agridat (version 1.5)

denis.missing: Multi-environment trial with structured missing values

Description

Grain yield was measured on 5 genotypes in 26 environments. Missing values were non-random, but structured.

Usage

data(denis.missing)

source

Denis, J. B. and C P Baril, 1992, Sophisticated models with numerous missing values: The multiplicative interaction model as an example. Biul. Oceny Odmian, 24--25, 7--31. Used with permission of Jean-Baptists Denis.

References

H P Piepho, (1999) Stability analysis using the SAS system, Agron Journal, 91, 154--160.

Examples

dat <- denis.missing

# View missingness structure
require("reshape2")
m1 <- melt(dat, measure.var='yield')
acast(m1, env~gen)

# Stability variance (Table 3 in Piepho)
library("nlme")
dat.lme <- lme(yield ~ -1 + gen, data=dat, random= ~ 1|env,
               weights = varIdent(form= ~ 1|gen),
               na.action=na.omit)
dat.lme$sigma^2 * c(1, coef(dat.lme$modelStruct$varStruct, unc = FALSE))^2