DUPLICATION WITHIN AND BETWEEN GERMPLASM COLLECTIONS .2. DUPLICATION IN 4 EUROPEAN BARLEY COLLECTIONS

The extent of duplication within and between barley genebank collectio ns has been determined from a comparative analysis of four European ba rley collections. These collections were those of the Centre for Genet ic Resources, the Netherlands, the Institute of Plant Genetics and Cro p Plant Research and the Braunschweig Genetic Resources Centre, both i n Germany, and finally that of the John Innes Institute in the United Kingdom. These collections comprise over thirty thousand accessions. A random set of 100 accessions from the CGN barley collections was matc hed with all four collections to identify probable duplication, result ing in 61% of the accessions being matched. Passport data were used to identify probable duplicates. This was hindered by the low quality of these data; simple perfect matches were rare. The probable duplicatio n, excluding parental duplication, involved 144 other accessions. Usin g seed traits, field observations and electrophoretic markers, it coul d be shown that more than three quarters of the matched accessions in the random set, excluding parental duplication, were completely duplic ated in the others and one fifth were more or less duplicated in other matched accessions. If individual comparisons between accessions from the random set and the matched accessions were made, about one fifth of the probable duplicates were shown not to be duplicates at all. One half were identical duplicates, and the rest were common or partial d uplicates.