Wheat

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Wheat (Triticum spp. L.) is grown on more hectares than any other food crop, and is one of the most important sources of calories second only to rice and first as a source of protein for humans in many parts of the world.

Zero tillage wheat growing in the field in Fatehgarh Sahib district, Punjab, India (Photo: CIMMYT)
Zero tillage wheat growing in the field in Fatehgarh Sahib district, Punjab, India (Photo: CIMMYT)

Origin and use

Wheat was domesticated in the Near East at least 9,000 years ago and for 8,000 years has been the basic staple food of the major civilizations of Europe, West Asia, and North Africa. Although the crop is most successful in temperate zones, it can be grown beyond these limits. Research by the International Maize and Wheat Improvement Center (CIMMYT) has shown that wheat production in much warmer areas is technologically feasible.

While many farmers grow their wheat on relatively large farms, many others, for example in South Asia, Ethiopia, and Eritrea, are resource poor, with little land. The demand for quality wheat products in developing countries is increasing with increasing populations and urbanization but farming systems impose major constraints on the environment and the future capacity to produce.

Production

The leading producers of wheat in the developing world in 2010 are China (115 million metric tons annually), India (81), Pakistan (23) and Turkey (20). Annual world wheat production has increased by more than 50% over the past 30 years from 435.7 to 673.7 million metric tons, while the area planted to wheat has decreased slightly from 231.8 to 221.6 million hectares, indicating a substantial increase in yield of over 60%.

Many countries do not grow enough wheat to meet demand and they have to import large quantities. In 2009, the leading importers of wheat in the developing world were Algeria (5.7 million metric tons), Iran (5.5), Brazil (5.4), Indonesia (4.7), Egypt (4.1) and Bangladesh (4.1).

Nutrition

Wheat kernel contains an average of 70% carbohydrate, 12% protein, 2% fat, 1.8% minerals, and 2.2% crude fiber. Thiamine, riboflavin, niacin, and small amounts of vitamin A are also present. Half a kilogram of wheat contains about 1,500 calories. In Central and West Asia and North Africa, it contributes more calories to diets than all other cereals combined.

Impact of CGIAR Centers

More stable wheat yields generate benefits with an estimated annual value of US$143 million. Research to maintain resistance to a single major disease of wheat – leaf rust – generated benefits from 1973 to 2007 that are currently worth US$5.4 billion. The global economic value of genetic resistance to various wheat diseases amounts to US$2 billion annually.

Between 1988 and 2002, nearly 1,700 new wheat varieties, of which about 75% have some CIMMYT ancestry, were released in the developing world. The additional annual production attributable to CIMMYT wheat breeding research is valued at US$0.5 to $3.9 billion, depending on the assumptions used.

Conservation cropping – which combines minimal soil disturbance, early planting, stubble retention, and crop rotations – reduces production costs, improves soil structure and water retention, and reduces soil erosion. In northern Syria, zero-tillage with early planting gave significantly higher yields than conventional tillage and late planting. For example, in 2009/10, net returns to wheat cropping increased by US$250 per hectare. Similarly, a conservative estimate of the zero-tillage program in the rice–wheat systems in India shows that it yielded a net present value of US$94 million, equivalent to a benefit–cost ratio of 39 and an internal rate of return of 57%. And in both cases, this is before taking into account the long-term environmental benefits.

A virulent race of wheat stem rust, Ug99, emerged in Uganda in 1998 and 1999, presenting a severe threat to the world’s wheat crops. The recent report of the spread of Ug99 into South Africa has raised further concerns. Integrated research efforts by CIMMYT, International Center for Agricultural Research in the Dry Areas (ICARDA) and the Food and Agricultural Organization of the United Nations (FAO) with national research organizations to breed and distribute resistant varieties of wheat are keeping the disease in check.

More recently, another fungal disease, stripe rust (or yellow rust) has become a serious problem across Africa, the Middle East and Asia, with epidemics in 2009 and 2010. CIMMYT already has a number of wheat lines with resistance to stripe rust. Many of these are also resistant to Ug99 and have 10–15% higher yields than currently-grown varieties.

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