Wheat blast is an important disease for warm and humid wheat production regions, caused by Magnaporthe oryzae pathotype Triticum.
The disease was first identified in the state of Paraná of Brazil in 1985, and it subsequently spread to other major wheat-producing areas of Brazil as well as several neighboring countries like Argentina, Bolivia and Paraguay. In recent years, wheat blast has been observed in Bangladesh and Zambia, threatening wheat production in Asia and Africa.
Field resistance source is mostly limited to 2NS carriers, which are being eroded by newly emerged MoT isolates, necessitating an urgent need for broadening the genetic basis of wheat blast resistance.
The changing climate (global warming and irregular rains) and the evolving tendency of the pathogen (increasing virulence, fungicide resistance and sexual recombination) can further aggravate disease incidence and severity.
CIMMYT is working on different strategies to mitigate the global threat of wheat blast, in collaboration with national agricultural research partners in Africa, Asia and Latin America.
Wheat blast damages wheat spikes. (Photo: Xinyao He / CIMMYT)
In an article published in Nature Scientific Reports, a team of scientists led by wheat breeder Philomin Juliana from the International Wheat and Maize Improvement Center (CIMMYT) conducted a large genome-wide association study to look for genomic regions that could also be associated with resistance to wheat blast.
Juliana and fellow scientists found 36 significant markers on chromosome 2AS, 3BL, 4AL and 7BL that appeared to be consistently associated with blast resistance across different environments. Among these, 20 markers were found to be in the position of the 2NS translocation, a chromosomal segment transferred to wheat from a wild relative, Aegilops ventricosa, that has very strong and effective resistance to wheat blast.
The team also gained excellent insights into the blast resistance of the globally-distributed CIMMYT germplasm by genomic fingerprinting a panel over 4,000 wheat lines for the presence of the 2NS translocation, and found that it was present in 94.1% of lines from International Bread Wheat Screening Nurseries (IBWSNs) and 93.7% of lines from Semi-Arid Wheat Screening Nurseries (SAWSNs). Although it is reassuring that such a high percentage of CIMMYT wheat lines already have the 2NS translocation and implied blast resistance, finding other novel resistance genes will be instrumental in building widespread, global resilience to wheat blast outbreaks in the long-term.
The researchers used data collected over the last two years from CIMMYT’s IBWSNs and SAWSNs by collaborators at the Bangladesh Wheat and Maize Research Institute (BWMRI) and Bolivia’s Instituto Nacional de Innovación Agropecuaria y Forestal (INIAF).
Devastating fungal disease
Wheat blast, caused by the fungus Magnaporthe oryzae pathotype Triticum, was first identified in 1985 in South America, but has been seen in Bangladesh in recent years. The expansion of the disease is a great concern for regions of similar environmental conditions in South Asia, and other regions globally.
Although management of the disease using fungicide is possible, it is not completely effective for multiple reasons, including inefficiency during high disease pressure, resistance of the fungal populations to some classes of fungicides, and the affordability of fungicide to resource-poor farmers. Scientists see the development and deployment of wheat with genetic resistance to blast as the most sustainable and farmer-friendly approach to preventing devastating outbreaks around the world.
This work was made possible by the generous support of the Delivering Genetic Gains in Wheat (DGGW) project funded by the Bill & Melinda Gates Foundation, the U.K. Foreign, Commonwealth & Development Office (FCDO) and managed by Cornell University, the U.S. Agency for International Development’s Feed the Future initiative, the CGIAR Research Program on Wheat (WHEAT), the Indian Council of Agricultural Research (ICAR), The Swedish Research Council (Vetenskapsråd), and the Australian Centre for International Agricultural Research (ACIAR).
Wheat blast, a fast-acting and devastating fungal disease, has been reported for the first time on the African continent. In an article published in the scientific journal PLoS One, a team of scientists confirmed that symptoms of wheat blast first appeared in Zambia during the 2018 rainy season, in experimental plots and small-scale farms in the Mpika district, Muchinga province.
Researchers from the International Maize and Wheat Improvement Center (CIMMYT), the US Department of Agriculture – Foreign Disease Weed Science Research Unit (USDA-ARS) and the Zambian Agricultural Research Institute (ZARI) participated in this study.
Wheat blast poses a serious threat to rain-fed wheat production in Zambia and raises the alarm for surrounding regions and countries on the African continent with similar environmental conditions. Worldwide, 2.5 billion consumers depend on wheat as a staple food and, in recent years, several African countries have been actively working towards reducing dependence on wheat imports.
“This presents yet another challenging biotic constraint to rain-fed wheat production in Zambia,” said Batiseba Tembo, wheat breeder at ZARI and lead scientist on the study.
A difficult diagnosis
Researchers from ZARI check for wheat blast in experimental plots. (Photo: Batiseba Tembo/ZARI)
“The first occurrence of the disease was very distressing. This happened at the spike stage, and caused significant losses,” Tembo said. “Nothing of this nature has happened before in Zambia.”
Researchers were initially confused when symptoms of the disease were first reported in the fields of Mpika. Zambia has unique agro-climatic conditions, particularly in the rainfed wheat production system, and diseases such as spot blotch and Fusarium head blight are common.
“The crop had silvery white spikes and a green canopy, resulting in shriveled grains or no grains at all… Within the span of seven days, a whole field can be attacked,” Tembo explained. Samples were collected and analyzed in the ZARI laboratory, and suspicions grew among researchers that this may be a new disease entirely.
Tembo participated in the Basic Wheat Improvement Course at CIMMYT’s global headquarters in Mexico, where she discussed the new disease with Pawan Singh, head of Wheat Pathology at CIMMYT. Singh worked with Tembo to provide guidance and the molecular markers needed for the sample analysis in Zambia, and coordinated the analysis of the wheat disease samples at the USDA-ARS facility in Fort Detrick, Maryland, United States.
All experiments confirmed the presence of the fungus Magnaporthe oryzae pathotype Triticum (MoT), which causes the disease.
“This is a disaster which needs immediate attention,” Tembo said. “Otherwise, wheat blast has the potential to marginalize the growth of rain-fed wheat production in Zambia and may threaten wheat production in neighboring countries as well.”
Wheat blast spreads through infected seeds and crop residues, as well as by spores that can travel long distances in the air. The spread of blast within Zambia is indicated by both mechanisms of expansion.
Wheat blast has expanded rapidly since it was initially discovered in Brazil in 1985. (Map: Kai Sonder/CIMMYT)
A cause for innovation and collaboration
CIMMYT and the CGIAR Research Program on Wheat (WHEAT) are taking action on several fronts to combat wheat blast. Trainings and international courses invite participants to gain new technical skills and knowledge in blast diagnostics, treatment and mitigation strategies. WHEAT scientists and partners are also studying the genetic factors that increase resistance to the disease and developing early warning systems.
“A set of research outcomes, including the development of resistant varieties, identification of effective fungicides, agronomic measures, and new findings in the epidemiology of disease development will be helpful in mitigating wheat blast in Zambia,” Singh said.
“It is imperative that the regional and global scientific communities join hands to determine effective measures to halt further spread of this worrisome disease in Zambia and beyond,” Tembo expressed.
Financial support for this research was provided by the Zambia Agriculture Research Institute (ZARI), the CGIAR Research Program on Wheat (WHEAT), the Australian Centre for International Agricultural Research (ACIAR), and the US Department of Agriculture’s Agricultural Research Service (USDA-ARS).
The Basic Wheat Training Program and Wheat Blast Training is made possible by support from investors including the Australian Centre for International Agricultural Research (ACIAR), WHEAT, the Indian Council of Agricultural Research (ICAR), Krishi Gobeshona Foundation (KGF), the Swedish Research Council (SRC) and the United States Agency for International Development (USAID).
The Accelerating Genetic Gains in Maize and Wheat (AGG) project is funded by the Bill & Melinda Gates Foundation, the UK Foreign, Commonwealth & Development Office, the United States Agency for International Development and the Foundation for Food and Agricultural Research (FFAR).
About CIMMYT
The International Maize and What Improvement Center (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 programs on Maize and Wheat and the Excellence in Breeding Platform. The Center receives support from national governments, foundations, development banks and other public and private agencies. For more information visit staging.cimmyt.org.
An early warning system set to deliver wheat disease predictions directly to farmers’ phones is being piloted in Bangladesh and Nepal by interdisciplinary researchers.
Experts in crop disease, meteorology and computer science are crunching data from multiple countries to formulate models that anticipate the spread of the wheat rust and blast diseases in order to warn farmers of likely outbreaks, providing time for pre-emptive measures, said Dave Hodson, a principal scientist with the International Maize and Wheat Improvement Center (CIMMYT) coordinating the pilot project.
Around 50,000 smallholder farmers are expected to receive improved disease warnings and appropriate management advisories through the one-year proof-of-concept project, as part of the UK Aid-funded Asia Regional Resilience to a Changing Climate (ARRCC) program.
Early action is critical to prevent crop diseases becoming endemic. The speed at which wind-dispersed fungal wheat diseases are spreading through Asia poses a constant threat to sustainable wheat production of the 130 million tons produced in the region each year.
“Wheat rust and blast are caused by fungal pathogens, and like many fungi, they spread from plant to plant — and field to field — in tiny particles called spores,” said Hodson. “Disease strain mutations can overcome resistant varieties, leaving farmers few choices but to rely on expensive and environmentally-damaging fungicides to prevent crop loss.”
“The early warning system combines climate data and epidemiology models to predict how spores will spread through the air and identifies environmental conditions where healthy crops are at risk of infection. This allows for more targeted and optimal use of fungicides.”
The system was first developed in Ethiopia. It uses weather information from the Met Office, the UK’s national meteorological service, along with field and mobile phone surveillance data and disease spread modeling from the University of Cambridge, to construct and deploy a near real-time early warning system.
CIMMYT consultant Madan Bhatta conducts field surveys using Open Data Kit (ODK) in the mid-hills of Nepal. (Photo: D. Hodson/CIMMYT)
Initial efforts focused on adapting the wheat stripe and stem rust model from Ethiopia to Bangladesh and Nepal have been successful, with field surveillance data appearing to align with the weather-driven disease early warnings, but further analysis is ongoing, said Hodson.
“In the current wheat season we are in the process of comparing our disease forecasting models with on-the-ground survey results in both countries,” the wheat expert said.
“Next season, after getting validation from national partners, we will pilot getting our predictions to farmers through text-based messaging systems.”
CIMMYT’s strong partnerships with governmental extension systems and farmer associations across South Asia are being utilized to develop efficient pathways to get disease predictions to farmers, said Tim Krupnik, a CIMMYT Senior Scientist based in Bangladesh.
“Partnerships are essential. Working with our colleagues, we can validate and test the deployment of model-derived advisories in real-world extension settings,” Krupnik said. “The forecasting and early warning systems are designed to reduce unnecessary fungicide use, advising it only in the case where outbreaks are expected.”
Local partners are also key for data collection to support and develop future epidemiological modelling, the development of advisory graphics and the dissemination of information, he explained.
The second stage of the project concerns the adaptation of the framework and protocols for wheat blast disease to improve existing wheat blast early warning systems already pioneered in Bangladesh.
Example of weekly stripe rust spore deposition forecast in Nepal. Darker colors represent higher predicted number of spores deposited. The early warning system combines weather information from the Met Office with field and mobile phone surveillance data and disease spread modeling from the University of Cambridge. (Graphic: University of Cambridge and Met Office)
Strong scientific partnership champions diversity to achieve common goals
The meteorological-driven wheat disease warning system is an example of effective international scientific partnership contributing to the UN Sustainable Development Goals, said Sarah Millington, a scientific manager at Atmospheric Dispersion and Air Quality Group with the Met Office.
“Diverse expertise from the Met Office, the University of Cambridge and CIMMYT shows how combined fundamental research in epidemiology and meteorology modelling with field-based disease observation can produce a system that boosts smallholder farmers’ resilience to major agricultural challenges,” she said.
The atmospheric dispersion modeling was originally developed in response to the Chernobyl disaster and since then has evolved to be able to model the dispersion and deposition of a range of particles and gases, including biological particles such as wheat rust spores.
“The framework together with the underpinning technologies are transferable to forecast fungal disease in other regions and can be readily adapted for other wind-dispersed pests and disease of major agricultural crops,” said Christopher Gilligan, head of the Epidemiology and Modelling Group at the University of Cambridge.
Fungal wheat diseases are an increasing threat to farmer livelihoods in Asia
Wheat leaf rust can be spotted on a wheat plant of a highly susceptible variety in Nepal. The symptoms of wheat rust are dusty, reddish-orange to reddish-brown fruiting bodies that appear on the leaf surface. These lesions produce numerous spores, which are spread by wind and splashing water. (Photo: D Hodson/CIMMYT)
While there has been a history of wheat rust disease epidemics in South Asia, new emerging strains and changes to climate pose an increased threat to farmers’ livelihoods. The pathogens that cause rust diseases are continually evolving and changing over time, making them difficult to control.
Stripe rust threatens farmers in Afghanistan, India, Nepal and Pakistan, typically in two out of five seasons, with an estimated 43 million hectares of wheat vulnerable. When weather conditions are conducive and susceptible cultivars are grown, farmers can experience losses exceeding 70%.
Populations of stem rust are building at alarming rates and previously unseen scales in neighboring regions. Stem rust spores can spread across regions on the wind; this also amplifies the threat of incursion into South Asia and the ARRCC program’s target countries, underscoring the very real risk that the disease could reemerge within the subcontinent.
The devastating wheat blast disease, originating in the Americas, suddenly appeared in Bangladesh in 2016, causing wheat crop losses as high as 30% on a large area, and continues to threaten South Asia’s vast wheat lands.
In both cases, quick international responses through CIMMYT, the CGIAR research program on Wheat (WHEAT) and the Borlaug Global Rust Initiative have been able to monitor and characterize the diseases and, especially, to develop and deploy resistant wheat varieties.
The UK aid-funded ARRCC program is led by the Met Office and the World Bank and aims to strengthen weather forecasting systems across Asia. The program is delivering new technologies and innovative approaches to help vulnerable communities use weather warnings and forecasts to better prepare for climate-related shocks.
The early warning system uses data gathered from the online Rust Tracker tool, with additional fieldwork support from the Cereal Systems Initiative for South Asia (CSISA), funded by USAID and the Bill & Melinda Gates Foundation, both coordinated by CIMMYT.
Disclaimer: The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official views or position of the International Maize and Wheat Improvement Center (CIMMYT).
Daily life as we know it has grinded to a halt and crop scientists are pondering next steps in face of the global COVID-19 crisis. Hans Braun, Director of the Global Wheat Program at the International Maize and Wheat Improvement Center (CIMMYT) and the CGIAR Research Program on Wheat, joins us for a virtual chat to discuss the need for increased investment in crop disease research as the world risks a food security crisis.
What have you learned from your work on contagious wheat diseases that we can take away during this time?
Wheat epidemics go back to biblical times. Wheat scientists now believe Egypt’s “seven bad years” of harvest referenced in the Bible were due to a stem rust outbreak.
So, we know what happens when we have a crop epidemic: diseases can completely wipe out a harvest. I have seen subsistence farmers stand in front of their swaying, golden wheat fields, but there is not a single grain inside the spikes. All because of wheat blast.
There are a lot of parallel issues that I see with COVID-19.
The epidemiology models for humans which we see now have a lot in common with plant epidemiology. For example, if you take a wheat field sown with a variety which is rust-resistant and then you get a spore which mutates and overcomes the resistance — like COVID-19 overcomes the human immune system — it then takes about two weeks for it to sporulate again and produce millions of these mutated spores. They sporulate once more and then you have billions and trillions of spores — then the wheat fields at the local, national and, in the worst case, regional level are severely damaged and in worst case are going to die.
The problem is that since we cannot quarantine wheat, if the weather is favorable these spores will fly everywhere and — just like with COVID-19 — they don’t need a passport to travel.
Could you elaborate on that? How can wheat diseases go global?
Usually it takes around 5 years, sometimes less, until a mutation in a rust spore can overcome the resistance of a wheat variety. Every so often, we see rust epidemics which cover an entire region. To monitor this movement, the Borlaug Global Rust Initiative of Cornell University and CIMMYT, funded by the Bill & Melinda Gates Foundation and DFID, established a global rust monitoring system that provides live data on spore movements.
For example, if you have a new race of stem rust in Yemen — and in Yemen wheat matures early — and then farmers burn the straw, their action “pushes” the spores up into the air, thus allowing them to enter the jet stream and cover 2,000 to 5,000 kilometers in a short period of time. Spores can also be carried on clothes or shoes by people who walked into an infected wheat field. Take Australia, for example, which has very strict quarantine laws. It is surrounded by sea and still eventually they get the new rust races which fly around or come with travelers. One just cannot prevent it.
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)
Could climate change exacerbate the spreading of crop diseases?
Yes, the climate and its variability have a lot to do with it. For example, in the case of yellow rust, what’s extremely important is the time it takes from sporulation to sporulation. Take a rust spore. It germinates, then it grows, it multiplies and then once it is ready it will disperse and infect wheat plants. From one dispersal to the next it takes about two weeks.
In the last decades, in particular for yellow rust, new races are better adapted to high temperature and are multiplying faster. In a Nature paper, we showed that 30 years ago yellow rust was not present in the Great Plains in the US. Today, it is the most important wheat disease there. So there really is something going on and changing and that’s why we are so concerned about new wheat disease races when they come up.
What could an epidemiologist specialized in human viruses take from this?
Well, I think human epidemiologists know very well what happens in a case like COVID-19. Ordinary citizens now also start to understand what a pandemic is and what its related exponential growth means.
Maybe you should ask what policymakers can learn from COVID-19 in order to prevent plant epidemics. When it comes to epidemics, what applies to humans applies to plants. If there is a new race of a given crop disease, in that moment, the plant does not have a defense mechanism, like humans in the case of COVID-19, because we haven’t developed any immunity. While in developed countries farmers can use chemicals to control plant diseases, resource-poor farmers do not have this option, due to lack to access or if the plant protective has not been registered in their country.
In addition to this, our lines of work share a sense of urgency. If “doomsday” happens, it will be too late to react. At present, with a human pandemic, people are worried about the supply chain from food processing to the supermarket. But if we have an epidemic in plants, then we do not have the supply chain from the field to the food processing industry. And if people have nothing to eat, they will go to the streets and we will see violence. We simply cannot put this aside.
What other lessons can policymakers and other stakeholders take away from the current crisis?
The world needs to learn that we cannot use economics as the basis for disease research. We need to better foresee what could happen.
Let’s take the example of wheat blast, a devastating disease that can destroy the wheat spike and was initially confined to South America. The disease arrived in Bangladesh in 2016 and caused small economic damage, maybe 30,000 tons loss in a small geographic area — a small fraction of the national production but a disaster for the smallholder farmer, who thus would have lost her entire wheat harvest. The disease is now controlled with chemicals. But what if chemical resistance is developed and the disease spreads to the 10 million hectares in the Indo-Gangetic Plains of India and the south of Pakistan. Unlikely? But what if it happens?
Agriculture accounts for 30% of the global GDP and the research money [going to agriculture] in comparison to other areas is small. Globally only 5% of R&D is invested in research for development related to agriculture. Such a discrepancy! A million U.S. dollars invested in wheat blast research goes a long way and if you don’t do it, you risk a disaster.
If there is any flip side to the COVID-19 disaster, it is that hopefully our governments realize that they have to play a much more serious role in many areas, in particular public health and disease control in humans but also in plants.
A Lloyd’s report concluded that a global food crisis could be caused by governments taking isolating actions to protect their own countries in response to a breadbasket failure elsewhere. I’m concerned that as the COVID-19 crisis continues, governments will stop exports as some did during the 2008 food price crisis, and then, even if there is enough food around, the 2008 scenario might happen again and food prices will go through the roof, with disastrous impact on the lives of the poorest.
Cover photo: Hans Braun, Director of the Global Wheat Program at the International Maize and Wheat Improvement Center (CIMMYT), inspects wheat plants in the greenhouses. (Photo: Alfonso Cortés/CIMMYT)
Wheat blast is a fast-acting and devastating fungal disease that threatens food safety and security in tropical areas in South America and South Asia. Directly striking the wheat ear, wheat blast can shrivel and deform the grain in less than a week from the first symptoms, leaving farmers no time to act.
The disease, caused by the fungus Magnaporthe oryzae pathotype triticum (MoT), can spread through infected seeds and survives on crop residues, as well as by spores that can travel long distances in the air.
Magnaporthe oryzae can infect many grasses, including barley, lolium, rice, and wheat, but specific isolates of this pathogen generally infect limited species; that is, wheat isolates infect preferably wheat plants but can use several more cereal and grass species as alternate hosts. The Bangladesh wheat blast isolate is being studied to determine its host range. The Magnaporthe oryzae genome is well-studied but major gaps remain in knowledge about its epidemiology.
The pathogen can infect all aerial wheat plant parts, but maximum damage is done when it infects the wheat ear. It can shrivel and deform the grain in less than a week from first symptoms, leaving farmers no time to act.
Where is wheat blast found?
First officially identified in Brazil in 1985, the disease is widespread in South American wheat fields, affecting as much as 3 million hectares in the early 1990s. It continues to seriously threaten the potential for wheat cropping in the region.
In 2016, wheat blast spread to Bangladesh, which suffered a severe outbreak. It has impacted around 15,000 hectares of land in eight districts, reducing yield on average by as much as 51% in the affected fields.
Wheat-producing countries and presence of wheat blast.
How does blast infect a wheat crop?
Wheat blast spreads through infected seeds, crop residues as well as by spores that can travel long distances in the air.
Blast appears sporadically on wheat and grows well on numerous other plants and crops, so rotations do not control it. The irregular frequency of outbreaks also makes it hard to understand or predict the precise conditions for disease development, or to methodically select resistant wheat lines.
At present blast requires concurrent heat and humidity to develop and is confined to areas with those conditions. However, crop fungi are known to mutate and adapt to new conditions, which should be considered in management efforts.
How can farmers prevent and manage wheat blast?
There are no widely available resistant varieties, and fungicides are expensive and provide only a partial defense. They are also often hard to obtain or use in the regions where blast occurs, and must be applied well before any symptoms appear — a prohibitive expense for many farmers.
The Magnaporthe oryzae fungus is physiologically and genetically complex, so even after more than three decades, scientists do not fully understand how it interacts with wheat or which genes in wheat confer durable resistance.
Researchers from the International Maize and Wheat Improvement Center (CIMMYT) are partnering with national researchers and meteorological agencies on ways to work towards solutions to mitigate the threat of wheat blast and increase the resilience of smallholder farmers in the region. Through the USAID-supported Cereal Systems Initiative for South Asia (CSISA) and Climate Services for Resilient Development (CSRD) projects, CIMMYT and its partners are developing agronomic methods and early warning systems so farmers can prepare for and reduce the impact of wheat blast.
CIMMYT works in a global collaboration to mitigate the threat of wheat blast, funded by the Australian Centre for International Agricultural Research (ACIAR), the CGIAR Research Program on Wheat (WHEAT), the Indian Council of Agricultural Research (ICAR) and the Swedish Research Council (Vetenskapsrådet). Some of the partners who collaborate include the Bangladesh Wheat and Maize Research Institute (BWMRI), Bolivia’s Instituto Nacional de Innovación Agropecuaria y Forestal (INIAF), Kansas State University and the Agricultural Research Service of the US (USDA-ARS).
In 2016, the emergence of wheat blast, a devastating seed- and wind-borne pathogen, threatened an already precarious food security situation in Bangladesh and South Asia.
In a bid to limit the disease’s impact in the region, the Bangladesh Agricultural Research Institute (BARI) collaborated with the International Maize and Wheat Improvement Center (CIMMYT) and researchers from nearly a dozen institutions worldwide to quickly develop a long-term, sustainable solution.
The result is BARI Gom 33, a new blast-resistant, high-yielding, zinc-fortified wheat variety, which Bangladesh’s national seed board approved for dissemination in 2017. In the 2017-18 season, the Bangladesh Wheat Research Council provided seed for multiplication and the country’s Department of Agricultural Extension established on-farm demonstrations in blast prone districts.
However, the process of providing improved seed for all farmers can be a long one. In a normal release scenario, it can take up to five years for a new wheat variety to reach those who need it, as nucleus and breeder seeds are produced, multiplied and certified before being disseminated by extension agencies. Given the severity of the threat to farmer productivity and the economic and nutritional benefits of the seed, scientists at CIMMYT argue that additional funding should be secured to expedite this process.
According a new study on the economic benefits of BARI Gom 33, 58 percent of Bangladesh’s wheat growing areas are vulnerable to wheat blast. The rapid dissemination of seed can help resource-poor farmers better cope with emerging threats and changing agro-climatic conditions, and would play a significant role in combatting malnutrition through its increased zinc content. It could also have a positive effect on neighboring countries such as India, which is alarmingly vulnerable to wheat blast.
“Our simulation exercise shows that the benefits of disseminating BARI Gom 33 far exceed the seed multiplication and dissemination costs, which are estimated at around $800 per hectare,” explains Khondoker Mottaleb, CIMMYT socioeconomist and lead author of the study. Even in areas unaffected by wheat blast, scaling out BARI Gom 33 could generate a net gain of $8 million for farmers due to its 5 percent higher average yield than other available varieties. These benefits would nearly double in the case of an outbreak in blast-affected or blast-vulnerable districts.
More than 50 percent of Bangladesh’s wheat growing areas are vulnerable to wheat blast. (Source: Mottaleb et al.)
Based on these findings, the authors urge international development organizations and donor agencies to continue their support for BARI Gom 33, particularly for government efforts to promote the blast-resistant variety. The minimum seed requirement to begin the adoption and diffusion process in the 2019-20 wheat season will be 160 metric tons, which will require an initial investment of nearly $1 million for seed multiplication.
This study was supported by the CGIAR Research Program on wheat agri-food systems (CRP WHEAT), the Australian Centre for International Agricultural Research (ACIAR), the CGIAR Research Program on Agriculture for Nutrition and Health (CRP-A4NH), and the HarvestPlus challenge program (partly funded by the Bill and Melinda Gates Foundation).
Wheat blast is a fast-acting and devastating fungal disease that threatens food safety and security in the Americas and South Asia.
First officially identified in Brazil in 1984, the disease is widespread in South American wheat fields, affecting as much as 3 million hectares in the early 1990s.
In 2016, it crossed the Atlantic Ocean, and Bangladesh suffered a severe outbreak. Bangladesh released a blast-resistant wheat variety — developed with breeding lines from the International Maize and Wheat Improvement Center (CIMMYT) — in 2017, but the country and region remain extremely vulnerable.
The continued spread of blast in South Asia — where more than 100 million tons of wheat are consumed each year — could be devastating.
Researchers with the CIMMYT-led and USAID-supported Cereal Systems Initiative for South Asia (CSISA) and Climate Services for Resilient Development (CSRD) projects partner with national researchers and meteorological agencies on ways to work towards solutions to mitigate the threat of wheat blast and increase the resilience of smallholder farmers in the region. These include agronomic methods and early warning systems so farmers can prepare for and reduce the impact of wheat blast.
This series of infographics shows how wheat blast spreads, its potential effect on wheat production in South Asia and ways farmers can manage it.
This work is funded by the U.S. Agency for International Development (USAID) and the Bill & Melinda Gates Foundation. CSISA partners include CIMMYT, the International Food Policy Research Institute (IFPRI) and the International Rice Research Institute (IRRI).
This blast-infected wheat spike contains no grain, only chaff. Photo: CIMMYT files.
A spatial mapping and ex ante studyregarding the risk and potential spread in South Asia of wheat blast, a mysterious and deadly disease from the Americas that unexpectedly infected wheat in southwestern Bangladesh in 2016, identified 7 million hectares of wheat cropping areas in Bangladesh, India, and Pakistan whose agro-climatic conditions resemble those of the Bangladesh outbreak zone.
The study shows that, under a conservative scenario of 5-10% wheat blast production damage in a single season in those areas, wheat grain losses would amount to from 0.89 to 1.77 million tons worth, between $180 and $350 million. This would strain the region’s already fragile food security and forcing up wheat imports and prices, according to Khondoker Abdul Mottaleb, first author of the study.
“Climate change and related changes in weather patterns, together with continuing globalization, expose wheat crops to increased risks from pathogens that are sometimes transported over long distances,” said Mottaleb.
Foresight research at the International Maize and Wheat Improvement Center (CIMMYT) has focused on new diseases and pests that have emerged or spread in recent decades, threatening global food safety and security. For wheat these include Ug99 and other new strains of stem rust, the movement of stripe rust into new areas, and the sudden appearance in Bangladesh of wheat blast, which had previously been limited to South America.
“As early as 2011, CIMMYT researchers had warned that wheat blast could spread to new areas, including South Asia,” said Kai Sonder, who manages CIMMYT’s geographic information systems lab and was a co-author on the current study, referring to a 2011 notepublished by the American Pathological Society. “Now that forecast has come true.”
CIMMYT has played a pivotal role in global efforts to study and control blast, with funding from the Australian Center for International Agricultural Research (ACIAR), the CGIAR Research Program on Wheat (WHEAT), the Indian Council of Agriculture Research (ICAR), and the United States Agency for International Development (USAID).
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Researchers take part in Wheat Blast screening and surveillance course in Bangladesh. (Photo: CIMMYT/Tim Krupnik)
Fourteen young wheat researchers from South Asia recently attended a screening and surveillance course to address wheat blast, the mysterious and deadly disease whose surprise 2016 outbreak in southwestern Bangladesh devastated that region’s wheat crop, diminished farmers’ food security and livelihoods, and augured blast’s inexorable spread in South Asia.
Held from 24 February to 4 March 2018 at the Regional Agricultural Research Station (RARS), Jessore, as part of that facility’s precision phenotyping platform to develop resistant wheat varieties, the course emphasized hands-on practice for crucial and challenging aspects of disease control and resistance breeding, including scoring infections on plants and achieving optimal development of the disease on experimental wheat plots.
Cutting-edge approaches tested for the first time in South Asia included use of smartphone-attachable field microscopes together with artificial intelligence processing of images, allowing researchers identify blast lesions not visible to the naked eye.
Workshop participants learned how to use the latest in technology to identify and keep track of the deadly Wheat Blast disease. Photo: CIMMYT archives.
“A disease like wheat blast, which respects no borders, can only be addressed through international collaboration and strengthening South Asia’s human and institutional capacities,” said Hans-Joachim Braun, director of the global wheat program of the International Maize and Wheat Improvement Center (CIMMYT), addressing participants and guests at the course opening ceremony. “Stable funding from CGIAR enabled CIMMYT and partners to react quickly to the 2016 outbreak, screening breeding lines in Bolivia and working with USDA-ARS, Fort Detrick, USA to identify resistance sources, resulting in the rapid release in 2017 of BARI Gom 33, Bangladesh’s first-ever blast resistant and zinc enriched wheat variety.”
Cooler and dryer weather during the 2017-18 wheat season has limited the incidence and severity of blast on Bangladesh’s latest wheat crop, but the disease remains a major threat for the country and its neighbors, according to P.K. Malaker, Chief Scientific Officer, Wheat Research Centre (WRC) of the Bangladesh Agricultural Research Institute (BARI).
“We need to raise awareness of the danger and the need for effective management, through training courses, workshops, and mass media campaigns,” said Malaker, speaking during the course.
The course was organized by CIMMYT, a Mexico-based organization that has collaborated with Bangladeshi research organizations for decades, with support from the Australian Center for International Agricultural Research (ACIAR), Indian Council of Agricultural Research (ICAR), CGIAR Research Program on Wheat (WHEAT), the United States Agency for International Development (USAID), and the Bangladesh Wheat and Maize Research Institute (BWMRI).
Speaking at the closing ceremony, N.C.D. Barma, WRC Director, thanked the participants and the management team and distributed certificates. “The training was very effective. BMWRI and CIMMYT have to work together to mitigate the threat of wheat blast in Bangladesh.”
