scholarly journals Response of Herbicide-Resistant Palmer Amaranth (Amaranthus palmeri) Accessions to Drought Stress

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Aman Chandi ◽  
David L. Jordan ◽  
Alan C. York ◽  
Jim Burton ◽  
Susana R. Milla-Lewis ◽  
...  
Keyword(s):  
North Carolina ◽  
Drought Stress ◽  
Seedling Emergence ◽  
Acetolactate Synthase ◽  
Dry Weight ◽  
Palmer Amaranth ◽  
Herbicide Resistant ◽  
Synthase Inhibitor ◽  
Limited Moisture ◽  
Moisture Conditions

Palmer amaranth is a very problematic weed in several crops in the southern USA due to its competitive ability and resistance to herbicides representing different mechanisms of action. Variation in growth and subsequent interference of North Carolina Palmer amaranth accessions has not been examined. A greenhouse experiment determined response of 15 North Carolina Palmer amaranth accessions to drought stress beginning 15 days after seedling emergence (DAE) for a duration of 3, 5, 7, and 9 days. Following exposure to drought, plants were grown under optimal moisture conditions until harvest at 30 DAE. Five accessions each of glyphosate-resistant (GR), acetolactate synthase inhibitor-resistant (ALSR), and acetolactate synthase inhibitor-susceptible and glyphosate-susceptible (ALSS/GS) were compared. Variation in response to drought stress, based on height and dry weight reduction relative to nonstressed controls, was noted among accessions. Stress for 3 or more days affected height and dry weight. Height and dry weight of GR and ALSR accession groups were reduced less by drought than the ALSS/GS accession group. Results suggest a possible relationship between herbicide resistance and ability of Palmer amaranth to withstand drought stress and thus a possible competitive advantage for resistant accessions under limited moisture availability.

Palmer Amaranth (Amaranthus palmeri) Management in Dicamba-Resistant Cotton

2015 ◽  
Vol 29 (4) ◽  
pp. 758-770 ◽  
Author(s):  
Charles W. Cahoon ◽  
Alan C. York ◽  
David L. Jordan ◽  
Wesley J. Everman ◽  
Richard W. Seagroves ◽  
...  
Keyword(s):  
United States ◽  
North Carolina ◽  
Field Experiment ◽  
Acetolactate Synthase ◽  
The United States ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Cotton Yield ◽  
Herbicide Resistant

Cotton growers rely heavily upon glufosinate and various residual herbicides applied preplant, PRE, and POST to control Palmer amaranth resistant to glyphosate and acetolactate synthase-inhibiting herbicides. Recently deregulated in the United States, cotton resistant to dicamba, glufosinate, and glyphosate (B2XF cotton) offers a new platform for controlling herbicide-resistant Palmer amaranth. A field experiment was conducted in North Carolina and Georgia to determine B2XF cotton tolerance to dicamba, glufosinate, and glyphosate and to compare Palmer amaranth control by dicamba to a currently used, nondicamba program in both glufosinate- and glyphosate-based systems. Treatments consisted of glyphosate or glufosinate applied early POST (EPOST) and mid-POST (MPOST) in a factorial arrangement of treatments with seven dicamba options (no dicamba, PRE, EPOST, MPOST, PRE followed by [fb] EPOST, PRE fb MPOST, and EPOST fb MPOST) and a nondicamba standard. The nondicamba standard consisted of fomesafen PRE, pyrithiobac EPOST, and acetochlor MPOST. Dicamba caused no injury when applied PRE and only minor, transient injury when applied POST. At time of EPOST application, Palmer amaranth control by dicamba or fomesafen applied PRE, in combination with acetochlor, was similar and 13 to 17% greater than acetochlor alone. Dicamba was generally more effective on Palmer amaranth applied POST rather than PRE, and two applications were usually more effective than one. In glyphosate-based systems, greater Palmer amaranth control and cotton yield were obtained with dicamba applied EPOST, MPOST, or EPOST fb MPOST compared with the standard herbicides in North Carolina. In contrast, dicamba was no more effective than the standard herbicides in the glufosinate-based systems. In Georgia, dicamba was as effective as the standard herbicides in a glyphosate-based system only when dicamba was applied EPOST fb MPOST. In glufosinate-based systems in Georgia, dicamba was as effective as standard herbicides only when dicamba was applied twice.

Susceptibility of Palmer amaranth (Amaranthus palmeri) to herbicides in accessions collected from the North Carolina Coastal Plain

Weed Science ◽  
2020 ◽  
Vol 68 (6) ◽  
pp. 582-593
Author(s):  
Denis J. Mahoney ◽  
David L. Jordan ◽  
Nilda Roma-Burgos ◽  
Katherine M. Jennings ◽  
Ramon G. Leon ◽  
...  
Keyword(s):  
North Carolina ◽  
Dose Response ◽  
Coastal Plain ◽  
Weed Management ◽  
Acetolactate Synthase ◽  
Fold Increase ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Sites Of Action ◽  
Two Populations

AbstractPalmer amaranth (Amaranthus palmeri S. Watson) populations resistant to acetolactate synthase (ALS)-inhibiting herbicides and glyphosate are fairly common throughout the state of North Carolina (NC). This has led farm managers to rely more heavily on herbicides with other sites of action (SOA) for A. palmeri control, especially protoporphyrinogen oxidase and glutamine synthetase inhibitors. In the fall of 2016, seeds from A. palmeri populations were collected from the NC Coastal Plain, the state’s most prominent agricultural region. In separate experiments, plants with 2 to 4 leaves from the 110 populations were treated with field use rates of glyphosate, glufosinate-ammonium, fomesafen, mesotrione, or thifensulfuron-methyl. Percent visible control and survival were evaluated 3 wk after treatment. Survival frequencies were highest following glyphosate (99%) or thifensulfuron-methyl (96%) treatment. Known mutations conferring resistance to ALS inhibitors were found in populations surviving thifensulfuron-methyl application (Ala-122-Ser, Pro-197-Ser, Trp-574-Leu, and/or Ser-653-Asn), in addition to a new mutation (Ala-282-Asp) that requires further investigation. Forty-two populations had survivors after mesotrione application, with one population having 17% survival. Four populations survived fomesafen treatment, while none survived glufosinate. Dose–response studies showed an increase in fomesafen needed to kill 50% of two populations (LD50); however, these rates were far below the field use rate (less than 5 g ha−1). In two populations following mesotrione dose–response studies, a 2.4- to 3.3-fold increase was noted, with LD90 values approaching the field use rate (72.8 and 89.8 g ha−1). Screening of the progeny of individuals surviving mesotrione confirmed the presence of resistance alleles, as there were a higher number of survivors at the 1X rate compared with the parent population, confirming resistance to mesotrione. These data suggest A. palmeri resistant to chemistries other than glyphosate and thifensulfuron-methyl are present in NC, which highlights the need for weed management approaches to mitigate the evolution and spread of herbicide-resistant populations.

Growth Characterization of Kochia (Kochia scoparia) with Substitutions at Pro197or Trp574Conferring Resistance to Acetolactate Synthase–Inhibiting Herbicides

Weed Science ◽  
2013 ◽  
Vol 61 (2) ◽  
pp. 267-276 ◽  
Author(s):  
Anne Légère ◽  
F. Craig Stevenson ◽  
Hugh J. Beckie ◽  
Suzanne I. Warwick ◽  
Eric N. Johnson ◽  
...  
Keyword(s):  
Acetolactate Synthase ◽  
Dry Weight ◽  
Variable Response ◽  
Kochia Scoparia ◽  
Replacement Series ◽  
Mixed Stands ◽  
Population Total ◽  
Factors Affecting ◽  
Herbicide Resistant ◽  
Growth Characterization

Over 90% of Canadian kochia populations are resistant to acetolactate synthase (ALS)– inhibiting herbicides. We questioned whether the target site–based resistance could affect plant growth and competitiveness. Homozygous F2herbicide-resistant (HR) kochia plants with an amino acid substitution at Trp574(sources: Alberta [AB], Saskatchewan [SK], and Manitoba [MB]), or Pro197(MB, AB with two populations) were grown in replacement series with homozygous F2herbicide-susceptible (HS) plants from the corresponding heterogeneous population (total: six populations). In pure stands, growth of HR plants from AB and SK was similar to that of HS plants, regardless of mutation; conversely, MB2-HR plants (Trp574Leu) developed more slowly and were taller than MB2-HS plants. Final dry weight of HR plants in pure stands was similar across all six populations, whereas that for HS plants in pure stands and HR–HS plants in mixed stands (50–50%) varied with population. Results for AB and SK populations suggest little impact of either ALS mutation on kochia growth, whereas those for MB lines would suggest an unidentified factor (or factors) affecting the HS, HR, or both biotypes. The variable response within and between lines, and across HS biotypes highlights the importance of including populations of various origins and multiple susceptible controls in HR biotype studies.

scholarly journals Interference of Selected Palmer Amaranth (Amaranthus palmeri) Biotypes in Soybean (Glycine max)

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Aman Chandi ◽  
David L. Jordan ◽  
Alan C. York ◽  
Susana R. Milla-Lewis ◽  
James D. Burton ◽  
...  
Keyword(s):  
Glycine Max ◽  
Acetolactate Synthase ◽  
Dry Weight ◽  
Glyphosate Resistance ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Fresh Weight ◽  
Row Crops ◽  
Soybean Yield ◽  
Competitive Disadvantage

Palmer amaranth (Amaranthus palmeriS. Wats.) has become difficult to control in row crops due to selection for biotypes that are no longer controlled by acetolactate synthase inhibiting herbicides and/or glyphosate. Early season interference in soybean [Glycine max(L.) Merr.] for 40 days after emergence by three glyphosate-resistant (GR) and three glyphosate-susceptible (GS) Palmer amaranth biotypes from Georgia and North Carolina was compared in the greenhouse. A field experiment over 2 years compared season-long interference of these biotypes in soybean. The six Palmer amaranth biotypes reduced soybean height similarly in the greenhouse but did not affect soybean height in the field. Reduction in soybean fresh weight and dry weight in the greenhouse; and soybean yield in the field varied by Palmer amaranth biotypes. Soybean yield was reduced 21% by Palmer amaranth at the established field density of 0.37 plant m−2. When Palmer amaranth biotypes were grouped by response to glyphosate, the GS group reduced fresh weight, dry weight, and yield of soybean more than the GR group. The results indicate a possible small competitive disadvantage associated with glyphosate resistance, but observed differences among biotypes might also be associated with characteristics within and among biotypes other than glyphosate resistance.

Environmental Impact of Glyphosate-Resistant Weeds in Canada

Weed Science ◽  
2014 ◽  
Vol 62 (2) ◽  
pp. 385-392 ◽  
Author(s):  
Hugh J. Beckie ◽  
Peter H. Sikkema ◽  
Nader Soltani ◽  
Robert E. Blackshaw ◽  
Eric N. Johnson
Keyword(s):  
Environmental Impact ◽  
Weed Control ◽  
Acetolactate Synthase ◽  
Application Rate ◽  
Weed Species ◽  
Common Ragweed ◽  
Herbicide Resistant ◽  
Herbicide Treatments ◽  
Relative Potential ◽  
Synthase Inhibitor

Glyphosate-resistant (GR) giant ragweed, horseweed, and common ragweed were confirmed in southwestern Ontario, Canada in 2008, 2010, and 2011, respectively. In the western prairie provinces of Alberta and Saskatchewan, GR (plus acetolactate synthase inhibitor-resistant) kochia was discovered in 2011. This symposium paper estimates the environmental impact (EI) of the top herbicide treatments or programs used to manage these GR weed species in the major field crops grown in each region. For each herbicide treatment, EI (per ha basis) was calculated as the environmental impact quotient (EIQ), which quantifies the relative potential risk of pesticide active ingredients on human and ecological health based on risk components to farm workers, consumers, and the environment, multiplied by the application rate (kg ai ha−1). Total EI is defined as EI (per ha basis) multiplied by the application area (i.e., land area affected by a GR weed). It was assumed that all herbicide treatments would supplement the continued usage of glyphosate because of its broad spectrum weed control. For the control of these GR weeds, most treatments contain auxinic or protoporphyrinogen oxidase (PPO)-inhibiting herbicides. The majority of auxinic herbicide treatments result in low (EI ≤ 10) to moderate (11 to 20) EI, whereas all treatments of PPO inhibitors have low EI. Total EI of GR horseweed and kochia will generally be greater than that of giant or common ragweed because of rapid seed dispersal. For recommended herbicide treatments to control GR weeds (and herbicide-resistant weeds in general), EI data should be routinely included with cost and site of action in weed control extension publications and software, so that growers have the information needed to assess the EI of their actions.

Survival of annual ryegrass (Lolium rigidum Gaud.) in a Mediterranean type environment. 1. Effect of summer grazing by sheep on seed numbers and seed germination in autumn

1977 ◽  
Vol 28 (1) ◽  
pp. 81 ◽  
Author(s):  
D Gramshaw ◽  
WR Stern
Keyword(s):  
Germination Rate ◽  
Seedling Emergence ◽  
Subterranean Clover ◽  
Soil Surface ◽  
Dry Weight ◽  
Annual Ryegrass ◽  
Grazing History ◽  
Total Dry Weight ◽  
Moisture Conditions ◽  
Summer Grazing

Annual ryegrass–subterranean clover pastures that produced about 5000 kg total dry weight per hectare and 23,500 ryegrass seed per sq metre in spring were grazed by sheep at different stocking rates during summer. Intensive stocking equivalent to about 3000 sheep days ha-1 reduced seed numbers by 20%. Under continuous grazing, about 70% of the seed produced in spring fell readily to the ground during summer. The remaining seed was firmly held in seed heads, and apparently sheep ate mainly this component. Less than 1% of the seed ingested was voided in the faeces. No significant changes in seed numbers over summer were observed in ungrazed pasture. Subsequently, at the break of season in autumn, germination of seeds was examined in situ near the soil surface. The summer grazing history of pastures influenced the percentage of seeds that germinated; more seeds germinated in heavily than in leniently grazed pastures. Whether the pasture was leniently or heavily grazed, there was little effect on germination of shed seeds. Seeds in seed heads were found to germinate more slowly than seeds shed to the soil surface. Seedling emergence in autumn was regulated mainly by the interrelationship between the germination rate of the seed population, depending on summer-early autumn rains, and the period for which favourable moisture conditions prevailed at the soil surface after rain began in autumn. In the field, temperature and light appeared to be unimportant in influencing germination at the break of season. Dynamics of seed and seedling numbers in annual ryegrass pastures in a Mediterranean type environment, particularly at the break of season, are discussed.

Confirmation and Control of Triazine and 4-Hydroxyphenylpyruvate Dioxygenase-Inhibiting Herbicide-Resistant Palmer Amaranth (Amaranthus palmeri) in Nebraska

2014 ◽  
Vol 28 (1) ◽  
pp. 28-38 ◽  
Author(s):  
Amit J. Jhala ◽  
Lowell D. Sandell ◽  
Neha Rana ◽  
Greg R. Kruger ◽  
Stevan Z. Knezevic
Keyword(s):  
Acetolactate Synthase ◽  
The United States ◽  
Oxidase Inhibitor ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Corn Production ◽  
Herbicide Resistant ◽  
South Central ◽  
Fold Level ◽  
And Control

Palmer amaranth is a difficult-to-control broadleaf weed that infests corn and soybean fields in south-central and southwestern Nebraska and several other states in the United States. The objectives of this research were to confirm triazine and 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide-resistant Palmer amaranth in Nebraska and to determine sensitivity and efficacy of POST-applied corn herbicides for control of resistant and susceptible Palmer amaranth biotypes. Seeds from a putative HPPD-resistant Palmer amaranth biotype from Fillmore County, NE were collected from a seed corn production field in fall 2010. The response of Palmer amaranth biotypes to 12 rates (0 to 12×) of mesotrione, tembotrione, topramezone, and atrazine was evaluated in a dose–response bioassay in a greenhouse. On the basis of the values at the 90% effective dose (ED90) level, the analysis showed a 4- to 23-fold resistance depending upon the type of HPPD-inhibiting herbicide being investigated and susceptible biotype used for comparison. This biotype also had a 9- to 14-fold level of resistance to atrazine applied POST. Results of a POST-applied herbicide efficacy study suggested a synergistic interaction between atrazine and HPPD-inhibiting herbicides that resulted in > 90% control of all Palmer amaranth biotypes. The resistant biotype had a reduced sensitivity to acetolactate synthase inhibiting herbicides (halosulfuron and primisulfuron), a photosystem-II inhibitor (bromoxynil), and a protoporphyrinogen oxidase inhibitor (fluthiacet-methyl). Palmer amaranth biotypes were effectively controlled (≥ 90%) with glyphosate, glufosinate, and dicamba, whereas 2,4-D ester provided 81 to 83% control of the resistant biotype and > 90% control of both susceptible biotypes.

Acetolactate Synthase–Inhibitor Resistance in Yellow Nutsedge (Cyperus esculentus): II—Physiognomy and Photoperiodic Response

Weed Science ◽  
2015 ◽  
Vol 63 (4) ◽  
pp. 819-827 ◽  
Author(s):  
Parsa Tehranchian ◽  
Jason K. Norsworthy ◽  
Muthukumar V. Bagavathiannan ◽  
Dilpreet S. Riar
Keyword(s):  
Intergenic Spacer ◽  
Acetolactate Synthase ◽  
Photoperiodic Response ◽  
Purple Nutsedge ◽  
Herbicide Resistant ◽  
Yellow Nutsedge ◽  
Tuber Production ◽  
Synthase Inhibitor ◽  
Inhibitor Resistance

Yellow nutsedge is one of the most problematic weedy sedges in rice–soybean systems of the Mississippi Delta region. An acetolactate synthase (ALS)-inhibiting, herbicide-resistant (Res) yellow nutsedge biotype was recently documented in eastern Arkansas, which showed intermediary growth habit between yellow nutsedge and purple nutsedge and also exhibited differential photoperiodic sensitivity to flowering. The objectives of this study were to: (a) determine variation in reproductive characteristics of theResbiotype and three susceptible (Sus) yellow nutsedge biotypes, (b) understand the influence of photoperiod on growth and reproduction, (c) understand the potential role of seeds in population establishment, and (d) elucidate the phylogenetic relationships between theResyellow nutsedge biotype and purple nutsedge. Tuber production per plant and tuber weight of theResbiotype were less than that of theSusbiotypes. Differences in quantitative traits, such as shoot and tuber production existed between theResandSusbiotypes for photoperiods ranging from 12 to 16 h. Generally, photoperiods greater than 12 h increased shoot development in all yellow nutsedge biotypes, with differential responses among the biotypes. Number of tubers reached the maximum for theResbiotype at a 14-h photoperiod. Over a 90-d period, inflorescence formation was only observed in theResbiotype with maximum flowering and seed production in the 14-h photoperiod. Subsequent tests revealed up to 18% seed germination, suggesting that seed could also play a role (in addition to tubers) in the persistence and spread of theResyellow nutsedge. Phylogenetic analysis based on ribosomal DNA internal transcribed spacer (ITS) regions and mitochondrialnad4gene intergenic spacer sequences indicated that theResbiotype was more closely associated withSusyellow nutsedge biotypes. Nevertheless, 100% similarity for thenad4gene sequences between theResyellow nutsedge biotype and a reference purple nutsedge suggests that theResbiotype is likely a result of hybridization between yellow and purple nutsedges, which perhaps explains the intermediary growth characteristics observed in theResbiotype.

Confirmation of Shattercane (Sorghum bicolor) Resistance to ALS-Inhibiting Herbicides in Ohio

2002 ◽  
Vol 3 (1) ◽  
pp. 2
Author(s):  
Traci L. Brenly-Bultemeier ◽  
Jeff Stachler ◽  
S. Kent Harrison
Keyword(s):  
Sorghum Bicolor ◽  
Soil Seed Bank ◽  
Resistance Mechanism ◽  
Acetolactate Synthase ◽  
Dry Weight ◽  
Cross Resistance ◽  
Herbicide Resistant ◽  
Shoot Dry Weight ◽  
Als Inhibitors ◽  
Sorghum Bicolor L

A population of shattercane (Sorghum bicolor (L.) Moench) located in Fairfield County, Ohio, was investigated for herbicide resistance after it persisted in a field that had been treated repeatedly with herbicides that inhibit acetolactate synthase (ALS). Herbicide bioassays confirmed cross-resistance of the suspected resistant (R) population to the ALS inhibitors nicosulfuron, primisulfuron, and imazethapyr. Herbicide doses required to reduce R shattercane shoot dry weight 50% (i.e., the GR50 values) were > 35,000, > 40,000, and 34,215 g ai/ha for nicosulfuron, primisulfuron, and imazethapyr, respectively. In contrast, GR50 values for the same herbicides applied to a susceptible (S) shattercane population from an adjacent county were 0.185, 0.025, and 0.038 g/ha, respectively. The high levels of resistance exhibited by the R population suggest that the resistance mechanism is due to one or more alterations in ALS, the herbicide target site. Effective management of ALS herbicide-resistant shattercane will require an integrated strategy designed to isolate the R population and deplete its soil seed bank while minimizing herbicide selection pressure. Accepted for publication 14 October 2002. Published 21 October 2002.

Control and Cross-Resistance of an Acetolactate Synthase Inhibitor-Resistant Palmer Amaranth (Amaranthus palmeri) Biotype

1997 ◽  
Vol 11 (1) ◽  
pp. 132-137 ◽  
Author(s):  
Jason W. Gaeddert ◽  
Dallas E. Peterson ◽  
Michael J. Horak
Keyword(s):  
Rate Control ◽  
Cultural Practices ◽  
Acetolactate Synthase ◽  
Mechanisms Of Action ◽  
Palmer Amaranth ◽  
Cross Resistance ◽  
Amaranthus Palmeri ◽  
Partial Control ◽  
Synthase Inhibitor ◽  
Control Tank

Over two years, acetolactate synthase (ALS)-inhibiting herbicides and herbicides with different mechanisms of action were tested individually and in combination for control of ALS-resistant Palmer amaranth in soybean. As expected, ALS-inhibiting herbicides did not control the resistant Palmer amaranth. Lactofen at 210 g/ha and acifluorfen at 560 g/ha gave the best postemergence control. Tank mixes of lactofen with either imazethapyr or chlorimuron plus thifensulfuron did not significantly increase control over lactofen alone. Sequential treatment with a soil-applied herbicide, either SAN 582 or pendimethalin, followed by lactofen postemergence, controlled weeds best (greater than 85%). The extent of cross-resistance of Palmer amaranth to ALS-inhibiting herbicides was determined in the greenhouse. Sixteen POST ALS-inhibiting herbicides were sprayed at ½, 1, 2, 4, and 8X field use rates on resistant and susceptible biotypes. All ALS-inhibiting herbicides at all rates controlled the susceptible biotype. The resistant biotype was cross-resistant to all ALS-inhibiting herbicides. Metsulfuron and imazapyr at 8X rates were the only treatments that provided 80% or greater control of the ALS-resistant Palmer amaranth. Chlorsulfuron and tribenuron were the only other herbicides that gave partial control at the highest rate. Control with these four herbicides decreased as the rate was decreased. Experimental results suggest that cultural practices and herbicides with different mechanisms of action will be required to manage this ALS-resistant Palmer amaranth biotype.

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