Theses and Dissertations

Advisor

Avila, Luis

Committee Member

Tseng, Te-Ming

Committee Member

Bararpour, Taghi

Committee Member

Bond, Jason

Committee Member

Shanmugam, Shankar; Burgos, Nilda

Date of Degree

8-12-2026

Original embargo terms

Immediate Worldwide Access

Document Type

Graduate Thesis - Open Access

Major

Plant & Soil Sciences (Weed Science)

Degree Name

Master of Science (M.S.)

College

College of Agriculture and Life Sciences

Department

Department of Plant and Soil Sciences

Abstract

Palmer amaranth (Amaranthus palmeri S. Watson) is one of the most troublesome herbicide-resistant weeds in U.S. agriculture. This study evaluated (1) seed persistence across soils collected from major row-crop production areas in Mississippi by investigating the influence of soil physicochemical and microbial properties on seed viability and (2) the prevalence of resistance to S-metolachlor and glufosinate among Mississippi populations. A seed burial experiment using soils from 57 locations representing 10 counties showed that seed viability declined substantially between 4 and 6 months after burial. Although soil physicochemical properties were associated with variation in seed viability, no single factor consistently explained persistence, and microbial functional diversity was a weak predictor of seed viability. Herbicide evaluations showed consistently high control with glufosinate and greater variability in responses to S-metolachlor; however, no confirmed resistance to either herbicide was detected. These findings support integrated management practices that reduce seedbank replenishment while preserving herbicide efficacy through continued resistance monitoring.

Sponsorship (Optional)

Cotton Incorporated

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