Comparison of the Giemsa C-banded and N-banded karyotypes of two Elymus species, E. dentatus and E. glaucescens (Poaceae; Triticeae)

The karyotypes of Elymus dentatus from Kashmir and E. glaucescens from Tierra del Fuego, both carrying genomes S and H, were investigated by C- and N-banding. Both taxa had 2n = 4x = 28. The karyotype of E. dentatus was symmetrical with large chromosomes. It had 18 metacentric, four submetacentric and six satellited chromosomes. The karyotype of E. glaucescens resembled that of E. dentatus, but a satellited chromosome pair was replaced by a morphologically similar, non-satellited pair. The C-banding patterns of both species had from one to five conspicuous and a few inconspicuous bands per chromosome. N-banding differentiated the chromosomes of the constituent genomes by producing bands in the H genome only. The S genomes of both species were similar with five metacentric and two satellited chromosomes having most conspicuous C-bands at telomeric and distal positions. They resembled the S genome of the genus Pseudoroegneria. The H genomes had four similar metacentric and two submetacentric chromosomes. The seventh H genome chromosome of E. dentatus was satellited, that of E. glaucescens nonsatellited, but otherwise morphologically similar. The C-bands were distributed at no preferential positions. The H genome of E. dentatus resembles the H genomes of some diploid Hordeum taxa.