Giemsa C-banded karyotypes of South American Hordeum (Poaceae): I. 14 diploid taxa

Abstract

The C-banded karyotypes of the 12 diploid, South American Hordeum taxa, H. stenostachys, H. chilense, H. flexuosum, H. euclaston, H. comosum, H. pubiflorum, H. patagonicum ssp. patagonicum, ssp. setifolium, ssp. santacrucense, ssp. mustersii, and ssp. magellanicum, and H. erectifolium, were similar, with four metacentric, one submetacentric, and two SAT-chromosome pairs, one metacentric pair with long and one submetacentric pair with shorter satellites. The banding patterns normally had between 4 and 12 very small or small bands per chromosome occurring at telomeres and centromeres, at the nucleolar constrictions, and intercalarily with no preferential disposition. Compared to the common karyotype, H. muticum and H. cordobense had corresponding banding patterns, but in H. muticum the metacentric SAT-chromosome pair was replaced by a metacentric pair without satellites, and in H. cordobense it carried small satellites, possibly produced through a paracentric inversion. The overall similarity of the C-banded karyotypes supports the view (i) that the South and North American diploids are closely related; (ii) that they contain the same basic genome (H); and (iii) that the biological relevance of referring the taxa to three sections is questionable. C-banded karyotypes are normally not a good diagnostic character in this material.