Variability of selected characters of production biology and essential oil accumulation in populations of Achillea crithmifolia

Although data on chemical properties of Achillea species are numerous, morphological studies are rare. Therefore, during 1995-97, some morphological and production biological characters (height, width, number of stems, dry flower mass and leaf colour) of Achillea crithmifolia, their stability over years and generations, their dependence upon plant age and their correlations with the accumulation of essential oil were examined. The populations investigated were raised from seed materials stored in the genebank of the Department. The considerable diversity of the populations indicated a high degree of heterozygosity of these traits in natural stands. Variability was highest in number of stems (15.3-37.4 pieces) and essential oil content (0.63-1.27%). This variability did not disappear during three successive generations of inbreeding, although a decrease in variance was observed. Essential oil content was shown to have a higher heritability than other properties. Correlations of plant height, width and number of shoots were medium (r = 0.539-0.757), and their correlation with the essential oil content was also significant. Both the year of examination and age of the plants exerted a strong influence on most of the characters studied.