Essential oil diversity in North American wild tarragon (Artemisia dracunculus L.) with comparisons to French and Kyrgyz tarragon

Although Artemisia dracunculus is a native species widely distributed across western North America, the essential oil composition of plants from this region has not been as extensively studied as its Asian populations. Essential oil extracted from 63 cultivated individuals of this species, originating from 18 different diploid North American wild populations, one cultivated octoploid individual from seed collected in Kyrgyzstan, and five cultivated tetraploid French tarragon plants, were analyzed by gas chromatography-mass spectroscopy. The diploid individuals exhibited a variety of volatile profiles with major components including (Z)-beta-ocimene (22 samples), methyl eugenol (15 individuals), methyl chavicol (10 individuals) and alpha-terpinolene (5 individuals). Many of the samples had high concentrations of the polylacetylenes capillene, 5-phenyl-1,3-pentadiyne and 1-(4-methoxyphenyl)-2,4-pentadiyne. The isocoumarin acetylene, capillarin, was also found in the majority of (53) samples but was generally found in low amounts (less than 4%). The volatile oil from tetraploid French tarragon samples contained approximately 80% methyl chavicol. The octoploid sample from Kyrgyzstan was found to have a unique profile with its main constituents being myrcene, (Z)-artemidin and limonene. Six major clusters were formed in the UPGMA cluster analysis and showed groups rich in (1) methyl chavicol, (2) methyl eugenol, (3) alpha-terpinolene, (4) capillene, (5) 5-phenyl-1,3-pentadiyne and (6) (E)-beta-ocimene/(Z)-beta-ocimene. These results show that North American wild tarragon is a potential source for unique oils and can serve as sources of genetic materials in plant breeding. (C) 2013 Elsevier B.V. All rights reserved.