becker.chicken {agridat} R Documentation

## Mating crosses of chickens

### Description

Mating crosses of chickens

### Usage

`data("becker.chicken")`

### Format

A data frame with 45 observations on the following 3 variables.

`male`

male parent

`female`

female parent

`weight`

weight (g) at 8 weeks

### Details

From a large flock White Rock chickens, five male sires were chosen and mated to each of three female dams, producing 3 female progeny. The data are body weights at eight weeks of age.

Becker (1984) used these data to demonstrate the calculation of heritability.

### Source

Walter A. Becker (1984). Manual of Quantitative Genetics, 4th ed. Page 83.

None

### Examples

```## Not run:

library(agridat)
data(becker.chicken)
dat <- becker.chicken

libs(lattice)
dotplot(weight ~ female, data=dat, group=male,
main="becker.chicken - progeny weight by M*F",
xlab="female parent",ylab="progeny weight",
auto.key=list(columns=5))

# Sums match Becker
# sum(dat\$weight)
# aggregate(weight ~  male + female, dat, FUN=sum)

# Variance components
libs(lme4,lucid)
m1 <- lmer(weight ~  (1|male) + (1|female), data=dat)
# vc(m1)
## grp        var1 var2      vcov    sdcor
## 1   female (Intercept) <NA> 1096   33.1
## 2     male (Intercept) <NA>  776.8 27.87
## 3 Residual        <NA> <NA> 5524   74.32

# Calculate heritabilities
# s2m <- 776  # variability for males
# s2f <- 1095 # variability for females
# s2w <- 5524 # variability within crosses
# vp <- s2m + s2f + s2w # 7395
# 4*s2m/vp # .42 male heritability
#4*s2f/vp # .59 female heritability

## End(Not run)
```

[Package agridat version 1.18 Index]