agridat (version 1.5)

adugna.sorghum: Sorghum yields at 3 locations across 5 years

Description

Sorghum yields at 3 locations across 5 years

Usage

data(adugna.sorghum)

source

Asfaw Adugna (2008), Assessment of yield stability in sorghum using univariate and multivariate statistical approaches, Hereditas, 145, 28--37. Used with permission of Asfaw Adugna.

Details

Sorghum yields at 3 locations across 5 years. The trials were carried out at three locations in dry, hot lowlands of Ethiopia: Melkassa (39 deg 21 min E, 8 deg 24 min N), Mieso (39 deg 22 min E, 8 deg 41 min N) and Kobo (39 deg 37 min E, 12 deg 09 min N). Trial 1 was 14 hybrids and one open-pollinated variety. Trial 2 was 12 experimental lines.

Examples

data(adugna.sorghum)

dat <- adugna.sorghum

# Genotype means match Adugna
tapply(dat$yield, dat$gen, mean)

# CV for each genotype.  G1..G15 match, except for G2.
# The table in Adugna scrambles the means for G16..G28
require(reshape2)
mat <- acast(dat, gen~env,  value.var="yield")
round(sqrt(apply(mat, 1, var, na.rm=TRUE)) / apply(mat, 1, mean, na.rm=TRUE) * 100,2)

# Shukla stability.  G1..G15 match Adugna.  Can't match G16..G28.
dat1 <- droplevels(subset(dat, trial=="T1"))
mat1 <- acast(dat1, gen~env,  value.var="yield")
w <- mat1; k=15; n=8  # k=p gen, n=q env
w <- sweep(w, 1, rowMeans(mat1, na.rm=TRUE))
w <- sweep(w, 2, colMeans(mat1, na.rm=TRUE))
w <- w + mean(mat1, na.rm=TRUE)
w <- rowSums(w^2, na.rm=TRUE)
sig2 <- k*w/((k-2)*(n-1)) - sum(w)/((k-1)*(k-2)*(n-1))
round(sig2/10000,1) # Genotypes in T1 are divided by 10000