Fennel (Foeniculum vulgare Mill.) is an important medicinal plant and has several subspecies and varieties. In this study, 20 fennel genotypes belonging to four important subspecies and/or varieties from 17 countries were evaluated for essential oil components, seed yield, and essential oil content during 2 yr (2015–2016). High genotypic variation was observed among and within subspecies and/or varieties for all the measured traits. Based on the gas chromatography–mass spectrometry analysis, transanethole (22.37–86.47%), estragole (2.47–25.86%), fenchone (4.96–19.79%), and limonene (0.53–11.87%) were detected as major essential oil components. Comparing the subspecies and/or varieties showed that the ssp. piperitum had the highest average of limonene and estragole, and the lowest average of transanethole and seed yield. Based on the principal component analysis, var. vulgare, var. dulce, and var. azoricum were categorized in one group, and ssp. piperitum was separately grouped, confirming two major separate subspecies. The highest essential oil content was observed in the second year in all the subspecies and varieties. However, the studied subspecies and/or varieties had different values of phytochemical traits across the years. The negative correlation between some essential oil components indicates that some components are isomers and it can limit the simultaneous selection of components. The high variation in the studied germplasm may be utilized to select useful samples for medicinal, industrial, and other purposes.

中文翻译：

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茴香基因型中植物化学成分的遗传变异性

茴香（Foeniculum vulgare Mill.）是一种重要的药用植物，有多个亚种和品种。在这项研究中，对来自 17 个国家的 4 个重要亚种和/或品种的 20 个茴香基因型进行了 2 年（2015-2016 年）的精油成分、种子产量和精油含量评估。对于所有测量的性状，在亚种和/或品种之间和内部都观察到了高基因型变异。基于气相色谱-质谱分析，检测到转茴香脑（22.37-86.47%）、草蒿脑（2.47-25.86%）、茴香酮（4.96-19.79%）和柠檬烯（0.53-11.87%）是主要的精油成分。比较亚种和/或品种表明 ssp。胡椒柠檬烯和草蒿脑的平均值最高，而转茴香脑和种子产量的平均值最低。基于主成分分析，var。粗俗的，变种 dulce和 var。azoricum被归类为一组，而 ssp。胡椒被单独分组，确认了两个主要的独立亚种。在所有亚种和品种中，第二年观察到最高的精油含量。然而，研究的亚种和/或品种多年来具有不同的植物化学特征值。一些精油成分之间的负相关表明一些成分是异构体，它可以限制成分的同时选择。所研究种质的高度变异可用于选择用于医药、工业和其他目的的有用样品。