Morphological, yielding and quality descriptors of four clones of Origanum spp. (Lamiaceae) from the Argentine Littoral region Germplasm bank

Abstract

In order to preserve, characterize and improve the quality of some accessions in Entre Ríos province, Argentina, a germplasm bank of aromatic and medicinal plants has been set up, including among other species, the oregano (Origanum spp.). To simplify the identification and characterization of the accession entries belonging to this genus, a chart containing 41 descriptors has been elaborated to allow the easy and quick individualization of any material being added to the collection. The first four accessions added to the collection were characterized using this chart and studied taking into account their biomass and essential oil yields and the quality of their volatile fraction. The materials analyzed are locally known as ?27-09?, ?Peruvian? and ?native? clones and are taxonomically identified as hybrids of Origanum × majoricum Cambess; and a fourth material, known as ?green Spanish? clone belonging to the species Origanum vulgare L. ssp. viridulum (Martrin-Donos) Nyman. The essential oil yield was similar for all the materials (1.7% (v/w) on dried basis). The estimated aired biomass yield was superior for the Origanum × majoricum hybrid clones (ranging from 4700 to 11,900 kg ha−1), whereas the ?green Spanish? clone only reached a biomass of 2450 kg ha−1. Meanwhile, based on the quality of the essential oils, O. vulgare ssp. viridulum was more promissory, since it corresponded to a carvacrol type oregano. Finally, it will be necessary to assess the role of the agronomical and ecological variables on the latter clone, in order to increase the content of carvacrol in the essential oil and, at the same time, to improve its biomass yield.