Emergence Dynamics of Kochia (Kochia scoparia) Populations from the U.S. Great Plains: A Multi-Site-Year Study

Weed Science ◽  
2017 ◽  
Vol 66 (1) ◽  
pp. 25-35 ◽  
Author(s):  
Vipan Kumar ◽  
Prashant Jha ◽  
J. Anita Dille ◽  
Phillip W. Stahlman
Keyword(s):  
New Mexico ◽  
Great Plains ◽  
Field Experiments ◽  
Emergence Period ◽  
Emergence Pattern ◽  
The North ◽  
Rate Of Emergence ◽  
Sites Of Action ◽  
Rapid Emergence ◽  
The U.S

Evolution of kochia biotypes resistant to multiple herbicide sites of action is an increasing concern for growers across the U.S. Great Plains. This necessitates the development of integrated strategies for kochia control in this region based on improved forecasting of periodicity and patterns of kochia emergence in the field. Field experiments were conducted near Huntley, MT, in 2013 and 2014, and in Manhattan and Hays, KS, in 2013 to characterize the timing and pattern of emergence of several kochia populations collected from the U.S. Great Plains’ states. The more rapid accumulation of growing degree days (GDD) resulted in a shorter emergence duration (E90–E10) in 2014 compared with 2013 in Montana. Kochia populations exhibited an extended emergence period (early April through mid-July). Among all kochia populations, in 2013, Kansas-Garden City (KS-GC), Kansas-Manhattan (KS-MN), Oklahoma (OK), and Montana (MT) populations began to emerge earlier, with a minimum of 151 cumulative GDD to achieve 10% cumulative emergence (E10values) in Montana. The New Mexico-Los Lunas (NM-LL) population exhibited a delayed onset but a rapid emergence rate, while the North Dakota (ND) and Kansas-Colby (KS-CB) populations emerged over a longer duration (E90–E10of 556 and 547 GDD, respectively) in 2013 in Montana. In 2013 at the two locations in Kansas, kochia populations exhibited a similar emergence pattern, with no differences in the time to initiate germination (E10), rate of emergence (parameterb), or duration of emergence (E90–E10). At Hays, KS, the GDD for E50and E90were less for ND compared with KS-MN and KS-GC local populations. In 2014 the KS-MN kochia population exhibited an early (ED10value of 215 GDD) but a more gradual emergence pattern (E90–E10=526 GDD) in Montana. In contrast, OK and New Mexico-Las Cruces (NM-LC) populations had an early and a more rapid emergence pattern (E90–E10=153 and 154 GDD, respectively). Kochia in Montana exhibited two to four emergence peaks. This differential emergence pattern of kochia populations reflects the occurrence of different emergence “biotypes” and emphasizes the need to adopt more location-specific and diversified weed control tactics to manage kochia seedbanks.

scholarly journals Quantifying the Land–Atmosphere Coupling Behavior in Modern Reanalysis Products over the U.S. Southern Great Plains

2015 ◽  
Vol 28 (14) ◽  
pp. 5813-5829 ◽  
Author(s):  
Joseph A. Santanello ◽  
Joshua Roundy ◽  
Paul A. Dirmeyer
Keyword(s):  
Soil Moisture ◽  
Great Plains ◽  
Southern Great Plains ◽  
Diurnal Cycles ◽  
The North ◽  
Energy Cycle ◽  
Coupling Behavior ◽  
Regional Reanalysis ◽  
Modern Era ◽  
The U.S

Abstract The coupling of the land with the planetary boundary layer (PBL) on diurnal time scales is critical to regulating the strength of the connection between soil moisture and precipitation. To improve understanding of land–atmosphere (L–A) interactions, recent studies have focused on the development of diagnostics to quantify the strength and accuracy of the land–PBL coupling at the process level. In this paper, the authors apply a suite of local land–atmosphere coupling (LoCo) metrics to modern reanalysis (RA) products and observations during a 17-yr period over the U.S. southern Great Plains. Specifically, a range of diagnostics exploring the links between soil moisture, evaporation, PBL height, temperature, humidity, and precipitation is applied to the summertime monthly mean diurnal cycles of the North American Regional Reanalysis (NARR), Modern-Era Retrospective Analysis for Research and Applications (MERRA), and Climate Forecast System Reanalysis (CFSR). Results show that CFSR is the driest and MERRA the wettest of the three RAs in terms of overall surface–PBL coupling. When compared against observations, CFSR has a significant dry bias that impacts all components of the land–PBL system. CFSR and NARR are more similar in terms of PBL dynamics and response to dry and wet extremes, while MERRA is more constrained in terms of evaporation and PBL variability. Each RA has a unique land–PBL coupling that has implications for downstream impacts on the diurnal cycle of PBL evolution, clouds, convection, and precipitation as well as representation of extremes and drought. As a result, caution should be used when treating RAs as truth in terms of their water and energy cycle processes.

Backcrossing Provides an Avenue for Gene Introgression from Wheat to Jointed Goatgrass (Aegilops cylindrica) in the U.S. Great Plains

Weed Science ◽  
2011 ◽  
Vol 59 (2) ◽  
pp. 188-194 ◽  
Author(s):  
Bethany F. Econopouly ◽  
John K. McKay ◽  
Philip Westra ◽  
Nora L. V. Lapitan ◽  
Phillip L. Chapman ◽  
...  
Keyword(s):  
Gene Flow ◽  
Great Plains ◽  
Field Experiments ◽  
Transgenic Wheat ◽  
Gene Introgression ◽  
Wheat Cultivars ◽  
Jointed Goatgrass ◽  
Hybrid Plants ◽  
Recurrent Backcrossing ◽  
The U.S

Jointed goatgrass is an exotic species introduced into the western United States from Eurasia. The weed is an agricultural pest infesting winter wheat fields and causing economic loss. Common ancestry between the two species enables interspecific hybridization, thus providing a mechanism for gene flow to occur. This can facilitate the accumulation of novel genes, which could increase the wild species' competitiveness with wheat and its ability to invade novel habitats. Interest in the development of transgenic wheat cultivars has increased the concern for interspecific gene flow. Gene introgression requires recurrent backcrossing to the weedy species after the initial hybridization event. Field experiments were conducted at two locations in Colorado in 2007–2008 and 2008–2009, with jointed goatgrass acting as the sole source of viable pollen for fertilization of transplanted hybrid plants. Backcrossing rates were determined by conducting germination studies on spikes collected from a total of 206 hybrid plants. Pollination by jointed goatgrass led to the production of 463 BC1plants from seed produced on these 206 hybrid plants. Ninety-five percent confidence intervals estimate the rate of backcrossing at 0.028 to 0.306% and 0.077 to 0.604%, with medians of 0.062 and 0.152%, respectively, at the two locations. The results demonstrate that backcrossing to jointed goatgrass can occur, despite low rates of hybrid fertility. Subsequent backcrossing would make it likely that a wheat gene conferring a selective advantage will introgress into the weedy population. For the U.S. Great Plains, it is possible that transgenic wheat cultivars will be released in the future and determining proper management of these cultivars is necessary to minimize hybridization and advantageous gene introgression into weedy relatives.

Emergence Pattern and Periodicity of Palmer Amaranth (Amaranthus palmeri) Populations from Southcentral Great Plains

2021 ◽  
pp. 1-21
Author(s):  
Rui Liu ◽  
Vipan Kumar ◽  
Prashant Jha ◽  
Phillip W. Stahlman
Keyword(s):  
Great Plains ◽  
Prediction Models ◽  
Agricultural Research ◽  
Control Strategies ◽  
Growing Season ◽  
Palmer Amaranth ◽  
Effective Control ◽  
Emergence Period ◽  
Emergence Pattern ◽  
Growing Seasons

Evolution of multiple herbicide-resistant Palmer amaranth warrants the development of integrated strategies for its control in the Southcentral Great Plains (SGP). In order to develop effective control strategies, an improved understanding of the emergence biology of Palmer amaranth populations from the SGP region is needed. A common garden study was conducted in a no-till (NT) fallow field at Kansas State University Agricultural Research Center near Hays, KS, during 2018 and 2019 growing seasons, to determine the emergence pattern and periodicity of Palmer amaranth populations collected from the SGP region. Nine Palmer amaranth populations collected from five states in the SGP region: Colorado (CO1, CO2), Oklahoma (OK), Kansas (KS1, KS2), Texas (TX), and Nebraska (NE1, NE2, NE3) were included. During the 2018 growing season, the CO1 and KS1 populations displayed more rapid emergence rates, with greater parameter b values (−5.4, and −5.3, respectively), whereas the TX and NE3 populations had the highest emergence rates (b = −12.2) in the 2019 growing season. The cumulative growing degree days (cGDD) required to achieve 10%, 50%, and 90% cumulative emergence ranged from 125 to 144, 190 to 254, and 285 to 445 in 2018 and 54 to 74, 88 to 160, and 105 to 420 in the 2019 growing season across all tested populations, respectively. The OK population exhibited the longest emergence duration (301 and 359 cGDD) in both growing seasons. All tested Palmer amaranth populations had peak emergence period between May 11 and June 8 in 2018, and April 30 and June 1 in the 2019 growing season. Altogether, these results indicate the existence of differential emergence pattern and peak emergence periods of geographically-distant Palmer amaranth populations from the SGP region. This information will help in developing prediction models for decision-making tools to manage Palmer amaranth in the region.

Dicamba-resistant kochia (Bassia scoparia) in Kansas: characterization and management with fall- or spring-applied PRE herbicides

2019 ◽  
Vol 33 (2) ◽  
pp. 342-348
Author(s):  
Vipan Kumar ◽  
Ryan P. Engel ◽  
Randall Currie ◽  
Prashant Jha ◽  
Phillip W. Stahlman ◽  
...  
Keyword(s):  
Great Plains ◽  
Field Experiments ◽  
Field Studies ◽  
Early Spring ◽  
Garden City ◽  
The Us ◽  
Sites Of Action ◽  
Summer Fallow ◽  
Us Great Plains ◽  
Fallow Phase

AbstractDicamba-resistant (DR) kochia is an increasing concern for growers in the US Great Plains, including Kansas. Greenhouse and field experiments (Garden City and Tribune, KS, in the 2014 to 2015 growing season) were conducted to characterize the dicamba resistance levels in two recently evolved DR kochia accessions collected from fallow fields (wheat–sorghum–fallow rotation) near Hays, KS, and to determine the effectiveness of various PRE herbicide tank mixtures applied in fall or spring prior to the fallow year. Dicamba dose–response studies indicated that the KS-110 and KS-113 accessions had 5- to 8-fold resistance to dicamba, respectively, relative to a dicamba-susceptible (DS) accession. In separate field studies, atrazine-based PRE herbicide tank mixtures, dicamba + pendimethalin + sulfentrazone, and metribuzin + sulfentrazone when applied in the spring had excellent kochia control (85% to 95%) for 3 to 4 mo at the Garden City and Tribune sites. In contrast, kochia control with those PRE herbicide tank mixtures when applied in the fall did not exceed 79% at the later evaluation dates. In conclusion, the tested kochia accessions from western Kansas had evolved moderate to high levels of resistance to dicamba. Growers should utilize these effective PRE herbicide tank mixtures (multiple sites of action) in early spring to manage kochia seed bank during the summer fallow phase of this 3-yr crop rotation (wheat–corn/sorghum–fallow) in the Central Great Plains.

scholarly journals Integrating cover crops for weed management in the semiarid U.S. Great Plains: opportunities and challenges

Weed Science ◽  
2020 ◽  
Vol 68 (4) ◽  
pp. 311-323
Author(s):  
Vipan Kumar ◽  
Augustine Obour ◽  
Prashant Jha ◽  
Rui Liu ◽  
Misha R. Manuchehri ◽  
...  
Keyword(s):  
Great Plains ◽  
Herbicide Resistance ◽  
Cover Crops ◽  
Weed Management ◽  
Management Practices ◽  
Cropping Systems ◽  
Health Improvement ◽  
Sites Of Action ◽  
The U.S

AbstractThe widespread evolution of herbicide resistance in weed populations has become an increasing concern for no-tillage (NT) growers in semiarid regions of the U.S. Great Plains. Lack of cost-effective and alternative new herbicide sites of action further exacerbates the problem of herbicide-resistant (HR) weeds and threatens the long-term sustainability of prevailing cropping systems in the region. A recent decline in commodity prices and increasing herbicide costs to manage HR weeds has spurred research efforts to build a strong rationale for developing ecologically based integrated weed management (IWM) strategies in the U.S. Great Plains. Integration of cover crops (CCs) in NT dryland production systems potentially offers several ecosystem services, including weed control, soil health improvement, decline in selective pest pressure, and overall reduction in pest management inputs. This review article aims to document the role of CCs for IWM, with emphasis on exploring emerging weed issues; ecological, economic, and agronomic benefits of growing CCs; and constraints preventing adoption of CCs in NT cropping systems in the semiarid Great Plains. We attempt to focus on changes in weed management practices, their long-term impacts on weed seedbanks, weed shifts, and herbicide-resistance evolution in the most common weed species in the region. We also highlight current knowledge gaps and propose new research priorities based on an improved understanding of CC management strategies that will ultimately aid in achieving sustainable weed management goals and preserving natural resources in water-limited environments.

scholarly journals Herbicide-Resistant Kochia (Bassia scoparia) in North America: A Review

Weed Science ◽  
2018 ◽  
Vol 67 (1) ◽  
pp. 4-15 ◽  
Author(s):  
Vipan Kumar ◽  
Prashant Jha ◽  
Mithila Jugulam ◽  
Ramawatar Yadav ◽  
Phillip W. Stahlman
Keyword(s):  
Great Plains ◽  
Herbicide Resistance ◽  
Cover Crops ◽  
North American ◽  
Weed Management ◽  
Evolutionary Dynamics ◽  
Integrated Weed Management ◽  
Herbicide Resistant ◽  
The North ◽  
Sites Of Action

AbstractKochia [Bassia scoparia(L.) A. J. Scott] is a problematic annual broadleaf weed species in the North American Great Plains.Bassia scopariainherits unique biological characteristics that contribute to its propensity to evolve herbicide resistance. Evolution of glyphosate resistance inB. scopariahas become a serious threat to the major cropping systems and soil conservation practices in the region.Bassia scopariapopulations with resistance to four different herbicide sites of action are a concern for growers. The widespread occurrence of multiple herbicide–resistant (HR)B. scopariaacross the North American Great Plains has renewed research efforts to devise integrated weed management strategies beyond herbicide use. In this review, we aim to compile and document the growing body of literature on HRB. scopariawith emphasis on herbicide-resistance evolutionary dynamics, distribution, mechanisms of evolved resistance, agronomic impacts, and current/future weed management technologies. We focused on ecologically based, non-herbicidal strategies such as diverse crop rotations comprising winter cereals and perennial forages, enhanced crop competition, cover crops, harvest weed seed control (HWSC), and tillage to manage HRB. scopariaseedbanks. Remote sensing using hyperspectral imaging and other sensor-based technologies would be valuable for early detection and rapid response and site-specific herbicide resistance management. We propose research priorities based on an improved understanding of the biology, genetic diversity, and plasticity of this weed that will aid in preserving existing herbicide resources and designing sustainable, integrated HRB. scopariamitigation plans.

THE RELATIONSHIP BETWEEN LATITUDE AND THE EMERGENCE OF ALFALFA LEAFCUTTER BEES, MEGACHILE ROTUNDATA (HYMENOPTERA: MEGACHILIDAE)

1980 ◽  
Vol 112 (6) ◽  
pp. 555-558 ◽  
Author(s):  
P. Pankiw ◽  
J. A. C. Lieverse ◽  
B. Siemens
Keyword(s):  
Cold Treatment ◽  
Western Canada ◽  
Megachile Rotundata ◽  
The South ◽  
Emergence Period ◽  
Emergence Pattern ◽  
Southern Latitude ◽  
The North ◽  
Northern Latitudes ◽  
The Relationship

AbstractStudies in Western Canada from 1974 to 1977 on variations in time and duration of the emergence period after diapause of leafcutter bees, Megachile rotundata (Fabricius), reared at latitudes ranging from 49°N to 58°N showed that bees reared at northern latitudes emerged sooner and the duration of the emergence period was shorter than for bees from the southern latitude. When southern bees were reared in the north, their emergence pattern was similar to the northern strain. However, the change of time to emerge and duration of emergence period of northern strains reared in the south was less pronounced. Number of days to emerge varied inversely with length of cold treatment at 4 °C with greater variance in southern strains.

scholarly journals Dynamical and Thermodynamical Causes of Large-Scale Changes in the Hydrological Cycle over North America in Response to Global Warming*

2014 ◽  
Vol 27 (20) ◽  
pp. 7921-7948 ◽  
Author(s):  
Richard Seager ◽  
David Neelin ◽  
Isla Simpson ◽  
Haibo Liu ◽  
Naomi Henderson ◽  
...  
Keyword(s):  
North America ◽  
Great Plains ◽  
Transient Eddy ◽  
Mean Flow ◽  
The West ◽  
The North ◽  
Winter Half ◽  
Summer Half ◽  
The Mean ◽  
The U.S

Abstract The mechanisms of model-projected atmospheric moisture budget change across North America are examined in simulations conducted with 22 models from phase 5 of the Coupled Model Intercomparison Project. Modern-day model budgets are validated against the European Centre for Medium-Range Weather Forecasts Interim Re-Analysis. In the winter half year transient eddies converge moisture across the continent while the mean flow wets the west from central California northward and dries the southwest. In the summer half year there is widespread mean flow moisture divergence across the west and convergence over the Great Plains that is offset by transient eddy divergence. In the winter half year the models project drying for the southwest and wetting to the north. Changes in the mean flow moisture convergence are largely responsible across the west but intensified transient eddy moisture convergence wets the northeast. In the summer half year widespread declines in precipitation minus evaporation (P − E) are supported by mean flow moisture divergence across the west and transient eddy divergence in the Great Plains. The changes in mean flow convergence are related to increases in specific humidity but also depend on changes in the mean flow including increased low-level divergence in the U.S. Southwest and a zonally varying wave that wets the North American west and east coasts in winter and dries the U.S. Southwest. Increased transient eddy fluxes occur even as low-level eddy activity weakens and arise from strengthened humidity gradients. A full explanation of North American hydroclimate changes will require explanation of mean and transient circulation changes and the coupling between the moisture and circulation fields.

Too Close for Comfort: Canada, the U.S. Civil Rights Movement, and the North American Colo(u)r Line

2019 ◽  
Vol 3 (3) ◽  
Author(s):  
Asa McKercher
Keyword(s):  
Civil Rights ◽  
Civil Rights Movement ◽  
North American ◽  
The North ◽  
The U.S

Too Close for Comfort: Canada, the U.S. Civil Rights Movement, and the North American Colo(u)r Line

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