Salvia desoleana is a herbaceous perennial shrub endemic of Sardinia (Italy). The leaves are a source of essential oil, used in pharmaceutical and cosmetic industries. The therapeutic function of this species has been associated to the presence of essential oils rich in α/β-pinene, p-cimene, linalool, linalyl acetate and 1,8-cineole. Today the industrial request of Salvia essential oils is increasing and most of the biomass is exploited from the natural populations which are under severe risk of genetic erosion. In order to improve the essential oil production, the study of the environmental parameters that influence composition, quality and quantity of the essential oils, turns out to be necessary. Soil physical and chemical structure represents one of the determinant factors in secondary metabolites production, and could also be involved in volatiles fraction composition in the same species. The main aim of this research was to explore the relationship between essential oil profiles and soil characteristics in S. desoleana populations. GC/MS analysis performed on the essential oil extracts identified 22 principal compounds, which were extremely variable among the five S. desoleana populations studied. The analysis of the essential oils revealed different compositions in the terpenes fractions: 68.2% of monoterpenes, 27.3% of sesquiterpenes and 4.5% of diterpenes. Analysis of chemical and physical soil parameters at the collection sites revealed that silt and sand contents were correlated with α-pinene and sclareol fractions and the total K 2 O was significantly correlated to several compounds belonging to the three terpene fractions identified. These results will provide guidelines for the in site conservation and for the improvement of the commercial value of the species.

Salvia desoleana Atzei et Picci is a herbaceous perennial plant endemic to Sardinia, Italy. Its leaves are a source of essential oil, used in the pharmaceutical and cosmetic industries. Due to the increasing interest in the essential oils production, cultivated accessions have supplanted many wild populations which had become small, fragmented and isolated with a serious risk of genetic erosion. With the aim of preserving the local genetic diversity, AFLP fingerprinting has been used to facilitate the comprehensive evaluation of both cultivated and wild S. desoleana populations. A set of 165 polymorphic AFLP fragments was generated, revealing a genetic diversity (He) ranging from 0.11 to 0.22 in wild and cultivated populations respectively. Two major clusters were revealed by STRUCTURE analysis, one including wild and the other capturing the cultivated accessions. The divergence between the cultivated and wild materials was also confirmed by the analysis of molecular variance (F ST = 0.52). GC/MS analysis performed on the essential oil extracts identified 37 compounds, eight of which (1,8 cineole, terpinolene, a and b thujone, camphor, terpinyl acetate, germacrene D and linalyl acetate) were strongly represented. Three main fractions were identified in the essential oils: monoterpenes, sesquiterpenes and diterpenes. All terpenes levels were significantly correlated with the AFLP genetic clusters (P \ 0.0001), suggesting close correspondence between genetic groups and chemical profiles. This work aims to describe the integrated investigation of genetic and chemical diversity of S. desolena germoplasm, in order to improve the species yield and to plan a future conservation strategy.