Allozyme Diversity and Interspecific Differentiation of the Two Diploid Bromegrass Species, Bromus tectorum L. and B. sterilis L. (Poaceae)

Abstract

Genetic diversity among 50 accessions of Bromus tectorum and 43 of B. sterilis from different sites of their Eurasian ranges has been studied by electrophoretic analysis of ten enzymes encoded by 18 loci. The two species proved clearly differentiated by alternate allozymes at seven isozymes. Populations of both taxa showed differentiation into eleven (B. tectorum) and six (B. sterilis) multilocus allozyme lineages (MLALs). The extent of interspecific allozyme divergence estimated by Manhattan distance exceeded more than three times intraspecific differentiation between the multilocus lineages. Only two MLALs in each species have wide geographical distribution from the Near East to Europe. Other MLALs were found each for only one or two populations and were region-specific. Most geographically marginal European populations had widespread MLALs.

Key words

Bromus - Poaceae - isozymes - allozyme diversity - geographic distribution