Molecular Characterization and Analysis of the Greek Citrus Germplasm

Molecular markers were used to evaluate genetic similarity among 36 citrus accessionsc (C. sinensis, C. reticulata, C. limon and cultivars) of the Greek national clonal germplasm repository located in Poros. In total, nine RAPD and five ISSR primers produced 262 loci, of which 236 were polymorphic. Both techniques were proven to be equally analytical with an average discrimination power above 0.9. The RAPD and ISSR markers were highly correlated and clustering among them had high correspondence. Citrus accessions formed separate clusters according to their species, even though sweet orange and mandarin cultivars revealed high affinity, while lemons were more divergent. C. sinensis genotypes had the highest intragenetic affinity suggesting that cultivated oranges have a narrow genetic base. On the contrary, the C. reticulata group was the most variable. In general, Greek varieties exhibited a distinctive genetic background that could be discriminated from foreign established cultivars using the mentioned molecular techniques. This information could facilitate their use in future Citrus spp. breeding programs.