data("burgueno.unreplicated")

## Not run: 

  library(agridat)
  data(burgueno.unreplicated)
  dat <- burgueno.unreplicated

  # Define a 'check' variable for colors
  dat$check <- ifelse(dat$gen=="G000", 2, 1)
  # Every fourth column is the 'check' genotype
  libs(desplot)
  desplot(dat, yield ~ col*row,
          col=check, num=gen, #text=gen, cex=.3, # aspect unknown
          main="burgueno.unreplicated")

  libs(asreml,lucid) # asreml4

  # AR1 x AR1 with random genotypes
  dat <- transform(dat, xf=factor(col), yf=factor(row))
  dat <- dat[order(dat$xf,dat$yf),]
  m2 <- asreml(yield ~ 1, data=dat, random = ~ gen,
               resid = ~ ar1(xf):ar1(yf))
  vc(m2)
  ##       effect component std.error z.ratio bound 
  ##          gen    0.9122   0.127       7.2     P 0  
  ##     xf:yf(R)    0.4993   0.05601     8.9     P 0  
  ## xf:yf!xf!cor   -0.2431   0.09156    -2.7     U 0  
  ## xf:yf!yf!cor    0.1255   0.07057     1.8     U 0.1
  
  # Note the strong saw-tooth pattern in the variogram.  Seems to
  # be column effects.
  plot(varioGram(m2), xlim=c(0,15), ylim=c(0,9), zlim=c(0,0.5),
       main="burgueno.unreplicated - AR1xAR1")
  # libs(lattice) # Show how odd columns are high
  # bwplot(resid(m2) ~ col, data=dat, horizontal=FALSE)
  
  # Define an even/odd column factor as fixed effect
  # dat$oddcol <- factor(dat$col 
  # The modulus operator throws a bug, so do it the hard way.
  dat$oddcol <- factor(dat$col - floor(dat$col / 2) *2 )
  
  m3 <- update(m2, yield ~ 1 + oddcol)
  m3$loglik # Matches Burgueno table 3, line 3
  
  plot(varioGram(m3), xlim=c(0,15), ylim=c(0,9), zlim=c(0,0.5),
       main="burgueno.unreplicated - AR1xAR1 + Even/Odd")
  # Much better-looking variogram
  

## End(Not run)