Zichang Zhang, Hongchun Wang, Jingjing Cao, Gui-quan Li, B. Chauhan
Abstract Alkali barnyardgrass [Echinochloa crus-galli var. zelayensis (Kunth) Hitchc] and junglerice [Echinochloa colona (L.) Link] are problematic annual weeds in direct-seeded rice (Oryza sativa L.) fields in China. The emergence ecology of the two weed species may differ in response to environmental factors. Laboratory and screenhouse experiments were conducted to evaluate the effects of light, burial depth, mulching with wheat (Triticum aestivum L.) residue, and time and depth of flooding on the emergence of the two weed species collected from Nanjing, China. Light strongly increased seed germination. Under dark conditions, E. crus-galli seed germination (85%) was higher than that of E. colona (70%). The seeds of both species exhibited the greatest germination (90% for E. crus-galli and 80% for E. colona) when sown on the soil surface, and emergence decreased with increasing soil burial depth. Burial depths of 2.2 and 1.4 cm reduced seedling emergence by 50% for E. crus-galli and E. colona, respectively. No emergence was found at a depth of 6 cm. The seedling emergence for E. colona was lower than for E. crus-galli at the same soil burial depth. Mulching with wheat residue considerably reduced the seedling emergence and aboveground biomass of both species. The inhibitory effect of mulching with wheat residue on E. colona was more notable than on E. crus-galli. Early and deep flooding significantly suppressed the emergence, height, and biomass of E. crus-galli and E. colona, especially E. colona. The results gained from this study could provide fundamental ecological knowledge for managing Echinochloa species in direct-seeded rice systems.
{"title":"Seed Biology of Alkali Barnyardgrass (Echinochloa crus-galli var. Zelayensis) and Junglerice (Echinochloa colona) for Improved Management in Direct-Seeded Rice","authors":"Zichang Zhang, Hongchun Wang, Jingjing Cao, Gui-quan Li, B. Chauhan","doi":"10.1017/wsc.2023.8","DOIUrl":"https://doi.org/10.1017/wsc.2023.8","url":null,"abstract":"Abstract Alkali barnyardgrass [Echinochloa crus-galli var. zelayensis (Kunth) Hitchc] and junglerice [Echinochloa colona (L.) Link] are problematic annual weeds in direct-seeded rice (Oryza sativa L.) fields in China. The emergence ecology of the two weed species may differ in response to environmental factors. Laboratory and screenhouse experiments were conducted to evaluate the effects of light, burial depth, mulching with wheat (Triticum aestivum L.) residue, and time and depth of flooding on the emergence of the two weed species collected from Nanjing, China. Light strongly increased seed germination. Under dark conditions, E. crus-galli seed germination (85%) was higher than that of E. colona (70%). The seeds of both species exhibited the greatest germination (90% for E. crus-galli and 80% for E. colona) when sown on the soil surface, and emergence decreased with increasing soil burial depth. Burial depths of 2.2 and 1.4 cm reduced seedling emergence by 50% for E. crus-galli and E. colona, respectively. No emergence was found at a depth of 6 cm. The seedling emergence for E. colona was lower than for E. crus-galli at the same soil burial depth. Mulching with wheat residue considerably reduced the seedling emergence and aboveground biomass of both species. The inhibitory effect of mulching with wheat residue on E. colona was more notable than on E. crus-galli. Early and deep flooding significantly suppressed the emergence, height, and biomass of E. crus-galli and E. colona, especially E. colona. The results gained from this study could provide fundamental ecological knowledge for managing Echinochloa species in direct-seeded rice systems.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"71 1","pages":"112 - 123"},"PeriodicalIF":2.5,"publicationDate":"2023-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43741238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Seefeldt, Toby M. Una, D. McMoran, B. Maupin, E. Myhre, Deirdre Griffin‐LaHue
Abstract Cover cropping is a suggested soil conservation practice widely investigated in cropping systems. Cover crops suppress weeds and often are part of an integrated weed management plan that could lead to reduced herbicide use and possibly reduce the weed seedbank. Winter brassica cover crops are popular in the eastern Washington potato (Solanum tuberosum L.) production region, but in western Washington, the production of brassica seed crops presents disease issues along with the risk of cross-pollination, which limits the use of brassica cover crops. Research for this article was conducted in two trials from 2018 to 2020 and 2019 to 2021in Mount Vernon, Washington, to identify winter cover crops compatible with regional restrictions and climatic challenges in western Washington cropping systems. Treatments including a no-cover control, eight single species (including brassicas, grasses, and legumes), and a grass–legume mixture were investigated. Cover crop and weed biomass production were measured, and percent ground cover for cover crops and weeds by species was estimated. Cover crop biomass and weed suppression varied by year due to variable environments, but annual ryegrass (Lolium multiflorum Lam.) and the mixture were most consistent in producing large amounts of biomass and reducing weed biomass and cover in all years. The variability of percent weed cover response to environment was ameliorated when weed cover was normalized within each year's control.
{"title":"Impacts of Two Years of Autumn Cover Crops in Northwestern Washington on Winter Annual Weed Populations","authors":"S. Seefeldt, Toby M. Una, D. McMoran, B. Maupin, E. Myhre, Deirdre Griffin‐LaHue","doi":"10.1017/wsc.2023.7","DOIUrl":"https://doi.org/10.1017/wsc.2023.7","url":null,"abstract":"Abstract Cover cropping is a suggested soil conservation practice widely investigated in cropping systems. Cover crops suppress weeds and often are part of an integrated weed management plan that could lead to reduced herbicide use and possibly reduce the weed seedbank. Winter brassica cover crops are popular in the eastern Washington potato (Solanum tuberosum L.) production region, but in western Washington, the production of brassica seed crops presents disease issues along with the risk of cross-pollination, which limits the use of brassica cover crops. Research for this article was conducted in two trials from 2018 to 2020 and 2019 to 2021in Mount Vernon, Washington, to identify winter cover crops compatible with regional restrictions and climatic challenges in western Washington cropping systems. Treatments including a no-cover control, eight single species (including brassicas, grasses, and legumes), and a grass–legume mixture were investigated. Cover crop and weed biomass production were measured, and percent ground cover for cover crops and weeds by species was estimated. Cover crop biomass and weed suppression varied by year due to variable environments, but annual ryegrass (Lolium multiflorum Lam.) and the mixture were most consistent in producing large amounts of biomass and reducing weed biomass and cover in all years. The variability of percent weed cover response to environment was ameliorated when weed cover was normalized within each year's control.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"71 1","pages":"150 - 159"},"PeriodicalIF":2.5,"publicationDate":"2023-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45139514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. G. Vázquez-García, P. Castro, A. Royo‐Esnal, Candelario Palma-Bautista, J. Torra, R. de Prado
Abstract Glyphosate resistance is spreading in Spain and Portugal due to excessive herbicide use, in both annual and perennial crops. Compact brome (Bromus madritensis L.) is increasing in frequency in these different cropping systems when under conservation agriculture, particularly when glyphosate fails to control it. Fourteen populations from different areas in the Iberian Peninsula were confirmed as being B. madritensis using simple sequence repeat markers and clearly separated from the closely related species red brome (Bromus rubens L.) and ripgut brome (Bromus diandrus Roth). Six B. madritensis populations were classified as resistant, according to both their shikimic acid accumulation levels and their resistance factors based on LD50 or GR50 (values between 4 and 8). Populations with higher resistance factors also showed lower shikimic acid concentrations. Moreover, these resistant populations were able to survive the minimum registered dose for glyphosate in Spain in perennial crops (1,080 g ae ha–1, five populations) or in arable crops before seeding for annual weeds (540 g ae ha–1, one population), under both greenhouse and field conditions. The trials carried out in a glyphosate-resistant field during 2 consecutive years showed that acceptable control (≥90%) was only consistently achieved 90 d after application for preemergence treatment with flazasulfuron in a tank mix with glyphosate, while control with postemergence treatments, such as propaquizafop plus glyphosate, was below 80%. This research describes the first herbicide-resistance report for the weed species B. madritensis, confirming the presence of glyphosate-resistant populations mainly in perennial cropping systems but also in winter cereals from Spain. Due to the limited chemical tools to manage these populations, there is an urgent need for farmers to implement integrated weed management strategies.
摘要草甘膦耐药性正在西班牙和葡萄牙蔓延，原因是在一年生和多年生作物中过量使用除草剂。在保护性农业下，紧凑型溴化物（Bromus madritensis L.）在这些不同的种植系统中的频率越来越高，尤其是当草甘膦无法控制时。使用简单序列重复标记，来自伊比利亚半岛不同地区的14个种群被确认为马德里氏B.madritensis，并与亲缘关系密切的红雀麦（Bromus rubens L.）和里普古特雀麦（Bromus diandrus Roth）明显分离。根据其莽草酸积累水平和基于LD50或GR50的抗性因子（值在4-8之间），将6个马德里氏杆菌种群归类为抗性。具有较高抗性因子的群体也表现出较低的莽草酸浓度。此外，在西班牙，在温室和田间条件下，这些抗性群体能够在多年生作物（1080 g ae ha–1，5个群体）或可耕地作物中存活草甘膦的最低注册剂量，然后播种一年生杂草（540 g ae ha-1，1个群体）。连续2年在抗草甘膦田地中进行的试验表明，在与草甘膦混合的罐中应用flazasulfuron进行出苗前处理后90天，才始终达到可接受的控制（≥90%），而采用出苗后处理（如原奎福加草甘膦）的控制低于80%。这项研究描述了第一份针对马德里氏B.madritensis杂草的除草剂抗性报告，证实了草甘膦抗性种群主要存在于多年生种植系统中，也存在于西班牙的冬季谷物中。由于管理这些种群的化学工具有限，农民迫切需要实施综合杂草管理战略。
{"title":"First Report of a Wide Distribution of Glyphosate-Resistant Compact Brome (Bromus madritensis) in the Iberian Peninsula: Confirmation and Field Management","authors":"J. G. Vázquez-García, P. Castro, A. Royo‐Esnal, Candelario Palma-Bautista, J. Torra, R. de Prado","doi":"10.1017/wsc.2023.9","DOIUrl":"https://doi.org/10.1017/wsc.2023.9","url":null,"abstract":"Abstract Glyphosate resistance is spreading in Spain and Portugal due to excessive herbicide use, in both annual and perennial crops. Compact brome (Bromus madritensis L.) is increasing in frequency in these different cropping systems when under conservation agriculture, particularly when glyphosate fails to control it. Fourteen populations from different areas in the Iberian Peninsula were confirmed as being B. madritensis using simple sequence repeat markers and clearly separated from the closely related species red brome (Bromus rubens L.) and ripgut brome (Bromus diandrus Roth). Six B. madritensis populations were classified as resistant, according to both their shikimic acid accumulation levels and their resistance factors based on LD50 or GR50 (values between 4 and 8). Populations with higher resistance factors also showed lower shikimic acid concentrations. Moreover, these resistant populations were able to survive the minimum registered dose for glyphosate in Spain in perennial crops (1,080 g ae ha–1, five populations) or in arable crops before seeding for annual weeds (540 g ae ha–1, one population), under both greenhouse and field conditions. The trials carried out in a glyphosate-resistant field during 2 consecutive years showed that acceptable control (≥90%) was only consistently achieved 90 d after application for preemergence treatment with flazasulfuron in a tank mix with glyphosate, while control with postemergence treatments, such as propaquizafop plus glyphosate, was below 80%. This research describes the first herbicide-resistance report for the weed species B. madritensis, confirming the presence of glyphosate-resistant populations mainly in perennial cropping systems but also in winter cereals from Spain. Due to the limited chemical tools to manage these populations, there is an urgent need for farmers to implement integrated weed management strategies.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"71 1","pages":"95 - 103"},"PeriodicalIF":2.5,"publicationDate":"2023-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45374600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. F. Braga, Leandro Aparecido Chiconi, A. L. Bacha, G. H. de Almeida Teixeira, L. C. Cunha Junior, P. L. da Costa Aguiar Alves
Abstract The occurrence of weeds is one of the main factors limiting agricultural productivity. Studies on new techniques for the identification of these species can contribute to the development of proximal sensors, which in the future might be coupled to machines to optimize the performance of species-specific weed management. Thus, the objective of this study was to use near-infrared (NIR) spectroscopy and multivariate analysis to discriminate three morningglory species (Ipomoea spp.). The NIR spectra were collected from the leaves of the three weed species at the vegetative stage (up to five leaves), within the spectral band of 4,000 to 10,000 cm–1. The discrimination models were selected according to accuracy, sensitivity, specificity, and Youden's index and were analyzed with a validation data set (n = 135). The best results occurred when the selection of spectral bands associated with the use of preprocessing was performed. It was possible to obtain an accuracy of 99.3%, 98.5%, and 98.7% for ivyleaf morningglory (Ipomoea hederifolia L.), Japanese morningglory [Ipomoea nil (L.) Roth], and hairy woodrose [Merremia aegyptia (L.) Urb.], respectively. NIR spectroscopy associated with principal component analysis and linear discriminant analysis (PC-LDA) or partial least-squares regression with discriminant analysis (PLS-DA) can be used to discriminate Ipomoea spp.
{"title":"Discrimination of Morningglory Species (Ipomoea spp.) Using Near-Infrared Spectroscopy and Multivariate Analysis","authors":"A. F. Braga, Leandro Aparecido Chiconi, A. L. Bacha, G. H. de Almeida Teixeira, L. C. Cunha Junior, P. L. da Costa Aguiar Alves","doi":"10.1017/wsc.2023.6","DOIUrl":"https://doi.org/10.1017/wsc.2023.6","url":null,"abstract":"Abstract The occurrence of weeds is one of the main factors limiting agricultural productivity. Studies on new techniques for the identification of these species can contribute to the development of proximal sensors, which in the future might be coupled to machines to optimize the performance of species-specific weed management. Thus, the objective of this study was to use near-infrared (NIR) spectroscopy and multivariate analysis to discriminate three morningglory species (Ipomoea spp.). The NIR spectra were collected from the leaves of the three weed species at the vegetative stage (up to five leaves), within the spectral band of 4,000 to 10,000 cm–1. The discrimination models were selected according to accuracy, sensitivity, specificity, and Youden's index and were analyzed with a validation data set (n = 135). The best results occurred when the selection of spectral bands associated with the use of preprocessing was performed. It was possible to obtain an accuracy of 99.3%, 98.5%, and 98.7% for ivyleaf morningglory (Ipomoea hederifolia L.), Japanese morningglory [Ipomoea nil (L.) Roth], and hairy woodrose [Merremia aegyptia (L.) Urb.], respectively. NIR spectroscopy associated with principal component analysis and linear discriminant analysis (PC-LDA) or partial least-squares regression with discriminant analysis (PLS-DA) can be used to discriminate Ipomoea spp.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"71 1","pages":"104 - 111"},"PeriodicalIF":2.5,"publicationDate":"2023-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46425935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Jones, R. Andres, J. Dunne, R. León, W. Everman
Abstract Complaints of control failures with acetolactate synthase (ALS)- and protoporphyrinogen oxidase (PPO)-inhibiting herbicides on redroot pigweed (Amaranthus retroflexus L.) were reported in conventional soybean [Glycine max (L.) Merr.] fields in North Carolina. Greenhouse dose–response assays confirmed that the Camden County and Pasquotank County populations were less sensitive to ALS- and PPO-inhibiting herbicides compared with susceptible A. retroflexus populations, suggesting the evolution of resistance to these herbicides. Sanger sequencing of target genes determined the Camden County population carried a Trp-574-Leu mutation in the ALS gene and an Arg-98-Gly mutation in the PPX2 gene, while the Pasquotank County population carried a His-197-Pro mutation in the ALS gene (first documentation of the mutation in the Amaranthus genus), but no mutation was detected in the PPX2 gene. Single-nucleotide polymorphism (SNP) genotyping assays were developed to enable efficient screening of future control failures in order to limit the spread of these herbicide-resistant populations. In addition, preliminary testing of these assays revealed the three mutations were ubiquitous in the respective populations. These two populations represent the first confirmed cases of PPO-inhibiting herbicide-resistant A. retroflexus in the United States, as well as the first confirmed cases of this particular herbicide-resistance profile in A. retroflexus inhabiting North America. While no mutation was found in the PPX2 gene of the Pasquotank County population, we suggest that this population has evolved resistance to PPO-inhibiting herbicides, but the mechanism of resistance is to be determined.
{"title":"Confirmation and Detection of Novel Acetolactate Synthase- and Protoporphyrinogen Oxidase–Inhibiting Herbicide-Resistant Redroot Pigweed (Amaranthus retroflexus) Populations in North Carolina","authors":"E. Jones, R. Andres, J. Dunne, R. León, W. Everman","doi":"10.1017/wsc.2023.4","DOIUrl":"https://doi.org/10.1017/wsc.2023.4","url":null,"abstract":"Abstract Complaints of control failures with acetolactate synthase (ALS)- and protoporphyrinogen oxidase (PPO)-inhibiting herbicides on redroot pigweed (Amaranthus retroflexus L.) were reported in conventional soybean [Glycine max (L.) Merr.] fields in North Carolina. Greenhouse dose–response assays confirmed that the Camden County and Pasquotank County populations were less sensitive to ALS- and PPO-inhibiting herbicides compared with susceptible A. retroflexus populations, suggesting the evolution of resistance to these herbicides. Sanger sequencing of target genes determined the Camden County population carried a Trp-574-Leu mutation in the ALS gene and an Arg-98-Gly mutation in the PPX2 gene, while the Pasquotank County population carried a His-197-Pro mutation in the ALS gene (first documentation of the mutation in the Amaranthus genus), but no mutation was detected in the PPX2 gene. Single-nucleotide polymorphism (SNP) genotyping assays were developed to enable efficient screening of future control failures in order to limit the spread of these herbicide-resistant populations. In addition, preliminary testing of these assays revealed the three mutations were ubiquitous in the respective populations. These two populations represent the first confirmed cases of PPO-inhibiting herbicide-resistant A. retroflexus in the United States, as well as the first confirmed cases of this particular herbicide-resistance profile in A. retroflexus inhabiting North America. While no mutation was found in the PPX2 gene of the Pasquotank County population, we suggest that this population has evolved resistance to PPO-inhibiting herbicides, but the mechanism of resistance is to be determined.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"71 1","pages":"84 - 94"},"PeriodicalIF":2.5,"publicationDate":"2023-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41617904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anna S. Westbrook, Masoume Amirkhani, A. Taylor, Michael T. Loos, J. Losey, A. DiTommaso
Abstract Intensive agricultural crop production is typically associated with low biodiversity. Low biodiversity is associated with a deficit of ecosystem services, which may limit crop yield (e.g., low pollination of insect-pollinated crops) at the individual field level or exacerbate the landscape-level impacts of intensive agriculture. To increase biodiversity and enhance ecosystem services with minimal loss of crop production area, farmers can plant desirable non-crop species near crop fields. Adoption of this practice is limited by inefficiencies in existing establishment methods. We have developed a novel seed-molding method allowing non-crop species to be planted with a conventional corn (Zea mays L.) planter, reducing labor and capital costs associated with native species establishment. Common milkweed (Asclepias syriaca L.) was selected as a model native species, because Asclepias plants are the sole food source for monarch butterfly (Danaus plexippus L.) larvae. Stratified A. syriaca seeds were added to a mixture of binder (maltodextrin) and filler (diatomaceous earth and wood flour) materials in a 3D-printed mold with the dimensions of a corn seed. The resulting Multi-Seed Zea Pellets (MSZP), shaped like corn seeds, were tested against non-pelleted A. syriaca seeds in several indoor and outdoor pot experiments. Molding into MSZP did not affect percent emergence or time to emergence from a 2-cm planting depth. Intraspecific competition among seedlings that emerged from an MSZP did not differ from competition among seedlings that emerged from a cluster of non-pelleted seeds. These findings demonstrate the potential of MSZP technology as a precise and efficient method for increasing agroecosystem biodiversity.
{"title":"Multi-Seed Zea Pellets (MSZP) for Increasing Agroecosystem Biodiversity","authors":"Anna S. Westbrook, Masoume Amirkhani, A. Taylor, Michael T. Loos, J. Losey, A. DiTommaso","doi":"10.1017/wsc.2023.5","DOIUrl":"https://doi.org/10.1017/wsc.2023.5","url":null,"abstract":"Abstract Intensive agricultural crop production is typically associated with low biodiversity. Low biodiversity is associated with a deficit of ecosystem services, which may limit crop yield (e.g., low pollination of insect-pollinated crops) at the individual field level or exacerbate the landscape-level impacts of intensive agriculture. To increase biodiversity and enhance ecosystem services with minimal loss of crop production area, farmers can plant desirable non-crop species near crop fields. Adoption of this practice is limited by inefficiencies in existing establishment methods. We have developed a novel seed-molding method allowing non-crop species to be planted with a conventional corn (Zea mays L.) planter, reducing labor and capital costs associated with native species establishment. Common milkweed (Asclepias syriaca L.) was selected as a model native species, because Asclepias plants are the sole food source for monarch butterfly (Danaus plexippus L.) larvae. Stratified A. syriaca seeds were added to a mixture of binder (maltodextrin) and filler (diatomaceous earth and wood flour) materials in a 3D-printed mold with the dimensions of a corn seed. The resulting Multi-Seed Zea Pellets (MSZP), shaped like corn seeds, were tested against non-pelleted A. syriaca seeds in several indoor and outdoor pot experiments. Molding into MSZP did not affect percent emergence or time to emergence from a 2-cm planting depth. Intraspecific competition among seedlings that emerged from an MSZP did not differ from competition among seedlings that emerged from a cluster of non-pelleted seeds. These findings demonstrate the potential of MSZP technology as a precise and efficient method for increasing agroecosystem biodiversity.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"71 1","pages":"160 - 171"},"PeriodicalIF":2.5,"publicationDate":"2023-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43694444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Vipergrass [Dinebra retroflexa (Vahl) Panzer] is an annual weed of the Poaceae family distributed in several parts of Australia, Asia, and Europe. Very limited information is available on its germination response to different environmental conditions. Knowledge of its seed ecology and biology could help in formulating better weed management decisions. Experiments were conducted to study the effect of alternating temperatures, light conditions, salt stress, water stress, seed burial depths, and wheat residue amounts on the germination or emergence of D. retroflexa. Also, different pre- and postemergence herbicides were evaluated to control D. retroflexa. The highest germination (98%) was recorded at 30/20 C followed by 35/25 C (95%). Light was required for the germination of D. retroflexa. Germination decreased with an increase in sodium chloride (NaCl) concentrations. Even at 80 mM NaCl, 81% of seeds germinated, indicating D. retroflexa's high salt tolerance. Seed germination gradually decreased with an increase in water stress, and no germination was recorded at –0.8 MPa osmotic potential. The emergence of D. retroflexa decreased with an increase in seed burial depths. The highest germination (83%) was recorded for surface-sown seeds, and emergence was reduced to 0 at a burial depth of 2 cm. Seedling emergence decreased from 82% to 2% when the crop residue load was increased from 0 to 800 kg ha–1. Applications of preemergence herbicides (at field rates), such as diuron, isoxaflutole, pendimethalin, pyroxasulfone, S-metolachlor, terbuthylazine, and triallate, and postemergence herbicides, such as clethodim, haloxyfop-methyl, glufosinate, glyphosate, imazamox plus imazapyr (a commercial mixture), and paraquat, resulted in complete control (100%) of D. retroflexa. Knowledge gained from this study will help us to understand the potential spread of D. retroflexa to other areas and to formulate integrated weed management strategies for its effective control.
摘要Vipergrass[Dinebra retroflexa（Vahl）Panzer]是一种一年生Poaceae科杂草，分布在澳大利亚、亚洲和欧洲的几个地区。关于其对不同环境条件的发芽反应的信息非常有限。了解其种子生态学和生物学可以帮助制定更好的杂草管理决策。试验研究了交替温度、光照条件、盐胁迫、水分胁迫、种子埋深和小麦残留量对反曲弯孢的发芽或出苗的影响。此外，还对不同的羽化前和羽化后除草剂进行了评价，以控制反曲线虫。最高发芽率（98%）记录在30/20℃，其次是35/25℃（95%）。光照是反曲D.retroflexa发芽所必需的。随着氯化钠浓度的增加，发芽率降低。即使在80 mM NaCl下，81%的种子也发芽了，这表明D.retroflexa具有很高的耐盐性。种子发芽率随着水分胁迫的增加而逐渐降低，在–0.8 MPa渗透势下没有发芽记录。随着种子埋深的增加，后弯D.flexa的出现减少。地表播种种子的发芽率最高（83%），埋深2厘米时出苗率降至0。当作物残留量从0增加到800 kg ha–1时，幼苗出苗率从82%降至2%。使用孕前除草剂（按田间速率），如敌草隆、异恶唑、二甲戊灵、吡喃砜、S-甲草胺、terbuthylazine和triallate，以及出苗后除草剂，如氯托丁、卤代磺酰甲基、草膦、草甘膦、伊扎莫加伊扎吡（一种商业混合物）和百草枯，可完全控制（100%）反曲弯线虫。从这项研究中获得的知识将有助于我们了解D.retroflexa向其他地区的潜在传播，并制定有效控制其的综合杂草管理策略。
{"title":"Germination Responses of Vipergrass (Dinebra retroflexa) to Environmental Factors and Herbicide Options for Its Control","authors":"Sachin Dhanda, K. Sharma, B. Chauhan","doi":"10.1017/wsc.2023.3","DOIUrl":"https://doi.org/10.1017/wsc.2023.3","url":null,"abstract":"Abstract Vipergrass [Dinebra retroflexa (Vahl) Panzer] is an annual weed of the Poaceae family distributed in several parts of Australia, Asia, and Europe. Very limited information is available on its germination response to different environmental conditions. Knowledge of its seed ecology and biology could help in formulating better weed management decisions. Experiments were conducted to study the effect of alternating temperatures, light conditions, salt stress, water stress, seed burial depths, and wheat residue amounts on the germination or emergence of D. retroflexa. Also, different pre- and postemergence herbicides were evaluated to control D. retroflexa. The highest germination (98%) was recorded at 30/20 C followed by 35/25 C (95%). Light was required for the germination of D. retroflexa. Germination decreased with an increase in sodium chloride (NaCl) concentrations. Even at 80 mM NaCl, 81% of seeds germinated, indicating D. retroflexa's high salt tolerance. Seed germination gradually decreased with an increase in water stress, and no germination was recorded at –0.8 MPa osmotic potential. The emergence of D. retroflexa decreased with an increase in seed burial depths. The highest germination (83%) was recorded for surface-sown seeds, and emergence was reduced to 0 at a burial depth of 2 cm. Seedling emergence decreased from 82% to 2% when the crop residue load was increased from 0 to 800 kg ha–1. Applications of preemergence herbicides (at field rates), such as diuron, isoxaflutole, pendimethalin, pyroxasulfone, S-metolachlor, terbuthylazine, and triallate, and postemergence herbicides, such as clethodim, haloxyfop-methyl, glufosinate, glyphosate, imazamox plus imazapyr (a commercial mixture), and paraquat, resulted in complete control (100%) of D. retroflexa. Knowledge gained from this study will help us to understand the potential spread of D. retroflexa to other areas and to formulate integrated weed management strategies for its effective control.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"71 1","pages":"124 - 132"},"PeriodicalIF":2.5,"publicationDate":"2023-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42931286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Justin D. L. Fisher, Christy L. Sprague, Eric L. Patterson, John A. Schramski
Abstract Horseweed [Conyza canadensis (L.) Cronquist] grows in one of two distinct growth phenotypes, “rosette” and “upright” growth types, and they have recently been observed co-occurring in Michigan fields. Previous research found that upright plants from two glyphosate-resistant populations were 3- and 4-fold less sensitive to glyphosate than their rosette siblings. Further experiments were conducted to investigate whether differential glyphosate sensitivity of the growth types was due to glyphosate retention, absorption, or translocation. The total amount of glyphosate retained on the C. canadensis leaf surface was similar for both growth types; however, on a per-weight and per-area bases, the upright growth type retained 21% and 18% less glyphosate, respectively. Glyphosate absorption was up to 85% at 168 h after treatment (HAT), and was not different between the rosette and upright growth types or between the susceptible (S) and resistant (R) biotypes. Additionally, there was no difference in translocation between the two growth types within each biotype at any time point. Interestingly, at 168 HAT, [14C]glyphosate translocation was higher in the S rosette compared with the two growth types from the R biotype; however, the S upright type was similar to both R growth types. Thus, glyphosate resistance in the R biotype may be due to an alternative mechanism rather than impaired translocation, which has been cited as the primary mechanism of glyphosate resistance in C. canadensis. These results suggest that reduced glyphosate retention on a per-weight and per-area bases of the upright growth type may contribute to increased glyphosate tolerance due to a diluted concentration of glyphosate in the plant. However, another factor is likely related to the mechanism of resistance within the R biotype, which is contributing to a 3-fold difference in glyphosate sensitivity between the two growth types, such as alterations in EPSPS gene expression or changes in undescribed metabolism genes.
{"title":"Investigations into Differential Glyphosate Sensitivity between Two Horseweed (Conyza Canadensis) Growth Types","authors":"Justin D. L. Fisher, Christy L. Sprague, Eric L. Patterson, John A. Schramski","doi":"10.1017/wsc.2022.69","DOIUrl":"https://doi.org/10.1017/wsc.2022.69","url":null,"abstract":"Abstract Horseweed [Conyza canadensis (L.) Cronquist] grows in one of two distinct growth phenotypes, “rosette” and “upright” growth types, and they have recently been observed co-occurring in Michigan fields. Previous research found that upright plants from two glyphosate-resistant populations were 3- and 4-fold less sensitive to glyphosate than their rosette siblings. Further experiments were conducted to investigate whether differential glyphosate sensitivity of the growth types was due to glyphosate retention, absorption, or translocation. The total amount of glyphosate retained on the C. canadensis leaf surface was similar for both growth types; however, on a per-weight and per-area bases, the upright growth type retained 21% and 18% less glyphosate, respectively. Glyphosate absorption was up to 85% at 168 h after treatment (HAT), and was not different between the rosette and upright growth types or between the susceptible (S) and resistant (R) biotypes. Additionally, there was no difference in translocation between the two growth types within each biotype at any time point. Interestingly, at 168 HAT, [14C]glyphosate translocation was higher in the S rosette compared with the two growth types from the R biotype; however, the S upright type was similar to both R growth types. Thus, glyphosate resistance in the R biotype may be due to an alternative mechanism rather than impaired translocation, which has been cited as the primary mechanism of glyphosate resistance in C. canadensis. These results suggest that reduced glyphosate retention on a per-weight and per-area bases of the upright growth type may contribute to increased glyphosate tolerance due to a diluted concentration of glyphosate in the plant. However, another factor is likely related to the mechanism of resistance within the R biotype, which is contributing to a 3-fold difference in glyphosate sensitivity between the two growth types, such as alterations in EPSPS gene expression or changes in undescribed metabolism genes.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"71 1","pages":"22 - 28"},"PeriodicalIF":2.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45429669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sandra R. Ethridge, Saket Chandra, W. Everman, D. Jordan, Anna M. Locke, M. Owen, R. León
Abstract Competition between genotypes within a plant population can result in the displacement of the least competitive by more competitive genotypes. Although evolutionary processes in plants may occur over thousands and millions of years, it has been suggested that changes in key fitness traits could occur in as little as decades, with herbicide resistance being a common example. However, the rapid evolution of complex traits has not been proven in weeds. We hypothesized that changes in weed growth and competitive ability can occur in just a few years because of selection in agroecosystems. Seed of multiple generations of a single natural population of the grassy weed giant foxtail (Setaria faberi Herrm.) were collected during 34 yr (i.e., 1983 to 2017). Using a “resurrection” approach, we characterized life-history traits of the different year-lines under noncompetitive and competitive conditions. Replacement-series experiments comparing the growth of the oldest year-line (1983) versus newer year-lines (1991, 1996, 1998, 2009, and 2017) showed that plant competitive ability decreased and then increased progressively in accordance with oscillating selection. The adaptations in competitive ability were reflected in dynamic changes in leaf area and biomass when plants were in competition. The onset of increased competitive ability coincided with the introduction of herbicide-resistant crops in the landscape in 1996. We also conducted a genome-wide association study and identified four loci that were associated with increased competitive ability over time, confirming that this trait changed in response to directional selection. Putative transcription factors and cell wall–associated enzymes were linked to those loci. This is the first study providing direct in situ evidence of rapid directional evolution of competitive ability in a plant species. The results suggest that agricultural systems can exert enough pressure to cause evolutionary adaptations of complex life-history traits, potentially increasing weediness and invasiveness.
{"title":"Rapid Evolution of Competitive Ability in Giant Foxtail (Setaria Faberi) Over 34 Years","authors":"Sandra R. Ethridge, Saket Chandra, W. Everman, D. Jordan, Anna M. Locke, M. Owen, R. León","doi":"10.1017/wsc.2023.1","DOIUrl":"https://doi.org/10.1017/wsc.2023.1","url":null,"abstract":"Abstract Competition between genotypes within a plant population can result in the displacement of the least competitive by more competitive genotypes. Although evolutionary processes in plants may occur over thousands and millions of years, it has been suggested that changes in key fitness traits could occur in as little as decades, with herbicide resistance being a common example. However, the rapid evolution of complex traits has not been proven in weeds. We hypothesized that changes in weed growth and competitive ability can occur in just a few years because of selection in agroecosystems. Seed of multiple generations of a single natural population of the grassy weed giant foxtail (Setaria faberi Herrm.) were collected during 34 yr (i.e., 1983 to 2017). Using a “resurrection” approach, we characterized life-history traits of the different year-lines under noncompetitive and competitive conditions. Replacement-series experiments comparing the growth of the oldest year-line (1983) versus newer year-lines (1991, 1996, 1998, 2009, and 2017) showed that plant competitive ability decreased and then increased progressively in accordance with oscillating selection. The adaptations in competitive ability were reflected in dynamic changes in leaf area and biomass when plants were in competition. The onset of increased competitive ability coincided with the introduction of herbicide-resistant crops in the landscape in 1996. We also conducted a genome-wide association study and identified four loci that were associated with increased competitive ability over time, confirming that this trait changed in response to directional selection. Putative transcription factors and cell wall–associated enzymes were linked to those loci. This is the first study providing direct in situ evidence of rapid directional evolution of competitive ability in a plant species. The results suggest that agricultural systems can exert enough pressure to cause evolutionary adaptations of complex life-history traits, potentially increasing weediness and invasiveness.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"71 1","pages":"59 - 68"},"PeriodicalIF":2.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43862997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Geide A. Figueiredo, R. Busi, Danica E. Goggin, Aimone Porri, H. Beckie
Abstract Rigid ryegrass (Lolium rigidum Gaudin) is the most problematic weed in Australia, with evolved resistance to multiple herbicide sites of action. Selection pressure by cinmethylin (Group 30, a fatty-acid thioesterase inhibitor) has been limited, because few populations have been exposed to the herbicide since its introduction in 2019. In this study, we examined the sensitivity of L. rigidum populations to this new herbicide. From a screening of almost 500 field populations in 2020, 28 potentially resistant populations were further investigated in a dose–response experiment. Seedlings from five populations surviving treatments of 250 or 375 g ai ha–1 cinmethylin were grown to maturity and seeds were harvested. The level of resistance found among the five putative-resistant parental populations of L. rigidum was negligible. In one population, one round of selection with cinmethylin resulted in a 2-fold increase in the lethal dose causing 50% mortality in the progeny population, although this dose was still only one-sixth of the recommended field rate of cinmethylin. Having a unique site of action, cinmethylin is a viable preemergence herbicide option to control existing multiple-resistance populations of L. rigidum. Comprehensive field monitoring and recurrent selection studies under controlled environmental conditions are needed to better ascertain the risk of L. rigidum evolving a high level of resistance to cinmethylin, although current data suggest that this risk is relatively low.
{"title":"Sensitivity of Herbicide-Resistant Rigid Ryegrass (Lolium rigidum) Populations to Cinmethylin, a New Herbicide Site of Action","authors":"Geide A. Figueiredo, R. Busi, Danica E. Goggin, Aimone Porri, H. Beckie","doi":"10.1017/wsc.2023.2","DOIUrl":"https://doi.org/10.1017/wsc.2023.2","url":null,"abstract":"Abstract Rigid ryegrass (Lolium rigidum Gaudin) is the most problematic weed in Australia, with evolved resistance to multiple herbicide sites of action. Selection pressure by cinmethylin (Group 30, a fatty-acid thioesterase inhibitor) has been limited, because few populations have been exposed to the herbicide since its introduction in 2019. In this study, we examined the sensitivity of L. rigidum populations to this new herbicide. From a screening of almost 500 field populations in 2020, 28 potentially resistant populations were further investigated in a dose–response experiment. Seedlings from five populations surviving treatments of 250 or 375 g ai ha–1 cinmethylin were grown to maturity and seeds were harvested. The level of resistance found among the five putative-resistant parental populations of L. rigidum was negligible. In one population, one round of selection with cinmethylin resulted in a 2-fold increase in the lethal dose causing 50% mortality in the progeny population, although this dose was still only one-sixth of the recommended field rate of cinmethylin. Having a unique site of action, cinmethylin is a viable preemergence herbicide option to control existing multiple-resistance populations of L. rigidum. Comprehensive field monitoring and recurrent selection studies under controlled environmental conditions are needed to better ascertain the risk of L. rigidum evolving a high level of resistance to cinmethylin, although current data suggest that this risk is relatively low.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"71 1","pages":"4 - 10"},"PeriodicalIF":2.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47286742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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