Selection of A clones from Thymbra spicata var. spicata by clonal selection method

The main objectives of our research were: (1) to evaluate clones among 28 locations of Thymbra spicata populations from the South-eastern Anatolia and Mediterranean region of Turkey, (2) comparing phytochemical content between populations under cultivated conditions, (3) to determine possible correlations between phytochemical content and morphological traits, along with (4) identifying yield-related traits for use in clonal selection programs. The investigated characters were plant height, plant canopy diameter, spike length, fresh herbage weight per plant, dry herbage weight per plant, dry leaf weight per plant, stem weight per plant, leaf/stem ratio and essential oil content per plant. Statistical analysis showed that populations had significant effect on most morphological parameters except stem weight per plant. Simple correlation analysis showed that dry leaf weight had significant and positive correlation with plant height, canopy diameter, fresh herbage and dry herbage (r = 0.623, 0.784, 0.954 and 0.983, respectively).Major compounds of essential oil of T. spicata are carvacrol, alpha-terpinene, 4-terpineole, 4-carene and alpha phellandrene. Carvacrol content of different populations ranged 62.2–78.8%. Due to high variability among wild populations these were considered important sources for breeding. The results further emphasize the possibility of selecting high yielding clones with high agronomic traits for development of a new variety or varieties, which will definitely reduce pressure on the nature for obtaining these plants.

► The study was carried out to develop clones/cultivars of T. spicata by selection from samples collected from 28 locations.
► The plant is very rich in terms of essential oil under culture conditions.
► Carvavrol content of different populations ranged 62.2% to 78.8%.
► The clones from Antakya-Harbiye, Sırnak-Center and Diyarbakir-Cermik populations were most superior in terms of dry leaf weight, whereas, the clones from Siirt-Center, Mersin-Tarsus, Antakya-Hassa and Sirnak-Center populations were most superior compared to others in respect of essential oil content.