Yield and quality of ‘Greek oregano’ (Origanum vulgare L. subsp. hirtum) herb from organic production system in temperate climate

Abstract

Oregano (Origanum vulgare L.) is an important medicinal and aromatic plant. The purpose of this study was to determine the possibility of organic cultivation of ‘Greek oregano’ (Origanum vulgare L. subsp. hirtum) within temperate climate conditions in Poland. Two variants of field experiments were applied: open field and foil tunnel. Results showed that plants cultivated under foil tunnel were characterized by almost twice the mass of the herb when compared to those from open field (76.49 and 49.44 g of dry mass per plant, respectively). The herb was analyzed for total content of essential oil, phenolic acids, flavonoids, chlorophyll a and b. The composition of essential oil was determined by GC–MS (gas chromatography - mass spectrometry). Raw material harvested from plants cultivated in foil tunnel was distinguished by higher content of flavonoids, chlorophyll a and b as well as essential oils in comparison to those from open field. However, the content of phenolic acids was higher in herb collected from plants grown in open field. There was no clear relationship between the cultivation method and essential oil composition, where carvacrol was a dominant (up to 73.85%). Observed differences concerning both yield and content of biologically active compounds seems to be associated with various climatic parameters (especially temperature) recorded in both variants of cultivation. The results of sensory evaluation (Quantitative Descriptive Analysis) showed that the herb from foil tunnel was characterized by a slightly higher intensity of coniferous and less spicy odor notes, as well as more astringent taste, in comparison to the one from open field. In general, the results indicate that ‘Greek oregano’ can be successfully cultivated in Polish climate, in organic system.