Millefolii herba is one of the oldest and most important drugs in Lithuania, used both in folk and official medicine. The raw material is usually gathered from spontaneous populations. It would be reasonable to develop methods to identify the populations which produce high plant biomass and accumulate high levels of proazulenes. The quantitative variation of proazulenes and their relationships with phytosociological dependence and morphological characters of Achillea millefolium from wild populations has been examined. The vegetation records were made at 140 growing sites of A. millefolium. The species was found in 29 types of community representing different growing habitats. The resources of milfoils prevailed in dry grasslands of Arrhenatheretalia communities and ruderal habitats of Dauco-Meliliotion. The data on productivity and morphological characters were subjected to multivariate statistical analysis. A hierarchical cluster analysis indicated that higher productivity of A. millefolium populations was associated with their dependence on ruderal and segetal communities. The testing of A. millefolium plants revealed high variation for proazulenes in different communities. The proazulene-containing plants have been identified in 38% of all analysed cases. In the highest segetal and wasteland communities of Agropyretalia repentis, Sisybietalia, Digitario-Setarion, Aperion spicae-venti, Senecion fluviatilis only proazulene-free plants were found. Results of the ANOVA showed the proazulene-containing and proazulene-free plants significantly differed (P<0.05) for width of leaves and number of nodes. The presence of nodes in high number and narrow leaves in high proazulene-containing plants distinctly marked them from the proazulene-free plants. The study raised the possibility that selection based on the two morphological marker traits (node number and leaf width) and proazulene distribution in the populations would be effective for rapid identification of highly productive population(s) of pharmaceutical importance.
