In the face of climate change, optimization of almond irrigation management is critical for ensuring the longterm sustainability of nut production and water resources. To achieve optimal irrigation management, continuous monitoring of the plant water status is critical in scheduling irrigation. It is a widely accepted practice to use stem water potential (SWP) as a measure of plant water status in woody perennials like almonds. However, the pressure chamber (PC) commonly used to make these measurements is labor-intensive and does not provide continuous data without significant additional labor. In this study, we evaluated two recently developed stem water potential sensors (Microtensiometer [MT], and Osmotic Cell [OC]), both of which can measure the SWP nearly continuously when embedded in stem sapwood tissue (typically in the trunk or branch of a tree). SWP sensors were evaluated in nine commercial almond orchards in the Central Valley of California. The SWP values obtained from both sensors were compared to the values measured using a PC using statistical software called FITEVAL. Overall, sensor performance varied from good to acceptable and from acceptable to unacceptable for MT and OC sensors respectively. The MT sensors demonstrated higher accuracy with a Nash-Sutcliff Coefficient of Efficiency (NSE) of 0.84 (95 % CI: 0.78-0.88) and a Root Mean Square Error (RMSE) of -0.24 MPa (95 % CI: -0.21 to -0.28 MPa), while the OC sensor had an NSE of 0.68 (95 % CI: 0.61-0.74) and an RMSE of -0.32 MPa (95 % CI: -0.29 to -0.35 MPa). MT sensors exhibited the added advantage of providing sub-hourly data and displaying tree recovery from water stress following irrigation, positioning them as potentially superior for precision almond orchard water management. If widely adopted, SWP sensors have the potential to optimize water use in almond production.

Recent prolonged droughts in California have emphasized the urgent need to implement more efficient water management practices for high value tree crops. Accurate estimation of evapotranspiration (ET), a main component of consumptive water use, is critical for improving management of micro-irrigated pistachio orchards grown in the San Joaquin Valley of California. We estimated ET of three mature commercial pistachio orchards on non-saline and increasingly saline soils in 2015 and 2016, using the Mapping Evapotranspiration at high Resolution with Internalized Calibration (METRIC) method and Landsat 8 satellite observations. Based on a comparison with field observations at 8 sites, we modified the parameterizations of the momentum roughness length and net radiation for pistachio tree crops and reduced the uncertainty of daily ET estimates. When compared with field data, the recalibrated METRIC ET estimates had an R-2 of 0.59, a mean absolute error of 1.1 mm/day, and a RMSE of 1.4 mm/day during Landsat overpass dates (n = 72). The METRIC ET map captured the temporal dynamics and spatial heterogeneity both within and among the orchards. The mean annual crop season estimated ET (mid-March to mid-October in 2016) with remote sensing decreased by 32% from 1064 +/- 99 mm in the non-salt affected control orchard to 725 +/- 82 nun in the orchard with the highest level of soil-water salinity. The ET reduction was consistent with canopy volume differences among the study orchards, as shown by summer Normalized Difference Vegetation Index (NDVI) from Landsat observations, e.g., 0.72 +/- 0.06 in the control vs. 0.52 +/- 0.06 in the most saline orchard. The available energy was controlled mostly by canopy features and explained 64% of daily ET variation among all Landsat pixels and satellite overpass days. The normalized differenced water index (NDWI) could be considered as an important parameter to capture the partitioning of available energy for ET (R-2 = 0.38), suggesting that the lower soil osmotic potential in saline orchards further reduced crop ET.

Greater sage-grouse (Centrocercus urophasianus; sage-grouse) are a species of conservation concern throughout western North America. Obtaining valid population estimates is essential to understanding population trajectories and the effects of management. Counts of male sage-grouse attending leks during the breeding season are used directly as a population index or to estimate the breeding population size by assuming a detection probability and sex ratio. In the latter case, managers often assume a 2:1 female-biased ratio. However, this sex ratio has not been validated and may result in biased population estimates. We evaluated sex ratios at hatch, 42 days of age, and at harvest to determine if sex ratios were biased for sage-grouse in Utah. Sex ratios at hatch and at 42 days of age did not differ from parity. Harvest data suggested that sage-grouse may exhibit a slight female-biased sex ratio (1.458:1) in the fall. Wildlife management agencies should use caution when using lek count data to estimate population size if sex ratios have not been validated. (c) 2013 The Wildlife Society.

Basin wildrye [Leymus cinereus (Scribn. & Merr.) A. Love] and creeping wildrye [Leymus triticoides (Buckley) Pilg.] are outcrossing perennial grasses native to western North America. These divergent species are generally adapted to different habitats but can form fertile hybrids. Cultivars of both species are used in agriculture and conservation, but little is known about genetic diversity and gene flow among these species. Therefore, multilocus amplified fragment length polymorphism (AFLP) genotypes and chloroplast DNA sequences were evaluated from 536 L. cinereus and 43 L. triticoides plants from 224 locations of western United States and Canada. Bayesian-cluster analysis detected three L. cinereus races corresponding to the Columbia, Rocky Mountain, and Great Basin regions. Possible admixture between species was detected in specific areas, but only 2.2% of the plants showed more than 10% introgression. The Columbia and Great Basin races were predominantly octoploid whereas most of the Rocky Mountain accessions were tetraploid. Approximately 36 and 7% of the AFLP variation was apportioned among species and races, respectively, but no discrete marker differences were detected among these groups. Although species can be distinguished using a relatively small set of AFLP markers showing divergent allele frequencies, at least 30 markers were needed to classify plants by race. Approximately 8 and 11% of the chloroplast DNA sequence variation was apportioned among species and races, but these markers were not practically useful for species or race identification.

Leymus is a genomically defined allopolyploid of genus Triticeae with two distinct subgenomes. Chloroplast DNA sequences of Eurasian and North American species are distinct and polyphyletic. However, phylogenies derived from chloroplast and nuclear DNA sequences are confounded by polyploidy and lack of polymorphism among many taxa. The AFLP technique can resolve phylogenetic relationships between closely related species, with a curvilinear relationship expected between the proportion of shared bands and nucleotide substitution rate ( D ), up to about 0.100 D . The objective of this study was to compare D and phylogenetic relationships among 16 Leymus taxa, based on chloroplast DNA sequences and multi-locus AFLP genotypes. Estimates of chloroplast D between taxa were 0.002 and 0.013 within and among continental regions, respectively. Estimates of AFLP D between taxa were 0.076 and 0.093 compared within and between continental regions, respectively, versus 0.024 within taxa. Bayesian and neighbor-joining cluster analyses effectively separated all AFLP genotypes by species, but showed that North American L. ambiguus is a hybrid species with nearly equal contributions from sympatric L. cinereus and L. salinus taxa. Two hierarchical AFLP clades, containing six North American taxa and four Eurasian taxa, had more than 98% bootstrap confidence with 0.071 and 0.055 D among taxa. Three other Eurasian taxa clustered with 79% and 89% confidence, with up to 0.79 D between taxa. These estimates provide benchmarks for phylogenetic comparisons of AFLP profiles, but three taxa could not be reliably grouped, which may reflect concurrent radiation of multiple lineages or lack of homologous AFLP characters caused by a high D .

Lepidium papilliferum of southwest Idaho was previously treated as an infraspecific variety of Lepidium montanum. Chloroplast (cpDNA) sequences, nuclear ribosomal internal transcribed spacer (ITS) sequences, and AFLPs were used to test species delimitations and other possible evolutionarily significant units (ESU) based on genetic differentiation, isolation by distance (IBD), and genetic admixture among 32 L. montanum and 21 L. papilliferum collections from the western US. The L. papilliferum AFLP genotypes formed a monophyletic clade. However, the AFLP genotypes of L. montanum samples from eight western sites were more similar to L. papilliferum, which together comprise a regionally significant West clade showing significant differentiation from eastern L. montanum collections (East clade). Bayesian analysis of AFLP genotypes detected possible admixture between L. papilliferum and related western L. montanum collections. Neither taxa nor regionally significant AFLP clades displayed reciprocally monophyletic cpDNA or ITS sequences, but the AFLP clades showed stronger cpDNA differentiation and unique ITS alleles. The East and West clades fit models of speciation with relatively strong IBD within groups and weak IBD between groups, based on correlations between the average number of AFLP differences and geographic distances among collection sites, but comparisons between taxa did not fit this model. Conversely, relatively strong partial correlations between AFLP and taxonomic differences, controlling for geography, support taxonomic delimitations. Results suggest that L. papilliferum is a distinct subgroup of L. montanum influenced by speciation. However, gene flow or common ancestry between L. papilliferum and western forms of L. montanum provide a basis for other possible ESUs.

SMITH, J. F., A. J. STILLMAN (Department of Biological Sciences, Boise State University, Boise, ID 83725), STEVEN R. LARSON, C. MAE CULUMBER (USDA-ARS Forage and Range Research Laboratory, Utah State University, Logan, UT 84341), IAN C. ROBERTSON AND STEPHEN J. NOVAK (Department of Biological Sciences, Boise State University, Boise, ID 83725). Phylogenetic relationships among Lepidium papilliferum (L. Henderson) A. Nels. & J. F. Macbr., L. montanum Nutt., and L. davisii Rollins (Brassicaceae). J. Torrey Bot. Soc. 136: 149-163. 2009.-Previous phylogenetic analyses of Lepidium included only a few accessions of L. montanum, L. flavum, and L. fremontii to represent western North American species. Two additional species endemic to southwest Idaho have posed both taxonomic and conservation questions regarding their species status. Lepidium papilliferum was originally described as a variety of L. montanum, is morphologically similar to L. montanum, and is found in small scattered populations in southwest Idaho. The plant is restricted to specific edaphic conditions known as slick spots where high clay content creates conditions amenable to L. papilliferum, but to few other species. Resolving whether the populations of L. papilliferum merit species status distinct from L. montanum is a vexing question and phylogenetic analyses can assist in resolving this issue. Like L. papilliferum, L. davisii has specific edaphic requirements and is found in playas, areas similar to slick spots, but larger and with deeper soils. Unlike L. papilliferum, L. davisii is morphologically distinct from L. montanum and has posed less of a taxonomic quandary. Previous phylogenetic studies have shown that American species of Lepidium are derived from an ancestral allopolyploid species. In this study we have expanded previous analyses to include L. papilliferum, L. davisii, and several accessions of L. montanum along with published sequences of ITS, cpDNA, and PISTILLATA first intron. The western North American species form a monophyletic group with L. davisii sister to the remainder of the clade. Within this clade, L. papilliferum and L. fremontii are each monophyletic and sister to each other, but are imbedded within a paraphyletic L. montanum.