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Cotton response to over-the-top trifloxysulfuron sodium applications
Abstract
Envoke® (common name: trifloxysulfuron sodium), is a new sulfonylurea herbicide developed by Syngenta for over-the-top application to cotton. A two-year study was conducted with concurrent field and greenhouse experiments to determine the innate resistance of cotton to Envoke® alone and tank-mixed with Touchdown IQ (glyphosate). Field study treatments were as follows: Untreated check; Envoke® at 5.3, 7.9, and 15.8 g ai ha⁻¹; Envoke® at 5.3 and 7.9 g ai ha⁻¹ tank-mixed with Touchdown IQ at 840 g ai ha⁻¹; Envoke® ; Touchdown IQ at 840 g ai ha⁻¹; Staple (pyrithiobac) at 6.72 g ha⁻¹ tank-mixed with glyphosate at 840 g ai ha⁻¹. Stoneville 4892 BR and Delta and Pine Land 451 B/RR, were investigated under field conditions for their response to Envoke® application. Envoke® application at the labeled rate (5.3 g ai ha⁻¹) did not significantly impact yields in any of the experiments, but did result in a transient chlorosis that was completely dissipated by 30 days after treatment (DAT). Treatments of Envoke® tank-mixed with Touchdown IQ or with Envoke® at 15.8 g ai ha⁻¹ showed much more severe injury persistence, height reduction, a reduction in leaf area and lower dry weight accumulation at both 7 and 14 DAT. Regardless of their severity, the response of cotton to Envoke® application was inconsequential to yield quantity or quality. Application timings at the 1-, 3- and 6-leaf stage of development were compared in a greenhouse study. The net assimilation of carbon dioxide of single leaves was measured with a Li-Cor 6400 portable photosynthetic meter. The 1-leaf application timing resulted in the most severe chlorosis, stunting and occasional necrosis. The 6-leaf application timing had the most rapid period of recovery from the visual symptoms. Net photosynthetic rate corresponded well with the visual injury ratings observed in the greenhouse. Net photosynthetic ratings did not provide a stress indicator prior to the onset of visual injury, but it was determined that the net rate of photosynthesis recovered by 14 DAT when there was still significant visual injury. None of the treatments at any application time resulted in an impact on the timing of reproductive maturity.
Description
Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item.Includes bibliographical references (leaves 58-59).
Issued also on microfiche from Lange Micrographics.
Subject
molecular and environmental plant sciences.Major molecular and environmental plant sciences.
Collections
Citation
Hoffman, Steven Matthew,1978- (2003). Cotton response to over-the-top trifloxysulfuron sodium applications. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /ETD -TAMU -2003 -THESIS -H63.
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