The crucifer collection exists of more than 40 crop groups. The collection originates from the former Foundation for Plant Breeding (SVP), the Institute for Horticultural Plant Breeding (IVT) and departments of Wageningen Agricultural University (WAU, now part of Wageningen University and Research Centre).
Part of the material was collected in the Netherlands in the framework of the EU project "The collection of landraces of Cruciferous crops in the EC countries" (van der Meer et al. 1984).
Presently, the CGN collection of cruciferous crops includes 1750 accessions. The collection contains mainly cultivars (1080), furthermore landraces (294) and research material (181). Only 14 accessions are documented as wild populations and of 181 accessions the population type is not known. B. oleracea is represented with the highest number of accessions followed by B. rapa, Raphanus sativus, B. napus and B. carinata.
CGN developed the European Brassica Database (Bras-EDB) in the framework of the Brassica Working Group of the European Cooperative Programme for Crop Genetic Resources Networks (ECP/GR, Maggioni et al. 1997). The ECPGR Brassica database contains passport data of most of the European Brassica collections and is updated regularly. (van Hintum & Boukema, 1993, Boukema & van Hintum, 1998, Bas, 2009)..
CGN coordinated a European project on Brassica: "Brassica Collections for Broadening Agricultural Use" including "Characterising and utilising genetic variation in Brassica carinata for its exploitation as an oilseed crop" (RESGEN CT 99 109-112). This project deals with characterisation, evaluation, regeneration and documentation of B. napus, B. oleracea, B. rapa and B. carinata. Results of this project are downloadable via the BrasEDB website.
The Brassica oleracea collection
CGN gives high priority to the B. oleracea collection and aims to create a representative sample of the total genetic diversity in this crop in cooperation with other European genebanks in the Brassica network of the ECPGR.
With the help of the Bras-EDB a core collection of B. oleracea was developed (Boukema et al. 1997) for an EU project entitled "The location and exploitation of genes for pest and disease resistance in European genebank collections of horticultural Brassicas" (Leckie et al. 1996). A more balanced core, including more European Brassica collections, has been developed in the EU-project RESGEN CT 99 109-112.
Much attention has been given to rationalize the B. oleracea collection by bulking duplicates into groups. The bulked accessions concerned selections of the same 'umbrella' varieties which were regarded as duplicates on the basis of their historical background and morphological resemblance in the field. Crop specialists advised in this activity. This effort resulted in a considerable reduction of the collection. A genetic analysis on the basis of electrophoresis of isoenzymes of part of the rationalized material justified the procedure (van Hintum et al., 1996). In a further study, using AFLP’s, while taking into consideration the changes over regenerations, it was concluded that accessions which display similar levels of differentiation may be combined safely (van Hintum et al, 2007).
Hybrids are not included in the collection and wild species are only represented with very low numbers. The B. oleracea collection gives a good representation of the old Dutch open pollinated varieties and Danish material is also well represented. Egyptian landraces are included in the cauliflower and white cabbage collections. The white cabbages include also material from the former Soviet Union. The Chinese kale's originate mostly from Thailand and Taiwan. In the B. oleracea collection cauliflower is represented with the highest numbers. In this crop almost no rationalization has taken place because the accessions are morphological rather distinct.
The B. rapa collection is a very diverse collection including vegetable, fodder and oilseed crops. Although most material involves varieties from Europe, part of the vegetables originates form Asia. A large part of the B. rapa collection has been used in a study assessing the genetic diversity between the different croptypes (Zhao et al, 2005, 2007). The B. napus collection represents, besides oilseed, also fodder types and includes mainly varieties from Europe. The B. carinata and B. nigra collections represent mainly Ethiopean landraces and the B. juncea collection includes both oilseed and vegetable crops. The Raphanus collection includes mainly radish cultivars from Europe and giant radish from Asia. The fodder radish originates mainly from the former Soviet Union, the Netherlands and Germany. The Sinapis alba collection is predominantly of European origin.
For regeneration 60-120 plants are used. All crucifers are regenerated in isolated plots or in cages in glasshouse compartments. Most of the B. oleracea crops are biennial and need vernalisation. In general the B. oleracea material is planted in the field. The vegetative mature plants are potted in autumn and placed for overwintering in a glasshouse at 5-10°C. This gives the possibility to do some negative selection against off-types. Before overwintering the cabbages are decapitated. From early cabbages cuttings are made from shoots after decapitation in the field and the resulting plants overwinter. As soon as flowers appear, the plants are transferred to cages and pollinated by blowflies (Dotinga et al. 1988) or bumble bees. Another method is 'stullenteelt' which is performed on not-mature plants, gronw in pots. The plants must have at least 7 leaves when they are overwintered in a greenhouse between 5-10°C. This vernalization method can only be used when no selection needs to take place of plants contributing to the regeneration of the accession. Dutch breeding companies assist in the regeneration work.
The field crops of the crucifer collection are regenerated in spatially isolated fields in winter rye or Triticale. More information can be found in the "Approach – Regeneration" section of this website.
Characterization and evaluation
Parts of the collection have been characterized and evaluated for more than 70 traits. Most of the B. oleracea material has been characterized for morphological traits, according to CGN descriptor lists, partly derived from UPOV and ECPGR descriptor lists (IBPGR 1990). Also part of the radish and vegetable turnip collection as been characterized. Evaluation data on characters such as disease resistance are obtained from users of the material. Parts of the collection were screened in the framework of two EU projects for resistances to different pests and diseases, glucosinolates and seedstorage components. More information, results and literature from these projects can be found at the BrasEDB website. Data on resistance in part of the B. oleracea collection to Fusarium oxysporum, Plasmodiophora brassicae and Thrips tabaci are also available. Phosphate and phytate content has been assessed for more than 130 B. rapa accessions (Zhao 2007). Part of the B. napus collection was screened for resistance to Heterodera schachtii and for cadmium uptake. Part of the B. nigra collection was screened for resistance to Phoma lingam. Of the B. carinata collection the fatty acid composition was determined by Mahler and Auld (1988).
Bas, N. and F. Menting (2009) The European Brassica Database: updates in 2005 and 2007. In Report of a Vegetables Network. Second Meeting, 26–28 June 2007, Olomouc, Czech Republic. Bioversity International, Rome, Italy.
Boukema, I.W., Th.J.L. van Hintum & D. Astley (1997) The creation and composition of the Brassica oleracea Core Collection. Plant Genetic Resources Newsletter 111: 29 -32.
Boukema, I.W., & Th.J.L. van Hintum (1998) The European Brassica Database. Proceedings of an International Symposium on Brassicas. Acta Horticulturae 459. ISHS 1998. pp 249-254.
Boukema, I.W., & Th.J.L. van Hintum (1999) Genetic Resources. In: C. Gómez-Campo (ed) Biology of Brassica Coenospecies. Elsevier Science B.V., Amsterdam. pp 461-479.
Centre for Genetic Resources, the Netherlands( 2006) Kool in Nederland, geschiedenis van teelt en veredeling, WUR-brochure.
Dotinga, F.D., I.W. Boukema & E.C. de Groot (1988) Pollination of cole crops by honey bees or blow flies? Cruciferae Newsletter 1988: 132-133.
Hintum, Th.J.L. van & I.W. Boukema (1993) The establishment of the European Database for Brassica. FAO/IBPGR Plant Genetic Resources Newsletter no 94/95: 11-13.
Hintum, Th.J.L. van, I.W. Boukema & D.L. Visser (1996). Reduction of duplication in a Brassica oleracea germplasm collection. Grace: 343-349.
Hintum, Th. J. L. van, C. C. M. van de Wiel , D. L. Visser, R. van Treuren, B. Vosman (2007) The distribution of genetic diversity in a Brassica oleracea genebank collection related to the effects on diversity of regeneration, as measured with AFLPs. Theor. Appl. Genet. 114:777–786
IBPGR (1990) Descriptors for Brassica and Raphanus. International Board for Plant Genetic Resources, Rome.
Leckie, D., D. Astley, I.R. Crute, P.R. Ellis, D.A.C. Pink, I. Boukema, A.A. Monteiro, S. Dias (1996) The location and exploitation of genes for pest and disease resistance in European gene bank collections of horticultural Brassicas. Acta Hort. 407, 95-101..
Maggioni, L., D. Astley, M. Gustafsson & T. Gass, compilers (1997) Report of a Working Group on Brassica, Third meeting, 27-29 November 1996, Rome, Italy. International Plant Genetic Resources Institute, Rome.
Mahler, K.A. & D.L. Auld (1988) Fatty acid composition of 2100 accessions of Brassica. University of Idaho, Moscow, Idaho, USA. 173p.
Meer, Q.P. van der, H. Toxopeus, P. Crisp, H. Roelofsen & D. Astley (1984) The collection of land-races of Cruciferous crops in the EC countries. Final report of the EC research programme 0890. IVT, Wageningen. 209p.
Soest, L.J.M. van & I.W. Boukema (eds.) (1995) Diversiteit in de Nederlandse genenbank. Een overzicht van de CGN collecties. Centrum voor Genetische Bronnen Nederland (CGN). Centrum voor Plantenveredeling en Reproductieonderzoek (CPRO-DLO), Wageningen. 126p.
Zhao, J., X. Wang, B. Deng, P. Lou, J. Wu, R. Sun, Z. Xu, J. Vromans, M. Koornneef, G. Bonnema (2005) Genetic relationships within Brassica rapa as inferred from AFLP fingerprints. Theor. Appl. Gene.t 110: 1301–1314
Zhao, J., M.J. Paulo,D. Jamar,., P. Lou,, F. van Eeuwijk,, G. Bonnema (2007). Association mapping of leaf traits, flowering time, and phytate content in Brassica rapa. Genome, 50(10): 963–973.