Posts Tagged ‘stem rust’

BGRI-led coalition protects world’s wheat crop

This story by Matt Hayes was originally published on the Borlaug Global Rust Initiative website.

When a novel strain of a wheat pathogen first emerged in East Africa in 1998, Norman Borlaug knew the world faced a dire threat to food security.

The virulent race of stem rust that became known as Ug99 was deadly to nearly all wheat varieties, threatening to cause epidemic losses in wheat fields around the globe. To combat the disease, the Borlaug and a team of committed scientists at Cornell, CIMMYT, ICARDA, FAO and other organizations sounded the global alarm in 2005. Those pioneers launched the Borlaug Global Rust Initiative (BGRI) to protect the global wheat supply against the spread of Ug99 and other challenges.

In a keynote speech delivered June 25 during the BGRI’s second virtual workshop, Ronnie Coffman, vice-chair of the BGRI, described those early efforts and the long-running scientific work to combat wheat disease.

The virtual “Take It to the Farmer” event featured videos and discussion with farmers and experts from around the wheat-growing world. Six wheat growers from five countries focused on the challenges they face — Felix Austin of F1 Seed in the UK, Hajo Mergo from Ethiopia, Deviprasad Aryal and Ramchandra Adhikari from Nepal, Esther Chelule from Kenya, Gurjeet Singh Mann from India, and Jesús Larraguibel Artola from Mexico. While wheat panelists discussed possible solutions  — Bill Angus from Angus Wheat in the UK; Hans Braun from CIMMYT, in Mexico; Anne Cichangi from KALRO, in Kenya; Bedada Girma, from EIAR, Ethiopia; Chhavi Tiwari from Shri Vaishnav Institute of Agriculture in India, and Vijay Vijayaraghavan from Sathguru Management Consultants in India.

According to Coffman, the world averted disaster thanks to the coordinated global effort led by Cornell’s BGRI with more than $100 million in funding for the Durable Rust Resistance in Wheat (DRRW) and Delivering Genetic Gain in Wheat (DGGW) projects from the Bill & Melinda Gates Foundation and UK aid from the British people.

The BGRI and the projects it managed was essential to protecting one of the world’s most important crops, according to Coffman.

Crucial outcomes from the DRRW and DGGW projects noted by Coffman include vast increases in land area planted to rust-resistant varieties, global expansion of a wheat pathogen surveillance network, more young wheat scientists in countries around the world — especially women — trained to be wheat breeders, pathologists, gender experts and project leaders, and the establishment of a global wheat community dedicated to the improvement of one of the world’s most important crops.

“For 12 years, through the DRRW and the DGGW projects, the BGRI has focused on delivering rust-resistant varieties of wheat to the farmers around the world who depend on agriculture and wheat production for their livelihoods,” said Coffman. “We have been especially dedicated to smallholder farmers in wheat-producing countries in Africa and Asia. Men and women who do not always have the access to new technologies — like improved seed — that they need.”

During the past 12 years, BGRI scientists have released more than 270 new varieties of wheat with greater resistance to diseases and environmental stresses such as climate change, working with national programs in 11 at-risk countries.

“These varieties have contributed enormously to improving the livelihoods of the farmers who adopted them,” Coffman said.

Maricelis Acevedo, associate director for science for DGGW, said that the successes were only possible by building a network of global researchers working in tandem with farmers on a common goal to secure the world’s wheat.

“Science and agriculture are forever linked in our enduring quest to feed the world,” Acevedo said. “The BGRI is committed to making sure scientific innovations help the world’s farmers prosper.”

One element of those efforts is robust surveillance of wheat pathogens. To track the spread of rust and other diseases, the BGRI expanded the international monitoring network from two countries in 2007 to 43 today. By utilizing precise location tagging equipment and mobile devices, “our partners now operate the world’s largest international crop disease monitoring system in the world,” said Coffman.

Mobile plant disease diagnostic technologies allow researchers to identify individual strains of complex fungal pathogens directly in the field, making it easier for farmers to quell outbreaks quickly. 

The projects also helped establish facilities needed to monitor and respond to diseases. Investments in greenhouses, irrigation systems, laboratories, field equipment and communications technology gave global partners the tools needed to collaborate with other wheat scientists around the world to breed more rust resistant wheat, and help farmers stay ahead of epidemics caused by evolving races of rust. At nursery facilities built in Ethiopia and Kenya, scientists are able to test elite wheat varieties from national wheat breeding programs around the world against various strains of rust.  

Long-term sustainability and durability depend on knowledgeable and dedicated scientists, according to Coffman. Since 2008, more than 1000 wheat scientists from countries around the world have been trained with funding from the projects, Coffman said.

“As we move forward, to 2030 and beyond, we must rededicate ourselves to understanding farmers’ needs because they are the ultimate beneficiaries of our work,” said Coffman.

“We will continue to build this coalition of great scientists committed to the big, big task of increasing food security one wheat field at a time,” said Acevedo, in her closing remarks.

The next BGRI Virtual Workshop will take place in October.

Watch Take It to the Farmer: https://www.youtube.com/watch?v=PSOdFDZUZrY&feature=youtu.be

Keep wheat diseases at bay: 11th annual training on stem rust note taking and germplasm evaluation at KALRO Njoro, Kenya

by Jerome Bossuet

Scientists at this year’s annual training on stem rust note taking and germplasm evaluation. Photo: CIMMYT

As part of the Delivering Genetic Gain in Wheat (DGGW) project, the International Maize and Wheat Improvement Center (CIMMYT) in collaboration with Kenya Agricultural & Livestock Research Organization (KALRO) and Cornell University recently trained 24 researchers (8 women & 16 men) from 9 countries across the world on wheat rust disease diagnosis and germplasm evaluation. The training took place on October 5-13, 2019 at the KALRO research station in Njoro, Kenya, where CIMMYT’s wheat breeding and rust screening facility is located.

Hands-on skills for efficient breeding and disease control

CIMMYT has held such hands-on trainings annually since 2009, benefitting over 220 scientists, mostly wheat breeders and pathologists from national programs of developing countries worldwide.

“These trainings aim at nurturing the next generation of wheat scientists in the different wheat growing areas, harmonizing cost-effective wheat breeding techniques and building a global community of practice, so important for our future food security,’’ said training coordinator, Mandeep Randhawa, Wheat Breeder and Wheat Rust Pathologist based at CIMMYT Kenya. Dr. Randhawa manages overall activities of the stem rust phenotyping platform Njoro.

The training focuses particularly on studying resistance to rapidly evolving fungal diseases like black (stem), yellow (stripe) and brown (leaf) rusts. CIMMYT’s Global Wheat Program in Africa uses such trainings to establish new partnerships and continue efforts in wheat breeding and combating emerging challenges across the different farming regions.

The participants learned how to record stem rust field notes to identify different types and levels of resistance, and the interaction with  wheat experts helped them better understand how wheat rust pathogens keep evolving. Continuous breeding of wheat varieties with not-only high yield potential but with resistance to rust and non-rust diseases was emphasized.    

An important skill the trainees gained during the course was to visually identify and score stem rust symptoms accurately. The percentage of rust coverage on the stem is used to score plants’ susceptibility, e.g. moderately susceptible (MS) or moderately resistant (MR) host reactions to infection.

“Harmonizing the way wheat breeders score stem rust severity in different countries like Ethiopia or Bangladesh is very important, so we could compare research data in any global breeding program like DGGW and for disease surveillance systems,’’ explained Emeritus Professor Robert McIntosh, one of the trainers from the Plant Breeding Institute-Cobbitty, University of Sydney, Australia.

Despite its importance to the global food and nutrition security, wheat remains susceptible to very destructive rust diseases. Rusts can lead to total crop failure when the climate conditions are favorable for the fungus and varieties grown by farmers are susceptible. The wheat scientific community has to remain vigilant on rust outbreaks globally as these pathogens evolve quickly. The stem rust race Ug99, reported for the first time in Uganda in 1999, was able to overcome the stem rust resistance gene Sr31 present in many popular varieties planted by farmers in the region. In 2013-14, wheat variety Digalu in Ethiopia and Robin in Kenya became susceptible to a new stem rust race with virulence to gene Srtmp. By 2019, fourteen different races in Ug99 lineage have been identified across Eastern and Southern Africa.

“You can train someone for one year to score for rust resistance, but you learn all your life,’’ added McIntosh. “In the era of molecular breeding, it is remarkable to see that visual phenotyping recognition still plays a strong role in safeguarding one of the most important cereal.”

“This is the first time I am doing this rust scoring. This will be important for my job of certifying new rust resistant wheat varieties, to know how to rank one wheat variety from other popular check,’’ noted seed health inspector, Philip Chemeltorit from the Kenya Plant Health Inspectorate Services (KEPHIS) Nakuru. A durum wheat breeder, Ms. Divya Ambati from Indore, India learned how the rust symptoms vary between durum and bread wheat germplasm, while wheat scientists, Ms. Sourour Ayed and Ms. Rifka Hammami, from Tunisia were more interested in how to tackle Septoria, another fungal disease prevalent in their country.

“This training course is a great opportunity for national programs to have first-hand information on the performance of their varieties and advanced lines evaluated at the phenotyping platform from respective countries. It is important to understand the different types of resistance that can be used in breeding. Strategies of combining different race specific and adult plant resistance (APR) genes is important for researchers to develop varieties with durable resistance,” said Sridhar Bhavani, Head of Wheat Rust Pathology at CIMMYT Mexico.

Back to the breeder’s equation

Developing and distributing rust resistant wheat varieties is regarded as the most cost-effective and eco-friendly control measure, especially in developing countries, where the majority are resource-poor smallholder farmers with limited access to fungicides to control the disease.

Ravi Singh, Head of Wheat Improvement at CIMMYT Mexico explained the new wheat breeding priorities, where breeders should focus on cost-effectiveness:

‘’Wheat scientists must go back to the blackboard how to increase genetic gains in a cost-effective way. What new methods and tools would increase the number of lines screened (intensity), with good accuracy and shorter breeding cycles?’’

CIMMYT Mexico for instance has just invested in a new large field greenhouse in Toluca research station to produce four generations of wheat annually, instead of two currently. The global wheat program will be more responsive to new pests and disease like the recent wheat blast outbreak that affected Bangladesh.

‘’But not all is about speed breeding,’’ warned Singh. “The wheat research should remain holistic and continue asking the right questions to well capture farmers and wheat processors’ needs when defining future breeding targets or product profiles. Wheat yield potential remain very important, but you have to ‘package other traits like water-use efficiency, disease resistance, nutrition, profitability etc.’’’

Godwin Macharia, Centre Director and Wheat Breeder of the KALRO- Njoro Centre discussed progress in wheat improvement through CIMMYT-KALRO partnership:

 “Wheat varieties Kenya Kasuku and Kenya Jacana with significant yield advantage over current commercial varieties and moderate levels of resistance to stem rust were released by KEPHIS in 2019. Moreover, several high-yielding rust resistant wheat lines are in the national performance testing towards identification and release of suitable varieties for commercialization in Kenya growing environments. Seed multiplication is in process with enough volumes of breeder seed of the new varieties available for further bulking and distribution to growers for cultivation in the 2020 season.’’

CIMMYT global partnership fights mutating wheat rust

Kenya research station offers a unique wheat science platform with global impact

By Joshua Masinde

KALRO staff selecting and taping promising wheat plants with resistance to stem rust disease at the wheat stem rust phenotyping facility in Njoro. Photo: Joshua Masinde/CIMMYT.

Stem rust, which occurs mainly in warm and humid conditions, is a serious biotic threat to wheat that can destroy healthy plants just a few weeks before harvest, resulting in huge yield losses to farmers. Along with leaf rust and stripe rust, it is the among the world’s most threatening wheat fungal diseases, dreaded by farmers for centuries.

Two decades ago, a virulent race of stem rust — identified as Ug99 — was identified in Uganda. The race went on to cause major epidemics in Kenya in 2002 and 2004. It continues to evolve and emerge into new races. Ug99 and its variants have since spread across East African highlands to South Africa, and to Yemen and Iran, threatening regional food security.

To tackle this stem rust pathogen, the International Maize and Wheat Improvement Center (CIMMYT) and Cornell University established the International Stem Rust Phenotyping Platform in Njoro, Nakuru County, Kenya, in collaboration with the Kenya Agricultural and Livestock Research Organization (KALRO) through the Durable Rust Resistance in Wheat (DRRW) project in 2008.

Stem rust resistant (left) and susceptible (right) wheat plants at the stem rust phenotyping facility in Njoro, Nakuru County in Kenya. Photo: Joshua Masinde/CIMMYT.

Over the past decade, wheat breeders and pathologists have worked collaboratively at the facility to stay ahead of this fast-evolving wheat stem rust fungus. This partnership has resulted in the release of over 150 wheat lines around the world, with resistance to Ug99 and its variants. The development of these high-yielding varieties suitable to various agro-ecologies has been possible with support from the Bill & Melinda Gates Foundation and the UK Department for International Development (DFID) initially through the DRRW project, and presently as part of the Delivering Genetic Gain in Wheat (DGGW) project, managed by Cornell University.

Phenotyping – the use of field-testing technology to identify desired plant traits – is a core component in the facility. The facility uses the CIMMYT Mexico-Kenya shuttle breeding system to quickly evaluate and select wheat lines for stem rust resistance. It also evaluates wheat germplasm from different countries, and “mapping populations” — crosses of diverse parents — to identify and characterize new sources of rust resistance.  

Shuttle breeding

The CIMMYT Mexico-Kenya shuttle breeding system allows breeders to plant at two locations to rapidly advance new plant generations and expose the wheat to different stresses (abiotic and biotic). Testing in Obregon yields wheat lines adaptable to different agro-ecological zones, and with resistance to local races of leaf rust and stem rust pathogen, while additional testing in Kenya enhances stem rust resistance to Ug99 and its variants. This enables the Njoro facility to screen and select about 1,500-2,000 segregating wheat populations over the course of two seasons.

“Through the CIMMYT Mexico-Kenya shuttle breeding, continuous testing of wheat germplasm, speed breeding and use of modern marker technologies for genomic selection, we innovate continuously to develop improved wheat lines with a package of desired traits in a much shorter period of time,” explained Mandeep Randhawa, CIMMYT wheat breeder and wheat rust pathologist.

Scientists at the facility evaluate about 10,000 lines from yield trials for stem rust resistance over two seasons. The best performing lines undergo second year of yield tests under five different environments in Obregon, Mexico:  full irrigation, drought, flat bed, raised bed and heat stress. Breeders then select and compile high-yielding lines and distribute them as international nurseries to national partners with the help of CIMMYT’s germplasm bank.

Wheat plants infested with stem rust. Photo: Joshua Masinde/CIMMYT.

The Njoro screening facility has a capacity of testing 50,000 wheat lines in a year. As many as 20 countries send their germplasm to the facility for stem rust evaluation. About 600,000 wheat lines have been evaluated at Njoro over the last 10 years.

The critical challenge for breeders is to combine all desirable traits into single lines in a shorter period: say five, instead of 10 years. Such elaborate breeding efforts require sustained support and international cooperation to develop high-yielding stress resilient lines suited to various agro-ecologies. 

Training and capacity building for researchers and national programs

The Njoro facility plays a major capacity-building role for partner scientists, and MSc and PhD students. CIMMYT trains and equips early career scientists to better prepare them to deal with possible new epidemics, with an annual training targeting 20-25 early-career scientists from across the world. Last year’s training took place on October 1-9, 2018, as part of the Bill & Melinda Gates Foundation- and DFID-funded DGGW project (under the “talent pipeline” objective) managed through Cornell University.

In the last decade, CIMMYT has trained over 200 scientists from national research programs.

“In addition to imparting knowledge on new techniques in wheat breeding and genetics,” said Mandeep, “we normally use such opportunities to train the scientists on evaluating germplasm for stem rust resistance and standardizing stem rust note taking.”

“With such a partnership, it is easier and more cost-effective to train our local wheat researchers as opposed to sending them to all the way to Mexico. We have had a good number of young scientists trained at this facility as a result of this valuable partnership with CIMMYT,” said Ruth Wanyera, principal research scientist at KALRO.

Strengthening national programs better prepares them to put improved lines to appropriate use in the field – a core mandate of CIMMYT accomplished through the Njoro facility.

Protecting the World’s Wheat – Delivering Genetic Gain in Kenya

In February 2019 filmmaker Chris Knight of International Programs at Cornell University’s College of Agriculture and Life Sciences visited the Kenya Agricultural and Livestock Research Organization – Food Crops Research Institute (KALRO – FCRI) research station in Njoro, Kenya.  Wanting to visually capture how Cornell is working with CIMMYT and a global partnership of more than 25 countries to protect the world’s wheat from diseases and the stress of climate change, he produced the short film Protecting the World’s Wheat – Delivering Genetic Gain in Kenya .

The film features East Africa, a center of genetic diversity for wheat stem rust, a fungal pathogen that causes significant yield losses worldwide. To combat this, partner countries test more than 50,000 experimental wheat lines against stem rust in Kenya every year at the Njoro research station to ensure that newly released wheat varieties will be resistant to emerging virulent races of the stem rust fungus as they evolve and spread.

Farmers and scientists have been fighting stem rust since the domestication of wheat thousands of years ago. This brilliant dance between humans and nature will likely never stop, but by working together we can stay one step ahead of this pesky pathogen. As Ruth Wanyera, Principal Research Scientist at KALRO stated, “(Stem rust) is running, and we’re also running. It’s running, and we’re also running. We have to do something to make sure there’s food in the table. That is where my motivation is. Let’s do something. Let’s feed the world. Let there be food for people to eat, or for people to survive.”

Pakistan wheat seed makeover: More productive, resilient varieties for thousands of farmers

Munfiat, a farmer from Nowshera district, Khyber Pakhtunkhwa province, Pakistan, is happy to sow and share seed of the high-yielding, disease resistant Faisalabad-08 wheat variety. (Photo: CIMMYT/Ansaar Ahmad)

Munfiat, a farmer from Nowshera district, Khyber Pakhtunkhwa province, Pakistan, is happy to sow and share seed of the high-yielding, disease resistant Faisalabad-08 wheat variety. (Photo: CIMMYT/Ansaar Ahmad)

Nearly 3,000 smallholder wheat farmers throughout Pakistan will begin to sow seed of newer, high-yielding, disease-resistant wheat varieties and spread the seed among their peers in 2019, through a dynamic initiative that is revitalizing the contribution of science-based innovation for national agriculture.

Some 73 tons of seed of 15 improved wheat varieties recently went out to farmers in the provinces of Baluchistan, Gilgit Baltistan, Khyber Pakhtunkhwa, Punjab and Sindh, as part of the Agricultural Innovation Program (AIP), an initiative led by the International Maize and Wheat Improvement Center (CIMMYT) with funding from the US Agency for International Development (USAID).

“Our main goal is to help farmers replace outdated, disease-susceptible wheat varieties,” said Muhammad Imtiaz, CIMMYT scientist and country representative for Pakistan who leads the AIP. “Studies have shown that some Pakistan farmers grow the same variety for as long as 10 years, meaning they lose out on the superior qualities of newer varieties and their crops may fall victim to virulent, rapidly evolving wheat diseases.”

With support from CIMMYT and partners, participating farmers will not only enjoy as much as 20 percent higher harvests, but have agreed to produce and share surplus seed with neighbors, thus multiplying the new varieties’ reach and benefits, according to Imtiaz.

He said the new seed is part of AIP’s holistic focus on better cropping systems, including training farmers in improved management practices for wheat.

Wheat is Pakistan’s number-one food crop. Farmers there produce over 25 million tons of wheat each year — nearly as much as the entire annual wheat output of Africa or South America.

Annual per capita wheat consumption in Pakistan averages over 120 kilograms, among the highest in the world and providing over 60 percent of Pakistanis’ daily caloric intake.

The seed distributed includes varieties that offer enhanced levels of grain zinc content. The varieties were developed by CIMMYT in partnership with HarvestPlus, a CGIAR research program to study and deliver biofortified foods.

According to a 2011 nutrition survey, 39 percent of children in Pakistan and 48 percent of pregnant women suffer from zinc deficiency, leading to child stunting rates of more than 40 percent and high infant mortality.

The road to better food security and nutrition seems straighter for farmer Munsif Ullah and his family, with seed of a high-yielding, zinc-enhanced wheat variety. (Photo: CIMMYT/Ansaar Ahmad)

The road to better food security and nutrition seems straighter for farmer Munsif Ullah and his family, with seed of a high-yielding, zinc-enhanced wheat variety. (Photo: CIMMYT/Ansaar Ahmad)

“I am very excited to be part of Zincol-16 seed distribution, because its rich ingredients of nutrition will have a good impact on the health of my family,” said Munsif Ullah, a farmer from Swabi District, Khyber Pakhtunkhwa province.

Other seed distributed includes that of the Pakistan-13 variety for rainfed areas of Punjab, Shahkar-13 for the mountainous Gilgit-Baltistan, Ehsan-16 for rainfed areas in general, and the Umeed-14 and Zardana varieties for Baluchistan.

All varieties feature improved resistance to wheat rust diseases caused by fungi whose strains are mutating and spreading quickly in South Asia.

CIMMYT and partners are training farmers in quality seed production and setting up demonstration plots in farmers’ fields to create awareness about new varieties and production technologies, as well as collecting data to monitor the varieties’ performance.

They are also promoting resource-conserving practices such as balanced applications of fertilizer based on infrared sensor readings, ridge planting, and zero tillage. These innovations can save water, fertilizer, and land preparation costs, not to mention increasing yields.

“CIMMYT’s main focus in Pakistan is work with national wheat researchers to develop and spread better wheat production systems,” Imtiaz explained. “This includes improved farming practices and wheat lines that offer higher yields, disease resistance, and resilience under higher temperatures and dry conditions, as well as good end-use quality.”

CIMMYT’s partners in AIP include the National Rural Support Program (NRSP), the Lok Sanjh Foundation, the Village Friends Organization (VFO), the Aga Khan Rural Support Program (AKRSP), the National Agricultural Research Council (NARC) Wheat Program, the Wheat Research Institute (WRI) Faisalabad and Sakrand centers, AZRI-Umarkot, Kashmala Agro Seed Company, ARI-Quetta, BARDC-Quetta, and Model Farm Services Center, KP.

(Photo: CIMMYT/Ansaar Ahmad)

(Photo: CIMMYT/Ansaar Ahmad)

Mutating diseases drive wheat variety turnover in Ethiopia, new study shows

Yellow spores of the fungus Puccinia striiformis f.sp. tritici, which causes stripe rust disease in wheat. Photo: CIMMYT/Mike Listman.

By Mike Listman

Rapidly emerging and evolving races of wheat stem rust and stripe rust disease—the crop’s deadliest scourges worldwide—drove large-scale seed replacement by Ethiopia’s farmers during 2009-14, as the genetic resistance of widely-grown wheat varieties no longer proved effective against the novel pathogen strains, according to a new study by the International Maize and Wheat Improvement Center (CIMMYT).

Based on two surveys conducted by CIMMYT and the Ethiopian Institute of Agricultural Research (EIAR) and involving more than 2,000 Ethiopian wheat farmers, the study shows that farmers need access to a range of genetically diverse wheat varieties whose resistance is based on multiple genes.

After a severe outbreak in 2010-11 of a previously unseen stripe rust strain, 40 percent of the affected farm households quickly replaced popular but susceptible wheat varieties, according to Moti Jaleta, agricultural economist at CIMMYT and co-author of the publication.

“That epidemic hit about 600,000 hectares of wheat—30 percent of Ethiopia’s wheat lands—and farmers said it cut their yields in half,” Jaleta said. “In general, the rapid appearance and mutation of wheat rust races in Ethiopia has convinced farmers about the need to adopt newer, resistant varieties.”

The fourth most widely grown cereal after tef, maize, and sorghum, wheat in Ethiopia is produced largely by smallholder farmers under rainfed conditions. Wheat production and area under cultivation have increased significantly in the last decade and Ethiopia is among Africa’s top three wheat producers, but the country still imports on average 1.4 million tons of wheat per year to meet domestic demand.

National and international organizations such as EIAR, CIMMYT, and the International Centre for Agricultural Research in the Dry Areas (ICARDA) are working intensely to identify and incorporate new sources of disease resistance into improved wheat varieties and to support the multiplication of more seed to meet farmer demand.

New wheat varieties have provided bigger harvests and incomes for Ethiopia farmers in the last decade, but swiftly mutating and spreading disease strains are endangering wheat’s future, according to Dave Hodson, CIMMYT expert in geographic information and decision support systems, co-author of the new study.

Ethiopian wheat farmers like Abebe Abora, of Doyogena, have benefitted from adopting high-yielding wheat varieties but face threats from fast mutating races of wheat rust disease pathogens. Photo: CIMMYT/Apollo Habtamu.

Ethiopian wheat farmers like Abebe Abora, of Doyogena, have benefitted from adopting high-yielding wheat varieties but face threats from fast mutating races of wheat rust disease pathogens. Photo: CIMMYT/Apollo Habtamu.

“In addition to stripe rust, highly-virulent new races of stem rust are ruining wheat harvests in eastern Africa,” he explained. “These include the deadly Ug99 race group, which has spread beyond the region, and, more recently, the stem rust race TKTTF.”

As an example, he mentioned the case of the wheat variety Digalu, which is resistant to stripe rust and was quickly adopted by farmers after the 2010-11 epidemic. But Digalu has recently shown susceptibility to TKTTF stem rust and must now be replaced.

“In rust-prone Ethiopia, the risks of over-reliance on a widely-sown variety that is protected by a single, major resistance gene—Digalu, for example—are clearly apparent,” he added. “CIMMYT and partners are working hard to replace it with a new variety whose resistance is genetically more complex and durable.”

Hodson said as well that continuous monitoring of the rust populations in Ethiopia and the surrounding region is essential to detect and respond to emerging threats, as well as to ensure that the key pathogen races are used to screen for resistance in wheat breeding programs.

Hodson and partners at the John Innes Centre, UK, and EIAR are leading development of a handheld tool that allows rapid identification of disease strains in the field, instead of having to send them to a laboratory and lose precious time awaiting the results.

CIMMYT and partners are also applying molecular tools to study wheat varietal use in Ethiopia. “There are indications that yields reported by farmers were much lower than official statistics, and farmer recollections of varietal names and other information are not always exact,” Hodson explained. “We are analyzing results now of a follow-up study that uses DNA fingerprinting to better document varietal use and turnover.”

The authors would like to acknowledge the Standing Panel for Impact Assessment (SPIA) for financing, the Diffusion and Impacts of Improved Varieties in Africa (DIIVA) project that supported the first survey in 2011, and Cornell Universitythe Bill & Melinda Gates Foundation, and United Kingdom’s Department for International Development (DFID) through the Durable Rust Resistance in Wheat (DRRW, now called Delivering Genetic Gain in Wheat) project for support for the second survey in 2014.

Young women scientists who will galvanize global wheat research

By Laura Strugnell and Mike Listman

Winners of the Jeanie Borlaug Laube Women in Triticum (WIT) Early Career Award pose in front of the statue of the late Nobel Peace laureate, Dr. Norman E. Borlaug. Included in the photo are Amor Yahyaoui, CIMMYT wheat training coordinator (far left), Jeanie Borlaug Laube (center, blue blouse), and Maricelis Acevedo, Associate Director for Science, the Delivering Genetic Gain in Wheat Project (to the right of Jeanie Borlaug Laube). Photo: CIMMYT/Mike Listman

CIUDAD OBREGÓN, Mexico (CIMMYT) – As more than 200 wheat science and food specialists from 34 countries gathered in northwestern Mexico to address threats to global nutrition and food security, 9 outstanding young women wheat scientists among them showed that this effort will be strengthened by diversity.

Winners of the Jeanie Borlaug Laube Women in Triticum (WIT) Early Career Award joined an on-going wheat research training course organized by the International Maize and Wheat Improvement Center (CIMMYT), 21-23 March.

“As my father used to say, you are the future,” said Jeanie Borlaug Laube, daughter of the late Nobel Peace Prize laureate, Dr. Norman E. Borlaug, and mentor of many young agricultural scientists. Speaking to the WIT recipients, she said, “You are ahead of the game compared to other scientists your age.”

Established in 2010 as part of the Delivering Genetic Gain in Wheat (DGGW) project led by Cornell University, the WIT program has provided professional development opportunities for 44 young women researchers in wheat from more than 20 countries.

The award is given annually to as many as five early science-career women, ranging from advanced undergraduates to recent doctoral graduates and postdoctoral fellows. Selection is based on a scientific abstract and statement of intent, along with evidence of commitment to agricultural development and leadership potential.

Women who will change their professions and the world

Weizhen Liu. Photo: WIT files

Weizhen Liu, a 2017 WIT recipient and postdoctoral researcher at Cornell University, is applying genome-wide association mapping and DNA marker technology to enhance genetic resistance in tetraploid and bread wheat to stripe rust, a major global disease of wheat that is quickly spreading and becoming more virulent.

“I am eager to join and devote myself to improving wheat yields by fighting wheat rusts,” said Liu, who received her bachelors in biotechnology from Nanjing Agricultural University, China, in 2011, and a doctorate from Washington State University in 2016. “Through WIT, I can share my research with other scientists, receive professional feedback, and build international collaboration.”

Mitaly Bansal, a 2016 WIT award winner, currently works as a Research Associate at Punjab Agricultural University, India. She did her PhD research in a collaborative project involving Punjab Agricultural University and the John Innes Centre, UK, to deploy stripe and leaf rust resistance genes from non-progenitor wild wheat in commercial cultivars.

Mitaly Bansal. Photo: WIT files

“I would like to work someday in a position of public policy in India,” said Bansal, who received the Monsanto Beachell-Borlaug scholarship in 2013. “That is where I could have the influence to change things that needed changing.”

Networking in the cradle of wheat’s “Green Revolution”

In addition to joining CIMMYT training for a week, WIT recipients will attend the annual Borlaug Global Rust Initiative (BGRI) technical workshop, to be held this year in Marrakech, Morocco, from 14 to 17 April, and where the 2018 WIT winners will be announced.

The CIMMYT training sessions took place at the Norman Borlaug Experiment Station (CENEB), an irrigated desert location in Sonora State, northwestern Mexico, and coincided with CIMMYT’s 2018 “Visitors’ Week,” which took place from 19 to 23 March.

An annual gathering organized by the CIMMYT global wheat program at CENEB, Visitors’ Week typically draws hundreds of experts from the worldwide wheat research and development community. Participants share innovations and news on critical issues, such as the rising threat of the rust diseases or changing climates in key wheat farmlands.

Through her interaction with Visitors’ Week peers, Liu said she was impressed by the extensive partnering among experts from so many countries. “I realized that one of the most important things to fight world hunger is collaboration; no one can solve food insecurity, malnutrition, and climate change issues all by himself.”

A strong proponent and practitioner of collaboration, Norman E. Borlaug worked with Sonora farmers in the 1940-50s as part of a joint Rockefeller Foundation-Mexican government program that, among other outputs, generated high-yielding, disease-resistant wheat varieties. After bringing wheat self-sufficiency to Mexico, the varieties were adopted in South Asia and beyond in the 1960-70s, dramatically boosting yields and allowing famine-prone countries to feed their rapidly-expanding populations.

This became known as the Green Revolution and, in 1970, Borlaug received the Nobel Peace Prize in recognition of his contributions. Borlaug subsequently led CIMMYT wheat research until his retirement in 1979 and served afterwards as a special consultant to the Center.

When a new, highly virulent race of wheat stem rust, Ug99, emerged in eastern Africa in the early 2000s, Borlaug sounded the alarm and championed a global response that grew into the BGRI and associated initiatives such as DGGW.

“This is just a beginning for you, but it doesn’t end here,” said Maricelis Acevedo, a former WIT recipient who went on to become the leader of DGGW. Speaking during the training course, she observed that many WIT awardees come from settings where women often lack access to higher education or the freedom to pursue a career.

“Through WIT activities, including training courses like this and events such as Visitors’ Week and the BGRI workshop,” Acevedo added, “you’ll gain essential knowledge and skills but you’ll also learn leadership and the personal confidence to speak out, as well as the ability to interact one-on-one with leaders in your field and to ask the right questions.”

CIMMYT is the global leader in publicly-funded maize and wheat research and related farming systems. Headquartered near Mexico City, CIMMYT works with hundreds of partners throughout the developing world to sustainably increase the productivity of maize and wheat cropping systems, thus improving global food security and reducing poverty. CIMMYT is a member of the CGIAR System and leads the CGIAR Research Programs on Maize and Wheat and the Excellence in Breeding Platform. The Center receives generous support from national governments, foundations, development banks and other public and private agencies.

Funded by the Bill & Melinda Gates Foundation and the UK’s Department for International Development (DFID) under UK aid, the DGGW project aims to strengthen the delivery pipeline for new, disease resistant, climate-resilient wheat varieties and to increase the yields of smallholder wheat farmers.

 

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.

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.