Probably one of the most defining problems of our time is providing food for the growing population of the earth. The aim of today's modern plant cultivation is to minimize risk factors and maximize the possibility of success. In our experiment, we examined potato parent lines (C103, C107) and their breeding lines (C11, C20) with known osmotic stress tolerance, which, based on our previous knowledge, could be valuable breeding subjects for both our current and future research. Primary tubers were made from shoot cultures produced by in vitro micropropagation under isolated conditions, then the harvested primary tubers were planted in green house at two different plant distance and fraction group (normal: T1: 25 cm, F1: 20–45 mm and narrow: T2: 15 cm, F2: -19 mm). We examined the changes in the tuber yield, as well as the influencing role of plant distance both in the amount of harvested tubers and in the distribution between fractions. In the case of the secondary tuber, we observed the emergence dynamics, the leaf height and fresh leaf weight values before harvest, the chlorophyll-a, -b and total chlorophyll content of the fresh leaves, as well as the Fv/Fm values of the chlorophyll fluorescence in the parental pair. The tuber yield measured per plant was lower in all cases for primary tubers at narrower plant distance and for secondary tubers at T2 plant distance was also reduced by about half. Significantly different results in the amount of primary tubers harvested as a result of narrower plant distances were obtained for three (C103, C107, C20) genotypes, and for two (C103, C20) genotypes when examining the secondary tubers. The fractional distribution in the number of primary tubers was positively influenced by plant distance in genotypes C103 (2nd fraction), C20 (3rd fraction), while C107 (3rd fraction) and C11 (3rd fraction) genotypes showed a slightly decrease. The emergence dynamics of the examined secondary tubers depended to a large extent on the characteristics of the genotype, however, the plant distance and fractionation also had a decisive influence. 50% of emergence was measured at the earliest for the C11, the latest for the C107 genotype (DAP 43. and 79.). The plants growing in a narrower plant distance, the 50% emergence ratio and the maximum emergence were generally reached 4–11days later than the plant grown under normal conditions. In the measurements of leaf height, fresh leaf weight, chlorophyll-a, -b and total chlorophyll content, according to genotype and plant number, the values of the C103 parent line and the C20 breeding line were in most cases significantly higher compared to the other two genotypes. As a result of the narrow number of plants, the tuber weight per unit area was significantly reduced in the observed parent (C103, a: 371.97 g/m2; C107, bc: 61.73 g/m2) and breeding lines (C20, b: 97.28 g/m2; C11, c: 2.13 g/m2). The higher number of seedlings and fractional planting resulted in significantly lower values in the weight of secondary tubers for genotypes C103 and C20, and when examining the distribution between fractions, we measured a statistically measurable difference for these two genotypes as well. Our results provide a good basis for learning the development processes of the potato genotypes included in the study and for the creation of breeding lines adapted to the extreme weather conditions of today, for the development of cultivation technology and seed production methods applicable to their specific characteristics.