Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Golden, Bobby R.

Committee Member

Bond, Jason A.

Committee Member

Bararpour, M. T.

Committee Member

Gore, Jeffrey

Committee Member

Dodds, Darrin M.

Date of Degree

12-13-2019

Original embargo terms

Worldwide

Document Type

Dissertation - Open Access

Major

Agronomy

Degree Name

Doctor of Philosophy

College

College of Agriculture and Life Sciences

Department

Department of Plant and Soil Sciences

Abstract

Research was conducted at the Mississippi State University Delta Research and Extension Center from 2016 to 2018 to determine the effects of sub-lethal concentrations of paraquat, glyphosate, saflufenacil, and sodium chlorate exposure to rice at late-season growth stages, determine the effects of exposure to sub-lethal concentrations of glyphosate or paraquat on multiple rice cultivars, and characterize the effects of paraquat exposure and Oebalus pugnax feeding on rice grain quality. In the current research, rough rice grain yields were reduced by exposure to sub-lethal concentrations of soybean desiccants 0 to 28 DAH. Rice injury was determined to not be an accurate predictor of rough rice grain yield loss as injury did not exceed 20% with any desiccant, and no injury was observed from glyphosate applications. Rough rice grain yield reductions were reflected in yield component reductions following desiccant exposure. Applications of sub-lethal concentrations of glyphosate or paraquat to rice at 50% heading caused rough rice grain yield decreases ranging from 0 to 20 and 9 to 21 % respectively. Hybrid cultivars were unaffected following glyphosate exposure at 50% heading. In the current research, observations of paraquat exposure or O. pugnax infestation of rice at the soft dough growth stage suggest rice may exhibit severe sensitivity to both events in the form of reduced kernel weight and reductions in rice milling quality. Rough rice grain yield reductions coupled with milling quality reductions and driven by the proximity of rice to corn, cotton, soybean, and sorghum in Mississippi creates the need to exercise caution when applying desiccants.

URI

https://hdl.handle.net/11668/16413

Sponsorship

Mississippi Rice Promotion Board

Comments

Rice||off-target movement||drift||desiccant||paraquat||glyphosate||sub-lethal

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