Optimal use of RAPD markers for identifying varieties in olive (Olea europaea L.) germplasm collections

The aim of this work was to study in depth the resolving power of RAPD markers for rapid and reliable identification of olive cultivars in germplasm collections. The D parameter (the probability that two randomly chosen cultivars have different banding patterns), used for that purpose, showed high values for most of the 21 primers tested and its values ranged from 0.6114 (OPI-13) to 0.9762 (OPK-16) with a mean value of 0.8566. This parameter was used to select the five most discriminating primers: OPK-16, OPA-19, OPX-09, OPF-06 and OPZ-11. The joint confusion probability and the statistical number of indistinguishable pairs of cultivars were estimated for these primers (under independence hypothesis). The combination of three primers (OPK-16, OPA-19 and OPX-09) was found optimal for rapid discrimination of 103 cultivars with a very low value of cumulative confusion probability (1.72 x 10(-5)), leaving 0.09 pairs of cultivars indistinguishable. This fact, together with the efficiency of the most discriminating primers combination on an increasing number of cultivars, evidenced the utility of RAPD markers for discrimination of olive cultivars in collections and in nurseries.