omer.sorghum {agridat} | R Documentation

## Yield of sorghum in 3 years, 2 locations

### Description

Yield of sorghum in 3 years, 2 locations

### Usage

    data("omer.sorghum")

### Format

A data frame with 432 observations on the following 4 variables.

`env`

  environment

`rep`

  replication

`gen`

  genotype factor

`yield`

  yield, kg/ha

### Details

Trials were conducted in Sudan, 3 years at 2 locations, 4 reps in RCBD at each location.

### Source

Siraj Osman Omer, Abdel Wahab Hassan Abdalla, Mohammed Hamza Mohammed, Murari Singh (2015). Bayesian estimation of genotype-by-environment interaction in sorghum variety trials Communications in Biometry and Crop Science, 10 (2), 82-95.

Electronic data provided by Siraj Osman Omer.

### References

None.

### Examples

    ## Not run:

    data(omer.sorghum)
    dat <- omer.sorghum

    # REML approach
    require(lme4)
    require(lucid)

    # 1 loc, 2 years. Match Omer table 1.
    m1 <- lmer(yield ~ 1 + env + (1|env:rep) + (1|gen) + (1|gen:env),
               data=subset(dat, is.element(env, c('E2','E4'))))
    vc(m1)
    ##      grp        var1 var2    vcov  sdcor
    ##  gen:env (Intercept) <NA> 17050   130.6
    ##      gen (Intercept) <NA>  2760    52.54
    ##  env:rep (Intercept) <NA>   959.1  30.97
    ## Residual        <NA> <NA> 43090   207.6

    # 1 loc, 3 years. Match Omer table 1.
    m2 <- lmer(yield ~ 1 + env + (1|env:rep) + (1|gen) + (1|gen:env),
               data=subset(dat, is.element(env, c('E2','E4','E6'))))
    vc(m2)
    ##      grp        var1 var2  vcov  sdcor
    ##  gen:env (Intercept) <NA> 22210 149
    ##      gen (Intercept) <NA>  9288  96.37
    ##  env:rep (Intercept) <NA>  1332  36.5
    ## Residual        <NA> <NA> 40270 200.7

    # all 6 locs. Match Omer table 3, frequentist approach
    m3 <- lmer(yield ~ 1 + env + (1|env:rep) + (1|gen) + (1|gen:env),
               data=dat)
    vc(m3)
    ##       grp        var1 var2  vcov  sdcor
    ##   gen:env (Intercept) <NA> 21340 146.1
    ##   env:rep (Intercept) <NA>  1152  33.95
    ##       gen (Intercept) <NA>  1169  34.2
    ##  Residual        <NA> <NA> 24660 157

    ## End(Not run)

[Package agridat version 1.16 Index]