scholarly journals Triple-resistant kochia [Kochia scoparia (L.) Schrad.] in Alberta

2019 ◽  
Vol 99 (2) ◽  
pp. 281-285 ◽  
Author(s):  
Hugh J. Beckie ◽  
Linda M. Hall ◽  
Scott W. Shirriff ◽  
Elise Martin ◽  
Julia Y. Leeson

A randomized stratified survey was conducted in Alberta in 2017 to determine the distribution and abundance of multiple-resistant [acetolactate synthase (ALS) inhibitor, glycine, and synthetic auxin] kochia. All populations were ALS inhibitor resistant, with glyphosate and dicamba resistance confirmed in 50% and 18% of populations, respectively. Ten percent of populations exhibited resistance to all three mode-of-action herbicides.

2012 ◽  
Vol 26 (3) ◽  
pp. 570-574 ◽  
Author(s):  
Hugh J. Beckie ◽  
Eric N. Johnson ◽  
Anne Légère

This greenhouse experiment examined the response of homozygous susceptible and acetolactate synthase (ALS) inhibitor–resistant plants from six Canadian kochia accessions with the Pro197 or Trp574 mutation to six alternative herbicides of different sites of action. The null hypothesis was ALS-inhibitor–resistant and –susceptible plants from within and across accessions would respond similarly to herbicides of different sites of action. This hypothesis was accepted for all accessions except that of MBK2 with the Trp574 mutation. Resistant plants of that accession were 80, 60, and 50% more sensitive than susceptible plants to pyrasulfotole, mesotrione (hydroxyphenylpyruvate dioxygenase [HPPD] inhibitors), and carfentrazone (protoporphyrinogen oxidase [PPO] inhibitor), respectively. However, no differential dose response between resistant and susceptible plants of this kochia accession to bromoxynil, fluroxypyr, or glyphosate was observed. A previous study had found marked differences in growth and development between resistant and susceptible plants of this accession, but not of the other accessions examined in this experiment. Negative cross-resistance exhibited by resistant plants of accession MBK2 to PPO and HPPD inhibitors in this experiment may be a pleiotropic effect related to the Trp574 mutation.


2011 ◽  
Vol 25 (1) ◽  
pp. 170-175 ◽  
Author(s):  
Hugh J. Beckie ◽  
Suzanne I. Warwick ◽  
Connie A. Sauder ◽  
Chris Lozinski ◽  
Scott Shirriff

A survey of 109 fields was conducted across western Canada in spring 2007 to determine the extent of ALS-inhibitor and dicamba (synthetic auxin) resistance in kochia. Weed seedlings were collected from fields in three provinces of western Canada and transplanted into the greenhouse. Seeds were harvested from selfed plants, and the F1progeny were screened for resistance to the ALS-inhibitor mixture thifensulfuron–tribenuron or dicamba. All kochia populations were susceptible to dicamba. ALS inhibitor–resistant kochia was found in 85% of the fields surveyed in western Canada: 80 of 95 fields in Alberta, six of seven fields in Saskatchewan, and all seven fields in Manitoba. For the 93 ALS inhibitor–resistant populations, the mean frequency (±SE) of parental plants classified as resistant was 61 ± 3%. Most of the resistant populations (87%) were heterogeneous and contained both resistant and susceptible individuals.ALSsequence data (Pro197and Asp376mutations) and genotyping data (Trp574mutation) obtained for 87 kochia parental (i.e., field-collected) plants confirmed the presence of all three target-site mutations as well as two mutational combinations (Pro197+ Trp574, Asp376+ Trp574) in resistant individuals.


2014 ◽  
Vol 94 (8) ◽  
pp. 1407-1411 ◽  
Author(s):  
Nikki Burton ◽  
Scott W. Shirriff ◽  
Hugh J. Beckie

Burton, N., Shirriff, S. W. and Beckie, H. J. 2014. Response of glyphosate-resistant kochia (Kochia scoparia L. Schrad.) to alternative herbicides. Can. J. Plant Sci. 94: 1407–1411. A greenhouse study was conducted to examine the response of glyphosate-resistant (GR) plus acetolactate synthase (ALS) inhibitor-resistant kochia to five post-emergence herbicide treatments commonly used to control the weed species in chemical fallow, cereals, or oilseed crops in western Canada. The treatments, which were applied to two GR kochia biotypes and one non-GR (susceptible) biotype, included the labeled rate of dicamba, dicamba/fluroxypyr, dicamba/diflufenzopyr, MCPA/bromoxynil, and glufosinate. Both GR and non-GR biotypes responded similarly to each of the herbicide treatments. Although both GR biotypes were sensitive to the herbicides, MCPA/bromoxynil was the most effective treatment in reducing shoot biomass 3 wk after application (99%), followed by glufosinate (91%) then the dicamba mixtures (82%). Dicamba alone only suppressed kochia biomass (76% reduction).


Weed Science ◽  
2016 ◽  
Vol 64 (4) ◽  
pp. 624-633 ◽  
Author(s):  
Hugh J. Beckie ◽  
Robert E. Blackshaw ◽  
Linda M. Hall ◽  
Eric N. Johnson

Efficient natural dispersal of herbicide-resistance alleles via seed and pollen can markedly accelerate the incidence of herbicide-resistant weed populations across an agroecoregion. Studies were conducted in western Canada in 2014 and 2015 to investigate pollen- and seed-mediated gene flow in kochia. Pollen-mediated gene flow (PMGF) from glyphosate-resistant (GR) to non-GR kochia was quantified in a field trial (hub and spoke design) at Saskatoon, Saskatchewan. Seed-mediated gene flow of acetolactate synthase (ALS) inhibitor-resistant kochia as a function of tumbleweed speed and distance was estimated in cereal stubble fields at Lethbridge, Alberta and Scott, Saskatchewan. Regression analysis indicated that outcrossing from GR to adjacent non-GR kochia ranged from 5.3 to 7.5%, declining exponentially to 0.1 to 0.4% at 96 m distance. However, PMGF was significantly influenced by prevailing wind direction during pollination (maximum of 11 to 17% outcrossing down-wind). Seed dropped by tumbleweeds varied with distance and plant speed, approaching 90% or more (ca. 100,000 seeds or more) at distances of up to 1,000 m and plant speeds of up to 300 cm s–1. This study highlights the efficient proximal (pollen) and distal (seed) gene movement of this important GR weed.


2016 ◽  
Vol 8 (10) ◽  
pp. 54
Author(s):  
Neha Rana ◽  
Amit J. Jhala

<p>Kochia is an early emerging weed of increasing concern across the Great Plains region of the United States due to the evolution of resistance to herbicides. Greenhouse studies were conducted to confirm and characterize the level of glyphosate and acetolactate synthase (ALS)-inhibiting herbicide resistance in kochia biotype collected from a field in Sheridan County in Nebraska. The response of kochia biotype to 9 rates (0 to 16×) of tribenuron and glyphosate was evaluated in a whole plant dose-response bioassay. On the basis of the values at the 90% effective dose (ED<sub>90</sub>), the putative-resistant kochia biotype had a 6- and 15-fold level of resistance to glyphosate and tribenuron, respectively. Future research will evaluate strategies for the management of glyphosate- and ALS-resistant kochia under field conditions.</p>


Weed Science ◽  
1995 ◽  
Vol 43 (2) ◽  
pp. 175-178 ◽  
Author(s):  
Mary J. Guttieri ◽  
Charlotte V. Eberlein ◽  
Donald C. Thill

The DNA sequence of an 83-base pair region of the acetolactate synthase (ALS) gene was compared for 10 chlorsulfuron-resistant (R) and three chlorsulfuron-susceptible (S) kochia biotypes. Point mutation in the codon for the proline residue at position 173 in Domain A of the ALS protein was observed in seven of 10 R biotypes. Among these seven R biotypes, mutation to threonine, serine, arginine, leucine, glutamine, and alanine was identified. The mechanism of resistance was determined for the R biotypes that did not have mutation in Domain A; all were resistant due to modified ALS, which indicated that at least one non-Domain A mutation site for resistance exists in kochia. Sequence results indicate that multiple mutations for resistance have occurred, and that geographically widespread ALS-inhibitor resistance in kochia is not the result of a single resistance allele.


Weed Science ◽  
2021 ◽  
pp. 1-25
Author(s):  
Qian Yang ◽  
Xia Yang ◽  
Zichang Zhang ◽  
Jieping Wang ◽  
Weiguo Fu ◽  
...  

Abstract Barnyardgrass (Echinochloa crus-galli) is a noxious grass weed which infests rice fields and causes huge crop yield losses. In this study, we collected twelve E. crus-galli populations from rice fields of Ningxia province in China and investigated the resistance levels to acetolactate synthase (ALS) inhibitor penoxsulam and acetyl-CoA carboxylase (ACCase) inhibitor cyhalofop-butyl. The results showed that eight populations exhibited resistance to penoxsulam and four populations evolved resistance to cyhalofop-butyl. Moreover, all of the four cyhalofop-butyl-resistant populations (NX3, NX4, NX6 and NX7) displayed multiple-herbicide-resistance (MHR) to both penoxsulam and cyhalofop-butyl. The alternative herbicides bispyribac-sodium, metamifop and fenoxaprop-P-ethyl cannot effectively control the MHR plants. To characterize the molecular mechanisms of resistance, we amplified and sequenced the target-site encoding genes in resistant and susceptible populations. Partial sequences of three ALS genes and six ACCase genes were examined. A Trp-574-Leu mutation was detected in EcALS1 and EcALS3 in two high-level (65.84- and 59.30-fold) penoxsulam-resistant populations NX2 and NX10, respectively. In addition, one copy (EcACC4) of ACCase genes encodes a truncated aberrant protein due to a frameshift mutation in E. crus-galli populations. None of amino acid substitutions that are known to confer herbicide resistance were detected in ALS and ACCase genes of MHR populations. Our study reveals the widespread of multiple-herbicide resistant E. crus-galli populations at Ningxia province of China that exhibit resistance to several ALS and ACCase inhibitors. Non-target-site based mechanisms are likely to be involved in E. crus-galli resistance to the herbicides, at least in four MHR populations.


2021 ◽  
pp. 1-22
Author(s):  
Vijay K. Choudhary ◽  
Seshadri S. Reddy ◽  
Subhash K. Mishra ◽  
Bhumesh Kumar ◽  
Yogita Gharde ◽  
...  

Abstract Smallflower umbrella sedge is one of the problematic weeds in direct-seeded rice in India. Bispyribac-sodium (acetolactate synthase-inhibiting herbicide) is a commonly used in rice, but recently growers have reported lack of smallflower umbrella sedge control with this herbicide. An extensive survey was carried out in two rice growing states, Chhattisgarh and Kerala, where 53 putative bispyribac-sodium resistant (BR) biotypes were collected. Studies were conducted to confirm resistance to bispyribac-sodium and to test the efficacy of newly developed synthetic auxin herbicide florpyrauxifen-benzyl on putative BR biotypes. Whole-plant bioassay revealed that bispyribac-sodium is no longer effective. Of 53 putative BR biotypes, 17 biotypes survived recommended label rate of 25 g ai ha−1. Effective bispyribac-sodium rate required to control 50% of the plants in most of the BR biotypes (ED50) ranged from 19 to 96 g ha−1 whereas it was 10 g ha−1 in susceptible biotype. In two highly resistant biotypes, ED50 was beyond the maximum tested rate, 200 g ha−1. This suggests 2 to >20-fold resistance in BR biotypes. Acetolactate synthase (ALS) enzyme activity assay suggests altered target site as mechanism of resistance to bispyribac-sodium. This study confirms the first case of evolved resistance in smallflower umbrella sedge for bispyribac-sodium in India. However, the newly developed synthetic auxin, florpyrauxifen-benzyl effectively controlled all BR biotypes at the field use rate 31.25 g ae ha−1.


Author(s):  
Alysha T Torbiak ◽  
Robert Blackshaw ◽  
Randall N Brandt ◽  
Bill Hamman ◽  
Charles M. Geddes

Kochia [Bassia scoparia (L.) A.J. Scott] is an invasive C4 tumbleweed in the Great Plains of North America, where it impedes crop harvest and causes significant crop yield losses. Rapid evolution and spread of glyphosate- and acetolactate synthase (ALS) inhibitor-resistant kochia in western Canada limit the herbicide options available for control of these biotypes in field pea (Pisum sativum L.); one of the predominant pulse crops grown in this region. Field experiments were conducted near Lethbridge, Alberta in 2013-2015 and Coalhurst, Alberta in 2013-2014 to determine which herbicide options effectively control glyphosate- and ALS inhibitor-resistant kochia in field pea. Visible injury of field pea was minor (0-4%) in all environments except for Lethbridge 2013, where pre-plant (PP) flumioxazin and all treatments containing post-emergence (POST) imazamox/bentazon resulted in unacceptable (14-23%) pea visible injury. Herbicide impacts on pea yield were minor overall. Carfentrazone + sulfentrazone PP and saflufenacil PP followed by imazamox/bentazon POST resulted in ≥80% visible control of kochia in all environments, while POST imazamox/bentazon alone resulted in ≥80% reduction in kochia biomass in all environments compared with the untreated control (albeit absent of statistical difference in Coalhurst 2014). These results suggest that layering the protoporhyrinogen oxidase-inhibiting herbicides saflufenacil or carfentrazone + sulfentrazone PP with the ALS- and photosystem II-inhibiting herbicide combination imazamox/bentazon POST can effectively control glyphosate- and ALS inhibitor-resistant kochia in field pea while also mitigating further selection for herbicide resistance through the use of multiple effective herbicide modes-of-action.


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