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Borlaug Institute: China Wheat Vulnerability to Rust Diseases Could Impact Global Food Security

Date Posted: August 31, 2012

Beijing—"Global food security can rise and fall with the success or failure of China’s wheat crop,” said Ronnie Coffman, vice-chair of the Borlaug Global Rust Initiative (BGRI), speaking before the Borlaug Global Rust Initiative’s (BGRI) 2012 Technical Workshop in Beijing, September 1-4.

Because China is the largest wheat producer and consumer in the world, threats to its wheat crop or any significant decline in production could impact food security, according to Coffman, who is also director of international programs and professor of plant breeding at Cornell University.

Wheat is the third leading grain crop in China after rice and maize, with 24 million ha under cultivation, and an average yield of 4.7 tons/ha.

Yearly production stands at 115 million tons, which is 17% of the world’s production.

Zhonghu He, wheat breeder with the International Maize and Wheat Improvement Center (CIMMYT), and member of the Chinese Academy of Agricultural Science, who is based in China, said, “Some of the biggest challenges facing wheat farmers in China are water scarcity, increased occurrence of various diseases, and high temperatures and droughts caused by global climate change, combined with increasing labor shortages and land-use shifts from grain production to cash crops.”

Among the diseases, He mentioned sharp eyespot, fusarium head scab and yellow rust. New races of stem rust could potentially cause a problem if they crossed the Himalayas, He said.

Wheat rust a challenge in China

Stripe rust is a growing problem in Northwestern China, in the provinces of Gansu, Shaanxi, Sichuan, Chongqing, Yunnan, Hubei, and southern Henan.

According to Zhensang Kang, of the wheat pest control lab at Northwest A&F University in China, losses from stripe rust can run 10-50% per year.

Speaking at a press conference before the BGRI meeting, Kang said, “Yellow rust can over-summer and over-winter in certain regions, leading to epidemic infections.

"Barberry, an alternate host, particularly in the highlands, poses a threat of infection from both yellow rust and stem rust.”

Kang will participate in a panel discussion at the BGRI Workshop on “The Barberry Connection,” on September 3.

“Potentially huge yield losses due to yellow rust nationwide are only mitigated by intense disease monitoring and forecasting, and timely use of fungicides,” said Kang.

He blamed the “boom and bust” rust cycles on virtual monocultures of single resistance genes.

Speaking of stem rust, Kang noted that: “Based on 2007 figures, 700 Chinese cultivars and lines were tested in the stem rust nurseries at the Kenyan Agricultural Research Institute in Njoro, in Kenya.

"At that time, four lines were highly resistant, 10 were moderately resistant, and 686 genotypes were highly susceptible.”

New races of stem rust were discovered in Africa in 2008 and have since evolved and spread throughout East Africa, across to Yemen, potentially threatening the bread baskets of Central and South Asia, including India and China.

Stem rust can act like a “biological firestorm,” according to Coffman.

“Overnight, it can turn fields of wheat into blackened stubble with no grain.”

Like Norman Borlaug before him, Coffman is a staunch advocate for preparedness and for breeding resistance into wheat that is based on more than single resistance genes.

He noted that although stem rust is not currently a major issue in China, yellow rust is.

“China’s wheat varieties are highly susceptible to both rusts,” said Coffman. “Considering their resistance to rusts and other diseases, we would welcome China to be more pro-active in screening lines for rust resistance at the stem rust screening nurseries in Africa and to partner more with the Durable Rust Resistance in Wheat project and the Borlaug Global Rust Initiative.”

Holding the 2012 BGRI Technical Workshop in China is one way to build collaborative partnerships with the Chinese, according to Coffman.

“In nearly every lab in the world, there is a Chinese scientist,” he said.

“The Chinese are a very collaborative people.

"We would welcome the Chinese to take more of a leadership position in building durable resistance to both stem rust and yellow rust in the Chinese varieties of wheat.”

Scientists from every region of the world are attending the meeting in Beijing, which was organized by the Durable Rust Resistance in Wheat (DRRW) project for the Borlaug Global Rust Initiative (BGRI).

Funded by the Bill & Melinda Gates Foundation and the UK Department for International Development, the DRRW is managed by Cornell University. Partners include CIMMYT, the Syria-based International Center for Agricultural Research in the Dry Areas (ICARDA), the Food and Agriculture Organization of the United Nations (FAO), and the Indian Council of Agricultural Research (ICAR), among others.

Both CIMMYT and ICARDA are supported by the Consultative Group on International Agricultural Research (CGIAR).

For more information, call 607-227-5920.

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