CGN eggplant collection
The collection
In short- Support for breeding activities
- Maintaining genetic diversity
- Part of the fruit vegetables collection
The history of the eggplant collection is analog to the other CGN collections of tomato, pepper, cucumber and melon and described in the general page of the fruit vegetables.
Composition
The eggplant collection of about 500 accessions contains mainly cultivated Solanum melongena, but also accessions of other species like Solanum aethiopicum and Solanum macrocarpon, which all belong to the subgenus Leptostemonum. When the species are clustered according to their crossability with S. melongena, S. melongena and S. incanum belong to the primary genepool, S. aethiopicum, S. anguivi and S. virginianum to the secondairy genepool, and S. macrocarpon, S. capsicoides, S. dasyphyllum, S. nigrum, S. scabrum, S. sisymbriifolium, S. torvum, S. viarum and S. villosum to the tertiary genepool.
The collection comprises of cultivars, landraces, research material, wild species. Of about 70 accessions the population type is unknown. More than 60% of the collection constitutes of landraces.
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. CGN took over the responsibility of part of the former Solanaceae Collection of the Radboud University in Nijmegen, The Netherlands. In future wild species and landraces of this collection will be added.
Maintenance
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, ten 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.
Characterisation
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.
Evaluation
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.
Regeneration of eggplant
Seed dormancy
Some wild species germinate much slower than cultivated species. It is unknown if this is caused by seed dormancy.
Vernalization
None.
Sowing
Before sowing, seeds are disinfected with Na₃PO₄ to avoid infection with Tobacco Mosaic Virus (TMV) and other viruses. Seeds are sown in seed trays with a soil mixture at 25-30°C, generally in January, but it is possible to sow between October and May. After 14 to 30 days, the seedlings are transplanted to Rockwool blocks and placed in a glasshouse nursery on tablets, at a temperature of 23/20°C day/night and additional light.
Planting
About nine weeks after sowing, the plants in the Rockwool blocks are placed on Rockwool bags at a distance of 50 cm in the row and 100 cm between the rows. The distance between rows can differ due to the substrate system used. The temperature in the greenhouse is kept at 23/20°C day/night. The plants are grown along wires. Per plant two stems are maintained (indeterminate types). Plants are pruned once a week. Precautions are taken to prevent virus transmission. The plants are grown in a glasshouse free of pollinating insects. Consequently, it is not necessary to bag the flowers to avoid cross pollination. To enhance pollination and improve seed set, the flowers are touched with a trembling device weekly.
Generally, 7 plants per accession are used for regeneration. In cases of heterogenic accessions, accessions producing few seeds or wild species, up to 14 plants are used. The number of plants per accession is limited due to the high input in labour and capital.
Harvesting
About six months after sowing the fruits are ripe but large variation exists between accessions in flowering time, fruit set and seed production. Per plant 3 to 10 fruits are harvested, depending on the number of seeds per fruit. Fruits are harvested in several rounds when they are ripe and stored for at least a week before seed extraction.
Pest and disease control
Biological control
- Spider mites with Phytoseiulus persimilis
- Thrips with Phytoseiulus persimilis and Orius laevigatus
- White fly with Aphidus coleman
- Aphids with Encarcia formosa
Pesticide treatments
Non-preventive:
- Spider mites, in case biological control is not effective
During regeneration the plants are checked visually for diseases by the Netherlands Inspection Service for Horticulture (Naktuinbouw). In case of doubt, the plants are tested to determine the disease. Infected plants are removed.
Gene bank for plant resources
View the database or submit a request for genetic material.
Do you have a question?
Do you have a question about the eggplant collection? Ask our curator:
ing. W (Willem) van Dooijeweert
curator fruit vegetables
