Great interest in viticulture in temperate climates results from the introduction of new interspecies hybrids of grapevines which are quite popular due to their high resistance to fungal diseases and lower temperature. However, the impact of rootstocks, common in vine cultivation, is little to not known, which makes setting up vineyards a challenge. This study aimed to evaluate the effect of the following six rootstock types: 101-14 Mgt, SORI, 161-49 C, 5 BB, SO4, 125 AA, and grapevines with their own roots on the yield quantity and berry quality (expressed by Brix extract) of Regent grapevines in temperate climates (southeastern Poland). A five-year experiment alongside a novel numerical model is applied to formulate precise and constructive findings about the rootstock impact in a temperate climate. Both the experimental and numerical part are supported by detailed statistical analysis. The five-year period of study indicates that the vines on rootstock 125 AA yielded the best, significantly. Shrubs grafted on rootstock 161-49 yielded the lowest, while the fruit extract content grafted on rootstock 101-14 was significantly lower among the evaluated ones. The parameters of own-rooted bushes and those grafted on SO4 rootstock did not differ significantly, except for the extract. The model leads to convergent conclusions with statistical analysis of raw experimental data. The 125 AA rootstock was the best for all nine tested case scenarios. On the other hand, 161-49 rootstock was the weakest, justified only in the most challenging conditions