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.
Researchers and experts from 15 countries convened in Zambia, between 4-15 March 2024, for an international training on wheat blast disease screening, surveillance, and management.
Wheat blast, caused by pathogen Magnaporthe oryzae pathotype triticum, is threatening global wheat production especially in warmer and humid regions. The disease was first observed in Parana state of Brazil in 1985 and subsequently spread to Bolivia, Paraguay, and Argentina. Outside of South America, wheat blast incidences were recorded for the first time in Bangladesh in 2016 and in Zambian wheat fields in 2018.
To mitigate the impact of this potential plant pandemic, the Zambia Agriculture Research Institute (ZARI), in collaboration with CIMMYT and other partners, organized a comprehensive training for building research capacity and raising awareness within the local and international community, especially in at-risk countries.
“This collaborative effort, supported by various international partners and funders, underscores the importance of global cooperation in addressing agricultural challenges such as wheat blast. The objective of the training was to empower researchers with knowledge and tools for enhanced wheat production resilience in regions vulnerable to this destructive disease,” said Pawan Kumar Singh, principal scientist and project leader at CIMMYT. Singh collaborated with Batiseba Tembo, wheat breeder at ZARI-Zambia, to coordinate and lead the training program.
Thirty-eight wheat scientists, researchers, professors, policymakers, and extension agents from countries including Bangladesh, Brazil, Ethiopia, India, Kenya, Mexico, Nepal, South Africa, Sweden, Tanzania, United Kingdom, Uruguay, Zambia, and Zimbabwe convened at the Mt. Makulu Central Research Station in Chilanga, Zambia.
“Wheat blast is a devastating disease that requires concerted efforts to effectively manage it and halt further spread. The disease is new to Africa, so developing capacity amongst country partners before the disease spreads more widely is critical,” said Tembo.
Participants at the International Training on Wheat Blast Screening and Surveillance. (Photo: CIMMYT)
Highlights from the training: discussions, lab exercises, and field visits
During the training, participants engaged in lectures, laboratory exercises, and field visits. There were insightful discussions on key topics including the fundamentals of wheat blast epidemiology, disease identification, molecular detection of the wheat blast pathogen, isolation and preservation techniques for the pathogen, disease scoring methods, disease management strategies, and field surveillance and monitoring.
The course also provided practical experience in disease evaluation at the Precision Phenotyping Platform (PPP) screening nursery located in Chilanga research station. This involved characterization of a diverse range of wheat germplasm with the aim of releasing resistant varieties in countries vulnerable to wheat blast. Additionally, participants undertook field visits to farmers’ fields, conducting surveillance of wheat blast-infected areas. They collected samples and recorded survey data using electronic open data kit (ODK) capture tools.
Participants listen to a lecture by B.N. Verma, director of Zambia Seed Co., on the history of wheat production in Zambia. (Photo: CIMMYT)
“The killer disease needs to be understood and managed utilizing multi-faceted approaches to limit the expansion and damages it can cause to global wheat production. The Bangladesh Wheat and Maize Research Institute (BWMRI) is willing to share all the strategies it deployed to mitigate the effect of wheat blast,” said Golam Faruq, BWMRI’s director general.
Participants visited seed farms to gain practical insights into seed production processes and quality assurance measures. These visits provided first-hand knowledge of seed selection, breeding techniques, and management practices crucial for developing resistant wheat varieties. Participants also visited research sites and laboratories to observe advanced research methodologies and technologies related to wheat blast management. These visits exposed them to cutting-edge techniques in disease diagnosis, molecular analysis, and germplasm screening, enhancing their understanding of effective disease surveillance and control strategies.
Field visit. (Photo: CIMMYT)
“The training and knowledge sharing event was a significant first step in developing understanding and capacity to deal with wheat blast for partners from several African countries. It was wonderful to see the efforts made to ensure gender diversity among participants,” said Professor Diane Saunders from the John Innes Centre, UK.
Climate change poses a threat to yields and food security worldwide, with plant diseases as one of the main risks. An international team of researchers, surrounding professor Senthold Asseng from the Technical University of Munich (TUM), has now shown that further spread of the fungal disease wheat blast could reduce global wheat production by 13% until 2050. The result is dramatic for global food security.
With a global cultivation area of 222 million hectares and a harvest volume of 779 million tons, wheat is an essential food crop. Like all plant species, it is also struggling with diseases that are spreading more rapidly compared to a few years ago because of climate change. One of these is wheat blast. In warm and humid regions, the fungus magnaporthe oryzae has become a serious threat to wheat production since it was first observed in 1985. It initially spread from Brazil to neighboring countries. The first cases outside of South America occurred in Bangladesh in 2016 and in Zambia in 2018. Researchers from Germany, Mexico, Bangladesh, the United States, and Brazil have now modeled for the first time how wheat blast will spread in the future.
Wheat fields affected by wheat blast fungal disease in Passo Fundo, Rio Grande do Sul, Brazil. (Photo: Paulo Ernani Peres Ferreira)
Regionally up to 75% of total wheat acreage affected
According to the researchers, South America, southern Africa, and Asia will be the regions most affected by the future spread of the disease. Up to 75% of the area under wheat cultivation in Africa and South America could be at risk in the future. According to the predictions, wheat blast will also continue to spread in countries that were previously only slightly impacted, including Argentina, Zambia, and Bangladesh. The fungus is also penetrating countries that were previously untouched. These include Uruguay, Central America, the southeastern US, East Africa, India, and eastern Australia. According to the model, the risk is low in Europe and East Asia—with the exception of Italy, southern France, Spain, and the warm and humid regions of southeast China. Conversely, where climate change leads to drier conditions with more frequent periods of heat above 35 °C, the risk of wheat blast may also decrease. However, in these cases, heat stress decreases the yield potential.
Wheat fields affected by wheat blast fungal disease in Passo Fundo, Rio Grande do Sul, Brazil. (Photo: Paulo Ernani Peres Ferreira)
Dramatic yield losses call for adapted management
The affected regions are among the areas most severely impacted by the direct consequences of climate change. Food insecurity is already a significant challenge in these areas and the demand for wheat continues to rise, especially in urban areas. In many regions, farmers will have to switch to more robust crops to avoid crop failures and financial losses. In the midwest of Brazil, for example, wheat is increasingly being replaced by maize. Another important strategy against future yield losses is breeding resistant wheat varieties. CIMMYT in collaboration with NARs partners have released several wheat blast-resistant varieties which have been helpful in mitigating the effect of wheat blast. With the right sowing date, wheat blast-promoting conditions can be avoided during the ear emergence phase. Combined with other measures, this has proven to be successful. In more specific terms, this means avoiding early sowing in central Brazil and late sowing in Bangladesh.
First study on yield losses due to wheat blast
Previous studies on yield changes due to climate change mainly considered the direct effects of climate change such as rising temperatures, changing precipitation patterns, and increased CO2 emissions in the atmosphere. Studies on fungal diseases have so far ignored wheat blast. For their study, the researchers focused on the influence of wheat blast on production by combining a simulation model for wheat growth and yield with a newly developed wheat blast model. Environmental conditions such as the weather are thus included in the calculations, as is data on plant growth. In this way, the scientists are modeling the disease pressure in the particularly sensitive phase when the ear matures. The study focused on the influence of wheat blast on production. Other consequences of climate change could further reduce yields.
One of the world’s largest crop pathogen surveillance systems is set to expand its analytic and knowledge systems capacity to protect wheat productivity in food vulnerable areas of East Africa and South Asia.
Researchers announced the Wheat Disease Early Warning Advisory System (Wheat DEWAS), funded through a $7.3 million grant from the Bill & Melinda Gates Foundation and the United Kingdom’s Foreign, Commonwealth & Development Office, to enhance crop resilience to wheat diseases.
The project is led by David Hodson, principal scientist at CIMMYT, and Maricelis Acevedo, research professor of global development and plant pathology at Cornell University’s College of Agriculture and Life Sciences. This initiative brings together research expertise from 23 research and academic organizations from sub-Saharan Africa, South Asia, Europe, the United States and Mexico.
Wheat DEWAS aims to be an open and scalable system capable of tracking important pathogen strains. The system builds on existing capabilities developed by the research team to provide near-real-time model-based risk forecasts and resulting in accurate, timely and actionable advice to farmers. As plant pathogens continue to evolve and threaten global food production, the system strengthens the capacity of countries to respond in a proactive manner to transboundary wheat diseases.
The system focuses on the two major fungal pathogens of wheat known as rust and blast diseases. Rust diseases, named for a rust-like appearance on infected plants, are hyper-variable and can significantly reduce crop yields when they attack. The fungus releases trillions of spores that can ride wind currents across national borders and continents and spread devastating epidemics quickly over vast areas.
Wheat blast, caused by the fungus Magnaporte oryzae Tritici, is an increasing threat to wheat production, following detection in both Bangladesh and Zambia. The fungus spreads over short distances and through the planting of infected seeds. Grains of infected plants shrivel within a week of first symptoms, providing little time for farmers to take preventative actions. Most wheat grown in the world has limited resistance to wheat blast.
“New wheat pathogen variants are constantly evolving and are spreading rapidly on a global scale,” said Hodson, principal investigator for Wheat DEWAS. “Complete crop losses in some of the most food vulnerable areas of the world are possible under favorable epidemiological conditions. Vigilance coupled with pathogen-informed breeding strategies are essential to prevent wheat disease epidemics. Improved monitoring, early warning and advisory approaches are an important component for safeguarding food supplies.”
Previous long-term investments in rust pathogen surveillance, modelling, and diagnostics built one of the largest operational global surveillance and monitoring system for any crop disease. The research permitted the development of functioning prototypes of advanced early warning advisory systems (EWAS) in East Africa and South Asia. Wheat DEWAS seeks to improve on that foundation to build a scalable, integrated, and sustainable solution that can provide improved advanced timely warning of vulnerability to emerging and migrating wheat diseases.
“The impact of these diseases is greatest on small-scale producers, negatively affecting livelihoods, income, and food security,” Acevedo said. “Ultimately, with this project we aim to maximize opportunities for smallholder farmers to benefit from hyper-local analytic and knowledge systems to protect wheat productivity.”
The system has already proven successful, contributing to prevention of a potential rust outbreak in Ethiopia in 2021. At that time, the early warning and global monitoring detected a new yellow rust strain with high epidemic potential. Risk mapping and real-time early forecasting identified the risk and allowed a timely and effective response by farmers and officials. That growing season ended up being a production record-breaker for Ethiopian wheat farmers.
While wheat is the major focus of the system, pathogens with similar biology and dispersal modes exist for all major crops. Discoveries made in the wheat system could provide essential infrastructure, methods for data collection and analysis to aid interventions that will be relevant to other crops.
India can applaud a hallmark in national food production: in 2023, the harvest of wheat—India’s second most important food crop—will surpass 110 million tons for the first time.
This maintains India as the world’s number-two wheat producer after China, as has been the case since the early 2000s. It also extends the wheat productivity jumpstart that begun in the Green Revolution—the modernization of India’s agriculture during the 1960s-70s that allowed the country to put behind it the recurrent grain shortages and extreme hunger of preceding decades.
“Newer and superior wheat varieties in India continually provide higher yields and genetic resistance to the rusts and other deadly diseases,” said Distinguished Scientist Emeritus at CIMMYT, Ravi Singh. “More than 90 percent of spring bread wheat varieties released in South Asia in the last three decades carry CIMMYT breeding contributions for those or other valued traits, selected directly from the Center’s international yield trials and nurseries or developed locally using CIMMYT parents.”
Wheat grain yield in Indian farmers’ fields rose yearly by more than 1.8 percent—some 54 kilograms per hectare—in the last decade, a remarkable achievement and significantly above the global average of 1.3 percent. New and better wheat varieties also reach farmers much sooner, due to better policies and strategies that speed seed multiplication, along with greater involvement of private seed producers.
“The emergence of Ug99 stem rust disease from eastern Africa in the early 2000s and its ability to overcome the genetic resistance of older varieties drove major global and national initiatives to quickly spread the seed of newer, resistant wheat and to encourage farmers to grow it,” Singh explained. “This both protected their crops and delivered breeding gains for yield and climate resilience.”
CIMMYT has recently adopted an accelerated breeding approach that has reduced the breeding cycle to three years and is expected to fast-track genetic gains in breeding populations and hasten delivery of improvements to farmers. The scheme builds on strong field selection and testing in Mexico, integrates genomic selection, and features expanded yield assays with partner institutions. To stimulate adoption of newer varieties, the Indian Institute of Wheat and Barley Research (IIWBR, of the Indian Council of Agricultural Research, ICAR) operates a seed portal that offers farmers advanced booking for seed of recently released and other wheat varieties.
Private providers constitute another key seed source. In particular, small-scale seed producers linked to the IIWBR/ICAR network have found a profitable business in multiplying and marketing new wheat seed, thus supporting the replacement of older, less productive or disease susceptible varieties.
Farm innovations for changing climates and resource scarcities
Following findings from longstanding CIMMYT and national studies, more Indian wheat farmers are sowing their crops weeks earlier so that the plants mature before the extreme high temperatures that precede the monsoon season, thus ensuring better yields.
New varieties DBW187, DBW303, DBW327, DBW332 and WH1270 can be planted as early as the last half of October, in the northwestern plain zone. Recent research by Indian and CIMMYT scientists has identified well-adapted wheat lines for use in breeding additional varieties for early sowing.
Resource-conserving practices promoted by CIMMYT and partners, such as planting wheat seed directly into the unplowed fields and residues from a preceding rice crop, shave off as much as two weeks of laborious plowing and planking.
Weeds in zero-tillage wheat in India. (Photo: Petr Kosina/CIMMYT)
“This ‘zero tillage’ and other forms of reduced tillage, as well as straw management systems, save the time, labor, irrigation water and fuel needed to plant wheat, which in traditional plowing and sowing requires many tractor passes,” said Arun Joshi, CIMMYT wheat breeder and regional representative for Asia and managing director of the Borlaug Institute for South Asia (BISA). “Also, letting rice residues decompose on the surface, rather than burning them, enriches the soil and reduces seasonal air pollution that harms human health in farm communities and cities such as New Delhi.”
Sustainable practices include precision levelling of farmland for more efficient irrigation and the precise use of nitrogen fertilizer to save money and the environment.
Science and policies ensure future wheat harvests and better nutrition
Joshi mentioned that increased use of combines has sped up wheat harvesting and cut post-harvest grain losses from untimely rains caused by climate change. “Added to this, policies such as guaranteed purchase prices for grain and subsidies for fertilizers have boosted productivity, and recent high market prices for wheat are convincing farmers to invest in their operations and adopt improved practices.”
To safeguard India’s wheat crops from the fearsome disease wheat blast, native to the Americas but which struck Bangladesh’s wheat fields in 2016, CIMMYT and partners from Bangladesh and Bolivia have quickly identified and cross-bred resistance genes into wheat and launched wheat disease monitoring and early warning systems in South Asia.
“More than a dozen wheat blast resistant varieties have been deployed in eastern India to block the disease’s entry and farmers in areas adjoining Bangladesh have temporarily stopped growing wheat,” said Pawan Singh, head of wheat pathology at CIMMYT.
Building on wheat’s use in many Indian foods, under the HarvestPlus program CIMMYT and Indian researchers applied cross-breeding and specialized selection to develop improved wheats featuring grain with enhanced levels of zinc, a micronutrient whose lack in Indian diets can stunt the growth of young children and make them more vulnerable to diarrhea and pneumonia.
“At least 10 such ‘biofortified’ wheat varieties have been released and are grown on over 2 million hectares in India,” said Velu Govindan, CIMMYT breeder who leads the Center’s wheat biofortification research. “It is now standard practice to label all new varieties for biofortified traits to raise awareness and adoption, and CIMMYT has included high grain zinc content among its primary breeding objectives, so we expect that nearly all wheat lines distributed by CIMMYT in the next 5-8 years will have this trait.”
A rigorous study published in 2018 showed that, when vulnerable young children in India ate foods prepared with such zinc-biofortified wheat, they experienced significantly fewer days of pneumonia and vomiting than would normally be the case.
Celebrating joint achievements and committing for continued success
The April-June 2018 edition of the “ICAR Reporter” newsletter called the five-decade ICAR-CIMMYT partnership in agricultural research “…one of the longest and most productive in the world…” and mentioned mutually beneficial research in the development and delivery of stress resilient and nutritionally enriched wheat, impact-oriented sustainable and climate-smart farming practices, socioeconomic analyses, and policy recommendations.
Speaking during an August 2022 visit to India by CIMMYT Director General Bram Govaerts, Himanshu Pathak, secretary of the Department of Agricultural Research and Education (DARE) of India’s Ministry of Agriculture and Farmers Welfare and Director General of ICAR, “reaffirmed the commitment to closely work with CIMMYT and BISA to address the current challenges in the field of agricultural research, education and extension in the country.”
“The ICAR-CIMMYT collaboration is revolutionizing wheat research and technology deployment for global food security,” said Gyanendra Singh, director, ICAR-IIWBR. “This in turn advances global peace and prosperity.”
India and CIMMYT wheat transformers meet in India in February, 2023. From left to right: Two students from the Indian Agricultural Research Institute (IARI); Arun Joshi, CIMMYT regional representative for Asia; Rajbir Yadav, former Head of Genetics, IARI; Gyanendra Singh, Director General, Indian Institute of Wheat and Barley Research (IIWBR); Bram Govaerts, CIMMYT director general; Harikrishna, Senior Scientist, IARI. (Photo: CIMMYT)
According to Govaerts, CIMMYT has concentrated on strategies that foster collaboration to deliver greater value for the communities both ICAR and the Center serve. “The way forward to the next milestone — say, harvesting 125 million tons of wheat from the same or less land area — is through our jointly developing and making available new, cost effective, sustainable technologies for smallholder farmers,” he said.
Wheat research and development results to date, challenges, and future initiatives occupied the table at the 28th All India Wheat & Barley Research Workers’ Meeting, which took place in Udaipur, state of Rajasthan, August 28-30, 2023, and which ICAR and CIMMYT wheat scientists attended.
Generous funding from various agencies, including the following, have supported the work described: The Australian Centre for International Agricultural Research (ACIAR), the Bill & Melinda Gates Foundation, the Federal Ministry for Economic Cooperation and Development of Germany (BMZ), the Foreign, Commonwealth & Development Office of UK’s Government (FCDO), the Foundation for Food & Agricultural Research (FFAR), HarvestPlus, ICAR, the United States Agency for International Development (USAID), funders of the One CGIAR Accelerated Breeding Initiative (ABI), and the Plant Health Initiative (PHI).
The devastating disease wheat blast is a threat to crop production in many South Asian countries. In Bangladesh, it was first identified in seven southern and southwestern districts in 2016, and later spread to 27 others causing significant damage. The International Maize and Wheat Improvement Center (CIMMYT) is working with the Bangladesh Wheat and Maize Research Institute (BWMRI) and other national partners to conduct research and extension activities to mitigate the ongoing threat.
From March 1-10, 2023, a group of 46 wheat researchers, government extension agents, and policy makers from ten countries — Bangladesh, Brazil, China, Ethiopia, India, Japan, Mexico, Nepal, Sweden, and Zambia — gathered in Jashore, Bangladesh to learn about and exchange experiences regarding various wheat diseases, particularly wheat blast. Following the COVID-19 pandemic, this was the first in-person international wheat blast training held in Bangladesh. It focused on the practical application of key and tricky elements of disease surveillance and management strategies, such as resistance breeding and integrated disease management.
Training participants get hands-on practice using a field microscope, Bangladesh. (Photo: Ridoy/CIMMYT)
“This is an excellent training program,” said Shaikh Mohammad Bokhtiar, executive chairman of the Bangladesh Agriculture Research Council (BARC), during the opening session. “Participants will learn how to reduce the severity of the blast disease, develop and expand blast resistant varieties to farmers, increase production, and reduce imports.”
This sentiment was echoed by Golam Faruq, director general of BWMRI. “This program helps in the identification of blast-resistant lines from across the globe,” he said. “From this training, participants will learn to manage the devastating blast disease in their own countries and include these learnings into their national programs.”
Hands-on training
The training was divided into three sections: lectures by national and international scientists; laboratory and field experiment visits; and trips to farmers’ fields. Through the lecture series, participants learned about a variety of topics including disease identification, molecular detection, host-pathogen interaction, epidemiology and integrated disease management.
Hands-on activities were linked to working on the Precision Phenotyping Platform (PPP), which involves the characterization of more than 4,000 wheat germplasm and releasing several resistant varieties in countries vulnerable to wheat blast. Participants practiced taking heading notes, identifying field disease symptoms, tagging, and scoring disease. They conducted disease surveillance in farmers’ fields in Meherpur and Faridpur districts — both of which are extremely prone to wheat blast — observing the disease, collecting samples and GPS coordinates, and completing surveillance forms.
Muhammad Rezaul Kabir, senior wheat breeder at BWMRI, explains the Precision Phenotyping Platform, Bangladesh. (Photo: Md. Harun-Or-Rashid/CIMMYT)
Participants learned how to use cutting-edge technology to recognize blast lesions in leaves using field microscopes. They went to a pre-installed spore trapping system in a farmer’s field to learn about the equipment and steps for collecting spore samples, observing them under a compound microscope, and counting spores. They also visited the certified seed production fields of Shawdesh Seed, a local company which has played an important role in promoting wheat blast resistant varieties BARI Gom 33 and BWMRI Gom 3 regionally, and Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU) in Gazipur to see current wheat blast research in action.
Blast-resistance in Bangladesh
“I am so happy to see the excellent infrastructure and work ethics of staff that has made possible good science and impactful research come out of the PPP,” said Aakash Chawade, associate professor in Plant Breeding at the Swedish University of Agricultural Sciences. “Rapid development of blast-resistant varieties and their dissemination will help Bangladesh mitigate the effects of wheat blast, not only inside the country but by supporting neighboring ones as well.”
Training participants scout and score disease in a blast-infected wheat field, Bangladesh. (Photo: Md. Harun-Or-Rashid/CIMMYT)
“Besides the biotic and abiotic challenges faced in wheat production, climate change and the Russia-Ukraine crisis are further creating limitations to wheat production and marketing,” said Pawan Kumar Singh, head of Wheat Pathology at CIMMYT and lead organizer of the training. “Due to the development of blast-resistant wheat varieties and its commercial production under integrated disease management practices, the domestic production of wheat in Bangladesh has increased and there is increased interest from farmers in wheat.”
Dave Hodson, a principal scientist at CIMMYT and one of the training’s resource speakers, added: “This is a remarkable success that researchers developed two blast resistant varieties in Bangladesh urgently. It was only achievable because of the correct measures taken by the researchers and support of Government policies.”
However, there are still some barriers to widespread adoption of these varieties. As such, in parallel to other activities, a team from Bangladesh Agricultural University (BAU) joined the field trip to meet local farmers and conduct research into the socio-economic factors influencing the adoption and scaling of relevant wheat varieties.
Delegates with other officials in front of the seminar room. (Photo: Biswajit/BWMRI)
Representatives from Australian Centre for International Agricultural Research (ACIAR) and Bangladesh Agricultural Research Council (BARC) paid a visit to Bangladesh to see the valuable work of the Precision Phenotyping Platform (PPP).
PPP was established in response to the devastating wheat blast disease, which was first reported in the country in 2016.
Technical and financial support from the International Maize and Wheat Improvement Center (CIMMYT), the Australian Commission for International Agricultural Research and the Australian Centre for International Agricultural Research, along with other funders, has contributed to the effort to combat the disease.
This is achieved by generating precise data for wheat blast resistance in germplasm in Bangladesh, as well as other wheat growing countries. This PPP has been used to screen elite lines and genetic resources from various countries.
On February 16 and 17, 2023, two groups of national and international delegations visited the BWMRI-CIMMYT collaborative research platform PPP at the BWMRI regional station in Jashore, Bangladesh.
The first group was made up of representatives from both the Australian Commission for International Agricultural Research and the Australian Centre for International Agricultural Research. This included seven commissioners under the direction of Fiona Simson, along with ACIAR senior officials from Australia and India.
The other group was from BARC, which was led by Executive Chairman Shaikh Mohammad Bokhtiar, along with Golam Faruq, Director General of BWMRI, and Andrew Sharpe, Bangabandhu Research Chair, Global Institute of Food Security (GIFS), University of Saskatchewan in Canada.
Both delegations were welcomed by Muhammad Rezaul Kabir, the Senior Wheat Breeder at BWMRI. Kabir gave a brief presentation about the platform and other wheat blast collaborative research programs in the seminar room.
The delegations then went to the PPP field, where BWMRI researchers Kabir and Robiul Islam, as well as CIMMYT researcher Md. Harun-Or-Rashid, explained further information about the BWMRI-CIMMYT collaborative research. Both commissioners and delegates appreciated seeing the work being conducted in person by the national and international collaborations of BWMRI and CIMMYT on wheat blast research.
Visitors observing blast disease symptoms in wheat leaves. (Photo: Muhammad Rezaul Kabir/BWMRI)
“It is important, innovative work, that is affecting not only Bangladesh but many countries around the world that are now starting to be concerned about the impacts of wheat blast,” commissioner Simson said. “This study is very important for Australia and we are pleased to be contributing to it.”
Lindsay Falvey, another commissioner, added, “This is a wonderful experiment, using high-level science and technologies to combat wheat blast in Bangladesh. The experiment is well-planned. Overall, it is an excellent platform.”
ACIAR delegate Eric Huttner added to the praise for the project. “The platform is performing extremely well for the purpose of evaluating lines, resistance to the disease and that’s very useful for Bangladesh and rest of the world,” he said. “This is a gift that Bangladesh is giving to the neighboring countries to protect wheat.”
The delegates pledged to share their expert advice with the Minister of Foreign Affairs in Bangladesh in order to increase investments and improve facilities for agricultural research programs in the country.
Golam Faruq, Director General of BWMRI discussing the PPP with Shaikh Mohammad Bokhtiar, Executive Chairman of BARC (Photo: Md. Harun-Or-Rashid/CIMMYT)
“This is an excellent work,” Executive Chairman of BARC, Bokhtiar said. “We can get more information from screening activities by using bioinformatics tools and training people through the BARC-GIFS program.”
Pawan Kumar Singh, Head of Wheat Pathology at CIMMYT-Mexico and Project Leader, coordinated the visits virtually and expressed his thanks to the delegations for their visit to the platform. This PPP, within a short span of few years, has been highly impactful, characterizing more than 15,000 entries and releasing several resistant varieties in countries vulnerable to wheat blast.
Cutting-edge models for crops and crop diseases, boosted by high-resolution climate datasets, could propel the development of early warning systems for wheat blast in Asia, helping to safeguard farmers’ grain supplies and livelihoods from this deadly and mysterious crop disease, according to a recent study by scientists at the International Maize and Wheat Improvement Center (CIMMYT).
Originally from the Americas, wheat blast shocked farmers and experts in 2016 by striking 15,000 hectares of Bangladesh wheat fields, laying waste to a third of the crops. The complex interactions of wheat and the fungus, Magnaporthe oryzae pathotype Triticum (MoT), which causes blast, are not fully understood. Few current wheat varieties carry genetic resistance to it and fungicides only partly control it. Warm temperatures and high humidity favor MoT spore production and spores can fly far on winds and high-altitude currents.
Mean potential wheat blast disease infections (NPI) across Asia, based on disease and crop infection model simulations using air temperature and humidity data from 1980-2019. Black dots represent wheat growing areas with presumably unsuitable climates for wheat blast. The x and y axes indicate longitude and latitude.
“Using a wheat blast infection model with data for Asia air temperatures and humidity during 1980-2019, we found high potential for blast on wheat crops in Bangladesh, Myanmar, and areas of India, whereas the cooler and drier weather in countries such as Afghanistan and Pakistan appear to render their wheat crops as unlikely for MoT establishment,” said Carlo Montes, a CIMMYT agricultural climatologist and first author of the paper, published in the International Journal of Biometeorology. “Our findings and approach are directly relevant for work to strengthen monitoring and forecasting tools for wheat blast and other crop diseases, as well as building farmers’ and agronomists’ disease control capacity.”
Montes emphasized the urgency of those efforts, noting that some 13 million hectares in South Asia are sown to wheat in rotation with rice and nearly all the region’s wheat varieties are susceptible to wheat blast.
Md. Sayedul Islam inaugurated the greenhouse complex along with Golam Faruq and Md. Benojir Alam. (Credit: Timothy J. Krupnik/CIMMYT)
A new greenhouse complex, built with financial support from the International Maize and Wheat Improvement Center (CIMMYT), at the Bangladesh Wheat and Maize Research Institute (BWMRI) was inaugurated on 13 August 2022. The greenhouse was built at BWMRI’s headquarters in Dinajpur, Bangladesh.
This complex has a room for generator, a sample preparation room and space for a small laboratory. These upgrades will add new momentum for greenhouse activities and BWMRI and CIMMYT scientists designed the facility to accommodate wheat scientists from Bangladesh and other countries.
The BWMRI has been working to combat wheat blast disease since 2016, with financial and technical support from CIMMYT and other investors. CIMMYT has also assisted the Government of Bangladesh in developing an early warning system for wheat blast.
Because of the challenging phenology of synthetic wheat and introductions from winter and facultative wheat zones, field condition evaluation of these germplasm is difficult and the greenhouse will help ease this hurdle. Additionally, several pathological experiments investigating the biology of wheat blast will now be able to be performed in the new greenhouse facility.
Supplementary activities at the greenhouse include disease screening and research into unlocking the genetics of host resistance. The installation of a diesel generator will keep the greenhouse running in case of power outages.
Visitors to the newly constructed greenhouse at the Bangladesh Wheat and Maize Research Institute. (Credit: Rezaul Kabir/BWMRI)
Md. Sayedul Islam, Secretary of the Ministry of Agriculture, inaugurated the greenhouse complex. Additional attendees at the opening included Shaikh Mohammad Bokhtiar, Executive Chairman of the Bangladesh Agricultural Research Council (BARC), Golam Faruq, Director General of BWMRI, Mirza Mofazzal Islam, Director General of the Bangladesh Institute of Nuclear Agriculture (BINA), Debasish Sarker, Director General of the Bangladesh Agricultural Research Institute (BARI), Md. Benojir Alam, Director General of the Department of Agricultural Extension (DAE), and Md. Abdul Wadud, Executive Director and Additional Secretary at the Bangladesh Institute of Research and Training on Applied Nutrition (BIRTAN). Timothy J. Krupnik, country representative of CIMMYT in Bangladesh, was also present.
Genomic selection identifies individual plants based on the information from molecular markers, DNA signposts for genes of interest, that are distributed densely throughout the wheat genome. For wheat blast, the results can help predict which wheat lines hold promise as providers of blast resistance for future crosses and those that can be advanced to the next generation after selection.
In this study, scientists from the International Maize and Wheat Improvement Center (CIMMYT) and partners evaluated genomic selection by combining genotypic data with extensive and precise field data on wheat blast responses for three sets of genetically diverse wheat lines and varieties, more than 700 in all, grown by partners at locations in Bangladesh and Bolivia over several crop cycles.
The study also compared the use of a small number of molecular markers linked to the 2NS translocation, a chromosome segment from the grass species Aegilops ventricosa that was introduced into wheat in the 1980s and is a strong and stable source of blast resistance, with predictions using thousands of genome-wide markers. The outcome confirms that, in environments where wheat blast resistance is determined by the 2NS translocation, genotyping using one-to-few markers tagging the translocation is enough to predict the blast response of wheat lines.
Finally, the authors found that selection based on a few wheat blast-associated molecular markers retained 89% of lines that were also selected using field performance data, and discarded 92% of those that were discarded based on field performance data. Thus, both marker-assisted selection and genomic selection offer viable alternatives to the slower and more expensive field screening of many thousands of wheat lines in hot-spot locations for the disease, particularly at early stages of breeding, and can speed the development of blast-resistant wheat varieties.
The research was conducted by scientists from the International Maize and Wheat Improvement Center (CIMMYT), the Bangladesh Wheat and Maize Research Institute (BWMRI), the Instituto Nacional de Innovación Agropecuaria y Forestal (INIAF) of Bolivia, the Borlaug Institute for South Asia (BISA) and the Indian Council of Agricultural Research (ICAR) in India, the Swedish University of Agricultural Sciences (Alnarp), and Kansas State University in the USA. Funding for the study was provided by the Bill & Melinda Gates Foundation, the Foreign and Commonwealth Development Office of the United Kingdom, the U.S. Agency for International Development (USAID), the CGIAR Research Program on Wheat (WHEAT), the Indian Council of Agricultural Research (ICAR), the Swedish Research Council, and the Australian Centre for International Agricultural Research (ACIAR).
Cover photo: A researcher from Bangladesh shows blast infected wheat spikes and explains how the disease directly attacks the grain. (Photo: Chris Knight/Cornell University)
As wheat blast continues to infect crops in countries around the world, researchers are seeking ways to stop its spread. The disease — caused by the Magnaporthe oryzae pathotype Triticum — can dramatically reduce crop yields, and hinder food and economic security in the regions in which it has taken hold.
Researchers from the International Maize and Wheat Improvement Center (CIMMYT) and other international institutions looked into the potential for wheat blast to spread, and surveys existing tactics used to combat it. According to them, a combination of methods — including using and promoting resistant varieties, using fungicides, and deploying strategic agricultural practices — has the best chance to stem the disease.
The disease was originally identified in Brazil in 1985. Since then, it has spread to several other countries in South America, including Argentina, Bolivia and Paraguay. During the 1990s, wheat blast impacted as many as three million hectares in the region. It continues to pose a threat.
Through international grain trade, wheat blast was introduced to Bangladesh in 2016. The disease has impacted around 15,000 hectares of land in the country and reduced average yields by as much as 51% in infected fields.
Because the fungus’ spores can travel on the wind, it could spread to neighboring countries, such as China, India, Nepal and Pakistan — countries in which wheat provides food and jobs for billions of people. The disease can also spread to other locales via international trade, as was the case in Bangladesh.
“The disease, in the first three decades, was spreading slowly, but in the last four or five years its pace has picked up and made two intercontinental jumps,” said Pawan Singh, CIMMYT’s head of wheat pathology, and one of the authors of the recent paper.
In the last four decades, wheat blast has appeared in South America, Asia an Africa. (Video: Alfonso Cortés/CIMMYT)
The good fight
Infected seeds are the most likely vector when it comes to the disease spreading over long distances, like onto other continents. As such, one of the key wheat blast mitigation strategies is in the hands of the world’s governments. The paper recommends quarantining potentially infected grain and seeds before they enter a new jurisdiction.
Governments can also create wheat “holidays”, which functionally ban cultivation of wheat in farms near regions where the disease has taken hold. Ideally, this would keep infectable crops out of the reach of wheat blast’s airborne and wind-flung spores. In 2017, India banned wheat cultivation within five kilometers of Bangladesh’s border, for instance. The paper also recommends that other crops — such as legumes and oilseed — that cannot be infected by the wheat blast pathogen be grown in these areas instead, to protect the farmers’ livelihoods.
Other tactics involve partnerships between researchers and agricultural workers. For instance, early warning systems for wheat blast prediction have been developed and are being implemented in Bangladesh and Brazil. Using weather data, these systems alert farmers when the conditions are ideal for a wheat blast outbreak.
Researchers are also hunting for wheat varieties that are resistant to the disease. Currently, no varieties are fully immune, but a few do show promise and can partially resist the ailment depending upon the disease pressure. Many of these resistant varieties have the CIMMYT genotype Milan in their pedigree.
“But the resistance is still limited. It is still quite narrow, basically one single gene,” Xinyao He, one of the co-authors of the paper said, adding that identifying new resistant genes and incorporating them into breeding programs could help reduce wheat blast’s impact.
Wheat spikes damaged by wheat blast. (Photo: Xinyao He/CIMMYT)
The more the merrier
Other methods outlined in the paper directly involve farmers. However, some of these might be more economically or practically feasible than others, particularly for small-scale farmers in developing countries. Wheat blast thrives in warm, humid climates, so farmers can adjust their planting date so the wheat flowers when the weather is drier and cooler. This method is relatively easy and low-cost.
The research also recommends that farmers rotate crops, alternating between wheat and other plants wheat blast cannot infect, so the disease will not carry over from one year to the next. Farmers should also destroy or remove crop residues, which may contain wheat blast spores. Adding various minerals to the soil, such as silicon, magnesium, and calcium, can also help the plants fend off the fungus. Another option is induced resistance, applying chemicals to the plants such as jasmonic acid and ethylene that trigger its natural resistance, much like a vaccine, Singh said.
Currently, fungicide use, including the treatment of seeds with the compounds, is common practice to protect crops from wheat blast. While this has proven to be somewhat effective, it adds additional costs which can be hard for small-scale farmers to swallow. Furthermore, the pathogen evolves to survive these fungicides. As the fungus changes, it can also gain the ability to overcome resistant crop varieties. The paper notes that rotating fungicides or developing new ones — as well as identifying and deploying more resistant genes within the wheat — can help address this issue.
However, combining some of these efforts in tandem could have a marked benefit in the fight against wheat blast. For instance, according to Singh, using resistant wheat varieties, fungicides, and quarantine measures together could be a time-, labor-, and cost-effective way for small-scale farmers in developing nations to safeguard their crops and livelihoods.
“Multiple approaches need to be taken to manage wheat blast,” he said.
A blast-blighted stalk of wheat. (Photo: Chris Knight/Cornell)
Every year, the spores of the wheat blast fungus lie in wait on farms in South America, Bangladesh, and beyond. In most years, the pathogen has only a small impact on the countries’ wheat crops. But the disease spreads quickly, and when the conditions are right there’s a risk of a large outbreak — which can pose a serious threat to the food security and livelihood of farmers in a specific year.
To minimize this risk, an international partnership of researchers and organizations have created the wheat blast Early Warning System (EWS), a digital platform that notifies farmers and officials when weather conditions are ideal for the fungus to spread. The team, which began its work in Bangladesh, is now introducing the technology to Brazil — the country where wheat blast was originally discovered in 1985.
The International Maize and Wheat Improvement Center (CIMMYT), the Brazilian Agricultural Research Corporation (EMBRAPA), Brazil’s University of Passo Fundo (UPF) and others developed the tool with support from USAID under the Cereal Systems Initiative for South Asia (CSISA) project.
Although first developed with the help of Brazilian scientists for Bangladesh, the EWS has now come full circle and is endorsed and being used by agriculture workers in Brazil. The team hopes that the system will give farmers time to take preventative measures against the disease.
Outbreaks can massively reduce crop yields, if no preventative actions are taken.
“It can be very severe. It can cause a lot of damage,” says Maurício Fernandes, a plant epidemiologist with EMBRAPA.
Striking first
In order to expand into a full outbreak, wheat blast requires specific temperature and humidity conditions. So, Fernandes and his team developed a digital platform that runs weather data through an algorithm to determine the times and places in which outbreaks are likely to occur.
If the system sees a region is going to grow hot and humid enough for the fungus to thrive, it sends an automated message to the agriculture workers in the area. These messages — texts or emails — alert them to take preemptive measures against the disease.
More than 6,000 extension agents in Bangladesh have already signed up for disease early warnings.
In Brazil, Fernandes and his peers are connecting with farmer cooperatives. These groups, which count a majority of Brazilian farmers as members, can send weather data to help inform the EWS, and can spread alerts through their websites or in-house applications.
Wheat blast can attack a plant quickly, shriveling and deforming the grain in less than a week from the first symptoms. Advance warnings are essential to mitigate losses. The alerts sent out will recommend that farmers apply fungicide, which only works when applied before infection.
“If the pathogen has already affected the plant, the fungicides will have no effect,” Fernandes says.
A blast from the past
Because wheat had not previously been exposed to Magnaporthe oryzae, most wheat cultivars at the time had no natural resistance to Magnaporthe oryzae, according to Fernandes. Some newer varieties are moderately resistant to the disease, but the availability of sufficient seed for farmers remains limited.
The pathogen can spread through leftover infected seeds and crop residue. But its spores can also travel vast distances through the air.
If the fungus spreads and infects enough plants, it can wreak havoc over large areas. In the 1990s — shortly after its discovery — wheat blast impacted around three million hectares of wheat in South America. Back in 2016, the disease appeared in Bangladesh and South Asia for the first time, and the resulting outbreak covered around 15,000 hectares of land. CGIAR estimates that the disease has the potential to reduce the region’s wheat production by 85 million tons.
In Brazil, wheat blast outbreaks can have a marked impact on the country’s agricultural output. During a major outbreak in 2009, the disease affected as many as three million hectares of crops in South America. As such, the EWS is an invaluable tool to support food security and farmer livelihoods. Fernandes notes that affected regions can go multiple years between large outbreaks, but the threat remains.
“People forget about the disease, then you have an outbreak again,” he says.
Essential partnerships
The EWS has its roots in Brazil. In 2017 Fernandes and his peers published a piece of research proposing the model. After that, Tim Krupnik, a senior scientist and country representative with CIMMYT in Bangladesh, along with a group of researchers and organizations, launched a pilot project in Bangladesh.
There, agriculture extension officers received an automated email or text message when weather conditions were ideal for wheat blast to thrive and spread. The team used this proof of concept to bring it back to Brazil.
According to Krupnik, the Brazil platform is something of a “homecoming” for this work. He also notes that cooperation between the researchers, organizations and agriculture workers in Brazil and Bangladesh was instrumental in creating the system.
“From this, we’re able to have a partnership that I think will have a significant outcome in Brazil, from a relatively small investment in research supplied in Bangladesh. That shows you the power of partnerships and how solutions can be found to pressing agricultural problems through collaborative science, across continents,” he says.
Genetic analyses show that a destructive wheat blast fungus that travelled from South America to South East Asia is now established in Zambia under rain-fed conditions, according to a new report from The Sainsbury Laboratory.
Wheat fields at Toluca station, Mexico. (Photo: Fernando Delgado/CIMMYT)
On December 11, 2020, the Nepal Agricultural Research Council (NARC) announced the release of six new wheat varieties for multiplication and distribution to the country’s wheat farmers, offering increased production for Nepal’s nearly one million wheat farmers and boosted nutrition for its 28 million wheat consumers.
The varieties, which are derived from materials developed by the International Maize and Wheat Improvement Center (CIMMYT), include five bred for elevated levels of the crucial micronutrient zinc, and Borlaug 100, a variety well known for being high yielding, drought- and heat-resilient, and resistant to wheat blast, as well as high in zinc.
“Releasing six varieties in one attempt is historic news for Nepal,” said CIMMYT Asia Regional Representative and Principal Scientist Arun Joshi.
“It is an especially impressive achievement by the NARC breeders and technicians during a time of COVID-related challenges and restrictions,” said NARC Executive Director Deepak Bhandari.
“This was a joint effort by many scientists in our team who played a critical role in generating proper data, and making a strong case for these varieties to the release committee, ” said Roshan Basnet, head of the National Wheat Research Program based in Bhairahawa, Nepal, who was instrumental in releasing three of the varieties, including Borlaug 2020.
“We are very glad that our hard work has paid off for our country’s farmers,” said Dhruba Thapa, chief and wheat breeder at NARC’s National Plant Breeding and Genetics Research Centre.
Nepal produces 1.96 million tons of wheat on more than 750,000 hectares, but its wheat farmers are mainly smallholders with less than 1-hectare holdings and limited access to inputs or mechanization. In addition, most of the popular wheat varieties grown in the country have become susceptible to new strains of wheat rust diseases.
The new varieties — Zinc Gahun 1, Zinc Gahun 2, Bheri-Ganga, Himganga, Khumal-Shakti and Borlaug 2020 — were bred and tested using a “fast-track” approach, with CIMMYT and NARC scientists moving material from trials in CIMMYT’s research station in Mexico to multiple locations in Nepal and other Target Population of Environments (TPEs) for testing.
“Thanks to a big effort from Arun Joshi and our NARC partners we were able to collect important data in first year, reducing the time it takes to release new varieties,” said CIMMYT Head of Wheat Improvement Ravi Singh.
The varieties are tailored for conditions in a range of wheat growing regions in the country — from the hotter lowland, or Terai, regions to the irrigated as well as dryer mid- and high-elevation areas — and for stresses including wheat rust diseases and wheat blast. The five high-zinc, biofortified varieties were developed through conventional crop breeding by crossing modern high yielding wheats with high zinc progenitors such as landraces, spelt wheat and emmer wheat.
“Zinc deficiency is a serious problem in Nepal, with 21% of children found to be zinc deficient in 2016,” explained said CIMMYT Senior Scientist and wheat breeder Velu Govindan, who specializes in breeding biofortified varieties. “Biofortification of staple crops such as wheat is a proven method to help reverse and prevent this deficiency, especially for those without access to a more diverse diet.”
Borlaug 2020 is equivalent to Borlaug 100, a highly prized variety released in 2014 in adbMexico to commemorate the centennial year of Nobel Peace laureate Norman E. Borlaug. Coincidently, its release in Nepal coincides with the 50th anniversary of Borlaug’s Nobel Peace Prize.
NARC staff have already begun the process of seed multiplication and conducting participatory varietal selection trials with farmers, so very soon farmers throughout the country will benefit from these seeds.
“The number of new varieties and record release time is amazing,” said Joshi. “We now have varieties that will help Nepal’s farmers well into the future.”
CIMMYT breeding of biofortified varieties was funded by HarvestPlus. Variety release and seed multiplication activities in Nepal were supported by NARC and the Asian Development Bank (ADB) through collaboration with ADB Natural Resources Principal & Agriculture Specialist Michiko Katagami. This NARC-ADB-CIMMYT collaboration was prompted by World Food Prize winner and former HarvestPlus CEO Howarth Bouis, and provided crucial support that enabled the release in a record time.
The International Maize and Wheat 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 Research 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.
ABOUT NARC:
Nepal Agricultural Research Council (NARC) was established in 1991 as an autonomous organization under Nepal Agricultural Research Council Act – 1991 to conduct agricultural research in the country to uplift the economic level of Nepalese people.
ABOUT ADB:
The Asian Development Bank (ADB) is committed to achieving a prosperous, inclusive, resilient, and sustainable Asia and the Pacific, while sustaining its efforts to eradicate extreme poverty. It assists its members and partners by providing loans, technical assistance, grants, and equity investments to promote social and economic development.
Pawan Kumar Singh, head, wheat pathology, International Maize and Wheat Improvement Center (CIMMYT) says that the fast-acting and devastating fungal disease known as wheat blast was first spotted in Africa in the Zambian rainfed wheat production system in the 2017-2018 crop cycle.
For the first time, wheat blast, a fast-acting and devastating fungal disease, has been reported 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).
