agridat (version 1.16)

huehn.wheat: Multi-environment trial of wheat to illustrate stability statistics

Description

Multi-environment trial to illustrate stability statistics

Usage

data("huehn.wheat")

Arguments

Format

A data frame with 200 observations on the following 3 variables.

gen

genotype

env

environment

yield

yield dt/ha

Details

Yields for a winter-wheat trial of 20 genotypes at 10 environments.

Note: Huehn 1979 does not use genotype-centered data when calculating stability statistics.

References

Nassar, R and Huehn, M. (1987). Studies on estimation of phenotypic stability: Tests of significance for nonparametric measures of phenotypic stability. Biometrics, 43, 45-53.

Examples

Run this code
# NOT RUN {
data(huehn.wheat)
dat <- huehn.wheat

# Nassar & Huehn, p. 51 "there is no evidence for differences in stability
# among the 20 varieties".
require(gge)
m1 <- gge(yield ~ gen*env, dat)
biplot(m1, main="huehn.wheat")

require(reshape2)
datm <- acast(dat, gen~env, value.var='yield')

apply(datm,1,mean) # Gen means match Huehn 1979 table 1
apply(datm,2,mean) # Env means
apply(datm, 2, rank) # Ranks match Huehn table 1

# Huehn 1979 did not use genotype-centered data, and his definition
# of S2 is different from later papers.
if(require(stable)){
apply(huehn(datm, corrected=FALSE), 2, round,2) # S1 matches Huehn
##          MeanRank   S1
## Jubilar      6.70 3.62
## Diplomat     8.35 5.61
## Caribo      11.20 6.07
## Cbc710      13.65 6.70

# Very close match to Nassar & Huehn 1987 table 4.
apply(huehn(datm, corrected=TRUE), 2, round,2)
##          MeanRank   S1   Z1    S2   Z2
## Jubilar      10.2 4.00 5.51 11.29 4.29
## Diplomat     11.0 6.31 0.09 27.78 0.27
## Caribo       10.6 6.98 0.08 34.49 0.01
## Cbc710       10.9 8.16 1.78 47.21 1.73
}

# }

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