CIUDAD OBREGÓN, MEXICO (26 MARCH 2014)–Wheat farmers in East Africa and
the Middle East are on alert after a damaging strain of a plant disease
called stem rust decimated more than 10,000 hectares of wheat in southern
Ethiopia, the largest wheat producer in Sub-Saharan Africa (SSA), according
to a report discussed today at an international gathering of the world’s
top wheat experts.
The details of the stem rust outbreak in Ethiopia’s Bale zone is a
prominent topic at the Borlaug Global Rust Initiative (BGRI) 2014 Technical
Workshop. Together with the Borlaug Summit on Wheat for Food Security from
25-28 March, the BGRI is celebrating the 100th anniversary of the birth of
Dr. Norman Borlaug, a legendary scientist who developed high-yielding,
semi-dwarf wheat that is credited with sparking the Green Revolution and
saving over one billion people from starvation.
“Dr. Borlaug taught us that rust never sleeps, which is why we now have the
capabilities to detect an outbreak like the one that has occurred in
Ethiopia, and to quickly mobilize a global response,” said Ronnie Coffman,
professor of plant breeding and genetics at Cornell University, and
director of the Durable Rust Resistance in Wheat (DRRW) project. He noted
that the global consortiums Borlaug helped organize late in his life – now
known as the Borlaug Global Rust Initiative and the DRRW project – have
been key to aggressive rust intervention in Ethiopia.
Detective work by the International Maize and Wheat Improvement Center
(CIMMYT), DRRW, the Ethiopian Institute of Agricultural Research (EIAR),
the USDA-ARS Cereals Disease Laboratory in Minnesota and the Global Rust
Reference Centre (GRRC) in Denmark have revealed that the strain of stem
rust damaging wheat in Ethiopia is possibly similar to a strain found in
Turkey since 2007 and in Egypt and Germany in 2013. However, the pathogen
did not have a noticeable impact on production in these areas.
According to David Hodson, a senior scientist with CIMMYT’s Global Cereal
Rust Monitoring Program, the previous lack of damage could mean that wheat
varieties under cultivation there are resistant to an infection, there were
slight differences in the strains, or that environmental conditions have
not been conducive to a stem rust outbreak. (Though Hodson said wheat
experts were surprised to see stem rust of any type in Germany, where the
pathogen has not been detected for decades.)
But during the 2013 growing season in Ethiopia, the strain was lethal to a
popular variety of bread wheat called Digalu. Like other stem rusts, the
disease produced brick-red blisters on the plant and caused grains to
shrivel. Ironically, Digalu gained popularity in Ethiopia because it
carries resistance to other strains of stem rust and to another wheat
disease known as yellow or stripe rust. And these qualities have helped
wheat farmers in the country produce record harvests.
“With such widespread planting of Digalu, we have not seen the major yellow
rust outbreaks that were a problem in recent years and most farmers in
Ethiopia have enjoyed bumper crops this season,” said Bekele Abeyo, a
senior scientist and wheat breeder at CIMMYT. “But the widespread planting
of Digalu may have opened the door for the incursion of a new and
destructive strain of stem rust.”
Abeyo said that at the time of the stem rust outbreak in late 2013 the
wheat crop was at a vulnerable stage only in the southern part of Ethiopia.
Concern now turns, he said, to regions where farmers may already have begun
planting for the short rainy season that runs from February/March to
June/July, and are probably still using the now vulnerable Digalu variety.
Wind models indicate the disease also could spread in a southwesterly
direction toward Kenya, Uganda, Tanzania, Rwanda and – less probably – to
countries in the Middle East. Efforts are underway to identify varieties
being cultivated in these areas that might be susceptible to the strain of
stem rust causing problems in Ethiopia. Officials report that a variety
popular in Kenya called “Robin” is likely to be vulnerable, but, to date,
there have been no confirmed reports of the Ethiopian stem rust strain in
Kenya.
Dr. Bedada Girma, DRRW-Ethiopia coordinator, said working with farmers and
other stakeholders to replace vulnerable varieties with resistant varieties
is a high priority. But he said it will be a challenge to obtain enough
seed before farmers move ahead with their next planting. Ethiopian
agriculture officials also are advising farmers about how to properly use
fungicides to control an outbreak.
Borlaug Legacy: A World Well-Prepared for a Mutating Pathogen
Stem rust has long been a major threat to wheat, which is a key source of
calories and protein for 4.5 billion people in 100+ countries – more than
half of them wheat-dependent poor who live on less than US$2 per day.
Borlaug’s signature achievement was the development and dissemination of
high-yielding, stem rust-resistant semi-dwarf wheat, which helped launch
the Green Revolution in farm production in Asia and Latin America. The
resistance Borlaug and co-workers pioneered held up for decades, until it
succumbed to a new strain of stem rust known as “Ug99,” identified in
Uganda in 1999. The researchers noted that the stem rust detected in
Ethiopia is not a Ug99 strain and noted that Ethiopian farmers have been
aggressive in adopting new wheat varieties, like Digalu, that are resistant
to both yellow rust and the Ug99 strains.
Wheat experts at the Mexico meetings noted that the stem rust outbreak in
Ethiopia, while a cause for concern, needs to be seen in the context of a
world in which there is now a strong global network of wheat researchers
capable of responding quickly to emerging threats by rapidly developing new
disease-resistant varieties. In fact, Ethiopia is often cited as a model
for the potential to dramatically improve wheat yields in SSA, even though
production is scattered across millions of small farms that are less than
one hectare in size.
According to Girma, just a few years ago, most of the wheat cultivated in
Ethiopia was susceptible to either the Ug99 stem rust strains or to various
strains of yellow rust. Now, most of Ethiopia’s wheat is resistant to one
or both diseases. And the results can be seen in harvests that in 2004 and
2005 averaged 1.5 tons per hectare (t/ha), but now average about 2.37 t/ha.
In some areas, Ethiopian farmers have even been harvesting 5 to 8 t/ha.
“Smallholder farmers in Ethiopia are getting much better yields than they
used to,” said Hodson. “That’s an incredible advance and exactly what Dr.
Borlaug envisioned – that if you provide farmers in developing countries
with high-yielding, disease-resistant wheat, they can begin to create the
same kind of bread baskets that you see in developed countries.”
CIMMYT scientists believe many African countries are realizing only a small
fraction of their wheat production potential. They are looking for ways to
close the wheat yield gap and reduce the huge dependency on costly foreign
imports. In 2012, CIMMYT and the International Food Policy Research
Institute conducted an in-depth analysis of wheat prospects for SSA that
found farmers in the region may only be growing about 10 to 25 percent of
what is biologically possible and economically profitable. Such studies are
attracting the attention of policy-makers, as ministers of agriculture from
across Africa recently endorsed wheat as a strategic food security crop for
the continent.
“The recent stem rust outbreak shows that rust preparedness is an ongoing
‘arms race.’ As pathogens evolve, new varieties must be developed,” said
Coffman. “The East African highlands are hot spots for rust, but for all
countries in Sub-Saharan Africa – where food security is such an issue – it
is important that we continue to invest in the kinds of agricultural
development partnerships that bring results.”
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About Dr. Borlaug
Norman Ernest Borlaug (25 March 1914 – 12 September 2009) was an American
biologist, humanitarian and Nobel Peace Prize laureate who many consider
“the father of the Green Revolution,” “agriculture’s greatest spokesperson”
and “the man who saved a billion lives.” He is one of only seven people to
be awarded the Nobel Peace Prize, the Presidential Medal of Freedom and the
Congressional Gold Medal. Borlaug was also awarded India’s second-highest
civilian honor, the Padma Vibhushan. On March 25, 2014, a statue of Dr.
Borlaug will be unveiled in the US Capitol’s National Statuary Hall. It
will be one of two statues representing the State of Iowa.
Dr. Borlaug began his groundbreaking work on wheat in 1943 during his
tenure on a joint Government of Mexico-Rockefeller Foundation program to
make Mexico food self-sufficient. (This program was the precursor to
CIMMYT.) In the mid-1950s Borlaug led the introduction of his high-yielding
varieties combined with modern agricultural production techniques; as a
result, Mexico became a net exporter of wheat by 1963.
Borlaug’s wheat seeds were sent to India, Pakistan and Turkey in the early
1960s, at a time when Pakistan and India were on the verge of famine.
Between 1965 and 1970, wheat yields nearly doubled in these countries,
greatly improving their populations’ food security. These collective
increases in yield were termed the Green Revolution. Later in his life, he
helped apply these methods of increasing food production to Asia and
Africa. Dr. Borlaug worked at CIMMYT for more than 43 years.
About CIMMYT
Headquartered in Mexico, the International Maize and Wheat Improvement
Center (CIMMYT) is the global leader in research for development in maize
and wheat – two of the world’s key staple crops – and wheat- and
maize-based farming systems. CIMMYT works throughout the developing world
with hundreds of partners to sustainably increase the productivity of maize
and wheat systems to improve global food security and livelihoods.
Improved CIMMYT-derived wheat is sown on more than 60 million hectares in
developing countries – over 70 percent of the spring wheat area planted
with modern wheat varieties in those nations. These wheat varieties are
responsible for bigger harvests that bring annual added benefits to farmers
of at least US $500 million.
CIMMYT is a member of CGIAR and receives support from national governments,
foundations, development banks and other public and private agencies.
About BGRI
The Borlaug Global Rust Initiative (BGRI) is an international consortium of
over 1,000 scientists from over 20 institutions working together to reduce
the world’s vulnerability to stem, yellow and leaf rusts of wheat;
facilitate sustainable international partnerships to contain the threat of
wheat rusts; and enhance world productivity to withstand global threats to
wheat security.
Key components of the BGRI include systems for: cereal rust monitoring and
surveillance; gene discovery; improved testing, multiplication and adoption
of replacement varieties; training and capacity building; understanding
non-host resistance to stem rust; and increasing levels of investments and
coordination in wheat rust research and development.
The BGRI was championed by Norman E. Borlaug, and initiated by ICAR,
ICARDA, CIMMYT, FAO and Cornell University. It is fostered by the Durable
Rust Resistance in Wheat project, which serves as the secretariat of the
BGRI, and was established in 2008.