Genetic architecture underlying HPPD-inhibitor resistance in a Nebraska Amaranthus tuberculatus population

BACKGROUND: Amaranthus tuberculatus is a primary driver weed species throughout the American Midwest. Inhibitors of 4-hydroxyphenylpyruvate dioxygenase (HPPD) are an important chemistry for weed management in numerous cropping systems. Here, we characterize the genetic architecture underlying the HPPD-inhibitor resistance trait in an A. tuberculatus population (NEB). RESULTS: Dose-response studies of an F1 generation identified HPPD-inhibitor resistance as a dominant trait with a resistance/sensitive ratio of 15.0-21.1. Segregation analysis in a pseudo-F2 generation determined the trait is moderately heritable (H2 = 0.556), and complex. Bulk segregant analysis and validation with molecular markers identified two quantitative trait loci (QTL), one on each of Scaffold 4 and 12. CONCLUSIONS: Resistance to HPPD-inhibitors is a complex, largely dominant trait within the NEB population. Two large-effect QTL were identified controlling HPPD-inhibitor resistance in A. tuberculatus. This is the first QTL mapping study to characterize herbicide resistance in a weedy species.

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Weed Management with Glyphosate- and Glufosinate-Based Systems in PHY 485 WRF Cotton

Weed Technology ◽

10.1614/wt-d-10-00008.1 ◽

2011 ◽

Vol 25 (2) ◽

pp. 183-191 ◽

Cited By ~ 31

Author(s):

Jared R. Whitaker ◽

Alan C. York ◽

David L. Jordan ◽

A. Stanley Culpepper

Keyword(s):

Weed Control ◽

Weed Management ◽

Fiber Quality ◽

Palmer Amaranth ◽

Weed Species ◽

Crop Tolerance ◽

The North ◽

Annual Grasses ◽

Resistance Trait ◽

Cotton Belt

Glyphosate-resistant (GR) Palmer amaranth has become a serious pest in parts of the Cotton Belt. Some GR cotton cultivars also contain the WideStrike™ insect resistance trait, which confers tolerance to glufosinate. Use of glufosinate-based management systems in such cultivars could be an option for managing GR Palmer amaranth. The objective of this study was to evaluate crop tolerance and weed control with glyphosate-based and glufosinate-based systems in PHY 485 WRF cotton. The North Carolina field experiment compared glyphosate and glufosinate alone and in mixtures applied twice before four- to six-leaf cotton. Additional treatments included glyphosate and glufosinate mixed withS-metolachlor or pyrithiobac applied to one- to two-leaf cotton followed by glyphosate or glufosinate alone on four- to six-leaf cotton. All treatments received a residual lay-by application. Excellent weed control was observed from all treatments on most weed species. Glyphosate was more effective than glufosinate on glyphosate-susceptible (GS) Palmer amaranth and annual grasses, while glufosinate was more effective on GR Palmer amaranth. Annual grass and GS Palmer amaranth control by glyphosate plus glufosinate was often less than control by glyphosate alone but similar to or greater than control by glufosinate alone, while mixtures were more effective than either herbicide alone on GR Palmer amaranth. Glufosinate caused minor and transient injury to the crop, but no differences in cotton yield or fiber quality were noted. This research demonstrates glufosinate can be applied early in the season to PHY 485 WRF cotton without concern for significant adverse effects on the crop. Although glufosinate is often less effective than glyphosate on GS Palmer amaranth, GR Palmer amaranth can be controlled with well-timed applications of glufosinate. Use of glufosinate in cultivars with the WideStrike trait could fill a significant void in current weed management programs for GR Palmer amaranth in cotton.

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Competitiveness of Herbicide-Resistant Waterhemp (Amaranthus tuberculatus) with Soybean

Weed Science ◽

10.1017/wsc.2018.45 ◽

2018 ◽

Vol 66 (6) ◽

pp. 729-737 ◽

Cited By ~ 2

Author(s):

Thomas R. Butts ◽

Bruno C. Vieira ◽

Débora O. Latorre ◽

Rodrigo Werle ◽

Greg R. Kruger

Keyword(s):

Weed Management ◽

Management Practices ◽

Cropping Systems ◽

Biomass Accumulation ◽

Stem Diameter ◽

The Other ◽

Harvest Time ◽

Herbicide Resistant ◽

Amaranthus Tuberculatus ◽

Soybean Plants

AbstractWaterhemp [Amaranthus tuberculatus(Moq.) J. D. Sauer] is a troublesome weed occurring in cropping systems throughout the U.S. Midwest with an ability to rapidly evolve herbicide resistance that could be associated with competitive disadvantages. Little research has investigated the competitiveness of differentA. tuberculatuspopulations under similar environmental conditions. The objectives of this study were to evaluate: (1) the interspecific competitiveness of three herbicide-resistantA. tuberculatuspopulations (2,4-D and atrazine resistant [2A-R], glyphosate and protoporphyrinogen oxidase [PPO]-inhibitor resistant [GP-R], and 2,4-D, atrazine, glyphosate, and PPO-inhibitor susceptible [2AGP-S]) with soybean [Glycine max(L.) Merr.]; and (2) the density-dependent response of eachA. tuberculatuspopulation within a constant soybean population in a greenhouse environment.Amaranthus tuberculatuscompetitiveness with soybean was evaluated across five target weed densities of 0, 2, 4, 8, and 16 plants pot−1(equivalent to 0, 20, 40, 80, and 160 plants m−2) with 3 soybean plants pot−1(equivalent to 300,000 plants ha−1). At the R1 soybean harvest time, no difference in soybean biomass was observed acrossA. tuberculatuspopulations. AtA. tuberculatusdensities <8 plants pot−1, the 2AGP-S population had the greatest biomass and stem diameter per plant. At the R7 harvest time, the 2AGP-S population caused the greatest loss in soybean biomass and number of pods compared with the other populations at densities of <16 plants pot−1. The 2AGP-S population had greater early-season biomass accumulation and stem diameter compared with the otherA. tuberculatuspopulations, which resulted in greater late-season reduction in soybean biomass and number of pods. This research indicates there may be evidence of interspecific competitive fitness cost associated with the evolution of 2,4-D, atrazine, glyphosate, and PPO-inhibitor resistance inA. tuberculatus. Focus should be placed on effectively using cultural weed management practices to enhance crop competitiveness, especially early in the season, to increase suppression of herbicide-resistantA. tuberculatus.

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The effect of weed management systems and location on arable weed species communities in glyphosate-resistant cropping systems

Applied Vegetation Science ◽

10.1111/avsc.12039 ◽

2013 ◽

Vol 16 (4) ◽

pp. 676-687 ◽

Cited By ~ 9

Author(s):

David J. Gibson ◽

Karla L. Gage ◽

Joseph L. Matthews ◽

Bryan G. Young ◽

Micheal D.K. Owen ◽

...

Keyword(s):

Weed Management ◽

Cropping Systems ◽

Management Systems ◽

Weed Species ◽

Arable Weed

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Assessing weeds at risk of evolving glyphosate resistance in Australian sub-tropical glyphosate-resistant cotton systems

Crop and Pasture Science ◽

10.1071/cp11201 ◽

2011 ◽

Vol 62 (11) ◽

pp. 1002 ◽

Cited By ~ 22

Author(s):

Jeff Werth ◽

David Thornby ◽

Steve Walker

Keyword(s):

High Risk ◽

Weed Management ◽

Management Practices ◽

Cropping Systems ◽

Cropping System ◽

Glyphosate Resistance ◽

Management Approach ◽

Weed Species ◽

Summer Fallow ◽

Very High

Glyphosate resistance will have a major impact on current cropping practices in glyphosate-resistant cotton systems. A framework for a risk assessment for weed species and management practices used in cropping systems with glyphosate-resistant cotton will aid decision making for resistance management. We developed this framework and then assessed the biological characteristics of 65 species and management practices from 50 cotton growers. This enabled us to predict the species most likely to evolve resistance, and the situations in which resistance is most likely to occur. Species with the highest resistance risk were Brachiaria eruciformis, Conyza bonariensis, Urochloa panicoides, Chloris virgata, Sonchus oleraceus and Echinochloa colona. The summer fallow and non-irrigated glyphosate-resistant cotton were the highest risk phases in the cropping system. When weed species and management practices were combined, C. bonariensis in summer fallow and other winter crops were at very high risk. S. oleraceus had very high risk in summer and winter fallow, as did C. virgata and E. colona in summer fallow. This study enables growers to identify potential resistance risks in the species present and management practices used on their farm, which will to facilitate a more targeted weed management approach to prevent development of glyphosate resistance.

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Nontarget-Site Resistance to ALS Inhibitors in Waterhemp (Amaranthus tuberculatus)

Weed Science ◽

10.1614/ws-d-14-00139.1 ◽

2015 ◽

Vol 63 (2) ◽

pp. 399-407 ◽

Cited By ~ 31

Author(s):

Jiaqi Guo ◽

Chance W. Riggins ◽

Nicholas E. Hausman ◽

Aaron G. Hager ◽

Dean E. Riechers ◽

...

Keyword(s):

Acetolactate Synthase ◽

Enzyme Assays ◽

Whole Plant ◽

Site Of Action ◽

Amaranthus Tuberculatus ◽

Resistance Trait ◽

Als Inhibitors ◽

Moderate Resistance ◽

Inhibitor Resistance ◽

Als Inhibitor

A waterhemp population (MCR) previously characterized as resistant to 4-hydroxyphenylpyruvate dioxygenase and photosystem II inhibitors demonstrated both moderate and high levels of resistance to acetolactate synthase (ALS) inhibitors. Plants from the MCR population exhibiting high resistance to ALS inhibitors contained the commonly found Trp574Leu ALS amino acid substitution, whereas plants with only moderate resistance did not have this substitution. A subpopulation (JG11) was derived from the MCR population in which the moderate-resistance trait was isolated from the Trp574Leu mutation. Results from DNA sequencing and ALS enzyme assays demonstrated that resistance to ALS inhibitors in the JG11 population was not due to an altered site of action. This nontarget-site ALS-inhibitor resistance was characterized with whole-plant dose–response experiments using herbicides from each of the five commercialized families of ALS-inhibiting herbicides. Resistance ratios ranging from 3 to 90 were obtained from the seven herbicides evaluated. Nontarget-site resistance to ALS has been rarely documented in eudicot weeds, and adds to the growing list of resistance traits evolved in waterhemp.

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Buckwheat Residue Effects on Emergence and Growth of Weeds in Winter-Wheat (Triticum aestivum) Cropping Systems

Weed Science ◽

10.1614/ws-d-11-00006.1 ◽

2011 ◽

Vol 59 (4) ◽

pp. 567-573 ◽

Cited By ~ 12

Author(s):

Virender Kumar ◽

Daniel C. Brainard ◽

Robin R. Bellinder ◽

Russell R. Hahn

Keyword(s):

New York ◽

Winter Wheat ◽

Weed Management ◽

Cropping Systems ◽

Soil Surface ◽

Bare Soil ◽

Weed Species ◽

Winter Annual ◽

Winter Annual Weeds ◽

Annual Weeds

Field and pot studies were conducted in Central New York to determine the potential weed-management benefits of a buckwheat cover crop grown before winter wheat. Specific objectives were to determine buckwheat residue effects on (1) emergence and growth of winter annual weeds; (2) wheat establishment and yield; and (3) emergence of summer annual weeds in the spring following overwinter seed burial. In a field study, buckwheat was sown at two timings (July or August), mowed, and either incorporated or left on the soil surface. Winter wheat was drilled into buckwheat residue in September and weed and crop growth were monitored. In a complementary pot study, four winter annual weeds were sown in soil removed from buckwheat and bare-soil plots at 0 or 15 d after incorporation and monitored for emergence and early growth. To assess buckwheat residue effects on spring emergence from overwintering seeds, seeds of three weed species were buried in buckwheat residue and bare-soil plots in the fall, exhumed in April, and evaluated for emergence. To investigate the mechanism for possible effects of buckwheat residue on overwintering seeds, two levels each of seed treatment (none or fungicide) and fertilization (none or 170 kg ha−1) were applied before burial. Buckwheat residue had no negative effect on wheat yields but suppressed emergence (22 to 72%) and growth (0 to 95%) of winter annual weeds, although effects were often small and inconsistent. Buckwheat residue had no effect on the emergence of buried weed seeds in spring. However, fungicide treatment enhanced the emergence of Powell amaranth seeds by 12.5 to 25.5% and of barnyardgrass seeds by 0 to 12%. Our results suggest that buckwheat residue can contribute to weed management in wheat cropping systems, but that further studies investigating the mechanistic basis for the inconsistent selective effects of buckwheat residue on weeds are needed before buckwheat use can be optimized.

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Carrots and Sticks: Incentives and Regulations for Herbicide Resistance Management and Changing Behavior

Weed Science ◽

10.1614/ws-d-15-00171.1 ◽

2016 ◽

Vol 64 (SP1) ◽

pp. 627-640 ◽

Cited By ~ 13

Author(s):

Michael Barrett ◽

John Soteres ◽

David Shaw

Keyword(s):

United States ◽

Herbicide Resistance ◽

Weed Management ◽

Cropping Systems ◽

Wide Spectrum ◽

Resistance Management ◽

Herbicide Tolerance ◽

The United States ◽

Weed Species ◽

Agricultural Community

Although the problem of herbicide resistance is not new, the widespread evolution of glyphosate resistance in weed species such as Palmer amaranth (Amaranthus palmeriS. Wats.), common waterhemp (Amaranthus rudisSauer), and kochia [Kochia scoparia(L.) Schrad.] raised awareness throughout the agricultural community of herbicide resistance as a problem. Glyphosate-resistant weeds resulted in the loss of a simple, single herbicide option to control a wide spectrum of weeds that gave efficacious and economical weed management in corn (Zea maysL.), soybean [Glycine max(L.) Merr.], and cotton (Gossypium hirsutumL.) crops engineered for tolerance to this herbicide and planted over widespread areas of the South and Midwest of the United States. Beyond these crops, glyphosate is used for vegetation management in other cropping systems and in noncrop areas across the United States, and resistance to this herbicide threatens its continued utility in all of these situations. This, combined with the development of multiple herbicide-resistant weeds and the lack of commercialization of herbicides with new mechanisms of action over the past years (Duke 2012), caused the weed science community to realize that stewardship of existing herbicide resources, extending their useful life as long as possible, is imperative. Further, while additional herbicide tolerance traits are being incorporated into crops, weed management in these crops will still be based upon using existing, old, herbicide chemistries.

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Effect of roller-crimper technology on weed management in organic zucchini production in a Mediterranean climate zone

Renewable Agriculture and Food Systems ◽

10.1017/s1742170515000046 ◽

2015 ◽

Vol 31 (2) ◽

pp. 111-121 ◽

Cited By ~ 11

Author(s):

Corrado Ciaccia ◽

Stefano Canali ◽

Gabriele Campanelli ◽

Elena Testani ◽

Francesco Montemurro ◽

...

Keyword(s):

Weed Control ◽

Cover Crops ◽

Weed Management ◽

Cover Crop ◽

Cropping Systems ◽

Central Italy ◽

Competitive Balance ◽

Weed Species ◽

Wide Range ◽

Cropping Seasons

AbstractIntegrating cover crops into vegetable cropping systems can provide a wide range of ecological services, of which weed management is a key component. Cover crop effects on weed control, however, are dependent on termination methods and weed species present in specific cropping seasons. A 2-year weed management experiment with two cultivars of organic zucchini (Cucurbita pepo L.) in central Italy was carried out to compare the effect of a barley (Hordeum distichum L.) cover crop terminated with a modified roller-crimper (RC) to incorporated barley as green manure (GM) and a tilled control left fallow (FA) in the off-season. The effects of cover-crop management on crop competitiveness, yields and weed populations were evaluated by direct measurement, visual estimation and competition index methods. Results showed a significant reduction in weed biomass (>80%) and weed abundance with the RC compared to the GM and FA treatments. Moreover, the RC barley mulch maintained weed control in zucchini plots even under high weed pressure, as determined by the agronomic tolerance to competition (ATC) value of 67% in the RC treatment compared to 40 and 34% in the FA and GM treatments, respectively, averaged over both years of the experiment. The competitive balance (Cb), which quantified the ability of the zucchini crop to compete with weed populations, was also greater (+0.37) in the RC treatment compared to FA (−0.87) and GM (−0.69) treatments over the same period. Zucchini crop biomass was greatest in the RC treatment in 2011. Zucchini fruit yields varied from an average over both years of 1.4 Mg ha−1 in the RC treatment to 0.7 Mg ha−1 in the GM treatment, but yields in the FA treatment, 1.2 Mg ha−1, did not differ from the RC treatment. No differences in yield between ‘Dietary’ and ‘Every’ zucchini, or any significant interactions between cultivar and cover management related to fruit biomass, were observed. Our findings suggested the viability of the modified RC in creating a barley cover-crop mulch to effectively manage weeds and enhance yields in transplanted zucchini.

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Effect of Crop Residues on Weed Emergence

Agronomy ◽

10.3390/agronomy11010163 ◽

2021 ◽

Vol 11 (1) ◽

pp. 163

Author(s):

Nebojša Nikolić ◽

Donato Loddo ◽

Roberta Masin

Keyword(s):

Weed Management ◽

Crop Residues ◽

Cropping Systems ◽

Chenopodium Album ◽

Seedling Emergence ◽

Amaranthus Retroflexus ◽

Weed Species ◽

Field Quantity ◽

Crop Fields ◽

No Till

Weed behaviour in crop fields has been extensively studied; nevertheless, limited knowledge is available for particular cropping systems, such as no-till systems. Improving weed management under no-till conditions requires an understanding of the interaction between crop residues and the seedling emergence process. This study aimed to evaluate the influence of maize and wheat residues, applied in three different quantities (1, the field quantity, 0.5, and 1.5-fold amounts of the field quantity), on the emergence of eight weed species: Abutilon theophrasti, Amaranthus retroflexus, Chenopodium album, Digitaria sanguinalis, Echinochloa crus-galli, Setaria pumila, Sonchus oleraceus, and Sorghum halepense. The experiment was conducted over two consecutive years. The results showed that the quantities 1 and 1.5 could suppress seedling emergence by 20 and 44%, respectively, while the quantity 0.5 seems to promote emergence by 22% compared with the control without residues. Weed species showed different responses to crop residues, from C. album showing 56% less emergence to S. halepense showing a 44% higher emergence than the control without residues. Different meteorological conditions in the two-year experiment also exhibited a significant influence on weed species emergence.

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