Yarrow ( Achillea millefoilum L.) is an important medicinal plant with different medicinal and ornamental uses. In morphological studies, Fourteen morphological traits were assessed in which all traits showed significant differences (P 0.01) in six Achillea species. The compositions of essential oils of 19 accessions from six species were also analyzed. Total of 94 compounds were identified .The major constituents were determined as germacrene-D, bicyclogermacrene, camphor, borneol, 1,8-cineole, spathulenol and bornyl acetate and four chemotypes were defined based on major components. In this study, SSR markers were developed for the first time from the genome of A. millefolium using the slightly modified Hamilton protocol. A total of 30 primer pairs were developed of which 16 were polymorphic. Cluster analysis divided the studied genotypes to four major groups based on their geographical differentiation. Amplified Fragment Length Polymorphism (AFLP) markers were applied to assess the genetic diversity of 57 Achillea accessions belonging to five species. The dendrogram generated revealed five major groups that correspond to five species .The clustering based on AFLP markers was almost corresponded with that of geographical and evolutionary origins of the genotypes. Key Words Achillea , Morphology, Essential oil, SSR, AFLP Introduction Yarrow ( Achillea L.) is one of the youngest evolutionary genera of Asteraceae family which is spread all around the world. More than 100 species have been recognized in this genus [3]. Nowadays, different medicinal functions of yarrow such as spasmolytic, choleretic, treatment of wounds and anti-inflammatory activities, have made it known as an important medicinal plant [2,3]. Furthermore, some Achillea species are considered as ornamental crops. So, different morphological and essential oil variation could be observed in genotypes of various species of Achillea . Genetic diversity is of great importance to the sustainability of plant populations. In conservation management of a species, knowledge of intraspecies genetic variations might help to assess extinction risks such as inbreeding and evolutionary potential in a changing world [5]. Microsatellites are polymorphic among and within species, multi-allelic and co-dominantly inherited molecular markers, which have become the marker of choice in plant genetics and breeding studies. The SSR markers have not been yet characterized in this genus. Therefore, development of SSR markers will be efficient in assessment of genetic relationships of all Achillea species along with polymorphic AFLP markers.
