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 Piétrain boars with CC (PiCC) or CT (PiCT) halothane genotypes, and Piétrain x Duroc hybrid boars with various compositions (25% (PiDu25), 50% (PiDu50) or 75% (PiDu75) of Piétrain 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 <br />meat in comparison with pure stress-negative Piétrain, 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 stress-negative Piétrain as well as hybrid boars with different genetic constitution. Sperm concentration was lower in Summer and Autumn, higher in Winter and Spring. The Piétrain x Duroc hybrid boars, especially PiDu75 seem to be promising as terminal boars.