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United States Department of Agriculture

Agricultural Research Service

Research Project: Management Strategies to Sustain Irrigated Agriculture with Limited Water Supplies

Location: Water Management Research

Title: Confirmation of resistance to herbicides and evaluation of resistance levels

Authors
item Burgos, Nilda -
item Tranel, Patrick -
item Streibig, Jens -
item Davis, Vince -
item Shaner, Dale
item Norswhorthy, J -

Submitted to: Weed Science
Publication Type: Review Article
Publication Acceptance Date: July 1, 2012
Publication Date: N/A

Interpretive Summary: This paper reviews multiple methods for testing herbicide resistance in weeds and the strengths and weaknesses of each method.

Technical Abstract: As cases of resistance to herbicides escalate worldwide, there is increasing demand from growers to test for weed resistance and how to manage it. Scientists have developed resistance testing protocols for numerous herbicides and weed species. Growers need immediate answers and scientists are faced with the daunting task of testing an increasingly large number of samples across a variety of species and herbicides. Quick tests have been, and continue to be, developed to address this need, although classical tests are still the norm. Newer methods involve molecular techniques. Whereas the classical whole-plant assay tests for resistance regardless of the mechanism, many quick tests are limited by specificity to a herbicide, mode of action, or mechanism of resistance. Advancing knowledge in weed biology and genomics allows for refinements in sampling and testing protocols. Thus, approaches in resistance testing continue to diversify, which can confound the less experienced. We aim to help weed science practitioners resolve questions pertaining to the testing of herbicide resistance starting with field surveys and sampling methods, herbicide screening methods, data analysis, and finally, interpretation. More specifically this paper discusses approaches for sampling plants for resistance confirmation assays, provides brief overviews on the biological and statistical basis for designing and analyzing dose response tests, as well as discusses alternative procedures for rapid resistance confirmation including molecular-based assays. Resistance confirmation procedures often need to be slightly modified to suit a specific situation; thus, the general requirements as well as pros and cons of quick assays and DNA-based assays are contrasted. Ultimately, weed resistance testing research, as well as resistance management decisions arising from research, needs to be practical, feasible, and grounded in science-based methods.

Last Modified: 7/28/2014
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