Ecotypic Variation in Selected Fourwing Saltbush Populations in Western Texas

Abstract

Fourwing saltbush [A tr@kx cmescens (Pursh) Nutt.] seedlings from 4 western Texas tetraploid populations were established in uniform nurseries at San Angelo, Barnhart, and Marfa, Texas, in 1981 to determine relative adaptability to these respective environments. Survival and canopy development of the ecotypes were similar at the site with the most favorable growing conditions (San Angelo), but the ecotype originating nearest the planting site tended to have greatest survival and canopy size where site conditions were less favorable. Additional shrub attributes evaluated at the !3an Angelo site included: leaf, current year's stem, and wood phytomass, seasonal nutrient concentrations, and floral develop ment and phenotype. prediction equations utilizing plant canopy measurements were used to estimate weights of plant components. Variation in canopy size and yields among individual plants within ecotypes masked detection of significant (PrO.05) differences among ecotypes, but ecotypes from arid environments tended to be larger and to have greater yields than those from more mesic environments. Concentrations of crude protein (CP), phosphorus (P), and digestible organic matter (DOM)of leaves and stems were similar among the 4 ecotypes. Floral development of the ecotype from the most mesic environment progressed at a faster rate than that of ecotypes from more xeric environments. Ecotypes from xeric environments tended to have fewer staminate plants, but more plants with no sex expression than ecotypes from more mesic areas.

Na and K Accumulation and Salt Tolerance of Atriplex canescens (Chenopodiaceae) Genotypes

“…It grows in soils ranging in texture from dune sand to heavy clay and under salinity regimes ranging from nonsaline to seawater-saturated soil in the intertidal zone of desert estuaries (Glenn et al, 1994). The ability of A. canescens to occupy so many xeric and saline niches has been attributed to genetic diversity within the species (Sanderson and Stutz, 1994); it is composed of at least six varieties or subspecies differing in ploidy level (Sanderson and Stutz, 1994), plus numerous ecotypes that have not been genetically defined (e.g., Petersen et al, 1987).…”

Characterizing Gene Responses to Drought Stress in Fourwing Saltbush [Atriplex canescens (Pursh.) Nutt.]

“…If homology is not established between the species, it could indicate that the response observed and/ or the clones are perhaps unique to fourwing saltbush. This same approach can be used to determine if unique clones are associated with drought-tolerant and droughtsensitive ecotypes of Atriplex as described by other investigators using other criteria (Van Epps 1975, McArthur et al 1983, Petersen et al 1987. This report indicates how molecular biology can be used to characterize drought responses of Atriplexat the basic, fundamental level of the gene.…”

“…Diploids are found on the harsher sites with coarse sandy soils and sand dune areas, whereas tetraploids seem better adapted to the silty clay flood plains of rivers (Dunford 1984). Ecotypic variation among fourwing saltbush populations has been documented (McArthur et al 1983, Potter et al 1986) with ecotypes originating from harsh environments having a wider range of adaptation than those originating from more favorable environments (Van Epps 1975, McArthur et al 1983, Petersen et al 1987).…”

Selective-Placement Burial of Drilling Fluids: Effects on Soil Properties, Buffalograss and Fourwing Saltbush after 4 Years

“…One or 2 fourwing saltbush plants from each subplot were harvested to 10 cm above ground level and oven-dried at 60? C. The biomass and canopy height and diameter data were used to develop regression equations for estimating aboveground biomass (Peterson et al 1987). Standing crops of buffalograss were estimated by harvesting to ground line in 10, equidistantly-spaced, 0.25-iM2 quadrats in each subplot.…”