# ge_polar: Power Law Residuals as yield stability index \loadmathjax In metan: Multi Environment Trials Analysis

 ge_polar R Documentation

## Power Law Residuals as yield stability index \loadmathjax

### Description

Performs a stability analysis based on the Power Law Residuals (POLAR) statistics (Doring et al., 2015). POLAR is the residuals from the linear regression of \mjseqnlog(\sigma^2) against \mjseqnlog(\mu) and can be used as a measure of crop stability with lower stability (relative to all samples with that mean yield) indicated by more positive POLAR values, and higher stability (relative to all samples with that mean yield) indicated by more negative POLAR values.

### Usage

ge_polar(.data, env, gen, resp, base = 10, verbose = TRUE)


### Arguments

 .data The dataset containing the columns related to Environments, Genotypes 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. resp The response variable(s). To analyze multiple variables in a single procedure use, for example, resp = c(var1, var2, var3). base The base with respect to which logarithms are computed. Defaults to 10. verbose Logical argument. If verbose = FALSE the code will run silently.

### Value

An object of class ge_acv, 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.

• POLAR The Power Law Residuals

• POLAR_R The rank for the ACV value.

### Author(s)

Tiago Olivoto tiagoolivoto@gmail.com

### References

Doring, T.F., S. Knapp, and J.E. Cohen. 2015. Taylor's power law and the stability of crop yields. F. Crop. Res. 183: 294-302. doi: 10.1016/j.fcr.2015.08.005

### Examples


library(metan)
out <- ge_polar(data_ge2, ENV, GEN, c(EH, PH, EL, CD, ED, NKE))
gmd(out)



metan documentation built on March 7, 2023, 5:34 p.m.