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Ecology and Epidemiology

Quantitative Relationships Between Sweet Corn Yield and Common Rust, Puccinia sorghi. J. K. Pataky, Assistant professor, Department of Plant Pathology, University of Illinois, Urbana 61801; Phytopathology 77:1066-1071. Accepted for publication 22 January 1987. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/Phyto-77-1066.

The quantitative relationships between sweet corn yield and common rust (Puccinia sorghi) were studied for three hybrids, Florida Staysweet, Gold Cup, and Stylepak, in 1984, 1985, and 1986. Variation in sweet corn yield was best explained by regression models in which the independent variable was rust severity assessed approximately 1 wk before harvest. The effects of rust on primary and secondary ears varied by hybrid and environment partly due to the number of secondary ears produced by a hybrid in an environment. General models were derived over environments for total ear weight (Florida Staysweet and Stylepak) and for total number of marketable ears (Florida Staysweet and Gold Cup). These models estimated that yield reduction due to rust was 6% of the maximum total ear weight and 6.5% of the maximum total number of marketable ears for each 10% rust severity.