CGN pepper collection

Composition

The CGN pepper collection consists of cultivated species, like Capsicum annuum, C. chinense, C. frutescens, C. baccatum and C. pubescens and a number of crop wild relatives. The collection with 1141 accessions, is the fourth largest of Europe. It comprises 519 cultivars, 308 landraces, 20 accessions of research material, 60 accessions of wild species and 234 accessions of unknown population type. C. annuum (N=898) forms the largest part of the collection followed by C. chinense (N=119) and C. frutescens (N=49). Most varieties originate from Europe and the USA. About half of the landraces originate from Spain and Brazil. In European genebanks not many accessions of wild species are present in ex situ genebanks, which is also the case for CGN. In most genebanks in South America a few accessions of wild species are present.

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=32 are known. The part of the genus which is used for cultivation and breeding, can be divided in three complexes:

• annuum complex (C. annuum, C. chinense, C. frutescens, C. galapagoense)

• baccatum complex (C. baccatum, C. praetermissum, C.tovarii)
• pubescens complex (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. When samples are heterogeneous, fourteen plants are used.

Breeding companies, organised 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.

Characterisation

Characterisation 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 characterised 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 characterisation 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.