Cotton Cultivars Evaluated for Tolerance to Reniform Nematode

Abstract

Thirty-nine commercial cotton (Gossypium hirsutum) cultivars were evaluated to identify those with tolerance to reniform nematode (Rotylenchulus reniformis). Trials were conducted for three years at two west-central Mississippi field locations naturally infested with reniform nematode. Main plots were cultivars and subplots were either not treated or treated with nematicide. Reniform nematode soil population densities were assessed throughout the growing season. At harvest, seed cotton yields were determined, and fiber quality was evaluated for select samples. Data were pooled from all years and locations, and t-tests were used to identify tolerant cultivars. Cultivars were judged tolerant if nematicide did not improve yield, although the nematode population was reduced at a midseason sampling interval. Only Deltapine 449 BR, Paymaster 1218 BR, and Suregrow 215 BR met these criteria. Additionally, tolerance indices were calculated for nine cultivars showing suppressed nematode populations in nematicide-treated plots at any point during the growing season. The three tolerant cultivars identified based on the t-tests ranked first (Suregrow 215 BR), second (Paymaster 1218 BR), and fifth (Deltapine 449 BR) with respect to tolerance index. Because they do not appear to suffer significant yield loss due to reniform nematode, these three cultivars may benefit growers.Accepted for publication 12 January 2009. Published 12 March 2009.The primary objective of this project was to evaluate commercial cotton cultivars for tolerance to the reniform nematode in west-central Mississippi. Additionally, qualitative fiber properties were assessed to evaluate whether or not they varied due to nematode pressure. Thirty-nine commercial cotton cultivars were evaluated to identify those with tolerance to reniform nematode. Trials were conducted for three years at two west-central Mississippi field locations naturally infested with reniform nematode.