Before seed of most major agricultural and vegetable varieties can be sold in the EU, the variety must be included on a National List (NL) of a member state or on the Common Catalogue (a compilation of the NLs of the member states). In many countries, particularly in the EU, the controlling legislation complies with the Convention of the International Union for the Protection of New Varieties of Plants (UPOV 1991). The corner stone of the UPOV system is that in order to qualify for protection, a newly bred plant variety has to be shown to be distinct (D), uniform (U) and stable (S). At the moment, the DUS criteria are assessed in the EU member states mainly using a series of replicated field tests and trials. DUS testing takes a minimum of two years and requires considerable resources. Thus, there is much interest in reducing the time, resources, land use and hence cost, of variety registration systems. Although DUS testing currently employs mostly visually observable characteristics that are expressions of the phenotype of a variety, there is much interest in the use of molecular markers. The overall objective of this project is to examine the potential use of molecular markers for the description of genetic variation in ryegrass varieties and to evaluate their possible use in DUS examination. Sixteen reference varieties, four control varieties and one candidate variety were selected for the project. The reference varieties were found to look similar to the candidate variety based on the morphological characterization from the DUS trial. 18 SSR markers were selected based on their genome distribution, reproducibility, level of information and ease of scoring. It was found, that for variety discrimination, reducing the number of SSR markers from 18 SSR markers with 262 alleles to six SSR markers with 140 alleles gives the same level of information. Furthermore, number of genotypes per variety can be reduced to 20 compared to the original dataset containing 60 genotypes when using all 18 SSR markers but not when using only six SSR markers. Significant association was found between the molecular data and the morphological data, indicating that SSR markers can be used for variety identification in ryegrass.
Abstract Book of Plant Biotech Denmark Annual Meeting 2008: Poster 1: Breeding, 2008