We investigated the frequency of outcrossing in downy brome (Bromus tectorum L.), a cleistogamous weedy annual grass, in both common garden and wild populations, using microsatellite and single nucleotide polymorphic (SNP) markers. In the common garden study, 25 lines with strongly contrasting genotypes were planted in close proximity. We fingerprinted 10 seed progeny from 8 individuals of each...

Bradley N. Johnson Tami L. Stubbs Land Management and Water Conservation Research Unit, USDA Agricultural Research Service, 215 Johnson Hall, Washington State University, Pullman, WA, 99164-6421 Pseudomonas fluorescens strain D7 (P. f. D7; NRRL B-18293) is a root-colonizing bacterium that inhibits downy brome (Bromus tectorum L. BROTE) growth. Before commercialization as a biological control ag...

Temperature and water potential strongly influence seed dormancy status and germination of Bromus tectorum. As seeds of this plant can be killed by the ascomycete fungus Pyrenophora semeniperda, this study was conducted to learn how water potential and temperature influence mortality levels in this pathosystem. Separate experiments were conducted to determine: (1) if P. semeniperda can kill dor...

Managers reduce piñon (Pinus spp.) and juniper (Juniperus spp.) trees that are encroaching on sagebrush (Artemisia spp.) communities to lower fuel loads and increase cover of desirable understory species. All plant species in these communities depend on soil water held at . 1.5 MPa matric potential in the upper 0.3 m of soil for nutrient diffusion to roots and major growth in spring (resource g...

Cheatgrass (Bromus tectorum) is an invasive weed in western North America found primarily growing at elevations less than 2200 m. We asked whether cheatgrass is capable of becoming adapted to a marginal habitat, by investigating a population at a high elevation invasion edge. We used a combination of methods, including reciprocal field transplants, controlled environment studies and molecular a...

Cheatgrass (Bromus tectorum) is of growing concern among farmers, ranchers, and researchers in the intermountain west due to its ability to alter rangeland vegetation communities and their associated fire regimes. Quickbird multi-spectral imagery (spatial resolution 2.4 mpp) was used to detect and model cheatgrass presence in southeastern Idaho. Training sites were created using 2003 field data...

Although cheatgrass (Bromus tectorum) has been widely distributed across western rangelands for >70 years, the full ecologic and economic impacts of this non-native invasive plant have not yet occurred. Unfortunately, several independent lines of evidence indicate that the rate at which acreage becomes infested with cheatgrass is increasing rapidly. Furthermore, the invasion and spread of a num...