Cross Pollination of an Avocado

About Avocado Trees

• Avocado trees come in three basic varieties, the Mexican, the Guatemalan and the West Indian. Each type has its own advantages for growing under certain conditions, such as salinity, cold tolerance and disease resistance. Avocado trees do not grow in poorly-draining soil or in flooded conditions. They are cold-tender plants that must be protected from sudden frosts and cold winds. Avocados grown from seed can take up to 15 years to mature and produce fruit, though they may not fruit the same as the parent plant. Most cultivated avocado trees are grafted seedlings that begin to produce fruit after two years. Trees produce yellowish-green flowers about 3/8 to 1/2 inch wide.

Cultivating Avocados

• To growing avocados, choose the proper varieties for your area. Consult with your local agricultural extension service for advice on pest and disease resistance. Stake new trees and set up shade cloth to prevent excessive sun exposure. Avocados require fertilization with 21-0-0 ammonium sulfate at the rate of 1/2 cup per plant during the first year, 1 cup during the second year and 1 1/2 cups during the third and successive years from February to September, according to Texas A&M University horticulturalist Julian W. Sauls. Water slowly and deeply rather than quickly and shallowly for best results. Hot, dry weather can affect tree health and fruit production. Preventing competition from weeds and grass is an important factor in establishing new avocado trees.

Pollination of Avocado Trees

• Avocado trees produce both male and female parts needed for pollination. These parts may function at different times of the day, however, according to University of Florida specialist Jonathan H. Crane. Planting of more than one type of avocado tree ensures that pollination occurs. Varieties are classified into "A" or "B" types depending on the time these reproductive parts operate. Different varieties of avocado may be self-pollinating or require cross-pollination from another type of tree. Wind and insects help to spread the pollen between trees.

Pollination Problems in Avocados

• Pollination problems in avocado are the result of not having sufficient types of trees in the area that will allow for transfer of pollen from the anthers of the plant to the stigma of the female plant. If there are no other avocado trees in the area, then both "A" type and "B" type trees must be planted to ensure cross-pollination occurs.