title: Multivariate mixed linear model analysis of longitudinal data: an information-rich statistical technique for analyzing plant disease resistance.
abstract: ABSTRACT   The mixed linear model (MLM) is an advanced statistical technique applicable to many fields of science. The multivariate MLM can be used to model longitudinal data, such as repeated ratings of disease resistance taken across time. In this study, using an example data set from a multi-environment trial of northern leaf blight disease on 290 maize lines with diverse levels of resistance, multivariate MLM analysis was performed and its utility was examined. In the population and environments tested, genotypic effects were highly correlated across disease ratings and followed an autoregressive pattern of correlation decay. Because longitudinal data are often converted to the univariate measure of area under the disease progress curve (AUDPC), comparisons between univariate MLM analysis of AUDPC and multivariate MLM analysis of longitudinal data were made. Univariate analysis had the advantage of simplicity and reduced computational demand, whereas multivariate analysis enabled a comprehensive perspective on disease development, providing the opportunity for unique insights into disease resistance. To aid in the application of multivariate MLM analysis of longitudinal data on disease resistance, annotated program syntax for model fitting is provided for the software ASReml.
authors.affiliation: Department of Plant and Soil Sciences, University of Delaware, Newark 19716, USA.
authors.forename: Yogasudha
authors.initials: Y
authors.lastname: Veturi
authors.forename: Kristen
authors.initials: K
authors.lastname: Kump
authors.forename: Ellie
authors.initials: E
authors.lastname: Walsh
authors.forename: Oliver
authors.initials: O
authors.lastname: Ott
authors.forename: Jesse
authors.initials: J
authors.lastname: Poland
authors.forename: Judith M
authors.initials: JM
authors.lastname: Kolkman
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Balint-Kurti
authors.forename: James B
authors.initials: JB
authors.lastname: Holland
authors.forename: Randall J
authors.initials: RJ
authors.lastname: Wisser
mesh_terms: D001203:Ascomycota / Q000276:immunology* / Q000502:physiology; D003198:Computer Simulation; D003627:Data Interpretation, Statistical; D060467:Disease Resistance; D005838:Genotype; D016014:Linear Models; D008137:Longitudinal Studies; D015999:Multivariate Analysis; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D012107:Research Design; D012984:Software; D003313:Zea mays / Q000276:immunology* / Q000382:microbiology