CGN pepper collection
The collection
In short- Support for breeding activities
- Maintaining genetic diversitynetische diversiteit
- Part of the fruit vegetables collection
The history of the pepper collection is analog to the other CGN collections of tomato, eggplant, cucumber and melon and described in the general page of the fruit vegetables.
Composition
The CGN pepper collection consists of cultivatedspecies, likeCapsicum annuum, C. chinense,C. frutescens,C. baccatumandC. pubescensand a number of crop wild relatives. The collection with about 1200 accessions, is the fourth largest of Europe. It comprises cultivars, landraces,research material, wild species. Of more than 200 accessions the population type is unknown. C. annuum formsthe largest part of the collection followed by C. chinense and then C. frutescens. Most varieties originate from Europe and the USA. Many landraces originate from Spain and Brazil. In Europe not many accessions of wild species are present in ex situ genebanks, which is also the case for CGN.
The genus Capsicum consists of 40 species. Capsicum species in the CGN collection are diploid and have 24 chromosomes (2n=2x=24). A few non-domesticated species with 2n=2x=26 are known. The part of the genus which is used for cultivation and breeding, can be divided in three complexes:
- annuumcomplex (C. annuum,C. chinense,C. frutescens,C. galapagoense)
- baccatumcomplex (C. baccatum,C. praetermissum,C.tovarii)
- pubescenscomplex (C. pubescens,C. cardenasii,C. eximium)
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 2.5 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 pepper. Exceptions are heterogeneous accessions and outcrossing species like C. cardenasii of which at least ten plants per accession are hand pollinated with a mixture of pollen.
Breeding companies, organized in Plantum NL, assist in the regeneration of pepper. 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. Special attention is given to visual checks and leaf tests for the presence of seed-borne viruses and bacteria (e.g. Tomato Brown Rugose Fruit Virus (ToBRFV)
Karakterisering
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.
Genetic analyses with AFLP, RAPD and ISSR marker systems were used to determine genetic variation and phylogenetic relationships within Capsicum annuum (Kochieva et al. 2004), C. frutescens, C. chinense and C. baccatum (Rhyzhova et al. 2008). The results obtained from these studies have been used to rationalise the collection.
Evaluation
Part of the pepper collection is evaluated for resistance to different strains of Tobamo viruses, Tomato Spotted Wilt Virus (TSWV), Anthracnose (Colletotrichum capsici) and preference of California Thrips (Frankiniella occidentalis), the transmitter of TSWV.
Regeneration of pepper
Seed dormancy
Some wild species germinate much slower (10-30 days) compared to the cultivated species. It is unknown if this is caused by seed dormancy.
Vernalization
None.
Sowing
Before sowing, the 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. As with tomato, after 14 to 30 days the seedlings are transplanted to Rockwool blocks and placed in a greenhouse nursery on tablets at a temperature of 23/20°C day/night and with 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 alternating 60 cm 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.
Generally, 7 plants per accession are used for regeneration. In case of heterogenic accessions, accessions producing few seeds or cross-pollinating wild species (C. cardenasii), up to 10 plants are used. Cross-pollinating wild species are pollinated by hand with a pollen mixture of all plants of an accession. Occasionally, plants are isolated in a gauze cage and pollinated by bumblebees. The number of plants per accession is limited due to the high input of 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, between 5 to 100 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 Aphidius colemani
- 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 on the pepper collection? Ask our curator:
ing. W (Willem) van Dooijeweert
curator fruit vegetables
