Half of the collection has an Asian origin. About one third are PI numbers received from USDA plant introduction stations. In the period 2002-2005 the African species S. aethiopicum and S. macrocarpon from Togo, Nigeria, Ghana, Burkina Faso have been added and enlarged the collection substantially. These accessions were formerly held by R. Lester of the University of Birmingham, but during the EU funded project “Eggnet”, the accessions were transferred to CGN and the Radboud University Nijmegen, the Netherlands and to INRA Montfavet, France.
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 too low or when the remaining seed quantity has dropped below 1.9 g. Regeneration and multiplication takes place in insect-free glasshouses on a substrate system where the stems are grown along ropes. Seven plants are used to regenerate self-fertilizing eggplant. When samples are heterogeneous, fourteen plants are used.
The breeding companies, organized in Plantum NL, assist in the regeneration of eggplant. Accessions which are difficult to regenerate are transferred to 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. Until 2006 about 30 descriptors were used for each crop. Since 2006 the fruit vegetables are characterized by minimum descriptors developed by the ECPGR Working Groups. The minimum descriptor lists consist of about ten descriptors per crop and can be found at the ECPGR Solanacaeae 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.
The eggplant collection was partly screened for resistance to Fusarium Wilt (Fusarium oxysporum f.sp. melongenae) and Verticillium Wilt (Verticillium spp.). Many accessions have been evaluated for bitterness and fruit flesh browning.