kang.maize {agridat} | R Documentation

## Multi-environment trial of maize in Louisianna at 4 locs in 3 years

### Description

Maize yields at 4 locs in 3 years in Louisianna.

### Usage

    data("kang.maize")

### Format

`gen`

  genotype, 17 levels

`env`

  environment, 12 levels

`yield`

  yield, tonnes/ha

  environment, 13 levels

`year`

  year, 85-87

`loc`

  location, 4 levels

### Details

Yield trials were conducted at four locations (Alexandria, Baton Rouge, Bossier City, and St. Joseph) in Louisiana during 1985 to 1987. Each loc was planted as RCB design with 4 reps. Mean yields are given in this data.

### Source

Kang, MS and Gorman, DP. (1989). Genotype x environment interaction in maize. Agronomy Journal, 81, 662-664. Table 2.

Used with permission of Dan Gorman.

### Examples

    data(kang.maize)
    dat <- kang.maize

    # Sweep out loc means, then show interaction plot.
    if(require(reshape2)){
    mat <- acast(dat, gen~env, value.var='yield')
    mat <- sweep(mat, 2, colMeans(mat))
    dat2 <- melt(mat)
    names(dat2) <- c('gen','env','yield')
    require(lattice)
    xyplot(yield~env|gen, data=dat2, type='l', group=gen,
           panel=function(x,y,...){
             panel.abline(h=0,col="gray70")
             panel.xyplot(x,y,...)
           },
           ylab="Environment-centered yield",
           main="kang.maize - maize hybrid yields", scales=list(x=list(rot=90)))
    }

    # Weather covariates for each environment.
    covs <- data.frame(env=c("AL85","AL86","AL87", "BR85","BR86","BR87",
                         "BC85","BC86","BC87", "SJ85","SJ86","SJ87"),
                       maxt=c(30.7,30.2,29.7,31.5,29.4,28.5, 31.9, 30.4,31.7, 32,29.6,28.9),
                       mint=c(18.7,19.3,18.5, 19.7,18,17.2, 19.1,20.4,20.3, 20.4,19.1,17.5),
                       rain=c(.2,.34,.22, .28,.36,.61, .2,.43,.2, .36,.41,.22),
                       humid=c(82.8,91.1,85.4, 88.1,90.9,88.6, 95.4,90.4,86.7, 95.6,89.5,85))

[Package agridat version 1.16 Index]