Monday, November 5, 2007
37-6
Development of a Yield Loss Prediction Model for Asian Soybean Rust: An Update.
Joe Omielan1, James E. Board2, Elena Prior1, Claudia V. Godoy3, and Saratha Kumudini1. (1) University of Kentucky, UK Plant & Soil Sciences, 1405 Veterans Drive, Lexington, KY 40546-0312, (2) Louisiana State University Agricultural Center, Rm. 104 Sturgis Hall, Department of Agronomy & Environmental Mgmt, Baton Rouge, LA 70803, (3) Embrapa - Soja, Rodovia Carlos Joao Strass, Caixa Postal 231, Londrina - PR, Brazil
Soybean rust (SBR) causes accelerated defoliation and leaf injury. The impact of SBR on yield depends on the extent of the injury to the leaf and leaf defoliation, as well as the growth stage when the disease first occurred. The objective of this study was to develop a yield loss prediction model for SBR that was based on leaf area duration and stage of reproductive development. Trials were planted in Kentucky and Louisiana using Group III, IV, and V cultivars. Disease stress was simulated by manual defoliation of 33%, 66%, or 100% of the canopy at weekly intervals starting at one week after R5. Yield loss was related to leaf area duration and dependent on the growth stage at which the accelerated defoliation occurred. The relationship between severity of leaf defoliation, growth stage at which the defoliation occurred and yield seemed fairly consistent across the cultivars and MGs tested in KY and LA.