The study was conducted with the use of data regarding the evaluation of potato tuber deformations, collected during varietal experiments at the Potato Agronomy Department, Plant Breeding and Acclimatization Institute - National Research Institute, Division in Jadwisin, Poland. The purpose of the study was the estimation of tuber deformations in the genotype x environment interaction. The analysis was performed using the SERGEN 4 software. The study included 21 potato cultivars, cultivated for a period of five years on a light soil. Particular years of the investigations were taken as different environments (weather conditions → rainfall + air temperature). Among the cultivars tested in variable environmental conditions, stable and unstable cultivars were identified. Moreover, an estimation of the influence of the particular years on the cultivation of the chosen potato cultivars was performed. It was found, the environment profoundly modifies the share of tuber deformation in the yield.