Polymorphism and Discrimination Capacity of Randomly Amplified Polymorphic Markers in an Olive Germplasm Bank

Abstract

Random amplified polymorphic DNA (RAPD) analysis was performed on the main Mediterranean cultivars of olive (Olea europaea L.) from the Germplasm Bank of the Centro de Investigación y Formación Agraria “Alameda del Obispo” in Cordoba, Spain. One hundred and ninety reproducible amplification fragments were identified using 46 random primers followed by agarose gel electrophoresis. Some 63.2% of the amplification products were polymorphic, with an average of 2.6 RAPD markers obtained for each primer. The combination of polymorphic markers resulted in 244 banding patterns. The high degree of polymorphism detected made identification of all the cultivars (51) possible by combining the RAPD banding patterns of just only four primers: OPA-01, OPK-08, OPX-01, and OPX-03. Cultivar-specific RAPD markers and banding patterns were also found. A dendrogram based on unweighted pair-group method cluster analysis was constructed using a similarity matrix derived from the RAPD amplification products generated by the 46 primers. Three major groups of cultivars could be distinguished by RAPD analysis: 1) cultivars from east and northeast Spain, 2) Turkish, Syrian, and Tunisian cultivars, and 3) the majority of common olive cultivars in Spain. The dendrogram thus showed a good correlation between the banding patterns of olive cultivars and their geographic origin. A higher level of polymorphism was observed when polyacrylamide gel electrophoresis was used to separate the amplification products. Thus, adequate use of RAPD technology offers a valuable tool to distinguish between olive cultivars.