Study: Herbicide Resistant Palmer Amaranth Weeds Show Fitness, Persistence

Palmer amaranth is a weed native to the southwestern U.S. that has developed resistance to various herbicides since the late 1980s. Its resistance to glyphosate was first confirmed in 2006 in Macon County, Georgia, and has since spread to 13 states. Palmer amaranth, which is capable of producing more than 600,000 seeds per female plant, significantly affects crop yields throughout the southern U.S.

An article featured in the current issue of Weed Science offers results from a greenhouse experiment focused on how resistance might affect the continued fitness of Palmer amaranth plants by comparing glyphosate-resistant plants to glyphosate-susceptible plants.

The mechanism of resistance studied in this population was amplification of the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene. Palmer amaranth growth rate, height and volume, final biomass, photosynthetic rate, length of inflorescence, pollen variability and seed set were evaluated. If measures of plant growth, such as height and volume, showed a positive correlation with the EPSPS gene, this would suggest good fitness of the resistant plant. Fecundity-related measures, such as shorter inflorescence and increased number of days to first flower, could indicate a cost in the fitness of the resistant plant. Metabolic overproduction of the enzyme and disruption to other genes could potentially weaken the plant.

Some resistant plants had more than 100 EPSPS genes, but this study did not identify a fitness cost for resistant Palmer amaranth. The amplified EPSPS gene did not cause the plant to work harder or to divert resources to fight the herbicide. This means that glyphosate resistance will probably persist, making it unlikely that susceptible Palmer amaranth would once again become dominant if glyphosate use was discontinued. Farmers will continue to be faced with finding different methods of removing Palmer amaranth from their fields.

Aspects of this study also show the importance of controlling for genetic background when estimating fitness costs. Great variation was found in fitness measures even between sibling plants from the same family. Without a diverse sample, it could be concluded that these differences were due to the amplified EPSPS gene. These study results could also be used to develop a resistance evolution simulation model to help predict and guide future weed management.

Read the full text of the article, “Impact of Genetic Background in Fitness Cost Studies: An Example from Glyphosate-Resistant Palmer Amaranth,” Weed Science, Vol. 62, No. 1, January–March 2014, is now available.

Topics:

Leave a Reply

One comment on “Study: Herbicide Resistant Palmer Amaranth Weeds Show Fitness, Persistence

Herbicides Stories

Crop InputsArkansas Plant Board Votes to Ban Dicamba — Now What?
June 23, 2017
The Arkansas State Plant Board has voted to pass a proposed emergency rule to ban the use of in-crop dicamba, Read More
Engenia soybeans
Crop InputsBASF: ‘Closely Monitoring’ Dicamba Situation in Arkansas
June 22, 2017
BASF, whose Engenia herbicide is the target of more than 200 drift complaints in Arkansas, emailed the following statement to Read More
Palmer pigweed seedhead in cotton
Crop InputsThreat of Dicamba Ban Looms in Arkansas
June 22, 2017
The Arkansas State Plant Board has rejected a proposed ban on the use of dicamba herbicide, but a procedural error Read More
Power to Do More Contest Winners
HerbicidesDow AgroSciences Announces Three Winners in Power to Do More Contest
June 13, 2017
Thousands of votes have been cast and three farmers have been awarded the power to do more with a $10,000 Read More
Trending Articles
PrecisionAg Vision Conference
Precision AgPrecisionAg® Vision Conference: Focused on the Future
June 13, 2017
PrecisionAg® is pleased to announce the return of its PrecisionAg Vision Conference, October 10-12, 2017. Based on overwhelmingly positive response Read More
Redbanded-stinkbug-on-soybean-Photo-credit-Thomas-County-Ag
Crop InputsExperts: Mild Winter, Early Planting Will Increase Soybean Insect Threat
June 12, 2017
Higher than average temperatures this past winter affected much of the nation, especially the South and Midwest. The National Centers Read More
Eric SfiligojMonsanto ‘Picks Its Battles’ by Nixing Deere Deal
May 23, 2017
Having been in the trade journalism game since the mid-1980s, I remember several watershed moments during my career. One of Read More
Migrant farm workers
LegislationTrump: Immigration Crackdown Won’t Impact U.S. Agriculture
May 16, 2017
President Donald Trump said he would seek to keep his tough immigration enforcement policies from harming the U.S. farm industry Read More
AGCO Ratliff featured
Eric SfiligojRemembering Robert Ratliff
May 15, 2017
With all the fast-paced happenings in agriculture this spring, with multiple mergers in the works and planting season in full Read More
Case sprayer nozzle closeup
EquipmentSpray Application: A Nozzle Renaissance
May 2, 2017
If you had asked four-decade ag veteran Mark Bartel, President of Wilger Inc., just a few years ago what lay Read More
Latest News
Crop InputsArkansas Plant Board Votes to Ban Dicamba — Now W…
June 23, 2017
The Arkansas State Plant Board has voted to pass a proposed emergency rule to ban the use of in-crop dicamba, Read More
Engenia soybeans
Crop InputsBASF: ‘Closely Monitoring’ Dicamba Situatio…
June 22, 2017
BASF, whose Engenia herbicide is the target of more than 200 drift complaints in Arkansas, emailed the following statement to Read More
ManagementConsolidation Update
June 22, 2017
Editors Paul Schrimpf and Eric Sfiligoj discuss progress on manufacturer consolidation, and another big move for Midwest cooperative Central Valley Read More
Palmer pigweed seedhead in cotton
Crop InputsThreat of Dicamba Ban Looms in Arkansas
June 22, 2017
The Arkansas State Plant Board has rejected a proposed ban on the use of dicamba herbicide, but a procedural error Read More
Potash Agrium
Crop InputsAgrium-PotashCorp to become Nutrien upon Merger Complet…
June 21, 2017
Potash Corporation of Saskatchewan Inc. and Agrium Inc. have announced today that once the anticipated merger transaction closes, the new Read More
Crop InputsMidwestern BioAg Hosts TerraNu Fertilizer Plant Opening…
June 20, 2017
Last Friday, Midwestern BioAg was joined by over 80 local farmers, media and staff to celebrate the grand opening of Read More
Soybean Field
Industry NewsAligned Ag Distributors Names New President
June 19, 2017
Aligned Ag Distributors LLC announced this morning the appointment of Mary Tolke to the position of President/CEO, effective July 1. Read More
ManagementPlotting Corn, AGCO/Asmark’s Applicator Training Center…
June 15, 2017
Editors Paul Schrimpf and Eric Sfiligoj talk about their recent visits to Columbus, OH, and Bloomington, IL, along with an Read More
Seed/BiotechDow AgroSciences Announces Launch of Enlist Corn for 20…
June 14, 2017
Enlist corn will be commercially available in the U.S. for the 2018 growing season. Dow AgroSciences announced the launch today Read More
ASMARK AGCO Applicator Training Center
EmployeesAsmark, AGCO Open Training Center for Beginning Applica…
June 13, 2017
AGCO Corp. and the Asmark Institute have opened a new Applicator Training Center, created in a collaboration between the two Read More
Power to Do More Contest Winners
HerbicidesDow AgroSciences Announces Three Winners in Power to Do…
June 13, 2017
Thousands of votes have been cast and three farmers have been awarded the power to do more with a $10,000 Read More
Frogeye leaf spot
FungicidesStrobilurin-resistant Frogeye Leaf Spot Threat Looms wi…
June 13, 2017
Heavy spring rainfall throughout the South and Midwest delayed planting and created the perfect environment for diseases like frogeye leaf Read More
PrecisionAg Vision Conference
Precision AgPrecisionAg® Vision Conference: Focused on the Future
June 13, 2017
PrecisionAg® is pleased to announce the return of its PrecisionAg Vision Conference, October 10-12, 2017. Based on overwhelmingly positive response Read More
CHS St. Paul, MN fertilizer terminal
LegislationICGA Praises President Trump’s Remarks on Waterwa…
June 12, 2017
Illinois Corn Growers Association President Justin Durdan, a farmer from Utica, issued the following statement regarding President Donald Trump’s comments Read More
Wheat Growers
UncategorizedWheat Growers Names Tracy Linbo as Senior Vice Presiden…
June 12, 2017
Wheat Growers has hired Tracy Linbo as Senior Vice President of Agronomy. Linbo joins Wheat Growers after having served 10 Read More
EquipmentAgTech Summit Aiming High for Modern Farming Solutions
June 12, 2017
THRIVE AgTech, in partnership with SVG Partners and Forbes, is hosting the third annual Forbes AgTech Summit June 28-29 in Read More
Central Valley Ag Randolph, NE
Precision AgLand O’Lakes Invests in EFC Systems
June 12, 2017
Land O’Lakes, Inc. has made a minority equity investment in EFC Systems, Inc., an ERP (Enterprise Resource Planning) and precision Read More
BRANDT
Crop InputsBRANDT Products Approved for Use with New Cropping Syst…
June 12, 2017
BRANDT, a leading manufacturer of specialty products for the agriculture and turf markets, has announced that 11 BRANDT formulations have Read More