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Bryan G. Young - One of the best experts on this subject based on the ideXlab platform.
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An Improved Method to Shorten Physiological Dormancy of Giant Ragweed ( Ambrosia Trifida ) Seed
Weed Science, 2019Co-Authors: Nick T. Harre, Stephen C. Weller, Bryan G. YoungAbstract:Timely results from whole-plant, herbicide-resistant weed screenings are crucial to heighten grower awareness. However, the high degree of physiological dormancy of giant ragweed ( Ambrosia Trifida L.) seed exacerbates this process. The most effective methods for alleviating dormancy, to date, are either labor-intensive (embryo excision) or require several weeks (soil stratification). This research describes a conditioning process involving clipping and aeration of seed in water that is highly effective at alleviating dormancy and requires less skill and time compared with previous techniques. Ambrosia Trifida seeds were collected over 2 yr at two different collection timings (September 25, “early”; October 25, “late”), subjected to various treatments intended to release dormancy, and evaluated for emergence over 18 d in the greenhouse. The use of germination-promoting chemicals (ethephon, gibberellic acid, and thiourea) generally provided no increase in emergence compared with water and occasionally produced seedlings with abnormal growth unsuitable for further experimentation. Conditioning yielded between 30% and 33% emergence for both early and late collections of seeds with no afterripening period compared with 0% emergence for seeds imbibed in water. Following an 8-wk period of dry storage at 4 C, conditioning yielded nearly 80% emergence for both collection timings, while emergence of seeds imbibed in water was 10% and 27% for early and late collections, respectively. Soil stratification in moist soil for 8 wk at 4 C was the second most effective treatment, yielding 46% to 49% emergence across both collections. Parameters of the Weibull function further indicated the conditioning treatment had the fastest rate of emergence and shortest lag phase between planting and first emergence. Methods to germinate A. Trifida without an afterripening period have previously been unsuccessful. Therefore, the seed-conditioning method outlined in this work will be useful in expediting the confirmation of herbicide-resistant A. Trifida incidences.
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differential antioxidant enzyme activity in rapid response glyphosate resistant Ambrosia Trifida
Pest Management Science, 2018Co-Authors: Nick T. Harre, Haozhen Nie, Yiwei Jiang, Bryan G. YoungAbstract:BACKGROUND The giant ragweed (Ambrosia Trifida L.) rapid-response (RR) biotype exhibits a sacrificial form of glyphosate resistance whereby an oxidative burst in mature leaves results in foliage loss, while juvenile leaves remain uninjured. This work investigated the safening capacity of antioxidant enzymes in RR juvenile leaves following glyphosate treatment and examined cross tolerance to paraquat. RESULTS Basal antioxidant enzyme activities were similar between glyphosate-susceptible (GS) and RR biotypes. Lipid peroxidation was first detected in RR mature leaves at 8 h after treatment (HAT) and by 32 HAT was 5.3 and 21.1 times greater than that in RR juvenile leaves and GS leaves, respectively. Preceding lipid peroxidation in the RR biotype at 2 and 4 HAT, the only increase in enzymatic activity was observed in ascorbate-glutathione cycle enzymes in RR juvenile leaves, particularly ascorbate peroxidase, dehydroascorbate reductase, and glutathione reductase. Sensitivity to paraquat was similar between biotypes. CONCLUSION The RR biotype is not inherently more tolerant to oxidative stress. The difference in tissue damage between RR juvenile and mature leaves following glyphosate treatment is attributable at least partially to the transient increase in antioxidant enzyme expression in juvenile leaves (0-8 HAT), but may also be attributable to lower overall RR induction in juvenile leaves compared with mature leaves. © 2018 Society of Chemical Industry.
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Differential antioxidant enzyme activity in rapid‐response glyphosate‐resistant Ambrosia Trifida
Pest management science, 2018Co-Authors: Nick T. Harre, Haozhen Nie, Yiwei Jiang, Bryan G. YoungAbstract:BACKGROUND The giant ragweed (Ambrosia Trifida L.) rapid-response (RR) biotype exhibits a sacrificial form of glyphosate resistance whereby an oxidative burst in mature leaves results in foliage loss, while juvenile leaves remain uninjured. This work investigated the safening capacity of antioxidant enzymes in RR juvenile leaves following glyphosate treatment and examined cross tolerance to paraquat. RESULTS Basal antioxidant enzyme activities were similar between glyphosate-susceptible (GS) and RR biotypes. Lipid peroxidation was first detected in RR mature leaves at 8 h after treatment (HAT) and by 32 HAT was 5.3 and 21.1 times greater than that in RR juvenile leaves and GS leaves, respectively. Preceding lipid peroxidation in the RR biotype at 2 and 4 HAT, the only increase in enzymatic activity was observed in ascorbate-glutathione cycle enzymes in RR juvenile leaves, particularly ascorbate peroxidase, dehydroascorbate reductase, and glutathione reductase. Sensitivity to paraquat was similar between biotypes. CONCLUSION The RR biotype is not inherently more tolerant to oxidative stress. The difference in tissue damage between RR juvenile and mature leaves following glyphosate treatment is attributable at least partially to the transient increase in antioxidant enzyme expression in juvenile leaves (0-8 HAT), but may also be attributable to lower overall RR induction in juvenile leaves compared with mature leaves. © 2018 Society of Chemical Industry.
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Environmental Factors Moderate Glyphosateinduced Antagonism of POST Herbicides on the Rapid Response Biotype of Glyphosate-Resistant Giant Ragweed (Ambrosia Trifida)
Weed Science, 2018Co-Authors: Nick T. Harre, Julie M. Young, Bryan G. YoungAbstract:Abstract In the rapid response (RR) biotype of glyphosate-resistant (GR) giant ragweed (Ambrosia Trifida L.), exposure to glyphosate elicits H2O2 production in mature leaves, resulting in foliage loss and reduced glyphosate translocation. When glyphosate is applied with POST herbicides intended to improve control of A. Trifida, the RR to glyphosate has the propensity to antagonize these herbicide combinations. This research documents how transient changes in air temperature, soil moisture, and light intensity during a 6-d period surrounding herbicide application regulate induction of the RR and the effect on POST herbicide interactions with glyphosate. Air temperature had the greatest influence on H2O2 accumulation in leaf disks following treatment with glyphosate, as plants at 30 C produced more than twice the amount of H2O2 at 2.5 h after treatment compared with 10 C. Plants under field capacity conditions accumulated nearly 50% more H2O2 than those at one-third field capacity, while those under no shad...
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Glyphosate-Induced Antagonism in Rapid Response Giant Ragweed (Ambrosia Trifida)
Weed Technology, 2017Co-Authors: Nick T. Harre, Julie M. Young, Bryan G. YoungAbstract:Glyphosate application to the rapid-response (RR) biotype of glyphosate-resistant (GR) giant ragweed ensues in loss of foliage via rapid tissue death, thereby reducing glyphosate translocation. Experiments were performed to determine if this GR response, in contrast to a non-rapid response (NRR) GR biotype, results in antagonism of the selective herbicides atrazine, cloransulam, dicamba, lactofen, and topramezone. Application of glyphosate at 1,680 g ae ha-1 in the greenhouse resulted in antagonism between all five selective herbicides for the RR biotype, whereas glyphosate applied at 420 g ha-1 was antagonistic only for cloransulam. Application of selective herbicides 2 d prior to glyphosate treatment avoided the antagonism observed in the RR biotype. In the field, glyphosate mixtures with dicamba and topramezone were antagonistic on the RR biotype across both 2015 and 2016 field seasons. Thus, the RR effectively reduces glyphosate efficacy but also has potential to diminish the activity of glyphosate mixtures with selective herbicides, and the degree of antagonism between these mixtures escalates at increasing glyphosate rates.Nomenclature: Atrazine; cloransulam; dicamba; glyphosate; lactofen; topramezone; giant ragweed, Ambrosia Trifida L. AMBTR
Nick T. Harre - One of the best experts on this subject based on the ideXlab platform.
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An Improved Method to Shorten Physiological Dormancy of Giant Ragweed ( Ambrosia Trifida ) Seed
Weed Science, 2019Co-Authors: Nick T. Harre, Stephen C. Weller, Bryan G. YoungAbstract:Timely results from whole-plant, herbicide-resistant weed screenings are crucial to heighten grower awareness. However, the high degree of physiological dormancy of giant ragweed ( Ambrosia Trifida L.) seed exacerbates this process. The most effective methods for alleviating dormancy, to date, are either labor-intensive (embryo excision) or require several weeks (soil stratification). This research describes a conditioning process involving clipping and aeration of seed in water that is highly effective at alleviating dormancy and requires less skill and time compared with previous techniques. Ambrosia Trifida seeds were collected over 2 yr at two different collection timings (September 25, “early”; October 25, “late”), subjected to various treatments intended to release dormancy, and evaluated for emergence over 18 d in the greenhouse. The use of germination-promoting chemicals (ethephon, gibberellic acid, and thiourea) generally provided no increase in emergence compared with water and occasionally produced seedlings with abnormal growth unsuitable for further experimentation. Conditioning yielded between 30% and 33% emergence for both early and late collections of seeds with no afterripening period compared with 0% emergence for seeds imbibed in water. Following an 8-wk period of dry storage at 4 C, conditioning yielded nearly 80% emergence for both collection timings, while emergence of seeds imbibed in water was 10% and 27% for early and late collections, respectively. Soil stratification in moist soil for 8 wk at 4 C was the second most effective treatment, yielding 46% to 49% emergence across both collections. Parameters of the Weibull function further indicated the conditioning treatment had the fastest rate of emergence and shortest lag phase between planting and first emergence. Methods to germinate A. Trifida without an afterripening period have previously been unsuccessful. Therefore, the seed-conditioning method outlined in this work will be useful in expediting the confirmation of herbicide-resistant A. Trifida incidences.
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differential antioxidant enzyme activity in rapid response glyphosate resistant Ambrosia Trifida
Pest Management Science, 2018Co-Authors: Nick T. Harre, Haozhen Nie, Yiwei Jiang, Bryan G. YoungAbstract:BACKGROUND The giant ragweed (Ambrosia Trifida L.) rapid-response (RR) biotype exhibits a sacrificial form of glyphosate resistance whereby an oxidative burst in mature leaves results in foliage loss, while juvenile leaves remain uninjured. This work investigated the safening capacity of antioxidant enzymes in RR juvenile leaves following glyphosate treatment and examined cross tolerance to paraquat. RESULTS Basal antioxidant enzyme activities were similar between glyphosate-susceptible (GS) and RR biotypes. Lipid peroxidation was first detected in RR mature leaves at 8 h after treatment (HAT) and by 32 HAT was 5.3 and 21.1 times greater than that in RR juvenile leaves and GS leaves, respectively. Preceding lipid peroxidation in the RR biotype at 2 and 4 HAT, the only increase in enzymatic activity was observed in ascorbate-glutathione cycle enzymes in RR juvenile leaves, particularly ascorbate peroxidase, dehydroascorbate reductase, and glutathione reductase. Sensitivity to paraquat was similar between biotypes. CONCLUSION The RR biotype is not inherently more tolerant to oxidative stress. The difference in tissue damage between RR juvenile and mature leaves following glyphosate treatment is attributable at least partially to the transient increase in antioxidant enzyme expression in juvenile leaves (0-8 HAT), but may also be attributable to lower overall RR induction in juvenile leaves compared with mature leaves. © 2018 Society of Chemical Industry.
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Differential antioxidant enzyme activity in rapid‐response glyphosate‐resistant Ambrosia Trifida
Pest management science, 2018Co-Authors: Nick T. Harre, Haozhen Nie, Yiwei Jiang, Bryan G. YoungAbstract:BACKGROUND The giant ragweed (Ambrosia Trifida L.) rapid-response (RR) biotype exhibits a sacrificial form of glyphosate resistance whereby an oxidative burst in mature leaves results in foliage loss, while juvenile leaves remain uninjured. This work investigated the safening capacity of antioxidant enzymes in RR juvenile leaves following glyphosate treatment and examined cross tolerance to paraquat. RESULTS Basal antioxidant enzyme activities were similar between glyphosate-susceptible (GS) and RR biotypes. Lipid peroxidation was first detected in RR mature leaves at 8 h after treatment (HAT) and by 32 HAT was 5.3 and 21.1 times greater than that in RR juvenile leaves and GS leaves, respectively. Preceding lipid peroxidation in the RR biotype at 2 and 4 HAT, the only increase in enzymatic activity was observed in ascorbate-glutathione cycle enzymes in RR juvenile leaves, particularly ascorbate peroxidase, dehydroascorbate reductase, and glutathione reductase. Sensitivity to paraquat was similar between biotypes. CONCLUSION The RR biotype is not inherently more tolerant to oxidative stress. The difference in tissue damage between RR juvenile and mature leaves following glyphosate treatment is attributable at least partially to the transient increase in antioxidant enzyme expression in juvenile leaves (0-8 HAT), but may also be attributable to lower overall RR induction in juvenile leaves compared with mature leaves. © 2018 Society of Chemical Industry.
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Environmental Factors Moderate Glyphosateinduced Antagonism of POST Herbicides on the Rapid Response Biotype of Glyphosate-Resistant Giant Ragweed (Ambrosia Trifida)
Weed Science, 2018Co-Authors: Nick T. Harre, Julie M. Young, Bryan G. YoungAbstract:Abstract In the rapid response (RR) biotype of glyphosate-resistant (GR) giant ragweed (Ambrosia Trifida L.), exposure to glyphosate elicits H2O2 production in mature leaves, resulting in foliage loss and reduced glyphosate translocation. When glyphosate is applied with POST herbicides intended to improve control of A. Trifida, the RR to glyphosate has the propensity to antagonize these herbicide combinations. This research documents how transient changes in air temperature, soil moisture, and light intensity during a 6-d period surrounding herbicide application regulate induction of the RR and the effect on POST herbicide interactions with glyphosate. Air temperature had the greatest influence on H2O2 accumulation in leaf disks following treatment with glyphosate, as plants at 30 C produced more than twice the amount of H2O2 at 2.5 h after treatment compared with 10 C. Plants under field capacity conditions accumulated nearly 50% more H2O2 than those at one-third field capacity, while those under no shad...
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Glyphosate-Induced Antagonism in Rapid Response Giant Ragweed (Ambrosia Trifida)
Weed Technology, 2017Co-Authors: Nick T. Harre, Julie M. Young, Bryan G. YoungAbstract:Glyphosate application to the rapid-response (RR) biotype of glyphosate-resistant (GR) giant ragweed ensues in loss of foliage via rapid tissue death, thereby reducing glyphosate translocation. Experiments were performed to determine if this GR response, in contrast to a non-rapid response (NRR) GR biotype, results in antagonism of the selective herbicides atrazine, cloransulam, dicamba, lactofen, and topramezone. Application of glyphosate at 1,680 g ae ha-1 in the greenhouse resulted in antagonism between all five selective herbicides for the RR biotype, whereas glyphosate applied at 420 g ha-1 was antagonistic only for cloransulam. Application of selective herbicides 2 d prior to glyphosate treatment avoided the antagonism observed in the RR biotype. In the field, glyphosate mixtures with dicamba and topramezone were antagonistic on the RR biotype across both 2015 and 2016 field seasons. Thus, the RR effectively reduces glyphosate efficacy but also has potential to diminish the activity of glyphosate mixtures with selective herbicides, and the degree of antagonism between these mixtures escalates at increasing glyphosate rates.Nomenclature: Atrazine; cloransulam; dicamba; glyphosate; lactofen; topramezone; giant ragweed, Ambrosia Trifida L. AMBTR
Péter Poczai - One of the best experts on this subject based on the ideXlab platform.
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Development of chloroplast microsatellite markers for giant ragweed (Ambrosia Trifida).
Applications in plant sciences, 2020Co-Authors: Himanshu Sharma, Jaakko Hyvönen, Péter PoczaiAbstract:Premise Plant invasions are increasing globally, and extensive study of the genetic background of the source and invading populations is needed to understand such biological processes. For this reason, chloroplast microsatellite markers were identified to explore the genetic diversity of the noxious weed Ambrosia Trifida (Asteraceae). Methods and Results The complete chloroplast genome of A. Trifida was mined for microsatellite loci, and 15 novel chloroplast primers were identified to assess the genetic diversity of 49 Ambrosia samples. The number of alleles amplified ranged from two to six, with an average of 3.2 alleles per locus. Shannon's information index varied from 0.305 and 1.467, expected heterozygosity ranged from 0.178 to 0.645, and the polymorphism information content value ranged from 0.211 to 0.675 (average 0.428). The cross-species transferability of the 15 microsatellite loci was also evaluated in four related Ambrosia species (A. artemisiifolia, A. maritima, A. psilostachya, and A. tenuifolia). Conclusions The novel chloroplast microsatellite markers developed in the current study demonstrate substantial cross-species transferability and will be helpful in future genetic diversity studies of A. Trifida and related species.
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Sequencing the Plastid Genome of Giant Ragweed (Ambrosia Trifida, Asteraceae) From a Herbarium Specimen.
Frontiers in plant science, 2019Co-Authors: Gaurav Sablok, Jaakko Hyvönen, Ali Amiryousefi, Péter PoczaiAbstract:We report the first plastome sequence of giant ragweed (Ambrosia Trifida); with this new genome information, we assessed phylogeny of Asteraceae and the transcriptional profiling against glyphosate resistance in giant ragweed. Assembly and genic features show a normal angiosperm quadripartite plastome structure with no signatures of deviation in gene directionality. Comparative analysis revealed large inversions across the plastome of giant ragweed and the previously sequenced members of the plant family. Asteraceae plastid genomes contain two inversions of 22.8-kb and 3.3-kb, with the former located between trnS-GCU and trnG-UCC genes, while the other is between trnE-UUC and trnT-GGU genes. The plastid genome sequences of A. Trifida and the related species, A. artemisiifolia, are identical in gene content and arrangement, but they differ in length. The phylogeny obtained is well resolved and congruent with previous hypotheses about phylogenetic relationship of Asteraceae. The origin of Ambrosia is dated to ca. 16 My BP (13 - 20 My BP). Expression divergence revealed differences in the relative expressions at the exonic and intronic levels providing hints towards the ecological adaptation of the genus. Giant ragweed shows various levels of glyphosate resistance with introns displaying higher expression patterns in resistant time points after the assumed herbicide treatment.
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Image_3_Sequencing the Plastid Genome of Giant Ragweed (Ambrosia Trifida, Asteraceae) From a Herbarium Specimen.pdf
2019Co-Authors: Gaurav Sablok, Jaakko Hyvönen, Ali Amiryousefi, Péter PoczaiAbstract:We report the first plastome sequence of giant ragweed (Ambrosia Trifida); with this new genome information, we assessed the phylogeny of Asteraceae and the transcriptional profiling against glyphosate resistance in giant ragweed. Assembly and genic features show a normal angiosperm quadripartite plastome structure with no signatures of deviation in gene directionality. Comparative analysis revealed large inversions across the plastome of giant ragweed and the previously sequenced members of the plant family. Asteraceae plastid genomes contain two inversions of 22.8 and 3.3 kb; the former is located between trnS-GCU and trnG-UCC genes, and the latter between trnE-UUC and trnT-GGU genes. The plastid genome sequences of A. Trifida and the related species, Ambrosia artemisiifolia, are identical in gene content and arrangement, but they differ in length. The phylogeny is well-resolved and congruent with previous hypotheses about the phylogenetic relationship of Asteraceae. Transcriptomic analysis revealed divergence in the relative expressions at the exonic and intronic levels, providing hints toward the ecological adaptation of the genus. Giant ragweed shows various levels of glyphosate resistance, with introns displaying higher expression patterns at resistant time points after the assumed herbicide treatment.
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Table_4_Sequencing the Plastid Genome of Giant Ragweed (Ambrosia Trifida, Asteraceae) From a Herbarium Specimen.docx
2019Co-Authors: Gaurav Sablok, Jaakko Hyvönen, Ali Amiryousefi, Péter PoczaiAbstract:We report the first plastome sequence of giant ragweed (Ambrosia Trifida); with this new genome information, we assessed the phylogeny of Asteraceae and the transcriptional profiling against glyphosate resistance in giant ragweed. Assembly and genic features show a normal angiosperm quadripartite plastome structure with no signatures of deviation in gene directionality. Comparative analysis revealed large inversions across the plastome of giant ragweed and the previously sequenced members of the plant family. Asteraceae plastid genomes contain two inversions of 22.8 and 3.3 kb; the former is located between trnS-GCU and trnG-UCC genes, and the latter between trnE-UUC and trnT-GGU genes. The plastid genome sequences of A. Trifida and the related species, Ambrosia artemisiifolia, are identical in gene content and arrangement, but they differ in length. The phylogeny is well-resolved and congruent with previous hypotheses about the phylogenetic relationship of Asteraceae. Transcriptomic analysis revealed divergence in the relative expressions at the exonic and intronic levels, providing hints toward the ecological adaptation of the genus. Giant ragweed shows various levels of glyphosate resistance, with introns displaying higher expression patterns at resistant time points after the assumed herbicide treatment.
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Image_1_Sequencing the Plastid Genome of Giant Ragweed (Ambrosia Trifida, Asteraceae) From a Herbarium Specimen.tiff
2019Co-Authors: Gaurav Sablok, Jaakko Hyvönen, Ali Amiryousefi, Péter PoczaiAbstract:We report the first plastome sequence of giant ragweed (Ambrosia Trifida); with this new genome information, we assessed the phylogeny of Asteraceae and the transcriptional profiling against glyphosate resistance in giant ragweed. Assembly and genic features show a normal angiosperm quadripartite plastome structure with no signatures of deviation in gene directionality. Comparative analysis revealed large inversions across the plastome of giant ragweed and the previously sequenced members of the plant family. Asteraceae plastid genomes contain two inversions of 22.8 and 3.3 kb; the former is located between trnS-GCU and trnG-UCC genes, and the latter between trnE-UUC and trnT-GGU genes. The plastid genome sequences of A. Trifida and the related species, Ambrosia artemisiifolia, are identical in gene content and arrangement, but they differ in length. The phylogeny is well-resolved and congruent with previous hypotheses about the phylogenetic relationship of Asteraceae. Transcriptomic analysis revealed divergence in the relative expressions at the exonic and intronic levels, providing hints toward the ecological adaptation of the genus. Giant ragweed shows various levels of glyphosate resistance, with introns displaying higher expression patterns at resistant time points after the assumed herbicide treatment.
Emilie E. Regnier - One of the best experts on this subject based on the ideXlab platform.
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A mosaic of phenotypic variation in giant ragweed (Ambrosia Trifida): Local- and continental-scale patterns in a range-expanding agricultural weed.
Evolutionary applications, 2018Co-Authors: Stephen M. Hovick, S. Kent Harrison, Andrea Mcardle, Emilie E. RegnierAbstract:Spatial patterns of trait variation across a species' range have implications for population success and evolutionary change potential, particularly in range-expanding and weedy species that encounter distinct selective pressures at large and small spatial scales simultaneously. We investigated intraspecific trait variation in a common garden experiment with giant ragweed (Ambrosia Trifida), a highly variable agricultural weed with an expanding geographic range and broad ecological amplitude. Our study included paired populations from agricultural and natural riparian habitats in each of seven regions ranging east to west from the core of the species' distribution in central Ohio to southeastern Minnesota, which is nearer the current invasion front. We observed trait variation across both large- and small-scale putative selective gradients. At large scales, giant ragweed populations from the westernmost locations were nearly four times more fecund and had a nearly 50% increase in reproductive allocation compared to populations from the core. The degree of surface texture on fruits also declined from east to west. Greater fecundity in the west represents a putative trade-off between fruit size and fruit number across the study region, although no such trade-off was found across individual plants. This pattern may effectively result in greater propagule pressure closer to the invasion front. At smaller spatial scales, plants from agricultural populations emerged later and were smaller than plants from riparian populations. However, because plants from agricultural populations allocated more biomass to reproduction, total fecundity did not differ across habitats. Our emergence data are consistent with previous observations showing delayed emergence in agricultural compared to natural populations; thus evolutionary change may be predictable as giant ragweed continues spreading into agricultural fields throughout North America. These shifts in life-history strategy apparently bear no fecundity cost, suggesting that giant ragweed's success can be attributed at least in part to its substantial adaptive potential.
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Bibliometric Analysis of the Literature on Giant Ragweed (Ambrosia Trifida L.)
Journal of Agricultural & Food Information, 2013Co-Authors: Florian Diekmann, Robert A. Ford, S. Kent Harrison, Emilie E. Regnier, Ramaro VenkateshAbstract:Giant ragweed (Ambrosia Trifida L.) has become one of the most persistent and problematic weeds to farmers and allergy sufferers in North America over the last decades. This study aims to identify and assess the scholarly literature using a bibliometric analysis approach. Based on bibliographic records retrieved from the Web of Science database, the study describes the periodic growth of literature, scientific fields and journals, author productivity and collaborations, institutions and countries, and topical focus and uses article citation analysis to identify the most influential works in this research field during the period of 1903 to 2012.
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Environmental factors that influence the association of an earthworm (Lumbricus terrestris L.) and an annual weed (Ambrosia Trifida L.) in no-till agricultural fields across the eastern U.S. Corn Belt
Agriculture Ecosystems & Environment, 2010Co-Authors: Brian J. Schutte, S. Kent Harrison, Jianyang Liu, Adam S. Davis, Emilie E. RegnierAbstract:Abstract The earthworm, Lumbricus terrestris L., caches seeds of the agricultural weed Ambrosia Trifida L. in its burrow, providing seeds with a protected overwintering site. Seedlings subsequently emerge from the burrows, resulting in an association of the two species (hereafter “LtAt association”). Although populations of these species frequently co-exist in no-till agricultural fields in the eastern U.S. Corn Belt, an association is not always evident. To identify environmental influences on the LtAt association, 30 no-till agricultural fields were surveyed across the eastern U.S. Corn Belt during spring 2007, 2008 and 2009. The LtAt association occurred across states and soil types, but the strength of the association varied with climate differences during the previous September through March. The strongest environmental driver of LtAt association was frequency of “moderate rain day” (MRD; day that received 12.8–25.3 mm of precipitation), with a 1-day increase in MRD frequency increasing the odds of LtAt association by a factor of 1.42. Thus, the potential for L. terrestris to cache seeds and facilitate seedling recruitment is increased by precipitation frequency and amount during September through March. These results highlight the importance of climate variation within a region in driving trophic interactions that regulate weed population dynamics.
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Giant ragweed (Ambrosia Trifida) canopy architecture and interference studies in soybean (Glycine max)
Weed Technology, 1994Co-Authors: Theodore M. Webster, Emilie E. Regnier, Mark M. Loux, S. Kent HarrisonAbstract:Field experiments were established at Columbus and near South Charleston, OH to determine the effects of giant ragweed population density on soybean yield and to characterize the development of giant ragweed grown in 76-cm soybean rows. An economic threshold was calculated for Ohio using a common treatment for giant ragweed control in soybean. A cost of $41/ha was estimated for a farmer to apply 0.56 kg/ha bentazon plus 0.28 kg/ha fomesafen plus COC (1.25% v/v). Assuming a soybean value of $0.22/kg, the cost of control was equivalent to 5.4 and 7.1% of the soybean yield in 1991 and 1992, respectively, which corresponded to the yield loss caused by 0.08 and 0.03 giant ragweed plants/M2. The competitiveness of giant ragweed can be at least partly attributed to its ability to initiate and maintain axillary leaves and branches within the shaded confines of the soybean canopy. Nomenclature: Bentazon, 3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide; fomesafen, 5-[2chloro-4-(trifluoromethyl)phenoxy-N-(methylsulfonyl)-2-nitrobenzamide; giant ragweed, Ambrosia Trifida L. #3 AMBTR; soybean, Glycine max (L.) Merr. 'Pella 88,' 'Resnik,' 'Countrymark 343.' Additional index words: Branching, competition, competitive threshold density, leaf abscission, leaf area, nodes.
S. Kent Harrison - One of the best experts on this subject based on the ideXlab platform.
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A mosaic of phenotypic variation in giant ragweed (Ambrosia Trifida): Local- and continental-scale patterns in a range-expanding agricultural weed.
Evolutionary applications, 2018Co-Authors: Stephen M. Hovick, S. Kent Harrison, Andrea Mcardle, Emilie E. RegnierAbstract:Spatial patterns of trait variation across a species' range have implications for population success and evolutionary change potential, particularly in range-expanding and weedy species that encounter distinct selective pressures at large and small spatial scales simultaneously. We investigated intraspecific trait variation in a common garden experiment with giant ragweed (Ambrosia Trifida), a highly variable agricultural weed with an expanding geographic range and broad ecological amplitude. Our study included paired populations from agricultural and natural riparian habitats in each of seven regions ranging east to west from the core of the species' distribution in central Ohio to southeastern Minnesota, which is nearer the current invasion front. We observed trait variation across both large- and small-scale putative selective gradients. At large scales, giant ragweed populations from the westernmost locations were nearly four times more fecund and had a nearly 50% increase in reproductive allocation compared to populations from the core. The degree of surface texture on fruits also declined from east to west. Greater fecundity in the west represents a putative trade-off between fruit size and fruit number across the study region, although no such trade-off was found across individual plants. This pattern may effectively result in greater propagule pressure closer to the invasion front. At smaller spatial scales, plants from agricultural populations emerged later and were smaller than plants from riparian populations. However, because plants from agricultural populations allocated more biomass to reproduction, total fecundity did not differ across habitats. Our emergence data are consistent with previous observations showing delayed emergence in agricultural compared to natural populations; thus evolutionary change may be predictable as giant ragweed continues spreading into agricultural fields throughout North America. These shifts in life-history strategy apparently bear no fecundity cost, suggesting that giant ragweed's success can be attributed at least in part to its substantial adaptive potential.
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Bibliometric Analysis of the Literature on Giant Ragweed (Ambrosia Trifida L.)
Journal of Agricultural & Food Information, 2013Co-Authors: Florian Diekmann, Robert A. Ford, S. Kent Harrison, Emilie E. Regnier, Ramaro VenkateshAbstract:Giant ragweed (Ambrosia Trifida L.) has become one of the most persistent and problematic weeds to farmers and allergy sufferers in North America over the last decades. This study aims to identify and assess the scholarly literature using a bibliometric analysis approach. Based on bibliographic records retrieved from the Web of Science database, the study describes the periodic growth of literature, scientific fields and journals, author productivity and collaborations, institutions and countries, and topical focus and uses article citation analysis to identify the most influential works in this research field during the period of 1903 to 2012.
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Environmental factors that influence the association of an earthworm (Lumbricus terrestris L.) and an annual weed (Ambrosia Trifida L.) in no-till agricultural fields across the eastern U.S. Corn Belt
Agriculture Ecosystems & Environment, 2010Co-Authors: Brian J. Schutte, S. Kent Harrison, Jianyang Liu, Adam S. Davis, Emilie E. RegnierAbstract:Abstract The earthworm, Lumbricus terrestris L., caches seeds of the agricultural weed Ambrosia Trifida L. in its burrow, providing seeds with a protected overwintering site. Seedlings subsequently emerge from the burrows, resulting in an association of the two species (hereafter “LtAt association”). Although populations of these species frequently co-exist in no-till agricultural fields in the eastern U.S. Corn Belt, an association is not always evident. To identify environmental influences on the LtAt association, 30 no-till agricultural fields were surveyed across the eastern U.S. Corn Belt during spring 2007, 2008 and 2009. The LtAt association occurred across states and soil types, but the strength of the association varied with climate differences during the previous September through March. The strongest environmental driver of LtAt association was frequency of “moderate rain day” (MRD; day that received 12.8–25.3 mm of precipitation), with a 1-day increase in MRD frequency increasing the odds of LtAt association by a factor of 1.42. Thus, the potential for L. terrestris to cache seeds and facilitate seedling recruitment is increased by precipitation frequency and amount during September through March. These results highlight the importance of climate variation within a region in driving trophic interactions that regulate weed population dynamics.
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Giant ragweed (Ambrosia Trifida) canopy architecture and interference studies in soybean (Glycine max)
Weed Technology, 1994Co-Authors: Theodore M. Webster, Emilie E. Regnier, Mark M. Loux, S. Kent HarrisonAbstract:Field experiments were established at Columbus and near South Charleston, OH to determine the effects of giant ragweed population density on soybean yield and to characterize the development of giant ragweed grown in 76-cm soybean rows. An economic threshold was calculated for Ohio using a common treatment for giant ragweed control in soybean. A cost of $41/ha was estimated for a farmer to apply 0.56 kg/ha bentazon plus 0.28 kg/ha fomesafen plus COC (1.25% v/v). Assuming a soybean value of $0.22/kg, the cost of control was equivalent to 5.4 and 7.1% of the soybean yield in 1991 and 1992, respectively, which corresponded to the yield loss caused by 0.08 and 0.03 giant ragweed plants/M2. The competitiveness of giant ragweed can be at least partly attributed to its ability to initiate and maintain axillary leaves and branches within the shaded confines of the soybean canopy. Nomenclature: Bentazon, 3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide; fomesafen, 5-[2chloro-4-(trifluoromethyl)phenoxy-N-(methylsulfonyl)-2-nitrobenzamide; giant ragweed, Ambrosia Trifida L. #3 AMBTR; soybean, Glycine max (L.) Merr. 'Pella 88,' 'Resnik,' 'Countrymark 343.' Additional index words: Branching, competition, competitive threshold density, leaf abscission, leaf area, nodes.
