Morphometric and Molecular Analysis of the Three Arbutus Species of Greece

Arbutus andrachne, A. undo and A. x andrachnoides found in the Greek macchia are promising species for reforestations, ornamental use, as well as for medicinal use and the food industry. Morphological traits and molecular markers (RAPD) were used to identify and distinguish these Arbutus species to facilitate their exploitation. Since there are no descriptors established for Arbutus spp., 23 qualitative morphological characteristics of crown, foliage, bark, flowering, fruiting, and four quantitative morphological characteristics of leaf and fruit were selected and used to define differences and similarities between sampled individuals of A. andrachne, A. undo and individuals with intermediate characteristics sampled as A. x andrachnoides. Twenty eight individuals representative of three Arbutus taxa were sampled in two typical macchia forest areas of the prefecture of Attica, Greece. Cluster analysis based on morphological characteristics separated the individuals in three distinct groups, and this was confirmed by molecular analysis. The intermediate form was indicated as A. x andrachnoides, a natural hybrid of A. andrachne and A. unedo. Fifteen 10-mer oligonucleotide arbitrary primers used to amplify genomic DNA generated 166 reproducible polymorphic fragments, which revealed that A. x andrachnoides has higher degree of genetic similarity with A. andrachne than A. unedo. The applied morphometric characteristics are suggested as a basis to develop a complete list of discriminating descriptors for Arbutus genus.