Morphological and molecular characterization of Sicilian carob (Ceratonia siliqua L.) accessions

The evergreen carob tree (Ceratonia siliqua) is considered one of the oldest trees in the world, cultivated since ancient times in the Mediterranean Basin, for its edible and high nutritional fruits, adapted to human and animal consumption. Spain is the main producer, followed by Italy, Portugal, Greece, Morocco, and Turkey. In Italy, the cultivation of carob is concentrated in a few provinces and insists on an area of more than 5,500 hectares. In this work 19 accessions, showing interesting fruit traits were analysed morphologically and genetically. Overall, 13 quantitative characters were considered regarding leaf (5 characters), pod (5) and seed (3). To investigate the genetic diversity 8 fluorescently labelled SSR primers were used, indicated as polymorphic in the literature. A UPGMA dendrogram was constructed to depict identity cases and relationships among the accessions. Clustering showed discrimination among accessions from Eastern and Western Sicily. The morphological characterisation does not clearly discriminate any of the cultivars recognized by the growers, similarly, the molecular analysis showed a reduced level of diversity. Since most of these local accessions are of unknown origin and that they are representative of the local germplasm they still warrant protection for their economic and environmental value.