The closely related genus Broussonetia is also commonly known as mulberry, notably the Paper Mulberry, Broussonetia papyrifera.
Mulberries are swift-growing when young, but soon become slow-growing and rarely exceed 10–15 m (33–49 ft) tall. The leaves are alternately arranged, simple, often lobed, more often lobed on juvenile shoots than on mature trees, and serrated on the margin.
The fruit is a multiple fruit, 2–3 cm (0.79–1.2 in) long. The fruits when immature are white or green to pale yellow with pink edges. In most species the fruits are red when they are ripening, turning dark purple to black and have a sweet flavor. The fruits of the white-fruited cultivar of the white mulberry are green when young and white when ripe; the fruit in this cultivar is also sweet but has a very mild flavor compared with the darker variety.
SpeciesThe taxonomy of Morus is complex and disputed. Over 150 species names have been published, and although differing sources may cite different selections of accepted names, only 10–16 are generally cited as being accepted by the vast majority of botanical authorities. Morus classification is even further complicated by widespread hybridisation, wherein the hybrids are fertile.
The following species are generally accepted:
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Uses and cultivationThe ripe fruit is edible and is widely used in pies, tarts, wines, cordials and tea. The fruit of the black mulberry, native to southwest Asia, and the red mulberry, native to eastern North America, have the strongest flavor. The fruit of the white mulberry, an east Asian species which is extensively naturalized in urban regions of eastern North America, has a different flavor, sometimes characterized as insipid. The mature plant contains significant amounts of resveratrol, particularly in stem bark. The fruit and leaves are sold in various forms as nutritional supplements. Unripe fruit and green parts of the plant have a white sap that is intoxicating and mildly hallucinogenic.
Black, red, and white mulberry are widespread in Northern India, Azerbaijan, Jordan, Syria, Lebanon, Georgia, Armenia, Pakistan, Iran, Turkey, and Afghanistan, where the tree and the fruit are known by the Persian-derived names toot (mulberry) or shahtoot (King's or "superior" mulberry). Jams and sherbets are often made from the fruit in this region. Black mulberry was imported to Britain in the 17th century in the hope that it would be useful in the cultivation of silkworms. It was much used in folk medicine, especially in the treatment of ringworm. Mulberries are also widespread in Greece, particularly in the Peloponnese, which in the Middle Ages was known as Morea (Greek: Μωριάς, Morias), deriving from the Greek word for the tree (Greek: Μουριά, Μouria). Mulberry trees were used for silk production, which was a major source of wealth for the region.
Mulberry leaves, particularly those of the white mulberry, are ecologically important as the sole food source of the silkworm (Bombyx mori, named after the mulberry genus Morus), the pupa/cocoon of which is used to make silk. Other Lepidoptera larvae also sometimes feed on the plant including common emerald, lime hawk-moth, and the sycamore.
Mulberries can be grown from seed, and this is often advised as seedling-grown trees are generally of better shape and health. But they are most often planted from large cuttings which root readily. The mulberry plants which are allowed to grow tall with a crown height of 5 - 6 feet from the ground level having stem girth of 4 -5 inches or more is called tree mulberry. They are specially raised with the help of well grown saplings of 8 - 10 months old with any of the varieties recommended for rain fed areas like S-13 (for red loamy soil) or S-34 (black cotton soil) which are tolerant to draught or soil moisture stress conditions. Usually the plantation is raised as block plantation with a spacing of 6 feet x 6 feet or 8 feet x 8 feet as plant to plant and row to row distance. The plants are usually pruned once in a year during monsoon (July - August) at a height of 5 - 6 feet from the ground level and allowed to grow with maximum of 8 - 10 shoots at crown. The leaf is harvested 3-4 times in a year by leaf picking method under rain fed or semi-arid conditions depending upon the monsoon. The tree branches pruned during the fall season (after the leaves have fallen) are cut and used to make very durable baskets which are used in a lot of village jobs related to agriculture and animal husbandry.
Anthocyanins from mulberry fruitsAnthocyanins are pigments which hold potential use as dietary modulators of mechanisms for various diseases and as natural food colorants. Due to increasing demand for natural food colorants, their significance in the food industry is increasing. Anthocyanins are responsible for the attractive colors of fresh plant foods, producing colors such as orange, red, purple, black, and blue. They are water-soluble and easily extractable.
A cheap and industrially feasible method to purify anthocyanins from mulberry fruit which could be used as a fabric tanning agent or food colorant of high color value (of above 100) has been established. Scientists found that out of 31 Chinese mulberry cultivars tested, the total anthocyanin yield varied from 148 mg to 2725 mg per liter of fruit juice. Total sugars, total acids, and vitamins remained intact in the residual juice after removal of anthocyanins and that the residual juice could be fermented to produce products such as juice, wine, and sauce.
Worldwide, mulberry is grown for its fruit. In traditional and folk medicine, the fruit is believed to have medicinal properties and is used for making jam, wine, and other food products. As the genus Morus has been domesticated over thousands of years and constantly been subjected to heterosis breeding (mainly for improving leaf yield), it is possible to hybridize breeds suitable for berry production, thus offering possible industrial use of mulberry as a source of anthocyanins for functional foods or food colorants which could enhance the overall profitability of sericulture.
Anthocyanin content depends on climate, area of cultivation, and is particularly higher in sunny climates. This finding holds promise for tropical sericulture countries to profit from industrial anthocyanin production from mulberry through anthocyanin recovery.
This offers a challenging task to the mulberry germplasm resources for
- exploration and collection of fruit yielding mulberry species;
- their characterization, cataloging, and evaluation for anthocyanin content by using traditional as well as modern means and biotechnology tools;
- developing an information system about these cultivars or varieties;
- training and global coordination of genetic stocks;
- evolving suitable breeding strategies to improve the anthocyanin content in potential breeds by collaboration with various research stations in the field of sericulture, plant genetics, and breeding, biotechnology and pharmacology.