huehn.wheat {agridat} | R Documentation

## Multi-environment trial of wheat to illustrate stability statistics

### Description

Multi-environment trial to illustrate stability statistics

### Usage

    data("huehn.wheat")

### 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.

### Source

Manfred Huehn (1979). Beitrage zur Erfassung der phanotypischen Stabilitat I. Vorschlag einiger auf Ranginformationen beruhenden Stabilitatsparameter. EDV in Medizin und Biologie, 10 (4), 112-117. Table 1. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-145979

### 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

    ## 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
    }

    ## End(Not run)

[Package agridat version 1.16 Index]