Tag: Maize Lethal Necrosis

Agricultural solutions to tackle humanity’s climate crisis

Written by Mike Listman on December 3, 2019. Posted in Features.

More than 11,000 scientists signed on to a recent report showing that planet Earth is facing a climate emergency and the United Nations warned that the world is on course for a 3.2 degree spike by 2100, even if 2015 Paris Agreement commitments are met.

Agriculture, forestry, and land-use change are implicated in roughly a quarter of global greenhouse gas emissions.

Agriculture also offers opportunities to mitigate climate change and to help farmers — particularly smallholders in developing and emerging economies who have been hardest hit by hot weather and reduced, more erratic rainfall.

Most of CIMMYT’s work relates to climate change, helping farmers adapt to shocks while meeting the rising demand for food and, where possible, reducing emissions.

Family farmer Geofrey Kurgat (center) with his mother Elice Tole (left) and his nephew Ronny Kiprotich in their 1-acre field of Korongo wheat near Belbur, Nukuru, Kenya. (Photo: Peter Lowe/CIMMYT)

Climate-resilient crops and farming practices

53 million people are benefiting from drought-tolerant maize. Drought-tolerant maize varieties developed using conventional breeding provide at least 25% more grain than other varieties in dry conditions in sub-Saharan Africa — this represents as much as 1 ton per hectare more grain on average. These varieties are now grown on nearly 2.5 million hectares, benefiting an estimated 6 million households or 53 million people in the continent. One study shows that drought-tolerant maize can provide farming families in Zimbabwe an extra 9 months of food at no additional cost. The greatest productivity results when these varieties are used with reduced or zero tillage and keeping crop residues on the soil, as was demonstrated in southern Africa during the 2015-16 El Niño drought. Finally, tolerance in maize to high temperatures in combination with drought tolerance has a benefit at least twice that of either trait alone.

Wheat yields rise in difficult environments. Nearly two decades of data from 740 locations in more than 60 countries shows that CIMMYT breeding is pushing up wheat yields by almost 2% each year — that’s some 38 kilograms per hectare more annually over almost 20 years — under dry or otherwise challenging conditions. This is partly through use of drought-tolerant lines and crosses with wild grasses that boost wheat’s resilience. An international consortium is applying cutting-edge science to develop climate-resilient wheat. Three widely-adopted heat and drought-tolerant wheat lines from this work are helping farmers in Pakistan, a wheat powerhouse facing rising temperatures and drier conditions; the most popular was grown on an estimated 40,000 hectares in 2018.

Climate-smart soil and fertilizer management. Rice-wheat rotations are the predominant farming system on more than 13 million hectares in the Indo-Gangetic Plains of South Asia, providing food and livelihoods for hundreds of millions. If farmers in India alone fine-tuned crop fertilizer dosages using available technologies such as cellphones and photosynthesis sensors, each year they could produce nearly 14 million tons more grain, save 1.4 million tons of fertilizer, and cut CO₂-equivalent greenhouse gas emissions by 5.3 million tons. Scientists have been studying and widely promoting such practices, as well as the use of direct seeding without tillage and keeping crop residues on the soil, farming methods that help capture and hold carbon and can save up to a ton of CO₂ emissions per hectare, each crop cycle. Informed by CIMMYT researchers, India state officials seeking to reduce seasonal pollution in New Delhi and other cities have implemented policy measures to curb the burning of rice straw in northern India through widespread use of zero tillage.

Farmers going home for breakfast in Motoko district, Zimbabwe. (Photo: Peter Lowe/CIMMYT)

Measuring climate change impacts and savings

In a landmark study involving CIMMYT wheat physiologists and underlining nutritional impacts of climate change, it was found that increased atmospheric CO₂ reduces wheat grain protein content. Given wheat’s role as a key source of protein in the diets of millions of the poor, the results show the need for breeding and other measures to address this effect.

CIMMYT scientists are devising approaches to gauge organic carbon stocks in soils. The stored carbon improves soil resilience and fertility and reduces its emissions of greenhouse gases. Their research also provides the basis for a new global soil information system and to assess the effectiveness of resource-conserving crop management practices.

CIMMYT scientist Francisco Pinto operates a drone over wheat plots at CIMMYT's experimental station in Ciudad Obregon, Mexico. (Photo: Alfonso Cortés/CIMMYT) — CIMMYT scientist Francisco Pinto operates a drone over wheat plots at CIMMYT’s experimental station in Ciudad Obregon, Mexico. (Photo: Alfonso Cortés/CIMMYT)

Managing pests and diseases

Rising temperatures and shifting precipitation are causing the emergence and spread of deadly new crop diseases and insect pests. Research partners worldwide are helping farmers to gain an upper hand by monitoring and sharing information about pathogen and pest movements, by spreading control measures and fostering timely access to fungicides and pesticides, and by developing maize and wheat varieties that feature genetic resistance to these organisms.

Viruses and moth larvae assail maize. Rapid and coordinated action among public and private institutions across sub-Saharan Africa has averted a food security disaster by containing the spread of maize lethal necrosis, a viral disease which appeared in Kenya in 2011 and quickly moved to maize fields regionwide. Measures have included capacity development with seed companies, extension workers, and farmers the development of new disease-resilient maize hybrids.

The insect known as fall armyworm hit Africa in 2016, quickly ranged across nearly all the continent’s maize lands and is now spreading in Asia. Regional and international consortia are combating the pest with guidance on integrated pest management, organized trainings and videos to support smallholder farmers, and breeding maize varieties that can at least partly resist fall armyworm.

New fungal diseases threaten world wheat harvests. The Ug99 race of wheat stem rust emerged in eastern Africa in the late 1990s and spawned 13 new strains that eventually appeared in 13 countries of Africa and beyond. Adding to wheat’s adversity, a devastating malady from the Americas known as “wheat blast” suddenly appeared in Bangladesh in 2016, causing wheat crop losses as high as 30% on a large area and threatening to move quickly throughout South Asia’s vast wheat lands.

In both cases, quick international responses such as the Borlaug Global Rust Initiative, have been able to monitor and characterize the diseases and, especially, to develop and deploy resistant wheat varieties.

A community volunteer of an agricultural cooperative (left) uses the Plantix smartphone app to help a farmer diagnose pests in his maize field in Bardiya district, Nepal. (Photo: Bandana Pradhan/CIMMYT)

Partners and funders of CIMMYT’s climate research

A global leader in publicly-funded maize and wheat research and related farming systems, CIMMYT is a member of CGIAR and leads the South Asia Regional Program of the CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS).

CIMMYT receives support for research relating to climate change from national governments, foundations, development banks and other public and private agencies. Top funders include CGIAR Research Programs and Platforms, the Bill & Melinda Gates Foundation, Mexico’s Secretary of Agriculture and Rural Development (SADER), the United States Agency for International Development (USAID), the UK Department for International Development (DFID), the Australian Centre for International Agricultural Research (ACIAR), Cornell University, the German aid agency GIZ, the UK Biotechnology and Biological Sciences Research Council (BBSRC), and CGIAR Trust Fund Contributors to Window 1 &2.

L.M. Suresh (center-right), Maize Pathologist at CIMMYT and Head of the MLN Screening Facility, facilitates a training on MLN with national partners. (Photo: CIMMYT)

How a disease without borders was contained

Written by Rodrigo Ordóñez on November 25, 2019. Posted in Features.

It’s been eight years since maize lethal necrosis (MLN) was first reported on the African continent. When it appeared in Kenya’s Bomet County in 2011, a sense of panic swept across the maize sector. Experts quickly realized that all maize varieties on the market were susceptible to this viral disease, which could wipe out entire maize fields.

Spearheaded by the International Maize and Wheat Improvement Center (CIMMYT), a rapid regional response involving national agriculture research systems (NARS), national plant protection organizations and seed sector partners was set up. The response involved multiple approaches: rigorous surveillance, epidemiology research, disease management across the seed value chain, and screening and fast-tracking of the MLN-tolerant maize breeding program.

Now, CIMMYT and its partners are reflecting on the tremendous impact of transboundary coalition to contain the devastating disease.

“Country reports show there are now much less incidents of MLN in the region. We have effectively contained this disease as no new country in sub-Saharan Africa reported MLN since Ethiopia in 2014. This is a great achievement of an effective public private partnership,” noted B.M. Prasanna, Director of CIMMYT’s Global Maize Program and the CGIAR Research Program on Maize.

He was speaking at the closure workshop for the MLN Diagnostics and Management project and the MLN Epidemiology project on October 15-17, 2019, in Nairobi, Kenya. Experts from research, plant health and seed sector organizations from eastern and southern Africa reflected on the tremendous impact of the transboundary coalition to contain MLN across the region.

“The outbreak of the disease in Uganda in 2012 was a huge challenge as all the maize varieties and hybrids on the market were susceptible. With the support of CIMMYT and other partners in the national agriculture research systems, we got access to Bazooka, a high-yielding, drought- and MLN-tolerant maize variety that has helped in containing the disease,” said Godfrey Katwere, marketing manager for NASECO.

Until now, 19 MLN-tolerant and -resistant hybrids have been released, helping to keep the disease away from farmers’ fields and to stop its spillover to non-endemic countries in sub-Saharan Africa.

CIMMYT team members check for traces of the maize chlorotic mottle virus (MCMV) in maize plants during a visit to the MLN screening facility in Naivasha, Kenya. (Photo: Joshua Masinde/CIMMYT)

Science in action

The MLN screening facility, established in Naivasha in 2013, has been key to a better understanding of the disease and to setting up MLN hybrid tolerance and resistance breeding efforts. The facility, funded by the Bill & Melinda Gates Foundation and the Syngenta Foundation for Sustainable Agriculture, has supported public and private partners to screen over 200,000 germplasm with around 300,000 rows of maize.

State-of-the-art epidemiology research has been carried out to identify how the disease could be transmitted and the best diagnostics methods along the seed value chain.

MLN is caused by the combination of the maize chlorotic mottle virus (MCMV) and any of the viruses belonging to the Potyviridae family.

As part of the project, studies showed that moist soil had higher MCMV virus loads than dry soil. The studies — conducted by Benham Lockhart of University of Minnesota and Peg Redinbaugh, a professor at Ohio State University and Research Leader and Research Plant Molecular Geneticist at USDA — indicated that MCMV can stay active in runoff water, and helped in understanding how the disease is transmitted and how to define management protocols.

“Crop debris may also act as source of MCMV inoculum but for a limited period of up to two months,” said L.M. Suresh, CIMMYT Maize Pathologist, in reference to soil transmission studies conducted by CIMMYT. “A host-free period of two months is, therefore, recommended for effective management of MLN,” he noted.

Rapid and low-cost MLN-causing virus detection methods such as immunostrips and ELISA-based tests were adopted at scale.

“After optimizing the protocols for MLN viruses’ diagnosis suitable for African systems, we transferred these technologies to [national plant protection organizations] and seed companies, not just within the endemic countries but also to the non-endemic countries in southern and west Africa, through intensive trainings,” Prasanna explained. “We created a digital MLN surveillance tool under the Open Data Kit (ODK) app for NPPOs and other stakeholders to effectively carry out MLN surveillance on the ground. The survey information is captured in real time in farmers’ and seed production fields coupled with rapid immunostrips MLN tests,” he remarked.

According to Francis Mwatuni, Project Manager of the MLN Diagnostics and Management project, this proactive and collaborative surveillance network has been an important outcome that helped curb MLN from spreading to non-endemic regions. “In 2016, we only had 625 surveillance points. By 2019, the surveillance points in all the target countries stood at 2,442, which intensified the alertness on MLN presence and how to effectively deal with it,” Mwatuni said. In total, 7,800 surveillance points were covered during the project implementation period.

Over 100 commercial seed firms have also been trained on how to produce MLN-free seed to facilitate trade within the endemic nations and to ensure the disease is not transferred to the non-endemic countries via contaminated seeds.

Participants at the MLN projects closure workshop stand for a group photo. (Photo: Joshua Masinde/CIMMYT)

Sustaining the fight

Researchers continue to work to lessen MLN’s resurgence or new outbreaks. In 2018, incidents in all endemic countries, except Ethiopia, declined sharply. One suggested explanation for the upsurge in Ethiopia, especially in the northwestern region, was reduced use of pesticide for fall armyworm control, as compared to previous years where heavy application of these pesticides also wiped out MLN insect vectors, such as maize thrips and aphids.

At the end of the projects, partners urged for the scale-up of second-generation MLN-tolerant and -resistant varieties. They explained farmers would fully benefit from recent genetic gains of the new improved varieties and its protection against MLN.

“Despite the success registered, MLN is still a major disease requiring constant attention. We cannot rest as we redirect our energies at sustaining and building on the gains made,” said Beatrice Pallangyo, principal agricultural officer in Tanzania’s Ministry of Agriculture, Food Security and Cooperatives.

After the success containing MLN, stakeholders suggested the need to stay alert on other transboundary pests and diseases such as the tar spot complex, which could be a major threat to Africa’s food security in case of an outbreak.

Seed production innovations, conservation agriculture and partnerships are key for Africa’s food security

Written by Jérôme Bossuet on September 11, 2019. Posted in Features.

Members of the International Maize Improvement Consortium Africa (IMIC – Africa) and other maize and wheat research partners discovered the latest innovations in seed and agronomy at Embu and Naivasha research stations in Kenya on August 27 and 28, 2019. The International Maize and Wheat Improvement Center (CIMMYT) and the Kenya Agriculture & Livestock Research Organization (KALRO) held their annual partner field days to present sustainable solutions for farmers to cope with poor soils, a changing climate and emerging diseases and pests, such as wheat rust, maize lethal necrosis or fall armyworm.

Versatile seeds and conservation agriculture offer farmers yield stability

“Maize is food in Kenya. Wheat is also gaining importance for our countries in eastern Africa,” KALRO Embu Center Director, Patrick Gicheru, remarked. “We have been collaborating for many years with CIMMYT on maize and wheat research to develop and disseminate improved technologies that help our farmers cope against many challenges,” he said.

Farmers in Embu, like in most parts of Kenya, faced a month delay in the onset of rains last planting season. Such climate variability presents a challenge for farmers in choosing the right maize varieties. During the field days, CIMMYT and KALRO maize breeders presented high-yielding maize germplasm adapted to diverse agro-ecological conditions, ranging from early to late maturity and from lowlands to highlands.

João Saraiva, from the Angolan seed company Jardins d’Ayoba, said having access to the most recent improved maize germplasm is helpful for his young seed company to develop quality seeds adapted to farmers’ needs. He is looking for solutions against fall armyworm, as the invasive species is thriving in the Angolan tropical environment. He was interested to hear about CIMMYT’s progress to identify promising maize lines resistant to the caterpillar. Since fall armyworm was first observed in Africa in 2016, CIMMYT has screened almost 1,200 inbred lines and 2,900 hybrids for tolerance to fall armyworm.

“Hopefully, we will be developing and releasing the first fall armyworm-tolerant hybrids by the first quarter of 2020,” announced B.M. Prasanna, director of CIMMYT’s Global Maize Programme and the CGIAR Research Program on Maize (MAIZE).

“Through continuous innovations to build varieties that perform well despite dry spells, heat waves or disease outbreak, maize scientists have been able to deliver significant yield increases each year across various environments,” explained Prasanna. “This genetic gain race is important to respond to growing grain demands despite growing climate risks and declining soil health.”

Berhanu Tadesse, maize breeder at the Ethiopian Institute for Agricultural Research (EIAR), was highly impressed by the disease-free, impeccable green maize plants at Embu station, remembering the spotted and crippled foliage during a visit more than a decade ago. This was “visual proof of constant progress,” he said.

For best results, smallholder farmers should use good agronomic practices to conserve water and soil health. KALRO agronomist Alfred Micheni demonstrated different tillage techniques during the field tour including the furrow ridge, which is adapted to semi-arid environments because it retains soil moisture.

Late maturity hybrid demonstration plot at Embu station. (Photo: Jérôme Bossuet/CIMMYT)

Innovations for a dynamic African seed sector

A vibrant local seed industry is needed for farmers to access improved varieties. Seed growers must be able to produce pure, high-quality seeds at competitive costs so they can flourish in business and reach many smallholder farmers.

Double haploid technology enables breeders to cut selection cycles from six to two, ultimately reducing costs by one third while ensuring a higher level of purity. Sixty percent of CIMMYT maize lines are now developed using double haploid technology, an approach also available to partners such as the Kenyan seed company Western Seeds.

The Seed Production Technology for Africa (SPTA) project, a collaboration between CIMMYT, KALRO, Corteva Agriscience and the Agricultural Research Council, is another innovation for seed companies enabling cheaper and higher quality maize hybrid production. Maize plants have both female and male pollen-producing flowers called tassels. To produce maize hybrids, breeders cross two distinct female and male parents. Seed growers usually break the tassels of female lines manually to avoid self-pollination. SPTA tested a male sterility gene in Kenya and South Africa, so that female parents did not produce pollen, avoiding a detasseling operation that damages the plant. It also saves labor and boosts seed yields. Initial trial data showed a 5 to 15% yield increase, improving the seed purity as well.

World-class research facilities to fight new and rapidly evolving diseases

The KALRO Naivasha research station has hosted the maize lethal necrosis (MLN) quarantine and screening facility since 2013. Implementing rigorous phytosanitary protocols in this confined site enables researchers to study the viral disease first observed in Africa 2011 in Bomet country, Kenya. Working with national research and plant health organizations across the region and the private sector, MLN has since been contained.

A bird’s eye view of the demonstration plots is the best testimony of the impact of MLN research. Green patches of MLN-resistant maize alternate with yellow, shrivelled plots. Commercial varieties are susceptible to the disease that can totally wipe out the crop, while new MLN-resistant hybrids yield five to six tons per hectare. Since the MLN outbreak in 2011, CIMMYT has released 19 MLN-tolerant hybrids with drought-tolerance and high-yielding traits as well.

Maize Lethal Necrosis (MLN) sensitive and resistant hybrid demo plots in Naivasha’s quarantine & screening facility (Photo: KIPENZ/CIMMYT)

A major challenge to achieving food security is to accelerate the varietal replacement on the market. CIMMYT scientists and partners have identified the lengthy and costly seed certification process as a major hurdle, especially in Kenya. The Principal Secretary of the State Department for Research in the Ministry of Agriculture, Livestock, and Fisheries, Hamadi Boga, pledged to take up this issue with the Kenya Plant and Health Inspectorate Service (KEPHIS).

“Such rapid impact is remarkable, but we cannot rest. We need more seed companies to pick up these new improved seeds, so that our research reaches the maximum number of smallholders,’’ concluded Prasanna.

Ethiopian maize breeders will directly apply knowledge gained from training

Written by Leslie Domínguez on September 10, 2019. Posted in News.

Training attendees outside the Rift Valley Hotel in Adama, Ethiopia. (Photo: CIMMYT)

From July 22–26, the Stress Tolerant Maize for Africa (STMA) project organized a training in Adama, Ethiopia to update maize technicians on recent developments in maize research, data collection and seed production. The training was designed to stimulate good breeding programs, good data collection in trial and nurseries, production of better quality seed and development of improved varieties. Around 25 trainees attended, mainly from maize breeding research centers. Similar trainings were conducted in all STMA project countries over the last three and a half years.

CIMMYT staff from Ethiopia, Kenya and Zimbabwe and staff from the Ethiopian Institute of Agricultural Research (EIAR) Bako Research Center delivered training on methodologies and gave practical demonstrations on tablets. Presentations focused on the origin and botany of the maize plant, constraints to maize production in Ethiopia, data collection, breeding for abiotic stresses, new tools for phenotyping, maize lethal necrosis (MLN), and seed quality control.

Mandefro Nigussie, Director General of EIAR, said that the training was important because it addressed data collection. “If we are missing the data, we are missing the investment of the country,” he noted. He recognized CIMMYT’s culture in empowering research centers through trainings. The role of EIAR is to generate, test, disseminate and scale technologies. Therefore, having technicians who are aware of the recent developments in their areas is crucial.

Cosmos Magorokosho, maize breeder and STMA project leader, said that the core components of the training were to give technicians a strong understanding of the basics of maize and the physiology of maize plant. The knowledge they gained from this training will support them during data collection and when breeding for resistance to diseases and pests and improved seed production.

Upon completing five days training, all trainees received certificates along with the presentations and other relevant documents for future reference. CIMMYT maize breeder Dagne Wegary said he appreciated the active participation and dedication of the trainees and the interest they showed to improve their knowledge and skills. He reminded them that this is the start of a long journey and they will have to use the knowledge and skills gained to help farmers produce more and ensure food security. Trainees reflected that the training increased their existing knowledge in maize breeding and helped them to understand the current developments in the area. They said they would directly apply what they have learned and transfer the knowledge to other colleagues working in maize breeding.

Breaking Ground: Breeder Marcela C. Andrade bolsters maize with hardiness from ancestral races

Written by Mike Listman on January 16, 2019. Posted in Features.

As the world heats up and water grows scarce, threatening the productivity of humankind’s preferred crops, breeder Marcela Carvalho Andrade and her colleagues at the International Maize and Wheat Improvement Center (CIMMYT) are working to toughen maize, drawing resilience traits from landraces, the forerunners of modern maize.

For decades, scientists have sought to utilize the hardiness of maize landraces, which evolved over millennia of farmer selection for adaptation to diverse and sometimes harsh local settings in Mexico, Central and South America.

But crossing elite varieties with landraces brings along wild traits that are difficult and costly to purge, including lower grain yields, excessive tallness or a tendency to fall over in strong winds. For this and for their genetic complexity, landraces are seldom used directly in breeding programs, according to Andrade.

Crosses that home in on genetically complex traits

“Our strategy is to cross selected landraces with elite maize lines, thus developing improved lines that can be directly incorporated and recycled in breeding programs,” explained Andrade, who joined CIMMYT in 2016.

The traits sought include better resilience under high temperatures, drought conditions or the attacks of rapidly-evolving crop diseases. “All these features will be critical for the future productivity of maize,” said Andrade.

One of the world’s three most important crops, maize contributes over 20% of the calories in human diets in 21 low-income countries, as well as being used in industry, biofuels, and feed for livestock and poultry.

Andrade and the maize breeding team develop new lines that carry a 75 percent genetic contribution from the elite source and 25 percent from a landrace. The aim she said is to get the good components from both sides, while broadening maize’s genetic diversity for use by breeders and ultimately farmers.

The resulting lines and hybrids are tested for yield, resilience and overall agronomic performance, under both normal growing conditions and “stressed” environments; for example, in plots grown at sites with high temperatures or reduced water availability.

“We can thus identify landraces that offer traits of interest, as well as generating improved breeding lines to strengthen the resilience of elite maize without reducing its yield,” said Andrade, noting that the research employs conventional cross-pollination and selection.

According to Andrade, CIMMYT has carried out large-scale molecular analysis of its maize seed collections, which number around 28,000 and comprise landraces from 70 countries.

“Over the past years, CIMMYT has used genetic diversity analyses of its maize collections to select landraces for use in drought tolerance breeding or for finding lines that are resistant to newly important diseases such as Maize Lethal Necrosis or Tar Spot,” she explained. “Genetic diversity analysis allows us to narrow the number of candidate landrace sources that we need to cross and assess in the field.”

The viral disease Maize Lethal Necrosis (MLN) has devastated crops in eastern Africa since its appearance there in 2011.

The researchers have also found landrace sources of resilience against Tar Spot Complex, a maize disease of the Americas that can cause 50 percent or greater yield losses in infected crops.

Benefiting breeding and farmers

Andrade said the breeding team expects to release a first wave of landrace-derived, improved maize lines in 2019, some featuring enhanced drought tolerance and others that provide better resistance to Tar Spot.

“The lines we offer will be freely available to breeders worldwide and must yield well and show superior resilience,” Andrade explained. “They will have reasonable agronomics—ear and plant height and standability, for example. The lines will not be perfect, but breeders won’t hesitate to use them because we’ve ensured that they are superior for at least one crucial trait and reasonably competitive for most other traits.”

From Brazil to the world

Growing up in a small town and having direct contact with her father’s dairy farm in Minas Gerais, a mainly rural state in Brazil, Andrade finds her CIMMYT work enormously satisfying. “My dad and a few uncles were farmers and complained some years that their crops didn’t yield well,” she says. “I knew I wanted to help them somehow.”

Andrade obtained Bachelor and Master’s degrees in agronomy/plant science from the Universidade Federal de Lavras (UFLA), one of Brazil’s premier institutions of higher education. She later completed a Doctorate in Genetics and Plant Breeding at UFLA, in partnership with Ohio State University.

She credits CIMMYT maize scientist Terry Molnar, her supervisor and mentor, with teaching her the complex ins and outs of maize breeding. “I am a plant breeder and worked previously with vegetables, but I learned the practical aspects of maize breeding from Terry.”

Looking ahead, Andrade sees herself continuing as a plant breeder. “I don’t see myself working in anything else. I would eventually like to lead my own program but, at this point in my career, I’m happy to help transfer landrace traits to modern maize varieties.”

Screening cycle for deadly MLN virus set to begin in Kenya during 2019

Written by on December 11, 2018. Posted in News.

*CIMMYT partners visit the Maize Lethal Necrosis screening facility in Kenya. (Photo: Joshua Masinde/CIMMYT)*

The maize lethal necrosis (MLN) artificial inoculation screening site in Naivasha, Kenya, will begin its phenotyping (screening/ indexing) cycle of 2019 at the beginning of January 2019 and in other four intervals throughout the year. Interested organizations from both the private and public sectors are invited to send maize germplasm for screening.

In 2013, the International Maize and Wheat Improvement Center (CIMMYT) and the Kenya Agricultural & Livestock Research Organization (KALRO) jointly established the MLN screening facility at the KALRO Naivasha research station in Kenya’s Rift Valley with support from the Bill & Melinda Gates Foundation and the Syngenta Foundation for Sustainable Agriculture.

MLN was first discovered in Kenya in 2011 and quickly spread to other parts of eastern Africa; the disease causes premature plant death and unfilled, poorly formed maize cobs, and can lead to up to 100 percent yield loss in farmers’ fields.

CIMMYT and partners are dedicated to stopping the spread of this deadly maize disease by effectively managing the risk of MLN on maize production through screening and identifying MLN-resistant germplasm. The MLN screening facility supports countries in sub-Saharan Africa to screen maize germplasm (for hybrid, inbred and open pollinated varieties) against MLN in a quarantined environment.

This is the largest dedicated MLN screening facility in East Africa. Since its inception in 2013, the facility has evaluated more than 180,000 accessions (more than 270,000 rows of maize) from more than 15 multinational and national seed companies and national research programs.

Partners can now plan for annual MLN Phenotyping (Screening / Indexing) during 2019 with the schedule below. The improved and streamlined approach for MLN phenotyping should enable our partners to accelerate breeding programs to improve resistance for Maize MLN for sub-Saharan Africa.

2019 annual phenotyping (indexing / screening) schedule:

When the seeds are available	Planting Period – Planned	MLN Screening / Indexing
December	Second Week of January	MLN Indexing
March	Second week of April	MLN Screening
June	Second Week of July	MLN Indexing
August	Second Week of September	MLN Screening
October	Second week of November	MLN Indexing

More information about the disease and resources for farmers can be found on CIMMYT’s MLN portal.

Please note that it can take up to six weeks to process imports and clear shipments.

For assistance in obtaining import permits and necessary logistics for the upcoming screening, please contact:

Dr. L.M. Suresh
Tel: +254 20 7224600 (direct)
Email: l.m.suresh@cgiar.org

CIMMYT–Kenya, ICRAF House
United Nations Avenue, Gigiri
P.O. Box 1041–00621
Nairobi, Kenya.

Delegates of the 3-year review conference pose for a group photograph at the ICRAF Campus in Nairobi. (Photo: Joshua Masinde/CIMMYT)

International coalition keeps devastating maize disease at bay, but risks still linger

Written by Jérôme Bossuet on December 10, 2018. Posted in Features.

NAIROBI, Kenya (CIMMYT) — When maize lethal necrosis (MLN) was first reported in Bomet County, Kenya, in September 2011 and spread rapidly to several countries in eastern Africa, agricultural experts feared this emerging maize disease would severely impact regional food security. However, a strong partnership across eight countries between maize research, plant health organizations and the private seed sector has, so far, managed to contain this devastating viral disease, which can wipe out entire maize fields. As another emerging pest, the fall armyworm, is making headlines in Africa, African countries could learn a lot from the initiatives to combat MLN on how to rapidly respond to emerging crop pests and diseases.

On November 19-20, 2018, the International Maize and Wheat Improvement Center (CIMMYT), national research and plant protection agencies and seed companies met in Nairobi to review the third year’s progress of the MLN Diagnostics and Management Project, supported by USAID. All participants agreed that preventing any spread of the disease into southern Africa was a great success.

“The fact that we all responded rapidly and productively to this crisis serves as a testament of the success of our collective efforts,” said CIMMYT’s Global Maize Program Director, B.M. Prasanna, while addressing delegates from Ethiopia, Kenya, Malawi, Rwanda, Tanzania, Uganda, Zambia and Zimbabwe. “That no new country has reported the MLN outbreak since Ethiopia last reported it in the 2014-2015 period, and that we have managed to keep it at bay from southern Africa and west Africa is no mean feat. It would have been a major food security disaster if the disease had spread throughout sub-Saharan Africa.”

However, the MLN Community of Practice warned that risks of severe outbreaks remain, with new cases of MLN reported during the MLN 2018 survey in several parts of Uganda.

Delegates from Rwanda discuss the country's workplan at the 3-year MLN project review. (Photo: Joshua Masinde/CIMMYT) — *Delegates from Rwanda discuss the country’s workplan at the 3-year MLN project review. (Photo: Joshua Masinde/CIMMYT)*

Rapid response to a food security threat

MLN is caused by the combination of the maize chlorotic mottle virus (MCMV) and other common cereal viruses mostly from the potyviridae family — a set of viruses that encompasses over 30 percent of known plant viruses — like the sugarcane mosaic virus (SCMV). This viral disease can result in up to 100 percent yield loss and has devastated the incomes and food security situation of many smallholder farmers in the region.

CIMMYT, in collaboration with national agricultural research institutions, national plant protection agencies and seed sector partners, developed a multi-layered response system including real-time intensive surveillance, screening, and fast-tracking of the MLN resistance breeding program. Thanks to the MLN Screening Facility in Naivasha, Kenya, maize breeders rapidly discovered that most popular maize varieties were susceptible, which could expose poor farmers to the risk of losing their entire maize crops.

Using its global collection of maize lines and numerous crop improvement innovations, CIMMYT was able to develop and release at least 15 MLN-resistant maize varieties in just 2 to 3 years.

One important step was to understand how the disease spread. Epidemiologists quickly pointed out the necessity to work with the seed companies and farmers, as the virus could be transmitted through seeds. The project helped put in place the protocols for seed firms to adhere to for their products to be MLN-free. Affordable and simple seed treatment procedures yielded promising results. The project also created awareness on better farming methods for effective disease control.

National Plant Protection Organizations were mobilized to create intensive awareness. They were also equipped and trained on low-cost innovative field diagnostic tools like MLN immunostrips and the deployment of GPS-based mobile surveillance and reporting systems.

“For the first time, Rwanda was able to conduct a comprehensive survey on MLN in farmers’ fields, commercial seed fields and at agro-dealers. We are glad that through MLN management and awareness programs within the project, MLN incidences have declined,” said Fidele Nizeyimana, maize breeder and pathologist at the Rwanda Agricultural Board (RAB) and the MLN Surveillance team lead in Rwanda.

“Equally important is that the commercial seed sector took the responsibility of testing their seed production fields, made sure that seed exchange is done in a responsible manner and implemented voluntary monitoring and surveillance within their fields,” remarked Francis Mwatuni, MLN project manager at CIMMYT.

“I am happy that Malawi has maintained its MLN-free status as per the intensive MLN surveillance activities we conducted in the country over the last three years,” noted Johnny Masangwa, senior research officer and MLN Surveillance team lead in Malawi. “We are now able to monitor both seed and grain movement through our borders for MLN traces, courtesy of the lab equipment, reagents and training on laboratory analysis we received through the project”.

B.M. Prasanna, director of the CGIAR Research Program on Maize (MAIZE), discusses what the CGIAR offers in rapid response preparedness to newly emerging pests, diseases and crises.

The maize sector should remain vigilant

Daniel Bomet, maize breeder at Uganda’s National Agricultural Research Organization (NARO), warned that with new infections reported in the northern parts of his country, the maize sector needs to remain alert to the threat of MLN. “We need to step up MLN awareness and management programs, and require seed companies to follow the right procedures to produce MLN-free seeds to arrest this trend,” he said.

Tanzania Seed Association Executive Director, Bob Shuma, also warned that MLN could be spreading to the southern highlands of the country as the virus was detected in some seed shipments from three seed companies operating in that region. A comprehensive MLN survey in Tanzania will hopefully soon give an idea of the countrywide status of the disease in the country.

Conference speakers and participants noted that inefficient regulatory processes in maize seed variety release and deployment still stand in the way of rapid release of MLN resistant varieties to farmers across the region.

“How quickly we scale up and deploy the elite MLN-resistant and stress-tolerant varieties to the farmer is the next most important phase of the project,” Prasanna said.

The Kenya Plant Health Inspectorate Service (KEPHIS) General Manager, Phytosanitary Services, Isaac Macharia, said that with the support of the USAID Feed the Future program, the government agency has set up a team dedicated to assisting seed companies doing seed multiplication to fast-track the release of the MLN-resistant varieties to the market. Some Kenyan seed companies announced they will market MLN-resistant varieties for the next cropping season in March 2019.

As the project enters its last year, the MLN Community of Practice looks to ensure the fully functional pest surveillance and management system it has put in place is sustainable beyond the project’s life.

*CIMMYT researchers Dave Hodson (left) and Francis Mwatuni (center) discuss MLN issues with another delegate during the 3-year MLN project review workshop. (Photo: Joshua Masinde/CIMMYT)*

Screening cycle for deadly MLN virus set to begin in Kenya during July 2018

Written by on June 21, 2018. Posted in News.

The third installment of the 2018 maize lethal necrosis (MLN) phenotyping (screening/ indexing) cycle will be held in July 2018 at the MLN artificial inoculation screening site in Naivasha, Kenya. Interested organizations from both the private and public sectors are invited to send maize germplasm for screening.

This is the largest dedicated MLN screening facility in East Africa. Since its inception in 2013, the facility has evaluated more than 120,000 accessions (more than 210,000 rows of maize) from more than 15 multinational and national seed companies and national research programs.

Partners can now plan for annual MLN Phenotyping (Screening / Indexing) during 2018 with the below mentioned schedule. The improved and streamlined approach for MLN phenotyping should enable our partners to accelerate breeding programs to improve resistance for Maize MLN for sub-Saharan Africa.

Schedule for 2018 – annual phenotyping (Indexing / Screening).

When the seeds are available	Planting Period – Planned	MLN Screening / Indexing
December	Second Week of January	MLN Indexing
March	Second week of April	MLN Screening
June	Second Week of July	MLN Indexing
August	Second Week of September	MLN Screening
October	Second week of November	MLN Indexing

More information about the disease and resources for farmers can be found on CIMMYT’s MLN portal.

Please note that it can take up to six weeks to process imports and clear shipments.

For assistance in obtaining import permits and necessary logistics for the upcoming screening, please contact:

Dr. L.M. Suresh
Tel: +254 20 7224600 (direct)

Email: l.m.suresh@cgiar.org

CIMMYT–Kenya, ICRAF House
United Nations Avenue, Gigiri
P.O. Box 1041–00621
Nairobi, Kenya.

Breaking Ground: Scientist L.M. Suresh uses new technology to fight maize lethal necrosis disease in eastern Africa

Written by on August 3, 2017. Posted in Features.

EL BATAN, Mexico (CIMMYT) – Maize lethal necrosis (MLN) disease is putting maize production at risk in eastern Africa, escalating food insecurity in the region.

First reported in Kenya in 2011, it has subsequently spread rapidly to neighboring countries and has now been confirmed in six eastern African countries, including the Democratic Republic of Congo, Ethiopia, Rwanda, Tanzania and Uganda.

The disease, caused by a combination of the maize chlorotic mottle virus (MCMV) and sugarcane mosaic virus (SCMV), causes irreversible damage that kills maize plants before they can grow and yield grain. If a maize field is infected early in the cropping cycle, total yield losses may occur.

Scientist L.M. Suresh of the International Maize and Wheat Improvement Center (CIMMYT) plays a central role in efforts to keep the disease in check. He contributes significantly to the screening of maize germplasm against MLN/MCMV, and to the identification of maize hybrids with tolerance/resistance to the disease.

In 2013, CIMMYT and the Kenya Agricultural and Livestock Research Organization established an MLN screening facility in Naivasha, Kenya, northwest of the capital Nairobi. The center serves as a centralized platform for screening maize germplasm under artificial inoculation from CIMMYT as well as public and private sector partners.

Suresh joined CIMMYT in 2015 as maize pathologist for sub-Saharan Africa. He is also manager of the MLN screening facility. As almost all of the commercial maize varieties currently grown in eastern Africa are susceptible to MLN, it is crucial to identify and develop germplasm with tolerance/resistance to the disease.

His work involves identifying sources of resistance to MLN and its component viruses MCMV and SCMV, and he works closely with other scientists on the genetic basis of MLN resistance. In addition, he contributes to the identification of elite maize hybrids that offer tolerance/resistance to MLN.

The use of advanced phenotyping technology makes it possible to quickly make physical observations of the plants on a large scale without painstaking manual scoring.

Another major component of Suresh’s work focuses on epidemiological factors related to MLN disease transmission, particularly seed transmission of MLN-causing viruses.

While focusing on MLN, he also works on other foliar – or leaf – diseases that are a threat to maize. As manager of the MLN screening facility, Suresh is responsible for the screening and indexing of about 84,000 rows of maize trials each year in three to four planting cycles at the Naivasha facility.

As of 2016, nearly 100,000 germplasm entries have been screened against MLN. To date, nine first generation MLN-tolerant elite maize hybrids have been released in East Africa. Several second-generation, CIMMYT-derived, MLN-resistant hybrids are currently being tested under national performance trials in Kenya, Tanzania and Uganda.

Born in Madasuru-Lingadahalli, a rural village in southern India, Suresh grew up on a farm where he worked in the fields during school holidays helping with weeding, picking areca nuts and harvesting.

In the 1970s and 1980s, his father was recognized by the State Department of Agriculture as a “progressive farmer” for undertaking various innovative approaches to increase rice paddy yields. However, the family continued to face several challenges, including low yielding varieties, diseases, pests, water scarcity and volatile prices.

To try and overcome some of these hardships, Suresh decided to further his education in agriculture.

“I believe that a deeper knowledge of science might offer alternatives, and that we should explore these options to help smallholder farmers like my father get better yields without increasing costs,” Suresh said. “My family always supported me to pursue higher education in the field of agriculture.”

Suresh earned undergraduate and master’s degrees at the University of Agricultural Sciences in Bangalore. During that time, Professor and emeritus scientist Varagur Ganesan Malathi from the Indian Agricultural Research Institute was his mentor and guide, also supervising him while he completed his Ph.D. at Kuvempu University in Karnataka.

Before joining CIMMYT, Suresh worked for 19 years at seed companies, including 14 years for Monsanto in India, where he led a team of plant health scientists focusing on diseases in vegetables. Additionally, he supported teams working on maize and cotton to harmonize various disease screening protocols.

“Working in agriculture gives me the best opportunity to contribute to efforts to help smallholder farmers improve their livelihoods,” Suresh said. “CIMMYT is a place full of scientific rigor and experts who work collaboratively with partners and thus bring impact. A major disease like MLN brings researchers from various organizations and institutions from different parts of the world together to accelerate efforts to not only understand the disease and establish effective surveillance, but also to engage stakeholders to commercially scale up disease-resistant hybrids developed by CIMMYT.”

The MLN web information portal, to which Suresh contributes, provides comprehensive information on various initiatives to tackle the MLN challenge. This website and information management system was developed with the objective of providing a one-stop resource for all the relevant information on MLN to interested stakeholders.

Artificial inoculation of maize germplasm at the Naivasha MLN screening site, Kenya. (Photo: B.Wawa/CIMMYT)

New online portal offers information to curb maize lethal necrosis in Africa

Written by on July 24, 2017. Posted in News.

The new maize lethal necrosis (MLN) online portal provides up-to-date information and surveillance tools to help researchers control and stop the spread of the deadly disease.

MLN was first reported in Kenya in 2011 and has since then been reported in several countries in eastern Africa, especially the Democratic Republic of the Congo, Ethiopia, Kenya, Rwanda, Tanzania and Uganda. The disease kills plants before they can grow, and the pathogens are transmitted by insects or contaminated seed. Serious damage to the region’s maize production from MLN has impacted household food security.

The online portal, found at mln.cimmyt.org, details the spread of MLN, where the disease has been managed and controlled, and how to identify it in the field. It also provides key MLN publications, surveillance software, MLN incidence maps, information on the MLN Screening Facility, and MLN-tolerant hybrids that are either released or in pipeline.

One tool on the portal is the MLN surveillance and monitoring system that provides real-time data to identify the presence and spread of the disease across five endemic countries in eastern Africa, and three selected non-endemic countries in southern Africa. The system was developed by scientists collaborating with the International Maize and Wheat Improvement Center (CIMMYT), with support from the United States Agency for International Development (USAID).

In 2016, MLN surveillance was successfully conducted in Malawi, Zambia and Zimbabwe – three major seed producing countries in Africa – and the data is presented in the portal, detailing MLN’s status across 652 surveyed maize fields. Future data gathered in other affected countries will also be uploaded to the portal as surveillance teams conduct fieldwork using Global Positioning System online survey tools, to assess the spread and severity of the disease in these countries. Ongoing surveillance in endemic countries allows stakeholders to see real-time updates on the spread of MLN.

MLN susceptible hybrids compared to a CIMMYT-derived MLN-tolerant hybrid. Photo: CIMMYT

Since the disease was first reported, collaborative efforts have resulted in the establishment of a MLN Screening Facility at the Kenya Agricultural & Livestock Research Organization (KALRO) center at Naivasha in 2013. The facility, managed by CIMMYT, has so far screened nearly 100,000 maize germplasm entries — 56 percent from CIMMYT — against MLN under artificial inoculation over the last four years.

Nine CIMMYT-derived MLN-tolerant hybrids have been already released in three countries – seven in Kenya, one in Uganda and one in Tanzania. Eleven second generation hybrids are currently in national performance trials in these countries. Intensive efforts are currently being made by seed companies in Kenya, Tanzania and Uganda to expand the delivery of MLN-tolerant maize seed to the smallholders.

The MLN portal enables researchers to comprehensively assess the situation with regard to MLN, helps strengthen the national disease monitoring and diagnostic systems by providing faster and accurate data, and offers access to CIMMYT-offered MLN phenotyping services.

Three major commercial maize seed exporting countries in southern Africa found free from maize lethal necrosis

Written by on November 25, 2016. Posted in News.

brenda_2 — Maimouna Abass, a plant health inspector at Zambia Agriculture Research Institute collects leave samples to test for MCMV in a practical session during the MLN surveillance and diagnostic workshop held in Harare, Zimbabwe. Photo: D. Hodson/CIMMYT

NAIROBI, Kenya (CIMMYT) – Three major commercial maize-growing and seed exporting countries in southern Africa were found to be so far free from the deadly maize lethal necrosis (MLN) disease. MLN surveillance efforts undertaken by national plant protection organizations (NPPOs) in Malawi, Zambia and Zimbabwe in 2016 have so far revealed no incidence of MLN, including the most important causative agent, maize chlorotic mottle virus (MCMV).

The three countries export an estimated 7,000 metric tons of maize seed to Angola, Botswana, Democratic Republic of Congo, Ethiopia, Kenya, Malawi, Mozambique, Rwanda, Swaziland and Tanzania for commercial cultivation by millions of smallholder farmers whose households rely on maize as a staple food.

MLN surveys were conducted as part of ongoing efforts through a project on MLN Diagnostics and Management, funded by U.S. Department for International Development (USAID) East Africa Mission, to strengthen the capacity of NPPOs on surveillance and diagnostics. A total of 12 officers were equipped with knowledge on modern sampling and diagnostics techniques to test plants and seed lots for MLN causing viruses; this was done through a training workshop held in Harare, Zimbabwe on March 3 and 4, 2016 facilitated by scientists working with the International Maize and Wheat Improvement Center (CIMMYT).

The NPPO teams from Malawi, Zambia and Zimbabwe then undertook surveys of farmers’ and commercial maize seed production fields, including testing (through MCMV immunostrips) for possible presence of the virus.

“When CIMMYT called the first stakeholders awareness meeting we realised we needed to do this surveillance as soon as possible to ascertain MLN status in the country – and so the training was very important and extremely useful,” said Maimouna Abass, a plant health inspector at Zambia Agriculture Research Institute (ZARI). “The fact that we went to the field and successfully conducted the surveys using the MLN diagnostics and sampling techniques learnt was great.”

Abass and three colleagues who participated in the training, trained 10 other inspectors who took part in the surveillance work.

The results from farmers’ fields, commercial seed production fields and agri-seed dealers, showed negative results for the presence of MCMV and MLN. The MLN surveillance techniques and protocols used across all the three countries were similar, making it possible to effectively compare the results.

“The harmonization of the protocols, across the teams from Malawi and Zambia, was important for me, since this meant that the three countries were able to do the same surveillance using the same protocols and applying the same design across all the countries,” said Nhamo Mudada, chief research officer from the Plant Quarantine Station in Zimbabwe.

Participants recieve instructions from L.M Suresh, a maize pathologist at CIMMYT, during the MLN surveillance and diagnostic workshop. Photo: D.Hodson/CIMMYT

Although the MLN disease has not been detected in the southern Africa region, the risk of incidence still remains high through various means, including insect vectors, contaminated seed, and cross-border grain transfers. Therefore, continued caution and stringent surveillance, monitoring and diagnostic measures are required to prevent the possible incidence and spread of MLN into the non-endemic countries.

Further surveillance work will be conducted in 2017, so that each team can cover other targeted areas within their respective countries. MLN surveillance using harmonized protocols will also be undertaken in the MLN-endemic countries, namely Ethiopia, Kenya, Rwanda, Tanzania and Uganda. Through systematic surveillance efforts, NPPOs, seed companies and policymakers can clearly understand the prevalence of MLN in specific areas in an endemic country for targeted management. Also, seed companies will be able to target production of commercial seed in MLN-free areas.

As this work progresses, B. M. Prasanna, director of the CGIAR Research Program on MAIZE and CIMMYT’s Global Maize Program as well as Leader for the MLN Diagnostics and Management Project, emphasized the need to intensively deploy MLN-tolerant and resistant varieties, not only in the MLN-endemic countries in eastern Africa, but also in the non-endemic countries in sub-Saharan Africa.

“We have about 22 new, high-yielding, MLN-tolerant or resistant hybridsthat are presently under national performance trials in Kenya, Tanzania and Uganda. We actively encourage seed companies operating in southern Africa to take up promising pre-commercial hybrids with MLN tolerance or resistance from CIMMYT, for release, scale up and deployment to the farmers,” Prasanna said. “Diagnostics and surveillance have to go hand in hand with deployment of new improved varieties that can effectively respond to the MLN challenge.”

In the East African countries of Kenya, Tanzania and Uganda, seed companies have already released MLN-tolerant varieties. While one hybrid is already being commercialized in Uganda, three more are expected to reach farmers in Kenya and Tanzania from 2017.

“There is also now a very urgent need to deploy MLN resistant varieties in Rwanda and Ethiopia. We need to convey this message to the government and seed companies and work closely to get the seed of MLN resistant varieties to the farmers as soon as possible,” Prasanna added.

The MLN diagnostics and management project, which is funded by the U.S. Department for International Development (USAID), supports work aimed at preventing the spread of MCMV from MLN-endemic to non-endemic areas in sub-Saharan Africa. USAID also supports the commercial seed sector and phytosanitary systems in targeted countries (Ethiopia, Kenya, Malawi, Rwanda, Tanzania, Uganda, Zambia and Zimbabwe), in the production of MCMV-free commercial seed, and promotes the use of clean hybrid seed by the farmers.

Combating spread of MLN in Africa poses unique but surmountable challenges, seed health specialist says

Written by on November 14, 2016. Posted in Features.

Anne Wangui, a seed health technician at CIMMYT demonstrate DAS–ELISA method used for detecting MLN-causing viruses. B.Wawa/CIMMYT

NAIROBI, Kenya (CIMMYT) – The maize lethal necrosis (MLN) disease poses a major concern to researchers, seed companies and farmers in sub-Saharan Africa. The impact of MLN is massive in the affected countries, especially at the household level for smallholder farmers who can experience up to 100 percent yield loss.

Concerted regional efforts through a project funded by the U.S. Agency for International Development (USAID) over the past year have helped in prioritizing and targeting efforts to stop the spread of the disease from the endemic to the non-endemic countries in sub-Saharan Africa. The project target countries are Ethiopia, Kenya, Rwanda, Tanzania and Uganda (currently MLN endemic), while Malawi, Zambia and Zimbabwe are MLN non-endemic but important commercial maize seed producing countries where the project implemented extensive MLN surveillance efforts.

Determining exactly how the MLN causing viruses, which include maize chlorotic mottle virus (MCMV) and sugarcane mosaic virus, are transmitted in the field through insect-vectors, infected plants and seed lots, has made diagnosis a key element in the efforts to halt the spread of the disease. If the viruses, in particular MCMV, the major causative agent, are introduced into a new area through contaminated seed and infected plants and not diagnosed and destroyed immediately, MLN can spread rapidly. Insect vectors in the field can play a significant role in transmitting viruses to the neighboring healthy maize fields.

In order to manage MLN at a regional level, partners in the project are developing harmonized diagnostic protocols to test, detect and prevent its spread through available mitigation measures. These were highlighted during the MLN Diagnostics and Management Project Review and Planning Meeting held in October, 2016 in Nairobi.

Monica Mezzalama, head of the CIMMYT Seed Health Laboratory in Mexico and a plant pathologist, shared her views on MLN testing and diagnostic methods that can be adopted to test maize plants and seed lots in the following interview.

Q: What is the role of diagnostics in managing MLN in Africa?

A: The role of sensitive, reliable, reproducible, affordable and standardized diagnostic tools is fundamental to the management of MLN in Africa. Only with an appropriate diagnosis tool, we can effectively detect and prevent further dispersal of the disease to the non-endemic areas through seed.

Q: What is the progress for detecting MLN in seed lots?

A: At the moment, detection in seed lots is still a weak link in the MLN management chain, although detection methods are available, such as ELISA and several versions of PCR, which are serological and molecular based, respectively, for the detection of MLN viruses. Extracting the pathogen from seed is more difficult than extracting it from leaf tissue, making it more time consuming to obtain clear and reliable results. Additionally, scientists are on the verge of resolving the significant issue of “sampling intensity,” which refers to the proportion of the seed sampled from the presented seed lots.

Q: What are some of the practices CIMMYT has adopted to ensure MLN-free seed production across regional centers in Africa?

A: Since 2013, CIMMYT has implemented several effective measures to ensure healthy MLN-free seed production and exchange. An aggressive strategy against the disease has been adopted at the main maize breeding station at Kenya Agricultural Livestock and Research Organization in Kiboko, by introducing a maize-free period of two months annually on the station as well as in the surrounding areas in close interaction with the farming communities in the neighboring villages. All this was possible thanks to the great collaboration between KALRO staff, CIMMYT colleagues, and the local farmers. This action taken for two consecutive years reduced drastically the incidence of MLN infected plants. In addition, a very thoughtful sensitization campaign was carried out, explaining how to effectively apply insecticide to control vectors, how to avoid the spread of the pathogen from one field to another by advising workers to change their clothes and shoes after working in an infected field. Also, management of planting dates has been implemented to avoid peaks of vectors populations or physically avoiding the arrival of the insects by planting according to the wind stream direction. In Zimbabwe, CIMMYT has also invested significant resources by establishing an MLN Quarantine Facility at Mazowe, near Harare to enable safe exchange of MLN virus-free breeding materials in southern Africa.

Q: Based on your experience with various diagnostic tools, what options would work for Africa’s seed companies and regulatory agencies to help detect MLN-causing viruses?

A: For detection of MLN viruses in green leaf tissue, I think immunostrips, ELISA and PCR techniques work very well and they can be adopted according to the level of specialization of the operator, infrastructure and financial resources available. As far as detection in dry seed is concerned, I think that at the moment the ELISA technique is the most reliable and affordable. PCR methods are available, but still some improvement needs to be done in the extraction of the viral RNA from the seed matrix.

Q: What factors do the relevant actors need to consider in the process of harmonizing diagnostic protocols across MLN-endemic and non-endemic countries?

A: Harmonization of protocols and procedures are needed not only for MLN, but also for effective design and implementation of phytosanitary aspects related to the exchange of commercial seed and vegetative material across borders. Unfortunately, it is not an easy task because of the number of actors involved, including national plant protection organizations, seed companies, seed traders, farmers, and policy makers. Nevertheless, the most important factors that, in my opinion, should be taken into consideration for consensus on harmonized protocols and where the efforts should focus on are: avoid the spread of the disease from country to country, and from the endemic to non-endemic areas within the same country; implement a well-coordinated and integrated package of practices for effective management of MLN in the endemic countries; reduce as much as possible economic losses due to the restriction on seed exchange; implement serious and effective seed testing and field inspections of the seed multiplication plots to prevent the incidence of MLN and for timely detection and elimination of infected plants.

View Meeting presentations here

MLN Pathogen Diagnosis, MLN-free Seed Production and Safe Exchange to Non-Endemic Countries Brochure

Visit the MLN website for more information

The CIMMYT-led MLN Diagnostics and Management Project, funded by USAID East Africa Mission is coordinating the above work with objectives to: a) prevent the spread of MLN, especially Maize Chlorotic Mottle Virus (MCMV), from the MLN-endemic countries in eastern Africa to non-endemic countries in sub-Saharan Africa; b) support the commercial seed sector in the MLN-endemic countries in producing MCMV-free commercial seed and promote the use of clean hybrid seed by the farmers; and c) to establish and operate a MLN Phytosanitary Community of Practice in Africa, for sharing of learning, MLN diagnostic and surveillance protocols, and best management practices for MLN control in Africa.

MLN diagnostics and management in Africa through multi-institutional synergies

Written by on May 9, 2015. Posted in News.

Maize Lethal Necrosis (MLN) disease has continued to wreak havoc on maize production in East Africa since it was first reported in Kenya in 2011, and since then reported in the Democratic Republic of the Congo, Ethiopia, Rwanda, Tanzania, South Sudan and Uganda. The disease, caused by a combination of the Maize Chlorotic Mottle Virus (MCMV) and Sugarcane Mosaic Virus (SCMV), causes irreversible damage that kills maize plants before they can grow and yield grain. MLN pathogens can be transmitted not only by insect vectors but also through contaminated seed. The epidemic is exacerbated by lack of MLN-resistant maize varieties and year round cultivation of maize in many areas in eastern Africa, enabling the build-up of virus inoculum and allowing transmission via insect vectors. For this reason, CIMMYT scientists Monica Mezzalama, Biswanath Das, and B.M. Prasanna have developed a brochure “MLN Pathogen Diagnosis, MLN-free Seed Production and Safe Exchange to Non-Endemic Countries” for providing important information on these key areas to stakeholders, especially seed companies and regulatory agencies operating in both MLN-affected as well as MLN non-endemic countries.

“MLN is an increasing regional threat to food security in sub-Saharan Africa, and must be tackled with concerted effort from all actors in order to safeguard the maize seed sector and protect the livelihoods of smallholder farmers,” said Prasanna. The brochure proposes several key steps to curb the spread of MLN, through MLN diagnostics, production of MLN-free seed, and safe exchange to MLN-endemic countries. The brochure also advises on appropriate agronomic practices that can prevent disease incidence in seed production fields.

An International Conference on “MLN Diagnostics and Management in Africa” will be organized jointly by AGRA (Alliance for Green Revolution in Africa) and CIMMYT during 12-14 May in Nairobi, Kenya, in order to review the present status of MLN incidence and impacts in sub-Saharan Africa (SSA), controlling seed transmission of MLN, managing seed production in MLN-endemic countries, creating awareness about MLN diagnostic protocols, and identifying ways to strengthen MLN diagnostics capacity in SSA, among other topics.

Stepping up the fight against maize lethal necrosis in Eastern Africa

Written by on August 1, 2013. Posted in News.

MLN-Eastern-Africa1 “I can now identify with accuracy plants affected with maize lethal necrotic disease,” stated Regina Tende, PhD student attached to CIMMYT, after attending the CIMMYT-Kenya Agricultural Research Institute (KARI) “Identification and Management of Maize Lethal Necrosis” workshop in Narok, Kenya, during 30 June-3 July 2013. This was not the case a few weeks ago when Tende, who is also a senior research officer at KARI-Katumani, received leaf samples from a farmer for maize lethal necrosis (MLN) verification.

Tende is one of many scientists and technicians who experienced difficulty in differentiating MLN from other diseases or abiotic stresses with similar symptoms. According to Stephen Mugo, CIMMYT Global Maize Program (GMP) principal scientist and organizer of the workshop, this difficulty encouraged CIMMYT and KARI to organize this event to raise awareness about MLN among scientists, technicians, and skilled field staff; provide training on MLN diagnosis especially at field nurseries, trials, and seed production fields; train on MLN severity scoring to improve the quality of data generation in screening trials; and introduce MLN management in field screening sites to scientists, technicians, and skilled staff. The workshop brought together over 80 scientists and technicians from CIMMYT, KARI, and other national agricultural research systems (NARS) partners from Tanzania, Uganda, Rwanda, and Zimbabwe.

“It is important that all the people on the ground, particularly the technicians who interact daily with the plants and supervise research activities at the stations, understand the disease, are able to systematically scout for it, and have the ability to spot it out from similar symptomatic diseases and conditions like nutrient deficiency,” stated GMP director B.M. Prasanna.

Proper and timely identification of the MLN disease, which is a pre-requisite for effective control, is not easy. CIMMYT maize breeder Biswanath Das explains: “First of all, the disease is caused by a combination of two viruses, Maize chlorotic mottle virus (MCMV) and Sugarcane mosaic virus (SCMV). Secondly, its symptoms –severe mottling of leaves, dead heart, stunted growth (shortened internode distance), leaf necrosis, sterility, poor seed set, shriveled seeds– are not always unique to MLN but could be due to other fungal diseases and abiotic conditions.” The training workshop was one of CIMMYT/KARI initiatives to combat the disease threatening all the gains made so far in maize breeding. “With nearly 99% of the commercial maize varieties so far released in Kenya being susceptible to MLN, it is important that institutions like CIMMYT and KARI, in strong collaboration with the seed sector, develop and deploy MLN disease resistant varieties in an accelerated manner,” stated Prasanna. One of the key initiatives in this fight is the establishment of a centralized MLN screening facility under artificial inoculation for Eastern Africa at the KARI Livestock Research Farm in Naivasha. Plans are also underway to establish a network of MLN testing sites (under natural disease pressure) in the region to evaluate promising materials from artificial inoculation trials in Naivasha. The state of the art maize doubled haploid (DH) facility currently under construction in Kiboko will also play a crucial role in accelerating MLN resistant germplasm development. “The DH technology, in combination with molecular markers, can help reduce by half the time taken for developing MLN resistant versions of existing elite susceptible lines,” stated Prasanna.

MLN-Eastern-Africa2 During his opening speech, Joseph Ng’etich, deputy director of Crop Protection, Ministry of Agriculture, noted that about 26,000 hectares of maize in Kenya were affected in 2012, resulting in an estimated loss of 56,730 tons, valued at approximately US$ 23.5 million. Seed producers also lost significant acreages of pre-basic seed in 2012: Agriseed lost 10 acres in Narok; Kenya Seed lost 75; and Monsanto 20 at Migtyo farm in Baringo, according to Dickson Ligeyo, KARI senior research officer and head of Maize Working Group in Kenya.

While this loss represents only 1.7%, Ligeyo assured everyone that Kenya is not taking any chances and has come up with a raft of measures and recommendations: farmers in areas where rainfall is all year round or maize is produced under irrigation are advised to plant maize only once a year; local quarantine has been enforced and farmers are to remove all infected materials from the fields and stop all movement of green maize from affected to non-affected areas; seed companies must ensure that seeds are treated with appropriate seed dressers at recommended rates, they must also promote good agricultural practices, crop diversification, and rotation with non-cereal crops.

Throughout the workshop, participants learned about theoretical aspects of MLN, such as the disease dynamics, management of MLN trials and nurseries, and identification of germplasm for resistance to MLN. They also participated in practical sessions on artificial inoculation, and identification and scoring. Several CIMMYT scientists played an active role in organizing the workshop, including breeders Stephen Mugo, Biswanath Das, Yoseph Beyene, and Lewis Machida; entomologist Tadele Tefera; and seed systems specialist Mosisa Regasa. They were accompanied by KARI scientist Bramwel Wanjala, KEPHIS regulatory officer Florence Munguti, and NARS maize research leaders Claver Ngaboyisonga (Rwanda), Dickson Ligeyo (Kenya), Julius Serumaga (Uganda), and Kheri Kitenge (Tanzania). During his closing remarks, KARI Food Crops program officer Raphael Ngigi, on behalf of KARI director, urged participants to rigorously implement what they had learnt during the workshop in their respective countries or Kenya regions to help combat MLN at both research farms and farmers’ fields.

Commenting on the usefulness of the workshop, technical officer at KARI-Embu Fred Manyara stated: “I will no longer say I do not know or I am not sure, when confronted by a farmer’s question on MLN.”

Promising CIMMYT maize inbreds and pre-commercial hybrids identified against maize lethal necrosis (MLN)

Written by on June 14, 2013. Posted in News.

The maize lethal necrosis (MLN) disease first appeared in Kenya’s Rift Valley in 2011 and quickly spread to other parts of Kenya, as well as to Uganda and Tanzania. Caused by a synergistic interplay of maize chlorotic mottle virus (MCMV) and any of the cereal viruses in the family, Potyviridae, such as Sugarcane mosaic virus (SCMV), Maize dwarf mosaic virus (MDMV), or Wheat streak mosaic virus (WSMV), MLN can cause total crop loss if not controlled effectively.

A regional workshop on MLN and the control strategies was organized by CIMMYT and KARI during February 12-14, 2013 in Nairobi, which was attended by some 70 scientists, seed company breeders and managers, and representatives of ministries of agriculture and regulatory authorities in Kenya, Uganda, Tanzania, and the USA. The Workshop led to identification of important action points steps for effectively controlling the disease.

CIMMYT scientists have been working closely with virology experts from USDA-ARS and Kenya Agricultural Research Institute (KARI) to develop suitable protocols for testing the responses of maize germplasm against MLN, and to identify promising inbred lines and hybrids with resistance to MLN. During the 2012-2013 crop season, the CIMMYT-KARI team undertook extensive screening of inbred lines, pre-commercial and commercial hybrids in Naivasha and Narok in Kenya, under high natural disease pressure and artificial inoculation, respectively.

A trial featuring 119 commercial maize varieties (released in Kenya) under artificial inoculation during 2012-2013 revealed that as many as 117 varieties were susceptible to MLN. Another set of trials including 335 elite inbred lines, 366 pre-commercial hybrids and 7 commercial hybrids (as checks) under MLN artificial inoculation in Narok, and another set of trials comprising 350 elite inbred lines and 135 pre-commercial hybrids under natural disease pressure in Naivasha, led to identification of some promising CIMMYT inbred lines as well as pre-commercial hybrids showing resistance or moderate resistance. These results offer considerable hope to combat, through breeding efforts, the deadly MLN disease that has severely affected maize harvests and discouraged farmers from growing maize in eastern Africa.

Notes on trial results

The details of the promising CIMMYT elite inbred lines and pre-commercial hybrids against MLN are presented in Table 1 and Table 2, respectively. The results presented in Table 1 are based on evaluation of CIMMYT inbred lines in four independent trials, two under artificial inoculation (Narok) and two under natural disease pressure (Naivasha) during 2012-2013. In each trial, entries were replicated (minimum two), and MLN severity scores (on a 1-5 scale basis) were recorded three or more times during the crop cycle, from the vegetative to the reproductive stage. The highest average MLN severity score (max. MLN score), recorded at any stage during the trial, is presented as representative of a given entry.

The data must be critically assessed and cautiously used by stakeholders and partners. More weight should be given to data from artificially inoculated trials, since trials under natural disease pressure are more liable to ‘disease escapes’ and identification of false positives. Caution must be exercised when using specific lines identified as potentially resistant (R) or moderately resistant (MR), especially when classification is based on data from only one trial (even under artificial inoculation). Please note that in such cases, the responses of the lines need to be validated by CIMMYT through further trials.

CIMMYT is working closely with both public and private sector partners to significantly expand the MLN evaluation network capacity in eastern Africa, and will continue the intensive efforts to identify/develop and deliver new sources of resistance to MLN.

For further information on:
MLN research-for-development efforts undertaken by CIMMYT, please contact: Dr BM Prasanna, Director, Global Maize Program, CIMMYT, Nairobi, Kenya; Email: b.m.prasanna@cgiar.org.
Availability of seed material of the promising lines and pre-commercial hybrids, please contact: Dr Mosisa Regasa (m.regasa@cgiar.org) if your institution is based in eastern Africa, or Dr James Gethi (j.gethi@cgiar.org) if your institution is based in southern Africa or outside eastern and southern Africa.