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Pollination of fruit trees is required to produce seeds with surrounding fruit. It is the process of moving pollen from the anther to the stigma, either in the same flower or in another flower. The morphology of flower petals often determines the type of pollination that will occur (wind or insect), as well as the morphology of the fruit that the flower will produce. Some types of flowers have the ability to pollinate through self-pollination, although many fruit trees require an insect pollinator.

The pollination process requires a carrier for the pollen, which can be animal, wind, or human intervention (by hand-pollination or by using a pollen sprayer). Cross-pollination between different flowers produces seeds with a different genetic makeup from the parent plants; such seeds may be created deliberately as part of a selective breeding program for fruit trees with desired attributes. Trees that are cross-pollinated or pollinated via an insect pollinator produce more fruit than trees with flowers that just self-pollinate. In fruit trees, bees are an essential part of the pollination process for the formation of fruit.

Pollination of fruit trees around the world has been highly studied for hundreds of years. There is a lot of information known about fruit tree pollination from temperate climates, but very little information known about fruit tree pollination from tropical climates. Fruits from temperature climates include apples, pears, plums, peaches, cherries, berries, grapes, and nuts which are considered dry fruits. Fruits from tropical climates include bananas, pineapples, papayas, passion fruit, avocado, mango, and members of the genus Citrus.

Apple
Most apples are self-incompatible, that is, they do not produce fruit when pollinated from a flower of the same tree and cannot be pollinated by the wind alone. A few are described as "self-fertile" and are capable of self-pollination, although even those tend to carry larger crops when cross pollinated from a suitable pollenizer. A relatively small number of cultivars are "triploid", meaning that they provide almost no viable pollen for themselves or other apple trees. Apples that can pollinate one another are grouped by the time they flower so cross-pollinators are in bloom at the same time. Pollination management is an important component of apple culture. Before planting, it is important to arrange for pollenizers - varieties of apple or crabapple that provide plentiful, viable and compatible pollen. Orchard blocks may alternate rows of compatible varieties, or may plant crabapple trees, or graft on limbs of crabapple. Some varieties produce very little pollen, or the pollen is sterile, so these are not good pollenizers. Good-quality nurseries have pollenizer compatibility lists.

Growers with old orchard blocks of single varieties sometimes provide bouquets of crabapple blossoms in drums or pails in the orchard for pollenizers. Home growers with a single tree and no other variety in the neighborhood can do the same on a smaller scale.

During the bloom each season, commercial apple growers usually provide pollinators to carry the pollen. Honeybee hives are most commonly used in the United States, and arrangements may be made with a commercial beekeeper who supply hives for a fee. Honeybees of the genus Apis are the most common pollinator for apple trees, although members of the genera Andrena, Bombus, Halictus, and Osmia pollinate apple trees in the wild.

In Japan, orchard bees are more commonly used, one species providing 80% of the apple pollination.

According to Christopher O'Toole's The Red Mason Bee, Osmia rufa is a much more efficient pollinator of orchard crops than the honeybee. Home growers may find these more acceptable in suburban locations because they do not sting. Some wild bees such as carpenter bees and other solitary bees may help. Bumble bee queens are sometimes present in orchards, but not usually in enough quantity to be significant pollinators.

Yet another kind of bee cultivated for orchard pollination is the hornfaced bee. It is used in Japan, and increasingly in the US, because it is up to 100 times more efficient than the honeybee, a mere 600 hornfaced bees being required per hectare, as opposed to tens of thousands of honeybees.

Symptoms of inadequate pollination are small and misshapen apples, and slowness to ripen. The seeds can be counted to evaluate pollination. Well-pollinated apples have best quality, and will have seven to ten seeds. Apples with fewer than three seeds will usually not mature and will drop from the trees in the early summer. Inadequate pollination can result from either a lack of pollinators or pollenizers, or from poor pollinating weather at bloom time. Multiple bee visits are usually required to deliver sufficient grains of pollen to accomplish complete pollination.

Pear
Like apples, pears are self-incompatible and need to attract insects in order to be pollinated and produce fruit. One notable difference from apples is that pear blossoms are much less attractive to bees due to their pale coloring and light odor. Bees may abandon the pear blossoms to visit dandelions or a nearby apple orchard. The majority of pollinators of pear trees are honey bees, although pears are also visited by blow flies and hoverflies. A way to combat the low attraction of honey bees to pear blossoms is to use bee attractants to entice the bees to pollinate the flowers. Bee attractants may include pheromones that mimic the brood pheromone or the juvenile pheromone, or other attractants. There are also other methods for attracting honey bees to pear blossoms. One is saturation pollination, that is to stock so many bees that all area blossoms are worked regardless of the attractiveness to the bees. Another method is to delay the movement of the beehives into the orchards until there is about 30 percent bloom. The bees are moved into the orchard during the night and will usually visit the pear blossoms for a few hours until they discover the richer nectar sources. The recommended number of hives per acre is one.