Wheat spikes damaged by blast. Photo: Xinyao He, CIMMYT
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.
In an article published in Nature Scientific Reports, a team of scientists from the International Maize and Wheat Improvement Center (CIMMYT) and partners, led by CIMMYT associate scientist Philomin Juliana, conducted a large genome-wide association study to look for genomic regions that could also be associated with resistance to wheat blast.
Using data collected over the last two years on CIMMYT’s International Bread Wheat Screening Nurseries (IBWSNs) and Semi-Arid Wheat Screening Nurseries (SAWSNs) by collaborators at the Bangladesh Wheat and Maize Research Institute (BWMRI) and the Instituto Nacional de Innovación Agropecuaria y Forestal (INIAF) in Bolivia, Philomin 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 4000 wheat lines for the presence of the 2NS translocation, and found that it was present in 94.1% of lines from IBWSN and 93.7% of lines from SAWSN. 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.
Read the publication by Philomin Juliana, Xinyao He, Muhammad R. Kabir, Krishna K. Roy, Md. Babul Anwar, Felix Marza, Jesse Poland, Sandesh Shrestha, Ravi P. Singh, and Pawan K. Singh
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), #CIM/2016/219.
Wheat blast in experimental plots (Photo: Batiseba Tembo, ZARI)
Wheat blast, a fast-acting and devastating fungal disease, has been reported for the first time on the African continent, according to a new article published by scientists from the Zambian Agricultural Research Institute (ZARI), the International Maize and Wheat Improvement Center (CIMMYT) and the US Department of Agriculture – Foreign Disease Weed Science Research Unit (USDA-ARS) in the scientific journal PLoS One.
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.
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
“The first occurrence of the disease was very distressing. This happened at the spike stage, and caused significant losses,” said Tembo. “Nothing of this nature has happened before in Zambia.”
Researchers were initially confused when symptoms of the disease in the Mpika fields were first reported. 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 7 days, a whole field can be attacked,” said Tembo. Samples were collected and analyzed in the ZARI laboratory, and suspicions grew among researchers that this may be a new disease entirely.
Wheat blast in a farmer’s field in Mpika district, 2020 (Photo: Batiseba Tembo, ZARI)
A history of devastation
Wheat blast, caused by Magnaporthe oryzae pathotype Triticum (MoT), was initially discovered in Brazil in 1985, and within decades had affected around 3 million hectares of wheat in South America alone. The disease made its first intercontinental jump to Asia in 2016, causing a severe outbreak in Bangladesh, reducing yield on average by as much as 51% in the affected fields.
The disease has now become endemic to Bangladesh, and has potential to expand to similar warm, humid and wet environments in nearby India and Pakistan, as well as other regions of favorable disease conditions.
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.
Developing expert opinions
Tembo participated in the Basic Wheat Improvement Course at CIMMYT 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.
All experiments confirmed the presence of Magnaporthe oryzae pathotype Triticum (MoT).
“This is a disaster which needs immediate attention,” said Tembo. “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 observed in Mpika, Zambia (Photo: Batiseba Tembo, ZARI)
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, such as an international course led by the Bangladesh Wheat and Maize Research Institute (BWMRI) in collaboration with CIMMYT, WHEAT and others, invite international participants to gain new technical skills in blast diagnostics and treatment and understand different strategies being developed to mitigate the wheat blast threat. WHEAT scientists and partners are also working quickly to study genetic factors that increase resistance to the disease and develop early warning systems, among other research interventions.
“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,” said Singh.
Tembo concluded, “It is imperative that the regional and global scientific community join hands to determine effective measures to halt further spread of this worrisome disease in Zambia and beyond.”
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 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).
About Accelerating Genetic Gains in Maize and Wheat for Improved Livelihoods
Accelerating Genetic Gains in Maize and Wheat for Improved Livelihoods (AGG) is a 5-year project that brings together partners in the global science community and in national agricultural research and extension systems to accelerate the development of higher-yielding varieties of maize and wheat — two of the world’s most important staple crops. Funded by the Bill & Melinda Gates Foundation, the UK Foreign, Commonwealth & Development Office (FCDO), the U.S. Agency for International Development (USAID) and the Foundation for Food and Agriculture Research (FFAR), AGG fuses innovative methods that improve breeding efficiency and precision to produce and deliver high-yielding varieties that are climate-resilient, pest- and disease-resistant, highly nutritious, and targeted to farmers’ specific needs.
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 www.cimmyt.org.
Wheat blast is a devastating fungal disease threatening agricultural productivity and food security in the Americas and South Asia. First identified in Brazil in 1984, it spread to Bangladesh in 2016, prompting the government to request scientists for an early warning system.
A new infographic, developed by researchers at the Cereal Systems Initiative for Asia (CSISA) explains how wheat blast is spread and how an early warning system can help extension agents and farmers get ahead of the disease.
Researchers trained as part of global response to the threat of wheat blast.
Participants at the wheat blast training course. Photo: Md. Babul Anwar, BWMRI
The Bangladesh Wheat and Maize Research Institute (BWMRI), in collaboration with the International Maize and Wheat Improvement Center (CIMMYT), recently trained 25 scientists from Bangladesh, India, Nepal, Zambia and Afghanistan on germplasm screening and field surveillance of wheat blast.
The training course took place on March 1-10 at Bangladesh’s Regional Agricultural Research Station in Jashore.
Wheat blast, a fearsome fungal disease first reported in Bangladesh in 2016, is a huge threat to food safety and security in South America and South Asia. Directly striking the wheat spike, wheat blast can shrivel and deform the grain in less than a week from the first symptoms, leaving farmers no time to act.
Participants gain hand-on experience at the wheat blast training course. Photo: Md. Babul Anwar, BWMRI
To mitigate the threat of wheat blast, a Precision Phenotyping Platform (PPP) was established in Jashore in 2018 to screen wheat germplasm for the disease. The platform has been a reliable source of screening for wheat lines around the world and has proven a great success towards taming the wheat blast disease. Currently around 5,000 wheat lines from Bangladesh, China, India, Japan, Mexico, Nepal and Pakistan, are being tested under natural and artificial inoculated conditions.
Participants of the training course gained hands-on experience in disease scoring and evaluation at the facility. Field visits were also arranged to nearby wheat blast hotspots, including wheat blast affected fields in Meherpur, to see how resistant and susceptible cultivars perform under natural epidemic conditions.
“Bangladesh is our neighboring country and wheat blast is a very concerning issue for us. I am very lucky that I have been nominated for this training. Now I am very clear about wheat blast symptoms as well as other confounding diseases in the field,” said Dr. Deepshikha, a wheat pathologist from Govind Ballabh Pant University of Agriculture and Technology (GBPUA&T), Pantnagar, India during the field visit in Meherpur.
Participants also visited Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), in Gazipur where Dr. Tofazzal Islam, Department of Biotechnology Professor, is leading independent wheat blast research activities including mutation breeding and the use of nano technology and probiotic bacteria in controlling wheat blast.
Participants at the wheat blast training course which took place on March 1-10. Photo: Md. Babul Anwar, BWMRI
Since day one, the Government of Bangladesh has been very proactive in combatting wheat blast. Government initiatives include declaring “wheat holidays”—or temporarily banning cultivation in target areas — building awareness, collaborating with international donors and research organizations, and fast tracking the release of resistant varieties.
Despite the progress made in wheat blast monitoring research, scientists are still struggling to figure out the right epidemiological criteria for managing this disease. While disease pressure in Bangladesh has been low in the last three years, wheat blast has been observed in newer districts, signifying the expansion of the pathogen in the country.
Participants at this year’s wheat blast training course. Photo: Md. Babul Anwar, BWMRI
The knowledge gained in the training course will allow participants to refine blast research in their respective countries. They will also be able to raise awareness back home concerning the threat of blast and alert farmers based on the experience Bangladesh has adopted in the last four years.
The training was made possible by support from investors including the Australian Centre for International Agriculture Research (ACIAR), the CGIAR Research Program on WHEAT (CRP 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).
This story by Matthew O’ Leary was originally published on the CIMMYT website.
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.
This article by Matthew O’ Leary was originally posted on the CIMMYT website.
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.
Farmers around the world face constant threats from crop pests and diseases. One such threat is wheat blast, a disease that attacks maturing grains, causing them to shrivel. Fortunately, new advances in technology and modeling are making it easier to identify, prevent and control diseases like this.
Outbreaks of wheat blast in South Asia — a region where people consume over 100 million tons of wheat each year — have a major impact on food security and income. In 2016, a wheat blast outbreak struck South Asia unexpectedly. In Bangladesh alone, 25 to 30 percent of wheat was negatively affected, threatening progress in regional food security. Blast disease has the potential to reduce wheat production by up to 85 million tons in Bangladesh — a projected $13 million loss in farmers’ profits each year when an outbreak occurs.
Luckily, with support from Feed the Future and its partners, there is a reason for hope. A new digital early warning system can help farmers and scientists get ahead. It integrates mathematical models that, when combined with weather forecasts, can simulate disease growth and risks to provide an advanced warning about potential wheat blast outbreaks. With three years of data already recorded, the system — originally piloted in Brazil, where the wheat blast originated in 1985 — is being rolled out across Bangladesh to deliver real-time disease updates to extension workers and smallholder farmers via SMS and voice message.
“Through collaborative research with Professor Jose Mauricio Fernandes, a crop pathologist from Embrapa, and Mr. Felipe de Vargas, a computer scientist with Universidade de Passo Fundo, we have established a model to identify areas at risk of wheat blast infection with five days advanced warning,” said Timothy J. Krupnik, senior scientist and systems agronomist at the International Maize and Wheat Improvement Centre (CIMMYT). “It can provide Bangladesh’s 1.2 million wheat farmers a head start against this disease.”
This data-driven early warning system analyzes environmental conditions for potential disease development in crucial wheat-growing areas of Bangladesh and Brazil. Using this information, the system generates forecast maps and automatic advice for farmers of where and when an outbreak is most likely to strike.
This innovation can also save wheat farmers money. Many apply fungicides on a calendar basis — between two to three times per season — as a preventative measure. This is costly and risks negative environmental effects. Now, the early warning system can push advice to extension agents and farmers, indicating when disease control is really needed.
“Our hope is that it will help reduce unnecessary fungicide use and empower farmers to implement cost-effective and resilient practices to overcome wheat blast risks instead,” Krupnik said.
With wheat as a key crop in Bangladesh, the digital warning system will help prepare farmers to get a head start to reduce the impact of wheat blast with crucial advice from extension agents in areas of need.
An ongoing projectwas praised for its swift progress in the
fight against wheat blast in Bangladesh and South Asia
Eric Huttner, ACIAR Research Program Manager speaking at last month’s mid-term review on wheat blast in Bangladesh and South Asia
At
a mid-term review event last month at the BRAC Learning Centre in Dinajpur,
Bangladesh, professionals from the Bangladesh Ministry of Agriculture, the
Bangladesh Wheat and Maize Research Institute (BWMRI), the Bangladesh
Agriculture Research Institute (BARI), the Department of Agriculture Extension
(DAE), the Krishi Gobeshona Foundation (KGF), the Bangladesh Agriculture
Development Corporation (BADC) and the International Maize and Wheat
Improvement Center (CIMMYT) discussed progress made in the battle against wheat
blast in Bangladesh and South Asia.
Wheat blast is a fast-acting and devastating fungal disease that threatens wheat production and food security in South America and South Asia. The disease, which originated in South America and first appeared in Bangladesh in 2016, can by dispersed by wind across large distances and spores can be seed borne. There is deep concern among scientists that the disease could spread further across South Asia. A 2018 ex-ante analysis found that in Bangladesh, India and Pakistan wheat blast could potentially cause losses of 0.89 – 1.77 million tons each year, with 7 million hectares of growing area at risk.
In 2017, CIMMYT, BWMRI and the Instituto Nacional de Innovación Agropecuaria y Forestal (INIAF) in Bolivia joined forces in an international effort to tackle wheat blast through widespread adoption of blast resistant wheat varieties.
The project, funded by the Australian Centre for International Agricultural Research (ACIAR) addresses wheat blast in Bangladesh and South Asia through the identification of new sources of resistance genes for wheat blast and development of wheat blast resistant varieties. The germplasm, genes and markers, and genetic information developed through the project are shared with South Asian national wheat breeding programs and other researchers, finally ending up in farmers’ fields as resistant varieties.
The
review meeting was chaired by BWMRI Director General Israil Hossain, and
featured remarks by Bangladesh’s Additional Secretary of the Ministry of
Agriculture Kamala Ranjan Das.
“This
project has over-delivered on its milestones,” said Eric Huttner, ACIAR
Research Program Manager and lead of the review. “It’s very likely that the
project will reduce the risk of blast on wheat production in Bangladesh.”
Early
impacts in terms of research capacity and infrastructure are very clear:
The project-established precision phenotyping platform in Jashore
— the first of its kind in Bangladesh and the region — is running at full capacity, screening for
blast in wheat germplasm materials from as far away as China, the United States
and Europe. The facility currently has
the capacity to evaluate almost 5,000 wheat germplasm materials per season and
there are ongoing plans for expansion and improvement.
Sixty-nine researchers and development professionals, including 9 women,
have benefited from the capacity development activities.
Molecular research is also making progress. Pawan Singh, project
leader and head of Wheat Pathology at CIMMYT, noted that the rapid response was
possible due to collective and collaborative action by research partners in
this project and beyond.
Meeting attendees emphasized the urgency and importance of
the project, which is set to conclude in 2021, in the battle against a
fast-moving and devastating disease.
As Huttner told attendees, “Now the resistant or tolerant
materials need to be efficiently deployed for breeding high-performance wheat
varieties that reach stakeholders as early as possible.”
Lead agricultural scientists from G20 member countries gathered
in Tokyo, Japan last month to discuss ways to promote science and technology as
mechanisms to support the global food system.
The Meeting of Agricultural
Chief Scientists (MACS), which took place on April 25-26 in Tokyo, focused
on identifying global research priorities in agriculture and ways to facilitate
collaboration among G20 members and with relevant stakeholders. The purpose is to develop a global agenda ahead
of the May 11-12 meeting of G20 Agricultural Ministers.
CGIAR Research Program on Wheat (WHEAT) Program Manager
Victor Kommerell was among the attendees.
“It is essential to advocate for science-based decision making,” he said. “Better connecting the dots between national agricultural research agendas and the CGIAR international agenda is important. The G20 wheat initiative and WHEAT have made a good start.”
The threat of pests and the importance
of adopting climate smart technology came up as high priorities.
Transboundary pests have become a
serious threat to food security, exacerbated by the globalized movement of
people and commodities and the changing climate. As Kommerell commented to the
attendees, pathogens and pests cause
global crop losses of 20 to 30 percent. This has a “double penalty” effect,
wasting both food and resources invested in farming inputs.
The International Maize and Wheat
Improvement Center (CIMMYT) is particularly focused on pests and diseases
threatening maize and wheat, such as Fall armyworm and wheat rust and blast. Kommerell summarized a number of research-based
solutions underway thanks to international collaboration – including building globally-accessible
rapid screening facilities and using wild crop relatives as a genetic source
for resistance. But non-technical solutions, such as boosting awareness and communicating
preventative farming practices are also important.
The agricultural field is especially vulnerable to the effects of changing climate and weather variability, while at the same time heavily contributing as a source of greenhouse gases. Innovative agricultural technologies and practices are essential for sustainable production, climate resilience and carbon sequestration as well as reducing greenhouse gas emissions.
The key, the attendees concluded in a meeting communiqué, is the open and international exchange of knowledge, experience, and practices. Networks are already in place, but need strengthening at both the regional and international level.
To that end, a task force led by
Australia and the United States will develop guidelines for working groups and
initiatives designed to mitigate pests and scale adoption of climate smart
technologies.
The government of Japan is also taking
an active role, with plans to hold international conferences this year to facilitate
sharing of experiences, research, and best practices from G20 countries.
In an attempt to curb the spread of this disease, policymakers in the region are considering a “wheat holiday” policy: banning wheat cultivation for a few years in targeted areas. Since wheat blast’s Magnaporthe oryzae pathotype triticum (MoT) fungus can survive on seeds for up to 22 months, the idea is to replace wheat with other crops, temporarily, to cause the spores to die. In India, which shares a border of more than 4,000 km with Bangladesh, the West Bengal state government has already instituted a two-year ban on wheat cultivation in two districts, as well as all border areas. In Bangladesh, the government is implementing the policy indirectly by discouraging wheat cultivation in the severely blast affected districts.
CIMMYT researchers recently published in two ex-ante studies to identify economically feasible alternative crops in Bangladesh and the bordering Indian state of West Bengal.
Alternate crops
The first step to ensuring that a ban
does not threaten the food security and livelihoods
of smallholder farmers, the authors assert, is to supply farmers with economically feasible alternative crops.
In Bangladesh, the authors examined the economic
feasibility of seven crops as an alternative to wheat, first in the entire
country, then in 42 districts vulnerable to blast, and finally in ten districts
affected by wheat blast. Considering the cost of
production and revenue per hectare, the study ruled out boro rice, chickpeas
and potatoes as feasible alternatives to wheat due to their negative net
return. In contrast, they found that cultivation of maize, lentils, onions, and
garlic could be profitable.
The study in India looked at ten crops
grown under similar conditions as wheat in the state of West Bengal, examining the
economic viability of each. The authors
conclude that growing maize, lentils, legumes
such aschickpeas and urad bean, rapeseed, mustard and potatoes
in place of wheat appears to be profitable, although they warn that more rigorous research
and data are needed to confirm and support this transition.
Selecting alternative crops is no easy
task. Crops offered to farmers to replace wheat must be appropriate for the
agroecological zone and should not require additional investments for
irrigation, inputs or storage facilities. Also,
the extra production of labor-intensive and export-oriented crops, such as
maize in India and potatoes in Bangladesh, may add costs or require new markets
for export.
There is also the added worry that the MoT fungus could survive on one of these
alternative crops, thus completely negating any benefit of the “wheat holiday.”
The authors point out that the fungus has been reported to survive on maize.
A short-term solution?
In both studies, the authors discourage a
“wheat holiday” policy as a holistic solution. However, they leave room for
governments to pursue it on an interim and short-term basis.
In the case of Bangladesh, the researchers assert that a “wheat holiday” would increase the country’s reliance on imports, especially in the face of rapidly increasing wheat demand and urbanization. A policy that results in complete dependence on wheat imports, they point out, may not be politically attractive or feasible. Also, the policy would be logistically challenging to implement. Finally, since the disease can potentially survive on other host plants, such as weeds and maize—it may not even work in the long run.
In the interim, the government of
Bangladesh may still need to rely on the “wheat holiday” policy in the severely
blast-affected districts. In these areas, they should encourage farmers to
cultivate lentils, onions and garlic. In addition,
in the short term, the government should make generic fungicides widely
available at affordable prices and provide an early warning
system as well as adequate information to help farmers
effectively combat the disease and minimize its consequences.
In the case of West Bengal, India, similar
implications apply – although the authors conclude that the “wheat holiday”
policy could only work if Bangladesh has the same policy in its blast-affected
border districts, which would involve potentially difficult and costly
inter-country collaboration, coordination and logistics.
Actions for long-term success
The CIMMYT researchers urge the governments
of India and Bangladesh, their counterparts in the region and international
stakeholders to pursue long-term solutions, including developing a convenient
diagnostic tool for wheat blast surveillance and a platform for open data and
science to combat the fungus.
A promising development is the blast-resistant (and zinc-enriched) wheat variety BARI Gom 33 which the Bangladesh Agricultural Research Institute (BARI) released in 2017 with support from CIMMYT.However, it will take at least three to five years before it will be available to farmers throughout Bangladesh. The authors urged international donor agencies to speed up the multiplication process of this variety.
CIMMYT scientists in both studies close
with an urgent plea for international financial and technical support for collaborative
research on disease epidemiology and forecasting, and the development and
dissemination of new wheat blast-tolerant and resistant varieties and
complementary management practices – crucial steps to ensuring food security for
more than a billion people in South Asia.
First officially reported in Brazil in 1985, where it eventually spread to 3 million hectares in South America and became the primary reason for limited wheat production in the region, wheat blast moved to Bangladesh in 2016. There it affected nearly 15,000 hectares of land in eight districts, reducing yield by as much as 51 percent in the affected fields.
Blast is devilish: directly striking the wheat ear, it can shrivel and deform the grain in less than a week from the first symptoms, leaving farmers no time to act. There are no widely available resistant varieties, and fungicides are expensive and provide only a partial defense. The disease, caused by the fungus Magnaporthe oryzae pathotype triticum (MoT), can spread through infected seeds as well as by spores that can travel long distances in the air.
South Asia has a long tradition of wheat consumption, especially in northwest India and Pakistan, and demand has been increasing rapidly across South Asia. It is the second major staple in Bangladesh and India and the principal staple food in Pakistan. Research indicates 17 percent of wheat area in Bangladesh, India, and Pakistan — representing nearly 7 million hectares – is vulnerable to the disease, threatening the food security of more than a billion people.
