Description Usage Arguments Details Value Note References See Also Examples

`MASV.AMMI`

computes the Modified AMMI Stability Value (MASV) (Zali et
al., 2012; Ajay et al., 2019; Please see **Note**) from a modified formula of AMMI
Stability Value (ASV) (Purchase et al. 1997). This formula calculates AMMI
stability value considering all significant interaction principal components
(IPCs) in the AMMI model. Using MASV, the Simultaneous Selection Index for
Yield and Stability (SSI) is also calculated according to the argument
`ssi.method`

.

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 Modified AMMI Stability Value
(*MASV*) is computed as follows (Ajay
et al., 2019):

*MASV =
√[∑ ^{N'-1}_{n=1}((^{SSIPCn} ⁄
_{SSIPCn+1}) × PC_{1})^{2} +
(PC_{N'})^{2}]*

Where, *SSIPC _{1}*,

A data frame with the following columns:

`MASV` |
The MASV values. |

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

`rMASV` |
The ranks of MASV 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.

In Zali et al., (2012), the formula for both AMMI stability value (ASV) was found to be erroneous, when compared with the original publications (Purchase 1997; Purchase et al., 1999; Purchase et al., 2000).

**ASV (Zali et al., 2012)**

*ASV = √[( ^{SSIPC1}
_{⁄ SSIPC2}) × (PC_{1})^{2}
+ (PC_{2})^{2}]*

**ASV (Purchase 1997; Purchase et al., 1999; Purchase et al., 2000)**

*ASV =
√[(( ^{SSIPC1} ⁄
_{SSIPC2}) × PC_{1})^{2} +
(PC_{2})^{2}]*

The authors believe that the proposed Modified AMMI stability value (MASV)
in Zali et al., (2012) is also erroneous and have implemented the corrected
one in `MASV.AMMI`

(Ajay et al., 2019).

**MASV (Zali et al., 2012)**

*MASV = √[∑ ^{N'-1}_{n=1}(^{SSIPCn} ⁄
_{SSIPCn+1}) × (PC_{1})^{2} +
(PC_{N'})^{2}]*

purchase_parametric_1997ammistability

\insertRefpurchase_use_1999ammistability

\insertRefpurchase_genotype_2000ammistability

\insertRefzali_evaluation_2012ammistability

\insertRefajay_rectification_2019ammistability

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | ```
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)
MASV.AMMI(model)
# With n = 4 and default ssi.method (farshadfar)
MASV.AMMI(model, n = 4)
# With default n (N') and ssi.method = "rao"
MASV.AMMI(model, ssi.method = "rao")
# Changing the ratio of weights for Rao's SSI
MASV.AMMI(model, ssi.method = "rao", a = 0.43)
``` |

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