Theses and Dissertations

Advisor

Bond, Jason

Committee Member

Golden, Bobby

Committee Member

Gholson, Drew

Committee Member

Bowman, Hunter

Committee Member

Allen, Thomas, Jr.

Date of Degree

8-7-2025

Original embargo terms

Immediate Worldwide Access

Document Type

Dissertation - Open Access

Major

Agronomy

Degree Name

Doctor of Philosophy (Ph.D.)

College

College of Agriculture and Life Sciences

Department

Department of Plant and Soil Sciences

Abstract

A new non-transgenic rice has been developed called ROXY, which is resistant to formulations of oxyfluorfen. Utilizing the ROXY rice production system in a furrow-irrigated system could help combat troublesome terrestrial weeds and be a viable option for producers. To evaluate the performance of oxyfluorfen in furrow-irrigated ROXY rice production system, two concurrent field studies were conducted at the Delta Research and Extension Center in Stoneville, MS, from 2022 to 2024. The first study evaluated residual grass and broadleaf weed control with oxyfluorfen applied delayed-preemergence (DPRE). Factor A was oxyfluorfen rates of 0, 700, and 981 g ai ha-1. Factor B was herbicide mixture and included no mixture, clomazone at 560 g ai ha-1, saflufenacil at 50 g ai ha-1, and halosulfuron-methyl plus prosulfuron at 83 g ai ha-1. The second study evaluated residual grass and broadleaf weed control with oxyfluorfen in a full-season herbicide program for furrow-irrigated rice. Factor A was DPRE treatment and included no DPRE treatment, oxyfluorfen at 1,121 g ha-1, oxyfluorfen 1,121 g ha-1 plus clomazone at 560 g ha-1, and clomazone at 560 g ha-1 plus saflufenacil at 50 g ha-1. Factor B was early postemergence (EPOST) treatment and included no EPOST, and propanil plus thiobencarb at 6,728 g ai ha-1 applied at the two- to three-leaf rice stage. Factor C was late postemergence (LPOST) and included no LPOST, and quinclorac at 421 g ai ha-1 plus halosulfuron plus prosulfuron at 83 g ha-1 plus petroleum oil surfactant at 1% (v/v) at the four-leaf to one-tiller rice stage. When oxyfluorfen was mixed with clomazone, saflufenacil, or halosulfuron plus prosulfuron, barnyardgrass control was ≥ 78%. Oxyfluorfen at 981 g ha alone resulted in greater barnyardgrass and Palmer amaranth control 35 DAA than oxyfluorfen at 700 g ha. In the second study, barnyardgrass control 42 DAA never exceeded 89%. Oxyfluorfen, oxyfluorfen plus clomazone, and clomazone plus saflufenacil DPRE alone all provided comparable Palmer amaranth control 42 DAA. Oxyfluorfen-tolerant rice represents a viable option to be used in furrow-irrigated rice when combined with overlapping residual herbicides but will not be able to provide adequate control alone.

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