Variation in Terpene and Linear-Chain Hydrocarbon Content in Yarrow (Achillea millefoliumL.) Germplasm from the Rhaetian Alps, Italy

Yarrow (Achillea millefolium L.) is a herbaceous species common in the Alpine region of Europe
and used in folk medicine since antiquity. Its organs are rich in monoterpenes and sesquiterpenes, two
subclasses of plant terpenoids with relevant ecological significance, which were reported as valuable
markers for the traceability of mountain dairy products. The variability in chemical composition of
yarrow germplasm may be related with its genetic diversity, accounting for possible differences in
medical properties, and supporting its use as a specific territorial marker. Aim of this work was to assess
the leaf chemical composition of 16 yarrow populations collected at altitudes exceeding 1600 m in three
valleys of the Rhaetian Alps, Italy, and jointly evaluated in a lowland site. The most abundant compounds
detected generally differed from those of the germplasm from other countries. A trend of valley-specific
pattern of composition was evident. However, the variability among individual populations was even
more remarkable, regardless of their valley of origin. The concentrations of sesquiterpene hydrocarbons,
oxygenated monoterpenes, and oxygenated sesquiterpenes discriminated the populations in multivariate
analysis. A few prevailing chemotypes were characterized, which differed from those previously reported
in the literature. The geographic isolation from other germplasms, and the local ecotypization, likely
originated a chemically distinct gene pool.