crossa.wheat {agridat} | R Documentation

## Multi-environment trial of wheat for 18 genotypes at 25 locations

### Description

Wheat yields for 18 genotypes at 25 locations

### Format

A data frame with 450 observations on the following 3 variables.

`loc`

  location

`locgroup`

  location group: Grp1-Grp2

`gen`

  genotype

`gengroup`

  genotype group: W1, W2, W3

`yield`

  grain yield, tons/ha

### Details

Grain yield from the 8th Elite Selection Wheat Yield Trial to evaluate 18 bread wheat genotypes at 25 locations in 15 countries.

Cross et al. used this data to cluster loctions into 2 mega-environments and clustered genotypes into 3 wheat clusters.

Locations

Code | Country | Location | Latitude (N) | Elevation (m)
AK | Algeria | El Khroub | 36 | 640
AL | Algeria | Setif | 36 | 1,023
BJ | Bangladesh | Joydebpur | 24 | 8
CA | Cyprus | Athalassa | 35 | 142
EG | Egypt | E1 Gemmeiza | 31 | 8
ES | Egypt | Sakha | 31 | 6
EB | Egypt | Beni-Suef | 29 | 28
IL | India | Ludhiana | 31 | 247
ID | India | Delhi | 29 | 228
JM | Jordan | Madaba | 36 | 785
KN | Kenya | Njoro | 0 | 2,165
MG | Mexico | Guanajuato | 21 | 1,765
MS | Mexico | Sonora | 27 | 38
MM | Mexico | Michoacfin | 20 | 1,517
NB | Nepal | Bhairahwa | 27 | 105
PI | Pakistan | Islamabad | 34 | 683
PA | Pakistan | Ayub | 32 | 213
SR | Saudi Arabia | Riyadh | 24 | 600
SG | Sudan | Gezira | 14 | 411
SE | Spain | Encinar | 38 | 20
SJ | Spain | Jerez | 37 | 180
SC | Spain | Cordoba | 38 | 110
SS | Spain | Sevilla | 38 | 20
TB | Tunisia | Beja | 37 | 150
TC | Thailand | Chiang Mai | 18 820

### Source

Crossa, J and Fox, PN and Pfeiffer, WH and Rajaram, S and Gauch Jr, HG. (1991). AMMI adjustment for statistical analysis of an international wheat yield trial. Theoretical and Applied Genetics, 81, 27–37. http://doi.org/10.1007/BF00226108

Used with permission of Jose' Crossa.

### References

Jean-Louis Laffont, Kevin Wright and Mohamed Hanafi (2013). Genotype + Genotype x Block of Environments (GGB) Biplots. Crop Science, 53, 2332-2341. http://doi.org/10.2135/cropsci2013.03.0178

### Examples

    ## Not run:

    library(agridat)
    data(crossa.wheat)
    dat <- crossa.wheat

    # AMMI biplot.  Fig 3 of Crossa et al.
    require(agricolae)
    m1 <- with(dat, AMMI(E=loc, G=gen, R=1, Y=yield))
    b1 <- m1$biplot[,1:4]
    b1$PC1 <- -1 * b1$PC1 # Flip vertical
    plot(b1$yield, b1$PC1, cex=0.0,
         text(b1$yield, b1$PC1, cex=.5, labels=row.names(b1),col="brown"),
         main="crossa.wheat AMMI biplot",
         xlab="Average yield", ylab="PC1", frame=TRUE)
    mn <- mean(b1$yield)
    abline(h=0, v=mn, col='wheat')

    g1 <- subset(b1,type=="GEN")
    text(g1$yield, g1$PC1, rownames(g1), col="darkgreen", cex=.5)

    e1 <- subset(b1,type=="ENV")
    arrows(mn, 0,
           0.95*(e1$yield - mn) + mn, 0.95*e1$PC1,
           col= "brown", lwd=1.8,length=0.1)

    # GGB example
    library(agridat)
    data(crossa.wheat)
    dat2 <- crossa.wheat
    library(gge)
    # Specify env.group as column in data frame
    m2 <- gge(yield~gen*loc, dat2, env.group=locgroup, scale=FALSE)
    biplot(m2, main="crossa.wheat - GGB biplot")

    ## End(Not run)

[Package agridat version 1.16 Index]