gxeStability function

Calculate stability coefficients for genotype-by-environment data

This function calculates different measures of stability, the cultivar-superiority measure of Lin & Binns (1988), Shukla's (1972) stability variance and Wricke's (1962) ecovalence.

gxeStability(
  TD,
  trials = names(TD),
  trait,
  method = c("superiority", "static", "wricke"),
  bestMethod = c("max", "min"),
  sorted = c("descending", "ascending", "none")
)

Arguments

• TD: An object of class TD.
• trials: A character string specifying the trials to be analyzed. If not supplied, all trials are used in the analysis.
• trait: A character string specifying the trait to be analyzed.
• method: A character vector specifying the measures of stability to be calculated. Options are "superiority" (cultivar-superiority measure), "static" (Shukla's stability variance) or "wricke" (wricke's ecovalence).
• bestMethod: A character string specifying the criterion to define the best genotype. Either "max" or "min".
• sorted: A character string specifying the sorting order of the results.

Returns

An object of class stability, a list containing: - superiority: A data.frame containing values for the cultivar-superiority measure of Lin and Binns.

• static: A data.frame containing values for Shukla's stability variance.

• wricke: A data.frame containing values for Wricke's ecovalence.

• trait: A character string indicating the trait that has been analyzed.

Examples

## Compute three stability measures for TDMaize.
geStab <- gxeStability(TD = TDMaize, trait = "yld")

## Summarize results.
summary(geStab)

## Create plot of the computed stability measures against the means.
plot(geStab)

## Create a .pdf report summarizing the stability measures.
report(geStab, outfile = tempfile(fileext = ".pdf"))

## Compute Wricke's ecovalance for TDMaize with minimal values for yield as
## the best values. Sort results in ascending order.
geStab2 <- gxeStability(TD = TDMaize, trait = "yld", method = "wricke",
                       bestMethod = "min", sorted = "ascending")
summary(geStab2)

References

Lin, C. S. and Binns, M. R. 1988. A superiority measure of cultivar performance for cultivar x location data. Can. J. Plant Sci. 68: 193-198

Shukla, G.K. 1972. Some statistical aspects of partitioning genotype-environmental components of variability. Heredity 29:237-245

Wricke, G. Uber eine method zur erfassung der okologischen streubreit in feldversuchen. Zeitschrift für Pflanzenzucht, v. 47, p. 92-96, 1962

See Also

Other stability: plot.stability(), report.stability()