Natural crossing of white clover by bees

ALTHOUGH an understanding of the mode of pollination is generally considered a prerequisite to the intelligent planning and pursuing of a profitable breeding program, detailed information on this subject has not been available previously for white clover (Trifolium repens L.). It has long been recognized, however, that honey bees are the most common pollinating insects for white clover and that seed set in the open is usually good if pollination has been adequately effected under proper environmental conditions. Since it was also known that most clones of white clover are self-sterile (9, 7, 2) it has generally been assumed that the species should be classed as naturally cross-pollinated under most circumstances. Though this assumption may hold for the majority of clones, the present study shows that it certainly does not apply to those bearing the self-compatibility factor (4)