Characterization of Sicilian olive genotypes by multivariate analysis of leaf and fruit chemical and morphological properties

Abstract

Leaf and fruit size and shape were measured and mannitol, glucose, sucrose and malic acid were quantified in leaf, bark and fruit of 25 Sicilian olive genotypes. Multivariate analysis was used to individuate groups with similar chemical composition and morphological traits suggesting potential for stress tolerance and/or oil yield and quality. Mannitol content varied greatly among genotypes and was the most abundant carbohydrate in leaf and bark, whereas glucose was the most abundant in fruit. Sucrose and malic acid were generally low indicating a marginal role in olive tissues. Mannitol and glucose were directly related in both leaf and fruit tissues. Genotypes also differed for carbohydrate partitioning among tissues, and multivariate analysis individuated a group of seven genotypes associated to leaf length:width, length:area, glucose, mannitol, and sucrose, which should stand for environmental stress tolerance. Multivariate analysis also individuated a group of six genotypes associated to malic acid, oleic acid, oleic:linoleic, and polyphenols, and therefore showing potential for production of high quality and stable olive oil. Overall, three of the 25 genotypes in trial seem to combine a good degree of abiotic stress tolerance with production of high quality and stable olive oil.