The effect of population density (50,000, 125,000, 200,000, 275,000 and 350,000 plants∙ha -1 ) was evaluated on Solanum tuberosum. L., variety 'Parda Pastusa', tuber yield at the Marengo experimen- tal station (Mosquera, 2,550 m.a.s.l.) and ICA San Jorge Centre (Soacha, 3,100 m.a.s.l.) in the Cundi- namarca department of Colombia by applying the Duncan's postulate. The competition among plants determined the answer of the tuber yield per plant and per hectare. In all the categories of the evaluated tuber they were relationships lineal negatives for the yield per plant in function of the density, it sustains the phenotypic plasticity of the yield in front of the vegetable spacing. The results allowed to confirm the postulate of Duncan (1958) that proposes that the yield average per plant decreases as consequence of the competition for resources of the ground and of the atmosphere. The results contribute work ele- ments and discussion so that starting from two densi- ties of evaluated plants, be considered the yields per plant and per hectare in potato crops.