David S. Seigler Department of Plant BiologyUniversity of IllinoisUrbana, Illinois 61801 USAseigler@life.illinois.eduhttp://www.life.illinois.edu/seigler
Perennial temperate fruits - Outline Importance: • fruits and nuts • eaten in all cultures, large amounts Botanical • What is a fruit? Pericarp (endo-, meso-, and exo-) see pg. 18-20, p. 53-57 • What is a nut? Seeds, table p. 62, 70-74
Properties: • Nutritive • Fruits • sugars • vitamins, minerals • oils (olive, avocado) • Nuts • sugars • oils • protein
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 Temperate Nuts • Juglans regia (walnut) • Prunus amygdalus (almond)
Types of fruits • “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.
Parthenocarpic fruit • Fruit and seed development can occur without fertilization. • Fruit that develops without seed formation is "parthenocarpic". • Fruit of this type have been selected because they mature fruits spontaneously without fertilization.
Fruits are often classified by the number of ovaries involved in their formation • By the position of the ovary (superior or inferior) • By whether the fruit is dry or fleshy at maturity • By the way the fruit releases its seeds (dehiscence).
Table 3-1, p. 54 • GO OVER THIS TABLE (pg. 54)
Simple fruits have seeds surrounded by three layers: • Endocarp • Mesocarp • Exocarp • FIG. 3-3, pg. 57.
Simple fruits indehiscent or dehiscent. • Dry fruits and their seeds usually dispersed by wind, water, or gravity. • In grains or caryopses the seed coat is fused to the ovary wall. • In some other fruits, 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. • Fruits of this type often called accessory fruits. • Many are commonly 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, e.g. pineapple.
Composition of fruits • Fleshy fruits evolved to attract animals that eat them and disseminate the seeds. • Fleshy part consists of flavored sugar solutions without many nutrients. • Fruits are good sources of water soluble vitamins. • Avocado and olive are exceptions. • Table 3-3, p. 60.
Composition of seeds • Seeds are quite different in composition from fruits. • Seeds usually have fats, oils and/or starches. • Seeds often protected by hard shells, seed coats, and toxic compounds. • Seeds usually high in nutritional energy. • Table 3-4.
Most fruits consumed raw. • Fruits also preserved by drying, cold storage, as jellies, preserves or sugared, smoked or frozen. • Fruits never basic to the diets of any groups of peoples, but important in many, especially in the Middle East, for example.
Domestication of fruits • Fruits have been used by hunter-gatherers up to the present. • Although plants related to the ancestors of most perennial fruit crops occur in both the Old and New World, the crop plants almost all came from the Old World. • A few New World ones have been domesticated in the last 200-300 years (e.g., the blackberry and the cranberry).
Most perennial fruit crops are slow growing trees or shrubs. • Selection has not changed most of them significantly with the exception of larger fruits, better taste, disease resistance, and lower toxicity. • Most are still hand harvested. • Where they are grown is largely dependent on where labor is cheap.
Apples, Malus spp. • Apples are the most important temperate fruit tree in the world. • Apples, pears, peaches, plums, cherries, strawberries, blackberries, and quince 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. • Pg. 57-64 in the text.
The Complete Book of Fruits & Vegetables, F. Bianchini, F. Corbetta, M. Pistola, Crown Publishers, New York, 1973 Apple cultivars
The genera Malus, Pyrus and Cydonia all 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, probably from the Caucasus Mountains. • Good apple cultivars mostly cultivated by grafting. • We eat the "floral cup" of the apple.
World production of fruits TABLE 3-5 Pg. 62-63. • Large countries almost always lead in production of crop plants, but they may be relatively more important in small countries or regions of a large country. • Fruit crops usually require inexpensive labor to be competitive.
Pears (Pyrus spp.) • Pears probably the second most important tree fruit crop. • The pear may have arisen in sw Asia or in China or both. • No pears native to the New World. • Pears usually propagated by grafting. • Both pears and quinces are more popular in Europe and the Orient than in the U.S.
Pyrus communis, pears The Complete Book of Fruits & Vegetables, F. Bianchini, F. Corbetta, M. Pistola, Crown Publishers, New York, 1973
Fruits from the genus Prunus • Several important fruits belong to the genus Prunus. • These include 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.
Prunus cerasus, cherry cultivars • These plants have been cultivated in the Old World for at least 2000 years. • There are wild species of cherries and plums in the New World as well. The Complete Book of Fruits & Vegetables, F. Bianchini, F. Corbetta, M. Pistola, Crown Publishers, New York, 1973
Prunus angustifolia, Chickasaw plum Prunus armeniaca, apricots
Prunes are dried plums. Drying formerly was the major method of preserving fruit. Otherwise they would only be available in season. • Many grown as ornamentals and not for their fruits. • Peaches are the third most important fruit crop in the U.S. (apples, oranges, peaches). • Peaches 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 virginiana in eastern North America most common. F. chiloensis from Chile. • These two species hybridized in a botanic garden in Europe about 1750 to produce the commonly cultivated strawberry today (F. ananassa).
Strawberries The Complete Book of Fruits & Vegetables, F. Bianchini, F. Corbetta, M. Pistola, Crown Publishers, New York, 1973
Rubus sp., flowers and aggregate fruits Members of the genus Rubus are native to both the Old and New World. Representatives of both are cultivated.
Blueberries and cranberries both belong to the genus Vaccinium (Ericaceae). This group is native to both North America and Europe/Asia. Vaccinium angustifolia, lowbush blueberry
Grapes, Vitis vinifera • 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.
Grapes, Vitis vinifera The Complete Book of Fruits & Vegetables, F. Bianchini, F. Corbetta, M. Pistola, Crown Publishers, New York, 1973
Raisins are dried grapes. Again, formerly drying was one of the major ways of preserving fruits. • “Fossils” of grapes known from Europe. Grapes were cultivated by 5000 B.C. in India and in S.E. Europe. In North America grapes widely eaten by the Indians (but not cultivated). • Disease and insect pest problems will be discussed later. • Grape production in California highly mechanized.
Olives (Olea europaea) • Olives have been an important food and source of oil for more than 5000 years. Olea europaea (Oleaceae) 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.
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 - slow growing and frequently vegetative reproduction. • Used in all cultures, but not major in any today. • Many nut crops grown on arid, agriculturally marginal lands where labor is cheap.
The major nut crops are: walnut (English), almond, and cashew (discussed under Tropical Nut Crops). 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 • Acorns and hickory nuts were major food plants of many American Indian groups of the eastern U.S. and also of California.