Chemical variability in the essential oil components of Achillea millefolium agg. from different Himalayan habitats (India).

Essential oil diversity was studied in wild Achillea millefolium from two different high altitude Himalayan habitats (1600 m, 2850 m) and their cultivated populations under uniform environmental conditions at lower altitudes of Jammu (300 m). The populations proved to represent two different ecotypes: the 1,8-cineole type and the borneol type with appreciable differences in the contents of oils and mono- and sesquiterpenes. Populations from all these habitats showed considerable overlap in various constituents and the major components were characterized as beta-pinene (10.6 % - 17.7 %), 1,8-cineole (3.0 % - 15.1 %), borneol (0.2 % - 12.1 %), and beta-caryophyllene (8.5 % - 16.2 %). No variation in morphology and chromosome number was observed under comparable environmental conditions from different habitats. Preliminary investigation indicates the existence of different ecotypes from the Himalayan habitats.