Thesis
An ALA122THR substitution confers imazamox-resistance in jointed goatgrass (Aegilops cylindrica host.)
Washington State University
Master of Science (MS), Washington State University
2018
Handle:
https://hdl.handle.net/2376/105578
Abstract
Wheat growers have limited herbicide options to manage jointed goatgrass (Aegilops cylindrica Host), with many relying on imazamox or mesosulfuron in combination with Clearfield™ winter wheat. Both imazamox and mesosulfuron inhibit acetohydroxyacid synthase/acetolactate synthase (AHAS/ALS). In 2015, a suspected imazamox resistant biotype of jointed goatgrass was found in eastern Washington. In an effort to understand the mechanism of resistance, mesosulfuron and imazamox were applied to the suspected resistant and susceptible jointed goatgrass biotypes in increasing concentrations to evaluate herbicide dose needed to cause 50% injury (I50). Increasing concentrations of imazamox and mesosulfuron were applied to both the resistant and a susceptible jointed goatgrass biotype to test for resistance. The resulting dose response indicated, imazamox resistant biotype had a I50 of 308.5 g ai ha-1 that is 14 times more resistant to imazamox than the known susceptible biotype with a I50 of 21.7 g ai ha-1 . Results for the mesosulfuron dose response demonstrated the resistant biotype has an I50 of 46.82 g ai ha-1 that was five time more resistant than the susceptible with an I50 of 8.6 g ai ha-1 . An imazamox field use rate of 12.3 times the recommended rate of 52.5 g ai ha-1 would be necessary to achieve 50% injury. Sequencing efforts in the ALS gene reveal an Ala122Thr substitution in the herbicide binding region of the ALS gene on the D-genome of jointed goatgrass. Thus, the Ala122Thr substitution on the D genome of jointed goatgrass confers a high level of resistance to imazamox.
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Details
- Title
- An ALA122THR substitution confers imazamox-resistance in jointed goatgrass (Aegilops cylindrica host.)
- Creators
- Jeanette Adriana Rodriguez
- Contributors
- Ian Cristofer Burke (Chair)Arron Hyrum Carter (Committee Member) - Washington State University, Crop and Soil Sciences, Department ofKaren Sanguinet (Committee Member) - Washington State University, Crop and Soil Sciences, Department of
- Awarding Institution
- Washington State University
- Academic Unit
- Crop and Soil Sciences, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525295301842
- Language
- English
- Resource Type
- Thesis