APPLE PROPAGATION

Apple Propagation

Introduction:

Apples (Malus domestica) are one of the

oldest fruit crops grown around the world.

They have been a resident of the

United States since the first settlers founded

the Jamestown colony in 1607. Since then,

the apple industry has grown immensely. It

is now the third most valuable commercial

fruit crop, and is essential to several state

economies, specifically Washington and

Pennsylvania. The fruit is used extensively in

food and beverage preparation and makes

for a great, healthy snack when eaten fresh.

With many health benefits, an apple a day

can truly keep the doctor away. Also, the

blossoms can be used in honey production.

There are thousands of cultivars available for

the commercial grower. Apple production, however, does not require expertise knowledge. Many homeowners can grow and propagate their own apple trees to enjoy the benefits of the wonderful apple.

Propagation:

Methods:

Apples are not usually propagated by seeds as the seeds will not grow to produce the same apple tree. Desired genes, specifically the ones influencing fruit quality, will be lost due to the genetic recombination that occurs during the seed forming process. Apples are not usually propagated through cuttings because these are hard to root (Hartmann; et al., 742). Apples can be propagated through tissue culture; however, this is not common because of the high costs involved. The two main propagation methods practiced today when propagating apples are grafting and budding. Grafting and budding are both acts of joining two plants so that will continue to grow as one (Hartmann; et al., 417). Grafting and budding have many advantages. The most important, with regards to apple propagation, are that tree sizes can be controlled through dwarfing rootstocks, ideal genes are preserved, genotypes can be combined, and that the time it takes for a tree to reach maturity is greatly reduced. Both grafting and budding are used frequently in apple propagation, however, grafting is usually the chosen method due to its higher success rates. A grafted tree consists of two components. The wood above the grafting site is called the scion. Possessing buds, this will turn into the branches of the tree and produce the apples. The second is called the rootstock. Possessing roots, this becomes the root system of the tree. Each component contributes favorable genes to produce a superior tree that will be resistant to many kinds of stresses and produce good quality fruit. Two of the most commonly used grafting techniques in apple production are whip and tongue and cleft grafting. Whip and tongue grafting is commonly used to start new trees. Cleft grafting is commonly used for topworking, which is the act of changing an apple tree’s cultivar.

Step by Step Procedure for Whip and Tongue Grafting:

Choosing the Scion:

Start collecting scion wood during the dormant season (February through late March)
When choosing the scion to use, it is important to look for certain qualities to ensure the scion will successfully grow. Make sure the plant contributing the scion wood is healthy and free of diseases.
Verify that the scion wood contains a few buds (around 3-7 will suffice). Also be sure to only take terminal twigs of the previous season’s growth. These twigs should be smooth, straight, and about pencil thickness.
Be sure to choose scions from trees that will yield good quality fruit. Qualities such as appearance, flavor, versatility, and popularity should be considered when choosing a cultivar. Disease resistance should also be considered.
Once selected, cut the scions, then wrap them in a damp paper towel or sphagnum moss to prevent desiccation.
Place these scions into a bag and place the bag in a refrigerator. This will ensure the scions remain dormant.
These steps are the same regardless of which type of grafting is used.

Choosing the Rootstock:

Rootstocks are very diverse and there are many different varieties. Growing rootstocks from seed can be very complicated. When choosing a rootstock, it is easiest to decide on the rootstock’s desired qualities, and then order it from a certified supplier.
To decide on the best qualities of the rootstock, look for rootstocks that will restrict the tree to a manageable size, if the tree is too large, it cannot be easily maintained.
After this, look for rootstocks that are resistant to many biotic and abiotic stressors. These include resistance to major diseases and resistance to drought and/or excessive moisture.
These steps apply to whip and tongue grafting only. Cleft grafting is only used on established rootstocks. The rootstocks used must be dormant for both methods.

Completing the Graft:

Whip and Tongue Graft:

Before beginning, check the polarity of your scion and rootstock. The roots of the rootstock should be at the bottom, and the scion should be positioned so that the uncut end is at the top.
The rootstock and scion should be about the same thickness. If the rootstock is slightly larger in thickness, do not worry, this can be compensated for later.
Be sure to also use a sharp, grafting knife so that clean, straight cuts can be made. Please exercise caution as these cuts are designed to be made towards yourself.
Begin grafting in late March through mid April. To begin the whip and tongue graft, make a downward sloping cut about 1-2 ½ inches long at the top of the rootstock. Make this cut on the rootstock at a spot so that when planted, the graft union site will be about 2-4 inches above the ground.
Next, make another downward sloping cut that is ½ the length of the previous cut. Start this cut about 1/3 of the way down from the tip of the previous cut. Also, make this cut at a slightly deeper angle.
Repeat steps 4 and 5 at the bottom of the scion.
Join the scion and rootstock together. This step is critical. The cambium tissue of the rootstock and the cambium tissue of the scion must be mostly aligned. If not, the graft will fail. If the rootstock and scion are almost the exact same diameter, then no adjustments will be needed. If the rootstock is slightly larger than the scion, align the cambium layers on one side of the graft.
Once properly aligned, wax the graft union using grafter’s wax, or wrap the union with parafilm. Both methods create a seal protecting the graft union from desiccation and disease.
Place the newly grafted tree or trees in a cool, moist room (approximately 40º F) for 7-14 days to allow the cambiums to produce new plant cells to heal and join the scion and rootstock together. If possible, try to keep the graft union warmer, but this is not necessary.
Plant the tree or trees in pots before the buds expand. Signs that the graft took would be new growth in the scion. If any suckers form at the base of the rootstock, remove them so that all of the nutrients are diverted to the scion.
Once a fairly vigorous root system has developed, transfer the tree or trees to their permanent location. Also when callus tissue has formed, remove the wax or parafilm from the graft site.
Congratulations! You have successfully grafted new apple trees!

Cleft Graft:

Before beginning be sure to check polarity of scion. The scion should be positioned so that the uncut end is at the top.
Since the rootstock is already established, this method is easier than the whip and tongue graft described above. Also it is important to note that this is usually done on rootstocks that are about 1-4 inches in diameter (Hartmann; et al., 472).
Cleft Grafting is done in early spring, around early April. To begin, select the apple tree you wish to top work and cut the tree down leaving about 6-12 inches of the rootstock above the ground. Cut this squarely and cut completely through the tree. Do not let the tree fall on its own. This will cause the cambium to split on one end of the rootstock.
Take a wedge shaped object, like an axe head or a butcher’s knife, and line it up so that when it is pushed into the rootstock, it will split the rootstock in half. The lightly pound the tool 2-3 inches into the rootstock using a hammer.
Use a smaller wedge, such as a screwdriver, to keep the spit area open. Take the two scions (4-6 inches in length) to be used and make a single, smooth, sloped cut on each end. Cut at a deep enough angle to ensure the cuts come to a point at the bottom of the scion.
Insert these scions into the split area. Be sure to align the cambium tissues.
Remove the smaller wedge and coat the entire cut rootstock surface with grafting wax.
When new growth is observed in the scions, it is best to remove all but one of the other branches attached to the base of the rootstock. The one limb leftover will serve as a nurse limb.
Congratulations! You have successfully cleft grafted your apple tree.

Conclusion:

By utilizing these grafting methods, the average homeowner can easily produce apple trees for their own personal pleasure. With practice, one can easily master these techniques. After only a handful of years, these new trees will produce wonderful, delicious apples that can be used for many different purposes. With around a thousand cultivars to choose from, the hardest part about apple propagation is figuring out which apples you want to grow. For more information on apple propagation, feel free to check out the references listed below:

References:

Crasweller, R.M. Grafting and Propagating Fruit Trees. Penn State Extension. College of Agricultural Sciences. The Pennsylvania State University. Published in 2005. Retrieved From: http://extension.psu.edu/publications/uj255. Accessed on April 4, 2016.

Hartmann, Hudson T., Dale E. Kester, Fred T. Davies, and Rovert L. Geneve. Hartmann & Kester’s Plant Propagation: Principles and Practices. 8th ed. Boston: Prentice Hall, 2011. Pages 417, 472, and 742. Print.

Lord, William G. “Grafting Apple and Pear Trees in the Home Orchard”. University of New Hampshire Cooperative Extension. Published in November, 2013. Retrieved From: https://extension.unh.edu/resources/files/Resource003733_Rep5323.pdf. Accessed on April 4, 2016.

Miller, Diane Doud. “Apple Tree Propagation: Grafting”. Cooperative Extension System. Published on August 14, 2013. Retrieved From: http://articles.extension.org/pages/60602/apple-tree-propagation:-grafting. Accessed on April 4, 2014.

Synan, Mariel. “All About Apples”. History. A&E Networks Corporation. Published on September 13, 2013. Retrieved From: http://www.history.com/news/hungry-history/all-about-apples. Accessed on April 4, 2016.