Isozyme similarity in <i>Thinopyrum</i> and its relatives (Triticeae: Gramineae)

Abstract

Thirty-seven alleles encoded by eight loci from six enzyme systems were numerically analyzed in taxa of Thinopyrum, Lophopyrum, Trichopyrum, and Pseudoroegneria. Thinopyrum and Lophopyrum were similar, and both were distant from Pseudoroegneria. This is consistent with anatomical and genomic evidence, but conflicts with that from morphology. The only extant diploid of Lophopyrum was isolated from other members of its genus. The data suggest that it may have diverged in terms of its isozymes subsequent to the differentiation of the E genome, and its incorporation into the extant alloploids or their ancestors. Alloploids between the E and S genomes showed isozyme patterns resembling those of Pseudoroegneria, reflecting patterns of variation shown by morphological and anatomical data. It is clear that an understanding of the evolutionary relationships in the taxa of Thinopyrum and its relatives requires synthesis of different kinds of evidence.Key words: Triticeae, genomes, isozymes, evolution, genetic resources.