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Resistance To Glyphosate In Palmer Amaranth Amaranthus Palmeri Populations From New Mexico Pecan Orchards
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Book Synopsis Resistance to Glyphosate in Palmer Amaranth (Amaranthus Palmeri) Populations from New Mexico Pecan Orchards by : Mohsen Mohseni Moghadam
Download or read book Resistance to Glyphosate in Palmer Amaranth (Amaranthus Palmeri) Populations from New Mexico Pecan Orchards written by Mohsen Mohseni Moghadam and published by . This book was released on 2013 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Assessing the Genetic Diversity in Palmer Amaranth (Amaranthus Palmeri) Populations from New Mexico and Arizona by : Hormat Shadgou
Download or read book Assessing the Genetic Diversity in Palmer Amaranth (Amaranthus Palmeri) Populations from New Mexico and Arizona written by Hormat Shadgou and published by . This book was released on 2016 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gene flow has been suggested as one of the main reasons for the geographic expansion of Palmer amaranth. Information on the genetic diversity of the populations would help the understanding of the possible role for gene flow in geographic expansion of Palmer amaranth in New Mexico. Furthermore, information on the genetic diversity would be helpful in determining the origin of reported glyphosate-resistant Palmer amaranth populations in New Mexico. Hence, the objectives of this study were to identify the interspecific genetic diversity among 22 Palmer amaranth populations from New Mexico and Arizona and to compare the interspecific genetic diversity of two glyphosate-resistant and two glyphosate-susceptible populations from adjacent locations in Southern New Mexico. The SSR marker analysis of Palmer amaranth populations in this study showed high genetic diversity among individual Palmer amaranth plants, however, this analysis did not cluster the populations based on their geographic locations. The lack of clustering based on the geographic locations can be an indication of extensive gene flow between the locations. Moreover, the results from the intraspecific genetic diversity study indicated that the glyphosate-resistant and –susceptible populations from Southern New Mexico had similar genetic background. The SSR marker analysis did not cluster the individuals from any of the populations together, therefore, based on these results it is likely that resistance to glyphosate in the two Palmer amaranth populations in this study has been the result of local selection pressure from glyphosate in Southern New Mexico. These results also suggest that gene flow is one of the major factors in spread of glyphosate-resistant Palmer amaranth populations, highlighting the importance of prevention in weed management strategies.
Book Synopsis Evaluation of San Joaquin Valley Palmer Amaranth (Amaranthus Palmeri) Populations for Glyphosate Resistance and Tolerance by : Sonia Inez Rios
Download or read book Evaluation of San Joaquin Valley Palmer Amaranth (Amaranthus Palmeri) Populations for Glyphosate Resistance and Tolerance written by Sonia Inez Rios and published by . This book was released on 2014 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Response of Glyphosate Resistant Palmer Amaranth (Amaranthus Palmeri) to Protoporphyrinogen Oxidase Inhibiting Herbicides in Tennessee by : Alinna Marie Umphres
Download or read book Response of Glyphosate Resistant Palmer Amaranth (Amaranthus Palmeri) to Protoporphyrinogen Oxidase Inhibiting Herbicides in Tennessee written by Alinna Marie Umphres and published by . This book was released on 2017 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: In many agronomic cropping systems across the United States, Palmer amaranth (Amaranthus palmeri) is the most economic and troublesome weed for producers. The introduction of glyphosate resistant (GR) crops gave producers the benefit of controlling Palmer amaranth as well as other weeds, a broad window of application, and reduced tillage practices. With the confirmation of GR Palmer amaranth, producers implemented protoporphyrinogen oxidase (PPO or Protox)-inhibiting herbicides to control these populations in crops such as soybean [Glycine max (L.) Merr.] and cotton [Gossypium hirsutum (L.)]. However the continuous use of PPO herbicides has caused a shift in Palmer amaranth populations for PPO resistance. Therefore the scope of this study was to observe fomesafen response to four Palmer amaranth populations, determine the fomesafen resistance level, evaluate the effect of Palmer amaranth size on fomesafen efficacy, determine susceptibility to other foliar-applied herbicides, and evaluate the efficacy of four soil-applied PPO-inhibiting herbicides on PPO-resistant (PPO-R) and PPOsusceptible (PPO-S) Palmer amaranth populations. The PPO-S population was observed with 98% control however, fomesafen efficacy was reduced in SPA, LPA, and WPA populations with 24%, 4%, and 2% control, respectively at 14 days after treatment (DAT). The level of resistance for the PPO-R population SPA was 4-fold relative to the PPO-S population KPA. When determining the height of Palmer amaranth on fomesafen efficacy, control of SPA Sm, Md, and Lg sized plants was 62%, 49%, and 18%, respectively. Atrazine, glufosinate, and mesotrione were observed to have the greatest control (>70%) of the SPA population but resistant to glyphosate and chlorimuron. When subjected to soil-applied PPO herbicides, SPA showed reduced control with fomesafen and saflufenacil however greater control was observed with flumioxazin and sulfentrazone at 35 DAT.
Book Synopsis Herbicide-Resistant Palmer Amaranth (Amaranthus Palmeri S. Wats.) in the United States - Mechanisms of Resistance, Impact, and Management by : Parminder S. Chahal
Download or read book Herbicide-Resistant Palmer Amaranth (Amaranthus Palmeri S. Wats.) in the United States - Mechanisms of Resistance, Impact, and Management written by Parminder S. Chahal and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Palmer amaranth, a dioecious summer annual species, is one of the most troublesome weeds in the agronomic crop production systems in the United States. In the last two decades, continuous reliance on herbicide(s) with the same mode of action as the sole weed management strategy has resulted in the evolution of herbicide-resistant (HR) weeds, including Palmer amaranth. By 2015, Palmer amaranth biotypes had been confirmed resistant to acetolactate synthase (ALS)-inhibitors, dinitroanilines, glyphosate, hydroxyphenylpyruvate dioxygenase (HPPD)-inhibitors, and triazine herbicides in some parts of the United States along with multiple HR biotypes. Mechanisms of herbicide-resistance in Palmer amaranth are discussed in this chapter. Preplant herbicide options including glufosinate, 2,4-D, and dicamba provide excellent Palmer amaranth control; however, their application is limited before planting crops, which is often not possible due to unfavorable weather conditions. Agricultural biotechnology companies are developing new multiple HR crops that will allow the post-emergence application of respective herbicides for management of HR weeds, including Palmer amaranth. For the effective in-crop management of Palmer amaranth, and to reduce the potential for the evolution of other HR weeds, growers should apply herbicides with different modes of action in tank-mixture and should also incorporate cultural practices including inversion tillage and cover crops along with herbicide programs.
Book Synopsis Characterization of Glyphosate-resistant Amaranthus Palmeri (Palmer Amaranth) Tolerance to ALS- and HPPD-inhibiting Herbicides by : Shilpa Singh
Download or read book Characterization of Glyphosate-resistant Amaranthus Palmeri (Palmer Amaranth) Tolerance to ALS- and HPPD-inhibiting Herbicides written by Shilpa Singh and published by . This book was released on 2017 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: Palmer amaranth is a principal weed problem across the United States and is resistant to several herbicide modes of action. By 2008, Palmer amaranth in Arkansas was reported to be resistant to both ALS- and EPSPS-inhibitors, but the predominant resistance mechanisms are yet to be explored. Herbicide options with different modes of action are needed to provide effective Palmer amaranth control and HPPD-inhibitors (e.g. mesotrione) are among these. The goal of this research was to elucidate the resistance profile of Palmer amaranth in Arkansas to ALS herbicides and glyphosate (EPSPS-inhibitor) as well as evaluate the differential tolerance of Palmer amaranth to mesotrione. This research aimed to (1) evaluate the response of Palmer amaranth populations to the full dose of glyphosate and mesotrione; (2) determine if tolerance to mesotrione is heritable; (3) determine the mechanism of resistance to glyphosate in selected accessions; and (4) verify the target-site as the mechanism of resistance in ALS-resistant Palmer amaranth. For objective 1, a total of 119 accessions were collected from crop fields in Arkansas between 2008 and 2014. Overall, 55% of the accessions (115) were glyphosate-resistant (GR). Mesotrione controlled 74% of the accessions (119); the remaining accessions had survivors with high injury (61%-90%). For objective 2, low level of tolerance to mesotrione (3- to 5-fold) was observed in four recalcitrant accessions. For objective 3, 20 accessions were selected. GR accessions had ED50 494 g ha-1 to 1355 g ha-1 and for susceptible accessions ED50 ranged from 28 g ha-1 to 207 g ha-1. EPSPS gene amplification was the primary mechanism of resistance. For objective 4, Palmer amaranth accessions were cross-resistant to pyrithiobac and trifloxysulfuron. Out of 20 accessions, 19 showed 21- to 56-fold resistance to trifloxysulfuron than the susceptible. Four and seven increased ALS copies were observed in a single plant from White and Mississippi counties, respectively, indicating the elevated ALS copies as potential mechanism of resistance in these accessions. Although, all accessions but susceptible had Trp574Ser mutation along with Ala122Thr, Pro197Ala and Ser653Asn present in a few plants, confirming mutations at the target-site as the main mechanism of resistance to ALS-inhibitors.
Book Synopsis Physiological, and Genetic Characterization of 2,4-D-resistant Palmer Amaranth (Amaranthus Palmeri S. Watson) and Its Management by : Chandrima Shyam
Download or read book Physiological, and Genetic Characterization of 2,4-D-resistant Palmer Amaranth (Amaranthus Palmeri S. Watson) and Its Management written by Chandrima Shyam and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Palmer amaranth (Amaranthus palmeri S. Watson) is one of the topmost troublesome, C4 dioecious weeds in the US. Biological traits such as aggressive growth habits, prolific seed production, and the ability to withstand environmental stresses hinder control of this weed. Additionally, numerous Palmer amaranth populations across the US have been found to have evolved resistance to multiple herbicides. In 2018, a population of Palmer amaranth from a conservation tillage study from Riley County, Kansas was suspected to have evolved resistance to multiple herbicides including 2,4-dichlorophenoxyacetic acid (2,4-D) and was designated as Kansas Conservation Tillage Resistant (KCTR). 2,4-D, a synthetic auxin herbicide, is widely used for controlling broadleaf weeds in cereal crops. However, over-reliance on 2,4-D to control other herbicide-resistant weeds, along with the commercialization of 2,4-D-tolerant crop technology, has resulted in increased usage of this herbicide. The objectives of this dissertation were to 1) characterize the evolution of multiple herbicide resistance including 2,4-D in KCTR Palmer amaranth; 2) investigate the physiological mechanism of 2,4-D resistance in KCTR compared to two known susceptible Palmer amaranth populations i.e., Kansas Susceptible (KSS) and Mississippi Susceptible (MSS); 3) assess the genetic basis of 2,4-D resistance in KCTR; and 4) evaluate herbicide programs that can manage glyphosate-resistant Palmer amaranth in 2,4-D tolerant soybean. Experiments were conducted under either greenhouse or controlled growth chamber conditions. Standard herbicide dose-response, physiological, biochemical (using radiolabeled herbicides), breeding, and field experiments were designed and conducted. The results of these experiments found that KCTR Palmer amaranth had evolved resistance to six herbicide modes of action, including acetolactate synthase (ALS)-, photosystem II (PS II)-, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS)-, 4-hydroxyphenylpyruvate dioxygenase (HPPD)-, protoporphyrinogen oxidase (PPO)- inhibitors, and synthetic auxins (2,4-D). Sequencing and analyses of genes coding for the herbicide targets indicated absence of all known mutations that confer resistance, except for EPSPS-inhibitor, with a massive amplification of EPSPS gene (up to 88 copies). Investigation of non-target site resistance mechanism(s) in KCTR confirmed the predominance of metabolic resistance to multiple herbicides mediated by either cytochrome P450 (P450) or glutathione S-transferase enzyme activity. Whole-plant dose-response analyses confirmed a 6- to 11- fold resistance to 2,4-D in KCTR compared to two susceptible populations (KSS or MSS). [14C] 2,4-D uptake and translocation studies indicated a 10% less and 3 times slower translocation of [14C] 2,4-D in KCTR compared to susceptible populations, while there was no difference in the amount of [14C] 2,4-D absorbed. However, KCTR plants metabolized [14C] 2,4-D much faster than the susceptible KSS and MSS, suggesting that enhanced metabolism bestows resistance to this herbicide in KCTR. Further, use of P450-inhibitor (e.g., malathion) indicated that the metabolism of 2,4-D in KCTR is mediated by P450 activity. Genetic analyses of F1 and F2 progenies, derived from crossing between KCTR and KSS, revealed that 2,4-D resistance in KCTR Palmer amaranth is an incompletely dominant, nuclear trait. Segregation of F2 progenies did not follow the Mendelian single gene inheritance model (3:1), suggesting the involvement of multiple genes in mediating 2,4-D resistance in KCTR. Evaluation of herbicide programs for Palmer amaranth management in the field suggested that pre-emergence herbicides with residual activity followed by post-emergence application of either 2,4-D or glufosinate or 2,4-D and glufosinate can control glyphosate-resistant Palmer amaranth in 2,4-D-tolerant soybean. Overall, the outcome of this dissertation documents the first case of a six-way resistance in a single Palmer amaranth population and also for the first time characterizes the physiological and genetic basis of 2,4-D resistance in this weed. These findings will help in predicting and minimizing further evolution and spread of 2,4-D resistance in Palmer amaranth.
Book Synopsis Glyphosate-resistant Palmer Amaranth (amaranthus Palmeri) in Arkansas by : Griff Michael Griffith
Download or read book Glyphosate-resistant Palmer Amaranth (amaranthus Palmeri) in Arkansas written by Griff Michael Griffith and published by . This book was released on 2013 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since 2000, there have been thirteen weed species confirmed resistant (R) to glyphosate in the United States, six of those resistant species are present in Arkansas. The goal of this research was to confirm and to determine the level of resistance in two R Palmer amaranth biotypes from Mississippi (MC-R) and Lincoln (LC-R) Counties, Arkansas, and one susceptible (S) biotype from Clarendon County, South Carolina, which had never been exposed to glyphosate. Shikimic acid concentration over time was significantly greater in the S biotype than both the MC-R and LC-R biotypes. The lethal dose required to kill 50% (LD50) of the population was 2,255 and 3,223 g ae ha -1 for the MC-R and LC-R biotypes, respectively, and it was hypothesized that the two Arkansas biotypes each had a different resistance mechanism. Results indicate metabolism of glyphosate to its major metabolite, aminomethylphosphonic acid (AMPA), was not responsible for resistance in any biotype. Reduced absorption in the LC-R and limited translocation from the treated leaf in the MC-R were at least partially responsible for the observed resistance to glyphosate. The LC-R biotype effectively colonized a field within two years of a single resistant female producing ̃20,000 seed. Cotton lint yield was reduced over 100 kg ha-1 by some densities of LC-R Palmer, depending on the soil and relative elevation in that region. Several resistant management options exist in cotton; however, results indicate that timely herbicide applications based off of Palmer amaranth size are required for effective season-long control and management of the soil seedbank.
Book Synopsis Evaluation of a Cultural Practice and 2,4-D-based Herbicide Programs for Glyphosate-resistant Palmer Amaranth Management by : Benjamin Haynes Lawrence
Download or read book Evaluation of a Cultural Practice and 2,4-D-based Herbicide Programs for Glyphosate-resistant Palmer Amaranth Management written by Benjamin Haynes Lawrence and published by . This book was released on 2015 with total page 73 pages. Available in PDF, EPUB and Kindle. Book excerpt: Glyphosate-resistant Palmer amaranth (Amaranthus palmeri [S.] Wats) is an economically troublesome weed to southeastern United States soybean (Glycine max [L.] Merr.) growers. Palmer amaranth is troublesome due to its evolution of resistance to multiple herbicide modes of action, competiveness, and prolific seed production. Greenhouse studies were conducted at the Delta Research and Extension Center in Stoneville, MS to evaluate different rates of 2,4- dichlorophenoxyacetic acid (2,4-D) for control of Palmer amaranth. Field experiments were conducted at the Delta Research and Extension Center in Stoneville, MS in 2013 and 2014 to evaluate Palmer amaranth emergence using a cultural practice and a residual herbicide. Field experiments were also conducted at the Delta Research and Extension Center in Stoneville, MS in 2013 and 2014 to evaluate Palmer amaranth control with applications of glyphosate, glufosinate, and 2,4-D alone and in mixtures.
Book Synopsis Resistance Screening and Control Options for Glyphosate-resistant Palmer Amaranth (amaranthus Palmeri) in Cotton (gossypium Hirsutum) by : Ryan Christopher Doherty
Download or read book Resistance Screening and Control Options for Glyphosate-resistant Palmer Amaranth (amaranthus Palmeri) in Cotton (gossypium Hirsutum) written by Ryan Christopher Doherty and published by . This book was released on 2012 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the mid-2000's, glyphosate-resistant Palmer amaranth biotypes began to emerge in many southern states. In 2006, glyphosate-resistant Palmer amaranth was identified in a field in Mississippi County, Arkansas. A greenhouse experiment was conducted in 2008 to screen Palmer amaranth accessions, collected in this survey, for glyphosate resistance. Inflorescence were collected from a total of 276 plants from fields were glyphosate failure occurred, representing 74 accessions in 14 counties, including Clay, Craighead, Crittenden, Greene, Jackson, Jefferson, Lawrence, Lee, Mississippi, Phillips, Poinsett, Randolph, St. Francis, and White Counties. Eight of the 74 accessions did not produce viable seed. In the greenhouse, 32 of the 66 Palmer amaranth accessions screened were at least 10% glyphosate-resistant. Two counties (Lee and St. Francis) contained Palmer amaranth accessions that were greater than 80% glyphosate-resistant. Every accession tested had at least one survivor following glyphosate at 0.86 kg ae/ha. Three field experiments were conducted in 2006 and 2007 to determine if preplant-applied fomesafen and postemergence-applied glufosinate would provide control of Palmer amaranth without causing cotton injury. A total of, 28 preplant (PPL) and preemergence (PRE) herbicide treatments and 27 herbicide programs were evaluated for Palmer amaranth control. The 28 PPL and PRE treatments were also evaluated for cotton injury. The 28 PPL and PRE treatments were fomesafen, flumioxazin, fluometuron, prometryn, diuron, and pendimethalin applied at four preplant timings (21, 14, 7, and 0 days). The Liberty Link herbicide programs, utilized glufosinate, S-metolachlor, fomesafen, fluometuron, prometryn, flumioxazin, diuron, and pendimethalin to control Palmer amaranth. At 7 days after emergence (DAE) of cotton, fomesafen applied at 0.21 and 0.28 kg ai/ha, flumioxazin at 0.071 kg ai/ha, prometryn at 1.12 kg ai/ha, diuron at 0.56 kg ai/ha, and pendimethalin at 1.12 kg ai/ha applied at 21, 14, 7, and 0 DPP all controlled Palmer amaranth 90 to 100%. Fomesafen at 0.21 kg ai/ha and flumioxazin at 0.071 kg ai/ha applied at 0 days prior to planting (DPP) reduced stand by 22 and 58%, respectively, when compared to those same treatments applied 21 DPP. Application timing was the only significant factor to affect cotton yield in the PPL and PRE study.
Book Synopsis Mechanisms and Variability of Glyphosate Resistance in Amaranthus Palmeri and Ipomoea Lacunosa by :
Download or read book Mechanisms and Variability of Glyphosate Resistance in Amaranthus Palmeri and Ipomoea Lacunosa written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The resistance of Palmer amaranth (PA) and the tolerance (natural resistance) of pitted morningglory (PM) to glyphosate have made these species among the most common and troublesome weeds in the southeastern U.S. since the adoption of glyphosate-resistant (GR) crops. Populations of GR PA (R1 and R2) were identified in Mississippi. The inheritance of glyphosate resistance was examined in reciprocal crosses (RC) between glyphosate-resistant (R) and -susceptible (S) parents (Female-S × Male-R, S/R, and Female-R × Male-S, R/S), and second reciprocal crosses (2RC) (Female-S/R × Male-S/R, S/R//S/R, and Female-R/S × Male-R/S, R/S//R/S). Dose-response assays resulted in 17- to 4-fold resistance to glyphosate compared with S. Population S accumulated 325- and 8-times more shikimate at the highest glyphosate dose than in R1 and R2, respectively. cDNA sequence analysis of the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene indicated no target site mutation. Genomes of R1, R2, RC, and 2RC contained from 1- to 59-fold more copies of EPSPS gene than S; EPSPS was highly expressed in R1 and R/S, but was poorly expressed in S, S/R, and R2. EPSPS activity was lower in S and S/R than in R and R/S, glyphosate absent; all were inhibited by glyphosate. Western Blot analysis confirmed an increased EPSPS protein level to EPSPS copy number correlation. Thus, the level of resistance was decidedly influenced by the direction of the cross. R and S female plants were reproductively isolated and seed were still produced, suggesting that PA can produce seed both apomictically and sexually (facultative apomixis). This mode of reproduction determined the low copy number inheritance, as well as guaranteeing the GR trait stability in the R populations. Dose-response assays resulted in 2.6-fold variability in tolerance to glyphosate between the most tolerant (MT) and the least tolerant (LT) PM populations. The level of tolerance positively correlated with the time of exposure to GR-crop system. Less shikimate was recovered in MT as compared to LT. Levels of aminomethylphosphonic acid (AMPA) were not different between populations and sarcosine was not present in either populations. Consequently, metabolism of glyphosate to AMPA or sarcosine is not a common factor in explaining natural resistance levels.
Book Synopsis Molecular Genetics of Glyphosate Resistance in Palmer Amaranth (Amaranthus Palmeri L.) by : Todd A. Gaines
Download or read book Molecular Genetics of Glyphosate Resistance in Palmer Amaranth (Amaranthus Palmeri L.) written by Todd A. Gaines and published by . This book was released on 2009 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Characterization and Management of PPO and Glyphosate Resistant Palmer Amaranth by : Drake Copeland
Download or read book Characterization and Management of PPO and Glyphosate Resistant Palmer Amaranth written by Drake Copeland and published by . This book was released on 2018 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research was conducted from the fall of 2016 to the fall of 2018 to characterize and manage PPO- and glyphosate-resistant Palmer amaranth (Amaranthus palmeri S. Wats). Studies included a multi-county survey to determine the prevalence of PPO-resistant Palmer amaranth biotypes and the PPX2 mutations that confer PPO resistance, an in-field evaluation of control of PPO-resistant and PPO-susceptible Palmer amaranth populations with herbicide treatments applied at either sunrise or midday, and field studies that evaluated cover crop termination for control of Palmer amaranth in Roundup Ready Xtend® and Liberty Link® soybean systems [(Glycine max (L.) Merr.]. Results from this research indicate that PPO-resistant Palmer amaranth infests roughly 80% of west Tennessee fields, at least two herbicides with different, effective sites of action should be applied timely for POST herbicidal control of PPO-resistant Palmer amaranth, and that delaying cover crop termination in both Roundup Ready Xtend® and Liberty Link® soybeans can effectively reduce in-season POST applications and maximize Palmer amaranth control if the correct residual herbicide is included at planting timing.
Book Synopsis Postemergence and Residual Control of Glyphosate-resistant Palmer Amaranth (Amaranthus Palmeri) with Dicamba by : Clifford Blake Edwards
Download or read book Postemergence and Residual Control of Glyphosate-resistant Palmer Amaranth (Amaranthus Palmeri) with Dicamba written by Clifford Blake Edwards and published by . This book was released on 2013 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: On-farm research was conducted in 2011 and 2012 to determine the postemergence and residual control by dicamba of glyphosate-resistant (GR) Palmer amaranth (Amaranthus palmeri S. Wats.). Preemergence dicamba at 0, 0.28, 0.56, and 1.1 kg ae ha−1 and 0.07 kg ae ha−1 flumioxazin was applied at 30, 15 and 0 days prior to planting. Postemergence dicamba at 0.28, 0.56, and 1.1 kg ae ha−1 with and without 0.84 kg ae ha−1 glyphosate was applied to 5, 10 and 15 cm Palmer amaranth. In addition, a greenhouse experiment was conducted in 2012 to evaluate and confirm the optimum rate for control of Palmer amaranth with a new formulation of dicamba (BAS 18322H). In the greenhouse, dicamba at 0.14, 0.28, 0.56, 1.1, and 2.2 kg ae ha−1 was applied to 5, 10, and 15 cm Palmer amaranth.
Book Synopsis Integrating New Technology and Strategies for Management of Glyphosate-resistant Palmer Amaranth (Amaranthus Palmeri) in Cotton (Gossypium Hirsutum) by : Charles William Cahoon (Jr.)
Download or read book Integrating New Technology and Strategies for Management of Glyphosate-resistant Palmer Amaranth (Amaranthus Palmeri) in Cotton (Gossypium Hirsutum) written by Charles William Cahoon (Jr.) and published by . This book was released on 2015 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Resistance to Herbicides Conferred by Amaranthus Palmeri Protoporphyrinogen IX Oxidase Mutations by : Pamela Carvalho de Lima
Download or read book Resistance to Herbicides Conferred by Amaranthus Palmeri Protoporphyrinogen IX Oxidase Mutations written by Pamela Carvalho de Lima and published by . This book was released on 2020 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Palmer amaranth (Amaranthus palmeri S. Wats.) is one of the most problematic agronomic weeds to control in fields across Arkansas. Thus far, this species has evolved resistance to several herbicides, including protoporphyrinogen IX oxidase (PPO) inhibitors. The majority of PPO-resistant Palmer amaranth populations harbor a target-site mutation (substitution or deletion of amino acids). The objective of this thesis was to identify the level of fomesafen resistance conferred by PPO2 mutations from Palmer amaranth. The experiments conducted aimed to (1) characterize the level of resistance conferred by the transgene Palmer amaranth ppo2 carrying EG210 mutation into the wild type rice (Oryza sativa cv. 'Nipponbare'); and (2) study the resistance level of Palmer amaranth plants having a single mutation (EG210 or G399A) or a combination. For objective 1, 'Nipponbare' rice was transformed with Palmer amaranth ppo2 EG210 gene via particle bombardment. The presence of the transgene in T0 plants was confirmed, and seeds (T1) were harvested. After selection with foliar treatment of fomesafen (0.78 kg ai ha-1), T1 plants carrying the mutation and showing low injury were maintained to produce T2 seeds. Soil-based assay was conducted with T2 seeds and the survivors were cultured to produce T3 seeds. Seeds from each surviving plant were kept as a separate line. The insertion of Palmer amaranth ppo2 EG210 conferred resistance to fomesafen in rice. The data suggests that only homozygous transgenic plants had full resistance to fomesafen. For objective 2, one susceptible and six resistant accessions were used to conduct dose response assay with the PPO-herbicide, fomesafen, and to test cross resistance or multiple resistance. Selected survivors from these tests were genotyped for the two expected mutations. Homozygosity of EG210 was correlated with high fomesafen resistance. At higher fomesafen rates, survivors carrying EG210 in both alleles or accumulating EG210+G399A recovered better than heterozygous EG210 plants. Populations with higher frequency of individuals with these mutation profiles were also less sensitive to the other two PPO-herbicides tested, saflufenacil and trifludimoxazin.
Book Synopsis Palmer Amaranth (Amaranthus Palmeri) Control in Double-crop Dicamba/glyphosate Resistant Soybean (Glycine Max) and Dicamba and 2,4-D Efficacy on Palmer Amaranth and Common Waterhemp (Amaranthus Rudis) by : Nathaniel Russell Thompson
Download or read book Palmer Amaranth (Amaranthus Palmeri) Control in Double-crop Dicamba/glyphosate Resistant Soybean (Glycine Max) and Dicamba and 2,4-D Efficacy on Palmer Amaranth and Common Waterhemp (Amaranthus Rudis) written by Nathaniel Russell Thompson and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Auxin herbicides have been widely used for broadleaf weed control since the mid-1940's. With new auxinic herbicide-resistant traits in corn, soybean, and cotton, use of these herbicides is likely to increase. Glyphosate-resistant Palmer amaranth (Amaranthus palmeri) and common waterhemp (Amaranthus rudis) are two primary problematic weed species that will be targeted with dicamba and 2,4-D in the new systems. No-till double-crop soybean after winter wheat harvest is a popular cropping system in central and eastern Kansas, however, management of glyphosate resistant Palmer amaranth has become a serious issue. Field experiments were established near Manhattan and Hutchinson, KS, in 2016 and 2017, to compare seventeen herbicide treatments for control of Palmer amaranth and large crabgrass (Digitaria sanguinalis) in dicamba/glyphosate resistant no-till double-crop soybean after winter wheat. Herbicide programs that included a residual preemergence (PRE) treatment followed by a postemergence (POST) treatment offered greater Palmer amaranth control 8 weeks after planting when compared to PRE-only, POST-only and burndown-only treatments. All treatments that contained glyphosate POST provided complete control of large crabgrass compared to less than 43% control with PRE-only treatments. Soybean grain yield was greater in programs that included PRE followed by POST treatments, compared to PRE-only and burndown-only treatments. A second set of field experiments were established in 2017 near Manhattan and Ottawa, KS to evaluate dicamba and 2,4-D POST efficacy on Palmer amaranth and common waterhemp. Five rates of dicamba (140, 280, 560, 1121, and 2242 g ae ha−1) and 2,4-D (140, 280, 560, 1121, and 2242 g ae ha−1) were used to evaluate control of the Amaranthus spp. Each experiment was conducted twice at each location. Dicamba provided better Palmer amaranth and common waterhemp control than 2,4-D across the rates evaluated. Control of Palmer amaranth was 94% and 99% with dicamba rates of 1121 and 2242 g ae ha−1, respectively, but 2,4-D never provided more than 80% control at any rate. The highest rates of both dicamba and 2,4-D provided greater than 91% common waterhemp control, but control was less than 78% with all other rates of both herbicides. Palmer amaranth and common waterhemp control did not exceed 73% with the highest labelled POST rates of either dicamba or 2,4-D. Auxinic herbicide-resistant traits in corn, soybean, and cotton offer new options for controlling glyphosate-resistant Palmer amaranth and common waterhemp, however proper stewardship is vital to maintain their effectiveness.
