The relevance of the work was determined by the need to find effective genetic combinations to increase productivity and ensure the stability of growth processes in animals of modern “commercial genotypes”. The aim of the study was to determine the role of genotype as a determining factor in the growth and development of pigs using one-factor dispersion analysis and principal component analysis. The experiment involved 120 fattening pigs, and the test animals were divided into three groups. Group I: a combination of Large White and Landrace sows with Duroc boars of Canadian selection (Genesus) Group II: a combination of Large White and Landrace sows with Pietrain boars of French selection (Axiom) and Group III: a combination of Large White and Landrace sows with boars of the terminal line “Maxter” selected by the company “France Hybrides”. The assessment was based on the live weight of pigs of different genotypes at the age of 77-203 days, absolute and average daily gains in separate age periods, as well as the age at which they reached a pre-slaughter live weight of 80, 100, 120 and 140 kg. The results of the variance analysis showed a significant influence of genotype on all studied indicators. The greatest effect of the “genotype” factor was observed for live weight at 154 days of age (43.27%), absolute and average daily gains in the period from 182 to 203 days (44.97%), as well as the age at which live weight of 100 kg was reached (44.72%). It was confirmed that pigs in group I were inferior to their peers in other groups in the early stages of life, but in the later stages of fattening, they demonstrated a significant advantage in terms of gains and growth intensity. Animals in groups II and III were characterised by similar growth rates and did not differ statistically significantly from each other. Principal component analysis allowed to identify two stages in the process of live weight formation: the first (130-155 days) and the second (180-205 days), which are determined by different growth mechanisms and are practically independent of each other. The results confirm the key role of genotype in the formation of productive traits in pigs and can be used in the development of breeding programmes and the improvement of fattening systems
breeding, breed composition, live weight, gains, principal components