MASV.AMMI | R Documentation |
MASV.AMMI
computes the Modified AMMI Stability Value (MASV)
\insertCitezali_evaluation_2012,ajay_rectification_2019ammistability
(Please see Note) from a modified formula of AMMI Stability Value
(ASV) \insertCitepurchase_parametric_1997ammistability. 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
. \loadmathjax
MASV.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 Modified AMMI Stability Value (\mjseqnMASV) \insertCiteajay_rectification_2019ammistability is computed as follows:
\mjsdeqnMASV = \sqrt\sum_n=1^N'-1\left (\fracSSIPC_nSSIPC_n+1 \times PC_n \right )^2 + \left (PC_N' \right )^2
Where, \mjseqnSSIPC_1, \mjseqnSSIPC_2, \mjseqn\cdots, \mjseqnSSIPC_n are the sum of squares of the 1st, 2nd, ..., and \mjseqnnth IPC; and \mjseqnPC_1, \mjseqnPC_2, \mjseqn\cdots, \mjseqnPC_n are the scores of 1st, 2nd, ..., and \mjseqnnth IPC.
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 \insertCitezali_evaluation_2012;textualammistability, the formula for both AMMI stability value (ASV) was found to be erroneous, when compared with the original publications \insertCitepurchase_parametric_1997,purchase_use_1999,purchase_genotype_2000ammistability.
ASV \insertCitezali_evaluation_2012ammistability \mjsdeqnASV = \sqrt\left ( \fracSSIPC_1SSIPC_2 \right ) \times (PC_1)^2 + \left (PC_2 \right )^2
ASV \insertCitepurchase_parametric_1997,purchase_use_1999,purchase_genotype_2000ammistability \mjsdeqnASV = \sqrt\left (\fracSSIPC_1SSIPC_2 \times PC_1 \right )^2 + \left (PC_2 \right )^2
The authors believe that the proposed Modified AMMI stability value (MASV)
in \insertCitezali_evaluation_2012;textualammistability is also
erroneous and have implemented the corrected one in MASV.AMMI
\insertCiteajay_rectification_2019ammistability.
MASV \insertCitezali_evaluation_2012ammistability \mjsdeqnMASV = \sqrt\sum_n=1^N'-1\left ( \fracSSIPC_nSSIPC_n+1 \right ) \times (PC_n)^2 + \left (PC_N' \right )^2
AMMI
, index.AMMI
,
SSI
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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