Whether cultivated or wild, all cotton belongs to the genus Gossypium, related to hibiscus, in the family Malvaceae. Cotton grows naturally in relatively arid areas in tropical and subtropical regions of the Middle East, Africa, the Americas, Australia, and some South Pacific islands. Researchers have identified 31 species of cotton, 4 of which are domesticated, bearing seed fibers capable of being spun. Two of these cultivated species are indigenous to the middle East, two are indigenous to the Americas. All cotton grown in the U.S. is from the new world group, characterized by 26 pairs of chromosomes. Cotton quality is measured by "grade," which is based on the color and purity of the lint; and by "staple," or the length of the fibers. The fruit of the cotton plant is called a boll (pronounced bowl) which splits open to reveal the fiber-covered seed. The price received by cotton producers is determined by both the quantity and quality of the harvested lint.

image courtesy USDA-ARS

Use of cotton predates recorded history by several centuries. Cotton fabrics dating back to 3000 BC were found in the Indus river valley, and cotton specimens dating to 2500 BC have been found in Peru. These and other ancient remains show that the cultivation and manufacture of cotton evolved independently in both the old and the new world. Spinning and weaving of cotton in the old world began in India. Trade routes developed by Alexander the Great introduced the textiles of India to the rest of the Middle East and Europe and eventually the increased demand for Indian goods led to European explorations to find a sea route to India, including the 1492 expedition of Christopher Columbus, where he landed in America.

In 1793 Eli Whitney invented the cotton gin, a machine that made it easy to remove the cotton fibers, or "lint", from the cotton seed. The southern states turned their agricultural systems almost exclusively to the production of cotton, increasing output from 4,000 bales a year to 4,500,000 bales, the year before the Civil War. Although production decreased during the war, it quickly rose again to a peak of 16,000,000 bales prior to World War I. After 1919, production shifted west, and Texas, New Mexico, Arizona and California became major cotton states.

image courtesy USDA-ARS

In its native habitat, cotton is a perennial that does not die in the fall. Instead, the plant becomes dormant during periods of drought and resumes growth with the return of favorable rainfall. Another growth characteristic of cotton is its indeterminate fruiting habit. Rather than flowering during a distinct period following vegetative growth, cotton simultaneously produces vegetation and fruiting structures. A cotton fruit begins as a small flower bud or "square" which flowers about 21 days after it reaches the size of a pinhead (just visible to the naked eye). A new bloom is white the first day (which is when pollination occurs) and turns red by the second day. Thirty to 35 days after emergence of the seedling, the first square will be formed on a fruiting branch arising from the axil (node) of the fifth to seventh true leaf. The plant will continue to produce additional fruiting branches in an orderly manner up the main stem. Each fruiting branch may produce several squares, but most of the harvestable bolls will be found at either the first or second position on a fruiting branch.

Links to other sites with information about cotton:

• Cotton Incorporated
• Cotton Links on the Internet
• ARS Cotton Physiology & Genetics
• NMSU Cotton Lab
• Cotton Database

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Last Updated: June 5, 1998