To screen the whole porcine chromosome 12 for QTL affecting economically important traits, ten genetic markers were genotyped in two F2 populations generated from the cross of genetically diverse breeds: European Wild pig and commercial pig breed Pietrain (W x P), and Chinese Meishan and Pietrain (M x P). Fifty-one traits were recorded. A least squares method was used for chromosome-wide screening for QTL. An association analysis between genotypes at the GH locus and traits was also carried out. The least squares analysis did not reveal the presence of genome-wide significant QTL affecting the traits, while the association study showed significant (P < 0.01) associations between GH genotypes and fatness traits in M x P, but not in W x P. F2 pigs carrying the genotype C1A2/C4A2 at the GH locus displayed the thinnest backfat (21.76 mm), while the ones carrying the genotype C2A2/C2A2 had the thickest (31.41 mm).