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Adult plant resistance (APR): the strategy to beat persistent pathogens

Scientists examine Ug99 stem rust symptoms on wheat. (Photo: Petr Kosina/CIMMYT)

The three rust diseases, yellow (stripe) rust, black (stem) rust, and brown (left) rust occur in most wheat production environments, causing substantial yield losses and under serious epidemics, can threaten the global wheat supply.

CIMMYT is one of the largest providers of elite germplasm to national partners in over 80 countries. CIMMYT nurseries, known for research in developing adaptive, high-yielding and high-quality germplasm, also carry resistance to several biotic and abiotic stresses, such as rust disease.

Through years of research and experience, CIMMYT has found that durable control of wheat rusts can be achieved by developing and deploying wheat varieties with complex adult-plant resistance (APR). A combination of both conventional and modern technologies in APR will enable breeders to address the problem of rusts and other diseases and continue progress in delivering higher genetic gains, a key goal of the Accelerating Genetic Gains in Maize and Wheat (AGG) project.

Learn more about CIMMYT’s APR strategy: CIMMYT Strategy for Adult Plant Resistance (APR)

For more information on CIMMYT’s APR strategy, contact CIMMYT’s Head of Wheat Rust Pathology and Molecular Genetics, Sridhar Bhavani.

A view from above

Scientists at the International Maize and Wheat Improvement Center (CIMMYT) have been harnessing the power of drones and other remote sensing tools to accelerate crop improvement, monitor harmful crop pests and diseases, and automate the detection of land boundaries for farmers.

A crucial step in crop improvement is phenotyping, which traditionally involves breeders walking through plots and visually assessing each plant for desired traits. However, ground-based measurements can be time-consuming and labor-intensive.

This is where remote sensing comes in. By analyzing imagery taken using tools like drones, scientists can quickly and accurately assess small crop plots from large trials, making crop improvement more scalable and cost-effective. These plant traits assessed at plot trials can also be scaled out to farmers’ fields using satellite imagery data and integrated into decision support systems for scientists, farmers and decision-makers.

Here are some of the latest developments from our team of remote sensing experts.

An aerial view of the Global Wheat Program experimental station in Ciudad Obregón, Sonora, Mexico (Photo: Francisco Pinto/CIMMYT)

Measuring plant height with high-powered drones

A recent study, published in Frontiers in Plant Science validated the use of drones to estimate the plant height of wheat crops at different growth stages.

The research team, which included scientists from CIMMYT, the Federal University of Viçosa and KWS Momont Recherche, measured and compared wheat crops at four growth stages using ground-based measurements and drone-based estimates.

The team found that plant height estimates from drones were similar in accuracy to measurements made from the ground. They also found that by using drones with real-time kinematic (RTK) systems onboard, users could eliminate the need for ground control points, increasing the drones’ mapping capability.

Recent work on maize has shown that drone-based plant height assessment is also accurate enough to be used in maize improvement and results are expected to be published next year.

A map shows drone-based plant height estimates from a maize line trial in Muzarabani, Zimbabwe. (Graphic: CIMMYT)

Advancing assessment of pests and diseases

CIMMYT scientists and their research partners have advanced the assessment of Tar Spot Complex — a major maize disease found in Central and South America — and Maize Streak Virus (MSV) disease, found in sub-Saharan Africa, using drone-based imaging approach. By analyzing drone imagery, scientists can make more objective disease severity assessments and accelerate the development of improved, disease-resistant maize varieties. Digital imaging has also shown great potential for evaluating damage to maize cobs by fall armyworm.

Scientists have had similar success with other common foliar wheat diseases, Septoria and Spot Blotch with remote sensing experiments undertaken at experimental stations across Mexico. The results of these experiments will be published later this year. Meanwhile, in collaboration with the Federal University of Technology, based in Parana, Brazil, CIMMYT scientists have been testing deep learning algorithms — computer algorithms that adjust to, or “learn” from new data and perform better over time — to automate the assessment of leaf disease severity. While still in the experimental stages, the technology is showing promising results so far.

CIMMYT researcher Gerald Blasch and EIAR research partners Tamrat Negash, Girma Mamo and Tadesse Anberbir (right to left) conduct field work in Ethiopia. (Photo: Tadesse Anberbir)

Improving forecasts for crop disease early warning systems

CIMMYT scientists, in collaboration with Université catholique de Louvain (UCLouvain), Cambridge University and the Ethiopian Institute of Agricultural Research (EIAR), are currently exploring remote sensing solutions to improve forecast models used in early warning systems for wheat rusts. Wheat rusts are fungal diseases that can destroy healthy wheat plants in just a few weeks, causing devastating losses to farmers.

Early detection is crucial to combatting disease epidemics and CIMMYT researchers and partners have been working to develop a world-leading wheat rust forecasting service for a national early warning system in Ethiopia. The forecasting service predicts the potential occurrence of the airborne disease and the environmental suitability for the disease, however the susceptibility of the host plant to the disease is currently not provided.

CIMMYT remote sensing experts are now testing the use of drones and high-resolution satellite imagery to detect wheat rusts and monitor the progression of the disease in both controlled field trial experiments and in farmers’ fields. The researchers have collaborated with the expert remote sensing lab at UCLouvain, Belgium, to explore the capability of using European Space Agency satellite data for mapping crop type distributions in Ethiopia. The results will be also published later this year.

CIMMYT and EIAR scientists collect field data in Asella, Ethiopia, using an unmanned aerial vehicle (UAV) data acquisition. (Photo: Matt Heaton)

Delivering expert irrigation and sowing advice to farmers phones

Through an initiative funded by the UK Space Agency, CIMMYT scientists and partners have integrated crop models with satellite and in-situ field data to deliver valuable irrigation scheduling information and optimum sowing dates direct to farmers in northern Mexico through a smartphone app called COMPASS — already available to iOS and Android systems. The app also allows farmers to record their own crop management activities and check their fields with weekly NDVI images.

The project has now ended, with the team delivering a webinar to farmers last October to demonstrate the app and its features. Another webinar is planned for October 2021, aiming to engage wheat and maize farmers based in the Yaqui Valley in Mexico.

CIMMYT researcher Francelino Rodrigues collects field data in Malawi using a UAV. (Photo: Francelino Rodrigues/CIMMYT)

Detecting field boundaries using high-resolution satellite imagery

In Bangladesh, CIMMYT scientists have collaborated with the University of Buffalo, USA, to explore how high-resolution satellite imagery can be used to automatically create field boundaries.

Many low and middle-income countries around the world don’t have an official land administration or cadastre system. This makes it difficult for farmers to obtain affordable credit to buy farm supplies because they have no land titles to use as collateral. Another issue is that without knowing the exact size of their fields, farmers may not be applying to the right amount of fertilizer to their land.

Using state of the art machine learning algorithms, researchers from CIMMYT and the University of Buffalo were able to detect the boundaries of agricultural fields based on high-resolution satellite images. The study, published last year, was conducted in the delta region of Bangladesh where the average field size is only about 0.1 hectare.

A CIMMYT scientist conducts an aerial phenotyping exercise in the Global Wheat Program experimental station in Ciudad Obregón, Sonora, Mexico. (Photo: Francisco Pinto/CIMMYT)

Developing climate-resilient wheat

CIMMYT’s wheat physiology team has been evaluating, validating and implementing remote sensing platforms for high-throughput phenotyping of physiological traits ranging from canopy temperature to chlorophyll content (a plant’s greenness) for over a decade. Put simply, high-throughput phenotyping involves phenotyping a large number of genotypes or plots quickly and accurately.

Recently, the team has engaged in the Heat and Drought Wheat Improvement Consortium (HeDWIC) to implement new high-throughput phenotyping approaches that can assist in the identification and evaluation of new adaptive traits in wheat for heat and drought.

The team has also been collaborating with the Accelerating Genetic Gains in Maize and Wheat (AGG) project, providing remote sensing data to improve genomic selection models.

Cover photo: An unmanned aerial vehicle (UAV drone) in flight over CIMMYT’s experimental research station in Ciudad Obregon, Mexico. (Photo: Alfredo Saenz/CIMMYT)

A challenge solved

Wheat stalks grow in a in India. (Photo: Saad Akhtar)
Wheat stalks grow in a field in India. (Photo: Saad Akhtar)

For scientists, determining how best to increase wheat yields to meet food demand is a persistent challenge, particularly as the trend toward sustainably intensifying production on agricultural lands grows.

The United Nations projects that the current global population of 7.6 billion will increase to more than 9.8 billion by 2050, making higher grain yield potential vital, particularly as climate instability increases due to global warming. International efforts are also focused on meeting the Zero Hunger target detailed in the UN Sustainable Development Goals before they expire in 2030.

Now, a new landmark research survey on the grain yield potential and climate-resilience of bread wheat (Triticum aestivum L.) has brought scientists a few strides closer to meeting their ambitions.

Grain yield has traditionally been an elusive trait in genomic wheat breeding because of its quantitative genetic control, which means that it is controlled by many genomic regions with small effects.

Challenges also include a lack of good understanding about the genetic basis of grain yield, inconsistent grain yield quantitative trait loci identified in different environments, low heritability of grain yield across environments and environment interactions of grain yield.

To dissect the genetic architecture of wheat grain yield for the purposes of the research, which appeared in Scientific Reports, researchers implemented a large-scale genome-wide association study based on 100 datasets and 105,000 grain yield observations from 55,568 wheat breeding lines developed by the International Maize and Wheat Improvement Center (CIMMYT).

They evaluated the lines between 2003 and 2019 in different sites, years, planting systems, irrigation systems and abiotic stresses at CIMMYT’s primary yield testing site, the Norman E. Borlaug Experimental Research Station, Ciudad Obregon, Mexico, and in an additional eight countries — including Afghanistan, India and Myanmar — through partnerships with national programs.

The researchers also generated the grain-yield associated marker profiles and analyzed the grain-yield favorable allele frequencies for a large panel of 73,142 wheat lines, resulting in 44.5 million data points. The marker profiles indicated that the CIMMYT global wheat germplasm is rich in grain yield favorable alleles and is a trove for breeders to choose parents and design strategic crosses based on complementary grain yield alleles at desired loci.

“By dissecting the genetic basis of the elusive grain-yield trait, the resources presented in our study provide great opportunities to accelerate genomic breeding for high-yielding and climate-resilient wheat varieties, which is a major objective of the Accelerating Genetic Gain in Maize and Wheat project,” said CIMMYT wheat breeder Philomin Juliana.

“This study is unique and the largest-of-its-kind focusing on elucidating the genetic architecture of wheat grain yield,” she explained, “a highly complex and economically important trait that will have great implications on future diagnostic marker development, gene discovery, marker-assisted selection and genomic-breeding in wheat.”

Currently, crop breeding methods and agronomic management put annual productivity increases at 1.2% a year, but to ensure food security for future generations, productivity should be at 2.4% a year.

So, the extensive datasets and results presented in this study are expected to provide a framework for breeders to design effective strategies for mitigating the effects of climate change, while ensuring food-sustainability and security.

Buying into new seed

Mary Nzau enters a mock agrodealer shop set up on a field on the outskirts of Tala town in Machakos County, Kenya. On display are nine 2kg bags of hybrid maize seed. She picks one. By the look of it, her mind is made up. After a quick scan of the shelf, she has in her hand the variety that she has been purchasing for years.

Regina Mbaika Mutua is less lucky. The variety she always buys is not on display in the mock shop. As part of the experiment, the research team has removed from the shelf the variety she indicated she usually buys. The team’s goal is to observe what factors influence her seed purchase decision in the absence of the variety she was expecting to purchase.

“Although I did not find the variety I was looking for, I picked an alternative as I have seen it perform well on a neighboring farm,” Mutua says, adding that she will plant it this season alongside recycled (farm-saved) seed on her one-acre farm.

Michael Mutua passes up the popular variety he has been planting for the previous two years. He picks one that has been advertised extensively on local radio. “I have heard about it severally on radio. I would like to experiment with this new seed and see how it performs on my farm. Should I like the results, I will give it a chance in ensuing seasons,” he says.

Pieter Rutsaert explains the study setup at a mock agrodealer shop. (Photo: Joshua Masinde/CIMMYT)
Pieter Rutsaert explains the study setup at a mock agrodealer shop. (Photo: Joshua Masinde/CIMMYT)

The big adoption conundrum

The goal of the out-of-stock study is to improve an understanding of how farmers make their maize seed choices, says Pieter Rutsaert, Markets and Value Chain Specialist at the International Maize and Wheat Improvement Center (CIMMYT).

“We do this by inviting farmers to a mock agrodealer store that we set up in their villages and give them a small budget to purchase a bag of seed. However, not all farmers walk into the same store: some will find their preferred variety, others won’t. Some will have access to additional trait information or see some varieties with price promotions while others don’t.”

Rutsaert acknowledges that breeding programs and their partner seed companies have done a great job at giving farmers access to maize hybrids with priority traits such as drought tolerance and high yield. CIMMYT then works closely with local seed companies to get varieties into the hands of farmers. “We want to extend that support by providing insights to companies and public breeding programs on how to get new varieties more quickly into the hands of farmers,” he says.

Pauline Muindi (left), gender research associate with CIMMYT, acts as a mock agrodealer clerk and attends a farmer. (Photo: CIMMYT)
Pauline Muindi (left), gender research associate with CIMMYT, acts as a mock agrodealer clerk and attends a farmer. (Photo: CIMMYT)

The hybrid maize seed sector in Kenya is highly competitive. Amid intensifying competition, new varieties face a daunting task breaking into the market, independent of their quality. While farmers now have more options to pick from, a major challenge has been how to get them to adopt new varieties.

“Moving farmers from something they know to something they don’t is not easy. They tend to stick with what they know and have been growing for years,” Rutsaert says.

Pauline Muindi, gender research associate with CIMMYT, acted as the stand-in clerk at the mock store. She noticed that farmers tend to spend very little time in the shop when their preferred variety is available. However, this all changes in the out-of-stock situation, pushing farmers to step out of their comfort zone and explore new options.

The first step to overcoming this challenge is to entice maize farmers to try a new seed variety, even just once, Rutsaert observes. If it is a good variety, farmers will see that and then the market will work in its favor: farmers will come back to that variety in subsequent years and tell others about it.

“The good news is that many of the varieties we are currently seeing on the market have performed well — that’s why they’re popular. But there are newer varieties that are even better, especially in terms of attributes like drought tolerance. We would like to understand how farmers can be convinced to try out these newer varieties. Is it about the need for more awareness on varietal traits? Can we use price promotions? Or are there other factors?” he says.

A researcher interviews Mary Nzau (right), a farmer from Tala town in Machakos County, after her mock purchase. (Photo: Joshua Masinde/CIMMYT)
A researcher interviews Mary Nzau (right), a farmer from Tala town in Machakos County, after her mock purchase. (Photo: Joshua Masinde/CIMMYT)

Does seed price matter?

“With today’s climate uncertainty, it is better to stick to a variety that is adapted to such climate rather than banking on a variety one is oblivious of. The risk is not worth it,” Nzau says. She adds that she would rather buy a higher-priced seed packet she knows and trusts than a lower-priced one that she has not used in the past. Radio promotions of new or other varieties have limited sway over her decision to make the switch.

Faith Voni, another farmer, agrees. “It is better to purchase a higher-priced variety whose quality I can vouch for than risk purchasing a lower-priced one that I know little about. I do not wish to take such a risk.” Voni says she would also be more inclined to experiment with another variety that she had seen perform well on a neighbor’s farm.

Michael Mutua holds a different view. “If there is an option of an equally good but new variety that is lower-priced than the variety I prefer, my wallet decides,” he says.

Vivian Hoffmann, an economist at the International Food Policy Research Institute (IFPRI) and collaborator on the study, says price can be key for convincing consumers to try a new product. “Our previous research on maize flour choice found that a provisional 10 percent discount boosted sales tremendously,” Hoffmann says. “Of course, that only gets your foot in the door; after that, a new variety will need to win farmers over based on its merits.”

Hoffmann is interested in the extent to which drawing farmers’ attention to key varietal attributes influences their seed choice. “This information is generally already available on seed packets, but we live in a world of information overload. Promoting certain attributes through in-store signage is an approach that is widely used to help consumers make more healthier food choices. Doing the same for new seed varieties makes a lot of sense.”

Michael Mutua (left) responds to preliminary questions from one of the research team members before proceeding to make his seed selection at the mock agrodealer shop. (Photo: Joshua Masinde/CIMMYT)
Michael Mutua (left) responds to preliminary questions from one of the research team members before proceeding to make his seed selection at the mock agrodealer shop. (Photo: Joshua Masinde/CIMMYT)

The value of drought tolerance

Situated on Kenya’s eastern region, Machakos is characterized by persistent water stress. Climate change induced erratic rainfall has pushed traits that can tolerate the unfavorable weather conditions in the favorite’s corner. While other traits such as high yield and disease resistance are equally important, the seed, when planted, must first withstand the effects of droughts or water stress in some seasons and germinate. This is the most crucial step in the long journey to either a decent, bare minimum or no yield. A lot of farmers still plant recycled seed alongside hybrid varieties. But these are no match to water stress conditions, which decimate fields planted with farmer-saved seed.

“If a variety is not climate resilient, I will likely not harvest anything at all,” says Nzau. She has planted a drought-tolerant variety for ten years now. Prior to that, she had planted about three other varieties as well as recycled seed. “The only advantage with recycled seed is that given the right amount of rainfall, they mature fast — typically within two months. This provides my family with an opportunity to eat boiled or roast maize,” she notes.

However, varieties need to do more than just survive harsh weather conditions. Breeders face a daunting task of incorporating as many traits as possible to cater to the overarching and the specific interests of multiple farmers. As Murenga Mwimali, a maize breeder at the Kenya Agricultural and Livestock Research Organization (KALRO) and collaborator in this research says, innovations in breeding technologies are making breeding more efficient.

“It is better to have a diversity of product profiles as different market niches are captured within a particular agroecological zones. This is such that farmers may not just benefit from the minimum traits like drought tolerance, but also more specific traits they are looking for,” Mwimali says.

Smallholder farmers continue to play a central role in the seed development process. Capturing what happens at the point of purchase, for instance, at the agrodealer, and understanding how they purchase seed offers valuable insights on the traits that are deemed essential in the breeding process. This work contributes to CIMMYT’s focus on fast-tracking varietal turnover by turning the levers towards a demand-driven seed system.

Cover photo: Pauline Muindi, gender research associate with CIMMYT, at the mock agrodealer shop where she acted as a clerk. (Photo: CIMMYT)

Fighting the stress

East African Seed Company has a rich history of nearly 50 years, serving farmers with improved climate-resilient seed varieties. Established in 1972, the company produces and sells improved seed, through a wide distribution network in at least 15 countries in sub-Saharan Africa. It also markets agrochemicals and other farm inputs, and has ambitions of expanding to the rest of Africa, trading as Agriscope Africa Limited.

Smallholder farmers in sub-Saharan Africa continue to face multiple biotic and abiotic stresses as they try to improve their farms’ productivity and their livelihoods. Maize seed that guarantees high yield is a key trait, coupled with other key attributes such as drought tolerance, disease and pest resistance, early seedling vigor as well as suitability for food and animal feed.

With the varieties serving both small- and large-scale commercial farmers, challenges such as the fall armyworm, diminishing soil fertility and erratic rains have persisted in recent years and remain as key farming obstacles. “Such challenges diminish crop production and the grain quality thereby, lessening farmers’ profitability,” says Rogers Mugambi, Chief Operating Officer of East African Seed Company.

Scientists at the International Maize and Wheat Improvement Center (CIMMYT), in collaboration with partners in the national agriculture research systems and the commercial seed sector, continue to develop seed varieties that can guarantee decent yield even in times of climatic, disease and pest stress.

General view of the East African Seed warehouse. (Photo: Jerome Bossuet/CIMMYT)
General view of the East African Seed warehouse. (Photo: Jerome Bossuet/CIMMYT)

Top-notch research trickles down to farmers

Over the years, East African Seed has inked partnerships with CIMMYT, national research institutes and other agencies in the countries where it operates. Such partnerships have been the driving force to its success and the impacts within the farming communities in sub-Saharan Africa.

“Our collaboration with CIMMYT began in 2008 with germplasm acquisition. The cooperation has expanded to include testing networks for new hybrids, early-generation seed production and marketing. The overall beneficiary is the smallholder farmer who can access quality seeds and produce more with climate-smart products,” Mugambi says.

Apart from the multi-stress-tolerant varieties developed and released over time by the national agricultural research programs, CIMMYT recently announced a breakthrough: fall armyworm-tolerant elite maize hybrids for eastern and southern Africa. This success followed three years of rigorous research and experiments conducted in Kenya and signified a key milestone in the fight against fall armyworm.

As part of the partnership in the Drought Tolerant Maize for Africa (DTMA) and Stress Tolerant Maize for Africa (STMA) projects, East African Seed Company (Agriscope Africa Limited) established demonstration farms and conducted field days in Kenya, reaching thousands of farmers as a result. It was also able to produce early generation seed, which supported production of 2,000 metric tons of certified seed. This partnership now continues in the Accelerating Genetic Gains in Maize and Wheat (AGG) project.

The company has contracted large- and small-scale growers across the country to meet its seed production targets.

“Most of our small-scale growers are clustered in groups of up to 30 farmers with less than five acres of farmland. The large growers have advanced irrigation facilities such as the pivot system and seed processing plants. The seed from the fields is pre-cleaned and dried in the out-grower facilities before delivery to our factory for further cleaning and processing,” Mugambi explains.

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. (Photo: Anne Wangalachi/CIMMYT)
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. (Photo: Anne Wangalachi/CIMMYT)

Out with the drought

Currently, of the 1,300 metric tons of drought-tolerant hybrid seeds it produces yearly, 500 metric tons constitute those derived from the partnership in the STMA project. Two notable hybrids,  HODARI (MH501) and TOSHEKA (MH401), were derived during the DTMA and STMA projects. Released in 2014 and accepted for regional certification through the Common Market for Eastern and Southern Africa (COMESA)’s regional catalogue, the MH501 is a mid-altitude adapted and medium maturing three-way cross hybrid. The yield advantage of 15% over the local commercial checks triggered widespread adoption by the farmers, according to Mugambi. In Kenya, it was used as a commercial check during national performance trials, from 2017 to 2019.

The MH401, an early maturing hybrid with moderate drought tolerance, has been adopted in lowland and mid-altitude dry ecologies of Kenya and Tanzania. It has a 20% yield advantage over the local commercial checks.

As part of its varietal replacement, East African Seed Company looks to steadily retire older varieties such as KH600-15A and WE1101 and promote new ones including TAJIRI (EASH1220), TAJI (MH502) and FARAJA (MH503).

To promote new varieties and successfully reach smallholders, the company conducts field days, farm-level varietal demonstrations, road shows and radio programs. It also disseminates information on the benefits of new varieties while also dispensing promotional materials such as branded t-shirts and caps.

“Additionally, we organize annual field days at our research farm in Thika, where key and influential farmers and other stakeholders are invited from across Kenya and neighboring countries to learn about our new agricultural technologies,” Mugambi says.

Researchers identify optimal strategy to maximize genomic estimated breeding values

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)
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.”

Read the study:
Maximizing efficiency of genomic selection in CIMMYT’s tropical maize breeding program

Drought-tolerant maize project pioneers a winning strategy for a world facing climate change

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)
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.”

First complete cytological characterization of the 2NvS translocation

Wheat infected with the blast fungus in Meherpur, Bangladesh, in 2019. (Photo: PLOS Biology)
Wheat infected with the blast fungus in Meherpur, Bangladesh, in 2019. (Photo: PLOS Biology)

As scientists study and learn more about the complicated genetic makeup of the wheat genome, one chromosomal segment has stood out, particularly in efforts to breed high-yielding wheat varieties resistant to devastating and quickly spreading wheat diseases.

Known as the 2NvS translocation, this segment on the wheat genome has been associated with grain yield, tolerance to wheat stems bending over or lodging, and multiple-disease resistance.

Now, thanks to a new multi-institution study led by wheat scientist Liangliang Gao of Kansas State University, we have a clearer picture of the yield advantage and disease resistance conferred by this chromosomal segment for wheat farmers — and more opportunities to capitalize on these benefits for future breeding efforts.

The Aegilops ventricosa 2NvS segment in bread wheat: cytology, genomics and breeding, published in Theoretical and Applied Genetics, summarizes the collaborative effort by scientists from several scientific institutions — including International Maize and Wheat Improvement Center (CIMMYT) head of global wheat improvement Ravi Singh and wheat scientist Philomin Juliana —  to conduct the first complete cytological characterization of the 2NvS translocation.

A rich background

The 2NvS translocation segment has been very valuable in disease-resistance wheat breeding since the early 1990s. Originally introduced into wheat cultivar VPM1 by the French cytogeneticist Gerard Doussinault in 1983 by crossing with a wild wheat relative called Aegilops ventricosa, the segment has been conferring resistance to diseases like eye spot (Pch1 gene), leaf rust (Lr37 gene), stem rust (Sr38 gene), stripe rust (Yr17 gene), cereal cyst (Cre5 gene), root knot (Rkn3 gene) and wheat blast.

The high-yielding blast-resistant CIMMYT-derived varieties BARI Gom 33 and WMRI#3 (equivalent to Borlaug100),released in Bangladesh to combat a devastating outbreak of wheat blast in the region, carry the 2NvS translocation segment for blast resistance.

Earlier research by Juliana and others found that the proportion of lines with the 2NvS translocation had increased by 113.8% over seven years in CIMMYT’s international bread wheat screening nurseries: from 44% in 2012 to 94.1% in 2019. It had also increased by 524.3% in the semi-arid wheat screening nurseries: from 15% in 2012 to 93.7% in 2019. This study validates these findings, further demonstrating an increasing frequency of the 2NvS translocation in spring and winter wheat breeding programs over the past two decades.

New discoveries

The authors of this study completed a novel assembly and functional annotation of the genes in the 2NvS translocation using the winter bread wheat cultivar Jagger. They validated it using the spring wheat cultivar CDC Stanley and estimated the actual size of the segment to be approximately 33 mega base pairs.

Their findings substantiate that the 2NvS region is rich in disease resistance genes, with more than 10% of the 535 high-confidence genes annotated in this region belonging to the nucleotide-binding leucine-rich repeat (NLR) gene families known to be associated with disease resistance.  This was a higher number of NLRs compared to the wheat segment of the Chinese Spring reference genome that was replaced by this segment, adding further evidence to its multiple-disease resistant nature.

In addition to being an invaluable region for disease resistance, the study makes a strong case that the 2NvS region also confers a yield advantage.  The authors performed yield association analyses using yield data on lines from the Kansas State University wheat breeding program, the USDA Regional Performance Nursery —comprising lines from central US winter wheat breeding programs — and the CIMMYT spring bread wheat breeding program, and found a strong association between the presence of the segment and higher yield.

Global benefits

The yield and disease resistance associations of the 2NvS genetic segment have been helping farmers for years, as seen in the high proportion of the segment present in the improved wheat germplasm distributed globally through CIMMYT’s nurseries.

“The high frequency of the valuable 2NvS translocation in CIMMYT’s internationally distributed germplasm demonstrates well how CIMMYT has served as a key disseminator of lines with this translocation globally that would have likely contributed to a large impact on global wheat production,” said study co-author Juliana.

Through CIMMYT’s distribution efforts, it is likely that national breeding programs have also effectively used this translocation, in addition to releasing many 2NvS-carrying varieties selected directly from CIMMYT distributed nurseries.

With this study, we now know more about why the segment is so ubiquitous and have more tools at our disposal to use it more deliberately to raise yield and combat disease for wheat farmers into the future.

The global network safeguarding the world’s wheat

The new interactive map allows visitors to visually explore the milestones that allowed a global network of researchers to fight threats to wheat production.
The new interactive map allows visitors to visually explore the milestones that allowed a global network of researchers to fight threats to wheat production.

In 2005, preeminent wheat breeder and Nobel Laureate Norman E. Borlaug sounded the alarm to bring the world’s attention to the outbreak of a new variant of stem rust, Ug99, that threatened to wipe out 80% of the world’s wheat.

The result was the Borlaug Global Rust Initiative (BGRI), a global community that pioneered innovative ways for scientists and smallholder farmers around the globe to collaborate on meeting challenges brought about by wheat disease and climate change.

As a founding member of BGRI, the International Maize and Wheat Improvement Center (CIMMYT) and, later, the CGIAR Research Program on Wheat, played a crucial role in the core work of the initiative. They led breeding and large-scale international testing to develop disease resistant wheat varieties, coordinated closely with longstanding national partners to facilitate the release and spread of the varieties to farmers, and contributed to critical disease monitoring and tracking initiatives.

The BGRI has documented these efforts and related resources in a newly released interactive story map: Inside the global network safeguarding the world’s wheat from disease and climate change. The map highlights the BGRI’s efforts from 2005 to 2020 to introduce climate-resilient, disease-resistant wheat to resource-constrained wheat growers around the world, especially in sub-Saharan Africa and South Asia.

When a disease threatens to destroy the world’s most important food crop, who do you call?

The map highlights work undertaken by scientists on the front lines of the Durable Rust Resistance in Wheat (DRRW) and Delivering Genetic Gain in Wheat (DGGW) projects from 2005 to 2020. These achievements formed the foundation for the work that continues today under the auspices of the CIMMYT-led  Accelerating Genetic Gains In Maize and Wheat for Improved Livelihoods (AGG) project.

BGRI scientists from more than 22 national and international agricultural research centers infused resilience into wheat and largely staved off large-scale rust epidemics, working with farmers in East Africa, South Asia and other important bread baskets of the world. The BGRI community improved breeding pipelines, created the world’s most sophisticated pathogen surveillance network, increased capacity in germplasm testing nurseries while conserving and sharing genetic resources, and training new generations of young scientists.

Through videos, photos, interviews, journal articles, blogs, news stories and other resources, the map allows visitors to explore the multifaceted work from hunger fighters in Australia, Canada, China, Ethiopia, India, Kenya, Mexico, Nepal, Russia, the United Kingdom, the United States and other countries.

Written and produced by BGRI cinematographer Chris Knight and associate director for communications Linda McCandless, the map is linked to multimedia and resources from contributors around the world.

Browse the interactive story map:
Inside the Global Network Safeguarding the World’s Wheat from Disease and Climate Change

The DRRW and DGGW projects received funding from the Bill & Melinda Gates Foundation, the UK Foreign, Commonwealth and Development Office, national research institutes, and Cornell University.

Accelerating Genetic Gains in Maize and Wheat for Improved Livelihoods (AGG) brings together partners in the global science community and in national agricultural research and extension systems to accelerate the development of higher-yielding varieties of maize and wheat — two of the world’s most important staple crops. Funded by the Bill & Melinda Gates Foundation, the UK Foreign, Commonwealth & Development Office (FCDO), the U.S. Agency for International Development (USAID) and the Foundation for Food and Agriculture Research (FFAR), AGG fuses innovative methods that improve breeding efficiency and precision to produce and deliver high-yielding varieties that are climate-resilient, pest- and disease-resistant, highly nutritious, and targeted to farmers’ specific needs. 

Research reported in this story was supported by the Foundation for Food and Agriculture Research under award number Grant ID COTF0000000001. The content of this publication is solely the responsibility of the authors and does not necessarily represent the official views of the Foundation for Food and Agriculture Research.

 

Q&A: A decade of improved and climate-smart maize through collaborative research and innovation

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)
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)
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)

Breeders take quantum leap

A CIMMYT technician cuts a leaf sample for DNA extraction. (Photo: CIMMYT)
A CIMMYT technician cuts a leaf sample for DNA extraction. (Photo: CIMMYT)

Wheat breeders from across the globe took a big step towards modernizing their molecular breeding skills at a recent workshop sponsored by the Wheat Initiative, with the CGIAR Excellence in Breeding Platform (EiB) and the International Maize and Wheat Improvement Center (CIMMYT).

The workshop focused on three open-source tools used in molecular breeding: GOBii-GDM for genomic data management, Flapjack for data visualization and breeding analysis, and Galaxy for Genomic Selection. These tools help breeders make selections more quickly and precisely, and ultimately lead to more cost effective and efficient improvement of varieties.

The Wheat Initiative — a global scientific collaboration whose goals are to create improved wheat varieties and disseminate better agronomic practices worldwide — and its Breeding Methods and Strategies expert working group had planned to host these trainings during the 2020 Borlaug Global Rust Initiative Technical Workshop in the United Kingdom. After it became obvious that in-person trainings were not possible, the course organizers — including CIMMYT molecular wheat breeder Susanne Dreisigacker and EiB Adoption Lead and former GOBii project director Elizabeth Jones — decided to come together to host online workshops.

Many of the tools will be incorporated into EiB’s Enterprise Breeding System (EBS), a new integrated data management system being developed for CGIAR breeders. Jones plans to also design training modules for these molecular breeding tools that will be accessible to anyone through the EiB Toolbox.

In the meantime, the tools used in the workshop are all freely available: DArTView, Flapjack (training videos), GOBii-GDM (request access through the web form or by email), and Galaxy Genomic Selection.

The first session of the workshop “Transforming Wheat Breeding Through Integrated Data Management with GOBii and Analysis in Flapjack” benefited breeders from Australia, Canada, Ethiopia, France, India, Ireland, Italy, Morocco, Pakistan, Switzerland, Tunisia, the United Kingdom and the United States.
The first session of the workshop “Transforming Wheat Breeding Through Integrated Data Management with GOBii and Analysis in Flapjack” benefited breeders from Australia, Canada, Ethiopia, France, India, Ireland, Italy, Morocco, Pakistan, Switzerland, Tunisia, the United Kingdom and the United States.
Susanne Dreisigacker presents during one of the sessions of the workshop.
Susanne Dreisigacker presents during one of the sessions of the workshop.

Powering data analysis around the world

The workshop series, “Transforming Wheat Breeding Through Integrated Data Management with GOBii and Analysis in Flapjack,” aimed to benefit breeders from wheat producing countries all over the world, with sessions over two different time zones spread out over three days to reduce “Zoom fatigue.” Participants joined the first session from Australia, Canada, Ethiopia, France, India, Ireland, Italy, Morocco, Pakistan, Switzerland, Tunisia, the United Kingdom and the United States.

“It was wonderful to see the diversity of participants that we were able to train through an online workshop, many of whom otherwise might not have been able to travel to the UK for the original meeting,” said Jones. “Participants were very engaged, making the workshop so rewarding.”

The workshop was guided by Teresa Saavedra, Wheat Initiative coordinator. Apart from Dreisigacker and Jones, other trainers explained specific tools and approaches. Iain Milne from the James Hutton Institute in Scotland gave more details about the Flapjack genotyping visualization tool, which includes analysis for pedigree verification, marker assisted backcrossing and forward breeding. Andrew Kowalczyk, developer at Diversity Arrays Technology, spoke about the genotyping data QC tool DArTView.

A CIMMYT technician performs one of the steps to extract DNA samples from plants. (Photo: CIMMYT)
A CIMMYT technician performs one of the steps to extract DNA samples from plants. (Photo: CIMMYT)

Clay Sneller, wheat breeder at Ohio State University, contributed training materials for important molecular breeding tools. Carlos Ignacio, previously based at the International Rice Research Center (IRRI) and now working on a PhD in Genomic Selection at Ohio State University, contributed his experience as a GOBii team member and a major contributor towards the design of Flapjack tools. Star Gao, application specialist with GOBii and now a requirements analyst for the Enterprise Breeding System, also facilitated the sessions.

Gilles Charmet, research director at the France’s National Research Institute for Agriculture, Food and Environment (INRAE), introduced the sessions in the Americas/Europe time zone with welcome remarks and overview of the goals of the Wheat Initiative. Alison Bentley, director of the CIMMYT Global Wheat Program, briefed on the achievements and goals of the CIMMYT Wheat program and the Accelerating Genetic Gains in Maize and Wheat for Improved Livelihoods (AGG) project.

“This training will contribute towards us reaching our AGG goals of accelerating gains in wheat, by sharing technical knowledge, and allowing our beneficiary partners to have state-of-the-art know-how in the use of genetic and genomic data,” Bentley said.

Participant Stéphane Boury from Caussade Semences, France commented, “This was a very effective way to learn about new tools in wheat breeding.”

The sessions continue in Australasia next week, and will be introduced by Peter Langridge, chair of the Scientific Board for the Wheat Initiative, and EiB director Michael Quinn. Sanjay Kumar Singh, incoming chair of the Breeding expert working group for the Wheat Initiative, will close the event.

Heat and Drought Wheat Improvement Consortium (HeDWIC)

The Heat and Drought Wheat Improvement Consortium (HeDWIC) is a global research and capacity building network that takes wheat research from the theoretical to the practical by incorporating the best science into real-life breeding scenarios.

By harnessing the latest technologies in crop physiology, genetics and breeding, HeDWIC makes it easier for wheat scientists to work together on solutions to the complex problems of heat and drought adaptation, contributing to the development of new, climate-resilient wheat varieties for farmers. HeDWIC-associated scientists examine current breeding material and collections held in germplasm banks and apply genomic and phenomic tools to identify novel diversity for heat, drought adaptative traits. This results in novel pre-bred lines in terms of genetic diversity for key stress-adaptive traits suitable for use in breeding programs and/or re-selection as cultivars.

The consortium delivers these lines to public and private wheat programs worldwide via the International Wheat Improvement Network (IWIN) — coordinated for more than half a century by the International Maize and Wheat Improvement Center (CIMMYT) — as international public goods whose global impacts are well documented. Through PhD sponsorships and other opportunities for involvement in research, HeDWIC also provides hands-on training to young scientists, preparing a new generation of crop experts to tackle the pressing issues of crop adaptation under future climate scenarios.

HeDWIC adds value to developing more climate-resilient wheat varieties by:

  • Facilitating global coordination of wheat research related to heat and drought stress in partnership with the Wheat Initiative.
  • Developing research and breeding technologies in response to the priorities of stakeholders: researchers, breeders, farmers, seed companies, national programs, and funding organizations.
  • Connecting geographically and agro-climatically diverse sites for rigorous testing of promising concepts.
  • Curating data resources for use by the global wheat research community.
  • Accelerating the deployment of new knowledge and strategies for developing more climate resilient wheat.
  • Preparing a new generation of promising young scientists from climate-affected regions to tackle crop improvement challenges faced by their own countries.
  • Building additional scientific capacity of wheat researchers in a coordinated fashion that enables a faster response to productivity threats associated with climate change.
  • Enabling farmers to adapt to wheat production in a hotter and drier climate faster due to the coordinated effort and synergy lent by HeDWIC.

HeDWIC is directly funded by the Foundation for Food and Agriculture Research (FFAR) and is supported by in-kind contributions from IWIN, the Bill & Melinda Gates Foundation/UK Foreign, Commonwealth and Development Office (FCDO)-funded Accelerating Genetic Gains in Maize and Wheat for Improved Livelihoods (AGG) project, the CGIAR Research Program on Wheat (WHEAT), the International Wheat Yield Partnership, the Wheat Initiative’s AHEAD, and many international partners who support research and capacity building activities through ongoing collaboration.

It also builds on decades of breeding and collaborative research under abiotic stress coordinated by CIMMYT, with support from agencies including Mexico’s Secretariat of Agriculture and Rural Development (SADER), the CGIAR Trust Fund —in particular the Australian Centre for International Agricultural Research (ACIAR), the UK Foreign, Commonwealth and Development Office (FCDO), and the US Agency for International Development (USAID) — Australia’s Grains Research Development Corporation (GRDC), Germany’s Ministry of Agriculture (BMEL), the Bill & Melinda Gates Foundation, the US Department of Agriculture (USDA), and others.

FFAR grant develops climate-resilient wheat

Durum wheat drought tolerance trials in Ciudad Obregon, Mexico, 2017. (Photo: Alfonso Cortés/CIMMYT)
Durum wheat drought tolerance trials in Ciudad Obregon, Mexico, 2017. (Photo: Alfonso Cortés/CIMMYT)

Wheat constitutes 20% of all calories and protein consumed, making it a cornerstone of the human diet, according to the United Nations. However, hotter and drier weather, driven by a changing climate, threatens the global wheat supply. To address this threat, the Foundation for Food and Agriculture Research (FFAR) awarded a $5 million grant to the International Maize and Wheat Improvement Center (CIMMYT) to develop climate-resilient wheat. CIMMYT leads global research programs on maize and wheat, sustainable cropping systems and policies to improve farmers’ livelihoods. These activities have driven major gains in wheat variety improvement across the globe for decades; in the US alone, for example, over 50% of the wheat acreage is sown with CIMMYT-related varieties.

Wheat is among the most widely grown cereal crops in the world and the third-largest crop grown in the US by acre. Nearly all US wheat crops are improved and supported by public agriculture research. As most wheat in the US is dependent on rainfall and has no access to irrigation, this research is critical for helping the plants — and producers — weather climatic changes including extreme heat and drought. Additionally, the demand for wheat is expected to rise in the coming years — as much as 60% by 2050. Without public research, wheat production could decrease by nearly 30% over the same period due to extreme climate conditions.

“FFAR leverages public agriculture research funding through public-private partnerships to pioneer actionable research. With temperatures on the rise and water becoming scarcer, we are committed to supporting wheat farmers and providing new wheat varieties designed with future environmental challenges in mind,” said FFAR’s Executive Director Sally Rockey.

Using the FFAR grant, CIMMYT researchers are pioneering wheat breeding technologies to produce heat-tolerant, drought-resistant and climate-resilient wheat.

CIMMYT researchers and collaborators are applying cutting-edge approaches in genomics, remote sensing and big data analysis to develop new breeding technologies. A key intervention will explore the vast and underutilized reserve of wheat genetic resources to fortify the crop against current and future climate-related stresses.

“This project will help bridge a longstanding gap between state-of-the-art technological findings and crop improvement to deliver climate resilient wheat to farmers as quickly as possible,” said Matthew Reynolds, head of Wheat Physiology at CIMMYT and principal investigator of the project.

Breakthroughs from the FFAR funded project will achieve impact for growers via the International Wheat Improvement Network (IWIN) that supplies new wheat lines to public and private breeding programs worldwide, and has boosted productivity and livelihoods for wheat farmers for over half a century, especially in the Global South.

The research and breeding supported by FFAR will be conducted under the Heat and Drought Wheat Improvement Consortium (HeDWIC), a project led by CIMMYT in partnership with experts across the globe, designed to ensure wheat’s long-term climate resilience. Under the umbrella of the Wheat Initiative’s AHEAD unit, the most relevant advances in academia will be channeled to HeDWIC to help further boost impacts.

“‘Heat,’ ‘drought’ and ‘wheat’ are three of the most important words for billions of people,” said CIMMYT Interim Deputy Director for Research Kevin Pixley. “This partnership between CIMMYT and FFAR will help ensure that the best agricultural science is applied to sustainably raise production of one of the world’s most important staple crops, despite unprecedented challenges.”

CIMMYT Director General Martin Kropff said, “This project represents not only a breakthrough to develop wheat for the future, but also an emerging partnership between CIMMYT and FFAR. I look forward to a productive collaboration that will move us all closer to our mission of maize and wheat science for improved livelihoods.”

FFAR’s investment was matched by co-investments from the CGIAR Research Program on Wheat (WHEAT) and Accelerating Genetic Gains for Maize and Wheat (AGG), a project which is jointly funded by  the Bill & Melinda Gates Foundation and the UK Foreign, Commonwealth, and Development Office (FCDO).


FOR MORE INFORMATION, OR TO ARRANGE INTERVIEWS, CONTACT:

Marcia MacNeil, Communications Officer, CGIAR Research Program on Wheat, CIMMYT. +52 5951148943, m.macneil@cgiar.org

Brian Oakes, FFAR. +1 202-604-5756, boakes@foundationfar.org

About the Foundation for Food & Agriculture Research

The Foundation for Food & Agriculture Research (FFAR) builds public-private partnerships to fund bold research addressing big food and agriculture challenges. FFAR was established in the 2014 Farm Bill to increase public agriculture research investments, fill knowledge gaps and complement USDA’s research agenda. FFAR’s model matches federal funding from Congress with private funding, delivering a powerful return on taxpayer investment. Through collaboration and partnerships, FFAR advances actionable science benefiting farmers, consumers and the environment.

Connect: @FoundationFAR | @RockTalking

About CIMMYT

The International Maize and Wheat Improvement Center (CIMMYT) is the global leader in publicly-funded maize and wheat research and related farming systems. Headquartered near Mexico City, CIMMYT works with hundreds of partners throughout the developing world to sustainably increase the productivity of maize and wheat cropping systems, thus improving global food security and reducing poverty. CIMMYT is a member of the CGIAR System and leads the CGIAR Research Programs on Maize and Wheat and the Excellence in Breeding Platform. The Center receives support from national governments, foundations, development banks and other public and private agencies.

For more information, visit staging.cimmyt.org

Improved metrics for better decisions

By adopting best practices and established modern tools, national agricultural research systems (NARS) are making data-driven decisions to boost genetic improvement. And they are measuring this progress through tracking and setting goals around “genetic gain.”

Genetic gain means improving seed varieties so that they have a better combination of genes that contribute to desired traits such as higher yields, drought resistance or improved nutrition. Or, more technically, genetic gain measures, “the expected or realized change in average breeding value of a population over at least one cycle of selection for a particular trait of index of traits,” according to the CGIAR Excellence in Breeding (EiB)’s breeding process assessment manual.

CGIAR breeders and their national partners are committed to increasing this rate of improvement to at least 1.5% per year. So, it has become a vital and universal high-level key performance indicator (KPI) for breeding programs.

“We are moving towards a more data-driven culture where decisions are not taken any more based on gut feeling,” EiB’s Eduardo Covarrubias told nearly 200 NARS breeders in a recent webinar on Enhancing and Measuring Genetic Gain. “Decisions that can affect the sustainability and the development of organization need to be based on facts and data.”

Improved metrics. Better decisions. More and better food. But how are NARS positioned to better measure and boost the metric?

EiB researchers have been working with both CGIAR breeding programs and NARS to broaden the understanding of genetic gain and to supply partners with methods and tools to measure it.

The recent webinar, co-sponsored by EiB and the CIMMYT-led Accelerating Genetic Gains in Maize and Wheat (AGG) project, highlighted tools and services that NARS are accessing, such as genotyping, data analysis and mechanization.

Through program assessments, customized expert advice, training and provision of services and resources, EiB researchers are helping national partners arrive at the best processes for driving and measuring genetic gains in their programs.

For example, the EiB team, through Crops to End Hunger (CtEH), is providing guidelines to breeders to help them maximize the accuracy and precision, while reducing the cost of calculating genetic gains. The guidelines make recommendations such as better design of trials and implementing an appropriate check strategy that permits regular and accurate calculation of genetic gain.

A comprehensive example at the project level is EiB’s High-Impact Rice Breeding in East and West Africa (Hi-Rice), which is supporting the modernization of national rice programs in eight key rice-producing countries in Africa. Hi-Rice delivers training and support to modernize programs through tools such as the use of formalized, validated product profiles to better define market needs, genotyping tools for quality control, and digitizing experiment data to better track and improve breeding results. This is helping partners replace old varieties of rice with new ones that have higher yields and protect against elements that attack rice production, such as drought and disease. Over the coming years, EiB researchers expect to see significant improvements in genetic gain from the eight NARS program partners.

And in the domain of wheat and maize, AGG is working in 13 target countries to help breeders adopt best practices and technologies to boost genetic gain. Here, the EiB team is contributing its expertise in helping programs develop their improvement plans — to map out where, when and how programs will invest in making changes.

NARS and CGIAR breeding programs also have access to tools and expertise on adopting a continuous improvement process — one that leads to cultural change and buy-in from leadership so that programs can identify problems and solve them as they come up. Nearly 150 national breeding partners attended another EiB/AGG webinar highlighting continuous improvement key concepts and case studies.

National programs are starting to see the results of these partnerships. The Kenya Agricultural & Livestock Research Organization (KALRO)’s highland maize breeding program has undertaken significant changes to its pipelines. KALRO carried out its first-ever full program costing, and based on this are modifying their pipeline to expand early stage testing. They are also switching to a double haploid breeding scheme with support from the CGIAR Research Program on Maize (MAIZE), in addition to ring fencing their elite germplasm for future crosses.

KALRO has also adopted EiB-supported data management tools, and are working with the team to calculate past rates of genetic gains for their previous 20 years of breeding. These actions — and the resulting data — will help them decide on which tools and methods to adopt in order to improve the rate of genetic gain for highland maize.

“By analyzing historical genetic gain over the last 20 years, it would be interesting to determine if we are still making gains or have reached a plateau,” said KALRO’s Dickson LIgeyo, who presented a Story of Excellence at EiB’s Virtual Meeting 2020. “The assessment will help us select the right breeding methods and tools to improve the program.”

Other NARS programs are on a similar path to effectively measure and increase genetic gain. In Ghana, the rice breeding program at Council for Scientific and Industrial Research (CSIR) have developed product profiles, identified their target market segments, costed out their program, digitized their operations, and have even deployed molecular markers for selection.

With this increased expertise and access to tools and services, national breeding programs are set to make great strides on achieving genetic gain goals.

“NARS in Africa and beyond have been aggressively adopting new ideas and tools,” says EiB’s NARS engagement lead Bish Das. “It will pay a lot of dividends, first through the development of state-of-the-art, and ultimately through improving genetic gains in farmers’ fields. And that’s what it’s all about.”