TAXONOMIC POSITION AND ORIGIN OF THE ENDEMIC SICILIAN FIR ABIES NEBRODENSIS (LOJAC.) MATTE1 BASED ON ALLOZYME ANALYSIS

Abies nebrodensis (Lojac.) Mattei (Sicilian fir) is a forest tree species endemic to the mountainous regions of northern Sicily (the Madonie Range) that is currently represented by just one population of 29 individuals. The major questions relating to this species are its unknown origin and its uncertain taxonomic position. According to many authors A. nebrodensis is morphologically intermediate between the neighboring Mediterranean Abies species: Abies alba (Mill.) (silver fir), Abies numidica (De Lann) (Algerian fir) and Abies ceplzalonica (Loud.) (Greek fir). In the present study we analyzed eight enzyme systems in the population of A. nebrodensis and in seven populations from A. alba, A. cephalonica and A. numidica. The aim was to clarify the taxonomic position and origin of A. nebrodensis. High values of expected heterozygosity and number of polymorphic loci were found in A. cephalonica, while A. alba and A, nebrodensis showed intermediate levels of polymorphism and A. numidica was the least variable species. All values were similar to those found in other conifers. The relatively high level of diversity found in A. nebrodensis confirms that despite the extremely small population size, the few individuals left in this species still retain a considerable amount of the original genetic variation at the nuclear level. Results also showed tha