Karyological data of five autumn-flowering Crocus L. species from Iran

Corms and herbarium vouchers of 23 accessions belonging to five autumn-flowering Crocus species were gathered from nine Iranian provinces. For the materials under investigation, chromosome numbers, karyotype formulas and idiograms were documented. Chromosome number of 2n = 12 is reported for the first time in C. archibaldiorum and in the studied accessions of C. speciosus aggregate. Also, 2n = 24 were found in C. caspius, 2n = 8 and 10 in C. damascenus, and 2n = 14 and 16 in C. haussknechtii. In the latter two species, variation in chromosome number was correlated with karyotypic differences. Notably, C. archibaldiorum (2n = 12) had a longer total haploid of chromosome length than C. caspius (2n = 24). On a distribution map, possible correlations between karyological data and geography were indicated. To quantify variation in karyotypes, three inter- and intra-asymmetric karyotypic parameters were estimated. Also, statistical analyses were performed on five karyotypic characters to infer karyological relationships. The members of section Crocus (only C. haussknechtii) and section Nudiscapus occupied distinct positions. Furthermore, at the species level, all accessions of the same species tended to group together. The remarkable karyotypic variation among the studied accessions of C. damascenus and C. haussknechtii supported the previous assumption that these taxa still include undescribed species. It is underlined that changes in chromosome number and structure have played an important role in the evolution of the genus Crocus.