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美国农业部研究实验室中展示的一捆小麦

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A U.S. Department of Agriculture researcher examines wheat seeds.

Washington — U.S. agricultural scientists and international collaborators have completed sequencing the wheat genome, an accomplishment expected to lead to higher yields and hasten the development of wheat lines with enhanced nutrition and resistance to pests and diseases.

“This opens up the storehouse. We now know what tools we have at our disposal,” said Sandy Miller Hays, spokeswoman for the U.S. Agriculture Department's Agricultural Research Service.

She said that if researchers can find the right tool, or gene, that is the secret to making some wheat resistant to the virulent fungal disease called Ug99, they can do traditional cross-breeding between plants that have a strong version of that gene and plants that have other desired traits. “We’ll wind up with an offspring that gives us everything we want and also have strong resistance,” she said.

Ug99 poses the world’s biggest ever threat to wheat, Hays said. The fungus, or stem rust, was discovered in Uganda in 1999 and has spread to other parts of eastern Africa and to the Middle East. While other rusts only partially affect wheat yields, Ug99 can wipe out entire fields, Hays said. The rust also affects barley and rye.

Agricultural Research Service (ARS) scientists so far have developed 30 wheat lines, each with four or five genes resistant to Ug99 that have been incorporated in various combinations. Multiple genes for resistance will slow the fungi’s ability to overcome a new wheat variety that breeders may develop, Hays said.

“It would be like putting a lock on your door,” she said. “If you only have one lock and a burglar comes along, it might take only a minute or two to get past the lock and into your house. But we’ve put five locks on the [wheat] door and it’s going to take the [rust] burglar more time to get past the locks,” Hays said.

“The amount of time these genes can remain effective is key to maintaining resistance to stem rust,” she added.

 

The ARS-developed lines are among 100 lines of wheat with some stem rust resistance that a nursery in Ankara, Turkey, makes available to wheat breeders in other countries. ARS established the nursery with the International Maize and Wheat Improvement Center, Hays said.

ARS places its wheat research data in the public domain so that scientists around the world can use it to develop better strains of the crop, she said.

“The point is for as many people as possible in as many locations to be able to work on this … and figure out another part of the puzzle” so that if the wheat rust shows up in a field, the wheat will not die, Hays said.

“It is something we work on continuously to try to keep ahead of the fungus,” she said, adding that fungi are always evolving.

U.S. agricultural research goes back to when the U.S. Department of Agriculture was established by President Abraham Lincoln in 1862. ARS was formed in 1953 with the joining of several USDA research units.

In addition to the nursery in Ankara, ARS scientists collaborate in the fight against wheat rust with the International Maize and Wheat Improvement Center in Mexico, the International Center for Agricultural Research in the Dry Areas in Syria, the University of Minnesota, Cornell University and others.

Through the Feed the Future program, USDA and the U.S. Agency for International Development coordinate their research with international donors, multilateral institutions and governmental and nongovernmental bodies to improve agricultural production, reduce food insecurity and generate economic growth.