Karyotype analysis and chromosome number for two Cirsium taxa (Asteraceae) in Iran

Abstract

Cirsium Mill. contains more than 250 species in the world mainly distributed in the Northern hemisphere. Different chromosome numbers with different ploidy levels were reported in this genus. In this study, karyotype details and chromosome numbers were established for two Cirsium taxa in Iran. C. ciliatum subsp. szovitsii and C. echinus had the mitotic chromosome numbers of 2n = 2x = 34. Karyotype analyses showed that chromosomes were generally metacentric and sub-metacentric. In C. echinus, Lowshan population had the longest chromosome (19.10 µm) and Heyran Canyon population (4.73 µm) the shortest one while in C. ciliatum, the longest chromosome was observed in Urmia to Salmas population (14.67 µm) and the shortest one (4.71 µm) in Doshanlu population. Total haploid chromosome length ranged from 275.29 to 376.42 µm in populations studied. Both taxa were grouped in 2B class. B-chromosomes were recorded for two taxa studied too. Chromosome type, mitotic chromosome numbers and occurrence of B-chromosomes were in agreement with previous results (Albers, Pröbsting, 1998; Lövkvist, Hultgård, 1999; Yüksel et al., 2013; Yildiz et al., 2016).