CGN maize collection
The collection originated from the former Foundation for Agricultural Plant Breeding (SVP). The original collection of approximately 1000 accessions was rationalized by excluding hybrids (N=90), inbred lines (N=140) and material received from other genebanks including CIMMYT, Mexico and the Institute for Agrobotany, Tapiószele, Hungary. The maize collection has not a high priority in the CGN system and receives less emphasis in the genetic resources activities. Detailed information on the collection has been published by Van Soest and Boukema (1995).
The collection includes only material of species Zea mays and consists of 487 accessions. Nearly 60% of the accessions are landraces including the 179 accessions collected during the Pakistan expeditions in 1976 and 1981 (Hashmi et al. 1981). This material is unique and probably only duplicated in the genebank at Islamabad, Pakistan. The value of this material for maize cultivation in N.W. Europe is limited, because of its late flowering and subsequent late maturing. The number of cultivars and research material is rather low.
Only five Dutch cultivars; are found in the collection, all of them from before 1960. VC 150 is the only Dutch landrace in the collection. Most likely it originated from an old landrace from the province of Gelderland. Goudster(1952) and Foliant(1953) are developed from inbred lines from the old landrace Van Platte Mais. The 42 landraces from Portugal have been collected in the mountains and were previously used in a breeding programme for cold tolerance. The France landraces are from different localities, mainly of the southern parts of France including the Pyrenees.
Regeneration and characterization
In general each accession is regenerated by collecting ears of at least 100 plants. Seeds are directly drilled in April in the field. During April and May, the maize seedlings are covered with a plastic layer to stimulate early growth. The distance between the rows is 75 cm and after thinning, the plant distance in the row is 25 cm. Pollination is conducted by hand, in general crossings between neighbouring plants. The crossing method used by CGN needs at least 100 crosses per accession. After pollination the ears are wrapped in paper bags. One hunderd ears of each population are collected around October and threshed during the winter. All 487 accessions have been regenerated and are available to potential users. During the growing season and after the harvest the accessions are characterized for a set of 15 agro-morphological traits. For this purpose CGN developed its own minimal descriptor list with advice of private breeding firms in the Netherlands. The collection has not yet been evaluated for pests and diseases or quality traits.
Hashmi, N.I., L.J.M. van Soest, A.R. Rao, M. Mesken and A. Zahoor (1981). Collecting in Baluchistan, Pakistan. Plant Genetic Resources Newsletter 47: 31-35.
Van Soest, L.J.M. en I.W. Boukema (eds.) (1995). Diversiteit in de Nederlandse Genenbank. Een overzicht van de CGN collecties. Centrum voor Genetische Bronnen Nederland (CGN). Centrum voor Plantenveredelings- en Reproduktieonderzoek (CPRO-DLO), Wageningen. 126p.