Resistance to bixlozone and clomazone in cross-resistant rigid ryegrass (Lolium rigidum) populations from southern Australia

Weed Science ◽  
2021 ◽  
pp. 1-6
Author(s):  
David J. Brunton ◽  
Gurjeet Gill ◽  
Christopher Preston
Keyword(s):  
Recurrent Selection ◽  
Selection Process ◽  
Resistance Mechanism ◽  
Fold Increase ◽  
Elevated Risk ◽  
Cross Resistance ◽  
Lolium Rigidum ◽  
Rigid Ryegrass

Abstract Three resistant (R) rigid ryegrass (Lolium rigidum Gaudin) populations from southern Australia (EP162, 375-14, and 198-15) with cross-resistance to thiocarbamate, chloroacetamide, and sulfonylisoxazoline herbicides displayed reduced sensitivity to the isoxazolidinone herbicides bixlozone and clomazone. Each of these R populations was exposed to two cycles of recurrent selection (RS) in which plants were treated with the field rate of bixlozone, survivors were bulk crossed, and seed was collected. After the first cycle of recurrent selection (RS1), the LD50 to bixlozone in population 198-15 increased to 17.5-fold compared with the S population and increased further to 26.9-fold after a second cycle of recurrent selection (RS2). The recurrent selection process also increased the level of resistance to bixlozone in populations EP162 and 375-14 (7.8- to 18.4-fold) compared with the S population. Phorate antagonized bixlozone and clomazone in SLR4 (34.6- and 28.1-fold increase in LD50) and both herbicides in populations EP162 (36.5- to 46.6-fold), 375-14 (71.4- to 73.9-fold), and 198-15 (86.4- to 91.5-fold) compared with the absence of phorate. The increase in LD50 of all L. rigidum RS populations when treated with phorate suggests a lack of herbicide activation is not the likely resistance mechanism to these herbicides. This research highlights the elevated risk of thiocarbamate-resistant L. rigidum populations to rapidly evolve resistance to the isoxazolidinone herbicides bixlozone and clomazone.

scholarly journals Inheritance of glyphosate resistance in rigid ryegrass (Lolium rigidum) from California

Weed Science ◽  
2005 ◽  
Vol 53 (5) ◽  
pp. 615-619 ◽  
Author(s):  
Marulak Simarmata ◽  
Suleiman Bughrara ◽  
Donald Penner
Keyword(s):  
First Generation ◽  
Recurrent Selection ◽  
Maternal Inheritance ◽  
Glyphosate Resistance ◽  
Segregation Ratio ◽  
Lolium Rigidum ◽  
Response Curves ◽  
Mendelian Segregation ◽  
Rigid Ryegrass ◽  
Homozygous Resistant

Glyphosate resistance was found in a rigid ryegrass population in northern California. A sample of the resistant plants were collected and grown under greenhouse conditions. The objective of this study was to evaluate glyphosate resistance in the progeny of the collected plants by recurrent selection, obtain the homozygous resistant and sensitive lines to establish dose-response curves, and to determine the inheritance of glyphosate resistance in rigid ryegrass. Diverse levels of resistance were observed in the first generation with survival of 89, 59, 45, and 9% from glyphosate at 1x, 2x, 4x, and 8x respectively, where x = 1.12 kg ha−1isopropylamine salt of glyphosate. Clones of plants that died from 1x were allowed to produce seed and were further subjected to recurrent selection to generate the most sensitive plants (S lines), which died from 0.125x glyphosate. The most resistant plants (R lines) were generated from the survivors receiving 8x glyphosate. The ratio between I50rates for the glyphosate resistant and the glyphosate sensitive plants was > 100-fold. The R and S lines were crossed reciprocally and F1progeny of both (R × S) and (S × R) showed intermediate resistance. These survived up to 2x glyphosate. The F2progeny were generated by intercrossing of F1plants. The ratio of sensitive, intermediate, and resistant plants in the F2population before the treatment of glyphosate at 0.125x followed by 8x was 1 : 16, 14 : 16, and 1 : 16 respectively, which corresponded to the Mendelian segregation ratio of two genes. The results indicated that the inheritance of glyphosate resistance in rigid ryegrass from California appeared to be nuclear, incompletely dominant, multigenic, and pollen-transmitted with no indication of maternal inheritance.

Frost Reduces Clethodim Efficacy in Clethodim-Resistant Rigid Ryegrass (Lolium rigidum) Populations

Weed Science ◽  
2016 ◽  
Vol 64 (2) ◽  
pp. 207-215 ◽  
Author(s):  
Rupinder Kaur Saini ◽  
Jenna Malone ◽  
Christopher Preston ◽  
Gurjeet S. Gill
Keyword(s):  
Dose Response ◽  
Coenzyme A ◽  
Resistance Mechanism ◽  
Lolium Rigidum ◽  
Weed Species ◽  
Susceptible Population ◽  
Acetyl Coenzyme A ◽  
Survival Percentage ◽  
Rigid Ryegrass ◽  
Acetyl Coenzyme A Carboxylase

Rigid ryegrass, an important annual weed species in cropping regions of southern Australia, has evolved resistance to 11 major groups of herbicides. Dose–response studies were conducted to determine response of three clethodim-resistant populations and one clethodim-susceptible population of rigid ryegrass to three different frost treatments (−2 C). Clethodim-resistant and -susceptible plants were exposed to frost in a frost chamber from 4:00 P.M. to 8:00 A.M. for three nights before or after clethodim application and were compared with plants not exposed to frost. A reduction in the level of clethodim efficacy was observed in resistant populations when plants were exposed to frost for three nights before or after clethodim application. In the highly resistant populations, the survival percentage and LD50were higher when plants were exposed to frost before clethodim application compared with frost after clethodim application. However, frost treatment did not influence clethodim efficacy of the susceptible population. Sequencing of the acetyl coenzyme A carboxylase (ACCase) gene of the three resistant populations identified three known mutations at positions 1781, 2041, and 2078. However, most individuals in the highly resistant populations did not contain any known mutation in ACCase, suggesting the resistance mechanism was a nontarget site. The effect of frost on clethodim efficacy in resistant plants may be an outcome of the interaction between frost and the clethodim resistance mechanism(s) present.

An Herbicide-Susceptible Rigid Ryegrass (Lolium rigidum) Population Made Even More Susceptible

Weed Science ◽  
2012 ◽  
Vol 60 (1) ◽  
pp. 101-105 ◽  
Author(s):  
Sudheesh Manalil ◽  
Roberto Busi ◽  
Michael Renton ◽  
Stephen B. Powles
Keyword(s):  
Genetic Variation ◽  
Phenotypic Variation ◽  
Recurrent Selection ◽  
Wild Population ◽  
Rapid Evolution ◽  
Differential Susceptibility ◽  
Variable Cross ◽  
Lolium Rigidum ◽  
Rigid Ryegrass ◽  
Low Rate

A wild population of a plant species, especially a cross-pollinated species, can display considerable genetic variation. Genetic variability is evident in differential susceptibility to an herbicide because the population can show continuous phenotypic variation. Recent, recurrent selection studies have revealed that phenotypic variation in response to low herbicide rates is heritable and can result in rapid evolution of herbicide resistance in genetically variable cross-pollinated rigid ryegrass. In this study, the heritable genetic variation in an herbicide-susceptible rigid ryegrass population was exploited to shift the population toward greater herbicide susceptibility by recurrent selection. To enhance herbicide susceptibility, herbicide-susceptible rigid ryegrass plants were divided into two identical clones, and one series of cloned plants was treated with a low rate of herbicide (diclofop). The nontreated clones of individuals that did not survive the herbicide treatment were selected and bulk-crossed to obtain the susceptible progeny. After two cycles of selection, the overall susceptibility to diclofop was doubled. The results indicate that minor genes for resistance are present in an herbicide-susceptible rigid ryegrass population, and their exclusion can increase susceptibility to diclofop.

Dintroaniline Herbicide Resistance in Rigid Ryegrass (Lolium rigidum)

Weed Science ◽  
1995 ◽  
Vol 43 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Fiona M. McAlister ◽  
Joseph A. M. Holtum ◽  
Stephen B. Powles
Keyword(s):  
Herbicide Resistance ◽  
Plant Material ◽  
Root Tissue ◽  
Cross Resistance ◽  
Lolium Rigidum ◽  
Green Foxtail ◽  
Low Levels ◽  
Rigid Ryegrass ◽  
Dinitroaniline Herbicides

Thirteen biotypes of rigid ryegrass were screened for trifluralin resistance. From these, the two most resistant biotypes, SLR 31 and SLR 10, were chosen for further studies involving exposure to other dinitroanilines, mitosis-inhibiting herbicides and14C-trifluralin. SLR 31, and SLR 10 exhibited an approximate 10-fold reduced sensitivity to trifluralin in comparison to susceptible biotypes. Resistance to five other dinitroaniline herbicides was observed, with reduced sensitivity varying from 32-fold for ethalfluralin to 2.5-fold for isopropalin. The resistance in rigid ryegrass to other herbicides and drugs that affect mitosis were tested. Resistance comparable to that of trifluralin was recorded for the herbicides terbutol and DCPA, while low levels of cross-resistance to amiprophosmethyl was present. Trifluralin affected mitotic indices at a much lower level in the susceptible biotypes than in the resistant biotypes. No differences in the uptake and translocation of14C-trifluralin were observed between resistant and susceptible biotypes. Most of the14C detected in the plant material was in the root tissue. A small level of14C was detected in the seeds, and no substantial increases were noted in coleoptile tissue. The resistance spectra in SLR 31 and SLR 10 were phenotypically similar to those occurring in an intermediate trifluralin-resistant goosegrass and trifluralin-resistant green foxtail.

Varying responses of field-selected herbicide-resistant rigid ryegrass (Lolium rigidum) populations to combinations of phorate with PPI herbicides

Weed Science ◽  
2020 ◽  
Vol 68 (4) ◽  
pp. 367-372
Author(s):  
David J. Brunton ◽  
Peter Boutsalis ◽  
Gurjeet Gill ◽  
Christopher Preston
Keyword(s):  
Fold Increase ◽  
Acid Synthesis ◽  
Resistance Mechanisms ◽  
Lolium Rigidum ◽  
Cytochrome P450 Enzymes ◽  
Long Chain Fatty Acid ◽  
Herbicide Resistant ◽  
Rigid Ryegrass ◽  
Sites Of Action

AbstractOrganophosphate insecticides, which have the capacity to inhibit specific herbicide-degrading (cytochrome P450) enzymes, have been used to explore metabolic herbicide-resistance mechanisms in weeds. This study investigates the response of seven field-selected rigid ryegrass (Lolium rigidum Gaudin) populations to herbicides from three different sites of action in the presence or absence of the P450 inhibitor phorate. Phorate antagonized the thiocarbamate herbicides triallate and prosulfocarb (8-fold increase in LD50) in multiple resistant L. rigidum populations with resistance to three different site-of-action herbicides. In contrast, phorate synergized trifluralin and propyzamide in some populations, reducing the LD50 by 50%. Conversely, treatment with phorate had no significant effect on the LD50 for S-metolachlor or pyroxasulfone (inhibitors of very-long-chain fatty-acid synthesis). Phorate has diverse effects that are herbicide and population dependant in field-selected L. rigidum, suggesting P450 involvement in the metabolism of trifluralin and failure to activate thiocarbamate herbicides in these populations. This research highlights the need for implementation of diverse approaches other than herbicide alone as part of a long-term integrated strategy to reduce the likelihood of metabolism-based resistance to PPI herbicides in L. rigidum.

Resistance to Nine Herbicide Classes in a Population of Rigid Ryegrass (Lolium rigidum)

Weed Science ◽  
1994 ◽  
Vol 42 (3) ◽  
pp. 369-377 ◽  
Author(s):  
Michael W. M. Burnet ◽  
Quentin Hart ◽  
Joseph A. M. Holtum ◽  
Stephen B. Powles
Keyword(s):  
Cross Resistance ◽  
Lolium Rigidum ◽  
Small Shift ◽  
Susceptible Population ◽  
Three Generations ◽  
Small Change ◽  
Rigid Ryegrass ◽  
High Level ◽  
Dinitroaniline Herbicides

Rigid ryegrass population VLR69 has become resistant to nine classes of herbicides after 21 yr of exposure to five herbicides in five different chemical classes. The population was exposed to diuron in 17 seasons and is resistant to diuron (4 fold) and chlorotoluron (8 fold) when compared with a reference susceptible population (VLR1). VLR69 had six seasons of exposure to chlorsulfuron and exhibits a high level of resistance to chlorsulfuron (> 20 fold) and triasulfuron (> 25 fold) and a lesser change in sensitivity to sulfometuron (7 fold); however, 4% of the population has a high level of resistance to sulfometuron. Resistance to atrazine (5 fold), simazine (6 fold), and ametryn (10 fold) was observed after five seasons of exposure to atrazine. There is a high level of resistance to all aryloxyphenoxypropionate herbicides after only two exposures to diclofop eight generations prior to testing the population. The population was cross-resistant to tralkoxydim (> 9.5 fold) and sethoxydim (1.8 fold). There was a small change in sensitivity to paraquat (1.4 fold) after three generations of exposure. The population displayed cross-resistance to: imazaquin (7 fold), imazapyr (2.5 fold), metribuzin (8.7 fold), and metolachlor (2 fold) but was susceptible to oxyfluorfen and dinitroaniline herbicides. There was also a small shift in sensitivity to tridiphane (1.6 fold).

Chloroacetamide Resistance in Rigid Ryegrass (Lolium rigidum)

Weed Science ◽  
1994 ◽  
Vol 42 (2) ◽  
pp. 153-157 ◽  
Author(s):  
Michael W. M. Burnet ◽  
Andrew R. Barr ◽  
Stephen B. Powles
Keyword(s):  
Avena Sativa ◽  
High Probability ◽  
Cross Resistance ◽  
Lolium Rigidum ◽  
Germination Test ◽  
Herbicide Resistant ◽  
Relative Response ◽  
Germination Medium ◽  
Rigid Ryegrass

Metolachlor has been evaluated both as a herbicide for use in cultivated oats (Avena sativaL.) and for its potential as an alternative herbicide for the control of herbicide-resistant rigid ryegrass. Eight herbicide-resistant and two susceptible biotypes of rigid ryegrass were tested for their susceptibility to metolachlor. Response to metolachlor was determined both in soil and an agar germination medium. The LD50for metolachlor in agar for a susceptible biotype (VLR1) was 0.13 μM. Five biotypes, SLR5 (6.9 fold), SLR31 (5.2 fold), SLR10 (2.5 fold), NLR12 (2.1 fold) and VLR69 (1.9 fold), were cross-resistant to metolachlor when compared with VLR1. Relative response of the biotypes was similar in both soil and agar, validating the use of an agar germination test to determine the susceptibility of rigid ryegrass biotypes to metolachlor. Biotypes cross-resistant to metolachlor also were cross-resistant to alachlor (SLR5 6.7 fold, SLR31 5.9 fold, SLR10 2.4 fold, and VLR69 1.6 fold with the LD50for VLR1 being 0.49 μM) and propachlor (SLR57.2 fold, SLR31 7.2 fold, SLR10 3.0 fold and VLR69 2.5 fold with the LD50for VLR1 being 0.47 μM) indicating that cross-resistance extends to other members of the chloroacetamide group. Cross-resistance to chloroacetamides was observed in biotypes that previously had been reported as cross-resistant to other herbicides. In contrast, biotypes with limited herbicide histories were generally not cross-resistant to metolachlor. These results indicate that there is a high probability of chloroacetamide cross-resistance in populations of herbicide-resistant rigid ryegrass.

Evolved resistance to glyphosate in rigid ryegrass (Lolium rigidum) in Australia

Weed Science ◽  
1998 ◽  
Vol 46 (5) ◽  
pp. 604-607 ◽  
Author(s):  
Stephen B. Powles ◽  
Debrah F. Lorraine-Colwill ◽  
James J. Dellow ◽  
Christopher Preston
Keyword(s):  
Dose Response ◽  
Glyphosate Resistance ◽  
Cross Resistance ◽  
Lolium Rigidum ◽  
Weed Species ◽  
Susceptible Population ◽  
Use Patterns ◽  
Rigid Ryegrass ◽  
Susceptible Populations ◽  
Grass Weed

Following 15 yr of successful use, glyphosate failed to control a population of the widespread grass weed rigid ryegrass in Australia. This population proved to be resistant to glyphosate in pot dose-response experiments conducted outdoors, exhibiting 7- to 11-fold resistance when compared to a susceptible population. Some cross-resistance to diclofop-methyl (about 2.5-fold) was also observed. Similar levels of control of the resistant and susceptible populations were obtained following application of amitrole, chlorsulfuron, fluazifop-P-butyl, paraquat, sethoxydim, sirnazine, or tralkoxydim. The presence of glyphosate resistance in a major weed species indicates a need for changes in glyphosate use patterns.

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