The collection composition
The eggplant collection of 510 accessions contains mainly cultivated Solanum melongena, but also accessions of other species like Solanum aethiopicum and Solanum macrocarpon, all belonging to the Subgenus Leptostemonum. When material is clustered according crossability , S. melongena and S. incanum belong to the primary genepool, S. aethiopicum, S. anguivi and S. virginianum to the secondairy genepool. S. macrocarpon, S. capsicoides, S. dasyphyllum, S. nigrum, S. scabrum, S. sisymbriifolium, S. torvum, S. viarum and S. villosum can be placed in the tertiary genepool.The collection comprises of 91 cultivars, 316 landraces, 10 research material, 22 accessions of wild species and 71 samples of unknown population type. More than 60% of the collection constitutes of landraces.
Half of the collection is represented by material originating in Asia. About one third are PI numbers received from USDA plant introduction stations. In the period 2002-2005 the African species aethiopicum and macrocarpon from Togo, Nigeria, Ghana, Burkina Faso have been added and enlarged the collection with a substantial part. These accessions have been regenerated in the framework of an EU funded project called “Eggnet”.
EvaluationThe eggplant collection was partly screened for resistance to Fusarium Wilt (Fusarium oxysporum f.sp. melongenae) and Verticillium Wilt (Verticillium spp.) and different strains of Tobamo viruses. Many accessions have been evaluated for bitterness and fruit flesh browning.
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 1.9 g.
Regeneration/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-fertilising eggplant. When samples are heterogeneous, fourteen plants are used.
The Dutch breeding companies assist in the regeneration of eggplant. Some accessions which are difficult to regenerate are put 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.
Regenerations are carried out in close cooperation with breeding companies which are member of the Dutch Association for the Plant Reproduction Material Sector (Plantum NL).
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.