PERENNIAL TEMPERATE FRUITS



OUTLINE:
Reading
CHAPTER 3 IN TEXT (p. 53) read pgs. 12-20

Introduction
Contrast fruits with cereal grains and legumes
Economics of cultivation
Preservation drying cold storage jellies etc.

Most important Fruits
Rosaceae
Apples - pomes - see pp. 57-64 - 50% of all fruit production
Prunus- drupes - plums (prunes), peaches, cherries, apricots
Vitaceae
grapes - berries
Nuts
Juglans regia(walnut)
Prunus amygdalus(almond)

Types of fruits.
The term "fruit" means different things to different people. To botanists the term means a matured ovary along with its contents and any adhering accessory structures. Green beans, cucumbers and squash are fruits. Tomatoes and eggplants are fruits. Fruits usually include seeds. In some instances, however, fruit and seed development can occur without fertilization. A fruit that develops without seed formation is called "parthenocarpic". In some cases plants that set fruit of this type have been selected because they mature fruits spontaneously without fertilization.
Fruits are often classified by the number of ovaries which are involved in their formation, by the position of the ovary (superior or inferior), by whether the fruit is dry or fleshy at maturity, and by the way it releases its seeds (dehiscence).
Table 3-1, p. 54, in the text outlines this.
GO OVER THIS TABLE (pg. 54)
Simple fruits have seeds surrounded by three layers: the endocarp, mesocarp, and exocarp. SEE FIG. 3-3, pg. 57. Simple fruits can be indehiscent or dehiscent. Dry fruits and their seeds are usually dispersed by wind, water, or gravity. In grains or caryopses the seed coat is fused to the ovary wall.
In other fruits, the pericarp layers are fleshy. If the fruit is produced by a single superior ovary within a flower, the fruit is a berry. Berries may contain one or more seeds. If the seed is enclosed in a hard endocarp, the fruit called a drupe. Citrus fruits have a special type of berry with a leathery rind, oil glands, and specialized fleshy hairs.
If the ovary is inferior, other floral parts are attached to the ovary wall. The fruits are often called accessory fruits. Many are still called berries. Those of the squash family are called pepos.
If there are numerous, simple, superior ovaries within a single flower, the fruit is called an aggregate fruit, e.g., blackberries.
Multiple fruits involve fusion of many fruits from numerous separate flowers.

Composition of fruits
Fleshy fruits have evolved to attract animals that eat them and disseminate the seeds. The fleshy part tends to consist of flavored sugar solutions without too many nutrients. The avocado and olive are exceptions. Fruits are good sources of water soluble vitamins. See table 3-3, p. 60.
Seeds are quite different in composition. They usually have fats, oils and/or starches. They are often protected by hard shells, seed coats, and toxic compounds. They are usually high in nutritional energy. See table 3-4.
These fruits are preserved by drying, cold storage, as jellies, preserves or sugared, smoking or freezing. Most are consumed raw. They are never basic to the diets of any groups of peoples, but are important in many, especially in the Middle East, for example.

Domestication of fruits.
Although most of these crops (that is, plants related to the ancestors of most of these crops, occur in both the Old and New World, the crop plants were almost all domesticated in the Old World. A few New World ones have been domesticated in the last 200-300 years (e.g., the blackberry and the cranberry). These and many other similar fruits have been used by hunter-gatherers up to the present.
All are slow growing perennials and selection has not changed most of them significantly with the exception of larger fruits etc.
Most are still hand harvested. Where they are grown is largely dependent on where labor is cheap.

Apples
Apples are the most important temperate fruit tree in the world. Apples and their relatives pears, peaches, plums, cherries, strawberries, blackberries, etc. all come from the rose family, the Rosaceae. There are several types of fruits in this family.
Apples are called "pome" fruits because of the special type of fruit they have. See page 57-64 in the text.
The genera Malus, Pyrusand Cydoniaall belong to the same subfamily. Apples account for 50% of the world's deciduous fruit tree production. The genus Malus probably arose in Asia but spread to the Americas long before any human came to this continent.
All cultivated apples are native to the Old World. They probably came from the Caucasus Mtns.
Good apple cultivars are mostly cultivated by grafting. We eat the "floral cup" of the apple.
World production of fruits SEE TABLE 3-5 ON PG. 62-63.
Note that large countries almost always lead in production of plant products. They may be relatively more important in small countries or regions of a large country however. Compare top 5 countries and top 5 continents. Fruit crops usually require lots of inexpensive labor to be competitive. Again look at the table.


Apple blossoms

Pears
Pears are probably the second deciduous tree fruit crop.
The pear may have arisen in sw Asia or in China or both. None are native to the New World. Pears usually propagated by grafting. Both quinces and pears are more popular in Europe than in the U.S.

Fruits from the genus Prunus
Several important fruits belong to this genus. Among these are plums, cherries, peaches, and apricots. The fleshy mesocarp is eaten. The fruits are drupes. Most of this group seems to have arisen in central or western China. There are wild species of cherries and plums in the New World as well.
These plants have been cultivated for at least 2000 years.
Prunes are dried plums. This was formerly the major method of preserving fruit. Otherwise they would only be available in season.
Many of these plants are grown as ornamentals and not for their fruits. Peaches are the third most important fruit crop in the U.S. (apples, oranges, peaches). They are also usually propagated by grafting.
Apricots first brought to Greece from Persia by Alexander the Great. They were brought to the New World by the Spanish.

The "Berries" of the fruit trade
Strawberries, blackberries, raspberries are not berries. Most of the strawberry is the receptacle on which the ovaries are born. Strawberries native to both the Old and New World. Fragaria virginianain eastern North America most common. F. chiloensisfrom Chile. These two species hybridized in a botanic garden in Europe about 1750 to produce the commonly cultivated strawberry today (F.ananassa).
Members of the genus Rubus are also native to both the Old and New World. Representatives of both are cultivated.

Currants and gooseberries
Both Ribes(Grossulariaceae). Much more common in Europe than here. Occur in both New and Old World.
Blueberries and cranberries
Both belong to the genus Vaccinium(Ericaceae). This group native to North America and introduced into Europe.

Grapes
One of the most important fruit crops in the world. Will be discussed as a source of alcoholic beverages later. Vitis vinifera(Vitaceae) is the most commonly cultivated species. Many table grapes produce poor wine and different grape cultivars are usually used for beverage production.
The most important New World grape is V.lambrusca. Concord and Catawba grapes belong to this species.
Raisins are dried grapes. Again, this was formerly one of the major ways of preserving fruits. Fossils of grapes known from Europe. They were cultivated by 5000 B.C. in India and in S.E. Europe. In North America they were widely eaten by the Indians (but not cultivated). Disease problems will be discussed later. Grape production in California is highly mechanized.

Grapes-Vitis vinifera

Olives
Olives have been an important food and source of oil for more than 5000 years. Olea europaea (Oleaceae) is native to the area at the east end of the Mediterranean Sea. They still grow wild there. Olive seeds have been found back as far as 3000 B.C. Fresh olives are extremely bitter and must be detoxified.
Olives processed by drying, salting, and pickling. Only about 1-2% of the olive crop is eaten as a fruit.


Olive flowers

Temperate nuts
One seeded, indehiscent fruit, usually quite hard. In the botanical sense, acorns and hazelnuts are true nuts. Typically high in protein and lipid. Usually hand harvested. Domestication - also slow growing and frequently vegetative reproduction. Used in all cultures, but not major in any today. Many nut crops are grown on arid, agriculturally marginal lands where labor is cheap.
The major nut crops are: walnut (English), almond, and cashew (discussed under next topic). Ranking should consider both tonnage and dollar value.
From the archaeological record, it is clear that many nuts were eaten in the past. Acorns and hickory nuts were the major food plants of many American Indian groups of the eastern U.S. and also of California along the west coast.
Acorns are still used as a food by poor people along the Mediterranean in Europe.
Walnuts, pecans, almonds, chestnuts, filberts or hazel nuts are native to temperate regions of the world. Pecans are the only nut to come from the New World. Peanuts are native to the South American non-center (discussed under legumes). In contrast to the fruits above, nuts are dry fruits. In addition, the edible portion is the embryo which has enlarged cotyledons. See table 3.4, p. 60, for nutritional information.


Acorns

Pecans and walnuts
The English walnut (Juglans regia, Juglandaceae) (native to Iran) is the most important of these. In the United States, most walnuts are grown in California. Rich in oil.
The pecan (Carya illinoensis) is native to North America. Native to south central U.S. and Mexico. "Paper shell" varieties now often cultivated. Pecan orchards common in the south, e.g., in Texas, Oklahoma, Georgia etc. Some in Australia and S. Africa.
The black walnut (Juglans nigra) is also native to North America, but is relatively unimportant.
Hickory nuts (Caryaspp.) belong to the same family. They were formerly eaten by many North American Indians, but are relatively unimportant today.


English walnut

Almonds
Almonds (Prunus amygdalus, Rosaceae) belong to the same genus as the fruit crops we just discussed. The removal of the leathery mesocarp leaves the seed inside the endocarp. The seeds of some cultivars are highly toxic. Sweet and bitter almonds. Almonds were cultivated as an oilseed crop and later became a nut crop.
In the U.S., they are mostly grown in California. We can grow almonds competitively because of mechanization. Mediterranean, Australia, S. Africa etc. High in protein.


Almonds

Chestnuts
Today most come from Europe (Castanea sativa, Fagaceae) and Japan and China (C. crenata). The chestnut blight wiped out the American chestnut (Castanea dentata) about 1900-1930. Chestnuts are extremely popular in Europe and in Asia.

Hazel nuts
Hazel nuts (Corylus avellana, Corylaceae) are native to the Old World. This is the common cultivated species. Other Corylusspecies occur in the New World however, e.g., Corylus americana. They are also much more popular in Europe than here. In the U.S., most come from Oregon (about 95%). High in oil.


Hazelnuts

Pistachios
Pistachios (Pistachia vera) come from the poison ivy family -- the Anacardiaceae. These nuts are native to the near east and central Asia. They have been cultivated for over 3000 years.
Turkey, Iran, Afghanistan, India major producers. The "nut" is the seed enclosed by the endocarp. The pulpy part is removed before marketing. The "nuts" are often dyed red. High in protein.

Miscellaneous temperate nuts.
Piñon from Pinusspp. Important in the S.W. U.S. and Mexico. Other species important to Near East.
Ginkgo bilobaseeds are eaten in the orient after fermenting off the outside portion. They are then boiled or roasted. Supposedly poisonous if not.



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Revised February 2005


© David S. Seigler, Integrative Biology 363, Plants and Their Uses, Department of Plant Biology, 265 Morrill Hall, 505 S. Goodwin Ave., University of Illinois, Urbana, Illinois 61801, USA. 217-333-7577. seigler@life.uiuc.edu.