agridat (version 1.8.1)

brandle.rape: Three-way table of rape seed yields

Description

Rape seed yields

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.

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. This should be changed to 2555 to match the means reported in the paper.

Examples

dat <- brandle.rape

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

# 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)
dat$year <- factor(dat$year)
m1 <- lmer(yield ~ year + loc + year:loc + (1|gen) +
           (1|gen:loc) + (1|gen:year), data=dat)
print(VarCorr(m1), comp=c('Variance','Std.Dev.'))
## Groups   Name        Variance Std.Dev.
## gen:loc  (Intercept)  9362.9   96.762 
## gen:year (Intercept) 14030.0  118.448 
## gen      (Intercept) 72628.5  269.497 
## Residual             75008.1  273.876