Shukla's stability variance parameter

The function computes the Shukla's stability variance parameter (1972) and uses the Kang's nonparametric stability (rank sum) to imcorporate the mean performance and stability into a single selection criteria.

Usage

Shukla(.data, env, gen, rep, resp, verbose = TRUE)

Arguments

.data: The dataset containing the columns related to Environments, Genotypes, replication/block and response variable(s).
env: The name of the column that contains the levels of the environments.
gen: The name of the column that contains the levels of the genotypes.
rep: The name of the column that contains the levels of the replications/blocks.
resp: The response variable(s). To analyze multiple variables in a single procedure use, for example, resp = c(var1, var2, var3).
verbose: Logical argument. If verbose = FALSE the code will run silently.

Value

An object of class Shukla, which is a list containing the results for each variable used in the argument resp. For each variable, a tibble with the following columns is returned.

GEN the genotype's code.
Y the mean for the response variable.
ShuklaVar The Shukla's stability variance parameter.
rMean The rank for Y (decreasing).
rShukaVar The rank for ShukaVar.
ssiShukaVar The simultaneous selection index (\(ssiShukaVar = rMean + rShukaVar\)).

References

Shukla, G.K. 1972. Some statistical aspects of partitioning genotype-environmental components of variability. Heredity. 29:238-245. doi:10.1038/hdy.1972.87

Kang, M.S., and H.N. Pham. 1991. Simultaneous Selection for High Yielding and Stable Crop Genotypes. Agron. J. 83:161. doi:10.2134/agronj1991.00021962008300010037x

Author

Tiago Olivoto tiagoolivoto@gmail.com

Examples

# \donttest{
library(metan)
out <- Shukla(data_ge2,
             env = ENV,
             gen = GEN,
             rep = REP,
             resp = PH)
#> Evaluating trait PH |============================================| 100% 00:00:00 

# }