Comparative Chemical Composition of Essential Oils in Dill (Anethum graveolens L.) Ecotypes: Focus on Univariate and Factor Analysis

Anethum graveolens L. is a vegetable-aromatic medicinal herb of Apiaceae family and cultivated in different parts of the world including Iran. The aim of this study was to study the chemical composition of essential oils in four Iranian dill ecotypes. The extracted essential oils compositions were different in the ecotypes so that 38, 27, 25, and 24 volatile constituents were identified in Ardabil, Isfahan, Mashhad, and Kerman ecotypes, respectively. Eighteen compounds such as Toluene, α-thujene, camphene, sabinene, β-pinene, β-myrcene, α-phellandrene, α-terpinene, β-phellandrene, undecane, sabinol, dill ether, carvacrol, germacrene D, dill apiole, neophytadiene, hexahydrofarnesyl acetone, and phytol were recognized in all ecotypes but in different amounts. Analysis of variance showed the significancy of α-thujene, β-pinene, β-myrcene, α-phellandrene, β-phellandrene, undecane, dill ether, sabinol, germacrene D, dill apiole, neophytadiene, and hexahydrofarnesyl acetone at 0.001 probability levels. Means comparison of significant compounds showed highest mean values for β-pinene, undecane, germacrene D, neophytadiene, hexahydrofarnesyl acetone, and phytol in Ardabil ecotype; α-thujene, β-myrcene, β-phellandrene, and dill ether in Mashhad ecotype; and α-phellandrene, sabinol, and dill apiole in Kerman ecotype. Factor analysis indicated that three main and independent factors accounted for 100% of the total variance. The first, second, and third factors with 47.5, 31.9, and 20.63 % of variance included 9, 6, and 4 compounds, respectively. The knowledge of essential oil compositions of the studied ecotypes could be useful to choose the appropriate for breeding purposes based on phytochemical diversity or for use in pharmaceutical and food industries for extraction of special compounds.