Climate Variables of the Sites of Origin and Genotype Influence on Phenolic Compounds Accumulation in Cultivars of Myrtus communis L.

Myrtle (Myrtus communis L.) is an aromatic and medicinal plant spreading in the Mediterranean area. The main uses of myrtle plants are liqueur and essential oil production with several biological properties. A large part of the properties of these products is due to phenolic compounds. Twenty-two myrtle cultivars originating from several areas of Sardinia Island and cultivated at the same site were analysed for phenolic compounds determination. Pearson's correlation was used to investigate a possible correlation between phenolic compounds content observed in the cultivation site and historical agrometeorological parameters in the sites of cultivar origin. Hierarchical cluster analysis (HCA) and principal component analysis (PCA) were applied to data to evaluate the characterization of myrtle cultivars based on the relationship between sites of origin with their climate traits and phenolic compounds content as recorded in the same field of comparison. Anthocyanins are negatively correlated with minimum, maximum, and average temperatures of some months. Total phenols content decreases with high temperatures in the summer months. Rainfall affected mainly tannins content. Two principal components explained about 79% of the variability and allowed the classification of cultivars into four groups, while cultivars from Laconi, Siniscola and Cuglieri sites were not included in any group. The HCA allowed the subdivision of the wild populations into three clusters.