Cimmyt researchers examine wheat crops outside njoro // peter guest

Children of the Green Revolution

In East Africa, the legacy of Nobel laureate Norman Borlaug lives on in the fight against a virulent crop disease.

Seven thousand feet up in the Rift Valley town of Nakuru, a group of the world’s leading wheat experts gather by the pool in the Merica Hotel.

Around a table cluttered with empty Tusker bottles are Ronnie Coffman, a big, bearded Kentuckian and chairman of Cornell University’s Centre for Plant Breeding; Gordon Cisar, a Wisconsin native and 20-year veteran of the US seed industry: Ravi Singh, from India, but now heading the wheat programme at Mexico’s Cimmyt research centre; and the Australian Bob McIntosh, described fondly by his colleagues as the planet’s greatest wheat pathologist—and a “crusty old bastard”.

Between them, they represent probably the greatest concentration of knowledge about wheat diseases, and in particular a virulent—but neglected—pathogen, Puccinia graminis, more commonly known as stem rust.

A fungus, stem rust attacks the stalk of cereal crops, causing severe reductions in yields, and in extreme cases the death of the plants. In the 1920s and again in the 1950s, stem rust hit U.S. wheat, destroying more than a fifth of the total crop in the worst years.

It was the father of the Green Revolution in Mexico and India, the Nobel Peace Prize winning agronomist Norman Borlaug, who, in the 1940s and 50s, led a concerted effort to breed resistant varieties.

Borlaug, who died in 2009, is credited with transforming the global food supply through his expertise in plant breeding, most prominently in Mexico. His success in targeting stem rust also bred a degree of complacency, according to Singh.

“People did such a good job of breeding resistance, that like other diseases, like plague or polio, it was kind of gone,” he says. “With pathogens they are sitting somewhere, they are still evolving, and they will come back. But no one puts money [for research] there because it is not seen as an immediate issue. Very often we are doing damage control. We don’t plan ahead for what is coming.”

In 1998, stem rust came back. Researchers in Uganda sent samples of a fungus found on wheat crops in East Africa for analysis by researcher Zak Pretorius in South Africa. It was not until the following year that the gravity of the find was established. Using the nomenclature of pathogen classification, the mutant species was dubbed according to its place of origin and the year of its identification—Ug99. The fungus was able to overcome the genetic resistance bred into the world’s wheat by Borlaug and his successors. As much as 90 percent of the global crop was vulnerable.

Before long, spores had reached Kenya and, crucially, Ethiopia—where, unlike much of Africa, wheat is a staple crop. Carried in the wind, the spores have kept spreading.

“It’s present all the way up the east coast of Africa, from South Africa to Yemen,” Coffman says. “It jumped the Red Sea into Yemen about five years ago, and it has had an incursion into Iran. It is basically poised in both the Northern and Southern hemispheres to move into other continents. It could move into South Asia, which could be tragic if they’re not ready for it. It could move to Central Asia, where very little has been done to prepare for it, and into China, which is the largest wheat growing country in the world.”

The potential impact on the developing world could be colossal. Earlier this month the UN warned that falling production and growing demand were seeing food prices rising, putting even greater pressure on the poor. In Africa, many countries import wheat to supplement their production of other staples, leaving them exposed to high prices on the international market. Some are now attempting to increase domestic production, but with the specter of a stem rust epidemic hanging over them, this seems a difficult prospect.

However, there is hope. Singh and his team have been identifying genes which confer resistance to the pathogen. At a test site at Njoro, near Nakuru, the fruits of their labour, and test crops from around the world, are being grown. In plots surrounded by stunted wheat infected with rust, the researchers have developed a number of plants that are able, to varying degrees, to survive the epidemic. With funding from USAID, they have deployed test crops to Ethiopia, Egypt and several Asian countries, and the resistant stock in vulnerable countries is growing.

In a classroom at the Kenya Agricultural Research Institute in Njoro, a group of students, newly trained in recognizing and containing the disease, wait to be handed graduation certificates. Scientists from Pakistan sit with those from India, Americans with Iranians. The disease does not respect borders, so those fighting it have had to learn to talk to each other. This ability of the world’s agronomists to cooperate despite the complexities of international politics was always a huge part of Borlaug’s credo, Coffman says.

At the heart of the 21st century response to stem rust have been Borlaug’s direct “descendants”. Coffman was the Nobel winner’s only PhD student. The Cimmyt centre in Mexico—Borlaug’s legacy—was at the centre of breeding and disseminating information. Around the tables in Nakuru, and in the field in Njoro, “Norm” is a name that resonates. It was Borlaug who, before his death, used his political clout and influence, at Coffman’s request, to approach the Gates Foundation for funding to scale up the Njoro research centre. The UK’s Department for International Development has since also contributed. Without this funding, it is hard to see where the response to the evolving crisis would have come from.

“The corporate and political memory of a wheat crop is last year’s crop. When you have these problems of an epidemic with a probability of one year in 15 or one year in 20, there’s no real political interest,” McIntosh says. Without political interest, there is no cash for research, he adds.

“The researchers are attracted to money. If there’s no money in the pot, the researchers go wandering off. You’ve got to remember that money stimulates research. When this [UG99 epidemic] started, probably in the world there were five or six serious stem rust workers.”

In Njoro, it is something that is worrying the group. As Coffman says, “The bigger issue is the status of public research capacity in agriculture worldwide.”

With both US and UK public funding for agricultural research drying up under the Reagan and Thatcher governments, the private sector took on the burden of crop science. Wheat farmers tend to store their own seed, meaning that big seed companies have little interest in the crop.

“Vast wealth is in private hands, that’s where our money is going to come from,” Coffman says. “There is a whole new way of generating public goods. It remains to be seen if it’s going to be adequate.”

Among the agronomists, there is a grim consensus that, even though there has been a brief flurry of activity, and their work has progressed rapidly, that the interest could be fleeting—until the next new mutant pathogen. Their success is a problem in itself. “If we get it right,” Cisar muses. “No one will hear about it.”