Wheat ranks as a primary source of food and livelihood for hundreds of millions of people globally, especially in developing countries. But scientists are concerned that a newly discovered strain of one of the most dangerous pathogens to affect wheat could cause a global food crisis. First discovered in Uganda in 1999, Ug99 is a variant of the wheat pathogen known as stem rust, and expectations are that it will spread from its origin in eastern Africa to the rest of the wheat-growing world.

Until the advent of science-engineered agriculture, world wheat harvests were largely threatened by rapidly evolving fungal pathogens, among the most damaging of which was stem rust.

Over the past 150 years, stem rust pandemics have led to famines in India and massive grain losses in North America.

Modern breeding methods, combined with free international exchange of experimental wheat lines, have now led to the development and distribution of wheat varieties that have the ability to resist rust.

An "Expert Panel on the Stem Rust Outbreak in East Africa," led by Dr. Ronnie Coffman, evaluated the threat of the new wheat stem rust variant, Ug99. Coffman presented the report of their study at a press conference held in Nairobi last September a day before the Global Rust Initiative (GRI) summit.

According to Coffman, professor at Cornell University's Department of Plant Breeding and Genetics, the scientific community must collaborate to avert the danger of this new pathogenic variant. Coffman, who chaired the expert panel of researchers, said focusing only on localized regions or countries cannot solve the problem.

"It is only a matter of time until Ug99 reaches across the Saudi Arabian peninsula into the Middle East, South Asia, and eventually East Asia and the Americas," said Coffman.

Dr. Ravi Singh, a scientist working with the International Maize and Wheat Improvement Center (CIMMYT), said that the disease was first discovered in Uganda in 1999. It later appeared in Kenya in 2001 followed by Ethiopia in 2003, showing its devastating potential to spread and destroy.

Director of the Kenya Agricultural Research Institute (KARI), Dr. Romano Kiome, said the Ug99 pathogen has exhibited a potential of 100 percent devastation potency, and efforts to control it through fungicides have proven costly.

As wheat is one of the most important food crops in the world, Coffman said any disruption in its supply would have serious consequences, especially in developing countries. One such country is Pakistan, said Coffman, "where wheat accounts for 60 percent of the calories and more than 40 percent of the protein in the average daily diet."

Wheat rust has been one of the most feared wheat diseases as far back as the Roman Empire. In the 1950s, stem rust savaged wheat crops in North America. Losses in the past have been as high as 70 percent.

The disease is caused by a fungus that spreads throughout the world by releasing its spores on the wind currents. Less dangerous strains of rust have previously spread from eastern Africa to as far as China. Rust spores can also be transported on the clothes and luggage of people traveling through contaminated areas.

According to Nobel Peace Prize winner Professor Norman Borlaug, wheat rust was widespread in American and Canadian wheat fields between 1951 and 1954. In response, a campaign to exchange genetically rust-resistant varieties was launched globally and this international collaboration ended in growing resistant wheat in 17 locations.

Dr. Borlaug won the Nobel award for a lifetime of efforts to alleviate world hunger, and has collaborated with scientists on the improvement of wheat and on adapting it to new lands.

The development of genetically engineered high-yielding wheat cultivars with high levels of resistance to stem rust saved the world from a potential famine in the 1950s and 1960s. "It was only with the breeding and distribution of varieties resistant to stem rust that the world's wheat supply was spared," said Borlaug. The geneticist and plant pathologist said the new strain of stem rust pathogen poses a serious threat to small-scale farmers who do not have enough financial resources to spray their crops more than once every season.

"Without an epidemic for the past 50 years, maybe we’ve become complacent. We must see that kind of international collaboration again," Borlaug pointed out. Coffman agreed that the scientific community must collaborate internationally; otherwise Ug99 will have a devastating effect. Potential losses to small scale farmers could be enormous and more serious than those that occurred 50 years ago.

Director General of CIMMYT, Dr. Masa Iwanaga, said they have already started working on the disease but this work must also be taken up globally. The loss of just a tenth of the global wheat supply as a result of this new strain would reduce the wheat harvest by 60 million tons, resulting in losses worth more than $US 9 billion, Iwanaga was reported as saying in an ICARDA (International Center for Agricultural Research in the Dry Areas) press release.

Ug99 has so far survived attempts to curtail it, according to the panel of experts. Since it is difficult to stop, the only option, especially for small-scale farmers, is to identify and develop resistant strains, explained Kiome, director of the Kenya Agricultural Research Institute.

A Global Rust Initiative (GRI) will have these recommendations as their mandate, creating an international partnership led by the International Maize and Wheat Improvement Center (CIMMYT), the International Center for Agricultural Research in the Dry Areas (ICARDA), the Kenyan Agricultural Research Institute (KARI) and the Ethiopian Agricultural Research Organization (EARO).

Among the measures recommended by the panel is the monitoring of wheat populations by means of trap nurseries. These nurseries use wheat varieties known to have resistant genes and test their reaction to rust disease. Data obtained from the reaction of these resistant varieties is used to identify the different forms of pathogen.

As the pathogen population changes itself to infect wheat cultivars with different resistant genes, variations in the pathogen population must be identified. This identification process must be done through race-analysis for the Kenya-Ethiopia region, adjacent areas and beyond, according to the panel.

Another recommendation is the establishment of warning systems based on data using the Geographical Information System, which coordinates data collected using satellite imagery and data collected at the fields.

The panel also recommended a breeding strategy that would incorporate diverse genetic resistance to Ug99 into the modern cultivars currently grown in North America and Asia before the new strain of pathogen migrates to those areas. DNA-marker assisted selection should be used where feasible.

Chemical intervention for short-term control would be equally important in curtailing the wheat disease, and should be employed by all producers, according to the recommendations.

Seed multiplication agencies and community-based organizations should also be encouraged to produce commercial seeds for the newly developed stem rust resistant varieties.

Baseline studies need to be made in crops, both infected and not, and impact studies carried out after the use of resistant varieties. Such studies would have to take into consideration alternative crops and livelihood systems, because of the socio-economic implications of the new disease on wheat-producing countries.

Human resources need to be augmented through training programs. Advanced degree training should be provided for people associated with the project, in addition to in-country practical courses and specialized courses outside the country.

Well-equipped laboratories and effective communication systems are also needed to address the new threat. Facilities for wheat research should therefore be established and strengthened in Ethiopia and Kenya.

Special support needs to be given to communication strategies to raise and maintain awareness of the stem rust problem, while enhancing communication among scientists and other concerned stakeholders

Appropriate advanced research institutes like the ones in North America and Australia should be engaged in the GRI that utilize their own resources, said the panel report. CIMMYT and ICARDA should receive additional resources from advanced research institutes and other donors to coordinate the GRI and meet their respective research responsibilities necessary to avert an epidemic.

"For once, Africa can help the rest of the world," said Dr Marianne Banzinger, the Director of CIMMYT's African Livelihoods Program. "There is time to make a difference. This is a chance we cannot afford to miss."