Gates Foundation moves to fight killer wheat disease

The Bill & Melinda Gates Foundation has given US$26.8 million to Cornell University in the USA for a new global project to fight wheat (stem) rust disease, which specialists say poses a threat to world food security.

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“International coordinated action is the only possible way to address problems of this magnitude. This project is a step towards re-invigorating and focusing such coordination,” Rick Ward, the project coordinator, told IRIN on 2 April.

According to a Cornell University press release, “the Durable Rust Resistance in Wheat project [launched on 2 April] will bring together 15 partner institutions to combat the emergence of deadly new variants of stem rust that can spread quickly, reducing healthy wheat to broken, shrivelled stems.”

Wheat represents about 30 percent of the global production of grain crops and, according UN Food and Agriculture Organization (FAO) projections, 598 million tonnes of wheat will be harvested in 2008 on 220 million hectares.

On average, each person in the world consumes 68.2 kilograms of wheat each year - about 630 calories per person per day, or between a third and a half of the minimal energy requirements of most adults.


Photo: David Swanson/IRIN
On average, each person in the world consumes 68.2 kilograms of wheat each year - about 630 calories per person per day


As a result of crop shortfalls in major wheat producing countries, largely due to extreme weather events in 2007, global wheat stocks plummeted, and wheat prices quadrupled - in part also due to rising oil prices and the use of land for biofuels. Poor consumers in Africa, Asia and parts of the Middle East are particularly vulnerable to price increases. Africa imports over 80 percent of its wheat needs (about nine million tonnes a year) - and the gap is projected to increase steadily in the future.

According to the project document: “By using a very conservative estimate of 10 percent loss in regions hit by Ug99, annual global losses by the year 2016 are predicted at 25 million tonnes (equivalent to about $8.3 billion at today’s prices).” This has huge implications for the rural and urban poor for whom bread is a dietary staple.

The project’s largest target market are the 50 million wheat-farming families in the Indo-Gangetic plain who stand to lose over seven million tonnes of annual production ($2.3 billion) for each 10 percent drop in yield.

“The reality could be much more frightening since much higher losses are possible. Between Rabat and Vladivostok, there are over 100 million hectares of wheat under cultivation, all genetically susceptible to Ug99,” says the project document.

Improved wheat varieties

One way of combating stem rust is by using fungicides but these are expensive (estimated at $40 per crop cycle to protect one hectare in Kenya) and they can pose risks to human health and the environment, according to scientists.


Photo: IRIN
A close up of wheat stem rust.

The project will, therefore, develop improved rust-resistant wheat varieties to protect global wheat production from the new variants of stem rust disease which are evolving in east Africa. New derivatives of Ug99 were isolated in Njoro, Kenya, in 2006 and 2007, and it is hoped that these can help in the development of more resistant wheat strains, according to Cornell University’s College of Agriculture and Life Sciences.

The Ethiopian Institute for Agricultural Research and the Kenya Agricultural Research Institute are expected to be the key bodies to develop the new resistant varieties, in collaboration with scientists at the International Maize and Wheat Improvement Centre known by its Spanish acronym CIMMYT, in Mexico; the International Centre for Agricultural Research in the Dry Areas (ICARDA), in Syria; and the International Rice Research Institute (IRRI) in the Philippines.

There will also be input by FAO and advanced research laboratories in the USA, Canada, China, Australia and South Africa. A project management unit will be based at Cornell University under the direction of Ronnie Coffman, international professor of plant breeding at the university.

Travellers can spread Ug99

Stem rust Ug99 is migrating out of east Africa via airborne spores which can also be spread by international travellers on their clothing. A similar rapid spread by human transport has been documented for other plant diseases, including yellow rust (another wheat disease).

According to the project document, a limited number of stem rust resistant (Sr) genes from various wheat varieties, landraces (ancient varieties) and wild relatives are available to breeders. “Some of these sources of resistance are ‘minor’ genes that are additive and need to be deployed together in one variety to provide effective protection (also known as Adult Plant Resistance, APR),” says the document. Some elite high-yielding breeding lines with resistance are already being tested in several countries.

Scientists at the project say they will adopt multiple approaches to achieve long-lasting stem rust resistance, from “bread and butter” breeding, to marker assisted selection (MAS) and high-end basic science explorations.

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