Evaluation of Phenotypic Traits and Essential Oil Content in Wild-Grown Achillea biebersteinii Populations in Northeastern Türkiye

Achillea biebersteinii Afan., a medicinal and aromatic plant widely distributed in Türkiye, is valued for its essential oil content and bioactive compounds. This study aimed to investigate the phenotypic variation, yield performance, and essential oil content of A. biebersteinii populations collected from ten different locations in northeastern Türkiye. A total of six morphological and agronomic traits plant height (PH), inflorescence diameter (ID), stem diameter (SD), number of flowering branches (NFB), dry herbage yield (DHY), and dry flower yield (DFY) alongside essential oil content (EO), were evaluated. ANOVA results revealed statistically significant differences among locations for PH, DHY, and NFB, indicating strong environmental or genetic influences. In contrast, EO content showed no significant variation across locations, suggesting greater genetic stability. Correlation analysis indicated a strong positive association between NFB and DHY, while EO content was negatively correlated with PH and SD. Principal Component Analysis further clarified trait associations and revealed distinct groupings among locations, with L9 and L10 showing superior yield performance and L3 standing out for its high EO content. These findings highlight the substantial phenotypic and chemotypic diversity of A. biebersteinii in northeastern Türkiye and underscore the importance of location specific selection in breeding and conservation programs. The identification of high-yielding and high-quality populations provides a valuable resource for sustainable utilization of this species in medicinal and aromatic plant sectors.