agridat (version 1.23)

theobald.barley: Multi-environment trial of barley, multiple years & fertilizer levels

Description

Barley yields at multiple locs, years, fertilizer levels

Usage

data("theobald.barley")

Format

A data frame with 105 observations on the following 5 variables.

yield

yield, tonnes/ha

gen

genotype

loc

location, 5 levels

nitro

nitrogen kg/ha

year

year, 2 levels

Details

Theobald and Talbot used BUGS to fit a fully Bayesian model for yield response curves.

Locations of the experiment were in north-east Scotland.

Assumed nitrogen cost 400 pounds per tonne. Grain prices used were 100, 110, and 107.50 pounds per tonne for Georgie, Midas and Sundance.

Examples

if (FALSE) {

library(agridat)

data(theobald.barley)
dat <- theobald.barley
dat <- transform(dat,  env=paste(loc,year,sep="-"))
dat <- transform(dat, income=100*yield - 400*nitro/1000)

libs(lattice)
xyplot(income~nitro|env, dat, groups=gen, type='b',
       auto.key=list(columns=3), main="theobald.barley")

}