Karyotypic study of six ecotypes of two species of yarrow; Achillea millefolium and Achillea santolina

In this research a cytological study was performed on six ecotypes of two Achillea species growing in Iran including Achillea millefolium and Achillea santolina. The root apical meristem of ecotypes was used. After pretreatment, fixation, hydrolysis, staining and selecting the appropriate metaphase plate and photographing of samples with photomicroscope was determined the chromosome morphology. The results showed that the basic number of chromosome is x=9 in 6 Achillea ecotypes. Three ecotypes including Aligoodarz, Meshkinshahr and Ardabil were diploid with 2n=2x=18 and three ecotypes including Arak, Ilam and Estahban were tetraploid with 2n=4x=36. The different Karyotypic parameters including L (chromosome long- arm length), S (chromosome short-arm length) and T (chromosome total length) were measured. The results showed that the maximum range of S was 1.2 in Aligoodarz ecotype and minimum range of S was 0.2 in Ardabil ecotype. The maximum range of L was 2.7 in Aligoodarz ecotype and minimum range of L was 0.8 in Ilam and Arak ecotypes. The maximum range of T was 3.9 in Aligoodarz ecotype and minimum range of T was 1.2 in Arak ecotype. The maximum range of Huziwara index %F was 20.84 in Meshkinshahr ecotype and minimum range of %F was 7 in Estahban ecotype. The maximum range of %RL was 7.82 in Aligoodarz ecotype and minimum range of %RL was 1.57 in Ilam ecotype. The evaluation of karyotypic symmetry parameters on Stebbins and Levan methods including %S, DRL, %TF showed that the most symmetric ecotype was Arak and the most asymmetric ecotypes were Estahban and Aligoodarz. Therefore Arak ecotype is old ancient species and Estahban and Aligoodarz ecotypes are new and more development.