Isoenzyme variation in barley (Hordeum L.) 2. Aspartate aminotransferase and 6-phosphoglyconate dehydrogenase

Abstract

Isoenzymes of aspartate aminotransferase (AAT) and 6-phosphoglyconate dehydrogenase (PGD) have been studied by polyacrylamide gel electrophoresis (PAGE) to elucidate phylogenetic relationships among Eurasian barley species. H. vulgare, H. spontaneum and H. bulbosum share the same electrophoretic phenotype of AAT different from those of the Murina group. This supports the inclusion of H. bulbosum in the type section, but argues against the inclusion of the Murina group. H. murinum s. str. (4x) and H. hrasdanicum (6x) of the Murina group have different heterozygous phenotypes of PGD, suggesting their alloploid nature. H. hrasdanicum reveals fixation of additional heterozygosity at two AAT loci. No accession of H. glaucum (2x) was found, fitting the donor of any of the genomes of H. murinum and H. hrasdanicum. The annuals of the series Marina differ distinctly from the Murina annuals of the section Trichostachys in some isoenzymes. They are removed from the section Trichostachys in a new section Marina (NEVSKI) JAASKA stat.nov. H. marinum ssp. gussoneanum tetraploids (= H. geniculalum auct.) show fixation of heterozygosity at two AAT loci, suggesting their alloploid nature. The outcrossing perennials H. bulbosum and H. brevisubulatum s. 1. show allozymic polymorphism of AAT-B and AAT-C, but are invariant in PGD-A. H. secalinum and H. jubatum share fixed heterozygosity of AAT-B, favouring their alloploid nature.