brandle.rape {agridat} | R Documentation

## Multi-environment trial of rape

### Description

Rape seed yields for 5 genotypes, 3 years, 9 locations.

### Format

A data frame with 135 observations on the following 4 variables.

`gen`

  genotype

`year`

  year, numeric

`loc`

  location, 9 levels

`yield`

  yield, kg/ha

### Details

The yields are the mean of 4 reps.

Note, in table 2 of Brandle, the value of Triton in 1985 at Bagot is shown as 2355, but should be 2555 to match the means reported in the paper.

### Source

Brandle, JE and McVetty, PBE. (1988). Genotype x environment interaction and stability analysis of seed yield of oilseed rape grown in Manitoba. Canadian Journal of Plant Science, 68, 381–388.

Used with permission of P. McVetty.

### Examples

    data(brandle.rape)
    dat <- brandle.rape

    require(lattice)
    dotplot(gen~yield|loc, dat, group=year, auto.key=list(columns=3),
            main="brandle.rape, yields per location", ylab="Genotype")

    # Matches table 4 of Brandle
    round(tapply(dat$yield, dat$gen, mean),0)

    ## Not run:
      # Brandle reports variance components:
      # sigma^2_gl: 9369  gy: 14027 g: 72632 resid: 150000
      # Brandle analyzed rep-level data, so the residual variance is different.
      # The other components are matched by the following analysis.

      require(lme4)
      require(lucid)
      dat$year <- factor(dat$year)
      m1 <- lmer(yield ~ year + loc + year:loc + (1|gen) +
                   (1|gen:loc) + (1|gen:year), data=dat)
      vc(m1)
      ##      grp        var1 var2  vcov  sdcor
      ##  gen:loc (Intercept) <NA>  9363  96.76
      ## gen:year (Intercept) <NA> 14030 118.4
      ##      gen (Intercept) <NA> 72630 269.5
      ## Residual        <NA> <NA> 75010 273.9

    ## End(Not run)

[Package agridat version 1.16 Index]