Karyotype Analysis and Systematic Relationship in the Iranian Astragalus L. (Fabaceae)

The karyotype characteristics of 24 taxa of Iranian Astragalus genus from different geographic origins were studied and their relation with a systematic classification of studied taxa was discussed. Chromosome numbers based on x = 8 were found in all of the taxa. Diploid (2 n = 2 x = 16) and tetraploid (2 n = 4 x = 36) chromosome number were recorded in 12 taxa representing nine species and in 12 taxa representing six species, respectively. The degree of karyotype asymmetric is set by values of A 1 , AR, CI, TF%, SA%, and LA%. Thus, the greatest value of A 1 , AR, and LA% and the greatest value of CI, TF%, and SA% were shown in A. stevianus (accession 20105) and A. cyclophyllon (accession 18375), respectively. The size of chromosomes in the studied taxa ranges between 1.930 μ in A. cyclophyllon (accession 18375) and 4.095 μ in A. bombycinus (accession 20114). By using Ward cluster analysis, the relation of studied taxa based on karyotype characteristic was shown. In this plot, all of the taxa were located in four groups on karyotype characteristics similarity. This grouping was then compared with their traditional systematic classification.