XVI International Botanical Congess

Cultivated buckwheat (Fagopyrum esculentum) has distylous self-incompatible flowers and high genetic heterogeneity within cultivated varieties. Maintaining population vigor and trueness is therefore a challenge. In cultivation, cross-pollination is primarily accomplished by honey bees. The bees are inefficient (<5 compatible pollen grains per visit), and pollen tube growth rapid (20 min), so selection can be based on pollen-tube growth rates. High pollen loads increased seedling vigor. Heterostyly did not favor compatible pollination by honeybees, the two types of pollen were delivered in constant proportions. Embryo abortion was low for the first flowers and high in later flowers. In contrast, different pollen donors had equal success at paternity. Thus, selective abortion is mostly based on time of pollination rather than superior offspring genotypes.