Submitted to: Cotton Research and Extension Report
Publication Type: Experiment Station
Publication Acceptance Date: March 1, 2003
Publication Date: April 1, 2003
Citation: Davis, R.F., Earl, H.J., Timper, P. 2003. Interaction of root-knot nematode stress and water stress in cotton. 2002 University of Georgia Cotton Research and Extension Report. p.312-315. Technical Abstract: Drip irrigation was used in a field with a loamy sand naturally infested with Meloidogyne incognita to create low, medium and high levels of drought stress, though rainfall minimized drought stress early in the season. Fumigation with 1,3-dichloropropene (0 or 56 l/ha) was used to create a range of nematode densities. Three meters of each plot were hand harvested and ginned to provide lint and seed yield. A subsample of lint was analyzed for fiber quality, including fiber length and micronaire. Covariance analysis was used to determine within each level of drought stress the relationship between nematode densities at mid-season and seed weight, lint weight, fiber length, and micronaire at harvest. For all levels of drought stress, seed weight (P=0.03), lint weight (P=0.05), and fiber length (P=0.07) decreased and micronaire (P=0.02) increased as nematode populations increased. For seed weight and micronaire, the relationships with nematode densities were similar (alpha=0.10) among the three levels of drought stress (similar slopes and intercepts), but only slope was similar for length. The decrease in lint weight with increasing nematode densities was greater (P=0.07) at the high level of drought stress than at the lower levels of stress.