Genetic diversity on Pyrus L. (Rosaceae) in Sicily

The genetic diversity on six Pyrus species (P. amygdaliformis, P. pyraster, P. communis, P. vallis- demonis, P. sicanorum, P. castribonensis) from Sicily was investigated using isozymes. Atotal of 26 alleles was found in 8 loci of 5 enzyme systems (IDH,MDH, 6-PGD, PGI and SKD). The allelic frequencies and the genetic variability values for each population were calculated. The greatest rate of polymorphism was found in P. sicanorum, P. castribonensis and P. amygdaliformis from Sicani Mts. The relationships among the populations were computed by Nei’s genetic identity/distance and the obtained dendrogram shows a remarkable genetic distance of P. vallis-demonis from of all other investigated taxa; P. sicanorum appeared enough distinguished; the other examined taxa formed a clade in which P. castribonensis and P. amygdaliformis, resulted more similar than P. communis and P. pyraster.