Isozyme procedures for the characterization of germplasm, exemplified by the collection of Lolium perenne L

The utility of isozymes for the characterization of genetic resources is widely recognised and routinely applied to many species. For the Lolium genus a number of different loci and alleles have been identified and used in the characterization of collections and for allied breeding purposes, however confusion has arisen between different sets of results due to the various technical systems applied. Coupled with this is the problem of identification of the products of specific loci and the common designation of alleles at these loci. The present paper provides a synopsis of electrophoretic procedures utilized in a number of European laboratories for the study of Lolium collections together with a nomenclatural code for identifying specific alleles. The origin of this system involved a comparative assessment of a range of tester genotypes of L. perenne L. Seed stocks of these plants are being regenerated and will be maintained at the gene banks of INRA, Clermont Ferrand, France, CPRO-DLO, Wageningen, Netherlands and at AFRC-IGER, Aberystwyth, Wales and are available for reference purposes.