This study investigated replicating six generations of glasshouse-based flowering date selection in wild radish (Raphanus raphanistrum L.) using an adaptation of the population model SOMER (Spatial Orientated Modelling of Evolutionary Resistance). This individual-based model was chosen because it could be altered to contain varying numbers of genes, along with varying levels of environmental influence on the phenotype (namely the heritability). Accurate replication of six generations of genetic change that had occurred in a previous glasshouse-based selection was achieved, without intermediate adjustments. This study found that multiple copies of just two genes were required to reproduce the polygenic flowering time adaptations demonstrated in that previous research. The model included major effect type M1 genes, with linkage and crossing over, and minor effect type M2 genes undergoing independent assortment. Within the model, transmissibility (heritability of each gene type) was parameterized at 0.60 for the M1 genes and 0.45 for the M2 genes. The serviceable parameterization of the genetics of flowering in R. raphanistrum within a population model means that simulated examinations of the effects of external weed control on flowering time adaptations are now more feasible. An accurate and simplified Mendelian-based model replicating the adaptive shifts of flowering time that is controlled by a complex array of genes is useful in predicting life-cycle adaptations to evade weed control measures such as harvest weed seed control, which apply intense adaptive selections on traits that affect seed retention, including flowering time.
{"title":"Adaptations in wild radish (Raphanus raphanistrum) flowering time, Part 1: Individual-based modeling of a polygenic trait","authors":"G. J. Somerville, Mike Ashworth, H. Beckie","doi":"10.1017/wsc.2023.76","DOIUrl":"https://doi.org/10.1017/wsc.2023.76","url":null,"abstract":"\u0000 This study investigated replicating six generations of glasshouse-based flowering date selection in wild radish (Raphanus raphanistrum L.) using an adaptation of the population model SOMER (Spatial Orientated Modelling of Evolutionary Resistance). This individual-based model was chosen because it could be altered to contain varying numbers of genes, along with varying levels of environmental influence on the phenotype (namely the heritability).\u0000 Accurate replication of six generations of genetic change that had occurred in a previous glasshouse-based selection was achieved, without intermediate adjustments. This study found that multiple copies of just two genes were required to reproduce the polygenic flowering time adaptations demonstrated in that previous research. The model included major effect type M1 genes, with linkage and crossing over, and minor effect type M2 genes undergoing independent assortment. Within the model, transmissibility (heritability of each gene type) was parameterized at 0.60 for the M1 genes and 0.45 for the M2 genes. The serviceable parameterization of the genetics of flowering in R. raphanistrum within a population model means that simulated examinations of the effects of external weed control on flowering time adaptations are now more feasible. An accurate and simplified Mendelian-based model replicating the adaptive shifts of flowering time that is controlled by a complex array of genes is useful in predicting life-cycle adaptations to evade weed control measures such as harvest weed seed control, which apply intense adaptive selections on traits that affect seed retention, including flowering time.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"56 25","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139442108","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}
O. Daramola, J. Iboyi, Gregory E. MacDonald, Ramdas G. Kanissery, Barry L. Tillman, Hardeep Singh, P. Devkota
Herbicides are the primary tool for controlling weeds in peanut and are crucial to sustainable peanut (Arachis hypogaea L.) production in the United States (US). The literature on chemical weed management in peanut in the past 53 years (1970 to 2022) in the US was systematically reviewed to highlight the strength and weaknesses of different herbicides and identify current research gaps in chemical weed management. Residual weed control in peanut is achieved mainly with dimethenamid-P, ethalfluralin, flumioxazin, pendimethalin, and S-metolachlor. More recently, the use of the PPO-inhibitor, and ALS-inhibitors such as diclosulam for residual weed control in peanut has increased considerably. Postemergence broadleaf weed control in peanut is achieved mainly with acifluorfen, bentazon, diclosulam, imazapic, lactofen, paraquat, and 2,4−DB, while the graminicides clethodim and sethoxydim are the major postemergence grass weed control herbicides in peanut. Although several herbicides are available for weed control in peanut, no single herbicide can provide season-long weed control due to limited application timing, lack of extended residual activity, variability in weed control spectrum, and rotational restrictions. Therefore, effective weed management in peanut often requires herbicide mixtures and/or sequential application of pre-plant incorporated, preemergence, and/or postemergence herbicides. However, the available literature showed a substantive range in herbicide efficacy due to variations in environmental conditions and flushes of weed germination across years and locations. Despite the relatively high efficacy of herbicides, the selection of herbicide-resistant weeds is another area of increasing concern. Future research should focus on developing new strategies for preventing or delaying the development of resistance and improving herbicide efficacy within the context of climate change and emerging constraints such as water shortages, temperature rise and increasing CO2 concentration.
{"title":"A Systematic Review of Chemical Weed Management in Peanut (Arachis hypogea) in the United States: Challenges and Opportunities","authors":"O. Daramola, J. Iboyi, Gregory E. MacDonald, Ramdas G. Kanissery, Barry L. Tillman, Hardeep Singh, P. Devkota","doi":"10.1017/wsc.2023.71","DOIUrl":"https://doi.org/10.1017/wsc.2023.71","url":null,"abstract":"Herbicides are the primary tool for controlling weeds in peanut and are crucial to sustainable peanut (Arachis hypogaea L.) production in the United States (US). The literature on chemical weed management in peanut in the past 53 years (1970 to 2022) in the US was systematically reviewed to highlight the strength and weaknesses of different herbicides and identify current research gaps in chemical weed management. Residual weed control in peanut is achieved mainly with dimethenamid-P, ethalfluralin, flumioxazin, pendimethalin, and S-metolachlor. More recently, the use of the PPO-inhibitor, and ALS-inhibitors such as diclosulam for residual weed control in peanut has increased considerably. Postemergence broadleaf weed control in peanut is achieved mainly with acifluorfen, bentazon, diclosulam, imazapic, lactofen, paraquat, and 2,4−DB, while the graminicides clethodim and sethoxydim are the major postemergence grass weed control herbicides in peanut. Although several herbicides are available for weed control in peanut, no single herbicide can provide season-long weed control due to limited application timing, lack of extended residual activity, variability in weed control spectrum, and rotational restrictions. Therefore, effective weed management in peanut often requires herbicide mixtures and/or sequential application of pre-plant incorporated, preemergence, and/or postemergence herbicides. However, the available literature showed a substantive range in herbicide efficacy due to variations in environmental conditions and flushes of weed germination across years and locations. Despite the relatively high efficacy of herbicides, the selection of herbicide-resistant weeds is another area of increasing concern. Future research should focus on developing new strategies for preventing or delaying the development of resistance and improving herbicide efficacy within the context of climate change and emerging constraints such as water shortages, temperature rise and increasing CO2 concentration.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"23 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139240686","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}
Estéfani Sulzbach, G. Turra, L. Cutti, Leonardo Vicente Ellert Kroth, P. Tranel, A. Merotto, Catarine Markus
The presence of glyphosate-resistant smooth pigweed (Amaranthus hybridus L.) biotypes has increased in southern Brazil in the last years, presenting the triple amino acid substitution TAP-IVS in the 5-enol-pyruvylshikimate-3-phosphate synthase (EPSPS), as previously found in Argentina. Some of these biotypes have morphological characteristics of smooth pigweed and redroot amaranth (Amaranthus retroflexus L.). The present study aimed to identify, through molecular markers, the herbicide-resistant species of Amaranthus from Brazil that have the TAP-IVS substitution and to analyze the occurrence of pollen-mediated gene flow (PMGF) as the source of TAP-IVS substitution in these biotypes. Six biotypes were evaluated by the internal transcribed spacer (ITS) sequences, of which two (AMACHY-S and CAMAQ-R) were molecularly classified as A. hybridus, and four (AMACRET-S, AMACVI-S, ARRGR-R, and SAOJER-R) were unclassified. Interestingly, all the glyphosate-resistant biotypes (ARRGR-R, SAOJER-R, and CAMAQ-R) had the TAP-IVS substitution, and an increase in EPSPS relative copy number; however, only CAMAQ-R was confirmed as A. hybridus. Although the biotypes ARRGR-R and SAOJER-R are closely related to A. hybridus and green pigweed (Amaranthus powellii S. Watson), their species identity could not be resolved. The biotype SAOJER-R also was resistant to ALS-inhibiting herbicides due to a tryptophan to leucine substitution at position 574 in acetolactate synthase (ALS). The evaluation of 119,746 seedlings in an intraspecific hybridization study of A. hybridus indicated an outcrossing frequency of 0.09%. In contrast, an absence of interspecific hybridization (A. hybridus × unclassified biotype – AMACVI-S) was found after screening 111,429 offspring. Unclassified biotypes might be derived from one or more ancient hybridization events and subsequently evolved the triple mutation independently. Alternatively, such biotypes could have evolved from recent hybridization events, which occur at a frequency below the level of detection in our study.
{"title":"Smooth pigweed (Amaranthus hybridus) and unresolved Amaranthus spp. from Brazil resistant to glyphosate exhibit the EPSPS TAP-IVS substitution","authors":"Estéfani Sulzbach, G. Turra, L. Cutti, Leonardo Vicente Ellert Kroth, P. Tranel, A. Merotto, Catarine Markus","doi":"10.1017/wsc.2023.70","DOIUrl":"https://doi.org/10.1017/wsc.2023.70","url":null,"abstract":"The presence of glyphosate-resistant smooth pigweed (Amaranthus hybridus L.) biotypes has increased in southern Brazil in the last years, presenting the triple amino acid substitution TAP-IVS in the 5-enol-pyruvylshikimate-3-phosphate synthase (EPSPS), as previously found in Argentina. Some of these biotypes have morphological characteristics of smooth pigweed and redroot amaranth (Amaranthus retroflexus L.). The present study aimed to identify, through molecular markers, the herbicide-resistant species of Amaranthus from Brazil that have the TAP-IVS substitution and to analyze the occurrence of pollen-mediated gene flow (PMGF) as the source of TAP-IVS substitution in these biotypes. Six biotypes were evaluated by the internal transcribed spacer (ITS) sequences, of which two (AMACHY-S and CAMAQ-R) were molecularly classified as A. hybridus, and four (AMACRET-S, AMACVI-S, ARRGR-R, and SAOJER-R) were unclassified. Interestingly, all the glyphosate-resistant biotypes (ARRGR-R, SAOJER-R, and CAMAQ-R) had the TAP-IVS substitution, and an increase in EPSPS relative copy number; however, only CAMAQ-R was confirmed as A. hybridus. Although the biotypes ARRGR-R and SAOJER-R are closely related to A. hybridus and green pigweed (Amaranthus powellii S. Watson), their species identity could not be resolved. The biotype SAOJER-R also was resistant to ALS-inhibiting herbicides due to a tryptophan to leucine substitution at position 574 in acetolactate synthase (ALS). The evaluation of 119,746 seedlings in an intraspecific hybridization study of A. hybridus indicated an outcrossing frequency of 0.09%. In contrast, an absence of interspecific hybridization (A. hybridus × unclassified biotype – AMACVI-S) was found after screening 111,429 offspring. Unclassified biotypes might be derived from one or more ancient hybridization events and subsequently evolved the triple mutation independently. Alternatively, such biotypes could have evolved from recent hybridization events, which occur at a frequency below the level of detection in our study.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"35 36","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139240097","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}
Jasmine Mausbach, S. Irmak, M. Kukal, Kelsey Karnik, D. Sarangi, Amit J. Jhala
Palmer amaranth (Amaranthus palmeri S. Watson) is a major biotic constraint in agronomic cropping systems in the United States. While crop-weed competition models offer a beneficial tool for understanding and predicting crop yield losses, within these models, certain weed biological characteristics and their response to the environment are unknown. This limits understanding of weed growth in competition with crops under different irrigation methods and how competition for soil moisture affects crop growth parameters. This research measured the effect of center-pivot irrigation (CPI) and subsurface drip irrigation (SDI) on the actual evapotranspiration (ET a ) of A. palmeri grown in maize (Zea mays L.), soybean [Glycine max (L.) Merr.], and fallow subplots. Twelve A. palmeri plants were alternately transplanted one meter apart in the middle two rows of maize, soybean, and fallow subplots under CPI and SDI in 2019 and 2020 in southcentral Nebraska. Maize, soybean, and fallow subplots without A. palmeri were included for comparison. Soil moisture sensors were installed at 0-0.30, 0.30-0.60, and 0.60-0.90-m soil depths next to or between three A. palmeri and crop plants in each subplot. Soil moisture data were recorded hourly from the time of A. palmeri transplanting to crop harvest. The results indicate differences in A. palmeri ET a between time of season (early-, mid-, late-season) and crop type across 2019 and 2020. Although irrigation type did not affect subplot data, the presence of A. palmeri had an impact on subplot ET a across both years, which can be attributed to the variable relationship between volumetric soil water content (VWC) and ET a throughout the growing season due to advancing phenological stages and management practices. This study provides important and firstly established baseline data and information about A. palmeri evapotranspiration and its relation to morphological features for future use in mechanistic crop-weed competition models.
帕尔默苋（Amaranthus palmeri S. Watson）是美国农艺种植系统中的主要生物制约因素。虽然作物-杂草竞争模型为了解和预测作物产量损失提供了有利工具，但在这些模型中，某些杂草的生物特征及其对环境的反应尚不清楚。这限制了人们对不同灌溉方法下杂草生长与作物竞争以及土壤水分竞争如何影响作物生长参数的了解。本研究测量了中心喷灌（CPI）和地下滴灌（SDI）对生长在玉米（Zea mays L.）、大豆（Glycine max (L.) Merr.）和休耕地块中的棕榈蓟实际蒸散量（ET a）的影响。2019 年和 2020 年，在内布拉斯加州中南部，在 CPI 和 SDI 条件下，在玉米、大豆和休耕地子块的中间两行，每隔一米交替移栽 12 株 A. palmeri。玉米、大豆和休耕地中没有种植棕榈蓟马的地块也被纳入其中进行比较。土壤水分传感器分别安装在 0-0.30、0.30-0.60 和 0.60-0.90 米的土壤深度，紧邻每块子块中的三株棕榈蓟和作物植株或它们之间。从棕榈蓟移栽到作物收获，每小时记录一次土壤水分数据。结果表明，在 2019 年和 2020 年期间，不同季节（早季、中季、晚季）和作物类型的棕榈叶蒸腾速率存在差异。虽然灌溉类型不影响子地块的数据，但棕榈蓟的存在对这两年子地块的蒸散发有影响，这可能是由于物候期和管理措施的推进导致整个生长季土壤容积含水量（VWC）和蒸散发之间的关系变化所致。这项研究首次提供了有关棕榈蓟蒸腾作用及其与形态特征关系的重要基准数据和信息，可用于未来的作物-杂草竞争机理模型。
{"title":"Evapotranspiration of Palmer amaranth (Amaranthus palmeri) in maize, soybean, and fallow under subsurface drip and center-pivot irrigation systems","authors":"Jasmine Mausbach, S. Irmak, M. Kukal, Kelsey Karnik, D. Sarangi, Amit J. Jhala","doi":"10.1017/wsc.2023.57","DOIUrl":"https://doi.org/10.1017/wsc.2023.57","url":null,"abstract":"Palmer amaranth (Amaranthus palmeri S. Watson) is a major biotic constraint in agronomic cropping systems in the United States. While crop-weed competition models offer a beneficial tool for understanding and predicting crop yield losses, within these models, certain weed biological characteristics and their response to the environment are unknown. This limits understanding of weed growth in competition with crops under different irrigation methods and how competition for soil moisture affects crop growth parameters. This research measured the effect of center-pivot irrigation (CPI) and subsurface drip irrigation (SDI) on the actual evapotranspiration (ET a ) of A. palmeri grown in maize (Zea mays L.), soybean [Glycine max (L.) Merr.], and fallow subplots. Twelve A. palmeri plants were alternately transplanted one meter apart in the middle two rows of maize, soybean, and fallow subplots under CPI and SDI in 2019 and 2020 in southcentral Nebraska. Maize, soybean, and fallow subplots without A. palmeri were included for comparison. Soil moisture sensors were installed at 0-0.30, 0.30-0.60, and 0.60-0.90-m soil depths next to or between three A. palmeri and crop plants in each subplot. Soil moisture data were recorded hourly from the time of A. palmeri transplanting to crop harvest. The results indicate differences in A. palmeri ET a between time of season (early-, mid-, late-season) and crop type across 2019 and 2020. Although irrigation type did not affect subplot data, the presence of A. palmeri had an impact on subplot ET a across both years, which can be attributed to the variable relationship between volumetric soil water content (VWC) and ET a throughout the growing season due to advancing phenological stages and management practices. This study provides important and firstly established baseline data and information about A. palmeri evapotranspiration and its relation to morphological features for future use in mechanistic crop-weed competition models.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"24 2","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139266409","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}
F. H. Oreja, N. G. Genna, Jose L. Gonzalez-Andujar, S. Wuest, Judit Barroso
Russian thistle (Salsola tragus L.) is among the most troublesome weeds in cropland and ruderal semiarid areas of the Pacific Northwest (PNW). Predicting S. tragus emergence timing plays a critical role in scheduling weed management measures. The objective of this research was to develop and validate a predictive model of the seedling emergence pattern of S. tragus under field conditions in the PNW to increase the efficacy of control measures targeting this species. The relationship between cumulative seedling emergence and cumulative hydrothermal time under field conditions was modeled using the Weibull function. This model is the first to use hydrothermal time units (HTT) to predict S. tragus emergence and showed a very good fit to the experimental data. According to this model, seedling emergence starts at 5 HTT and 50% and 90% emergence is completed at 56 HTT and 177 HTT, respectively. For model validation, independent field experiments were carried out. Cumulative seedling emergence was accurately predicted by the model, supporting the idea that this model is robust enough to be used as a predictive tool for S. tragus seedling emergence. Our model can serve as the basis for the development of decision support systems, helping farmers make the best decisions to control S. tragus populations in no-till fallow and spring wheat systems.
{"title":"A hydrothermal model to predict Russian thistle (Salsola tragus) seedling emergence in the dryland of the Pacific Northwest (USA)","authors":"F. H. Oreja, N. G. Genna, Jose L. Gonzalez-Andujar, S. Wuest, Judit Barroso","doi":"10.1017/wsc.2023.67","DOIUrl":"https://doi.org/10.1017/wsc.2023.67","url":null,"abstract":"Russian thistle (Salsola tragus L.) is among the most troublesome weeds in cropland and ruderal semiarid areas of the Pacific Northwest (PNW). Predicting S. tragus emergence timing plays a critical role in scheduling weed management measures. The objective of this research was to develop and validate a predictive model of the seedling emergence pattern of S. tragus under field conditions in the PNW to increase the efficacy of control measures targeting this species. The relationship between cumulative seedling emergence and cumulative hydrothermal time under field conditions was modeled using the Weibull function. This model is the first to use hydrothermal time units (HTT) to predict S. tragus emergence and showed a very good fit to the experimental data. According to this model, seedling emergence starts at 5 HTT and 50% and 90% emergence is completed at 56 HTT and 177 HTT, respectively. For model validation, independent field experiments were carried out. Cumulative seedling emergence was accurately predicted by the model, supporting the idea that this model is robust enough to be used as a predictive tool for S. tragus seedling emergence. Our model can serve as the basis for the development of decision support systems, helping farmers make the best decisions to control S. tragus populations in no-till fallow and spring wheat systems.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"32 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139263158","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. M. Craft, Navdeep Godara, C. Gonçalves, S. Askew
Turfgrass managers are concerned about zoysiagrass (Zoysia japonica Steud.) injury from nonselective herbicide treatment during winter dormancy. Research was conducted to assess factors affecting spray penetration into semidormant ‘Meyer’ zoysiagrass canopies and to evaluate absorption and translocation of 14C-glyphosate and 14C-glufosinate into green leaves and subtending stolons. Absorption of 14C-glyphosate and 14C-glufosinate was up to four times greater when exposed to stolons than leaves. Zoysiagrass leaves treated with 14C-glufosinate had more rapid 14C absorption than those treated with 14C-glyphosate. More 14C translocated out of the treated area following 14C-glyphosate treatment compared to 14C-glufosinate, and moved more readily from stolon to leaves than from leaves to stolon. When extended range, flat fan spray tips (XR) were positioned 61-cm above zoysiagrass, 73% and 11% of recovered colorant was extracted from dormant vegetation in the upper and lower canopy levels. Turbo TeeJet spray tips (TTI) deposited less droplets into the upper canopy and more droplets into the middle and lower canopy regardless of position above the turf surface. Increasing pressure from 103 to 414 kPa increased droplet velocities from XR and TTI nozzles and decreased droplet diameters of XR nozzles. Droplet diameters were also substantially increased when using TTI nozzles compared to XR nozzles. Droplet diameter and associated mass were more determinant of turfgrass canopy penetration than droplet velocity. At 60 L ha-1 of carrier volume, 23% of colorant reached the lower canopy level, and this quantity increased by 2.3% per additional 100 L ha-1. When carrier volume was reduced from 584 to 60 L ha-1, 48% less colorant was delivered to the lower canopy level. Given that subcanopy stolons are always present and absorb more glyphosate and glufosinate than leaves, practices such as avoiding induction-type nozzles, raising spray height, and reducing spray volume can reduce herbicide delivery and potential injury to semidormant zoysiagrass.
{"title":"Factors influencing subcanopy leaf and stolon exposure and associated absorption and translocation of herbicides in semidormant zoysiagrass","authors":"J. M. Craft, Navdeep Godara, C. Gonçalves, S. Askew","doi":"10.1017/wsc.2023.65","DOIUrl":"https://doi.org/10.1017/wsc.2023.65","url":null,"abstract":"Turfgrass managers are concerned about zoysiagrass (Zoysia japonica Steud.) injury from nonselective herbicide treatment during winter dormancy. Research was conducted to assess factors affecting spray penetration into semidormant ‘Meyer’ zoysiagrass canopies and to evaluate absorption and translocation of 14C-glyphosate and 14C-glufosinate into green leaves and subtending stolons. Absorption of 14C-glyphosate and 14C-glufosinate was up to four times greater when exposed to stolons than leaves. Zoysiagrass leaves treated with 14C-glufosinate had more rapid 14C absorption than those treated with 14C-glyphosate. More 14C translocated out of the treated area following 14C-glyphosate treatment compared to 14C-glufosinate, and moved more readily from stolon to leaves than from leaves to stolon. When extended range, flat fan spray tips (XR) were positioned 61-cm above zoysiagrass, 73% and 11% of recovered colorant was extracted from dormant vegetation in the upper and lower canopy levels. Turbo TeeJet spray tips (TTI) deposited less droplets into the upper canopy and more droplets into the middle and lower canopy regardless of position above the turf surface. Increasing pressure from 103 to 414 kPa increased droplet velocities from XR and TTI nozzles and decreased droplet diameters of XR nozzles. Droplet diameters were also substantially increased when using TTI nozzles compared to XR nozzles. Droplet diameter and associated mass were more determinant of turfgrass canopy penetration than droplet velocity. At 60 L ha-1 of carrier volume, 23% of colorant reached the lower canopy level, and this quantity increased by 2.3% per additional 100 L ha-1. When carrier volume was reduced from 584 to 60 L ha-1, 48% less colorant was delivered to the lower canopy level. Given that subcanopy stolons are always present and absorb more glyphosate and glufosinate than leaves, practices such as avoiding induction-type nozzles, raising spray height, and reducing spray volume can reduce herbicide delivery and potential injury to semidormant zoysiagrass.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"61 3","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139263718","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}
Democrito Rebong, Shannon Henriquez Inoa, Virginia M. Moore, S. C. Reberg‐Horton, Steven Mirsky, J. P. Murphy, Ramon G. Leon
Rapid increase in the hectarage and agricultural systems that use cover cropping for soil conservation and improvement, soil moisture retention, and weed management has highlighted the need to develop formal breeding programs for cover crop species. Cereal rye (Secale cereale L.) is preferred by many growers due to high biomass production and weed suppression potential, which is believed to be partially due to allelopathy. Rye germplasm exhibits large variability in allelopathic activity, which could be used to breed rye with enhanced weed suppression. Here, we provide an overview of rye history and breeding and describe a strategy to develop rye lines with increased allelopathic activity. The discussion focuses on ways to deal with important challenges to achieve this goal including obligate cross pollination and its consequent high segregation levels, and the need to quantify allelopathic activity under field conditions. This review seeks to encourage weed scientists to collaborate with plant breeders and promote the development of cover crop cultivars better suited to reduce weed populations.
{"title":"Breeding allelopathy in cereal rye for weed suppression","authors":"Democrito Rebong, Shannon Henriquez Inoa, Virginia M. Moore, S. C. Reberg‐Horton, Steven Mirsky, J. P. Murphy, Ramon G. Leon","doi":"10.1017/wsc.2023.64","DOIUrl":"https://doi.org/10.1017/wsc.2023.64","url":null,"abstract":"Rapid increase in the hectarage and agricultural systems that use cover cropping for soil conservation and improvement, soil moisture retention, and weed management has highlighted the need to develop formal breeding programs for cover crop species. Cereal rye (Secale cereale L.) is preferred by many growers due to high biomass production and weed suppression potential, which is believed to be partially due to allelopathy. Rye germplasm exhibits large variability in allelopathic activity, which could be used to breed rye with enhanced weed suppression. Here, we provide an overview of rye history and breeding and describe a strategy to develop rye lines with increased allelopathic activity. The discussion focuses on ways to deal with important challenges to achieve this goal including obligate cross pollination and its consequent high segregation levels, and the need to quantify allelopathic activity under field conditions. This review seeks to encourage weed scientists to collaborate with plant breeders and promote the development of cover crop cultivars better suited to reduce weed populations.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"54 8","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139262728","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}
David A. Weisberger, Ramon G. Leon, Chandler E. Gruner, Matthew Levi, N. Gaur, Gaylon Morgan, Nicholas T. Basinger
Palmer amaranth (Amaranthus palmeri S. Watson) is the most problematic weed of cotton cropping systems in the Southeast US. Heavy reliance on herbicides has selected for resistance to multiple herbicide mechanisms of action. Effective management of this weed may require the integration of cultural practices that limit germination, establishment, and growth. Cover crops have been promoted as a cultural practice that targets these processes. We conducted a two-year study in Georgia, USA, to measure the effects of two annual cover crops (cereal rye [Secale cereale L.] and crimson clover (Trifolium incarnatum L.), a perennial living mulch (Durana® white clover, (Trifolium repens L.), and a bare ground control on A. palmeri population dynamics. The study was conducted in the absence of herbicides. Growth stages were integrated into a basic demographic model to evaluate differences in population trajectories. Cereal rye treatments suppressed weed seedling recruitment (seedlings seed-1) by 19.2 and 13 times, and living mulch 12 and 25 times more than the bare ground control. Low recruitment was correlated positively with low light transmission (above canopy PAR/below cover crop PAR) at the soil surface. Low recruitment rates were also negatively correlated with high survival rates. Greater survival rates and reduced adult plant densities resulted in greater biomass (g plant-1) and fecundity (seeds plant-1) in cereal rye and living mulch treatments in both years. The annual rate of population change (seeds seed-1) was equivalent across all treatments in the first year but was greater in the living mulch treatment in the second year. Our results highlight the potential of annual cover crops and living mulches for suppressing A. palmeri seedling recruitment and would be valuable tools as part of an integrated weed management strategy.
{"title":"Demographics of Amaranthus palmeri in annual and perennial cover crops","authors":"David A. Weisberger, Ramon G. Leon, Chandler E. Gruner, Matthew Levi, N. Gaur, Gaylon Morgan, Nicholas T. Basinger","doi":"10.1017/wsc.2023.66","DOIUrl":"https://doi.org/10.1017/wsc.2023.66","url":null,"abstract":"Palmer amaranth (Amaranthus palmeri S. Watson) is the most problematic weed of cotton cropping systems in the Southeast US. Heavy reliance on herbicides has selected for resistance to multiple herbicide mechanisms of action. Effective management of this weed may require the integration of cultural practices that limit germination, establishment, and growth. Cover crops have been promoted as a cultural practice that targets these processes. We conducted a two-year study in Georgia, USA, to measure the effects of two annual cover crops (cereal rye [Secale cereale L.] and crimson clover (Trifolium incarnatum L.), a perennial living mulch (Durana® white clover, (Trifolium repens L.), and a bare ground control on A. palmeri population dynamics. The study was conducted in the absence of herbicides. Growth stages were integrated into a basic demographic model to evaluate differences in population trajectories. Cereal rye treatments suppressed weed seedling recruitment (seedlings seed-1) by 19.2 and 13 times, and living mulch 12 and 25 times more than the bare ground control. Low recruitment was correlated positively with low light transmission (above canopy PAR/below cover crop PAR) at the soil surface. Low recruitment rates were also negatively correlated with high survival rates. Greater survival rates and reduced adult plant densities resulted in greater biomass (g plant-1) and fecundity (seeds plant-1) in cereal rye and living mulch treatments in both years. The annual rate of population change (seeds seed-1) was equivalent across all treatments in the first year but was greater in the living mulch treatment in the second year. Our results highlight the potential of annual cover crops and living mulches for suppressing A. palmeri seedling recruitment and would be valuable tools as part of an integrated weed management strategy.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"38 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139266053","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}
Dylan R. Kerr, Jeanaflor Crystal T. Concepcion, Dean E. Riechers
Abstract Waterhemp [ Amaranthus tuberculatus (Moq.) Sauer] is a dioecious weed that has evolved resistance to very-long-chain fatty acid (VLCFA) elongase-inhibiting herbicides via rapid metabolism. Although detoxification enzyme activities are associated with S -metolachlor resistance in two multiple herbicide-resistant (MHR) A. tuberculatus populations from Illinois, the genetic basis of resistance is unknown. Therefore, our goal was to investigate inheritance of S -metolachlor resistance in the Stanford, Illinois Resistant (SIR) population. Specifically, our research objectives were to: i) generate a uniformly resistant, full-sib near inbred line (DK 3-2 ) via three generations of recurrent selection for resistance using preemergence S -metolachlor, ii) develop A. tuberculatus populations segregating for S -metolachlor resistance via reciprocal single plant (one male × one female) full-sib mating of DK 3-2 and a VLCFA inhibiting herbicide-sensitive population, SEN, iii) quantify S -metolachlor resistance levels in parental lines and their F 1 progenies via greenhouse dose-response analysis, and iv) evaluate inheritance of S -metolachlor resistance in F 2 progenies. Dose-response analysis using 6 to 8 S -metolachlor concentrations (0.015–15.0 μM; varying per population) generated lethal dose (LD) estimates of 50% (LD 50 ) and 90% (LD 90 ) for SIR, SEN, DK 3-2 and F 1 progenies. Lethal dose estimates indicated DK 3-2 has a higher magnitude of S -metolachlor resistance than the SIR population, demonstrating single crosses significantly increased S -metolachlor resistance in DK 3-2 . Levels of S -metolachlor resistance in F 1 populations were intermediate compared to DK 3-2 and SEN. Segregation of S -metolachlor resistance in F 2 families from the paternal-derived lines fit a single-gene model (R:S = 3:1), indicating a single, dominant gene confers S -metolachlor resistance in SIR. However, F 2 segregation results from the maternal-derived lines fit a duplicate recessive epistasis model (R:S = 9:7), indicating a second recessive gene may also modify S -metolachlor resistance in SIR. Results and germplasm derived from this research can assist in identifying the gene(s) conferring resistance to S -metolachlor in A. tuberculatus .
{"title":"Inheritance of resistance to <i>S</i>-metolachlor in a waterhemp (<i>Amaranthus tuberculatus</i>) population from central Illinois","authors":"Dylan R. Kerr, Jeanaflor Crystal T. Concepcion, Dean E. Riechers","doi":"10.1017/wsc.2023.63","DOIUrl":"https://doi.org/10.1017/wsc.2023.63","url":null,"abstract":"Abstract Waterhemp [ Amaranthus tuberculatus (Moq.) Sauer] is a dioecious weed that has evolved resistance to very-long-chain fatty acid (VLCFA) elongase-inhibiting herbicides via rapid metabolism. Although detoxification enzyme activities are associated with S -metolachlor resistance in two multiple herbicide-resistant (MHR) A. tuberculatus populations from Illinois, the genetic basis of resistance is unknown. Therefore, our goal was to investigate inheritance of S -metolachlor resistance in the Stanford, Illinois Resistant (SIR) population. Specifically, our research objectives were to: i) generate a uniformly resistant, full-sib near inbred line (DK 3-2 ) via three generations of recurrent selection for resistance using preemergence S -metolachlor, ii) develop A. tuberculatus populations segregating for S -metolachlor resistance via reciprocal single plant (one male × one female) full-sib mating of DK 3-2 and a VLCFA inhibiting herbicide-sensitive population, SEN, iii) quantify S -metolachlor resistance levels in parental lines and their F 1 progenies via greenhouse dose-response analysis, and iv) evaluate inheritance of S -metolachlor resistance in F 2 progenies. Dose-response analysis using 6 to 8 S -metolachlor concentrations (0.015–15.0 μM; varying per population) generated lethal dose (LD) estimates of 50% (LD 50 ) and 90% (LD 90 ) for SIR, SEN, DK 3-2 and F 1 progenies. Lethal dose estimates indicated DK 3-2 has a higher magnitude of S -metolachlor resistance than the SIR population, demonstrating single crosses significantly increased S -metolachlor resistance in DK 3-2 . Levels of S -metolachlor resistance in F 1 populations were intermediate compared to DK 3-2 and SEN. Segregation of S -metolachlor resistance in F 2 families from the paternal-derived lines fit a single-gene model (R:S = 3:1), indicating a single, dominant gene confers S -metolachlor resistance in SIR. However, F 2 segregation results from the maternal-derived lines fit a duplicate recessive epistasis model (R:S = 9:7), indicating a second recessive gene may also modify S -metolachlor resistance in SIR. Results and germplasm derived from this research can assist in identifying the gene(s) conferring resistance to S -metolachlor in A. tuberculatus .","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"83 S364","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135342673","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}
Conrad A Oberweger, Stephen F Enloe, P Chris Wilson, Candice M Prince, Benjamin P Sperry, Francisca O Hinz
Abstract Basal bark treatment with triclopyr butoxyethyl ester is used to control woody invasive plants, including Brazilian peppertree ( Schinus terebinthifolius Raddi). However, the ester formulation cannot be applied where standing water is present, which includes wetlands where S. terebinthifolius is found. In 2009, a low-volatile acid formulation of triclopyr was labeled for use in aquatic sites which allows for basal bark applications when standing water is present. This formulation may have utility for controlling woody plants in standing water. However, anecdotal observations of injury to non-target plants following applications during periods of inundation have been reported. To address this, mesocosm studies were conducted to assess non-target injury through triclopyr root exudation or release from the surface of treated stems via flooding. Mesocosms contained S. terebinthifolius as the treated target while sugarberry ( Celtis laevigata Willd.), buttonbush ( Cephalanthus occidentalis L.), and red maple ( Acer rubrum L.) were included as non-targets. In the first study, the pathway of root exudation for non-target injury following triclopyr (34 g L -1 ) basal bark application was isolated with activated charcoal placed at the soil surface. In the second study, mesocosms were flooded to assess triclopyr release from the surface of treated stems and subsequent non-target injury. Defoliation of non-target species post-treatment was ≤ 8% and triclopyr was detected at ≤ 5 µg L -1 in mesocosm wells when activated charcoal was present. Post-treatment non-target defoliation up to 92%, coupled with triclopyr concentrations in surface waters and wells as high as 4,637 µg L -1 , indicated triclopyr movement as a result of flooding. Additionally, triclopyr non-target injury from soil activity independent of flooding was observed. These findings provide limited evidence of triclopyr root exudation but considerable evidence of triclopyr release during flooding following basal bark treatment and support a cautionary approach to basal bark application when standing water is present.
摘要/ Abstract摘要:采用丁氧乙基酯三氯吡啶对巴西胡椒树(Schinus terebinthifolius Raddi)等木本入侵植物进行基皮处理。然而，酯制剂不能应用于存在死水的地方，包括发现S. terebinthifolius的湿地。2009年，一种低挥发性酸制剂三氯吡啶被标记为用于水生场所，允许在存在静水的情况下应用于基树皮。该配方可用于控制静水中的木本植物。然而，据报道，在淹没期间施用后对非目标植物造成伤害的轶事观察。为了解决这个问题，进行了中观研究，以评估通过三氯吡啶根渗出或通过淹水从处理过的茎表面释放的非靶标损伤。中观目植物以特林荫属(S. terebinthifolius)为处理目标，以糖果(Celtis laevigata Willd.)、洋油桐(Cephalanthus occidentalis L.)和红枫(Acer rubrum L.)为非处理目标。在第一项研究中，用活性炭在土壤表面分离了施用三氯吡啶(34 g L -1)后根渗出的非目标损伤途径。在第二项研究中，研究人员对经处理的茎干表面的三氯吡嗪释放和随后的非靶损伤进行了研究。处理后非目标物种的落叶率≤8%，在活性炭存在的情况下，三氯吡虫啉在介膜孔中检测到≤5µg L -1。处理后的非目标落叶率高达92%，加上地表水和井中的三氯吡啶浓度高达4,637 μ g L -1，表明三氯吡啶因洪水而移动。此外，还观察到土壤活动对三氯虫的非目标伤害，而不受洪水的影响。这些发现提供了有限的三氯吡啶根渗出的证据，但相当多的证据表明，在基树皮处理后的洪水期间，三氯吡啶释放，并支持在存在静水时使用基树皮的谨慎方法。
{"title":"Physical and Physiological Pathways of Off-Target Triclopyr Movement and Associated Non-target Injury following Basal Bark Application","authors":"Conrad A Oberweger, Stephen F Enloe, P Chris Wilson, Candice M Prince, Benjamin P Sperry, Francisca O Hinz","doi":"10.1017/wsc.2023.62","DOIUrl":"https://doi.org/10.1017/wsc.2023.62","url":null,"abstract":"Abstract Basal bark treatment with triclopyr butoxyethyl ester is used to control woody invasive plants, including Brazilian peppertree ( Schinus terebinthifolius Raddi). However, the ester formulation cannot be applied where standing water is present, which includes wetlands where S. terebinthifolius is found. In 2009, a low-volatile acid formulation of triclopyr was labeled for use in aquatic sites which allows for basal bark applications when standing water is present. This formulation may have utility for controlling woody plants in standing water. However, anecdotal observations of injury to non-target plants following applications during periods of inundation have been reported. To address this, mesocosm studies were conducted to assess non-target injury through triclopyr root exudation or release from the surface of treated stems via flooding. Mesocosms contained S. terebinthifolius as the treated target while sugarberry ( Celtis laevigata Willd.), buttonbush ( Cephalanthus occidentalis L.), and red maple ( Acer rubrum L.) were included as non-targets. In the first study, the pathway of root exudation for non-target injury following triclopyr (34 g L -1 ) basal bark application was isolated with activated charcoal placed at the soil surface. In the second study, mesocosms were flooded to assess triclopyr release from the surface of treated stems and subsequent non-target injury. Defoliation of non-target species post-treatment was ≤ 8% and triclopyr was detected at ≤ 5 µg L -1 in mesocosm wells when activated charcoal was present. Post-treatment non-target defoliation up to 92%, coupled with triclopyr concentrations in surface waters and wells as high as 4,637 µg L -1 , indicated triclopyr movement as a result of flooding. Additionally, triclopyr non-target injury from soil activity independent of flooding was observed. These findings provide limited evidence of triclopyr root exudation but considerable evidence of triclopyr release during flooding following basal bark treatment and support a cautionary approach to basal bark application when standing water is present.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"224 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135475637","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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