MATMODEL Version 3.0 provides open source software for AMMI and related analyses of agricultural yield-trial data. The data comprise a two-way factorial design with a number of genotypes tested in a number of environments, with or without replication. The Additive Main effects and Multiplicative Interaction (AMMI) model combines analysis of variance (AOV) to partition the genotype main effects, environment main effects, and genotype-by-environment (GE) interaction effects, followed by principal component analysis (PCA) to partition the GE interaction into several components. The two main purposes of AMMI analysis are: (1) to understand complex GE interactions, including delineating mega-environments and (2) to gain accuracy by separating a signal-rich parsimonious AMMI model from a discarded noise-rich residual.
Click below to download a zip file of about 1 megabyte that produces 21 files. I recommend placing these files in the subdirectory C:\MM30 although you are free to make other choices.
MATMODEL operates from a DOS prompt. It offers many advanced AMMI features that would be difficult to implement in general-purpose statistical packages, including imputing missing values and mega-environment analysis. However, the graphs are rough, so machine-readable versions of the output can be produced to facilitate importing AMMI parameters into graphics software for publication quality graphs.
Begin by printing a copy of the file MM30.DOC, the program documentation of about 60 pages in MS Word format. This explains both AMMI analysis and MATMODEL use. The additional 20 files include the executable program and its FORTRAN source code, as well as many sample input and output files that are explained by the program documentation. MATMODEL is free software that you may redistribute and/or modify under the terms of the GNU General Public License as published by the Free Software Foundation.
Download MATMODEL 3.0
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