**5. Conclusions**

The present study emphasized that RAPD analysis allowed a perfect distinction between the Korean thyme cultivars (Wolchul and Odae) and commercial thyme cultivars, based on their unique genetic background. However, the chemical composition of the Wolchul and Odae cultivars was not identical. Furthermore, there was no significant relationship between the RAPD data and essential oil composition of both *T. quinquecostatus* and *T. vulgaris* cultivars. The chemical composition and molecular data obtained in this study delivered a good starting point for future investigations. It could be concluded that the RAPD markers proved to be an e ffective tool for discriminating di fferent *Thymus* species. The sample collection must be done from di fferent geographical regions in Korea to understand the genetic and chemical variability of the *T. quinquecostatus* cultivars.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2079-6382/9/6/289/s1, Figure S1: GC-MS chromatograms of essential oils from three Korean native *Thymus quinquecostatus* cultivars. A, Odae cultivar; B, Wolchul cultivar; C, Jiri cultivar.

**Author Contributions:** M.K. performed the experiment; K.S. compiled the data and wrote the manuscript; J.-C.M. analyzed the data; and S.K. designed the experiment and revised the manuscript. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** This study was carried out with the support of "Cooperative Research Program for Agriculture Science and Technology Development (Project No. PJ014506012020)", Rural Development Administration, Republic of Korea.

**Conflicts of Interest:** The authors declare no conflict of interest.
