Term (also erratic block) for the natural fertilisation of plant flowers, in English "open pollinated" (abbreviation O.P.). The stigmas of the flowers are "openly" pollinated, i.e. naturally by wind, insect or self-pollination (without artificial help from humans). If the grapevine seeds are sown later, then new descendants arise from them, whose pollen donor (father variety) is not known a priori. Cross-fertilisation with pollen from other varieties in the vicinity can occur through insects or wind, but also self-pollination (self-fertilisation). The father variety can only be assumed. open-pollinated contrasts with the deliberate crossing of new varieties, for which selected mother and father varieties are used and self-pollination is prevented beforehand by castration of the flowers (see also Flowering and Breeding).Actually, all grape varieties created by natural crossing without human influence are to be regarded as open-pollinated.