The following 16 Aegilops species, with a total of 191 accessions, are included in the wheat collection: A. triuncialis, A. peregrina, A. columnaris, A. biuncialis, A. necglecta, A. geniculata, A. cylindrica, A. cuadata, A. bicornis, A. longissima, A. speltoides, A. tauschii, A. crassa, A. ventricosa. With exception of some tetraploids, the majority of these species is diploid. A large part (N=257) of the accessions is wild emmer, Triticum turgidum var. dicoccoides, mainly collected in Israel.
The cultivated group comprises material of T. monococcum, the T. turgidum group, T. timopheevii var.timopheevii and the T. aestivum group. The latter group includes the hexaploid spelta, compactum, sphaeroccocum and aestivum wheats, whereas the durum, dicoccon, carthlicum, turgidum and polonicum wheats belong to the tetraploid T. turgidum group. Most cultivated wheats of the collection belong to the T. aestivum group, particularly to the T. aestivum group aestivum. This group includes 2009 accessions of spring wheat, 104 intermediate types and 1885 winter wheats. Approximately half of this material is of European and North American origin, particularly the cultivars, but also a substantial number of research material and landraces. The European landraces are predominantly from East, South and Central Europe.
Only three old Dutch winter wheat landraces are present in the collection namely Zeeuwse witte, Limburgse Kleine Rode, and Gelderse Ris. The Institute of Plant Breeding in Wageningen and R.J. Mansholt in Groningen bred the first Dutch wheat varieties and around 30 varieties from these breeders are included. The T. aestivum group aestivum also includes accessions from Asia and Africa. Of these accessions, 90% are landraces collected between 1953 and 1981 in the centres of diversity (Middle East, Nepal, Pakistan, India, N.Africa and Ethiopia). Only a limited number of accessions are from South America, Australia and New Zealand.
The tetraploid T. turgidum group consists for nearly 60% of 'durum' wheats, mainly landraces from Mediterranean countries. In this group also 62 cultivated spring and winter Emmer wheats are included.