Apple

An apple is a deciduous tree grown for its fruits, known as apples. Apple fruits are one of the most widely cultivated fruits in the world. They are round (pome) in shape and range in color from green to red. The domestic apple tree is believed to have originated from Western Asia and the Mediterranean, having several wild ancestors. China is the largest producer of apples worldwide. Apple farming can be profitable and rewarding for farmers with suitable land, climate, and markets.

Crop Details

Scientific Name: Malus domestica

Common Name: tufaha (Sw), apple tree (En), manzano (Sp), pommier (Fr) 

Ripe apples on tree

Young fruits beginning to develop

Apple tree

Apple blossoms

Apple fruits ripening on the tree

Apples are most commonly eaten fresh but can also be used for baking and cooking. They can be processed into applesauce, cider, vinegar, juice, or butter. Slices can be dried for later consumption. Apples can also be used for the extraction of useful compounds such as fructose and pectin. Apples are rich in fiber, Vitamin C, minerals, and antioxidants. 

Apples are a great source of soluble fiber, which can help reduce intestinal disorders. They also aid in controlling insulin levels by slowly releasing sugar into the bloodstream. Additionally, apples can lower cholesterol levels and reduce the risk of respiratory diseases. They are also known for their ability to detoxify and cleanse the body. Furthermore, apples have been traditionally used to treat conditions such as fever, dysentery, diarrhea, and constipation.
 

There are thousands of apple varieties available around the world, and each one has its own unique characteristics such as size, color, shape, flavor, texture, ripening time, storage life, and disease resistance. Apple varieties can be broadly classified into three categories: (1) cider varieties, (2) cooking varieties, and (3) dessert varieties. These categories differ in various aspects such as color, size, aroma, smoothness, crispness, and tang.

Some of the most commonly known apple varieties are Red Delicious, Golden Delicious, Gala, Fuji, Granny Smith, Honeycrisp, Braeburn, McIntosh, Jonagold, and Pink Lady.

Basic Requirements

Apple trees grow best in the tropics and at higher latitudes. They require a mild growing season and a cold winter to break their dormancy. In these latitudes, the tree will flower in spring and the fruit will ripen in the fall. In the tropics, the leaves will remain on the tree longer, making it essentially evergreen, and flowering and fruiting will happen sporadically throughout the year unless the tree manages to enforce a uniform cycle across the entire tree by bending shoots to create a wide tree.

Apple trees require fertile, well-drained, and well-aerated loamy-sandy soil, with a slightly acidic to alkaline pH of 5.5-6.5. You must test your soil before planting and amend it with organic matter, lime, or sulfur if necessary. Apples require a lot of moisture during the flowering and fruiting stage. Therefore, if you are growing apples in hotter regions, you will need to irrigate your trees. However, keep in mind that excess water around the root zone will encourage disease outbreaks and result in low crop yield. The best method of irrigating apples is through drip irrigation.

Growing from Seed

When planted from a seed, an apple tree can take six to ten years to mature and produce fruit of its own. Apple trees are small to medium-sized, reaching heights of 5–10 m (16.4–32.8 ft), with a central trunk that divides into several branches. The leaves of the tree are oval in shape and can reach up to 13 cm (5.1 in) in length and 7 cm (2.8 in) in width.

The standard method of propagating apple trees is by budding. When planting an apple nursery or orchard, it is highly advisable to plant seedlings budded from rootstock to prevent an increase in bud dormancy. Budded trees should be pruned in the first year to encourage new shoot growth.

Apple trees can also be propagated by grafting and mound layering. Grafting involves joining the lower part of one plant (rootstock) with the upper part (scion) of another. Grafting is usually done during the dormant season and must be performed on dormant scion and stock wood.

Mound layering is used to propagate apple clonal rootstocks. Soil is mounded around shoots that have been cut back, thereby stimulating roots to grow at the base of the shoots. A year before propagation begins, 8–10 mm (0.3–0.4 in) diameter stock plants are planted in rows and then cut back to 45–60 cm (17.7–23.6 in). They are then grown for one year.

In the spring, the plants are again cut back, this time to 2.5 cm (1 in) above the ground. New shoots gradually form, and more soil and bark are added in mounds around the plants. This cycle can continue throughout the growing season. Then the shoots are harvested by cutting close to the bases. The mother stool beds are then left exposed until further growth of the new shoots has occurred, and another cycle of hilling begins.

Apple seedlings are planted with a depth of 10-12 inches and spaced 8-10 feet apart in rows.

General Care and Maintenance

In the tropics, apple trees require careful management to make heavy crop loads sustainable. This includes bending shoots, pruning the tips, and defoliating the trees. Flowers are also removed to promote growth until the first fruit production, generally after 2 years.

Harvesting

An apple is ready for picking when its background skin color turns from green to yellow. The fruit comes off easily when harvested. Harvesting apples at the right time is key, not only to obtain the highest quality fruit but also to maximize the storage life.

Maturation time is dependent on weather conditions during the growing season. Early maturing apples are harvested in August-September.

There are several reasons why proper picking technique is important. First, simply pulling apples from the tree with force is likely to bruise the fruit and remove the stems. Apples without stems do not store as well as apples with stems.

Second, it is easy to identify apples that have been picked incorrectly. They will have noticeable fingerprint bruises. Make sure to palm instead of grab when picking. Yanking tends to remove spurs from the tree. These fruit spurs represent next year's crop, so by pulling them off, there will be fewer apples to harvest next year. In addition to not pulling the apples from the tree, there are some other actions that are important to avoid.

Apples that have touched the ground are a potential source of contamination. Never mix apples from the ground with picked apples. Apples that are decaying or rotten should be dropped on the ground and never placed in your bin. Do not throw or drop apples into your bucket, as this will certainly cause bruising. And always avoid squeezing the fruit when picking.

CABI Crop Protection Compendium. (2013). Malus domestica datasheet. Available at: http://www.cabi.org/cpc/datasheet/31964. [Accessed 05 November 14]. Paid subscription required

Peck, G. M. & Merwin, I. A. (Eds) (2009). A Grower's Guide to Organic Apples. Cornell Cooperative Extension. Available at: nysipm.cornell.edu/organic_guide/apples.pdf. [Accessed 05 November 14, link broken Nov 2 2018]. Free to access

Polomski, B. & Reighand, G. (2007). Home and Garden Information Center: Apple. Clemson Extension. Available at: http://web.archive.org/web/20060907110823/http://hgic.clemson.edu/PDF/HGIC1350.pdf. [Accessed 05 November 14]. Free to access

Sutton, T. B., Aldwinckle, H. S., Agnello, A. M. & Walgenbach, J. F. (Eds.) (2014). Compendium of Apple and Pear Diseases and Pests. 2nd Edition.

American Phytopathological Society. APS Press. Available at: http://www.apsnet.org/apsstore/shopapspress/Pages/44303.aspx Available for purchase from APS Press

Warmund, M. (2014). Home fruit production: apples. University of Missouri Extension. Available at: http://extension.missouri.edu/explorepdf/agguides/hort/g06021.pdf. [Accessed 05 November 2014]. Free to access