Velvet: An alternative high-yielding peppermint clone for oil production

Peppermint oil is one of the most widely recognized natural flavors. It is mainly produced commercially by extraction from two main types of cultivars: Black Mitcham (Mentha × piperita L.), a sterile polyploid and the backbone of peppermint oil production in the United States, and Arvensis (Mentha arvensis L.), the main cultivar used for peppermint oil extraction in India. Here, we present the identification of an accession called Velvet that is publicly available at the US National Plant Germplasm System and exhibits potential as an alternative peppermint-type oil producer. Despite its original classification as a diploid, we found that Velvet exhibits a nuclear DNA content close to that of Black Mitcham and higher than those of diploid and tetraploid mint accessions, suggesting a high ploidy level. A trial for cut date optimization suggested that one cut, between 117 and 124 days after sowing, is the optimal strategy for oil production. Analytic profiles of the oil produced by Velvet across years confirmed that Velvet produces a peppermint-type oil with high menthol content (67%), and an overall oil profile similar but distinguishable from that produced by Mentha arvensis clones. Multi-year field trials showed that Velvet exhibits great potential for mint oil production, with up to 38% yield increase compared to the control, Black Mitcham. The identification of an additional peppermint-type oil producer presents new opportunities for farmers and the mint industry in their search for new superior clones, but also new germplasm to help decipher the genetic basis underlying peppermint oil production.