environmental_variance {toolStability}

Environmental variance

Description

environmental_variance is used to calculate variance of a genotype across environments.

Usage

environmental_variance(data, trait, genotype, unit.correct = FALSE)

Arguments

data

a dataframe containing trait, genotype and environment.

trait

colname of a column containing a numeric vector of interested trait to be analysized.

genotype

colname of a column containing a character or factor vector labeling different genotypic varieties

unit.correct

logical, default is FALSE, returning the stability index with unit equals to squared unit of trait; when TRUE, returning stability index with the unit as same as unit of trait.'

Details

Environmental variance (Roemer, 1917) is calculated by squared and suming up all deviation from genotypic mean for each genotype. The larger the environmental variance of one genotype is, the lower the stability. Equation of environmental variance can be found in vignette file.

Value

a data table with environmental variance

Author(s)

Tien-Cheng Wang

References

Römer T (1917). “Sind die ertragdreichen Sorten ertagissicherer?” Mitteilungen der Deutschen Landwirtschaftlichen Gesellschaft, 32(1), 87–89.

Examples

data(Data)
environmental.variance <- environmental_variance(
 data = Data,
 trait = "Yield",
 genotype = "Genotype",
 unit.correct = FALSE)