Relationships in the barley genus (Hordeum): An electrophoretic examination of proteins

The relationships between all known Hordeum species except H. guatemalense were inferred from the electrophoresis of the six enzyme systems Got, 6-Pgd, Mdh, Idh, .alpha.- and.beta.- amylases. A total of eleven loci were scored for in these systems. Maximum likelihood clusters and Wagner networks calculated from the electrophoretic data divided the genus into three groups, viz. the "H. vulgare group", the "H. marinum group" and the "H. pubiflorum group".

Only one of these groups was recognized in the morphological sectioning of the genus. Most of the polyploid cytotypes in the genus seemed to have originated as alloploids. Phylogenetic links between diploid and polyploid taxa are suggested from the enzyme phenotypes. An evolutionary theory for the genus Hordeum is proposed, with two centres of differentiation, in South-West Asia and South America, respectively.