Quantifying Potential Tolerance of Selected Cotton Cultivars to Belonolaimus longicaudatus.
Glyphosate-tolerant cotton cultivars were evaluated for tolerance to Belonolaimus longicaudatus in field experiments conducted from 2004 to 2005. Field trials were arranged in a split-plot design that included treatment with four levels of 1, 3-dichloropropene (0.0, 13.9, 27.8, and 41.7 1 a.i./ha) to establish a range of population densities of B. longicaudatus. Six cotton cultivars (early-to-mid maturity: DP444BG/RR SG501BR, ST5242BR; mid-to late maturity: DP451B/RR, ST5599BR, DP655BRR) were planted as whole plots. Fumigation was effective in suppressing B. longicaudatus population densities at mid-season, but not at cotton harvest, and increased cotton lint yield. The cultivar x fumigation interaction for cotton lint yield was not significant for the six cultivars evaluated, indicating that tolerance did not occur in this nematode-host combination. Early-to-mid maturity cultivars yielded significantly more than mid-to-late maturity cultivars in both years. Small but significant differences in nematode final population density were observed between cultivars that may be related to relative maturity.
Koenning
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Research Assistant Professor, Department of Plant Pathology, NC State University, Raleigh, NC 27695-7616 Professor, Crop Science Department, NC State University, Raleigh, NC 27695-7620 Regional Agronomist, Agronomic Division, North Carolina Department of Agriculture and Consumer Services, 3184 Old NC 41, Bladenboro, NC 28320.
Bowman
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Morris
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