stability.er {agrostab}

Regression on Environmental Index

Description

This function calculates the Erberhart&Rassel's stability parameters and the Dragavtsev's coefficient of multiplicativity.

Usage

stability.er(dataf, res_var, gen_var, env_var, rep_var, plotIt = TRUE)

Arguments

dataf

the name of the data frame containing the data to analyze.

res_var

the response variable.

gen_var

the genotypes variable.

env_var

the environments variable.

rep_var

the replications variable.

plotIt

a logical value specifying if plot should be drawn; default is TRUE

Value

Returns a list of three objects:

ANOVA

the analysis of variance table

scores

the data frame object of stability analysis results:

• bi regression of genotype means on environmental index

• t_value t-values for gypothesis that bi=1

• p_value p-values for gypothesis that bi=1

• s2di individual squared deviation from regression

• pf_value p-values for gypothesis that s2di=0

• ai Dragavtsev's coefficient of multiplicativity

Ij

enviromental indexes

References

Eberhart, S.A. and W.A. Russell. 1966. Stability parameters for comparing varieties. Crop Sci 6: 36-40. doi:10.2135/cropsci1966.0011183X000600010011x

Examples

data(exp_data)
stability.er(exp_data,"yield","gen","env","rep")