agridat (version 1.8.1)

kempton.slatehall: Slate Hall Farm 1976 spring wheat

Description

Yields for a trial at Slate Hall Farm in 1976.

source

R A Kempton and P N Fox. (1997). Statistical Methods for Plant Variety Evaluation, Chapman and Hall. Page 84.

Details

The trial was a balanced lattice with 25 varieties in 6 replicates, 10 ranges of 15 columns. The plot size was 1.5 meters by 4 meters. Each row within a rep is an (incomplete) block.

References

Gilmour, Arthur R and Robin Thompson and Brian R Cullis. (1994). Average Information REML: An Efficient Algorithm for Variance Parameter Estimation in Linear Mixed Models, Biometrics, 51, 1440-1450.

Examples

dat <- kempton.slatehall
desplot(yield ~ col * row, dat, num=gen, out1=rep,
        main="kempton.slatehall")

dat <- transform(dat, xf=factor(col), yf=factor(row))

# Incomplete block model of Gilmour et al 1995
require(lme4)
m1 <- lmer(yield ~ gen + (1|rep) + (1|rep:yf) + (1|rep:xf), data=dat)
print(VarCorr(m1), comp=c("Variance","Std.Dev."))
## Groups   Name        Variance Std.Dev.
## rep:xf   (Intercept) 14811.6  121.703
## rep:yf   (Intercept) 15595.0  124.880
## rep      (Intercept)  4262.4   65.287
## Residual              8061.8   89.788

# Incomplete block model of Gilmour et al 1995
require("asreml")
m2 <- asreml(yield ~ gen, random = ~ rep/(xf+yf), data=dat)
summary(m2)$varcomp
# Table 4
predict(m2, classify="gen")$predictions$pvals