ai] is additive genetic variance
for trait i; [[sigma].
Additive genetic variances
were found for number of grains per row and number of grain rows per ear under high density plantation (Borghi et al.
For PY, the additive genetic variances
showed the same trend as the phenotypic variances, with the observation of higher values at the end of lactation.
Concerning lato sensu, the heritability can be defined as the ratio between the genotypic variance and phenotypic variance, while, the stricto sensu one is defined as the ratio between additive genetic variance
and phenotypic variance.
According to Paterniani (1967), it is of interest that the additive genetic variance
is maintained as high as possible to allow the achievement of substantial gains by selection.
It is known that small populations give imprecise estimates of additive genetic variance
and heritability, and the high standard errors on variances and heritabilities in this study illustrate this point.
A, additive genetic variance
component; E, unique environmental variation.
1998) show that moving from a univariate to a quadrivariate analysis more than doubles the power to detect additive genetic variance
so we may assume that our power to detect it in this study is at least 80 percent.
First, as derived by Knapp and Bridges (1990), an additional clonal replicate of a progeny can increase statistical power, which is analogous to adding another progeny genotype if all the additive genetic variance
is explained by markers (this condition may be partially met because the significant markers I identified accounted for large percentages of the genetic variance; see Results).
A model comprising additive genetic variance
(DR) and within family environmental variance (E1) was a good fit to the data, explaining 89.
We were then also able to determine the intensity of selection, the heritability, and the additive genetic variance
of development time separately for each sex.
The additive genetic variance
across age at calving increased steadily till around 80 months and then drops till 130 months of calving and then tends to show a plateau till the end of age at calving.
Direct additive genetic variance
in both models presented equivalent variance component progression along the days of weighting (Figure 1).
The heritability is a ratio between additive genetic variance
and total phenotypic variance.
Heritability was estimated as the ratio of the additive genetic variance
to total phenotypic variance; and repeatability, as the ratio of the sum of the additive genetic variance
plus permanent environmental variance to phenotypic variance, as described by Falconer and Mackay (2001), according Equation 4 and 5: