CGN cereals collection

Additional material was obtained from other, mainly Dutch, institutions and private breeding companies. The three cereal collections receive nowadays less emphasis in the genetic resources activities of CGN as the focus of CGN since 2005 is on vegetables. Detailed information on the cereal collections have been published by (Van Soest and Boukema 1995). In 2010-2011 a search has been carried out to identify accessions which originally had been received from collections of IPK, Gatersleben and USDA National Germplasm System. The respective curators have been consulted and the assurance was given that the duplicated accessions are being maintained and are available from their collections. In 2011 a total of 1620 accessions of Triticum, Hordeum and Avena (N=742, 848 and 140 respectively) have been removed from the CGN cereals collection and are being stored as  archive collection at -20 °C.

Since the collections have been established, the seed for germplasm exchange has been stored at + 4 °C. Around 2012 a few users complained that the germination of some of this material had dropped considerably. In order to determine the extent of the problem, tests have been carried out on wheat and barley material regenerated in different years. The results have been published in a paper by Van Treuren et al. (2018). Rapid loss of seed viability in ex situ conserved wheat and barley at 4 °C as compared to –20 °C storage. The conclusion was that the viability of the seed stored in 4 °C before 1990 had dropped significantly, particularly the wheat material. CGN took the measure to also store all user material from the small grains collections in deep freezers. Above this, seed of wheat accessions, stored at 4 °C before 1990 has been replaced with seed stored at -20 °C.

Regeneration and characterization

Most of the material included in the small grain cereal collections has been regenerated and is stored under long term storage conditions (-20°C) in the genebank facilities of CGN. Regeneration of a large part of the collection took place between 1986 and 1992, partly in cooperation with private cereal breeding firms in the Netherlands.

The winter types are sown in October and the spring types in March at a density of 350 seeds per m² in plots of 1.25 m² and 25 cm row distance. The seeds are harvested with a special combine or by hand. During the regeneration the cultivated accessions are characterized for a minimal set of agro-morphological traits using descriptor lists developed by CGN (Koch 1985, Loosdrecht 1985). The wild cereals are regenerated in the greenhouse. The winter types are vernalized as seedlings in a cold greenhouse at < 10 °C for at least six weeks. During flowering, the ears are covered by perforated polythene bags in order to collect the seeds which scatter as soon as they are ripe.

Evaluation data are available of screenings for resistance to some important cereal diseases such as Erysiphe graminis (Blumeria graminis) (wheat and barley), Puccinia hordei (barley), Puccinia striiformis (wheat), Rhynchosporium secalis (barley), Pyrenophora ssp. (barley), Mycosphaerella graminicola (wheat) and Puccinia triticina (wheat).

Triticum and Avena accessions from the collection have been analysed in studies in the framework of the Celiac Disease Consortium. (Herpen et al. 2006, Salentijn et al. 2009, Broeck et al. 2010, Mujico et al. 2011).