brandle.rape: Multi-environment trial of rape

Description

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

Arguments

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.

Examples

Run this code

# NOT RUN {
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
  
# }
# NOT RUN {


# }

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