jansen.apple {agridat}R Documentation

Infestation of apple shoots by apple canker.

Description

Infestation of apple shoots by apple canker.

Usage

data("jansen.apple")

Format

A data frame with 36 observations on the following 5 variables.

inoculum

inoculum level

gen

genotype/variety

block

block

y

number of inoculations developing canker

n

number of inoculations

Details

Shoots of apple trees were infected with fungus Nectria galligena, which may cause apple canker.

The incoulum density treatment had 3 levels, measured in macroconidia per ml.

There were 4 blocks.

Source

J. Jansen & J.A. Hoekstra (1993). The analysis of proportions in agricultural experiments by a generalized linear mixed model. Statistica Neerlandica, 47(3), 161-174. http://doi.org/10.1111/j.1467-9574.1993.tb01414.x

Used with permission of J. Jansen. Electronic version supplied by Miroslav Zoric.

References

None.

Examples

data(jansen.apple)
dat <- jansen.apple

require(lattice)
xyplot(inoculum ~ y/n|gen, data=dat, group=block,
       layout=c(3,1),
       main="jansen.apple",
       xlab="Proportion infected per block/inoculum",
       ylab="Inoculum level")

## Not run: 
  require(lme4)
  # Tentative model.  Needs improvement.
  m1 <- glmer(cbind(y,n-y) ~ gen + factor(inoculum) + (1|block),
              data=dat, family=binomial)
  summary(m1)

## End(Not run)


[Package agridat version 1.16 Index]