theobald.barley {agridat} | R Documentation

## 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.

### Source

Chris M. Theobald and Mike Talbot, (2002). The Bayesian choice of crop variety and fertilizer dose. Appl Statistics, 51, 23-36. http://doi.org/10.1111/1467-9876.04863

Data provided by Chris Theobald and Mike Talbot.

### Examples

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

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

[Package agridat version 1.16 Index]