Karyotypic studies on some cultivated and wild species of Chenopodium (Chenopodiaceae)

Detailed karyotypic studies have been done in 20 wild and cultivated taxa of Chenopodium, which belong to three ploidy levels 2x, 4x and 6x. C. quinoa ( 4x) shows minor but consistent differences in the arm ratio of various chromosomes within the complements of different accessions. The chromosomes can be arranged in 18 pairs that suggest allotetraploid nature. The karyotype of C. berlandieri subsp. nuttalliae ( 4x) is basically similar to that of C. quinoa. C. bushianum ( 6x) is distinctly different from the above two species in showing highest ratio between longest and shortest chromosomes. C. album complex is characterized by consisting of 2x, 4x and 6x cytotypes. Marked karyotypic differentiation is seen even among various 2x accessions. The 4x cytotype has a more asymmetrical karyotype as compared with 2x and 6x cytotypes. The karyotypic differences are also apparent between two 6x cytotypes studied. C. strictum ( 6x) and C. giganteum ( 6x) show close similarity to 6x types of C. album.