Estimating genetic conformity between related ryegrass (Lolium) varieties.2. AFLP characterization

The concept of genetic conformity lies at the basis of the definition of es sential derivation, or the process of using a protected variety (or 'initia l variety', IV) as the base to develop another similar variety (the essenti ally derived variety, EDV). Methods based on morphology, biochemistry or on molecular markers can be used to estimate genetic conformity. In this stud y, the capability of AFLP(R)(1) markers to provide a reliable and meaningfu l estimate of genetic conformity of different varieties was investigated in diploid perennial ryegrass (Lolium perenne spp.), an allogamous species wh ose varieties are genetically heterogeneous. Twelve accessions with known b reeding lineage, comprising five closely related groups, were included in t he study. For the set of test accessions analysed, the AFLP protocol accura tely reproduced the same relationships as were evident from examining their morphology and both these results were consistent with the relationships k nown to exist within the different test groups. Principal components analys is as well as cluster analysis associated unambiguously the IV and the EDV accessions. It was concluded that the methodology developed in this study c ould be used as a model from which to create a protocol for evaluating puta tive cases of essential derivation.