The history of the cucumber collection is analog to the CGN collections of tomato, pepper, eggplant and melon and described in the general page of the fruit vegetables.
The cucumber collection of CGN is only composed of the cultivated Cucumis sativus and holds currently 925 accessions. A few accessions of the subspecies C. sativus var. hardwickii and C. sativus var. sikkimensis are present. It is one of the largest collections in Europe and comprises of 371 cultivars, 137 landraces, 16 accessions of research material, 4 accessions of C. sativus var. hardwickii which is considered to be the wild form and 397 accessions of unknown population type which will be improved when more information is available. A diversity study with molecular markers revealed that the landraces are genetically clustering apart from the rest of the collection (Ly et al. 2012). A quarter of the collection are cultivars originating from Europe of which 154 Dutch accessions. Unique landraces have been collected in Egypt, Pakistan, Kyrgyzstan and Uzbekistan.
To be incorporated in the collection, accessions need to have a minimum seed viability of 80% for cultivated material and 60% for accessions of wild species. Regeneration is carried out when seed viability is to low or when the remaining seed quantity has dropped below 12.5 g. Regeneration/multiplication takes place in insect-free glasshouses on a substrate system where the stems are grown along ropes.