(1992, 1993) that "models assuming strictly

additive genetic effects, even if appropriate at the within-population level, may tell us little about the actual genetic divergence of populations." We might add that assuming other nonlinear effects such as genotype-by-environment interaction can be ignored may also be misleading.

Additive genetic effects <a, [??], heat tolerance (fv, [??]), and

additive genetic effects plus heat tolerance (a+fv,[??]).

Most of crosses with good SCA effects may be either due to good GCA of parents, indicating the preponderance of

additive genetic effects (Kenga et al., 2004).

Genotypic variance observed in the [F.sub.2] generation in this study might be attributed primarily to

additive genetic effects, since the variance estimates of this effect were substantially greater than the variance estimates of dominance (Table 2).

Multiple Trait Gibbs Sampler for Animal Models (MTGSAM) was employed (Van Tassell & Van Vleck, 1995), which executes Bayesian estimates; normal a priori distribution may be taken into account for

additive genetic effects, common environment of larva culture, nursery and residual.

The average of nearly 100 estimates indicate that, assuming no epistasis and no linkage,

additive genetic effects on average account for 61.2% and dominance accounted for 38.8% of total genetic effects (cf., Hallauer and Miranda, Fo., 1988).

Following the model developed by Kirkpatrick and Lande (1989) for maternal inheritance, the offspring trait can be decomposed into three parts: (1)

additive genetic effects ([a.sub.o]); (2) random environmental effects ([e.sub.o]); and (3) maternal environmental effects, such that

The association between genotypes and marbling was significant (P<0.0001), showing that genotypes AA (5.866 +- 0.15) had a more significant effect on MAR followed by GG (5.325 +- 0.08) and AG (5.034 +- 0.09), with significant

additive genetic effects (P<0.001).

Where, Y is a vector corresponds to the phenotypic values for weight gain traits and growth curve parameter traits; b is the vector of fixed effects including batch, lines, sex, and; a is a vector of random

additive genetic effects, assumed to be a ~ N (0, A [[sigma].sup.2.sub.a])

In the threshold model, it was assumed that the underlying (Liability) scalehas a normal continuous distribution, being represented as: |[theta] ~ N(W[theta], I[[sigma].sub.e.sup.2]), where is U the base scale vector of order r; [theta]=(b.a) is the location parameter vector of order s with b (defined as fixed effects from the frequency point of view), and order s with a (as random direct

additive genetic effects); W is the known incidence matrix of order r x s; I is the identity matrix of order r x r and [[sigma].sub.e.sup.2] is the residual variance.

[gamma] = vector of the observations for the trait (W205); X = matrix of incidence of the fixed effects (CG, sex, BS, WS e CA); [Z.sub.1] = matrix of incidence associated with direct

additive genetic effects; [Z.sub.2] = matrix of incidence associated with maternal

additive genetic effects; [beta], a and [epsilon] = vector of solutions for the fixed effects, vector of direct

additive genetic effects and vector of maternal

additive genetic effects, respectively and e = vector of residues.

The percent phenotypic variation explained by the significant intervals and estimates of their

additive genetic effects were also calculated in MapQTL.