AMMI {statforbiology} | R Documentation |
AMMI analysis for multienvironment genotype experiments
Description
This function performs the AMMI (Addittive Main effects Multiplicative Interaction) analysis, according to Zobel et al (1988). The function has been described in Onofri and Ciriciofolo (2007).
Usage
AMMI(yield, genotype, environment, block = NULL, PC = 2,
MSE = NULL, dfr = NULL)
Arguments
yield |
a vector containing yield levels |
genotype |
a vector containing genotype codings |
environment |
a vector containing environment codings |
block |
a vector containing block codes for each environment |
PC |
the number of PCs that one wants to extract |
MSE |
Mean Squared Error |
dfr |
Residual Degrees of Freedom |
Value
Returns a list of class 'AMMIobject' with the following components
genotype_means |
The overall least squares genotype means |
environment_means |
The overall least squares environment means |
interaction_means |
The least squares means for the genotype by environment combinations |
interaction_effect |
a two-way table of interaction effects |
additive_ANOVA |
an ANOVA table for the additive model |
mult_Interaction |
an ANOVA table for multiplicative model |
MSE |
Mean Square Error |
dfr |
Degrees of freedom for the MSE |
environment_scores |
a table of environment scores |
genotype_scores |
a table of genotype scores |
stability |
AMMI stability value (ASV; Mohammadi and Amri, 2008) |
Author(s)
Andrea Onofri
References
Mohammadi, R., Amri, A., 2008. Comparison of parametric and non-parametric methods for selecting stable and adapted durum wheat genotypes in varibale environments. Euphytica 159, 419–432.
Onofri, A., Ciriciofolo, E., 2007. Using R to perform the AMMI analysis on agriculture variety trials. R NEWS 7, 14–19.
Zobel, R. W., Wright, M.J., and Gauch, H. G., 1988. Statistical analysis of a yield trial. Agronomy Journal, 388-393.
Examples
WinterWheat <- getAgroData("WinterWheat")
tab <- with(WinterWheat, AMMI(Yield, Genotype, Year, Block, PC = 2))
tab