Friday, 6 January 2006 - 10:45 AM

Assessment of Field Tolerance to Root-knot Nematodes in Eight Cotton Cultivars

Gus Wilson1, J.D. Barham2, R.J. Bateman2, and T.L. Kirkpatrick2. (1) Arkansas Cooperative Extension Service, Ashley County Extension Office, 205 East Jefferson, Hamburg, AR 71646, (2) University of Arkansas, Southwest Research and Extension Center, 362 Highway 174 North, Hope, AR 71801

The root-knot nematode, Meloidogyne incognita, is the most widespread economic nematode of cotton in the U.S. This nematode is found throughout the Cotton Belt and is responsible for more yield suppression beltwide than the other economic species combined. Currently, there are no commercially available cotton cultivars with genetic resistance to root-knot that are adapted to the mid-South or the southeastern portion of the Cotton Belt. In the absence of true resistance to the nematode, cultivar tolerance levels to the nematode may be important. Tolerance, as used here, is defined as the ability of a cultivar to grow and maintain acceptable yield while supporting a population of M. incognita that would cause growth retardation and yield suppression in a susceptible cultivar. A field trial was conducted in Ashley Co., AR in 2005 to assess the tolerance levels of eight commercial cotton cultivars. The experiment was conducted in a field with a history of cotton monoculture and a severe root-knot problem. Experimental design was a paired plot with main plots either receiving soil fumigation with 1,3 dichloropropene (Telone II) at 3 gallons per acre preplant or not receiving the fumigant. Subplots were the eight cultivars. Plant growth and development as well as yield were evaluated. Nematode population densities, associated with each cultivar with and without Telone II, and root galling severity were also measured. Results, as well as the potential role of tolerance to nematodes in cotton cultivars, will be discussed.

See more of Cotton Disease Council - Mid - Morning Session
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See more of The Beltwide Cotton Conferences, January 3-6 2006