Estimation of Genetic Variance of Quantitative Trait Based on Polymorphic Gene Locus

Based on polymorphic gene locus, a plan to analyze the genetic variation of quantitative trait has been found in this paper. At polymorphic gene locus, the variance components of quantitative trait was described as follows:V A=2βp and V G=p′Xp G 2 in which p=column vector of polymorphic allele frequencies,β=row vector of (gene average effect) 2,X=[a 2 ij ] i×i matrix,a ij =genotype value,and G=population mean (deviation).The genotypic value from the observed value of quantitative trait was estimated by least square model with the restriction Σ(a ii )=0.The variance components of some quantitative traits were estimated based on serum enzyme Tf,Amy, 6 PGD,PHI,and Postalbumin 2 (PO 2) loci.The results showed that the effects of Tf and Am locus to reproductive traits and carcass quality characters were faintness. The 6 PGD loci was very important in the effect on the variation of meat pH (dominated by V A) and daily gain (dominated by V D).The PO 2 locus was also important in the effect on tenderness, water holding capacity,pH and daily gain.The leading variation was V D in PO 2 to meat tenderness, compared with V A to daily gain and water holding capacity. The effect of PHI locus to carcass character variation, but to tenderness, was faintness.