agridat (version 1.12)

yan.winterwheat: Multi-environment trial of Winter Wheat in Ontario

Description

Yield of 18 varieties of winter wheat grown at 9 environments in Ontario in 1993.

Format

A data frame with 162 observations on the following 3 variables.

gen

Genotype factor

env

Environment factor

yield

Yield in metric tons per hectare

Details

The yield is the mean of several reps, measured in metric tons per hectare.

This data has often been used to illustrate GGE biplots.

References

Weikai Yan and Manjit S. Kang and Baoluo Ma and Sheila Woods, 2007, GGE Biplot vs. AMMI Analysis of Genotype-by-Environment Data, Crop Science, 2007, 47, 641--653.

Examples

# NOT RUN {
data(yan.winterwheat)
dat <- yan.winterwheat

require("reshape2")
mat <- melt(dat, id.var=c('gen','env'))
mat <- acast(mat, gen~env)

mat.sc <- scale(mat)

# Environment-standardized GGE biplot
# biplot(princomp(mat.sc), main="yan.winterwheat - GGE biplot")

m1 <- gge(yield ~ gen*env, data=dat)
biplot(m1, flip=c(0,1), title="yan.winterwheat - GGE biplot")

# }