Chromosome counts report of six Astragalus L. (Fabaceae) species from Iran

Somatic chromosome numbers of six endemic and rare species of the genus Astragalus were studied. The basic chromosome number for all studied species was x = 8. Five of the studied species including A. assadabadensis, A. carduchorum, A. kirrindicus, A. nervistipulus, and A. microcephalus subsp. pycnocladus were diploid and A. trachyacanthos was tetraploid. The chromosomal parameters of the species were calculated and their idiograms were drawn. The karyotypic formula of the species was different, but in all species most of the chromosomes were metacentric and there were zero to three submetacentric chromosomes. Astragalus assadabadensis had the longest chromosomes and A. trachyacanthos had the shortest chromosomes. Chromosome count of three species including A. carduchorum from the sect. Acidodes, A. microcephalus subsp. pycnocladus and A. trachyacanthos from the sect. Rhacophorus are reported for the first time.