Characterization of Pimpinella anisum Germplasm: Diversity Available for Agronomic Performance and Essential Oil Content and Composition

Anise (Pimpinella anisum L.) is one of the most important annual herbs of the Apiaceae family, widely cultivated in southern Spain. Their seeds are highly valued for culinary uses and for producing quality essential oils widely used in food and beverage products, as well as for industry, medicinal, and cosmetics applications. This study investigates the seed yield and essential oil content within a set of 50 anise accessions from worldwide origin, as well as their composition by GC–MS and GC–FID analysis. Accessions showed significant differences in the agronomic parameters measured, including plant height (cm), seed yield (kg ha−1), and the Harvest Index (%), with accessions PA_87 (Spain), PA_47 (Greece), and PA_21 (unknown origin) being the most performant. Essential oil (EO) content varied between 0.8% and 5.7% across different genotypes, resulting in EO production values ranging from 0.1 to 300 kg ha−1. Trans-anethole was identified as the dominant terpene, comprising 84.4% to 94.4% of the content, followed by eugenol (1.4% to 5.5%) and α-muurolene (1.4% to 7.2%). PCA analysis identified five distinct groups and one outlier, influenced by minor terpenes. Indeed, there was a strong negative correlation between estragole and pseudoisoeugenyl 2-methylbutyrate. This study underscores the significance of minor terpenes, which play crucial roles in defining unique aniseed chemotypes, allowing for the selection of cultivars optimized for specific uses in food, cosmetics, and pharmaceuticals. Additionally, these findings emphasize the impact of cultivar genetics on agronomic traits and EO profiles, suggesting the need for further research to optimize plant growth and yield and EO quality.