ABSTRACT
Pollination biology is the study of the ways in which plants achieve pollination and the influence of the events of pollination on subsequent fertilization, seed production, and the progeny produced. The onion a plant only found today under domestication, is involved in a triangle of interactions involving two other vital components for its continued existence. Man, as the grower of the crop, maintains the onion as a valued food, and as seed production manager, selects from the population those plants which are to reproduce. The onion umbel is a roughly spherical inflorescence composed of numerous open, dishshaped flowers with easily accessible nectar, which attracts many types of unspecialized short-tongued insects. Onion pollen is bright yellow or green when first released but if left on the anthers, after 3 to 4 d it becomes faded and greyish. Onion pollen is simple in structure and lacks an elaborately sculptured exine, although it has a moderately sticky surface derived from tapetal breakdown products.
