CGN onion and leek collection
The Allium collection originates from the former Institute for Horticultural Plant Breeding (IVT).The IVT collection existed mainly of onion and leek cultivars collected at Dutch seed firms in the framework of the European Cooperative Programme for Crop Genetic Resources Networks (Van der Meer and Van Bennekom 1983). After adopting this collection, much attention was given to rationalise the collection by bulking duplicates both from onion and leek. This effort resulted in a considerable reduction of the collection (Boukema and De Groot 1991).
The collection was expanded with material collected in a multicrop expedition in Pakistan (Hasmi et al. 1981), material collected in Bulgaria, accessions from multicrop expeditions funded by IPGRI in Egypt, from collecting missions in the framework of the German-Dutch cooperation in Plant Genetic Resources to Turkey, Russia (Daghestan), Armenia and Georgia, from a multicrop collecting expedition to Uzbekistan (Van Soest et al. 1998) and from a collecting mission to Greece in 2009 (Kik 2009), the latter collection being part of the Special Collection of CGN.
The collection was completed with missing prominent open pollinated Dutch and European varieties and with material from the working collection of the CPRO-DLO. Wild material was also introduced from botanical gardens and from other genebanks. CGN takes actively part in the Allium network of the European Cooperative Programme for Crop Genetic Resources Networks. The passport data of the CGN Allium collection are included in EURISCO and GENESYS. CGN gives high priority to the Allium collection and aims to create a representative sample of the total genetic diversity in onion and leek and its wild relatives in cooperation with other European genebanks. For a recent overview on global Allium genetic resources (Keller and Kik 2018).
The collection includes presently 431 accessions of seed propagated Allium's. The onion collection consists mainly of varieties from the Netherlands and Japan. Also landraces from Egypt, Bulgaria, Russia, Pakistan and Uzbekistan are present in the collection and a few wild relatives among which A. roylei. The bunching onions are nearly all varieties from Japan. The leek collection consists of cultivars from the Netherlands, France and Denmark, landraces from Bulgaria, and wild relatives of the ampeloprasum complex from Greece. The kurrat's are landraces originating from Egypt. The Chinese chives are landraces from Thailand and Australia.
Constraints in regeneration are faced in case of short-day material, in particular material from Pakistan. Also regeneration of wild material causes sometimes difficulties. It can take several years before enough seed is produced to fulfil the CGN standards. For the regeneration of an accession 60-120 plants are used. After onion bulbs have been harvested, dried and potted, they are placed in a non-heated glasshouse for overwintering. Because of problems with Fusarium attack, seedlings of leek are planted directly in pots and overwintered from November onwards in a glasshouse at 5-10°C. As soon as flowers appear, the plants are transferred to isolation rooms and pollinated by blowflies.
Characterization and evaluation
Most of the Allium collection has been characterized for 15-20 traits, using descriptorlists developed by CGN (partly derived from UPOV and ECPGR descriptor lists). Cultivars are characterized during bulb/mature plant production for regeneration. Evaluation data on characters such as diseases are obtained in close cooperation with users of the material. Data on resistance to Peronospora destructor, Sclerotinium cepiforum, Botrytis aclada, B. squamosa, Puccinia porri and Thrips tabaci are available.
Boukema, I.W. & E.C. de Groot, 1991. Reduction of redundancy in the CGN Allium collection. Allium Improvement Newsletter 1: 25-26.
Gass, T. D. Astley, H.D. Rabinowitch and E.A. Frison, compilers, 1996. Report of a Working Group on Allium. Fifth meeting, 25-27 May 1995, Skierniewice, Poland. International Plant Genetic Resources Institute, Rome, Italy.
Hasmi, N.I., L.J.M. van Soest, A.R. Rao, M. Mesken and Zahoor Amad, 1981. Collecting in Baluchistan, Pakistan. Plant Genetic Resources Newsletter 47: 31-35.
Meer, Q.P. van der & J.L.van Bennekom, 1983. Collection of Onion- and Leek genotypes in the Netherlands. Internal IVT report, Wageningen.
Soest, L.J.M. van, K.I. Baimatov, V.F. Chapurin & A.P. Pimakhov, 1998. Multicrop collecting mission to Uzbekistan. Plant Genetic Recources Newsletter 116: 32-35.
Keller, E.R.J. & C. Kik (2018). Allium genetic resources. In: M. Shigyo, M Abdelrahman & A Khar (Eds.). The Allium genomes. Springer Nature, Cham, Switzerland. pp. 23-52. Kik C. (2009).
Report of a leek (Allium porrum) wild relatives collecting expedition in Greece. CGN report 15. CGN, Wageningen, the Netherlands. pp.17.