Resumen
Climate change is being felt in all vineyards around the world, opening up new perspectives for regions with a growing winemaking industry. In this study, 11 hybrid grapevines grown in cold climates were assessed in terms of flowering biology and pollination efficiency. The flowers were evaluated for the number of anthers and pollen grains in the flower; pollen viability and pollen grain size, the number of ovules in the ovary, and, consequently, the size and the weight of berries and the number of seeds in the berries were also analyzed. The flowers of Vitis vinifera L. usually have 5 stamens and 5 petals in their structure; this number for hybrid varieties ranged from 4 to 7, and in the case of the variety ?Seyval Blanc?, it was 4 to 11 stamen and petals. Pollen grain size varied and ranged from 17.01 to 22.25 µm, while pollen grain pro-duction in flowers ranged from 5073 to 34,976 grain, which was calculated using a Bürker hemocytometer. The number of ovules in the ovary for the cultivars in question was highly variable, ranging from 3 to 7. One of the most important factors affecting flower pollination is stigma receptivity. Stigma receptivity appeared when the cap starts to fall off and disappeared at the browning of the cap. In connection with climatic changes, grapevine production is expanding to cool-climate countries. The aim of this study was to expand our knowledge about the flower morphology of 11 hybrid grapevine varieties most commonly cultivated in Poland. Knowledge of the flowering process can be important for improving yield and its quality.