Shukla function

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.

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.

Returns

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 ($ssiShukaVar = rMean + rShukaVar$).

Examples

library(metan)
out <- Shukla(data_ge2,
             env = ENV,
             gen = GEN,
             rep = REP,
             resp = PH)

References

Shukla, G.K. 1972. Some statistical aspects of partitioning genotype-environmental components of variability. Heredity. 29:238-245. tools:::Rd_expr_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. tools:::Rd_expr_doi("10.2134/agronj1991.00021962008300010037x")

Author(s)

Tiago Olivoto tiagoolivoto@gmail.com