Study of oregano (Origanum vulgare L.) cultivation in the Elvas region

Abstract

Origanum vulgare L. species is used as an herb, spice and medicinal plant, occurring spontaneously in the Alentejo region. Its sustainable cultivation should be promoted in order to reduce genetic erosion caused by harvest in nature.

The main goal of this study was to respond to the request of a farmer from the Elvas region, focusing on the assessment of the adaptation to cultivation of six accessions, three spontaneous (OV1 from Vila Fernando, OV2 from Estremoz, OV3 from Vila Boim) and the remaining three commercial (OVT1, OVT2, OVT3).

Plant propagation was carried out from stem cuttings for the three spontaneous accessions and from seed for the three commercial accessions. Using material from OV2, a stem cutting vegetative propagation trial was carried out, using softwood (terminal and sub-terminal) and semi-hardwood (basal) stem cuttings; cuttings survival and growth was observed. Seed germination was tested using the three commercial seed accessions and the three spontaneous accessions (harvest in nature and after cultivation) at 20°C with 12 h photoperiod. The following descriptors were observed on the filed characterization essay: flowering date; length, width and color of the basal leaf; growth habit; width and height of the plant; length of the main stem, length and width of the terminal inflorescence, flowered portion of the stem length and width; plant biomass (fresh and dry).

The subterminal stem cuttings survived better (83.8%) and survival rate was significantly higher than basal cuttings (56.8%). Seed germination varied from 69.5% to 92%, with significant differences between the commercial seeds and seeds of the spontaneous accessions after cultivation. On the characterization field essay, the flowering date was the only descriptor with significant differences between spontaneous accessions. The earliest-flowering accession was OV1 and the later-flowering accession was OV2. The difference between the flowering dates of these accessions was 13 days. The work provided useful information to the farmer for oregano growing, however the study should be continued.