Molecular markers in olive: an integrated approach

The use of molecular markers in olive selection and breeding program, from cultivar identification to mapping, is described in this paper. All the molecular markers used in the Germplasm Bank of Córdoba (isozymes, RAPDs and SSRs) have shown to be useful for identification purposes. Five enzymatic systems have made possible the identification of 132 olive cultivars, while 215 cultivars were reliably discriminated by the combination of six RAPD primers. Two hundred and sixty-four genotypes (80% of all the cultivars included in the germplasm bank) were analyzed and identified by means of five SSR markers. Using this information, a plant certification unit has been established at the Department of Agronomy at University of Córdoba. SSRs were also used to evaluate the material obtained from collecting expeditions of centennial olive trees in Andalusia. Associations between the varieties and their geographical diffusion have been observed in all the olive areas studied by means of molecular markers. The transferability of olive microsatellite across the genus Olea and their reliability for intra-species variability evaluation has been confirmed. On the other hand, paternity of olive progenies obtained from the breeding program of the University of Córdoba has been successfully checked by only four SSR primer pairs selected for this purpose. This has contributed to improve the pollination method. RAPD, AFLP and SSR markers have been employed to develop the first linkeage map in olive.