Olive cultivar identification using nuclear RAPDs and mitochondrial RFLPs

One hundred and thirteen olive accessions obtained from different collections and various orchards around the Mediterranean Basin were characterised using RAPD-PCR. The polymorphic bands obtained using a combination of only three RAPD primers enabled us to distinguish between one hundred and two of the accessions. We estimate that the probability of obtaining the same RAPD profile for two different trees was between 6.75 x 10(-5) and 4.82 x 10(-14.). Many of the RAPD profiles were correlated with the country or region of origin of the accessions, suggesting that cultivar selection occurred within different genetic pools and within different areas. Furthermore, RFLP analysis of mitochondrial DNA revealed four mitotypes. Mitotype ME1 (72 %) was by far more frequent than mitotypes ME2 (10 %), MOM (9 %) and MCK (9 %). Accessions that were genetically similar, based on the RAPD analysis, occurred in either the eastern (ME1 or ME2) or the western (MOM or MCK) group of the Mediterranean. This finding suggests that nuclear and cytoplasmic DNAs have been combined due to crosses between trees from different origins.