抄録
Antagonistic genetic correlations between growth and reproductive traits exist in broilers, making it difficult to improve these traits simultaneously. In the present study, two selection schemes for achieving desired genetic gains in antagonistically correlated traits were compared in simulation. The population structure and genetic parameters were determined on the basis of an existing broiler line. The first selection scheme (DIS scheme) was based on selection index for achieving desired genetic gains. In the second (FI+LP scheme), a combination of the family index and linear programming technique was applied. The simulated traits were body weight at 6 weeks (BW) and age at sexual maturity of hen (SM). Based on the estimate from the analysis of an actual data set, a positive genetic correlation between the two traits was assumed. This is a typical case of antagonistic selection because a positive gain in BW and a negative gain in SM were required for achieving the breeding goal. The results obtained are summarized as follows: (1) Both DIS and HI+LP schemes produced similar genetic gain averaged over replicates; (2) FI+LP scheme reduced the variance of genetic gain among replicates to 5-70% of DIS scheme; and (3) FI+LP scheme showed a strong robustness against error in the estimate of genetic correlation. In light of these results, it was concluded that FI+LP scheme should be preferable to DIS scheme in developing closed lines of broilers.
