Research Focuses on Yield and Improved Resistance
February 10, 2011 Cotton is an immensely important crop for the sustainable economy of India. The crop is cultivated by about 6 million farmers and supports the livelihood of 40 million to 50 million people in India, counting those who are engaged in post-harvest processing and trade.
The textile industry in India utilizes about 65 percent of the total raw cotton fiber produced in the country and contributes to 14 percent of industrial production, 4 percent of the gross domestic product (GDP), and provides direct employment to more than 33 million people.
Archeological evidence from the Harappa civilization (2,300 B.C. to 1,750 B.C.) clearly shows that Indian civilization had developed highly sophisticated textile craftsmanship more than 4,000 years ago. The world-famous Indian Dhaka muslins were woven from the Indian Desi tree species Gossypium arboreum, with mean fiber length of 18 mm to 24 mm, but the yarn was one of the finest ever heard of: 345 to 356 counts.
For centuries, the Indian Dhaka handloom muslins ruled the world textile trade. The British East India Company, which was established in 1615 in India, started exporting “Calicoes” and Dhaka muslins to Britain.
In 1721, the British Parliament passed an act prohibiting Calicoes and the import of cotton textiles from India in order to protect the wool industry in Britain from total collapse.
Textile industrialization started in the 18th century, but the spinning frames invented for high-speed spinning were ideally suited for American cotton, Gossypium hirsutum, which has a medium staple length and good strength. Soon, Britain established itself as the world’s leading manufacturer and exporter of cotton fabrics and garments, using imported raw cotton from the United States.
India steps onto the world cotton stage
The American Revolutionary War, however, caused a shortage of raw American cotton exports to England from 1775 to 1783. Since India was the second-largest cotton producer in the world after the United States, the British immediately considered India as an alternative option for their textile mills. They introduced the American cotton variety, Borbon G. hirsutum, punctatum, from Malta and Mauritius into Bombay and Madras Provinces of India in 1790, and from that point on, efforts were intensified to improve and promote the cultivation of American cotton in India.
By the time India gained its independence in 1947, a total of 2.3 million bales–comprised of 67 percent medium staple and 33 percent short staple cotton, from 97 percent Desi varieties (65 percent G. arboretum, 32 percent G. herbaceum)–were produced from 4.3 million hectares, while the remaining 3 percent of medium and long staple cotton was produced from G. hirsutum and G. barbadense.
In the 60 years since independence, about 175 high-yielding varieties and 50 intra- and interspecific hybrids, with superior fiber traits suitable for different agro-ecological regions of the country, were developed by researchers in India. From the meager 2.3 million bales harvested in 1947, production increased to 17.6 million bales in 1996/97 and rose to an all-time-highest record of 31.5 million bales in 2007/08.
Currently, about 90 percent of the cotton area in India is producing the American cotton species, G. hirsutum. About 70 percent of the 30 million bales produced in India consist of long-staple, superior-quality fiber, most of which is also exported. Technologies that were introduced in India from 2000 through 2002–including Bt-cotton (Bacillus thuringiensis, Bt-based, genetically modified (GM) cotton), IRM (insecticide-resistance management), IPM (integrated pest management), and the introduction of new cotton hybrids and several new, effective insecticides–are believed to have contributed to the significant increase in production seen in recent years.
The American cotton variety, G. hirsutum, and Sea Island cotton variety, G. barbadense, are more susceptible to insect pests such as jassids, whiteflies, and American bollworm (Helicoverpa armigera), as well as diseases such as bacterial blight, Verticillium wilt, parawilt, and leaf curl virus, thereby warranting intensive use of pesticides for protection. The American cotton hybrids are also input-responsive and highly susceptible to biotic and abiotic stresses.
By virtue of having been cultivated for ages, the two Desi species, G. arboreum and G. herbaceum, are known to cope with biotic and abiotic stresses with ease under their native conditions. As a result, those varieties were preferred by farmers for several years over the other introduced cotton species.
Bt to battle bollworms
By the year 2000, bollworms were reported to have developed resistance to almost all recommended insecticides and were causing huge economic losses despite repeated pesticide applications. The introduction of Bt cotton in 2002 came as a big relief. The acreage under Bt cotton increased from 29,000 hectares in 2002 to an estimated 90 percent of the total cotton area (11 million hectares) in 2010.
The introduction of Bt cotton appears to have resulted in a reduction of market share of insecticides used on cotton, from 43 percent in 2003 to a mere 25 percent in 2008. Currently, the estimated number of Bt hybrids available for cultivation in India has increased to more than a thousand different growths.
A number of yield-reducing constraints and challenges have emerged in India over the last decade. The most significant challenges include:
• erratic rainfall,
• supraoptimal temperatures,
• the re-emergence of the cotton leaf curl virus in the north,
• the emergence of new insect pests such as mealybugs and miridbugs,
• the resurgence of sucking pests,
• reddening of leaves,
• jassid resistance to insecticides,
• emerging bollworm resistance to Bt cotton, and
• parawilt.
The Central Institute for Cotton Research has been focusing on the development of sustainable technologies for India’s cotton crop, especially in the 60-percent-rain-fed region of the country.
Research efforts are under way to discover new genes that boast superior fiber quality traits and other economic traits, including RNA interference for resistance to biotic and abiotic stress.
The Institute has been developing GM varieties of Desi and American cotton species that are suitable for high-density planting; developed for specific agri-eco zones in the country; have the highest harvest index (less vegetation versus more bolls) under conditions of low inputs; and labor requirements.
Our researchers have developed several technologies that are widely used all ocross the country, including:
• molecular diagnostic tools for disease detection,
• immunological and molecular kits for GM detection,
• insect resistance management and pest management strategies, and
• nutrient- and water-management technologies.
The sustained efforts of India’s publicly funded institutions and the private research and development organizations are expected to result in the development of new, high-yielding varieties and hybrids that are resistant to biotic and abiotic stress, require fewer inputs, produce superior-quality fiber, and are suitable for the needs of textile industry, for non-woven material applications, and provide sufficient excess production to support exporters.
In the end, India and the Central Institute for Cotton Research are working hard to meet a production target of 45 million bales of cotton by 2015 and emerge as a global leader in cotton.
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