Selection of fecund and chemically valuable clones of thyme (Thymus) species growing wild in Lithuania

The high infraspecific chemical and morphological polymorphism is characteristic for species of genus thyme (Thymus L.). This characteristic can be subservient to the selection of valuable clones from natural habitats. The objective of the present study was to select valuable Thyme clones from native flora of Lithuania according to the productivity of biomass and chemical composition of essential oils for the cultivation. Two Thymus species, namely large thyme (T. pulegioides L.) and wild thyme (T. serpyllum L.), grow wild in Lithuania and other Baltic States (Latvia and Estonia). Was established that T. pulegioides is more suitable for the cultivation than T. serpyllum, because can grow more dried total biomass (up to 3 times), are higher (2.8 times) and synthesize higher amount of essential oils with significant amounts of such biologically active compounds as the thymol, carvacrol, geraniol or linalool. Four most fecund clones of T. pulegioides (the total biomass of dried plant 29–45 g, the amount of essential oil in whole plant 0.5–0.7%) were selected which accumulate the highest amounts of thymol (up to 26.1%), carvacrol (up to 31.0%), geraniol (up to 45.0%) and linalool (up to 80.3%). The cultivation of these clones enables to get the high yield of biomass and chemically homogeneous herbal raw material of desirable chemical composition for the phytomedicines and phytocosmetics.