This study was conducted to evaluate the effects of genetic background and season on growth performance and semen quality of boars. Five genetic groups were evaluated, including stress-negative Pietrain boars with CC (PiCC) or CT (PiCT) halothane genotypes, and Pietrain x Duroc hybrid boars with various compositions (25 percent PiDu25, 50 percent (PiDu50) or 75 percent (PiDu75) of Pietrain origin) The results showed that genetic group has a significant effect on growth performance and semen quality. The hybrid boars PiDu25, PiDu50 and PiDu75 had better growth rate, but lower lean meat in comparison with pure stress-negative Pietrain, except PiDu75 boars. PiDu25, PiDu50 and PiCC boars demonstrated high semen quality. A season effect was observed on most of semen quality traits of pure stressnegative Pietrain as well as hybrid boars with different genetic constitution. Sperm concentration was lower in Summer and Autumn, higher in Winter and spring. The Pietrain x Duroc hybrid boars, especially PiDu75 seem to be promising as terminal boars.