Insect Pollination of Crops

Abstract

Plant species of economic importance are either self-fertile and set fruit or seed with their own pollen (self-pollination), or self-infertile and need to receive pollen from other plants of the same species (cross- pollination). Some self-fertile species are automatically pollinated with pollen from their own flowers (auto- pollination), but often the flowers are so constructed that either wind action or insects are needed to transfer pollen from their anthers to their stigmas. Moreover, self-fertile plants may produce more fruit, or seeds of better quality, when cross-pollinated than when self-pollinated, and various devices often favour cross-pollination to self-pollination even when the latter can occur. Basic experiments to determine the pollination requirements of a species are best done when possible in the still air of a greenhouse and the flowers either self-pollinated by-hand, cross-pollinated by hand, not pollinated by hand but shaken periodically to simulate wind action, or left alone, and the percentage of flowers that set seed, and the number and weight of seeds produced, determined for each treatment. Wind is the principal pollinating agent of agricultural grasses and a few other species, whereas most agricultural and horticultural crops that have conspicuous, coloured and scented flowers are adapted for insect pollination.