agridat (version 1.16)

piepho.cocksfoot: Heading dates for cock's foot on 25 varieties in 7 years

Description

Heading dates for cock's foot on 25 varieties in 7 years

Usage

data("piepho.cocksfoot")

Format

A data frame with 111 observations on the following 3 variables.

gen

genotype factor, 25 levels

year

year, numeric

date

heading date (days from April 1)

Details

These data are heading dates (days from April 1 to heading) of 25 cock's foot Dactylis glomerata varieties in trials at Hannover, Germany, repeated over seven years. Values are means over replications.

Examples

# NOT RUN {
data(piepho.cocksfoot)
dat <- piepho.cocksfoot
dat$env <- factor(dat$year)

require(lattice)
densityplot(~date|env, data=dat, main="piepho.cocksfoot - heading date") # Gaussian, not gamma distn

# }
# NOT RUN {
  require(lme4)
  # A simple mixed model gives results similar to Piepho, Table 2.
  m1 <- lmer(date ~ -1 + gen + (1|env), data=dat)
  summary(m1)
  ## Fixed effects:
  ##        Estimate Std. Error t value
  ## genG01   48.951      1.744   28.07
  ## genG02   42.270      1.755   24.09
  ## genG03   45.293      1.744   25.98
  ## genG04   45.467      1.744   26.08
  ## genG05   44.215      1.755   25.20
# }
# NOT RUN {
# }