Alinda Sarah shows a maize cob due for harvest on the farm she owns with her husband in Masindi, mid-western Uganda. (Photo: Joshua Masinde/CIMMYT)
The ultimate challenge for crop breeders is to increase genetic gain of a crop: literally, to increase the crop’s yield on farmers’ fields. Wheat and maize breeders from the International Maize and Wheat Improvement Center (CIMMYT) and partner institutions are working to achieve this in record time, developing new varieties tailored for farmers’ needs that are also pest- and disease-resistant, climate-resilient, and nutritious.
This work is part of the Accelerating Genetic Gain in Maize and Wheat for Improved Livelihoods (AGG) project. Among other methods, breeders are using state-of-the-art novel tools such as genomic selection to achieve this ambitious goal.
In genomic selection, breeders use information about a plant’s genetic makeup along with data on its visible and measurable traits, known as phenotypic data, to “train” a model to predict how a cross will turn out — information known as “genomic estimated breeding values (GEBV)” — without having to plant seeds, wait for them to grow, and physically measure their traits. In this way, they save time and costs by reducing the number of selection cycles.
However, research is still ongoing about the best way to use genomic selection that results in the most accurate predictions and ultimately reduces selection cycle time. A recent publication by CIMMYT scientist Sikiru Atanda and colleagues has identified an optimal genomic selection strategy that maximizes the efficiency of this novel technology. Although this research studied CIMMYT’s maize breeding programs, AGG scientists working on wheat genetic gain and zinc nutritional content see cross-crop impacts.
Shortening a lengthy process
In the typical breeding stages, breeders evaluate parental lines to create new crosses, and advance these lines through preliminary and elite yield trials. In the process, thousands of lines are sown, grown and analyzed, requiring considerable resources. In the traditional CIMMYT maize breeding scheme, for example, breeders conduct five stages of testing to identify parental lines for the next breeding cycle and develop high yielding hybrids that meet farmers’ needs.
In the current scheme using genomic selection, breeders phenotype 50% of a bi-parental population to predict the GEBVs of the remaining un-tested 50%. Though this reduces the cost of phenotyping, Atanda and his co-authors suggest it is not optimal because the breeder has to wait three to four months for the plant to grow before collecting the phenotypic data needed to calibrate the predictive model for the un-tested 50%.
Atanda and his colleagues’ findings specify how to calibrate a model based on existing historical phenotypic and genotypic data. They also offer a method for creating “experimental” sets to generate phenotypic information when the models don’t work due to low genetic connectedness between the new population and historical data.
This presents a way forward for breeders to accelerate the early yield testing stage based on genomic information, reduce the breeding cycle time and budget, and ultimately increase genetic gain.
Regional maize breeding coordinator for Africa Yoseph Beyene explained the leap forward this approach represents for CIMMYT’s maize breeding in Africa.
“For the last 5 years, CIMMYT’s African maize breeding program has applied genomic selection using the ‘test-half-and-predict-half’ strategy,” he said. “This has already reduced operational costs by 32% compared to the traditional phenotypic selection.”
“The prediction approach shown in this paper — using historical data alone to predict untested lines that go directly to stage-two trials — could reduce the breeding cycle by a year and save the cost of testcross formation and multi-location evaluation of stage-one testing. This research contributes to our efforts in the AGG project to mainstream genomic selection in all the product profiles.”
Effective for maize and wheat
Atanda, who now works on the use of novel breeding methods to enhance grain zinc content in CIMMYT’s wheat breeding program, believes these findings apply to wheat breeding as well.
“The implications of the research in maize are the same in wheat: accelerating early testing stage and reducing the breeding budget, which ultimately results in increasing genetic gain,” he said.
CIMMYT Global Wheat Program director Alison Bentley is optimistic about the crossover potential. “It is fantastic to welcome Atanda to the global wheat program, bringing skills in the use of quantitative genetic approaches,” she said. “The use of new breeding methods such as genomic selection is part of a portfolio of approaches we are using to accelerate breeding.”
CIMMYT’s wheat breeding relies heavily on a time-tested and validated method using managed environments to test lines for a range of growing environments — from drought to full irrigation, heat tolerance and more — in CIMMYT’s wheat experimental station in Ciudad Obregón, in Mexico’s state of Sonora.
According to CIMMYT senior scientist and wheat breeder Velu Govindan, using the approaches tested by Sikiru can make this even more efficient. As a specialist in biofortification — using traditional breeding techniques to develop crops with high levels of micronutrients — Govindan is taking the lead mainstreaming high zinc into all CIMMYT improved wheat varieties.
“This process could help us identify best lines to share with partners one year earlier — and it can be done for zinc content as easily as for grain yield.”
If this study seems like an excellent fit for the AGG project’s joint focus on accelerating genetic gain for both maize and wheat, that is no accident.
“The goal of the AGG project was the focus of my research,” Atanda said. “My study has shown that this goal is doable and achievable.”
Global thought leader, philanthropist and one of the International Maize and Wheat Improvement Center (CIMMYT) and CGIAR’s most vocal and generous supporters, Bill Gates, wrote a book about climate change and is now taking it around the world on a virtual book tour to share a message of urgency and hope.
With How to Avoid a Climate Disaster, Gates sets out a holistic and well-researched plan for how the world can get to zero greenhouse gas emissions in time to avoid a climate catastrophe. Part of this plan is to green everything from how we make things, move around, keep cool and stay warm, while also considering how we grow things and what can be done to innovate agriculture to lower its environmental impact.
Interviewed by actor and producer Rashida Jones, Gates explained his passion for action against climate change: “Avoiding a climate disaster will be one of the greatest challenges us humans have taken on. Greater than landing on the moon, greater than eradicating smallpox, even greater than putting a computer on every desk.”
“The world needs many breakthroughs. We need to get from 51 billion tons [of greenhouse gases] to zero while still meeting the planet’s basic needs. That means we need to transform the way we do almost everything.”
Bill Gates (left) talks to Rashida Jones during one of the events to present his new book.
Innovations in agriculture
When a book tour event attendee asked about the role of agriculture research in improving farmers’ livelihoods, Gates linked today’s challenge to that of the Green Revolution more than half a century ago. “There’s nothing more impactful to reduce the impacts of climate change than working on help for farmers. What we can do this time is even bigger than that. […] The most unfunded thing in this whole area is the seed research that has so much potential,” he said.
One such innovation and one of Gates’ favorite examples of CGIAR’s work is featured in Chapter 9 of his climate book – “Adapting to a warmer world” – and has been the source of generous funding from the Bill & Melinda Gates Foundation: drought-tolerant maize. “[…] as weather patterns have become more erratic, farmers are at greater risk of having smaller maize harvests, and sometimes no harvest at all. So, experts at CGIAR developed dozens of new maize varieties that could withstand drought conditions, each adapted to grow in specific regions of Africa. At first, many smallholder farmers were afraid to try new crop varieties. Understandably so. If you’re eking out a living, you won’t be eager to take a risk on seeds you’ve never planted before, because if they die, you have nothing to fall back on. But as experts worked with local farmers and seed dealers to explain the benefits of these new varieties, more and more people adopted them,” writes Gates.
We at CIMMYT are very proud and humbled by this mention as in collaboration with countless partners, CIMMYT and the International Institute of Tropical Agriculture (IITA) developed and promoted these varieties across 13 countries in sub-Saharan Africa and contributed to lifting millions of people above the poverty line across the continent.
For example, in Zimbabwe, farmers who used drought-tolerant maize varieties in dry years were able to harvest up to 600 kilograms more maize per hectare — enough for nine months for an average family of six — than farmers who sowed conventional varieties.
The world as we know it is over and, finally, humanity’s fight against climate change is becoming more and more mainstream. CIMMYT and its scientists, staff, partners and farmers across the globe are working hard to contribute to a transformation that responds to the climate challenge. We have a unique opportunity to make a difference. It is in this context that CGIAR has launched an ambitious new 10-year strategy that echoes Gates’s hopes for a better environment and food security for the generations to come. Let’s make sure that it ticks the boxes of smallholder farmers’ checklists.
Haploids — which are produced naturally in maize — were first identified in the crop about a century ago. Today they are used widely in different breeding programs, particularly in the development of doubled haploids, which are highly uniform, genetically pure and stable. Doubled-haploid technology has simplified logistics to make the maize breeding process more efficient and intuitive, facilitated studies at the molecular and genomic level, and increased genetic gains in different breeding programs.
In a recent review article, scientists from the International Maize and Wheat Improvement Center (CIMMYT) examine strategies for haploid induction and identification, chromosome doubling and production of doubled haploid seed through self-fertilization. They also discuss the potential applications and key challenges linked with doubled haploid technology in maize, and suggest future research directionsfor people involved in fast-track maize breeding, the seed industry, and academia.
Extensive studies of haploids and doubled haploids have increased our understanding of the genetic basis and mechanisms involved in haploid induction, the factors that affect haploid induction, different markers to identify putative haploids, and different chemicals agents that can be used for chromosome doubling.
The technology is useful because the resulting plants are free from different social issues and legal regulations associated with transgenic crops. It maximizes genetic gains in breeding programs, is one of the fastest tools available for developing large numbers of inbred lines quickly and reduces the cost of breeding programs.
“Deployment of doubled haploid technology is much needed for commercial hybrid maize breeding programs to make them more efficient and economical,” says article co-author Abdurahman Beshir, a maize seed systems specialist based in Nepal. “The technology is also useful to have accelerated varietal turnover and a higher maize seed replacement rate in different market segments.”
Many multinational seed companies have adopted doubled haploid technology for the wide-scale production of inbred lines. The development of novel techniques for haploid induction and the subsequent production of doubled haploid plants holds significant potential for the management of genetic resources, germplasm enhancement and the development of novel plant populations.Researchers at CIMMYT have also made significant efforts to help national breeding programs adopt this technology, especially in South Asia, where the organisation has shared haploid inducers with numerous partners in Pakistan.
But, while this technology can accelerate maize breeding, it still faces challenges at each step of doubled haploid line development and the authors argue there is a need to extensively explore the genetic potential of this technology to continue increasing the genetic gains associated with different breeding programs.
Cover image: A mixture ofdoubledhaploidmaizekernelsseen in close-up at CIMMYT’s Agua Fria experimental station in Mexico. (Photo: Alfonso Cortés/CIMMYT)
Read more new publications from CIMMYT researchers:
Nancy Wawira stands among ripening maize cobs of high yielding, drought-tolerant maize varieties on a demonstration farm in Embu County, Kenya. Involving young people like Wawira helps to accelerate the adoption of improved stress-tolerant maize varieties. (Photo: Joshua Masinde/CIMMYT)
Since the 1980s, the International Maize and Wheat Improvement Center (CIMMYT) and the International Institute of Tropical Agriculture (IITA) have spearheaded the development and deployment of climate-smart maize in Africa.
This game-changing work has generated massive impacts for smallholder farmers, maize consumers, and seed markets in the region. It also offers a blueprint for CGIAR’s new 2030 Research and Innovation Strategy, which proposes a systems transformation approach for food, land and water systems that puts climate change at the center of its mission.
Over the course of the 10-year run of the first iteration of this collaborative work on climate-adaptive maize, the Drought Tolerant Maize for Africa (DTMA) project, CIMMYT and IITA partnered with dozens of national, regional, and private sector partners throughout sub-Saharan Africa to release around 160 affordable maize varieties. This month, CGIAR recognizes climate-smart maize as one of the standout 50 innovations to have emerged from the institution’s first half-century of work.
Game changer
Maize’s importance as a food crop in sub-Saharan Africa is hard to overstate. So are the climate change-driven challenges it faces.
It accounts for almost one third of the region’s caloric intake. It is grown on over 38 million hectares, primarily under rainfed conditions. Around 40% of this area faces occasional drought stress. Another 25% suffers frequent drought and crop losses reaching 50%.
Drought-tolerant maize stabilized production under drought-stress conditions. Recent studies show that farmers growing drought-tolerant maize varieties in dry years produced over a half ton more maize per hectare than those growing conventional varieties — enough maize to support a family of six for nine months.
Such drastic results fed increased demand for improved, climate-adaptive maize seed in sub-Saharan Africa, thus strengthening local commercial seed markets and helping drought-tolerant maize varieties reach an increasing share of climate-vulnerable farmers.
Today, approximately 8.6 million farmers have benefitted from CIMMYT- and IITA-derived climate-adaptive maize varieties in sub-Saharan Africa. Millions have risen above the poverty line.
In addition to drought-tolerance, CIMMYT- and IITA-derived climate-adaptive maize varieties have been developed to tolerate multiple climate-driven stresses and to provide improved nutritional outcomes through biofortification with essential nutrients such as provitamin A and zinc.
The task ahead
In his recently published book, How to Avoid a Climate Catastrophe, Bill Gates says “no other organization has done more than CGIAR to ensure that families — especially the poorest — have nutritious food to eat. And no other organization is in a better position to create the innovations that will help poor farmers adapt to climate change in the years ahead.”
CGIAR’s new strategic orientation is an important step towards making good on that potential. CIMMYT and IITA’s longstanding work on climate-smart maize offers an important blueprint for the kinds of bold, comprehensive, and collaborative research for development initiatives such a strategy could empower.
As CIMMYT and IITA directors general Martin Kropff and Nteranya Sanginga note in a recent op-ed, “The global battle against climate change and all its interconnected impacts requires a multisectoral approach to formulate comprehensive responses.”
The food security and livelihoods of smallholder farming families in sub-Saharan Africa depend on maize production. The region accounts for up to two-thirds of global maize production, but is facing challenges related to extreme weather events, climate-induced stresses, pests and diseases, and deteriorating soil quality. These require swift interventions and innovations to safeguard maize yields and quality.
In this Q&A, we reflect on the results and impact of the long-term collaborative work on drought-tolerant maize innovations spearheaded by two CGIAR Research Centers: the International Maize and Wheat Improvement Center (CIMMYT) and International Institute of Tropical Agriculture (IITA). This innovative work has changed guises over the years, from the early work of the Drought Tolerant Maize for Africa (DTMA) and Drought Tolerant Maize for Africa Seed Scaling (DTMASS) projects through later iterations such as Stress Tolerant Maize for Africa (STMA) and the newest project, Accelerating Genetic Gains in Maize and Wheat (AGG).
In this Q&A, three leaders of this collaborative research reflect on the challenges their work has faced, the innovations and impact it has generated for smallholder farmers, and possible directions for future research. They are: B.M Prasanna, director of CIMMYT’s Global Maize Program and of the CGIAR Research Program on Maize (MAIZE); Abebe Menkir, a maize breeder and maize improvement lead at IITA; and Cosmos Magorokosho, project lead for AGG-Maize at CIMMYT.
Briefly describe the challenges confronting small-scale farmers prior to the introduction of drought-tolerant maize and how CIMMYT and IITA responded to these challenges?
B.M.P.: Maize is grown on over 38 million hectares in sub-Saharan Africa, accounting for 40% of cereal production in the region and providing at least 30% of the population’s total calorie intake. The crop is predominantly grown under rainfed conditions by resource-constrained smallholder farmers who often face erratic rainfall, poor soil fertility, increasing incidence of climatic extremes — especially drought and heat — and the threat of devastating diseases and insect pests.
Around 40% of maize-growing areas in sub-Saharan Africa face occasional drought stress with a yield loss of 10–25%. An additional 25% of the maize crop suffers frequent drought, with yield losses of up to 50%. Climate change is further exacerbating the situation, with devastating effects on the food security and livelihoods of the millions of smallholder farmers and their families who depend on maize in sub-Saharan Africa. Therefore, the improved maize varieties with drought tolerance, disease resistance and other farmer-preferred traits developed and deployed by CIMMYT and IITA over the last ten years in partnership with an array of national partners and seed companies across sub-Saharan Africa are critical in effectively tackling this major challenge.
A.M.: Consumption of maize as food varies considerably across sub-Saharan Africa, exceeding 100 kg per capita per year in many countries in southern Africa. In years when rainfall is adequate, virtually all maize consumed for food is grown in sub-Saharan Africa, with a minimal dependence on imported grain. Maize production, however, is highly variable from year to year due to the occurrence of drought and the dependence of national maize yields on seasonal rainfall. One consequence has been widespread famine occurring every five to ten years in sub-Saharan Africa, accompanied by large volumes of imported maize grain as food aid or direct imports.
This places a significant strain on resources of the World Food Programme and on national foreign exchange. It also disincentivizes local food production and may not prevent or address cyclical famine. It also leaves countries ill-equipped to address famine conditions in the period between the onset of the crisis and the arrival of food aid. Investment in local production, which would strengthen the resilience and self-sufficiency in food production of smallholder farming families, is a far better option to mitigate food shortages than relying on food aid and grain imports.
C.M.: Smallholder farmers in sub-Saharan Africa face innumerable natural and socioeconomic constraints. CIMMYT, in partnership with IITA and national agricultural research system partners, responded by developing and catalyzing the commercialization of new maize varieties that produce reasonable maize yields under unpredictable rainfall-dependent growing season.
Over the life of the partnership, more than 300 new climate-adaptive maize varieties were developed and released in more than 20 countries across sub-Saharan Africa where maize is a major staple food crop. Certified seed of over 100 stress-tolerant improved maize varieties have been produced by seed company partners, reaching more than 110,000 tons in 2019. The seeds of these drought-tolerant maize varieties have benefited more than 8 million households and were estimated to be grown on more than 5 million hectares in eastern, southern and west Africa in 2020.
A farmer in Mozambique stands for a photograph next to her drought-tolerant maize harvest. (Photo: CIMMYT)
In what ways did the drought-tolerant maize innovation transform small-scale farmers’ ability to respond to climate-induced risks? Are there any additional impacts on small scale farmers in addition to climate adaptation?
B.M.P.: The elite drought-tolerant maize varieties can not only provide increased yield in drought-stressed crop seasons, they also offer much needed yield stability. This means better performance than non-drought-tolerant varieties in both good years and bad years to a smallholder farmer.
Drought-tolerant maize varieties developed by CIMMYT and IITA demonstrate at least 25-30% grain yield advantage over non-drought-tolerant maize varieties in sub-Saharan Africa under drought stress at flowering. This translates into at least a 1 ton per hectare enhanced grain yield on average, as well as reduced downside risk in terms of lost income, food insecurity and other risks associated with crop yield variability. In addition to climate adaptation, smallholder farmers benefit from these varieties due to improved resistance to major diseases like maize lethal necrosis and parasitic weeds like Striga. We have also developed drought-tolerant maize varieties with enhanced protein quality — such as Quality Protein Maize or QPM — and provitamin A, which improve nutritional outcomes.
We must also note that drought risk in sub-Saharan Africa has multiple and far-reaching consequences. It reduces incentives for smallholder farmers to intensify maize-based systems and for commercial seed companies to invest and evolve due to a limited seed market.
Drought-tolerant maize is, therefore, a game changer as it reduces the downside risk for both farmers and seed companies and increases demand for improved maize seed, thus strengthening the commercial seed market in sub-Saharan Africa. Extensive public-private partnerships around drought-tolerant maize varieties supported the nascent seed sector in sub-Saharan Africa and has enabled maize-based seed companies to significantly grow over the last decade. Seed companies in turn are investing in marketing drought-tolerant maize varieties and taking the products to scale.
A.M.: The DTMA and STMA projects were jointly implemented by CIMMYT and IITA in partnership with diverse national and private sector partners in major maize producing countries in eastern, southern and western Africa to develop and deploy multiple stress-tolerant and productive maize varieties to help farmers adapt to recurrent droughts and other stresses including climate change.
These projects catalyzed the release and commercialization of numerous stress-resilient new maize varieties in target countries across Africa. Increasing the resilience of farming systems means that smallholder farmers need guaranteed access to good quality stress resilient maize seeds. To this end, the two projects worked with public and private sector partners to produce large quantities of certified seeds with a continual supply of breeder seeds from CIMMYT and IITA. The availability of considerable amount of certified seeds of resilient maize varieties has enabled partners to reach farmers producing maize under stressful conditions, thus contributing to the mitigation of food shortages that affect poor people the most in both rural and urban areas.
C.M.: The drought-tolerant maize innovation stabilized maize production under drought stress conditions in sub-Saharan Africa countries. Recent study results showed that households that grew drought-tolerant maize varieties had at least half a ton more maize harvest than the households that did not grow the drought-tolerant maize varieties, thus curbing food insecurity while simultaneously increasing farmers’ economic benefits. Besides the benefit from drought-tolerant innovation, the new maize varieties developed through the partnership also stabilized farmers’ yields under major diseases, Striga infestation, and poor soil fertility prevalent in sub-Saharan Africa.
How is the project addressing emerging challenges in breeding for drought-tolerant maize and what opportunities are available to address these challenges in the future?
Margaret holds an improved ear of drought-tolerant maize. Margaret’s grandmother participated in an on-farm trial in Murewa district, 75 kilometers northeast of Zimbabwe’s capital Harare. (Photo: Jill Cairns/CIMMYT)
B.M.P.: A strong pipeline of elite, multiple-stress-tolerant maize varieties — combining other relevant adaptive and farmer-preferred traits — has been built in sub-Saharan Africa through a strong germplasm base, partnerships with national research partners and small- and medium-sized seed companies, an extensive phenotyping and multi-location testing network, and engagement with farming communities through regional on-farm trials for the identification of relevant farmer-preferred products.
CGIAR maize breeding in sub-Saharan Africa continues to evolve in order to more effectively and efficiently create value for the farmers we serve. We are now intensively working on several areas: (a) increasing genetic gains (both on-station and on-farm) through maize breeding in the stress-prone environments of sub-Saharan Africa by optimizing our breeding pipelines and effectively integrating novel tools, technologies and strategies (e.g., doubled haploids, genomics-assisted breeding, high-throughput and precise phenotyping, improved breeding data management system, etc.); (b) targeted replacement of old or obsolete maize varieties in sub-Saharan Africa with climate-adaptive and new varieties; (c) developing next-generation climate-adaptive maize varieties with traits such as native genetic resistance to fall armyworm, and introgressed nutritional quality traits (e.g., provitamin A, high Zinc) to make a positive impact on the nutritional well-being of consumers; and (d) further strengthening the breeding capacity of national partners and small and medium-sized seed companies in sub-Saharan Africa for a sustainable way forward.
A.M.: The DTMA and STMA projects established effective product pipelines integrating cutting-edge phenotyping and molecular tools to develop stress-resilient maize varieties that are also resistant or tolerant to MLN disease and fall armyworm. These new varieties are awaiting release and commercialization. Increased investment in strengthening public and private sector partnerships is needed to speed up the uptake and commercialization of new multiple stress-resilient maize varieties that can replace the old ones in farmers’ fields and help achieve higher yield gains.
Farmers’ access to new multiple-stress-tolerant maize varieties will have a significant impact on productivity at the farm level. This will largely be due to new varieties’ improved response to fertilizer and favorable growing environments as well as their resilience to stressful production conditions. Studies show that the adoption of drought-tolerant maize varieties increased maize productivity, reduced exposure to farming risk among adopters and led to a decline in poverty among adopters. The availability of enough grain from highly productive and stress-resilient maize varieties can be the cheapest source of food and release land to expand the cultivation of other crops to facilitate increased access to diversified and healthy diets.
C.M.: The project is tackling emerging challenges posed by new diseases and pests by building upon the successful genetic base of drought-tolerant maize. This is being done by breeding new varieties that add tolerance to the emerging disease and pest challenges onto the existing drought-tolerant maize backgrounds. Successes have already been registered in breeding new varieties that have high levels of resistance to MLN disease and the fall armyworm pest.
Opportunities are also available to address new challenges including: pre-emptively breeding for threats to maize production challenges that exist in other regions of the world before these threats reach sub-Saharan Africa; enhancing the capacity of national partners to build strong breeding programs that can address new threats once they emerge in sub-Saharan Africa; and sharing knowledge and novel high-value breeding materials across different geographies to immediately address new threats once they emerge.
Cover photo: Alice Nasiyimu stands in front of a drought-tolerant maize plot at her family farm in Bungoma County, in western Kenya. (Photo: Joshua Masinde/CIMMYT)
In an op-ed, Martin Kropff, Director General of CIMMYT, and Nteranya Sanginga, Director General of the International Institute of Tropical Agriculture (IITA), discuss how higher-yielding, stress-tolerant maize varieties can not only help smallholder farmers combat climatic variabilities and diseases, but also effectively diversify their farms.
A maize ear harvested from a “milpa,” the maize-based intercrop that is a critical source of food and nutritional security for smallholder farming communities in remote areas such as the Western Highlands of Guatemala. (Photo: Cristian Reyna)
The traditional milpa intercrop — in which maize is grown together with beans, squash, or other vegetable crops — can furnish a vital supply of food and nutrients for marginalized, resource-poor communities in the Americas, according to a study published today in Nature Scientific Reports.
One hectare of a milpa comprising maize, common beans, and potatoes can provide the annual carbohydrate needs of more than 13 adults, enough protein for nearly 10 adults, and adequate supplies of many vitamins and minerals, according to the study. The research was based on data from nearly 1,000 households across 59 villages of the Western Highlands of Guatemala and is the first to relate milpa intercropping diversity with nutritional capacity, using multiple plots and crop combinations.
“The milpa was the backbone of pre-Columbian agriculture in North America, Mexico, and Central America,” said Santiago López-Ridaura, specialist in agricultural systems and climate change adaptation at the International Maize and Wheat Improvement Center (CIMMYT) and lead author of the article.
“Milpa production anchored around locally-adapted maize is still an essential food and nutritional lifeline for isolated, often indigenous communities throughout Mexico and Central America, and can be tailored to improve their food and nutritional security, along with that of small-scale farmers in similar settings,” he added.
Maize for feed or food and nutrition?
In modern times, some 1 billion tons of maize are harvested yearly from about 200 million hectares worldwide. Much of this output results from intensive monocropping of hybrids that yield an average 10 tons per hectare, in places like the U.S.
This massive world harvest goes chiefly for animal feed, corn starch, corn syrup, ethanol, and myriad industrial products, but in sub-Saharan Africa, Latin America, and parts of Asia, maize remains a critical food staple, often grown by smallholder farmers with yields averaging around 1.5 tons per hectare.
The Western Highlands of Guatemala is among the world’s poorest regions — a mountainous area ill-served by markets and where communities battered by food insecurity and malnutrition sow crops at altitudes of up to 3,200 meters, according to Cristian A. Reyna-Ramírez, a co-author of the study from the Universidad Autónoma Metropolitana-Xochimilco, Mexico.
“Fully two-thirds of farmers in this region grow milpas based on maize but varying the intercrops with potatoes, faba bean, and even fruit trees,” Reyna-Ramírez said. “Our study showed that combinations such as maize-common bean-faba bean, maize-potatoes, and maize-common bean-potatoes provided the most carbohydrates, proteins, zinc, iron, calcium, potassium, folate, thiamin, riboflavin, vitamin B6, niacin and vitamin C.”
The classic “milpa” intercrop comprises maize, beans, and squash. The bean plant climbs the maize stalk to reach sunlight and its roots add nitrogen to the soil; the squash leaves shade the soil, conserving moisture and inhibiting weed growth. Milpa systems are often grown on steep hillsides at a wide range of altitudes. (Photo: Cristian Reyna)
Better diets and routes out of poverty?
With typical landholdings of less than a quarter hectare and households averaging six members, Guatemala’s Western Highlands inhabitants cannot depend on the milpa alone to satisfy their needs, López-Ridaura cautioned.
“As with many smallholder farm communities, lack of land and general marginalization traps them in a vicious circle of poverty and malnutrition, forcing them to experiment with risky cash crops or for working-age members to undertake dangerous and heartbreaking migrations to find work and send back remittances,” he explains.
According to López-Ridaura, this study points the way for tailoring milpa systems to help communities that still rely on that intercrop or others that could benefit from its use.
Looking forward
Natalia Palacios Rojas, CIMMYT maize quality and nutrition expert and a co-author of this article, notes that calculations of this and other milpa studies consider raw nutrients and that research is needed on the nutritional contributions of cooked food and non-milpa foods such as poultry, livestock, home-garden produce, and purchased food.
“Further work should also address the effects of storing milpa produce on its nutrient stability and how the seasonal availability of milpa crops impacts diets and nutrition,” Palacios said.
The authors are grateful for funding from the United States Agency for International Development (USAID) as part of Feed the Future, the U.S. Government’s global hunger and food security initiative, under the Buena Milpa project, as well as the support of the CGIAR Research Program on Maize.
The challenges facing our food system are growing, both in size and in complexity. In order to tackle these issues and meet the needs of our changing world, the International Maize and Wheat Improvement Center (CIMMYT) understands the importance of assembling a workforce that is diverse, creative and representative. In addition to encouraging STEM careers and hiring more women in scientific positions, we must also foster a more encouraging scientific community for women whose careers are just sparking.
Whether it is through a school field trip, a first internship or a PhD thesis project, CIMMYT is committed to encouraging young women to step into the lab and the fields, and up to the challenge, as we strive to create a more equitable community. On the International Day of Women and Girls in Science, we are inspired by the words of some of the many brilliant women whose scientific careers are just beginning, lighting the pathway to a more equitable future.
The International Day of Women and Girls in Science is particularly meaningful to CIMMYT’s new Global Wheat Program (GWP) Director, Alison Bentley. Listen and watch as she tells her story, from her first lightbulb moment on a high school field trip, to a leadership position in the wheat research world.
In celebration of the International Day of Women and Girls in Science, CIMMYT is participating in a unique marathon event, carrying a global conversation with CGIAR women scientists that are leading change and creating solutions to some of the world’s biggest challenges.
Powered by Women in Research and Science (WIRES), a new employee-led resource group at CGIAR, the event will showcase the many ways women scientists are transforming the way we look at our food, land and water systems around the world. In addition to learning about cutting-edge science, you’ll be able to engage with inspiring speakers in 13 different countries.
Join CIMMYT’s discussion on February 11, 2021, at 1:00 p.m. CST, and learn about the journeys of the 2020 Bänziger Award recipients, an engaging Q&A with four CIMMYT scientists, and our vision for a more equitable workforce. Register for the event.
The International Maize and Wheat Improvement Center (CIMMYT) is offering a new set of elite, improved maize hybrids to partners in eastern Africa and similar agro-ecological zones. National agricultural research systems (NARS) and seed companies are invited to apply for licenses to pursue national release of, and subsequently commercialize, these new hybrids, in order to bring the benefits of the improved seed to farming communities.
The deadline to submit applications to be considered during the first round of allocations is 9 February 2021. Applications received after that deadline will be considered during the following round of product allocations.
Information about the newly available CIMMYT maize hybrids from Eastern Africa breeding program, application instructions and other relevant material is available below.
To apply, please fill out the CIMMYT Improved Maize Product Allocation Application Forms, available for download at the links below. Each applicant will need to complete one copy of Form A for their organization, then for each hybrid being requested a separate copy of Form B. (Please be sure to use these current versions of the application forms.)
Researchers from the International Maize and Wheat Improvement Center (CIMMYT) and the International Livestock Research Institute (ILRI) have identified new genomic regions associated with maize stover quality, an important by-product of maize which can be used in animal feed.
The results of the study, published this month in Nature Scientific Reports, will allow maize breeders to select for stover quality traits more quickly and cost-effectively, and to develop new dual purpose maize varieties without sacrificing grain yield.
The researchers screened diverse Asia-adapted CIMMYT maize lines from breeders’ working germplasm for animal feed quality traits. They then used these as a reference set to predict the breeding values of over a thousand doubled haploid lines derived from abiotic stress breeding programs based on genetic information. Based on these breeding values, the scientists further selected 100 of these double haploid lines and validated the performance of stover quality traits through field-based phenotyping.
The results demonstrate the feasibility of incorporating genomic prediction as a tool to improve stover traits, circumventing the need for field or lab-based phenotyping. The findings significantly reduce the need for additional testing resources — a major hindrance in breeding dual-purpose maize varieties.
Interestingly, the researchers found that increased animal feed quality in maize stover had no impact on grain yield, a concern raised by scientists in the past.
“The main purpose of this study and overall purpose of this CIMMYT and ILRI collaboration was to optimize the potential of maize crops for farm families, increase income, improve livelihoods and sustainably manage the crop livestock system, within limited resources,” said P.H. Zaidi, a maize physiologist at CIMMYT and co-author of the study.
“More than 70% of the farmers in the tropics are smallholders so they don’t have a lot of land to grow crops for grain purposes and separate stover for animal feed, so this is a very sustainable model if they grow dual purpose maize.”
By growing maize simultaneously for both human consumption and animal feed, farmers can get the most out of their crops and conserve natural resources like land and water.
A farmer works in a maize field close to the Pusa site of the Borlaug Institute for South Asia (BISA), in the Indian state of Bihar. (Photo: M. DeFreese/CIMMYT)
Fodder for thought
The findings from this study also validate the use of genomic prediction as an important breeding tool to accelerate the development and improvement of dual-purpose maize varieties, according to CIMMYT Maize Breeder and first author of the study, M.T. Vinayan.
With the demand for animal feed increasing around the world, crop scientists and breeders have been exploring more efficient ways to improve animal feed quality in cereals without compromising grain yields for human consumption.
“Not all maize varieties have good stover quality, which is what we realized when we started working on this project. However, we discovered that there are a few which offer just as good quality as sorghum stover — a major source of livestock fodder particularly in countries such as India,” said Zaidi.
The publication of the study is a fitting tribute to the late Michael Blummel, who was a principal scientist and deputy program leader in the feed and forage development program at ILRI and co-author of this study.
“A couple of years back Dr Blummel relocated from the Hyderabad office at ILRI to its headquarters at Addis Ababa, but he used to frequently visit Hyderabad, and without fail met with us on each visit to discuss updates, especially about dual-purpose maize work. He was very passionate about dual-purpose maize research with a strong belief that the additional income from maize stover at no additional cost will significantly improve the income of maize farmers,” Zaidi said. “Michael was following this publication very closely because it was the first of its kind in terms of molecular breeding for dual purpose maize. He would have been very excited to see this published.”
The proportion of children under five years old who are stunted in Zimbabwe is estimated to be 28%. Stunting leads to a higher risk of dying, poorer school performance and lower wages in adult life. Improving the quantity and quality of food for children under two years of age is the best approach we have to prevent stunting. An earlier project (Sanitation, Hygiene, Infant Nutrition Efficacy, SHINE) provided mothers with information on infant and young child feeding (IYCF) and provided a daily supplement (Nutributter) to provide extra calories and vitamins to children. However, many children still did not meet their daily nutrient requirements and over one-quarter remained stunted.
The SHINE data showed that nutrient intake remained insufficient to meet both macro- and micronutrient requirements for most children. The overarching hypothesis of the CHAIN project is that this nutrient gap can be filled by a combined agriculture and infant-feeding intervention.
Objectives:
Deliver an integrated agriculture and infant feeding intervention (“IYCF-plus”) to households in a randomized, community-based trial in rural Zimbabwe
Evaluate the impact of IYCF-plus on nutrient intake and growth in young children at risk of stunting
Evaluate the impact of the IYCF-plus intervention on biological barriers to nutrient uptake and utilization
Identify metabolic signatures of the IYCF-plus intervention in young children
A handful of improved maize seed from the drought-tolerant variety TAN 250, developed and registered for sale in Tanzania through CIMMYT’s Drought Tolerant Maize for Africa (DTMA) project, in partnership with Tanzanian seed company Tanseed International Limited. It is based on material from CIMMYT-Zimbabwe, CIMMYT-Mexico, and Tanzania. (Photo: Anne Wangalachi/CIMMYT)
The CGIAR Research Program on Maize (MAIZE) “uniquely fills a gap at the global and regional level, positioning it to continue catalyzing good science across borders,” according to a new report.
In addition to the exceptional quality of the program’s scientific inputs and the overall quality of its outputs, the reviewers note the program’s capacity to mobilize “stakeholders, resources and knowledge to rapidly deliver valuable solutions for a critical need.” The review authors specifically note MAIZE’s efforts towards halting the spread of maize lethal necrosis (MLN).
While, like all CGIAR Research Programs, MAIZE is due to conclude at the end of 2021, much of the program’s pioneering work will continue under new guises, such as the Accelerating Genetic Gains in Maize and Wheat for Improved Livelihoods (AGG) project.
MAIZE — led by CIMMYT in partnership with the International Institute of Tropical Agriculture (IITA) — spearheads international, multi-stakeholder research for development to improve the livelihoods and food security of poor maize producers and consumers. It simultaneously seeks to strengthen the sustainability of maize-based agri-food systems. The program focuses on maize production in low- to middle-income countries — accounting for approximately two-thirds of global maize production — where the crop is “key to the food security and livelihoods of millions of poor famers,” according to the report.
“MAIZE provides a very robust platform for collaboration with our national partners, including private companies, community seed produces and other stakeholders. Through projects such as Drought Tolerant Maize for Africa (DTMA) and STMA, research has been able to provide innovative solutions to challenges that smallholder farmers face in their daily lives, such as drought, poor soils, and pests and diseases,” says Nteranya Sanginga, IITA’s Director General.
The review concludes that MAIZE “good management and governance practice are a strong foundation for the remainder of [the program’s] running.” The reviewers also recommend that the “excellent,” participatory application of theory of change thinking in the second phase of MAIZE be mainstreamed at the CGIAR system level moving forward. Key recommendations for the program’s final phase include:
Building on MAIZE’s “strong network of partners” by deepening these relationships into “multidirectional partnerships.”
Building on existing cross-cutting work on capacity development, climate change, gender and youth.
Diversifying and expanding MAIZE’s knowledge dissemination efforts to more deeply engage with include multiple and non-scientific audiences.
A new publication in Virus Research shows that these second-generation MLN-resistant hybrids developed by the International Maize and Wheat Improvement Center (CIMMYT) offer better yields and increased resilience against MLN and other stresses.
Scientists are calling for accelerated adoption of new hybrid maize varieties with resistance to maize lethal necrosis (MLN) disease in sub-Saharan Africa. In combination with recommended integrated pest management practices, adopting these new varieties is an important step towards safeguarding smallholder farmers against this devastating viral disease.
A new publication in Virus Research shows that these second-generation MLN-resistant hybrids developed by the International Maize and Wheat Improvement Center (CIMMYT) offer better yields and increased resilience against MLN and other stresses. The report warns that the disease remains a key threat to food security in eastern Africa and that, should containment efforts slacken, it could yet spread to new regions in sub-Saharan Africa.
The publication was co-authored by researchers at the International Maize and Wheat Improvement Center (CIMMYT), Kenya Agricultural and Livestock Research Organization (KALRO), the Alliance for a Green Revolution in Africa (AGRA), the African Agricultural Technology Foundation (AATF) and Aarhus University in Denmark.
CIMMYT technician Janet Kimunye (right) shows visitors a plant with MLN symptoms at the MLN screening facility in Naivasha, Kenya. (Photo: CIMMYT)
Stemming the panic
The first reported outbreak of MLN in Bomet County, Kenya in 2011 threw the maize sector into a panic. The disease caused up to 100% yield loss. Nearly all elite commercial maize varieties on the market at the time were susceptible, whether under natural of artificial conditions. Since 2012, CIMMYT, in partnership with KALRO, national plant protection organizations and commercial seed companies, has led multi-stakeholder, multi-disciplinary efforts to curb MLN’s spread across sub-Saharan Africa. Other partners in this endeavor include the International Institute of Tropical Agriculture (IITA), non-government organizations such as AGRA and AATF, and advanced research institutions in the United States and Europe.
In 2013 CIMMYT established an MLN screening facility in Naivasha. Researchers developed an MLN-severity scale, ranging from 1 to 9, to compare varieties’ resistance or susceptibility to the disease. A score of 1 represents a highly resistant variety with no visible symptoms of the disease, while a score of 9 signifies extreme susceptibility. Trials at this facility demonstrated that some of CIMMYT’s pre-commercial hybrids exhibited moderate MLN-tolerance, with a score of 5 on the MLN-severity scale. CIMMYT then provided seed and detailed information to partners for evaluation under accelerated National Performance Trials (NPTs) for varietal release and commercialization in Kenya, Tanzania and Uganda.
Between 2013 and 2014, four CIMMYT-derived MLN-tolerant hybrid varieties were released by public and private sector partners in East Africa. With an average MLN severity score of 5-6, these varieties outperformed commercial MLN-sensitive hybrids, which averaged MLN severity scores above 7. Later, CIMMYT breeders developed second-generation MLN-resistant hybrids with MLN severity scores of 3–4. These second-generation hybrids were evaluated under national performance trials. This led to the release of several hybrids, especially in Kenya, over the course of a five-year period starting in 2013. They were earmarked for commercialization in East Africa beginning in 2020.
Maize Lethal Necrosis (MLN) sensitive and resistant hybrid demo plots in Naivasha’s quarantine & screening facility (Photo: KIPENZ/CIMMYT)
Widespread adoption critical
The last known outbreak of MLN was reported in 2014 in Ethiopia, marking an important break in the virus’s spread across the continent. Up to that point, the virus had affected the Democratic Republic of the Congo, Kenya, Rwanda, Tanzania and Uganda. However, much remains to be done to minimize the possibility of future outbreaks.
“Due to its complex and multi-faceted nature, effectively combating the incidence, spread and adverse effects of MLN in Africa requires vigorous and well-coordinated efforts by multiple institutions,” said B.M. Prasanna, primary author of the report and director of the Global Maize Program at CIMMYT and of the CGIAR Research Program on Maize (MAIZE). Prasanna also warns that most commercial maize varieties being cultivated in eastern Africa are still MLN-susceptible. They also serve as “reservoirs” for MLN-causing viruses, especially the maize chlorotic mottle virus (MCMV), which combines with other viruses from the Potyviridae family to cause MLN.
“This is why it is very important to adopt an integrated disease management approach, which encompasses extensive adoption of improved MLN-resistant maize varieties, especially second-generation, not just in MLN-prevalent countries but also in the non-endemic ones in sub-Saharan Africa,” Prasanna noted.
The report outlines other important prevention and control measures including: the production and exchange of “clean” commercial maize seed with no contamination by MLN-causing viruses; avoiding maize monocultures and continuous maize cropping; practicing maize crop rotation with compatible crops, especially legumes, which do not serve as hosts for MCMV; and continued MLN disease monitoring and surveillance.
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)
Noteworthy wins
In addition to the development of MLN-resistant varieties, the fight against MLN has delivered important wins for both farmers and their families and for seed companies. In the early years of the outbreak, most local and regional seed companies did not understand the disease well enough to produce MLN-pathogen free seed. Since then, CIMMYT and its partners developed standard operating procedures and checklists for MLN pathogen-free seed production along the seed value chain. Today over 30 seed companies in Ethiopia, Kenya, Uganda, Rwanda and Tanzania are implementing these protocols on a voluntary basis.
“MLN represents a good example where a successful, large-scale surveillance system for an emerging transboundary disease has been developed as part of a rapid response mechanism led by a CGIAR center,” Prasanna said.
Yet, he noted, significant effort and resources are still required to keep the maize fields of endemic countries free of MLN-causing viruses. Sustaining these efforts is critical to the “food security, income and livelihoods of resource-poor smallholder farmers.
To keep up with the disease’s changing dynamics, CIMMYT and its partners are moving ahead with novel techniques to achieve MLN resistance more quickly and cheaply. Some of these innovative techniques include genomic selection, molecular markers, marker-assisted backcrossing, and gene editing. These techniques will be instrumental in developing elite hybrids equipped not only to resist MLN but also to tolerate rapidly changing climatic conditions.
Cover photo: Researchers and visitors listen to explanations during a tour of infected maize fields at the MLN screening facility in Naivasha, Kenya. (Photo: CIMMYT)
The International Maize and Wheat Improvement Centre (CIMMYT) has developed new maize hybrid varieties showing promising resistance to the destructive fall armyworm pest, which has been causing huge crop losses ever since the pest was first reported in Africa in 2016.
Global thought leader, philanthropist and one of the International Maize and Wheat Improvement Center (CIMMYT) and CGIAR’s most vocal and generous supporters, Bill Gates, wrote a book about climate change and is now taking it around the world on a virtual book tour to share a message of urgency and hope.
The International Maize and Wheat Improvement Center (CIMMYT) is offering a new set of elite, improved maize hybrids to partners in eastern Africa and similar agro-ecological zones. National agricultural research systems (NARS) and seed companies are invited to apply for licenses to pursue national release of, and subsequently commercialize, these new hybrids, in order to bring the benefits of the improved seed to farming communities.
