stability.par {agricolae} | R Documentation

## Stability analysis. SHUKLA'S STABILITY VARIANCE AND KANG'S

### Description

This procedure calculates the stability variations as well as the statistics of selection for the yield and the stability. The averages of the genotype through the different environment repetitions are required for the calculations. The mean square error must be calculated from the joint variance analysis.

### Usage

    stability.par(data,rep,MSerror,alpha=0.1,main=NULL,cova = FALSE,name.cov=NULL,
    file.cov=0,console=FALSE)

### Arguments

`data` | matrix of averages, by rows the genotypes and columns the environment
`rep` | Number of repetitions
`MSerror` | Mean Square Error
`alpha` | Label significant
`main` | Title
`cova` | Covariable
`name.cov` | Name covariable
`file.cov` | Data covariable
`console` | logical, print output

### Details

Stable (i) determines the contribution of each genotype to GE interaction by calculating var(i); (ii) assigns ranks to genotypes from highest to lowest yield receiving the rank of 1; (iii) calculates protected LSD for mean yield comparisons; (iv) adjusts yield rank according to LSD (the adjusted rank labeled Y); (v) determines significance of var(i) usign an aproximate F-test; (vi) assigns stability rating (S) as follows: -8, -4 and -2 for var(i) significant at the 0.01, 0.05 and 0.10 probability levels, and 0 for nonsignificant var(i) ( the higher the var(i), the less stable the genotype); (vii) sums adjusted yield rank, Y, and stability rating, S, for each genotype to determine YS(i) statistic; and (viii) calculates mean YS(i) and identifies genotypes (selection) with YS(i) > mean YS(i).

### Value

`analysis` | Analysis of variance
`statistics` | Statistics of the model
`stability` | summary stability analysis

### Author(s)

Felipe de Mendiburu

### References

Kang, M. S. 1993. Simultaneous selection for yield and stability: Consequences for growers. Agron. J. 85:754-757. Manjit S. Kang and Robert Mangari. 1995. Stable: A basic program for calculating stability and yield-stability statistics. Agron. J. 87:276-277

### See Also

`stability.nonpar`

### Examples

    library(agricolae)
    # example 1
    # Experimental data,
    # replication rep= 4
    # Mean square error, MSerror = 1.8
    # 12 environment
    # 17 genotype  = 1,2,3,.., 17
    # yield averages of 13 genotypes in localities
    f <- system.file("external/dataStb.csv", package="agricolae")
    dataStb<-read.csv(f)
    stability.par(dataStb, rep=4, MSerror=1.8, alpha=0.1, main="Genotype",console=TRUE)

    #example 2 covariable. precipitation
    precipitation<- c(1000,1100,1200,1300,1400,1500,1600,1700,1800,1900,2000,2100)
    stability.par(dataStb, rep=4, MSerror=1.8, alpha=0.1, main="Genotype",
     cova=TRUE, name.cov="Precipitation", file.cov=precipitation,console=TRUE)

[Package agricolae version 1.2-9 Index]