Multi-environment trial of corn, balanced incomplete block design

Balanced incomplete block design in corn

Format

A data frame with 52 observations on the following 3 variables.

loc

location/block, 13 levels

gen

genotype/line, 13 levels

yield

yield, pounds/plot

Details

Incomplete block design. Each loc/block has 4 genotypes/lines. The blocks are planted at different locations.

Conducted in 1943 in North Carolina.

Source

North Carolina Agricultural Experiment Station, United States Department of Agriculture.

References

Cochran, W.G. and Cox, G.M. (1957), Experimental Designs, 2nd ed., Wiley and Sons, New York, p. 448.

Examples

if (FALSE) { # \dontrun{

library(agridat)

data(cochran.bib)
dat <- cochran.bib

# Show the incomplete-block structure
libs(lattice)
redblue <- colorRampPalette(c("firebrick", "lightgray", "#375997"))
levelplot(yield~loc*gen, dat,
          col.regions=redblue,
          xlab="loc (block)", main="cochran.bib - incomplete blocks")

with(dat, table(gen,loc))
rowSums(as.matrix(with(dat, table(gen,loc))))
colSums(as.matrix(with(dat, table(gen,loc))))

m1 = aov(yield ~ gen + Error(loc), data=dat)
summary(m1)

libs(nlme)
m2 = lme(yield ~ -1 + gen, data=dat, random=~1|loc)

} # }