Analysis of diversity in the fruit tree genetic resources from a Mediterranean island

A large number of genotypes of different fruit tree species have been described in Sardinia, where the plant species have evolved by adaptation to the Mediterranean environment. In this work results are summarized of a long-term survey carried out in the island by the authors since the early 1980s. Ten fruit tree species have been surveyed and collections of the traditional varieties were established. Some are major staple crops such as olive and grape, others such as almond, cherry, plum, fig, apple and pear are nowadays less cultivated, and still others have been more recently introduced like apricot and cactus pear. Data on the level of inter and intra-species diversity are given, as illustrated by representative morphological traits. The results of isozymes and RAPD-PCR analysis on the species Ficus carica genotypes are included, to assess genetic relationship among accessions. Observations on composition, as well as on state of conservation of selected traditional varieties are reported, and the main causes of genetic erosion are listed