Apple - Malus domestica
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TAXONOMY

The cultivated apple, Malus domestica Borkh., belongs to the Pomoideae subfamily of the Rosaceae, along with pear (Pyrus spp.), quince (Cydonia oblonga), loquat (Eriobotrya japonica), and medlar (Mespilus germanica). 

Cultivars   Top ten apple cultivars grown in the United States, 1997. Data are in thousands of boxes (42 lbs of apples/box).
 
Cultivar 1993-97  

5-yr average

1996 1997 % change 1996-97
Red Delicious 105,722 103,969 95,709 -8
Golden Delicious 36,710 35,712 35,725 0
Granny Smith 16,598 16,030 16,607 +3
Rome 15,978 13,624 14,720 +8
Fuji 10,648 12,692 16,205 +28
McIntosh 12,647 11,195 13,253 +19
Gala 7,036 8,149 9,870 +22
Jonathan 6,519 4,634 5,748 +24
Idared 4,899 3,987 5,097 +28
Empire 4,127 4,377 4,964 +14
All others 35,184 32,179 35,645 +11
 
 

ORIGIN, HISTORY OF CULTIVATION
 The center of diversity of the genus Malus is the eastern Turkey, southwestern Russia region of Asia Minor. Apples were probably improved through selection over a period of thousands of years by early farmers. Alexander the Great is credited with finding dwarfed apples in Asia Minor in 300 BC; those he brought back to Greece may well have been the progenitors of dwarfing rootstocks. Apples were brought to North America with colonists in the 1600's, and the first apple orchard on this continent was said to be near Boston in 1625. From New England origins, apples moved west with pioneers, John Chapman (alias Johnny Appleseed) and missionaries during the 1700's and 1800's. In the 1900s, irrigation projects in Washington state began and allowed the development of the multi-billion dollar fruit industry, of which the apple is the leading species.
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PRODUCTION

World (2004 FAO) - 59,059,142 MT or 130 billion pounds. Apples are produced commercially in 91 countries on about 13 million acres. World apple production has increased about 17% in the last decade. Average yields are 10,000 lbs/acre worldwide, but averages of over 40,000 lbs/acre are achieved in New Zealand.
 
Top 10 countries
(% of world production)
1. China - 36% 6. Italy - 4%
2. USA - 7% 7. Poland - 4%
3. Turkey - 4% 8. Russia - 3%
4. France - 4%  9. Germany - 3%
5. Iran - 4% 10. India - 2%

United States (2004 USDA) - 4.6 million MT or 10.1 billion lbs. Apples are grown commercially in 35 states. The value of the industry is $1.76 billion. There are approximately 8,000 apple growers in the USA, who on average receive prices of 19 ¢/lb. Apple acreage is currently 386,000, and yields average over 26,000 lbs/acre, more than double the world average.  Leading apple states (in order): WA, NY, MI, CA, PA.

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BOTANICAL DESCRIPTION

Plant  3.3 royal gala

Small to medium sized tree with spreading canopy, to 30 ft in wild, generally 6-15 ft in cultivation. Tree size and shape is heavily dependent on rootstock and training system (see below). Leaves elliptical with serrate margins, dark green with light pubescence on underside.

Flowers
 
Petals are white when open, but have red-pink undersides when opening, hence the "pink" bloom stage. The ovary is inferior, embedded in the floral cup or hypanthium, containing 5 locules, usually 2 ovules per locule. The inflorescence is a cyme of 4-6 flowers, with the center flower opening first; the central flower is often called the "King bloom", and has the potential to produce a larger fruit than other flowers. Flowers are produced terminally from mixed buds (containing both leaves and flowers) on spurs, or to a lesser extent on long shoots. Spurs form on 2-yr-old and older wood, and generally grow only a fraction of an inch each year. 

3.4 apple cyme3.4 king flower




Pollination

Most cultivars are commercially self-unfruitful. Cross-incompatibility is rare, and most cultivars that bloom at the same time and are not sports of each other will serve as pollinizers, including crabapples. Single apple trees produce some fruit when self-pollinated because most cultivars are not totally self-incompatible. A few cultivars are pollen-sterile (e.g., 'Jonagold', 'Winesap', and 'Mutsu'). Honey bees are the most effective pollinator.

Fruit
 
A special fruit type is given to apple and related fruits - the pome. The bulk of the fleshy edible portion derives from the hypanthium or floral cup, not the ovary. Seeds are relatively small and black, and mildly poisonous. Fruiting begins 3-5 years after budding, although a few fruit may be produced in the 2nd year. This varies with rootstock (dwarfing = more precocious) and cultural practices (excessive pruning = delay). Fruit are usually thinned to 1 per spur, with spurs spaced 4-6 inches apart for attainment of marketable size. Apples are generally thinned with chemicals such as the insecticide Sevin, or the synthetic auxins NAA and NAAm.

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GENERAL CULTURE
Soils and Climate

Deep, well-drained, loamy soils with pH 6-7 are best, but apples are grown on a wide variety of soils worldwide.
  3.6 prosser orchard
Apples are adaptable to various climates, but can be considered best adapted to the cool temperate zone from about 35-50° latitude. They have a more northern range than many other tree fruits due to relatively late blooming and extreme cold hardiness. Apples reach maturity about 120-150 days after bloom, with some cultivars maturing in as short as 70 days, and others as long as 180 days.

 Propagation

 T- or chip-budded in the nursery, and sold as 1-year-old whips on 1.5 to 2-year-old rootstocks.
 
3.7 apple chip buds















Rootstocks
                                                                    Some popular apple rootstocks and their characteristics.


Susceptibility b

Rootstock Size  
Reduction
Crown Rot Fire Blight Cold Damage Precocity Induction
M.27 25 1 3 3 High
Budagovsky 9 30 1 3 1 High
M.9 35 1 4 3 High
M.26 40 3 4 1 High
Mark 40 2 3 1 High
Ottawa 3 40 1 3 1 High
M.7 65 2 1 1 Medium
MM.106 75 4 2 2 Medium
M.2 80 2 2 1 Medium
M.4 80 1 2 2 Medium
MM.111 85 2.5 2 1 Low
Merton 793 95 2 ... 2 Medium
Domestic Seedling 100 2 2 1 Low
Maruba 110 1 1 ... ...
Novole 110 1 1 2 Medium
                                                                  [Modified from Westwood's Temperate Zone Pomology 1993].
                                                        a Tree size as percentage of size trees on domestic seedling rootstock.
                                                        b Increasing susceptibility from 1 or 4.
 
Planting Design, Training, Pruning
 
Planting Design: rectangular arrangements or hedgerows; spacings vary by rootstock (see below). Tree densities of over 1000 trees/acre are used in some areas of Europe.  Training systems are highly variable; central leader is most common. Pruning: late winter, severity and type of pruning cuts depend on bearing habit, fruit size, inherent tree vigor, and training system.

Rootstock  Between trees in row (ft) Between rows (ft)
Non-spur scion Spur scion Non-spur scion Spur scion
Seedling 18 12 22 18
MM.106 16 10 20 16
MM.111 16 8 20 14
M.7 12 8 18 14
M.26 10 6-8 16 10-12
M.9 8 6-8 14 10-12
 

3.10 slender spindle apple bolzanoA spindlebush apple tree is just a variation on the theme of central leader (left). A small central leader tree is trained using a metal post for support; the lower tier of scaffolds has formed (center). 'Gala' apples fruiting in their 2nd year in the field trained to an intensive trellis system (right).
3.10 1yr central ldr staked
3.10 2nd leaf gala nz

HARVEST, POSTHARVEST HANDLING

Maturity
 
Several methods are available for determining optimal harvest time. Days from full bloom is relatively constant from year-to-year, and gives growers a rough estimate of picking date. Cultivars like 'Gala' mature early and 'Fuji' very late. Target values of firmness vary by cultivar and intended storage method, with firmer fruit reserved for long-term storage.
 

Harvest Method

Apples must be picked by hand to avoid bruising and reduction of fresh market quality grade. Fruit must be picked carefully to avoid damaging the spur, where next season's fruit will be borne.

Postharvest Handling

Standard packing line operations are used for apples after harvest - hydrocooling, washing, culling, waxing, sorting, and packing (Figure 12). Apples are packed most often in 4/5 bushel boxes (40 lbs), but polyethylene bags (5-10 lbs) are also popular for retail marketing. Quality grade is based on size and appearance of skin; greater prices are obtained for larger fruit and those with minimal surface blemishes.

Storage
Controlled atmosphere (CA) storage has allowed the marketing of apples on a year round basis. The storage room atmosphere is altered to retard respiration by reducing oxygen to 2-3%, and raising CO2 to about 1%. Firmer, less ripe fruit are placed in long-term CA (150-365 days), while more mature fruit are sold directly or placed in short-term storage.

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CONTRIBUTION TO DIET
 

Apples have a broad spectrum of food uses: pies and cakes, jams, sauces and juices, apple butter, dried apples, and much more. Apple juice has surpassed orange juice consumption by children in the USA. A medium-sized apple contains about 80 calories, and is unusually high in fiber: generally about 5 grams per fruit (mostly from pectin). In 2001, United States consumers ate an average of 45.2 pounds of apples and processed apple products. About 60% are eaten fresh (about 60-70 apples, or more than 1 per week). The utilization is as follows:
 
Fresh - 55-60%
Canned - 12-15%
Dried - 2-3%
Frozen - 2-3%
Juice, cider, sauce, vinegar, other - 20-25%

Dietary value, per 100 gram edible portion
 
Water (%)  85
Calories
56
Protein (%) 
0.2
Fat (%)
0.6
Carbohydrates (%)
14
Crude Fiber (%)
3-4

% of US RDA*
Vitamin A
1.8
Thiamin, B1 
2.1
Riboflavin, B2
1.2
Niacin
0.6
Vitamin C
16
Calcium
0.9
Phosphorus
 1.2
Iron 
3.0
Sodium
---
Potassium
2.3
 * Percent of recommended daily allowance set by FDA, assuming a 154 lb male adult, 2700 calories per day.
 
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