteen descriptors were routinely used by at least two-thirds of respondents (15 descriptors for sweet and 14 for sour/duke cherry), and deemed most effective in describing cherry accessions, based on the answers provided by 22 sweet cherry and 13 sour/duke cherry curators. This list of most used descriptors, relating to the phenology of blooming and harvesting, tree habit and vigor, fruit size, morphology and internal quality, are now under consideration by the Prunus WG for inclusion in the FPD list recommended for the characterization of the ECPGR cherry resources.