The collection of melon is small. It contains only accessions which could not be found in other collections; 17 accessions originate from the Netherlands. Part of the collection comes from the former IVT and about 30 accessions were collected during an IPGRI collection mission in Pakistan in 1981. In 2017 a collecting expedition took place in Uzbekistan which resulted in an additional 62 landraces which could be added to the collection. This resulted in a total of 141 accessions (March 2020) of which 79 accessions are presently available because regeneration is needed to meet CGN standards. The available collection comprises of 23 cultivars, 42 landraces mostly from Pakistan and Egypt and 14 accessions of unknown population type. Melon comes in many different types and can be sweet to sour.
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. For melon, which is a cross-fertilizing species, ten plants are used. When samples are heterogeneous, fourteen plants are used. Breeding companies, organized in Plantum NL, assist in the regeneration of melon. Accessions which are difficult to regenerate are placed in isolation cages with bumble bees for pollination. During the growing season plants are monitored by the Dutch Plant Health Service for seed borne diseases in order to prevent seed contamination.
Characterization of fruit vegetables takes place during regeneration. Almost all accessions have been morphologically described. Melon is characterized by minimum descriptors developed by the ECPGR Working Group. The minimum descriptor lists consist of about ten descriptors and can be found at the ECPGR Cucurbits webpage. All characterization data are made available on-line and in downloadable files.
The collections are well photo-documented, many pictures of (un)ripe fruits, plant and flowers are available. When necessary new pictures will be taken during regeneration and added to the CGN website.
About 18 accessions of the collection were genotyped by sequencing in 2014 as part of the “100 melon genomes project”.