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Agriculture and Biodiversity


Preserving Wild Relatives of Crops

Conserving biodiversity is not merely an aesthetic or ethical goal. Saving endangered plants and animals because they are beautiful or have intrinsic value is a worthy objective, but maintaining a bio-diverse world also has tremendous value to people.

A good example of biodiversity's economic value is the role traditional crop varieties and wild relatives of agricultural crops play in agricultural innovation. Plant breeders are continuously drawing on traits from wild or obscure relatives of crops like wheat, tomatoes, rice, corn and potatoes to breed crops resistant to diseases or with improved nutritional and other beneficial qualities.

Canola is an important Canadian example of the benefits of maintaining biodiversity. Using germplasm acquired in other countries, Canadian scientists turned conventional oilseed rape, which had anti-nutritional properties, into a nutritious vegetable oil, and a billion-dollar industry.

There are two ways that genetic material from wild and traditional varieties can be preserved. One is in gene banks that save seeds and other regenerative material from a wide range of plants. Agriculture Canada at the University of Saskatchewan in Saskatoon hosts the central facility of Canada's major gene bank, Plant Gene Resources Canada.

The other way is to preserve wild and traditional relatives of crops in situ, meaning in the fields and forests where they grow. This method can be more economical than using gene banks, since expensive facilities are not required.

In June 2004, a major project to promote in situ conservation was launched by the International Plant Genetic Resources Institute (IPGRI) in collaboration with the United Nations Environment Programme (UNEP) and national and international partners. The IPGRI now works under the name Bioversity International.

The project responds to increasing concern over the loss of genetic resources. For example, more than one in 20 of the species of Poaceae, the botanical family that includes cereal crops such as wheat, maize, barley and millet, are threatened with extinction from deforestation, habitat loss and intensive agriculture.

The new scheme will pool existing information from a wide variety of sources on wild relatives of crops in each of several key countries. An information exchange network will be set up allowing scientists and breeders to pinpoint promising traits for improving crop production.

Wild relatives make a major contribution to improving Saskatchewan's main crop.

Wheat is the staple food for approximately one in three people worldwide. But diets based largely on cereals lack important nutrients such as iron, zinc and vitamin A.

A wild relative of wheat from the Eastern Mediterranean was used to increase the protein content of bread and durum wheat. The International Centre for the Improvement of Wheat and Maize (CIMMYT) has shown that other wild relatives of wheat have up to 1.8 times more zinc and 1.5 times more iron in their grains than ordinary wheat and could be used to improve levels of these minerals in wheat varieties.

Rice is the world's other major grain crop. In the 1970s, an outbreak of grassy stunt virus devastated the rice fields of millions of farmers in South and South-East Asia. The virus, transmitted by the brown plant hopper, prevents the rice plant from producing flowers and grain. Scientists from the International Rice Research Institute (IRRI) screened more than 17,000 cultivated and wild rice samples for resistance to the disease.

A relative of rice, Oryza nivara, growing in the wild in Uttar Pradesh was found to have one single gene for resistance to the grassy stunt virus. This gene is now routinely incorporated in all new varieties of rice grown across more than 100,000 square km of Asian rice fields.

Similar research is underway on crops from tomatoes to peanuts to broccoli.

These examples underline the importance of programs to conserve biodiversity. When we conserve wild forests and grasslands, we are not only conserving beautiful ecosystems, we are sustaining our way of life. In situ conservation program may also be the most cost-effective way of doing this.