Tuesday, May 30, 2017

Cotton (Gossypium sp.) is one of the most important and earliest domesticated non-food crops in the world. Used primarily for its fiber, cotton was domesticated independently in both the Old and New Worlds. The word "cotton" originated from the Arabic term al qutn, which became in Spanish algodón and cotton in English.
Nearly all the cotton produced in the world today is the New World species Gossypium hirsutum, but before the 19th century, several species were grown on different continents.
The four domesticated Gossypium species of the Malvaceae family are G. arboreum L., domesticated in the Indus Valley of Pakistan and India; G. herbaceum L. from Arabia and Syria; G. hirsutum from Mesoamerica; and G. barbadense from South America.
All four domestic species and their wild relatives are shrubs or small trees which are traditionally grown as summer crops; domesticated versions are highly drought- and salt-tolerant crops that grow well in marginal, arid environments. Old World cottons have short, coarse, weak fibers that are today primarily used for stuffing and quilt making; New World cottons have higher production demands but provide longer and stronger fibers and higher yields.


Wild cotton is photo-period sensitive--in other words, the plant begins to germinate when the day length reaches a certain point. Wild cotton plants are perennial and their form is sprawling.
Domestic versions are short, compact annual shrubs which do not respond to changes in day length--that's an advantage if the plant grows in places with cool winters because both wild and domestic cottons are frost-intolerant.
Cotton fruits are capsules or bolls which contain several seeds covered by two kinds of fiber: short ones called fuzz and long ones called lint.
Only the lint fibers are useful for making textiles; and the domestic plants have larger seeds covered with comparatively abundant lint. Cotton is traditionally harvested by hand, and then the cotton is ginned--processed to separate the seeds from the fiber.
After the ginning process, the cotton fibers are batted with a wooden bow to make them more flexible, and carded with a hand comb to separate the fibers before spinning. Spinning twists the individual fibers into a yarn, which can be completed by hand with a spindle and spindle whorl or with a spinning wheel.


Cotton was first domesticated in the Old World about 7,000 years ago; the earliest archaeological evidence for cotton use is from the Neolithic occupation of Mehrgarh, in the Kachi Plain of Balochistan, Pakistan, in the sixth millennium BC. Cultivation of G. arboreumbegan in the Indus Valley of India and Pakistan, and then eventually spread over Africa and Asia, whereas G. herbaceum was first cultivated in Arabia and Syria.
The two main species, G. arboreum and G. herbaceum, are genetically very different and probably diverged well before domestication. Specialists agree that the wild progenitor of G. herbaceum was an African species, whereas the ancestor of G. arboreum is still unknown.
Regions of possible origin of the G. arboreum wild progenitor are likely Madagascar or the Indus Valley, where the most ancient evidence for cultivated cotton has been found.
Gossypium arboreum
Abundant archaeological evidence exists for the initial domestication and use of G. arboreum, by the Harappan (aka Indus Valley) civilization in Pakistan. Mehrgarh, the earliest agricultural village in the Indus Valley, has multiple lines of evidence of cotton seeds and fibers beginning about 6000 BP. At Mohenjo-Daro, fragments of cloth and cotton textiles have been dated to the fourth millennium BC, and archaeologists agree that most of the trade that made the city grow was based on cotton exportation.
Raw material and finished cloth were exported from south Asia into Dhuweila in eastern Jordan by 6450-5000 years ago, and to Maikop (Majkop or Maykop) in the northern Caucasus by 6000 BP.
Cotton fabric has been found at Nimrud in Iraq (8th-7th centuries BC), Arjan in Iran (late 7th-early 6th centuries BC) and Kerameikos in Greece (5th century BC). According to Assyrian records of Sennacherib (705-681 BC), cotton was grown in the royal botanical gardens at Nineveh, but cool winters there would have made large-scale production impossible.
Because G. arboreum is a tropical and subtropical plant, cotton agriculture did not spread outside the Indian subcontinent until thousands of years after its domestication. Cotton cultivation is first seen in the Persian Gulf at Qal'at al-Bahrain (ca 600-400 BC), and in North Africa at Qasr Ibrim, Kellis and al-Zerqa between the 1st and 4th centuries AD. Recent investigations at Karatepe in Uzbekistan have found cotton production dated between ca. 300-500 AD. Cotton may have been grown in the Xinjiang (China) province cities of Turfan and Khotan by the 8th century AD. Cotton was finally adapted to grow in more temperate climates by the Islamic Agricultural Revolution, and between 900-1000 AD, a boom in cotton production spread into Persia, Southwest Asia, North Africa and the Mediterranean Basin.
Gossypium herbaceum
G. herbaceum is much less well-known than G. arboreum. Traditionally it is known to grow in African open forests and grasslands. Characteristics of its wild species are a taller plant, compared to the domesticated shrubs, smaller fruit and thicker seed coats. Unfortunately, no clear domesticated remains of G. herbaceum have been recovered from archaeological contexts. However, the distribution of its closest wild progenitor suggests a northward distribution toward North Africa, and the Near East.


Among the American species, G. hirsutum was apparently cultivated first in Mexico, and G. barbadense later in Peru. However, a minority of researchers believe, alternatively, that the earliest type of cotton was introduced into Mesoamerica as an already domesticated form of G. barbadense from coastal Ecuador and Peru.
Whichever story ends up to be correct, cotton was one of the first non-food plants domesticated by the prehistoric inhabitants of the Americas.
In the Central Andes, especially in the north and central coasts of Peru, cotton was part of a fishing economy and a marine-based life style. People used cotton to make fishing nets and other textiles. Cotton remains have been recovered in many sites on the coast especially in residential middens.
Gossypium hirsutum (Upland cotton)
The oldest evidence of Gossypium hirsutum in Mesoamerica comes from the Tehuacan valley and has been dated between 3400 and 2300 BC. In different caves of the region, archaeologists affiliated to the project of Richard MacNeish found remains of fully domesticated examples of this cotton.
Recent studies have compared bolls and cotton seeds retrieved from excavations in Guila Naquitz Cave, Oaxaca, with living examples of wild and cultivated G. hirsutum punctatumgrowing along the east coast of Mexico. Additional genetic studies (Coppens d'Eeckenbrugge and Lacape 2014) support the earlier results, indicating that G.
hirsutum was likely originally domesticated in the Yucatán Peninsula .
In different eras and among different Mesoamerican cultures, cotton was a highly demanded good and a precious exchange item. Maya and Aztec merchants traded cotton for other luxury items, and nobles adorned themselves with woven and dyed mantles of the precious material.
Aztec kings often offered cotton products to noble visitors as gifts and to army leaders as payment.
Gossypium barbadense (Pima cotton)
The first clear evidence of domesticated Pima cotton comes from the Ancón-Chillón area of the central coast of Peru. The sites of this area show the domestication process began during the Preceramic period, beginning about 2500 BC. By 1000 BC the size and shape of Peruvian cotton bolls were indistinguishable from today's modern cultivars of G. barbadense.
Cotton production began on the coasts, but eventually moved inland, facilitated by the construction of canal irrigation. By the Initial Period, sites such as Huaca Prieta contained domestic cotton 1,500 to 1,000 years before pottery and maize cultivation. Unlike in the old world, cotton in Peru was initially part of subsistence practices, used for fishing and hunting nets, as well as textiles, clothing and storage bags.


This glossary entry is a part of the guide to the Domestication of Plants, and the Dictionary of Archaeology.
Vegetation History and Archaeobotany 20(5):405-417.
Brite EB, and Marston JM. 2013. Environmental change, agricultural innovation, and the spread of cotton agriculture in the Old World. Journal of Anthropological Archaeology32(1):39-53.
Moulherat C, Tengberg M, Haquet J-F, and Mille Bt. 2002. First Evidence of Cotton at Neolithic Mehrgarh, Pakistan: Analysis of Mineralized Fibres from a Copper Bead. Journal of Archaeological Science 29(12):1393-1401.
Vegetation History and Archaeobotany 20(3):223-239.
Peters AH. 2012. Identity, innovation and textile exchange practices at the Paracas Necropolis, 2000 BPTextiles and Politics: Textile Society of America 13th Biennial Symposium Proceedings. Washington DC: Textile Society of America.
Wendel JF, and Grover CE. 2015. Taxonomy and Evolution of the Cotton Genus, GossypiumCotton. Madison, WI: American Society of Agronomy, Inc., Crop Science Society of America, Inc., and Soil Science Society of America, Inc. p 25-44.
Updated by K. Kris Hirst

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