Thesis
Acetolactate synthase herbicide resistance in the dryland regions of Eastern Washington
Washington State University
Master of Science (MS), Washington State University
05/2016
Handle:
https://hdl.handle.net/2376/101497
Abstract
Wheat has the largest number of identified herbicide resistant weed species compared to other crops world-wide. The high occurrence of resistance could possibly due to growers’ reliance on acetyl CoA carboxylase (ACCase) inhibiting and acetolactate synthase (ALS) inhibiting herbicides for postemergence grass weed control. Since 1988, ALS-inhibiting herbicides have been plagued by increasing numbers of ALS-resistant weed species worldwide. Growers in Washington have considerable concern about increasing ALS-inhibitor resistance development among weed populations. In an initial effort to understand the prevalence of ALS-inhibitor resistance in Washington, growers were encouraged to submit weed biotypes with suspected herbicide resistance to the Weed Science program at Washington State University. The objectives of the studies presented are to determine the mechanism conferring cross-resistance to multiple ALS-inhibitors in a shepherd’s-purse [Capsella bursa-pastoris (L.) Medic] biotype found in the Pacific Northwest and provide an overview of ALS-inhibitor resistance in Washington. No differences in metabolism, absorption and translocation were found between the resistant and a known susceptible shepherd’s-purse biotypes. Initial sequencing efforts did not identify a known target-site mutation in the resistant shepherd’s-purse biotype. However, closer investigation identified two nucleic acid peaks, guanine (G) and thymine (T), at position 574 in the ALS genomic DNA sequence, suggesting the presence of a SNP in the resistant biotype at Trp754. Therefore, further studies will be conducted to validate the SNP of thymine (TTG) at position 574 in the resistant biotype as the target-site mechanism conferring ALS-inhibitor resistance. Results from the grower submission confirmed ALS-inhibitor resistance in 83% of the weed biotypes screened. The portion of resistance confirmed during the study indicates resistance to ALS-inhibitors is present in Eastern Washington. The study also demonstrate many growers and industry professionals are aware of the resistance present in their field. A randomized weed survey should be conducted to gain better understanding of the widespread occurrence and distribution of herbicide resistance in Washington.
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Details
- Title
- Acetolactate synthase herbicide resistance in the dryland regions of Eastern Washington
- Creators
- Rachel Jillayane Zuger
- Contributors
- Ian Cristofer Burke (Chair)Drew Lyon (Committee Member) - Washington State University, Crop and Soil Sciences, Department ofRick Allen Boydston (Committee Member)
- 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] :
- Number of pages
- 139
- Identifiers
- 99900525370201842
- Language
- English
- Resource Type
- Thesis