Phytomorphological and Essential-Oil Characterization in situ and ex situ of Wild Biotypes of Oregano Collected in the Campania Region (Southern Italy)

Oregano is an aromatic species of great interest which spreads spontaneously in the Mediterranean area but its genetic resources are not yet adequately developed. Moreover the results of studies of wild strains of different origin - although quite numerous - are not always comparable, and therefore the effects of environment and genotype cannot be distinguished. The identify of three wild, white-flowered biotypes of oregano collected in the Campania Region (Southern Italy) and the assessment of the effects of genotype and environment through the comparison in situ and ex situ were studied. The determination allowed to identify the biotypes belonging to two different subspecies: Origanum vulgare ssp. virens and Origanum vulgare ssp. viridulum. The percentage of oil yield was higher for the biotype belonging to ssp. virens and it was significantly correlated with the glandular and stomatal density. The chemical characterization of the oils obtained by hydrodistillation was found to be influenced by the genotype and conditions of plant growth.