Genotype-environment-year interaction on oil antioxidants in an olive district of Northern Italy

A two-year survey in 18 representative groves of a north Italian olive district sampled cvs. 'Caltivar' and 'Leccino' for single-site oils. Polyphenols had a major role in determining oil autoxidation stability with respect to tocopherols, even if the higher autoxidation stability of 'Leccino' over 'Casaliva' was probably due to the more than double content in tocopherols, which was significantly affected by years. In spite of the large variations both in oil and in environmental parameters, no statistically significant model emerged for relations between antioxidants oil content and site parameters.