Agronomic evaluation and essential oil composition characterization of Origanum compactum accessions cultivated in Morocco

Abstract

Origanum compactum is one of the most important aromatic and medicinal species, widely used in Morocco for various therapeutic and culinary purposes. The present study was carried out to evaluate the agronomic behavior of the species over two years of cultivation (2015-2016) and to characterize the chemical compositions of cultivated accessions under Moroccan pedoclimatic conditions. The 88 investigated O. compactum accessions, are originating from different bioclimate and geographical zones, representing all areas where the species is growing in Morocco. Agronomic performances varied significantly according to genotypes and cropping year. The accessions showed satisfactory adaptation capacity to cropping. Higher essential oil (EO) yields were observed in the second crop year, and plants belonging to carvacrol and thymol chemotypes were the richest in oil. A chemical variation of cultivated plants was detected for samples dominated by p-cymene and/or γ-terpinene, where the percentages of these components decreased in the second year of cultivation against a significant increase in carvacrol and thymol content. However, most of the EOs compositions of plants rich in carvacrol, thymol and carvacryl methyl oxide conserved their composition after cultivation. The different associations found between chemical and agronomic characters would help breeders to develop improved O. compactum cultivars with desirable agronomic and chemical traits. O. compactum has great cultivation ability and therefore, it could be a promising alternative to ensure a sustainable utilization of this threatened medicinal and aromatic species.