Evaluation of Mentha arvensis, Mentha x piperita and Mentha spp. genotypes for menthol production

The genus Mentha has 18 species and many chemotypes with inter and intra specific differences. In spite of its great phytochemical diversity, the main economic interest on mint essential oil production is to obtain the constituent menthol. We evaluated the menthol production of 19 genotypes of three Mentha species. The experiment was carried out at field conditions in a randomized block design comparing the vegetative development, essential oil productivity and composition in two harvests. The plants were obtained by stem cuttings from adult plants maintained at greenhouse conditions. The plants were transferred to field at September and harvested in 90-day intervals. Some genotypes, even with high biomass production did not present menthol in the essential oil composition. The highest menthol production was obtained from the genotype 'Peppermint' (Mentha x piperita) with 34.37 mL/plant of menthol at the second harvest. The Mentha arvensis genotypes, traditionally grown because of its high menthol yield, presented low biomass production and essential oil and menthol productivity because of the high incidence and severity of "mint rust".