Effect of clonal reproduction on quantitative indices and component composition of essential oil of peppermint varieties

Quantitative and qualitative composition of essential oils of peppermint breeds Lebedinaya Pesnya, Lubenchanka, Lidiya, Ukrainskaya Perechnaya, Mama, Chornolista was investigated before and after clonal microreproduction by the method of isolated tissues and bodies culture in vitro. Methods of essential oil steam distillation, capillary gas chromatography and statistical analysis were used in the research. It is established that increase in essential oil quantity was observed for peppermint breeds on which reproduction and improvement іn vіtro technology was applied. As a result of clonal microreproduction of peppermint plants in culture іn vіtro on nutrient medium Murasige and Skug, in which the growth regulators 0.75 mg/l of 6-benzylaminopurine, 0.1 mg/l of adenine, 0.05 mg/l of indolil-3-acetic acid and 0.5 mg/l of gibberellins acid were added and virocide Ribavirin in concentration 10 mg/l, improvement was obtained in comparison with vegetatively reproduced plants; increase in essential oil quantity per hectare was established for the following breeds; Chornolista by 54.2%, Lebedinaya pesnya by 38.2%, Ukrainskaya Perechnaya by 36.7%, Mama by 28.5%, Lubenchanka by 17.1% and Lidiya by 11.6%. For oil content the highest indices were noted for Lubenchanka, Mama and Lebedinaya Pesnya peppermint breeds with product yield 4.02%, 3.98% and 3.84% respectively. It was established that the essential oil component composition in non-clonal peppermint plants raw materials and plants-regenerants after culture in vitro is variable depending on breed. Limonene, cineole, menthone, menthofuran, iso-menthone, menthyl acetate, β-caryophyllene, iso-menthol, menthol, pulegone, germacren, piperitone, carvone were identified in peppermint essential oil. High content of menthol, low content of carvone, piperitone, pulegone (except for Chornolista, Ukrainskaya Perechnaya breeds) and menthofuran (except for Chornolista, Ukrainskaya Perechnaya and Lubenchanka breeds) are characteristic for Ukrainian selection peppermint investigated breeds. A clear tendency to menthol and menthone content ratio increase is observed in plants which were improved in conditions іn vіtro. Pulegone was not detected in essential oil samples of Lebedinaya Pesnya, Lidiya and Mama breeds. Biochemical markers of Lebedinaya Pesnya, Lubenchanka, Mama breeds, which differentiate them within the group of investigated breeds, are higher limonene, piperitone and menthol pool; for Ukrainskaya Perechnaya and Chornolista breeds – pulegone, cineole and menthone; for Lidiya breed – iso-menthone.