EV.AMMI {ammistability} | R Documentation |

`EV.AMMI`

computes the Sums of the Averages of the Squared Eigenvector
Values (EV) (Zobel 1994) considering all
significant interaction principal components (IPCs) in the AMMI model. Using
EV, the Simultaneous Selection Index for Yield and Stability (SSI) is also
calculated according to the argument `ssi.method`

.

EV.AMMI(model, n, alpha = 0.05, ssi.method = c("farshadfar", "rao"), a = 1)

`model` |
The AMMI model (An object of class |

`n` |
The number of principal components to be considered for computation. The default value is the number of significant IPCs. |

`alpha` |
Type I error probability (Significance level) to be considered to identify the number of significant IPCs. |

`ssi.method` |
The method for the computation of simultaneous selection
index. Either |

`a` |
The ratio of the weights given to the stability components for
computation of SSI when |

The Averages of the Squared Eigenvector Values (\(EV\)) (Zobel 1994) is computed as follows:

\[EV = \sum_{n=1}^{N'}\frac{\gamma_{in}^2}{N'}\]Where, \(N'\) is the number of significant IPCs (number of IPC that were retained in the AMMI model via F tests); and \(\gamma_{in}\) is the eigenvector value for \(i\)th genotype.

A data frame with the following columns:

`EV` |
The EV values. |

`SSI` |
The computed values of simultaneous selection index for yield and stability. |

`rEV` |
The ranks of EV values. |

`rY` |
The ranks of the mean yield of genotypes. |

`means` |
The mean yield of the genotypes. |

The names of the genotypes are indicated as the row names of the data frame.

Zobel RW (1994).
“Stress resistance and root systems.”
In *Proceedings of the Workshop on Adaptation of Plants to Soil Stress. 1-4 August, 1993. INTSORMIL Publication 94-2*, 80–99.
Institute of Agriculture and Natural Resources, University of Nebraska-Lincoln.

library(agricolae) data(plrv) # AMMI model model <- with(plrv, AMMI(Locality, Genotype, Rep, Yield, console = FALSE)) # ANOVA model$ANOVA # IPC F test model$analysis # Mean yield and IPC scores model$biplot # G*E matrix (deviations from mean) array(model$genXenv, dim(model$genXenv), dimnames(model$genXenv)) # With default n (N') and default ssi.method (farshadfar) EV.AMMI(model) # With n = 4 and default ssi.method (farshadfar) EV.AMMI(model, n = 4) # With default n (N') and ssi.method = "rao" EV.AMMI(model, ssi.method = "rao") # Changing the ratio of weights for Rao's SSI EV.AMMI(model, ssi.method = "rao", a = 0.43)

[Package *ammistability* version 0.1.2 Index]