The objective of this study was to estimate genetic parameters on days to 90 kg body weight andultrasound measured traits (back fat thickness, eye muscle area, retail cut percentage) and predict geneticprogress when the weights for selection on the paternal traits of Duroc, which can be incorporated into sireline selection indexes. A simulation program, ZPLAN+, was used for the simulation. Genetic parameters ofdays to 90 kg body weight (D90KG), back fat thickness (BFT), eye muscle area (EMA) and retail cutpercentage (RCP) used in the simulation were estimated from 27,972 heads of farm tested Duroc pigs from2005 to July, 2012. Parameters of simulation used genetic parameters with parturition rates, ratios of test pigsand replacement rates that were dependent on selection protocols of simulated farms. Different weights ofselection for traits of days to 90 kg and backfat thickness were compared. Estimates of heritability were 0.406,0.355, 0.159 and 0.379 for D90KG, BFT, EMA and RCP, respectively. Genetic correlation of D90KG with BFT,EMA and RCP were –0.043, 0.049 and 0.021, respectively. Genetic correlation of BFT with EMA and RCPwere –0.394 and –0.937. And genetic correlation between EMA with RCP were 0.524. Simulation resultshowed that index weight of 3:1 on D90KG and BFT was effective to shorten days to 90 kg without anysignificant changes in backfat thickness. Generally the genetic changes were greater as parturition rate andratios of test pigs increased. Increase in replacement rate had a small effect on genetic changes in negativeway. Thus, we recommend that index weight of 3:1 on days to 90 kg and backfat thickness could be utilizedfor sire line selection.