Performs a stability analysis based on the geometric mean (GAI), according to the following model (Mohammadi and Amri, 2008): \[GAI = \sqrt[E]{{\mathop {\bar Y}\nolimits_1 + \mathop {\bar Y}\nolimits_2 + ... + \mathop {\bar Y}\nolimits_i }}\] where \(\bar Y_1\), \(\bar Y_2\), and \(\bar Y_i\) are the mean yields of the first, second and i-th genotypes across environments, and E is the number of environments
gai(.data, env, gen, rep, resp, verbose = TRUE)
.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, |
verbose | Logical argument. If |
An object of class gai
, 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.
GAI Geometric adaptability index
GAI_R The rank for the GAI value.
Mohammadi, R., & Amri, A. (2008). Comparison of parametric and non-parametric methods for selecting stable and adapted durum wheat genotypes in variable environments. Euphytica, 159(3), 419-432. doi: 10.1007/s10681-007-9600-6 .
Tiago Olivoto tiagoolivoto@gmail.com