Variation in Response and Resistance to Glyphosate and Glufosinate in California Populations of Italian Ryegrass (Lolium perennessp.multiflorum)

Weed Science ◽  
2017 ◽  
Vol 66 (2) ◽  
pp. 168-179 ◽  
Author(s):  
Elizabeth Karn ◽  
Roland Beffa ◽  
Marie Jasieniuk
Keyword(s):  
Regression Models ◽  
Early Stage ◽  
Italian Ryegrass ◽  
Cross Resistance ◽  
Susceptible Population ◽  
High Frequencies ◽  
Logistic Regression Models ◽  
Time Period ◽  
Resistant Population ◽  
California Population

Reduced control of Italian ryegrass in California with herbicides has raised concerns about the evolution of populations with resistance to multiple herbicides. The goal of this study was to investigate variation among populations in plant response and resistance to glyphosate and glufosinate in Italian ryegrass from vineyards and orchards in northwest California. Population resistance screening using field-collected seed revealed up to 56.9% of individuals surviving glyphosate treatment at 1,678 g ae ha−1, and 53.5% of individuals surviving glufosinate treatment at 2,242 g ai ha−1in the same population. Frequencies of surviving plants within populations varied among screening times, particularly for glufosinate. Treating vegetatively propagated, genetically identical tillers with each herbicide pointed to separate mechanisms of resistance rather than cross-resistance to glyphosate and glufosinate. Dose–response experiments were conducted for each herbicide at two different screening times using a subset of populations, field-collected seed, and 10 herbicide rates. Plant survival and biomass were evaluated for each population at 3 wk after treatment and for plant regrowth 1 wk thereafter. Log-logistic regression models fit to the data were used to estimate LD50, GR50, and RD50values and calculate resistance indices (R/S ratios). Based on LD50values, the most highly resistant population was 14.4- to 19.2-fold more resistant to glyphosate than the most susceptible population tested but only 1.6- to 2.0-fold more resistant to glufosinate than the most susceptible population tested. Levels of resistance to both herbicides varied with screening time period and variable measured. Results indicate high frequencies of glyphosate-resistant plants but an early stage in the evolution of glufosinate resistance in some Italian ryegrass populations of northwest California.

scholarly journals Improving the odds? How to pick the winner of the English Derby

2014 ◽  
Vol 10 (1) ◽  
pp. 57-62
Author(s):  
D.J. Marlin ◽  
J.M. Williams ◽  
T. Parkin
Keyword(s):  
Logistic Regression ◽  
Confidence Interval ◽  
Regression Models ◽  
Mixed Effects ◽  
Point Estimate ◽  
Prize Money ◽  
Logistic Regression Models ◽  
Predictive Variables ◽  
Time Period ◽  
Predictive Probability

Many consider the English Derby on Epsom Downs to be ‘The Blue Riband of the Turf’. The Epsom Derby has been run annually since 1780 and the colt Diomed was the first winner. Today the Epsom Derby, run over 1.5 miles, is one of five classic races and is the second leg of the English Triple Crown, preceded by the 2,000 Guineas and followed by the St Leger. The prize money for 2010 has been in excess of £1.25 million. To the best of our knowledge, whilst epidemiological techniques have previously been applied in an attempt to identify risk factors for injury, the purpose of the present study, which we believe is unique, was to use an epidemiological approach to analyse factors that may be predictive of success (or failure) in a single race over the course of a number of consecutive years: The Epsom Derby. Information on the horses competing in the last 22 runnings of the Epsom Derby between 1988 and 2009. Univariate and multivariable single-level and mixed effects logistic regression models were developed using winning the Epsom Derby as the dependent variable. Between 1988 and 2009 in 22 runnings of the Derby, a total of 344 horses started the Epsom Derby. The number of runners in the race has varied between 12 and 25 over the same time period. On average the probability of winning the Derby between 1988 and 2009 was approximately 6% (22/344), without accounting for any potentially predictive variables. Variables that were related to an increased chance of success were being the favourite (odds ratio (OR) 4.75; 95 % confidence interval (CI) 1.58-14.3; P=0.006), the number of 2-year old wins (OR 1.45; CI 1.03-2.04; P=0.03), being foaled in Ireland (OR 2.80; CI 1.12-7.04; P=0.041) and having the same jockey in all races throughout the horses career up to and including the Derby (OR 2.53; CI 1.0-6.41; P=0.05). The highest predictive probability was for horses that started the race as a favourite, were Irish bred, had been ridden by a single jockey and had won twice as a 2-year old. Although the point estimate for this probability was 52% the degree of uncertainty around this estimate was wide, i.e. the 95% CI was 17.5 to 86.5%. Nevertheless even at the lower confidence interval this still represents a significant improvement on the approximately 6% chance of picking a winner at random. In conclusion, using mixed effects logistic regression models would allow one to improve the odds of picking the winner of the Epsom Derby over the past 22 runnings.

Cross-resistance to acetyl-CoA carboxylase–inhibiting herbicides conferred by a target-site mutation in perennial ryegrass (Lolium perenne) from Argentina

Weed Science ◽  
2020 ◽  
Vol 68 (2) ◽  
pp. 116-124 ◽  
Author(s):  
Marcos Yanniccari ◽  
Ramón Gigón
Keyword(s):  
Seed Production ◽  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Cross Resistance ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Plant Survival ◽  
Winter Cereal ◽  
Susceptible Population ◽  
Resistant Population

AbstractIn Argentina, Lolium spp. occur in 40% of winter cereal crops from the Pampas. Several years ago, cases of glyphosate-resistant perennial ryegrass (Lolium perenne L.) were detected, and the use of acetyl-CoA carboxylase (ACCase)-inhibiting herbicides to eradicate these plants has been considered. The aim of this study was to evaluate the sensitivity of a putative pinoxaden-resistant L. perenne population to ACCase-inhibiting herbicides. Around 80% of plants from the putative resistant population survived at a recommended dose of pinoxaden, and they produced viable seeds. The resistance indices (RIs) to pinoxaden were 5.1 and 2.8 for plant survival and seed production, respectively. A single point mutation that conferred a Asp-2078-Gly substitution in ACCase was the source of the resistance. To match the plant control achieved in the susceptible population, the resistant population required 5.4- and 10.4-fold greater doses of clethodim and quizalofop, respectively. RIs for viable seed production when treated with clethodim and quizalofop were 3.3 and 6.6, respectively. The Asp-2078-Gly mutation endowed significant levels of resistance to pinoxaden, clethodim, and quizalofop. For three herbicides, the level of resistance of a pinoxaden-resistant L. perenne population to ACCase inhibitors was evaluated, based on an evaluation of dose response for plant survival and seed production. The RIs were higher for plant survival than for seed production. In Argentina, the selection pressure associated with clethodim and haloxifop preplant application and pinoxaden use on wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) crops, would have favored the propagation of the Asp-2078-Gly mutation with its associated resistance.

Target Enzyme-Based Resistance to Clethodim inLolium rigidumPopulations in Australia

Weed Science ◽  
2015 ◽  
Vol 63 (4) ◽  
pp. 946-953 ◽  
Author(s):  
Rupinder Kaur Saini ◽  
Jenna Malone ◽  
Christopher Preston ◽  
Gurjeet Gill
Keyword(s):  
Effective Control ◽  
Cross Resistance ◽  
Single Plant ◽  
Susceptible Population ◽  
Ambient Temperatures ◽  
Resistant Population ◽  
Rigid Ryegrass ◽  
Moderately Resistant ◽  
Two Populations ◽  
Biomass Reduction

Clethodim resistance was identified in 12 rigid ryegrass populations from winter cropping regions in four different states of Australia. Clethodim had failed to provide effective control of these populations in the field and resistance was suspected. Dose–response experiments confirmed resistance to clethodim and butroxydim in all populations. During 2012, the LD50of resistant populations ranged from 10.2 to 89.3 g ha−1, making them 3 to 34–fold more resistant to clethodim than the susceptible population. Similarly, GR50of resistant population varied from 8 to 37.1 g ha−1, which is 3 to 13.9–fold higher than the susceptible population. In 2013, clethodim-resistant populations were 7.8 to 35.3–fold more resistant to clethodim than the susceptible population. The higher resistance factor in 2013, especially in moderately resistant populations, could have been associated with lower ambient temperatures during the winter of 2013. These resistant populations had also evolved cross-resistance to butroxydim. The resistant populations required 1.3 to 6.6–fold higher butroxydim dose to achieve 50% mortality and 3 to 27–fold more butroxydim for 50% biomass reduction compared to the standard susceptible population. Sequencing of the target-site ACCase gene identified five known ACCase substitutions (isoleucine-1781-leucine, isoleucine-2041-asparagine, aspartate-2078-glycine, and cysteine-2088-arginine, and glycine-2096-alanine) in these populations. In nine populations, multiple ACCase mutations were present in different individuals. Furthermore, two alleles with different mutations were present in a single plant of rigid ryegrass in two populations.

Target-Site Resistance to Fenoxaprop-P-ethyl in Keng Stiffgrass (Sclerochloa kengiana) from China

Weed Science ◽  
2017 ◽  
Vol 65 (4) ◽  
pp. 452-460 ◽  
Author(s):  
Haitao Gao ◽  
Jiaxing Yu ◽  
Lang Pan ◽  
Xibao Wu ◽  
Liyao Dong
Keyword(s):  
Eastern China ◽  
Point Mutations ◽  
Amino Acid Position ◽  
Cross Resistance ◽  
Susceptible Population ◽  
Resistant Population ◽  
Sequence Method ◽  
Moderate Resistance ◽  
High Level

Keng stiffgrass is a serious farmland grass weed distributed globally in winter wheat fields and rice–wheat double-cropping areas. The intensive use of acetyl-CoA carboxylase (ACCase)-inhibiting herbicides has led to the evolution of resistance in a growing number of grass weeds. In this study, whole-plant pot bioassay experiments were conducted to establish that a Keng stiffgrass population from eastern China, JYJD-2, has evolved high-level resistance to fenoxaprop-P-ethyl and moderate resistance to quizalofop-P-ethyl and pinoxaden. Using the derived cleaved amplified polymorphic sequence method, a tryptophan-to-cysteine mutation at codon position 1999 (W1999C) was detected in the ACCase gene of the resistant population JYJD-2. Of the 100 JYJD-2 plants tested, we found 47 heterozygous resistant and 53 homozygous sensitive individuals. In vitro ACCase assays revealed that the IC50value of the ACCase activity of the resistant population JYJD-2 was 6.48-fold higher than that of the susceptible population JYJD-1. To the best of our knowledge, this is the first report of the occurrence of W1999C mutation in the ACCase gene of fenoxaprop-P-ethyl–resistant Keng stiffgrass. This study confirmed the resistance of Keng stiffgrass to the ACCase inhibitor fenoxaprop-P-ethyl, cross-resistance to other ACCase inhibitors, and the resistance being conferred by specific ACCase point mutations at amino acid position 1999.

Patterns of Insecticide Resistance in the Mosquitofish, Gambusia affinis

1969 ◽  
Vol 26 (9) ◽  
pp. 2395-2401 ◽  
Author(s):  
Dudley D. Culley Jr. ◽  
Denzel E. Ferguson
Keyword(s):  
Insecticide Resistance ◽  
High Resistance ◽  
Gambusia Affinis ◽  
Cross Resistance ◽  
Susceptible Population ◽  
State College ◽  
Resistant Population ◽  
Resistance Patterns ◽  
Population Patterns

The extent of insecticide resistance in a resistant population of mosquitofish (Gambusia affinis) from Belzoni, Mississippi, was compared with that of a susceptible population from State College, Mississippi, using 28 insecticides of five major groups. Results of 48-hr bioassays show that resistant mosquitofish have developed high resistance only to the toxaphene–endrin related insecticides, even though insecticides from other groups were heavily applied. Spray records for the Belzoni area and insecticide characteristics such as stability and toxicity aided in evaluating cross-resistance patterns in the resistant population. Patterns of resistance in mosquitofish are similar to those in many resistant arthropods.

scholarly journals What Really Matters: The Effect of Covid-19 on the Factors of Life Satisfaction

2021 ◽  
Vol 11 (2) ◽  
pp. 18
Author(s):  
Julius Janacek
Keyword(s):  
Life Satisfaction ◽  
Czech Republic ◽  
Regression Models ◽  
Stress Relief ◽  
Drinking Alcohol ◽  
Logistic Regression Models ◽  
Difficult Time ◽  
Time Period ◽  
The City ◽  
Positive Factor

This article investigates the effect of the Covid-19 pandemic on the structure of factors of life satisfaction in the city of Usti nad Labem, Czech Republic. The dataset is based on a questionnaire survey conducted in Usti nad Labem, Czech Republic. Subsequent data analysis is conducted using ordinal logistic regression models. The results show that the emergence of the pandemic had a significant impact on life satisfaction factors. Firstly, the importance of family came to the fore: being in a relationship or being married proved to be a significant factor of life satisfaction during the pandemic but not before the pandemic. Secondly, a negative association between drinking alcohol and life satisfaction emerged during the pandemic. Alcohol probably started to be the tool for stress relief. Thirdly, sport became a significant positive factor of women’s life satisfaction. Sport most likely became an effective way of keeping oneself in balance. Results indicate that during a difficult time period there are different ways of how to deal with it. In this way doing sports and drinking alcohol seem to be substitute activities.

A Survey for Diclofop-Methyl Resistance in Italian Ryegrass from Tennessee and How To Manage Resistance in Wheat

2010 ◽  
Vol 24 (3) ◽  
pp. 303-309 ◽  
Author(s):  
Andrew T. Ellis ◽  
Lawrence E. Steckel ◽  
Christopher L. Main ◽  
Marcel S. C. De Melo ◽  
Dennis R. West ◽  
...  
Keyword(s):  
Field Experiments ◽  
Wheat Yield ◽  
Acetolactate Synthase ◽  
The United States ◽  
Research Field ◽  
Italian Ryegrass ◽  
Cross Resistance ◽  
Susceptible Population ◽  
Application Timing ◽  
Herbicide Programs

Italian ryegrass resistance to diclofop has been documented in several countries, including the United States. The purpose of this research was to screen selected putative resistant populations of Italian ryegrass for resistance to the acetyl-CoA carboxylase (ACCase)–inhibiting herbicides diclofop and pinoxaden and the acetolactate synthase (ALS)–inhibiting herbicides imazamox, pyroxsulam, and mesosulfuron in the greenhouse and to use field experiments to develop herbicide programs for Italian ryegrass control. Resistance to diclofop was confirmed in eight populations from Tennessee. These eight populations did not show cross-resistance to pinoxaden. One additional population (R1) from Union County, North Carolina, was found to be resistant to both diclofop and pinoxaden. The level of resistance to pinoxaden of the R1 population was 15 times that of the susceptible population. No resistance was confirmed to any of the ALS-inhibiting herbicides examined in this research. Field experiments demonstrated PRE Italian ryegrass control with chlorsulfuron (71 to 94%) and flufenacet + metribuzin (84 to 96%). Italian ryegrass control with pendimethalin applied PRE or delayed preemergence (DPRE) was variable (0 to 85%). POST control of Italian ryegrass was acceptable with pinoxaden, mesosulfuron, flufenacet + metribuzin, and chlorsulfuron + flucarbazone (> 80%). Application timing and herbicide treatment had no effect on wheat yield, except for diclofop and pendimethalin treatments, in which uncontrolled Italian ryegrass reduced wheat yield.

Japanese Foxtail (Alopecurus japonicus) Resistance to Fenoxaprop and Pinoxaden in China

Weed Science ◽  
2012 ◽  
Vol 60 (2) ◽  
pp. 167-171 ◽  
Author(s):  
Ibrahim A. Mohamed ◽  
Runzhi Li ◽  
Zhenguo You ◽  
Zhaohu Li
Keyword(s):  
Selection Pressure ◽  
Cross Resistance ◽  
Annual Grass ◽  
Site Mutation ◽  
Susceptible Population ◽  
Whole Plant ◽  
The World ◽  
Prior Selection ◽  
Resistant Population ◽  
Evolution Of Resistance

Japanese foxtail is one of the most common and competitive annual grass weeds of wheat in China. Whole-plant dose-response experiments were conducted with fenoxaprop and pinoxaden to confirm and characterize resistant and susceptible Japanese foxtail populations and to elucidate the basis of resistance to these herbicides. The resistant Japanese foxtail population was 49-fold resistant to fenoxaprop and 16-fold (cross) resistant to pinoxaden relative to the susceptible population, which was susceptible to both fenoxaprop and pinoxaden herbicides. Molecular analysis of resistance confirmed that the Ile1781to Leu mutation in the resistant population conferred resistance to both fenoxaprop and pinoxaden. This is the first report of cross resistance of Japanese foxtail to pinoxaden in the world and of a target site mutation that corresponded to resistance to both fenoxaprop and pinoxaden in Japanese foxtail. Prior selection pressure from fenoxaprop could result in evolution of resistance to fenoxaprop and cross resistance to pinoxaden in Japanese foxtail population.

scholarly journals Smoking, distress and COVID-19 in England: cross-sectional population surveys from 2016 to 2020

2020 ◽  
Author(s):  
Loren Kock ◽  
Lion Shahab ◽  
Jamie Brown ◽  
Graham Moore ◽  
Marie Horton ◽  
...  
Keyword(s):  
Psychological Distress ◽  
Regression Models ◽  
Mental Health Problems ◽  
Middle Age ◽  
Age Groups ◽  
Cross Sectional ◽  
Logistic Regression Models ◽  
Time Period ◽  
Chi Squared ◽  
Logistic Regressions

Background: Changes in the prevalence of mental health problems among smokers due to the COVID-19 pandemic in England have important implications for existing health inequalities. This study examined the prevalence of psychological distress among smokers following the onset of the pandemic compared with previous years. Methods: Cross-sectional data were used from a representative survey of smokers (18+) in England (n = 2,927) during four months (April to July) in 2016, 2017 and 2020. Adjusted logistic regressions estimated the associations between past-month psychological distress across two time periods (2016/17 and 2020), and age. Weighted proportions, chi-squared statistics and stratified logistic regression models were used to compare the distributions of minimal, moderate and severe distress, respectively, within socio-demographic and smoking characteristic categories in 2016/17 and 2020. Results: The prevalence of moderate and severe distress among past-year smokers was higher in 2020 (moderate: 28.79%, 95%CI 26.11-31.60; OR=2.08, 95%CI 1.34-3.25; severe: 11.04%, 9.30-13.12; OR=2.16, 1.13-4.07) than in 2016/17 (moderate: 20.66%, 19.02-22.43; severe: 8.23%, 7.16-9.47). While there was no overall evidence of an interaction between time period and age, young (16-24 years) and middle-age groups (45-54 years) may have experienced greater increases in moderate and older age groups (65+ years) in severe distress from 2016/17 to 2020. There were also increases in 2020 of moderate distress among those from more disadvantaged social grades and of both moderate and severe distress among women and those with low cigarette addiction. Conclusions: Between April-July 2016/17 and April-July 2020 in England there were increases in both moderate and severe distress among smokers. The distribution of distress differed between 2016/17 and 2020 and represents a widening of established inequalities, with increases in distress among socio-economically disadvantaged groups, women and diverging age groups.

Sign in / Sign up

Export Citation Format

Share Document