Apple or Malus Domestica is one of the most cultivated tree fruit globally. Apples can be used in many ways, such as cooking, making cider, or even as desserts. There are so many varieties of apples, every one of them having a different shape, color, and flavor. Have you ever wondered how it’s possible to have so many variations of a single fruit?
Cross pollination is a way for growers to take the best of two varieties and breed them to produce a new variety. This also produces many new different flavours of apple!Keep on reading to find out how cross-pollination between apple trees happens. You can also pollinate apple trees yourself.
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What is Cross-Pollination?
Cross-pollination is the process of transfer of pollen from one flower to the pistils of another flower. Pollination occurs naturally with the help of many factors like wind, insects, water, etc. When the pollen from the male part of the flower is transferred to the stigma of the female part of the flower, pollination occurs.
Fertilization is followed right after, during which the flower grows into the fruit. The trees or flowers having the pollen are known as pollenizers, and the medium through which they get pollinated are called pollinators. These two play a really important role in pollination.
However, the same method of pollination isn’t suitable for all plant species. Sometimes it’s hard for a plant or tree to pollinate by itself. In that case, artificial cross-pollination is done. During artificial cross-pollination, the pollen is manually transferred to the other flower either of the same type or different.
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How to Pollinate Apple Trees?
Most commonly, pollination in apple trees occurs with the help of insects like bees. Bees come to the flower to flower to suck the nectar. In this process, they also transport the pollen from one flower to another, aiding in pollinating apple trees. Similarly, we can cross-pollinate different varieties of apple trees as well. As mentioned above, pollenizers and pollinators play a huge role in pollination, so the first step to pollinate different varieties of apple trees should be picking the best pollenizers and pollinators.
Picking the Best Pollenizer
You need to look for the following three things when choosing a pollenizer.
● First, you need to make sure that the pollenizer you picked blooms at the same time as the apple tree you want to cross-pollinate it with. For example, Royal Empire is an early bloomer, so if paired with Nittany, it’s a really bad option as Nittany is a late bloomer. However, Royal Empire is a great option for Liberty as they’re both early bloomers.
● Second, make sure your pollenizer is not triploid or pollen sterile. You will need two other trees to ensure good pollination for triploid pollenizers. Also, both of them should not be triploids themselves, making it tricky and hard to pollinate with triploid pollenizers like Bramley’s Seedlings, Ribston Pippin, etc. Pollen sterile means that they can be pollinated by other apple trees but don’t produce pollen themselves. So, they cannot be used as pollenizers, like Gravenstiem, Red Winesap, Jonagold, etc.
● Third, you can use a crab apple to pollinate apples provided that it has white flowers, as stated by North Carolina State Cooperative Extension. You don’t have to use cultivated apple trees to pollinate other apple trees.
Self-Fertile Apple Trees
Some apple trees are self-pollinating or self-fertile, which means that they can be pollinated by their own flowers or by flowers of the different trees of the same type. Though they can produce fruits by self-pollinating, the yields are often very low because usually apple trees are unable to self pollinate properly. The fruit quality of the yields is also very poor compared to the yields produced through cross-pollination.
Best Pollinators for Apple Trees
The most widely used pollinator for apple trees specifically is honey bees. Other than honey bees, mason bees and bumblebees can be used, though they’re not as common. These are bees that can be managed if a proper living space for them is provided.
For example, mason bees are solitary bees that prefer a hollow structure made out of cardboard or even paper straws. You can even make them at home by cutting pieces of bamboo or wood with pre-drilled holes. Mason bees are available in both native and non-native types used for orchard pollination. The most common species of native mason bees used for orchard pollination are called Osmia Lignaria or Blue Orchard. The most common non-native species are called Hornfaced bee or Osmia Conifrons.
Other than managed bees, wild bumblebees and other wild bees often visit and pollinate the apple trees. To encourage more visitations from wild bees, it’s advised to plant non-crop flowering plants near the orchard. Make sure to plant them in areas that are not exposed to pesticides.
How to do Artificial Cross-Pollination of Apple Tree?
Since self-pollinating is not always successful and not everyone can afford to buy bees to allow natural cross-pollination, you can also do artificial cross-pollination. It’s also called hand pollination. If your apple trees are not yielding enough fruit by natural cross-pollination, you should do artificial pollination to get good yields. You can follow the steps below to learn how to pollinate by hand.
● Use a cotton swab or a small paintbrush and swirl into an apple blossom or pollen package.
● Apply the cotton swab on the closest cluster of flowers or to all the flowers that are within reach.
● Repeat the process daily till the flower’s anthers brown and shrivel.
● The best time to pollinate is within the 12-72 hours of the flower opening, and the preferred temperature is 60-70 degrees Fahrenheit.
Most Compatible Apple Trees to Cross-Pollinate
If you want to pollinate apple trees, you need to plant a variety of pollinators, or you will end up having little to no fruit. There are many poor pollinators with apple plants, so you need to plant a good pollinator to ensure maximum yield.
Some poor pollinators include:
So, you should plant the crab apple variety with this type of variety to encourage cross-pollination.
Steps for Pollinating Varieties of Apple Trees
To get maximum yield, it’s important to make sure that you’re providing your apple trees with the best possible measures to pollinate. By following the steps below, you can learn how pollinating varieties of apple trees work.
● Plant a crab apple that has a blooming period similar to that of the existing tree within 50 feet of each other.
● Monitor the tree you plan on pollinating. If the pollen is transferring to your finger by a simple touch, they’re ready for pollination. If the flower’s stigma looks moist and sticky, it’s ready to receive the pollen for pollination.
● Look for the insect pollinators like bees and other insects. If they’re visiting the tree frequently, you may not need to do hand pollination. Cut the flowers of the tree you wish to pollinate and put them in a bucket of water. That will attract more bees allowing your trees to pollinate.
● If needed, then do hand pollination as explained above. Do it daily to ensure the successful pollination of apple trees.
Factors Affecting Pollinators and Pollination
Several factors reduce the rate of pollination, one of the most common being Pesticides. Learning about these factors is important because it can let you know why your apple trees have a lower yield than usual.
Pesticides or some Insecticides are harmful to pollinators. That is why many pesticides labels advise not to use pesticides during blooming season. Using pesticides during the blooming season will lead to a very low pollination rate. If there’s an absolute need for pesticides, they should be used very carefully, ensuring they don’t hurt the bees. For example, using them at night when the visitation from bees is the best idea as the pesticide will dry out before the bees can come back in the morning.
Stress from transportation is another very common factor affecting pollinators and ultimately affecting pollination. Over a million bees are transported from the United States to California alone. They are transferred in such a crowded environment with little to no ventilation causing them to die.
Less amount of pollinators than the planted trees can also affect the pollination rate. If there are many trees planted but fewer visits from bees and other pollinators, it will result in less dispersion of pollen to the stigma. So, if you’re managing an orchard with a large number of apple trees, make sure you also have enough pollinators to ensure successful pollination.
Apple trees can be found in many various types. To achieve different flavors of apples or different purposes, it’s important to understand how these apples are made. Cross-pollination is the process that allows us to enjoy many different tastes of a single fruit. Pollinating apple trees properly is the most important factor in getting good fruit yields. This article covers everything you need to know about how to pollinate apple trees, from what affects pollination to what you can do to maximize its yield.