variance of rank

variance_of_rank calculate variance of a genotype across environments.

variance_of_rank(data, trait, genotype, environment, 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

environment

colname of a column containing a character or factor vector labeling different environments

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.#'

Value

a data table with variance of rank

Details

Variance of rank (Nassar and Huehn, 1987) is calculatd based on regression function. Variety with low variance of rank is considered as stable. Equation of variance of rank can be found in vignette file.

References

Nassar R, H昼㹣hn M (1987). “Studies on estimation of phenotypic stability: Tests of significance for nonparametric measures of phenotypic stability.” Biometrics, 43(1), 45--53. ISSN 0006-341X.

Author

Tien-Cheng Wang

Examples

data(Data)
variance.of.rank <- variance_of_rank(
 data = Data,
 trait = "Yield",
 genotype = "Genotype",
 environment = "Environment",
 unit.correct = FALSE)