Abstract: | Two molecular marker systems, random amplified polymorphic DNA (RAPD) and microsatellites, were used to evaluate population diversity and differentiation in 4 northern Nevada Bromus tectorum populations. From 80 RAPD primers, we found 16 (20%) that yielded 165 strong repeatable bands. Of those bands, 60 (35.8%) were polymorphic. Of those, 21 met data-pruning guidelines for final analysis. RAPD variation was moderate (0.363, SE = 0.022), ranging from 0.312 to 0.404. Microsatellite variation was similar (0.234, SE = 0.051) but varied more widely, ranging from 0.009 to 0.551. All populations were out of Hardy-Weinberg equilibrium, as expected in a predominantly selfing species. RAPDs revealed significant differentiation (P Bromus rubens ). |