VIEW ARTICLE

Ecology and Epidemiology

Analysis and Comparison of Fusiform Rust Disease Progress Curves for Five Slash Pine Familes. M. M. Griggs, Geneticist, Southern Forest Experiment Station-U.S. Dep. Agric., Forest Service, Gulfport, MS 39503; W. L. Nance(2), and R. J. Dinus(3). (2)(3)Plant Geneticist, and former Principal Plant Geneticist, Southern Forest Experiment Station-U.S. Dep. Agric., Forest Service, Gulfport, MS 39503. Phytopathology 68:1631-1636. Accepted for publication 17 May 1978. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1978.. DOI: 10.1094/Phyto-68-1631.

Disease progress curves were employed to quantify genetic variation in fusiform rust (caused by Cronartium fusiforme) resistance among five half-sib slash pine families planted at two locations. A growth analysis procedure was adopted whereby disease progress curves for each family were smoothed by fitting polynomials in time to cumulative percent infection. Then the coefficients for each polynomial fit were subjected to univariate and multivariate analyses of variance. Family effects were strong and statistically significant; location and location × family effects were identifiable but not statistically significant. Three distinct categories of disease progress curves were found: resistant, intermediate, and susceptible. Methods are advanced to quantify and evaluate the importance of factors that affect disease progress in fusiform rust and other plant diseases.