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ARS Home » Southeast Area » Florence, South Carolina » Coastal Plain Soil, Water and Plant Conservation Research » Research » Publications at this Location » Publication #98159
Title: PERFORMANCE OF ROUNDUP READY COTTON CULTIVARS UNDER THREE HERBICIDE SYSTEMS

Author
item May Iii, Oscar
item MURDOCK, E - CLEMSON UNIVERSITY
item FOWLER, J - CLEMSON UNIVERSITY
item STAPLES, J - CLEMSON UNIVERSITY

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Abstract Only
Publication Acceptance Date: 1/25/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Roundup Ready cultivars have expanded grower options for weed control, but have also complicated Official Cultivar Trials. In Official Cultivar Trials it is not feasible to evaluate Roundup Ready cultivars in a Roundup Ultra herbicide system along with non-transgenic cultivars in a standard herbicide system. Evaluation of Roundup Ready cultivars along with non-transgenic cultivars in a standard herbicide system has raised concern about the validity of yield data from Official Cultivar Trials. To address this issue, we conducted two trials in 1998 that evaluated early and later-maturing Roundup Ready cultivars in three herbicide systems. The cultivars included all those entered into the South Carolina Official Cultivar Trials for 1998. The three herbicide systems included a standard system utilizing soil-applied herbicides and a layby treatment with postemergence and residual activity, and two Roundup Ultra systems with and dwithout residual herbicides. The treatment design was a strip-plot with cultivar the horizontal factor and herbicide system the vertical factor. Three replicates were arranged in randomized complete blocks. The herbicide system x cultivar interaction for lint yield was highly non-significant (P>0.5) in the early and later maturity trials. There was a highly significant (P<0.01) herbicide system main effect, with the highest yields produced in the Roundup Ultra only herbicide system and lowest yields in the standard herbicide system. Cultivar main effects were non-significant in both trials. The lack of a herbicide system x cultivar interaction suggests that yield data from Official Cultivar Trials can be used to select a Roundup Ready cultivar.