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 ïŹrst 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.
âThis 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,â 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.
âWheat 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)
âThe 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,â said Golam Faruq, BWMRIâs 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)
âThe 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,â said Professor Diane Saunders from the John Innes Centre, UK.
Regional partners examine the CIMMYT maize lines displayed during field day. (Photo: CIMMYT)
The International Maize Improvement Consortium for Africa (IMIC-Africa) held its Southern Africa field day on 25 March 2024 at Harare, Zimbabwe. IMIC-Africa, launched by CIMMYT in 2018, is a public-private partnership designed to strengthen maize breeding programs of partner institutions in Africa. As part of this initiative, CIMMYT organizes annual field days which bring together representatives from seed companies and national agricultural research system (NARS) partners across Zimbabwe and Kenya.
At the heart of the IMIC-Africa field day lies a vibrant showcase of genetically diverse materials developed from various maize breeding pipelines of CIMMYT in Southern Africa. Such events serve as a catalyst to drive innovations in maize breeding programs, deliver solutions to stakeholders, and enable seed companies and NARS partners to make informed selections tailored to local contexts.
âIt is an important forum to have organized discussions with partners, and redesignâwhere possibleâour breeding approaches to deliver targeted products to stakeholders,â said Director of CIMMYTâs Global Maize Program, One CGIAR Global Maize Breeding Lead, and One CGIAR Plant Health Initiative Lead, B.M. Prasanna. âThe main stakeholders here are our partners, including seed companies and public sector national programs, through whom we reach out to farming communities.â
The significance of these field days cannot be overstated. It allows the partners to have a critical look at the breeding materials on display and undertake selections of maize lines relevant to their breeding programs. In addition, the IMIC-Africa field days enable CIMMYT team to have structured dialogues with diverse stakeholders and to review and refine breeding (line and product development) strategies and approaches.
“It is key to bridge the gap between the national programs and private sector players. This platform allows us to stay ahead in terms of research, and innovative breakthroughs in the seed sector,â added Kabamba Mwansa, principal agriculture research officer, ZARI, Zambia and Southern Africa Breeding, and seed systems network coordinator.
Highlights from the Harare field day
With an impressive array of 737 CIMMYT maize lines on display, partners at the Harare field day gained insights about the performance of different materials. The materials span early-, intermediate-, and late- maturity groups to nutritious maize breeding pipelines. This comprehensive showcase enabled seed companies and NARS partners to make informed selections, tailored to their local contexts. The material on display ranged from early generation (one or two years of testing data) to advanced generation (more than three years of testing) coming from the Southern Africa breeding pipelines targeting multiple market segments.
Regional partners examine the CIMMYT maize lines displayed during field day. (Photo: CIMMYT)
One of the strategic priorities of CIMMYT’s maize breeding program in Africa is improving the nutritional quality of maize. This is exemplified by the development of provitamin A-enriched maize (PVA). On display were 169 lines originating from the PVA-enriched maize breeding pipeline. The efforts underscore CIMMYTâs commitment to address regional nutritional needs through targeted breeding initiatives.
Felix Jumbe, a partner from Peacock Seeds in Malawi reflected on the importance of the IMIC-Africa partnership. âWe have been part of IMIC-Africa since its inception, and we continue to appreciate the different climate-resilient lines emerging from CIMMYT maize breeding programs in Africa. Last year, we sold out of our seed as people continue to appreciate the need for resilient maize varieties. The drought-tolerant (DT) maize lines from the consortium have been a huge selling point as most farmers are happy with it,â he said.
The field day not only showcased cutting-edge breeding innovations but also offered a historical perspective by tracing the trajectory of the most popular lines taken up under IMIC-Africa from 2019 to 2023. This served as a crucial reference point for partners, enabling them to assess the performance of newly displayed lines against established benchmarks. Furthermore, partners considered the presence of trait donors as invaluable in improving resistance to key biotic stresses or tolerance to certain abiotic stresses prevalent in Africa.
CIMMYT, NARS, and seed company partners participate in the IMIC-Africa field day in Harare, Zimbabwe. (Photo: CIMMYT)
CIMMYT partnership continues to add value
In the face of escalating environmental pressures, including climate change and pest infestations such as the fall armyworm (FAW), CIMMYT breeders have been working tirelessly to develop resilient varieties capable of withstanding these challenges. Partners such as SeedCo have embraced these robust varieties. For breeder Tariro Kusada, it is her second year of attending the IMIC- Africa field day. âWe continue to see value in getting breeding materials through IMIC. The vigor from the lines on display is outstanding as compared to last year. We hope the vigor translates to yield.â
Danny Mfula from Synergy Zambia reinforced the value of the partnership. âIt is always good to tap into CIMMYT’s germplasm to supplement what we have. We are glad that more FAW-tolerant hybrids are coming on board. We want to leverage on these developments as farmers have gone through a lot of challenges to control FAW,â he said.
As the harvest stage approaches, partners can select their material by assessing the performance of the lines from flowering to grain filling stages. Each plot’s harvest provides invaluable insights, guiding partners in their selections. Partners are also given the opportunity to view the improved maize lines from CIMMYT through a virtual gallery of ears from each plot, ensuring informed decision-making. By fostering dialogue, facilitating partnerships, and highlighting genetic innovations, the field days catalyze progress towards a more sustainable and resilient future for African agriculture.
Maize grain heavily damaged by the larger grain borer and maize weevil. (Photo: Jessica GonzĂĄlez/CIMMYT)
According to the World Health Organization (WHO), 10% of the global population suffers from food poisoning each year. Aflatoxins, the main contributor to food poisoning around the world, contaminate cereals and nuts and humans, especially vulnerable groups like the young, elderly, or immune-compromised, and animals are susceptible to their toxic and potentially carcinogenic effects.
Fungi contamination occurs all along the production cycle, during and after harvest, so the mitigation of the mycotoxins challenge requires the use of an integrated approach, including the selection of farmer-preferred tolerant varieties, implementing good agricultural practices such as crop rotation or nitrogen management, reducing crop stress, managing pests and diseases, biological control of mycotoxigenic strains, and good post-harvest practices.
Monitoring of mycotoxins in food crops is important to identify places and sources of infestations as well as implementing effective agricultural practices and other corrective measures that can prevent outbreaks.
A bug problem
Insects can directly or indirectly contribute to the spread of fungi and the subsequent production of mycotoxins. Many insects associated with maize plants before and after harvest act as a vector by carrying fungal spores from one location to another.
International collaboration is key to managing the risks associated with the spread of invasive pests and preventing crop damage caused by the newly introduced pests. CIMMYT, through CGIARâs Plant Health initiative, partners with the Center for Grain and Animal Health Research of the US Department of Agriculture (USDA) and Kansas State University are investigating the microbes associated with the maize weevil and the larger grain borer.
The experiment consisted of trapping insects in three different habitats, a prairie near CIMMYT facilities in El BatĂĄn, Texcoco, Mexico, a maize field, and a maize store at CIMMYTâs experimental station at El BatĂĄn, using Lindgren funnel traps and pheromones lures.
Hanging of the Lindgren funnel traps in a prairie near El BĂĄtan, Texcoco, Mexico. (Photo: Jessica GonzĂĄlez/CIMMYT)
Preliminary results of this study were presented by Hannah Quellhorst from the Department of Entomology at Kansas State University during an online seminar hosted by CIMMYT.
The collected insect samples were cultured in agar to identify the microbial community associated with them. Two invasive pests, the larger grain bore and the maize weevil, a potent carcinogenic mycotoxin was identified and associated with the larger grain borer and the maize weevil.
The larger grain borer is an invasive pest, which can cause extensive damage and even bore through packaging materials, including plastics. It is native to Mexico and Central America but was introduced in Africa and has spread to tropical and subtropical regions around the world. Together with the maize weevil, post-harvest losses of up to 60% have been recorded in Mexico from these pests.
âWith climate change and global warming, there are risks of these pests shifting their habitats to areas where they are not currently present like sub-Saharan Africa and North Africa,â said Quelhorst. âHowever, the monitoring of the movement of these pests at an international level is lacking and the microbial communities moving with these post-harvest insects are not well investigated.â
Maize is a staple crop in Zimbabwe, playing a vital role in the countryâs agricultural landscape as food for its own people and an export good. However, behind every successful maize harvest lies the quality of seed and resistance to diseases and stresses.
Amidst the multitude of diseases that threaten maize crops, one adversary is maize lethal necrosis (MLN). Though not native to Zimbabwe, it is crucial to remain prepared for its potential impact on food security.
What is maize lethal necrosis?
MLN is a viral disease, caused by a combination of two virus diseases. The disease emerged in Kenya in 2011 and quickly spread to other countries in eastern Africa. The introduction of MLN to Africa was likely affected by the movement of infected seed and insect vectors. MLN has had a severe impact on regional maize production, leading to yield losses of up to 90%.
Recognizing the need to equip seasoned practitioners with the knowledge and skills to effectively diagnose and manage MLN, CIMMYT organized a comprehensive training on MLN diagnosis and management, targeting 25 representatives from Zimbabweâs Plant Quarantine Services.
From students to experienced technicians, pathologists and plant health inspectors, this was an opportunity to refresh their knowledge base or an introduction to the important work of MLN mitigation. âThis training for both advanced level practitioners and students is crucial not only for building competence on MLN but also to refresh minds to keep abreast and be prepared with approaches to tackle the disease once it is identified in the country,â said Nhamo Mudada, head of Plant Quarantine Services.
Expectations were diverse, ranging from sharpening understanding of key signs and symptoms to learning from country case examples currently ridden with the disease. With CIMMYTâs guidance, practitioners learned how to identify MLN infected plants, make accurate diagnoses, and implement management strategies to minimize losses.
âFor over 10 years, these trainings have been important to raise awareness, keep local based practitioners up to speed, help them diagnose MLN, and make sure that they practice proper steps to tackle this disease,â said L.M Suresh, CIMMYT maize pathologist and head of the MLN screening facility in Kenya.
Identifying the specific MLN causing viral disease affecting a maize plant is the first step in combating MLN. Determining whether it is a biotic or abiotic disease is critical in establishing its cause and subsequent diagnosis. By implementing proper diagnostic techniques and understanding the fundamentals of good diagnosis, practitioners can bring representative samples to the lab and accurately identify MLN.
Tackling MLN in Zimbabwe
Initiated in 2015 at Mazowe as a joint initiative between the Government of Zimbabwe and CIMMYT, a modern quarantine facility was built to safely import maize breeding materials from eastern Africa to southern Africa and enable local institutions to proactively breed for resistance against MLN.
The MLN quarantine facility at the Plant Quarantine Institute is run by the Department of Research and Specialist Services (DRSS) and is mandated to screen maize varieties imported under strict quarantine conditions to ensure that they are MLN-free.
Training participants pose outside of the MLN screening facilities. (Photo: CIMMYT)
To date, CIMMYT and partners have released 22 MLN resistant and tolerant hybrids in eastern Africa. CIMMYT’s research and efforts to combat MLN have focused on a multidimensional approach, including breeding for resistant varieties, promoting integrated pest management strategies, strengthening seed systems, and enhancing the capacity of farmers and stakeholders.
âSupport extended through valuable partnerships between CIMMYT, and the collaborations have played a pivotal role from surveillance to diagnostics and building capacity,â said Mudada.
Feedback and insights
Chief Plant Health Inspector for Export and Imports Biosecurity, Monica Mabika, expressed gratitude for the training. âIt is always an honor when we have expert pathologists come through and provide a valuable refresher experience, strengthening our understanding on issues around biosecurity and learning what other countries are doing to articulate MLN,â she said.
Students learn how to screen maize plants for MLN. (Photo: CIMMYT)
Among the students was Audrey Dohwera from the University of Zimbabwe, who acknowledged the importance of the training. âI have been attached for 2 months under the pathology department, and I was eager to learn about MLN, how to detect signs and symptoms on maize, how to address it and be able to share with fellow farmers in my rural community,â she said.
With the knowledge gained from this training, practitioners are well equipped to face the challenges that MLN may present, ultimately safeguarding the countryâs maize production status.
India can applaud a hallmark in national food production: in 2023, the harvest of wheatâIndiaâs second most important food cropâwill surpass 110 million tons for the first time.
This maintains India as the worldâs 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 Revolutionâthe modernization of Indiaâs agriculture during the 1960s-70s that allowed the country to put behind it the recurrent grain shortages and extreme hunger of preceding decades.
âNewer and superior wheat varieties in India continually provide higher yields and genetic resistance to the rusts and other deadly diseases,â said Distinguished Scientist Emeritus at CIMMYT, Ravi Singh. âMore 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 Centerâs international yield trials and nurseries or developed locally using CIMMYT parents.â
Wheat grain yield in Indian farmersâ fields rose yearly by more than 1.8 percentâsome 54 kilograms per hectareâin 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.
âThe 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,â Singh explained. âThis both protected their crops and delivered breeding gains for yield and climate resilience.â
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)
âThis âzero tillageâ 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,â said Arun Joshi, CIMMYT wheat breeder and regional representative for Asia and managing director of the Borlaug Institute for South Asia (BISA). âAlso, 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.â
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. âAdded 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.â
To safeguard Indiaâs wheat crops from the fearsome disease wheat blast, native to the Americas but which struck Bangladeshâs 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.
âMore than a dozen wheat blast resistant varieties have been deployed in eastern India to block the diseaseâs entry and farmers in areas adjoining Bangladesh have temporarily stopped growing wheat,â said Pawan Singh, head of wheat pathology at CIMMYT.
Building on wheatâs 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.
âAt least 10 such âbiofortifiedâ wheat varieties have been released and are grown on over 2 million hectares in India,â said Velu Govindan, CIMMYT breeder who leads the Centerâs wheat biofortification research. âIt 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.â
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 âICAR Reporterâ newsletter called the five-decade ICAR-CIMMYT partnership in agricultural research ââŠone of the longest and most productive in the worldâŠâ 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 Indiaâs Ministry of Agriculture and Farmers Welfare and Director General of ICAR, âreaffirmed 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.â
âThe ICAR-CIMMYT collaboration is revolutionizing wheat research and technology deployment for global food security,â said Gyanendra Singh, director, ICAR-IIWBR. âThis in turn advances global peace and prosperity.â
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. âThe way forward to the next milestone â say, harvesting 125 million tons of wheat from the same or less land area â is through our jointly developing and making available new, cost effective, sustainable technologies for smallholder farmers,â he said.
Wheat research and development results to date, challenges, and future initiatives occupied the table at the 28th All India Wheat & Barley Research Workersâ 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 UKâs 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).
