Tree Fruits from Semi Tropical Regions Citrus fruits Orange trees produce more than any other perennial fruit tree crop in the U.S. All of these fruits are in the genus Citrus (Rutaceae). All citrus species grow on trees with shiny, evergreen leaves with expanded flattened petioles. REVIEW A hesperidium is another specialized berry and includes the citrus fruits. The thick peel that has numerous oil cavities is the exocarp and mesocarp. The genus Citrus arose from Southeast Asia, but cultivated citrus fruits are derived from species native to India, China and Myanmar (Burma). Despite the abundance of named citrus species, morphological and molecular studies have determined four common fruits:

Tree Fruits from Semi Tropical Regions Citrus x sinensis (mandarin x pummelo) is one of four most widely grown fleshy fruits in the world. Oranges were considered “golden apples” in Greek mythology. The goddess of fertility gave the seeds to Hera when she married Zeus. Oranges were transported along caravan routes from Asia to the Persian Empire. The Moors brought oranges to Spain for religion and medicine. The Spanish and the Portuguese introduced sweet oranges to the New World in the 1500’s. The English word for the color orange is derived from the Arabic name of the fruit. Oranges were first grown in Florida in 1565, sweet oranges did not become an important U.S. commodity until 1820. The three main classes of hybrid sweet oranges:

Tree Fruits from Semi Tropical Regions The most commonly grown normal type is the Valencia orange. Valencia cultivars were introduced from the Azores in Florida (1870) and California (1876). Valencia oranges are the most important variety grown in Florida. Navel oranges are the leading orange variety grown in California. The mutation in the Washington navel, the modern commercial variety, originated in Bahia, Brazil before the 1820’s. Navel oranges are formed because the flowers produce an abnormally small ovary on top of a regular ovary. When the fruit matures, the second ovary becomes the “navel.” The second ovary is sterile and the ovules do not produce seeds. New plants must be vegetatively propogated. The sweet orange was not the first citrus grown in the Americas. Columbus brought seeds to the New World in 1493 and established them on the island of Hispanola.

Tree Fruits from Semi Tropical Regions Bitter oranges are used for making preserves, marmalade and orange liqueurs. The fragrance is extracted as neroli oil and used in perfume making. Citrons are native to Southeast Asia, but they were grown in Mesopotamia in 4000 B.C. The peel of citron is candied and used in fruitcakes. Buddha's hand, Citrus medica var. sarcodactylis, or the fingered citron Tree Fruits from Semi Tropical Regions Of all citrus fruits, lemons are exploited for secondary compounds. Oils in lemon rinds are used for:

Tree Fruits from Semi Tropical Regions Avocados, or alligator pears, Persea americana, (Lauraceae) have the highest energy containing fruit pulp, (2000 to 2800 calories per kg). Although avocados are known only as cultivated species, they appear in some of the oldest archeological deposits in southern Mexico (10,000 ybp). Avocados were most likely independently domesticated 3 times in the Americas: Avocados were first planted as a commercial venture in the U.S. in Florida in 1893. This meaning refers to either: Tree Fruits from Semi Tropical Regions The fruits of the date palm, Phoenix dactylifera (Arecaceae).

Mexican

Tree Fruits from Semi Tropical Regions Fruits of wild relatives of the modern commercial date were gathered for thousands of years by nomadic tribes wandering acrossarid regions from India to the western Mediterranean. Dates were domesticated about 4500 B.C. Muslims believe that the date palm was made from the dust left after God made Adam. Dates were very important to desert travelers because: Date palms are dioecious. As early as 2300 B.C., agriculturalists learned to hang a male inflorescence in a female tree to ensure fruit production. Ficus carica is a native of the Mediterranean region. Figs are also mentioned in Egyptian documents (2750 B.C.). To the Greeks, an edible fig was a sykon. The term sykon led to the name of the fig fruit, syconium. REVIEW Multiple fruits are the enlarged ovaries of multiple flowers that more or less fuse together.

Pineapple inflorescence

Multiple fruit

Flower

Each

segment

develops

from the

carpel

of one

flower

Pineapple fruit

Tree Fruits from Semi Tropical Regions Common figs such as Kadota and Mission can produce fruits without pollination. Wild figs and most of the edible varieties have a very elaborate pollination system that involves tiny wasps.

Kadota Mission