Deadly strain of wheat stem rust disease surfaces in Europe

Scientists have shown that the first appearance of wheat stem rust disease in the U.K. in nearly 60 years, which occurred in 2013, was caused by the same virulent fungal strain responsible for recent wheat stem rust outbreaks in Ethiopia, Denmark, Germany, and Sweden.

Wheat stem rust was reported by the Greeks and Romans, and the latter sacrificed to the gods to avoid disease outbreaks on their wheat crops. Photo: CIMMYT/Petr Kosina

Wheat stem rust was reported by the Greeks and Romans, and the latter sacrificed
to the gods to avoid disease outbreaks on their wheat crops.
Photo: CIMMYT/Petr Kosina

As reported today in Communications Biology, an international team of researchers led by the John Innes Centre, U.K., found that 80 percent of U.K. wheat varieties are susceptible to the deadly stem rust strain. The group also confirmed for the first time in many decades that the stem rust fungus was growing on barberry bush, the pathogen’s alternate host, in the UK.

“This signals the rising threat of stem rust disease for wheat and barley production in Europe,” said Dave Hodson, senior scientist at the International Maize and Wheat Improvement Center (CIMMYT) and co-author on the study.

A scourge of wheat since biblical times, stem rust caused major losses to North American wheat crops in the early 20th century. Stem rust disease was controlled for decades through the use of resistant wheat varieties bred in the 1950s by scientist Norman Borlaug and his colleagues. Widespread adoption of those varieties sparked the Green Revolution of the 1960s and 70s.

In 1999 a new, highly-virulent strain of the stem rust fungus emerged in eastern Africa. Spores of that strain and variants have spread rapidly and are threatening or overcoming the genetic resistance of many currently sown wheat varieties. Scientists worldwide joined forces in the early 2000s to develop new, resistant varieties and to monitor and control outbreaks of stem rust and yellow rust, as part of collaborations such as the Borlaug Global Rust Initiative led by Cornell University.

Barberry is a shrub found throughout the temperate and subtropical regions. Photo: CIMMYT archives

Barberry is a shrub found throughout
the temperate and subtropical regions.
Photo: John Innes Centre

The Communications Biology study shows that 2013 U.K. stem rust strain is related to TKTTF, a fungal race first detected in Turkey that spread across the Middle East and recently into Europe. It was the dominant race in the 2013 stem rust outbreak in Germany and infected 10,000 hectares of wheat in Ethiopia’s breadbasket the same year.

Because disease organisms mutate quickly to overcome crop resistance controlled by single genes, researchers are rushing to identify new resistance genes and to incorporate multiple genes into high-yielding varieties, according to Ravi Singh, CIMMYT wheat scientist who participated in the reported study.

“The greatest hope for achieving durable resistance to rust diseases is to make wheat’s resistance genetically complex, combining several genes and resistance mechanisms,” Singh explained.

Barberry, which serves as a spawning ground for the stem rust fungus, was largely eradicated from the U.K. and U.S. last century, greatly reducing the spread and genetic diversification of rust disease races. Now barberry is being grown again in the U.K. over the last decade, according to Diane G.O. Saunders, John Innes Centre scientist and co-author of the study.

“The late Nobel laureate Norman Borlaug said that the greatest ally of the pathogen is our short memory,” Saunders stated. “We recommend continued, intensive resistance breeding. We would also welcome work with conservationists of endangered, barberry-dependent insect species to ensure that planting of common barberry occurs away from arable land, thus safeguarding European cereals from a large-scale re-emergence of wheat stem rust.”

Click here to read the John Innes Centre media release about the Communications Biology report and view the report.

Goat grass gives wheat breeders an edge

31 January 2018
by Laura Strugnell

A commentary published on 30 January in the leading science journal Nature Plants highlights the importance of an ancient grass species for wheat breeding. The commentary was sparked by the recent publication of a reference genome from Aegilops tauschii, also called goat grass.

Bread wheat was created some 10,000 years ago by a natural cross of more simple, primitive wheats with a sub-species of goat grass. As such, goat grass genes constitute a major component of the very large wheat genome. The sequencing of goat grass DNA opens the way for wheat breeders to apply a number of advanced approaches to improve the speed and precision of wheat breeding for important traits that may be found in the goat grass segment of the wheat genome.

The International Maize and Wheat Improvement Center (CIMMYT) and the International Centre for Agricultural Research in the Dry Areas (ICARDA) have produced many wheat x grass crosses, recreating the original, natural cross but using other goat grass species and thus greatly expanding wheat’s diversity. Wheat lines derived from those crosses have since been used in breeding programs worldwide and have helped farmers to boost yields by up to 20 percent. Goat grass is known for being highly adaptable and disease tolerant, so the crosses endow wheat with similar qualities. Varieties from these crosses make up over 30 percent of international seed stores.

Researchers expect that the sequencing of this grass species’ DNA will facilitate advanced approaches such as “speed breeding” – a technique that uses controlled variables to achieve up to seven rounds of wheat crops in one year. This will help allow wheat breeding to keep up with the rising global demand for the crop and to address the challenges of new, virulent diseases and more extreme weather.

Read the Nature Plants article: The goat grass genome’s role in wheat improvement. 2018. Rasheed, A., Ogbonnaya, F.C., Lagudah, E., Appels, R., He, Z. In: Nature Plants.

Breakthrough in the battle against Ug99

Melania Figuroa and Peter Dodds
Thursday, January 25, 2018 (Posted on the Borlaug Global Rust Initiative web page)

Wheat stem rust at important flag leaf stage. Photo by Robert Park

A significant breakthrough in combatting wheat stem rust disease caused by the fungus Puccinia graminis f. sp. tritici was recently achieved through the combined work of an international collaborative team, showing the power of cooperative research approaches.

The emergence of the Ug99 race of stem rust in Africa and the Middle East together with the appearance of new strains in Europe catalyzed a major effort to identify new sources of stem rust resistance and breed these genes into wheat lines. However, the continued emergence of stem rust variants that overcome new resistance genes, now demands an increased focus on pathogen evolution and virulence mechanisms.

Numerous stem rust resistance (Sr) genes are known and in recent years several of these have been cloned and used to develop so-called ‘perfect’ markers to allow more rapid and accurate breeding. These genes typically encode immune receptors that recognize specific protein components of the fungal pathogen to trigger resistance. However, the molecules recognized by these Sr genes have been unknown until now, hampering our understanding of how new strains of P. graminis f. sp. tritici evolve to escape plant recognition.

New insight into this evolution came from the identification of the protein, AvrSr50, which is recognized by the wheat Sr50 resistance gene, by  an international collaboration led by Dr. Peter Dodds (CSIRO Food and Agriculture and University of Minnesota Adjunct Professor) and Professor Robert Park (University of Sydney and Director of theAustralian Cereal Rust Control Program) and involving teams in the UK and the US.

Click here to read the full article.

Emergency seed fuels quick farm recovery in drought-affected Ethiopia

In response to Ethiopia’s worst drought in 50 years and the country’s critical shortage of maize and wheat seed for sowing in 2016, Ethiopian organizations, seed producers, and the International Maize and Wheat Improvement Center (CIMMYT) partnered to deliver over 3,400 tons of high quality seed to farmers, which was sown on more than 100,300 hectares.

“This effort helped rescue the food security and livelihoods of more than 271,000 rural households and 1.6 million individuals in Ethiopia’s Amhara, Oromia, Tigray, and SNNP regions, and strengthened seed systems to address future climate, disease, and pest crises,” said Bekele Abeyo, CIMMYT wheat scientist who led the seed relief initiative.

Funded by the U.S. Agency for International Development (USAID) and Office of Foreign Disaster Assistance (OFDA) of the U.S. Ethiopia mission, seed relief complemented international and national food aid, helping farm families to quickly grow crops after several seasons of erratic or failed rains in Ethiopia and the catastrophic 2015-16 El Niño droughts. At that time, more than 10 million people struggled to find food, as eastern Ethiopia faced crop losses from 50 to 90 percent of expected yields.

“We went three years without rain,” says farmer Usman Kadir, whose 1.5-hectare homestead in Wanjo Bebele village, Halaba Special Woreda, supports a household of 11 persons. “We were able to eat thanks to emergency food programs.” In 2017, Kadir used emergency maize seed to sow half a hectare and harvested 3 tons, getting his farm back on its feet. “If more new improved varieties come, we want to work with you and expand our farming operation.”

Photo: Atlabtamu/CIMMYT.

Usman Kadir. Photos here and above: CIMMYT/A.Habtamu.

Wheat and maize: Mainstays of food security

Agriculture provides 42 percent of Ethiopia’s GDP, 77 percent of employment, and 84 percent of exports. Subsistence, smallholder farmers predominate, making their living from less than two hectares of land. Wheat and maize are the most important crops for food security; they are also at the center of Ethiopia’s increasingly vibrant agricultural output markets and have been the focus in recent years of public investment to raise national production.

Maize and wheat production in Ethiopia depends on rainfall, making the unpredictable weather patterns caused by climate change exceptionally detrimental here. Various studies predict an average 30 percent reduction in farm incomes due to climate change impacts, including greater extremes in temperatures and rainfall (floods, droughts) and the emergence of new pest and disease strains. Research shows that reduced precipitation is already holding back wheat yields.

To address this, experts identified maize and wheat varieties suitable for drought-affected areas and highly resistant to prevalent crop diseases. Of the maize varieties, some 10 percent were quality protein maize, which carries enhanced levels of key amino acids for protein synthesis in humans.

“This effort also provided training for district and zonal development agents in crop protection, agronomy, drought mitigation practices, and seed systems,” said Abeyo. “Finally, five women seed producer associations received wheat seed threshers and a large union of farmer seed producer cooperatives received a maize sheller through the initiative. This equipment will greatly expedite their operations and contribute to the expanded and more reliable access of farmers to affordable, quality seed in the future.”

Partners and contributors

Emergency relief seed was sourced through diverse CIMMYT partnerships, including producers in the USAID-funded “Drought Tolerant Maize for Seed Scaling Project” (DTMASS) and “Wheat Seed Scaling Initiative.” Stakeholders included the Ministry of Agriculture and Natural Resources (MoANR), the Bureau of Agriculture and Natural Resources (BoANR), public and private seed companies/enterprises, farmer cooperative unions, federal and regional research institutes, and non-government organizations working in target areas. With funding from the Bill & Melinda Gates FoundationEthiopia’s Agricultural Transformation Agency (ATA) helped deliver seed to drought-affected districts and jointly organized training and workshops.

Click here to read a full report on the emergency seed relief initiative. 

Heat tolerant varieties for durum wheat farmers in Africa

Using non-GM molecular breeding techniques, ICARDA’s scientists developed a set of durum wheat varieties that can withstand up to 40°C heat along the Senegal River basin. If scaled up, the technology offers potential to fight hunger and help farmers adapt to rising temperatures.

Click here to read the report on the ICARDA web page.

Now available: 2016-17 Annual Report of the International Wheat Yield Partnership

Wheat breeding lines from the IWYP Hub at CIMMYT are out-yielding local checks in tests, validating the strategy of combining high biomass individuals with those that feature better grain filling attributes. The lines are being sent to public and private breeding programs worldwide. Read more about this and other exciting IWYP activities and outputs:

Annual Report

First blast resistant, biofortified wheat variety released in Bangladesh

Scientists inspecting plants for wheat blast infection, at a workshop in Bangladesh in February 2017. Photo: Chris Knight-Cornell.

DHAKA, Bangladesh (CIMMYT) — As wheat farmers in Bangladesh struggle to recover from a 2016 outbreak of a mysterious disease called “wheat blast,” the country’s National Seed Board (NSB) released a new, high-yielding, blast-resistant wheat variety, according to a communication from the Wheat Research Centre (WRC) in Bangladesh.

Called “BARI Gom 33,” the variety was developed by WRC using a breeding line from the International Maize and Wheat Improvement Center (CIMMYT), a Mexico-based organization that has collaborated with Bangladeshi research organizations for decades, according to Naresh C. Deb Barma, Director of WRC, who said the variety had passed extensive field and laboratory testing. “Gom” means “wheat grain” in Bangla, the Bengali language used in Bangladesh.

“This represents an incredibly rapid response to blast, which struck in a surprise outbreak on 15,000 hectares of wheat in southwestern Bangladesh just last year, devastating the crop and greatly affecting farmers’ food security and livelihoods, not to mention their confidence in sowing wheat,” Barma said.

Caused by the fungus Magnaporthe oryzae pathotype triticum, wheat blast was first identified in Brazil in 1985 and has constrained wheat farming in South America for decades. Little is known about the genetics or interactions of the fungus with wheat or other hosts. Few resistant varieties have been released in Brazil, Bolivia and Paraguay, the countries most affected by wheat blast.

The Bangladesh outbreak was its first appearance in South Asia, a region where rice-wheat cropping rotations cover 13 million hectares and over a billion inhabitants eat wheat as main staple.

Many blast fungal strains are impervious to fungicides, according to Pawan Singh, a CIMMYT wheat pathologist. “The Bangladesh variant is still sensitive to fungicides, but this may not last forever, so we’re rushing to develop and spread new, blast-resistant wheat varieties for South Asia,” Singh explained.

The urgent global response to blast received a big boost in June from the Australian Centre for International Agricultural Research (ACIAR), which funded an initial four-year research project to breed blast resistant wheat varieties and the Indian Council of Agricultural Research (ICAR), which also provided grant to kick-start the work in South Asia. Led by CIMMYT, the initiative involves researchers from nearly a dozen institutions worldwide.

Chemical controls are costly and potentially harmful to human and environmental health, so protecting crops like wheat with inherent resistance is the smart alternative, but resistance must be genetically complex, combining several genes, to withstand new mutations of the pathogen over time.

Key partners in the new project are the agricultural research organizations of Bangladesh, including the Bangladesh Agricultural Research Institute (BARI), and the Instituto Nacional de Innovación Agropecuaria y Forestal in Bolivia, which will assist with large-scale field experiments to select wheat lines under artificial and natural infections of wheat blast.

Other partners include national and provincial research organizations in India, Nepal and Pakistan, as well as Kansas State University (KSU) and the U.S. Department of Agriculture-Agricultural Research Services (USDA-ARS). The U.S. Agency for International Agricultural Development (USAID) has also supported efforts to kick-start blast control measures, partnerships and upscaling the breeding, testing and seed multiplication of new, high-yielding, disease resistant varieties through its Feed the Future project.

BARI Gom 33 was tested for resistance to wheat blast in field trials in Bolivia and Bangladesh and in greenhouse tests by the USDA-ARS laboratory at Fort Detrick, Maryland. International partnerships are critical for a fast response to wheat blast, according to Hans-Joachim Braun, director of CIMMYT’s Global Wheat Program.

“Worldwide, we’re in the middle of efforts that include blast surveillance and forecasting, studies on the pathogen’s genetics and biology, integrated disease management and seed systems, as well as raising awareness about the disease and training for researchers, extension workers, and farmers,” said Braun.

With over 160 million people, Bangladesh is among the world’s most densely populated countries. Wheat is Bangladesh’s second most important staple food, after rice. The country grows more than 1.3 million tons each year but consumes 4.5 million tons, meaning that imports whose costs exceed $0.7 billion each year comprise more than two-thirds of domestic wheat grain use.

WRC will produce tons of breeder’s seed of BARI Gom 33 each year. This will be used by the Bangladesh Agricultural Development Corporation (BADC) and diverse non-governmental organizations and private companies to produce certified seed for farmers.

“This year WRC will provide seed to BADC for multiplication and the Department of Agricultural Extension will establish on-farm demonstrations of the new variety in blast prone districts during 2017-18,” said Barma.

As an added benefit for the nutrition of wheat consuming households, BARI Gom 33 grain features 30 percent higher levels of zinc than conventional wheat. Zinc is a critical micronutrient missing in the diets of many of the poor throughout South Asia and whose lack particularly harms the health of pregnant women and children under 5 years old.

With funding from HarvestPlus and the CGIAR Research Program on Agriculture for Nutrition, CIMMYT is leading global efforts to breed biofortified wheat with better agronomic and nutritional quality traits. The wheat line used in BARI Gom 33 was developed at CIMMYT, Mexico, through traditional cross-breeding and shared with Bangladesh and other cooperators in South Asia through the Center’s International Wheat Improvement Network, which celebrates 50 years in 2018.

Stable window 1 and 2 (W1W2) funding from CGIAR enabled CIMMYT and partners to react quickly and screen breeding lines in Bolivia, as well as working with KSU to identify sources of wheat blast resistance. The following W1 funders have made wheat blast resistance breeding possible: Australia, the Bill & Melinda Gates Foundation, Canada, France, India, Japan, Korea, New Zeland, Norway, Sweden, Switzerland, the United Kingdom and the World Bank. The following funders also contributed vital W2 funding: Australia, China, the United Kingdom (DFID) and USAID.

Improved wheat helps reduce women’s workload in rural Afghanistan

Afghan women from wheat farming villages in focus-group interviews as part of Gennovate, a global study on gender and agricultural innovation. Photo: CIMMYT archives

by Katelyn Roett, Mike Listman / October 12, 2017

New research shows improved wheat raises the quality of life for men and women across rural communities in Afghanistan.

recent report from Gennovate, a major study about gender and innovation processes in developing country agriculture, found that improved wheat varieties emerged overwhelmingly among the agricultural technologies most favored by both men and women.

In one striking example from Afghanistan, introducing better wheat varieties alone reduced women’s work burden, showing how the uptake of technology – whether seeds or machinery – can improve the quality of life.

“Local varieties are tall and prone to falling, difficult to thresh, and more susceptible to diseases, including smuts and bunts, which requires special cleaning measures, a task normally done by women,” said Rajiv Sharma, a senior wheat scientist at International Maize and Wheat Improvement Center (CIMMYT) and country liaison officer for CIMMYT in Afghanistan. “Such varieties may comprise mixes of several seed types, including seed of weeds. They also give small harvests for which threshing is typically manual, with wooden rollers and animals, picking up sticks, stones, and even animal excrement that greatly complicates cleaning the grain.”

Both women and men spoke favorably about how improved wheat varieties have eased women’s wheat cleaning work.  “Improved seeds can provide clean wheat,” said an 18-year old woman from one of the study’s youth focus groups in Panali, Afghanistan. “Before, we were washing wheat grains and we exposed it to the sun until it dried. Machineries have [also] eased women’s tasks.”

Finally, Sharma noted that bountiful harvests from improved varieties often lead farmers to use mechanical threshing, which further reduces work and ensures cleaner grain for household foods.

Gennovate: A large-scale, qualitative, comparative snapshot

Conceived as a “bottom-up” idea by a small gender research team of CGIAR in 2013, Gennovate involves 11 past and current CGIAR Research Programs. The project collected data from focus groups and interviews involving more than 7,500 rural men and women in 26 countries during 2014-16.

Some 2,500 women and men from 43 rural villages in 8 wheat-producing countries of Africa and Asia participated in community case studies, as part of the CGIAR Research Program on Wheat.

“Across wheat farm settings, both men and women reported a sense of gradual progress,” said Lone Badstue, gender specialist at the CIMMYT and Gennovate project leader. “But women still face huge challenges to access information and resources or have a voice in decision making, even about their own lives.”

According to estimates of the Food and Agriculture Organization of the United Nations (FAO), if women farmers, who comprise 43 per cent of the farm labor force in developing countries, had the same access to resources as men, agricultural output in 34 developing countries would rise by an estimated average of as high as 4 percent.

“Gender-related restrictions such as limitations on physical mobility or social interactions, as well as reproductive work burden, also constitute key constraints on rural women’s capacity to innovate in agriculture,” Badstue explained.

Gender equity drives innovation

The Gennovate-wheat report identified six “positive outlier communities” where norms are shifting towards more equitable gender relations and helping to foster inclusiveness and agricultural innovation. In those communities, men and women from all economic scales reported significantly higher empowerment and poverty reductions than in the 37 other locations. Greater acceptance of women’s freedom of action, economic activity, and civic and educational participation appears to be a key element.

“In contexts where gender norms are more fluid, new agricultural technologies and practices can become game-changing, increasing economic agency for women and men and rapidly lowering local poverty,” Badstue said.

The contributions and presence of CIMMYT in Afghanistan, which include support for breeding research and training for local scientists, date back several decades. In the last five years, the Agricultural Research Institute of Afghanistan (ARIA) of the country’s Ministry of Agriculture, Irrigation & Livestock (MAIL) has used CIMMYT breeding lines to develop and make available to farmers seed of 15 high-yielding, disease resistant wheat varieties.

Read the full report “Gender and Innovation Processes in Wheat-Based Systems” here.

GENNOVATE has been supported by generous funding from the World Bank; the CGIAR Gender & Agricultural Research Network; the government of Mexico through MasAgro; Germany’s Federal Ministry for Economic Cooperation and Development (BMZ); numerous CGIAR Research Programs; and the Bill & Melinda Gates Foundation.