Genetic, Phenotypic, and Commercial Characterization of an Almond Collection from Sardinia.

BACKGROUND: Recent nutritional and medical studies have associated the regular consumption of almonds with a wide range of health benefits. As a consequence, kernel quality has become an important goal for breeding, considering not only the chemical composition conferring a specific organoleptic quality but also physical traits related to industrial processing. METHODS: We characterized an almond collection from Sardinia through analysis of 13 morpho-physiological traits and eight essential oil profiles. The genetic structure of the collection was studied by analyzing the polymorphism of 11 simple sequence repeats (SSR). RESULTS: Both commercial and phenotypic traits showed wide ranges of variation. Most genotypes were early flowering with low yield potential. Several genotypes showed moderate to high yield and very interesting oil compositions of kernels. Based on 11 SSR profiles and Bayesian clustering, the Sardinian cultivars were assigned to groups which were differentiated for several agronomic and commercial traits. CONCLUSIONS: Several cultivars showed a high kernel oil content and high oleic to linoleic content ratio. Based on morphological traits, we propose that some of the analyzed cultivars could be interesting for industrial applications. Finally, we highlight the importance of characterizing early blooming cultivars for sites which are experiencing a rise in mean temperatures due to the effects of global climate changes.

Relationship Between Soil and Essential Oil Profiles in Salvia desoleana Populations: Preliminary Results.

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/ß-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 K20 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.

Genetic diversity in two Italian almond collections

Background Sweet-seeded domesticated almonds were brought to the Mediterranean Basin from central Asia about 4000 years ago. In Italy, most of the almonds produced are cultivated in the southern part of the country. Local populations of the tree in Sardinia are largely seed-derived and mostly self-incompatible, so have developed extensive genetic diversity. The need to protect biodiversity has prompted a revived interest in local genetic materials in almond. Two Italian collections have been established, one in Sardinia and the other in Apulia. These collections were the focus of the present evaluation of genetic diversity. Results Eleven SSRs (microsatellites) were used for fingerprinting. The Sardinian germplasm was highly polymorphic, revealing a mean of 14.5 alleles per locus and a mean heterozygosity of 0.71. Using a model-based clustering approach, two genetic clusters were distinguished: one included all the commercial varieties and most of the Sardinian accessions, and the other most of the Apulian accessions. A similar structure was produced using a distance-based cluster analysis. The Sardinian accessions could still be distinguished from the commercial germplasm with few exceptions. Conclusion The extensive genetic variability present in the Sardinian and Apulian almond germplasm indicates that these materials represent an important source of genes for the improvement of the crop.