Genetic Diversity of Dalmatian Sage (Salvia officinalis L.)

Dalmatian sage (Salvia officinalis L.) is a perennial subshrub belonging to Lamiaceae family. It is a native of the northern shore region of the Mediterranean, and grows wild in large masses in the calcereous, karstic mountains of Dalmatia, Herzegovina, Montenegro and Albania. It is used as an herb with beneficial healing properties and its dried leaf (Salviae folium) is an authorized drug in most pharmacopoeias. Genetic diversity and structure of ten Dalmatian sage populations in Croatia has been analysed using AFLP markers. Five populations were collected in Istria and Kvarner (Šušnjevica, Kamenjak, Stara Baška, Cres, Lošinj) and five in Dalmatia (Hvar, Vis, Pelješac, Mljet, Konavle). Each population consisted of 25 plants. The four AFLP primer combinations yielded 1389 polymorphic fragments. Shannon's information index as a measure of genetic diversity within populations ranged from 0.327 (Vis) to 0.370 (Lošinj). The analysis of molecular variance was used to partition the total genetic variance into among and within populations. The most of the genetic diversity was attributable to differences among individuals within populations (93%) in concordance with the patterns expected for an outcrossing and moderately long-lived species. Allelic frequencies at AFLP marker loci in each population were calculated from the observed frequencies of fragments assuming Hardy-Weinberg equilibrium, using the Bayesian approach. A low level of genetic differentiation among populations (FST = 0.039) was observed. Neighbor-joining tree based on Nei's genetic distance matrix among populations revealed two clades supported by a high bootstrap value in accordance with geographical origin of the populations (Istra and Kvarner vs. Dalmatia). Regression analysis of geographic distances and pairwise FST values revealed a typical pattern of isolation-by-distance.