scholarly journals Further examination of the geographic range of Eriogonum corymbosum var. nilesii (Polygonaceae, Eriogoneae)

Phytotaxa ◽  
2015 ◽  
Vol 203 (3) ◽  
pp. 289 ◽  
Author(s):  
Mark Winston Ellis ◽  
Paul Gilead Wolf ◽  
Shannon Bardot ◽  
James Walton ◽  
Carol Rowe ◽  
...  
Keyword(s):  
United States ◽  
Genetic Variation ◽  
Mojave Desert ◽  
Geographic Range ◽  
Wild Buckwheat ◽  
Desert Region ◽  
Northern Arizona ◽  
Southern Nevada ◽  
Extended Range ◽  
Eriogonum Corymbosum

The wild buckwheat Eriogonum corymbosum is widely distributed throughout the southwestern United States, forming a complex of eight varieties. E. corymbosum var. nilesii is a predominantly yellow-flowered variant reported primarily from Clark Co., Nevada. A previous genetic study by our research group found that var. nilesii is genetically distinct from other E. corymbosum varieties, based on a limited number of populations. Here, we assess genetic variation in 14 newly sampled yellow-flowered populations from southern Nevada, southern Utah, and northern Arizona, and compare them to genetic variation in six populations of previously determined E. corymbosum varieties. Of the new populations, we identified four as var. nilesii, four as var. aureum, three as var. glutinosum, two as apparent hybrids involving vars. aureum and nilesii, and one as a more distantly related admixture involving E. thompsoniae. Our results extend the range and area of E. corymbosum var. nilesii considerably from that traditionally stated in the literature. However, this extended range is confined to the Mojave Desert region of southern Nevada, and the number of known populations remains limited.

scholarly journals Genetic Diversity of Lowbush Blueberry throughout its U.S. Native Range in Managed and Non-managed Populations

2019 ◽  
Author(s):  
Lee Beers ◽  
Jeannie Rowland ◽  
Francis Drummond
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Polymerase Chain Reaction ◽  
Genetic Variation ◽  
Geographic Range ◽  
Eastern United States ◽  
Native Range ◽  
Chain Reaction ◽  
Lowbush Blueberry ◽  
Polymerase Chain

Expressed sequenced tagged-polymerase chain reaction (EST-PCR) molecular markers were used to evaluate the genetic diversity of lowbush blueberry across its geographic range and to compare genetic diversity among four paired managed/non-managed populations. Seventeen lowbush blueberry populations were sampled in a general north south transect throughout eastern United States with distances between 27 km to 1600 km separating populations. Results show that the majority of genetic variation is found within populations (75%) versus among populations (25%), and that each population was genetically unique (P ≤ 0.0001) with the exception of the Jonesboro, ME and Lubec, ME populations that were found not to be significantly different (P = 0.228). The effects of management for commercial fruit harvesting on genetic diversity were investigated in four locations in Maine with paired managed and non-managed populations. Significant differences were found between the populations indicating that commercial management influences the genetic diversity of lowbush blueberries in the landscape, despite the fact that planting does not occur; forests are harvested and the existing understory blueberry plants are what become established.

The Pinto shear zone; a Laramide synconvergent extensional shear zone in the Mojave Desert region of the southwestern United States

2005 ◽  
Vol 27 (9) ◽  
pp. 1697-1720 ◽  
Author(s):  
Michael L. Wells ◽  
Mengesha A. Beyene ◽  
Terry L. Spell ◽  
Joseph L. Kula ◽  
David M. Miller ◽  
...  
Keyword(s):  
United States ◽  
Shear Zone ◽  
Mojave Desert ◽  
Southwestern United States ◽  
Desert Region

scholarly journals A Survey of Genetic Variation in Streptomyces Isolates Causing Potato Common Scab in the United States

2006 ◽  
Vol 96 (12) ◽  
pp. 1363-1371 ◽  
Author(s):  
Leslie A. Wanner
Keyword(s):  
United States ◽  
Genetic Variation ◽  
Common Scab ◽  
Disease Incidence ◽  
The United States ◽  
Rrna Gene ◽  
Population Genetic Study ◽  
Variable Regions ◽  
Genus Streptomyces ◽  
Characteristic Features

Common scab is a serious disease of potatoes and other root and tuber crops, affecting crop quality and market value. The disease is caused by gram positive soil bacteria in the genus Streptomyces. Disease incidence and severity vary in different locations and years; this is due in part to variation in the environment (weather) and genetic variation in potato cultivars. Little information is available on the contribution of genetic variation by the pathogen. To examine genetic diversity in different locations within the United States, streptomycetes were isolated from lesions on field-grown potatoes from six states. Isolates were classified into species based on sequence of variable regions in the 16s rRNA gene. The presence of genes associated with the recently described S. turgidiscabies pathogenicity island (PAI) was also determined. About half of the isolates belonged to S. scabies or S. europaeiscabiei based on 16s rDNA sequence, and had characteristic features of the PAI. They were found in all six states, and were pathogenic on potato and radish. The remaining isolates included pathogens and nonpathogens. They were varied in appearance, and represent several species, including one pathogenic species not previously reported. Some pathogenic isolates lacked one or more genes characteristic of the PAI, although all had genes for biosynthesis of the pathogenicity determinant thaxtomin. In this relatively small survey, regional differences in scab-causing streptomycetes were seen. This report furnishes tools and baseline data for population genetic study of scab-causing streptomycetes in the United States.

scholarly journals Genetic Variation of Sclerotinia sclerotiorum from Multiple Crops in the North Central United States

PLoS ONE ◽  
2015 ◽  
Vol 10 (9) ◽  
pp. e0139188 ◽  
Author(s):  
Laura Aldrich-Wolfe ◽  
Steven Travers ◽  
Berlin D. Nelson
Keyword(s):  
United States ◽  
Genetic Variation ◽  
Sclerotinia Sclerotiorum ◽  
North Central ◽  
The North ◽  
Central United States

Genetic variation and evolutionary relationships amongst bluetongue viruses endemic in the United States

1991 ◽  
Vol 21 (2) ◽  
pp. 91-109 ◽  
Author(s):  
H.W. Heidner ◽  
L.G. Iezzi ◽  
B.I. Osburn ◽  
N.J. MacLachlan
Keyword(s):  
United States ◽  
Genetic Variation ◽  
The United States ◽  
Evolutionary Relationships

Impacts on ecosystems, corrective restoration practices, and prospects for recovery: nine case studies in the continental United States

2017 ◽  
Vol 39 (6) ◽  
pp. 431 ◽  
Author(s):  
T. A. Jones
Keyword(s):  
United States ◽  
Ecosystem Services ◽  
Chesapeake Bay ◽  
Case Studies ◽  
Great Basin ◽  
Mojave Desert ◽  
Flood Control ◽  
Colorado River ◽  
Longleaf Pine ◽  
Elwha River

Ecological restoration in the United States is growing in terms of the number, size, and diversity of projects. Such efforts are intended to ameliorate past environmental damage and to restore functioning ecosystems that deliver desired levels of ecosystem services. In nine current restoration case studies from across the continental United States, this paper details (1) the impacts of the original disturbance and compounding secondary issues that compel restoration, (2) the corrective practices applied to advance restoration goals, and (3) the prospects for recovery of ecosystem services, including those involving associated animal populations. Ecosystem-altering impacts include flood control (Kissimmee River), flood control and navigation (Atchafalaya Basin), damming for irrigation-water storage (Colorado River) and hydroelectric power (Elwha River), logging and fire suppression (longleaf pine forest), plant invasions that decrease fire-return intervals (Great Basin shrublands, Mojave Desert), nutrient and sediment loading of watersheds (Chesapeake Bay, Mississippi River delta), and conversion of natural lands to agriculture (tallgrass prairie). Animal species targeted for recovery include the greater sage-grouse (Great Basin shrublands), the red-cockaded woodpecker (longleaf pine forest), the south-western willow flycatcher (Colorado River and its tributaries), the desert tortoise (Mojave Desert), eight salmonid fish (Elwha River), and the blue crab and eastern oyster (Chesapeake Bay).

scholarly journals Precipitation Prediction Skill for the West Coast United States: From Short to Extended Range

2018 ◽  
Vol 32 (1) ◽  
pp. 161-182 ◽  
Author(s):  
Baoxiang Pan ◽  
Kuolin Hsu ◽  
Amir AghaKouchak ◽  
Soroosh Sorooshian ◽  
Wayne Higgins
Keyword(s):  
United States ◽  
West Coast ◽  
El Niño ◽  
El Nino ◽  
The United States ◽  
Prediction Skill ◽  
Precipitation Prediction ◽  
Skill Scores ◽  
Extended Range ◽  
To Receive

Abstract Precipitation variability significantly influences the heavily populated West Coast of the United States, raising the need for reliable predictions. We investigate the region’s short- to extended-range precipitation prediction skill using the hindcast database of the Subseasonal-to-Seasonal Prediction Project (S2S). The prediction skill–lead time relationship is evaluated, using both deterministic and probabilistic skill scores. Results show that the S2S models display advantageous deterministic skill at week 1. For week 2, prediction is useful for the best-performing model, with a Pearson correlation coefficient larger than 0.6. Beyond week 2, predictions generally provide little useful deterministic skill. Sources of extended-range predictability are investigated, focusing on El Niño–Southern Oscillation (ENSO) and the Madden–Julian oscillation (MJO). We found that periods of heavy precipitation associated with ENSO are more predictable at the extended range period. During El Niño years, Southern California tends to receive more precipitation in late winter, and most models show better extended-range prediction skill. On the contrary, during La Niña years Oregon tends to receive more precipitation in winter, with most models showing better extended-range skill. We believe the excessive precipitation and improved extended-range prediction skill are caused by the meridional shift of baroclinic systems as modulated by ENSO. Through examining precipitation anomalies conditioned on the MJO, we verified that active MJO events systematically modulate the area’s precipitation distribution. Our results show that most models do not represent the MJO or its associated teleconnections, especially at phases 3–4. However, some models exhibit enhanced extended-range prediction skills under active MJO conditions.

scholarly journals Measurement of Genetic Diversity of Chinese Seashore Paspalum Resources through Morphological and Sequence-related Amplified Polymorphism Analysis

2019 ◽  
Vol 144 (6) ◽  
pp. 379-386
Author(s):  
Yan Liu ◽  
Hailin Guo ◽  
Yi Wang ◽  
Jingang Shi ◽  
Dandan Li ◽  
...  
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Cluster Analysis ◽  
Genetic Variation ◽  
Genetic Distance ◽  
Morphological Characteristics ◽  
The United States ◽  
Germplasm Resources ◽  
Seashore Paspalum ◽  
Chinese Germplasm

Seashore paspalum (Paspalum vaginatum) is a notable warm-season turfgrass. Certain germplasm resources are distributed in the southern regions of China. The objectives of this study were to investigate the genetic diversity and genetic variation of Chinese seashore paspalum resources. Morphological characteristics and sequence-related amplified polymorphism (SRAP) markers were used to assess genetic relationships and genetic variation among 36 germplasm resources from China and six cultivars from the United States. The results showed significant variation for 13 morphological characteristics among 42 tested seashore paspalum accessions, and that the phenotypic cv was, in turn, turf height > turf density > internode length > inflorescence density > leaf width > reproductive branch height > spikelet width > leaf length > spikelet number > inflorescence length > internode diameter > inflorescence width > spikelet length. According to the morphological characteristics and cluster analysis, 42 seashore paspalum accessions were divided into six morphological types. In total, 374 clear bands were amplified using 30 SRAP primer combinations; among these bands, 321 were polymorphic with 85.83% polymorphism. SRAP marker cluster analysis showed that 42 seashore paspalum accessions were grouped into seven major groups, with a genetic similarity coefficient ranging from 0.4385 to 0.9893 and genetic distance values ranging from 0.0108 to 0.8244. The high level of genetic diversity occurred among Chinese germplasm, and the genetic distance was relatively high between Chinese germplasm and cultivars introduced from the United States. The patterns in morphological trait variations and genetic diversity will be useful for the further exploitation and use of Chinese seashore paspalum resources.

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