scholarly journals Mechanism of atrazine resistance in atrazine- and HPPD inhibitor-resistant Palmer amaranth (Amaranthus palmeri S. Wats.) from Nebraska

2019 ◽  
Vol 99 (6) ◽  
pp. 815-823 ◽  
Author(s):  
Parminder S. Chahal ◽  
Mithila Jugulam ◽  
Amit J. Jhala
Keyword(s):  
The United States ◽  
Palmer Amaranth ◽  
Target Site ◽  
Cytochrome P450 Monooxygenases ◽  
Amaranthus Palmeri ◽  
Weed Species ◽  
Corn Production ◽  
Agronomic Crops ◽  
P450 Monooxygenases ◽  
Atrazine Resistance

Palmer amaranth (Amaranthus palmeri S. Wats.) is one of the most problematic weed species in agronomic crops in the United States. A Palmer amaranth biotype multiple-resistant to atrazine and 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibitors was reported in a seed corn production field in Nebraska. Rapid detoxification mediated by cytochrome P450 monooxygenases and increased HPPD gene expression were reported as the mechanisms of mesotrione resistance in atrazine- and HPPD inhibitor-resistant Palmer amaranth biotype from Nebraska; however, the mechanism of atrazine resistance is unknown. The objectives of this study were to investigate target site or non-target site based mechanisms conferring atrazine resistance in Palmer amaranth from Nebraska. 14C-atrazine absorption and translocation studies revealed that reduced atrazine absorption or translocation were not involved as one of the mechanisms of atrazine resistance. Instead, greater 14C-atrazine absorption and recovery in treated leaves were observed in resistant compared with susceptible Palmer amaranth. No known mutations including Ser264Gly substitution in the psbA gene causing target site based atrazine resistance were observed. However, the parent 14C-atrazine was metabolized rapidly <4 h after treatment in resistant plants, conferring enhanced atrazine metabolism as the mechanism of resistance.

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.

Target Site–Based and Non–Target Site Based Resistance to ALS Inhibitors in Palmer Amaranth (Amaranthus palmeri)

Weed Science ◽  
2017 ◽  
Vol 65 (6) ◽  
pp. 681-689 ◽  
Author(s):  
Sridevi Nakka ◽  
Curtis R. Thompson ◽  
Dallas E. Peterson ◽  
Mithila Jugulam
Keyword(s):  
Cropping Systems ◽  
Acetolactate Synthase ◽  
The United States ◽  
Palmer Amaranth ◽  
Target Site ◽  
Nucleotide Sequence Analysis ◽  
Response Analysis ◽  
Common Mutation ◽  
Weed Species ◽  
Als Inhibitors

Resistance to acetolactate synthase (ALS)-inhibitor herbicides due to continuous and repeated selection is widespread in many troublesome weed species, including Palmer amaranth, throughout the United States. The objective of this research was to investigate the physiological and molecular basis of resistance to ALS inhibitors in a chlorsulfuron-resistant Palmer amaranth population (KSR). Our results indicate that the KSR population exhibits a high level of resistance to chlorsulfuron compared with two known susceptible populations, MSS and KSS from Mississippi and Kansas, respectively. MSS is highly susceptible to chlorsulfuron, whereas KSS is moderately sensitive. Dose–response analysis revealed that KSR was more than 275-fold more resistant compared with KSS. Nucleotide sequence analysis of theALSgene from the plants that survived chlorsulfuron treatment revealed the possibility of evolution of both target site–based and non–target site based resistance to ALS inhibitors in the KSR population. The most common mutation (Pro-197-Ser) in theALSgene associated with resistance to the sulfonylureas in many weed species was found only in 30% of the KSR population. A preliminary malathion study showed that the remaining 70% of resistant plants might have cytochrome P450–mediated non–target site resistance. This is the first report elucidating the mechanism of resistance to ALS inhibitors in Palmer amaranth from Kansas. Presence of both target site– and non–target site based mechanisms of resistance limits the herbicide options to manage Palmer amaranth in cropping systems.

Palmer Amaranth (Amaranthus palmeri) Control by Glufosinate plus Fluometuron Applied Postemergence to WideStrike®Cotton

2013 ◽  
Vol 27 (2) ◽  
pp. 291-297 ◽  
Author(s):  
Kelly A. Barnett ◽  
A. Stanley Culpepper ◽  
Alan C. York ◽  
Lawrence E. Steckel
Keyword(s):  
United States ◽  
Weed Control ◽  
Acetolactate Synthase ◽  
The United States ◽  
Palmer Amaranth ◽  
Effective Control ◽  
Yield Response ◽  
Amaranthus Palmeri ◽  
Cotton Yield ◽  
Cotton Cultivar

Glyphosate-resistant (GR) weeds, especially GR Palmer amaranth, are very problematic for cotton growers in the Southeast and Midsouth regions of the United States. Glufosinate can control GR Palmer amaranth, and growers are transitioning to glufosinate-based systems. Palmer amaranth must be small for consistently effective control by glufosinate. Because this weed grows rapidly, growers are not always timely with applications. With widespread resistance to acetolactate synthase-inhibiting herbicides, growers have few herbicide options to mix with glufosinate to improve control of larger weeds. In a field study using a WideStrike®cotton cultivar, we evaluated fluometuron at 140 to 1,120 g ai ha−1mixed with the ammonium salt of glufosinate at 485 g ae ha−1for control of GR Palmer amaranth 13 and 26 cm tall. Standard PRE- and POST-directed herbicides were included in the systems. Glufosinate alone injured the WideStrike® cotton less than 10%. Fluometuron increased injury up to 25% but did not adversely affect yield. Glufosinate controlled 13-cm Palmer amaranth at least 90%, and there was no improvement in weed control nor a cotton yield response to fluometuron mixed with glufosinate. Palmer amaranth 26 cm tall was controlled only 59% by glufosinate. Fluometuron mixed with glufosinate increased control of the larger weeds up to 28% and there was a trend for greater yields. However, delaying applications until weeds were 26 cm reduced yield 22% relative to timely application. Our results suggest fluometuron mixed with glufosinate may be of some benefit when attempting to control large Palmer amaranth. However, mixing fluometuron with glufosinate is not a substitute for a timely glufosinate application.

scholarly journals Sex-specific markers for waterhemp (Amaranthus tuberculatus) and Palmer amaranth (Amaranthus palmeri)

Weed Science ◽  
2019 ◽  
Vol 67 (4) ◽  
pp. 412-418 ◽  
Author(s):  
Jacob S. Montgomery ◽  
Ahmed Sadeque ◽  
Darci A. Giacomini ◽  
Patrick J. Brown ◽  
Patrick J. Tranel
Keyword(s):  
Crop Production ◽  
Genetic Basis ◽  
The United States ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Data Set ◽  
Amaranthus Tuberculatus ◽  
Primer Sets ◽  
Male Specific ◽  
Specific Sequences

AbstractWaterhemp [Amaranthus tuberculatus (Moq.) J. D. Sauer] and Palmer amaranth (Amaranthus palmeri S. Watson) are troublesome weeds of row-crop production in the United States. Their dioecious reproductive systems ensure outcrossing, facilitating rapid evolution and distribution of resistances to multiple herbicides. Little is known, however, about the genetic basis of dioecy in Amaranthus species. In this work, we use restriction site–associated DNA sequencing (RAD-Seq) to investigate the genetic basis of sex determination in A. tuberculatus and A. palmeri. For each species, approximately 200 plants of each sex were sampled and used to create RAD-Seq libraries. The resulting libraries were separately bar-coded and then pooled for sequencing with the Illumina platform, yielding millions of 64-bp reads. These reads were analyzed to identify sex-specific and sex-biased sequences. We identified 345 male-specific sequences from the A. palmeri data set and 2,754 male-specific sequences in A. tuberculatus. An unexpected 723 female-specific sequences were identified in a subset of the A. tuberculatus females; subsequent research, however, indicated female specificity of these markers was limited to the population from which they were identified. Primer sets designed to specifically amplify male-specific sequences were tested for accuracy on multiple, geographically distinct populations of A. tuberculatus and A. palmeri, as well as other Amaranthus species. Two primer sets for A. palmeri and four primer sets for A. tuberculatus were each able to distinguish between male and female plants with at least 95% accuracy. In the near term, sex-specific markers will be useful to the A. tuberculatus and A. palmeri research communities (e.g., to predict sex for crossing experiments). In the long-term, this research will provide the foundational tools for detailed investigations into the molecular biology and evolution of dioecy in weedy Amaranthus species.

Management of glyphosate-resistant Palmer amaranth (Amaranthus palmeri) in 2,4-D–, glufosinate-, and glyphosate-resistant soybean

2020 ◽  
pp. 1-8
Author(s):  
Chandrima Shyam ◽  
Parminder S. Chahal ◽  
Amit J. Jhala ◽  
Mithila Jugulam
Keyword(s):  
United States ◽  
Field Experiments ◽  
The United States ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Soybean Yield ◽  
Chlorimuron Ethyl ◽  
Density And Biomass ◽  
Herbicide Programs ◽  
Biomass Reduction

Abstract Glyphosate-resistant (GR) Palmer amaranth is a problematic, annual broadleaf weed in soybean production fields in Nebraska and many other states in the United States. Soybean resistant to 2,4-D, glyphosate, and glufosinate (Enlist E3TM) has been developed and was first grown commercially in 2019. The objectives of this research were to evaluate the effect of herbicide programs applied PRE, PRE followed by (fb) late-POST (LPOST), and early-POST (EPOST) fb LPOST on GR Palmer amaranth control, density, and biomass reduction, soybean injury, and yield. Field experiments were conducted near Carleton, NE, in 2018, and 2019 in a grower’s field infested with GR Palmer amaranth in 2,4-D–, glyphosate-, and glufosinate-resistant soybean. Sulfentrazone + cloransulam-methyl, imazethapyr + saflufenacil + pyroxasulfone, and chlorimuron ethyl + flumioxazin + metribuzin applied PRE provided 84% to 97% control of GR Palmer amaranth compared with the nontreated control 14 d after PRE. Averaged across herbicide programs, PRE fb 2,4-D and/or glufosinate, and sequential application of 2,4-D or glufosinate applied EPOST fb LPOST resulted in 92% and 88% control of GR Palmer amaranth, respectively, compared with 62% control with PRE-only programs 14 d after LPOST. Reductions in Palmer amaranth biomass followed the same trend; however, Palmer amaranth density was reduced 98% in EPOST fb LPOST programs compared with 91% reduction in PRE fb LPOST and 76% reduction in PRE-only programs. PRE fb LPOST and EPOST fb LPOST programs resulted in an average soybean yield of 4,478 and 4,706 kg ha−1, respectively, compared with 3,043 kg ha−1 in PRE-only programs. Herbicide programs evaluated in this study resulted in no soybean injury. The results of this research illustrate that herbicide programs are available for the management of GR Palmer amaranth in 2,4-D–, glyphosate-, and glufosinate-resistant soybean.

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.

Absorption, Translocation, and Metabolism of Glufosinate in Transgenic and Nontransgenic Cotton, Palmer Amaranth (Amaranthus palmeri), and Pitted Morningglory (Ipomoea lacunosa)

Weed Science ◽  
2009 ◽  
Vol 57 (4) ◽  
pp. 357-361 ◽  
Author(s):  
Wesley J. Everman ◽  
Walter E. Thomas ◽  
James D. Burton ◽  
Alan C. York ◽  
John W. Wilcut
Keyword(s):  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Weed Species ◽  
Ipomoea Lacunosa ◽  
Leaf Stage ◽  
Intermediate Metabolism ◽  
Pitted Morningglory ◽  
Cotton Plants ◽  
Treated Leaf ◽  
Harvest Intervals

Greenhouse studies were conducted to evaluate absorption, translocation, and metabolism of14C-glufosinate in glufosinate-resistant cotton, nontransgenic cotton, Palmer amaranth, and pitted morningglory. Cotton plants were treated at the four-leaf stage, whereas Palmer amaranth and pitted morningglory were treated at 7.5 and 10 cm, respectively. All plants were harvested at 1, 6, 24, 48, and 72 h after treatment (HAT). Absorption of14C-glufosinate was greater than 85% 24 h after treatment in Palmer amaranth. Absorption was less than 30% at all harvest intervals for glufosinate-resistant cotton, nontransgenic cotton, and pitted morningglory. At 24 HAT, 49 and 12% of radioactivity was translocated to regions above and below the treated leaf, respectively, in Palmer amaranth. Metabolites of14C-glufosinate were detected in all crop and weed species. Metabolism of14C-glufosinate was 16% or lower in nontransgenic cotton and pitted morningglory; however, metabolism rates were greater than 70% in glufosinate-resistant cotton 72 HAT. Intermediate metabolism was observed for Palmer amaranth, with metabolites comprising 20 to 30% of detectable radioactivity between 6 and 72 HAT.

Evaluating Cover Crops and Herbicides for Glyphosate-Resistant Palmer Amaranth (Amaranthus palmeri) Control in Cotton

2016 ◽  
Vol 30 (2) ◽  
pp. 415-422 ◽  
Author(s):  
Matthew S. Wiggins ◽  
Robert M. Hayes ◽  
Lawrence E. Steckel
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
The United States ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Hairy Vetch ◽  
Cereal Rye ◽  
Crimson Clover ◽  
Legume Cover Crops ◽  
Herbicide Programs

Glyphosate-resistant (GR) weeds, especially GR Palmer amaranth, are very problematic in cotton-producing areas of the midsouthern region of the United States. Growers rely heavily on PRE residual herbicides to control Palmer amaranth since few effective POST options exist. Interest in integrating high-residue cover crops with existing herbicide programs to combat GR weeds has increased. Research was conducted in 2013 and 2014 in Tennessee to evaluate GR Palmer amaranth control when integrating cover crops and PRE residual herbicides. Cereal rye, crimson clover, hairy vetch, winter wheat, and combinations of one grass plus one legume were compared with winter weeds without a cover crop followed by fluometuron or acetochlor applied PRE. Biomass of cover crops was determined prior to termination 3 wk before planting. Combinations of grass and legume cover crops accumulated the most biomass (> 3,500 kg ha−1) but by 28 d after application (DAA) the cereal rye and wheat provided the best Palmer amaranth control. Crimson clover and hairy vetch treatments had the greatest number of Palmer amaranth. These cereal and legume blends reduced Palmer amaranth emergence by half compared to non–cover-treated areas. Fluometuron and acetochlor controlled Palmer amaranth 95 and 89%, respectively, at 14 DAA and 54 and 62%, respectively, at 28 DAA. Cover crops in combination with a PRE herbicide did not adequately control Palmer amaranth.

Differentiation of Life-History Traits among Palmer Amaranth Populations (Amaranthus palmeri) and Its Relation to Cropping Systems and Glyphosate Sensitivity

Weed Science ◽  
2017 ◽  
Vol 65 (3) ◽  
pp. 339-349 ◽  
Author(s):  
Washington Bravo ◽  
Ramon G. Leon ◽  
Jason A. Ferrell ◽  
Michael J. Mulvaney ◽  
C. Wesley Wood
Keyword(s):  
Life History ◽  
Crop Rotation ◽  
Life History Traits ◽  
Cropping Systems ◽  
Glyphosate Resistance ◽  
The United States ◽  
Organic Production ◽  
Palmer Amaranth ◽  
Flowering Plant ◽  
Weed Species

Palmer amaranth’s ability to evolve resistance to different herbicides has been studied extensively, but there is little information about how this weed species might be evolving other life-history traits that could potentially make it more aggressive and difficult to control. We characterized growth and morphological variation among 10 Palmer amaranth populations collected in Florida and Georgia from fields with different cropping histories, ranging from continuous short-statured crops (vegetables and peanut) to tall crops (corn and cotton) and from intensive herbicide use history to organic production. Palmer amaranth populations differed in multiple traits such as fresh and dry weight, days to flowering, plant height, and leaf and canopy shape. Differences between populations for these traits ranged from 36% up to 87%. Although glyphosate-resistant (GR) populations collected from cropping systems including GR crops exhibited higher values of the aforementioned variables than glyphosate-susceptible (GS) populations, variation in traits was not explained by glyphosate resistance or distance between populations. Cropping system components such as crop rotation and crop canopy structure better explained the differences among populations. The higher growth of GR populations compared with GS populations was likely the result of multiple selection forces present in the cropping systems in which they grow rather than a pleiotropic effect of the glyphosate resistance trait. Results suggest that Palmer amaranth can evolve life-history traits increasing its growth and reproduction potential in cropping systems, which explains its rapid spread throughout the United States. Furthermore, our findings highlight the need to consider the evolutionary consequences of crop rotation structure and the use of more competitive crops, which might promote the selection of more aggressive biotypes in weed species with high genetic variability.

Herbicide-Resistant Weeds in the United States and Their Impact on Extension

2009 ◽  
Vol 23 (4) ◽  
pp. 599-603 ◽  
Author(s):  
Barbara A. Scott ◽  
Mark J. Vangessel ◽  
Susan White-Hansen
Keyword(s):  
United States ◽  
Crop Production ◽  
The United States ◽  
Extension Education ◽  
Weed Species ◽  
Common Lambsquarters ◽  
Herbicide Resistant ◽  
Agronomic Crops ◽  
Survey Results ◽  
The Impact

Herbicide-resistant weeds have impacted crop production throughout the United States, but the effect they have on extension programming has not been evaluated. In June 2007, 38 extension weed specialists throughout the United States, responded to a survey on herbicide-resistant (HR) weeds and the impact they are having on extension education programming. Survey results revealed that HR weeds have had a significant impact on extension programming particularly for agronomic crops. In the last 10 yr, agronomic weed specialists' extension programming was almost twice as likely to be impacted by the presence of HR weeds as compared to horticultural programming. In the next 5 yr, agronomic extension programming is twice as likely to be altered. Of 37 weed species reported, seven genera or species of weeds represented 80% of the major HR biotypes reported. These include Amaranthus species, horseweed, Setaria species, common lambsquarters, kochia, giant ragweed, and Lolium species. Five weed species (common ragweed, common lambsquarters, horseweed, kochia, and three foxtail species) exhibited weed by mode of action (MOA) interactions when evaluated as major or minor problems. Herbicide resistance problem severity differed for weed species, herbicide MOA, and crops. The results of this survey of university extension personnel confirm that HR weeds have impacted extension programming and will continue to impact programming in the future.

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