Economic valuable traits of promising breeding samples and ‘Chornolysta’ variety of Mentha piperita L. after in vitro sanitation and micropropagation

Purpose. To study the impact of clonal micropropagation and sanitation in vitro by viricide Ribavirin on ex vitro plant productivity, quantitative content and qualitative composition of peppermint essential oil components obtained from four breeding samples of peppermint plants (Mentha piperita L.) and the ‘Chornolysta’ variety. Methods. The study used methods of field agrotechnical one-factor experiment, essential oil distillation with water vapor according to the Ginzberg method, capillary gas chromatography and statistical analysis. Results. Due to the sanitation process in vitro, the yield of air-dried leaves of breeding samples increased by 2.9–7.1%, the ‘Chornolysta’ variety by 51.4% and rhizomes by 2.2–3.8% and 28.5% respectively, which amounted 0.35–2.74 t/ha. A significant increase of essential oil yield of breeding samples from 4.0 to 9.9 kg/ha was shown, and of the ‘Chornolysta’ variety – up to 28.6 kg/ha. After in vitro sanitation and clonal cropropagation of the breeding sample M 01-12, the content of essential oil was more than 4%. The following components of peppermint essential oil were identified: limonene, cineole, menton, mentofuran, isomenton, menthyl acetate, β-caryophyllene, isomenthol, menthol, pulegon, piperitone and carvone. A clear tendency to a decrease in the amount of menton and isomenthol with isomenton and menthol increase in plants, sanitated and propagated in vitro, was revealed. Conclusions. The use of tissue and organ culture methods and in vitro sanitation improves the qualitative composition of terpenoids by increasing the amount of menthol and menton reducing. The data obtained on the composition of terpenoids should be considered in peppermint selection as one of the integral criteria, which should be included in the list of economically valuable characteristics of peppermint plants, such as foliage, biomass of air-dried leaves, plant rhizomes and the amount of peppermint essential oil. Six indicators of the essential oil of the breeding sample M 01-02, namely citric acid, cineole, mentofuran, isomentone, pulegon, carvone, as well as the cineole / limonene ratio, meet the criteria of the European Pharmacopoeia, so it can be considered as promising for cultivation among the studied samples.