Researchers present highlights from 40 years of collaboration on wheat genomics, breeding for disease resistance and quality improvement.
This article by Emma Orchardson was originally posted on the CIMMYT website.
Global wheat production is currently facing great challenges, from increasing climate variation to occurrence of various pests and diseases. These factors continue to limit wheat production in a number of countries, including China, where in 2018 unseasonably cold temperatures resulted in yield reduction of more than 10% in major wheat growing regions. Around the same time, Fusarium head blight spread from the Yangtze region to the Yellow and Huai Valleys, and northern China experienced a shortage of irrigated water.
In light of these ongoing challenges, international collaboration, as well as the development of new technologies and their integration with existing ones, has a key role to play in supporting sustainable wheat improvement, especially in developing countries. The International Maize and Wheat Improvement Center (CIMMYT) has been collaborating with China on wheat improvement for over 40 years, driving significant progress in a number of areas.
Notably, a standardized protocol for testing Chinese noodle quality has been established, as has a methodology for breeding adult-plant resistance to yellow rust, leaf rust and powdery mildew. More than 330 cultivars derived from CIMMYT germplasm have been released in the country and are currently grown over 9% of the Chinese wheat production area, while physiological approaches have been used to characterize yield potential and develop high-efficiency phenotyping platforms. The development of climate-resilient cultivars using new technology will be a priority area for future collaboration.
In a special issue of Frontiers of Agricultural Science and Engineering focused on wheat genetics and breeding, CIMMYT researchers present highlights from global progress in wheat genomics, breeding for disease resistance, as well as quality improvement, in a collection of nine review articles and one research article. They emphasize the significance of using new technology for genotyping and phenotyping when developing new cultivars, as well as the importance of global collaboration in responding to ongoing challenges.
In a paper on wheat stem rust, CIMMYT scientists Sridhar Bhavani, David Hodson, Julio Huerta-Espino, Mandeep Randawa and Ravi Singh discuss progress in breeding for resistance to Ug99 and other races of stem rust fungus, complex virulence combinations of which continue to pose a significant threat to global wheat production. The authors detail how effective gene stewardship and new generation breeding materials, complemented by active surveillance and monitoring, have helped to limit major epidemics and increase grain yield potential in key target environments.
In the same issue, an article by Caiyun Lui et al. discusses the application of spectral reflectance indices (SRIs) as proxies to screen for yield potential and heat stress, which is emerging in crop breeding programs. The results of a recent study, which evaluated 287 elite lines, highlight the utility of SRIs as proxies for grain yield. High heritability estimates and the identification of marker-trait associations indicate that SRIs are useful tools for understanding the genetic basis of agronomic and physiological traits.
As part of the Delivering Genetic Gain in Wheat (DGGW) project, the International Maize and Wheat Improvement Center (CIMMYT) in collaboration with Kenya Agricultural & Livestock Research Organization (KALRO) and Cornell University recently trained 24 researchers (8 women & 16 men) from 9 countries across the world on wheat rust disease diagnosis and germplasm evaluation. The training took place on October 5-13, 2019 at the KALRO research station in Njoro, Kenya, where CIMMYT’s wheat breeding and rust screening facility is located.
Hands-on skills for efficient breeding and
has held such hands-on trainings annually since 2009, benefitting over 220
scientists, mostly wheat breeders and pathologists from national programs of
developing countries worldwide.
aim at nurturing the next generation of wheat scientists in the different wheat
growing areas, harmonizing cost-effective wheat breeding techniques and
building a global community of practice, so important for our future food
security,’’ said training coordinator, Mandeep Randhawa, Wheat Breeder and
Wheat Rust Pathologist based at CIMMYT Kenya. Dr. Randhawa manages overall
activities of the stem rust phenotyping platform Njoro.
The training focuses particularly on studying resistance to rapidly evolving fungal diseases like black (stem), yellow (stripe) and brown (leaf) rusts. CIMMYT’s Global Wheat Program in Africa uses such trainings to establish new partnerships and continue efforts in wheat breeding and combating emerging challenges across the different farming regions.
The participants learned how to record stem rust field notes to identify different types and levels of resistance, and the interaction with wheat experts helped them better understand how wheat rust pathogens keep evolving. Continuous breeding of wheat varieties with not-only high yield potential but with resistance to rust and non-rust diseases was emphasized.
An important skill the trainees gained during the course was to visually identify and score stem rust symptoms accurately. The percentage of rust coverage on the stem is used to score plants’ susceptibility, e.g. moderately susceptible (MS) or moderately resistant (MR) host reactions to infection.
the way wheat breeders score stem rust severity in different countries like
Ethiopia or Bangladesh is very important, so we could compare research data in
any global breeding program like DGGW and for disease surveillance systems,’’
explained Emeritus Professor Robert McIntosh, one of the trainers from the
Plant Breeding Institute-Cobbitty, University of Sydney, Australia.
its importance to the global food and nutrition security, wheat remains susceptible
to very destructive rust diseases. Rusts can lead to total crop failure when
the climate conditions are favorable for the fungus and varieties grown by
farmers are susceptible. The wheat scientific community has to remain vigilant
on rust outbreaks globally as these pathogens evolve quickly. The stem rust
race Ug99, reported for the first time in Uganda in 1999, was able to overcome
the stem rust resistance gene Sr31 present in many popular varieties
planted by farmers in the region. In 2013-14, wheat variety Digalu in Ethiopia and
Robin in Kenya became susceptible to a new stem rust race with virulence to
gene Srtmp. By 2019, fourteen
different races in Ug99 lineage have been identified across Eastern and
“You can train someone for one year to score for rust resistance, but you
learn all your life,’’ added McIntosh. “In
the era of molecular breeding, it is remarkable to see that visual phenotyping
recognition still plays a strong role in safeguarding one of the most important
“This is the first time
I am doing this rust scoring. This will be important for my job of certifying
new rust resistant wheat varieties, to know how to rank one wheat variety from
other popular check,’’ noted seed health inspector, Philip Chemeltorit from the
Kenya Plant Health Inspectorate Services (KEPHIS) Nakuru. A durum wheat breeder,
Ms. Divya Ambati from Indore, India learned how the rust symptoms vary between
durum and bread wheat germplasm, while wheat scientists, Ms. Sourour Ayed and
Ms. Rifka Hammami, from Tunisia were more interested in how to tackle Septoria,
another fungal disease prevalent in their country.
training course is a great opportunity for national programs to have first-hand
information on the performance of their varieties and advanced lines evaluated
at the phenotyping platform from respective countries. It is important to
understand the different types of resistance that can be used in breeding. Strategies
of combining different race specific and adult plant resistance (APR) genes is
important for researchers to develop varieties with durable resistance,” said
Sridhar Bhavani, Head of Wheat Rust Pathology at CIMMYT Mexico.
Back to the breeder’s equation
and distributing rust resistant wheat varieties is regarded as the most
cost-effective and eco-friendly control measure, especially in developing
countries, where the majority are resource-poor smallholder farmers with limited
access to fungicides to control the disease.
Ravi Singh, Head of Wheat
Improvement at CIMMYT Mexico explained the new wheat breeding priorities, where
breeders should focus on cost-effectiveness:
‘’Wheat scientists must
go back to the blackboard how to increase genetic gains in a cost-effective
way. What new methods and tools would increase the number of lines screened
(intensity), with good accuracy and shorter breeding cycles?’’
CIMMYT Mexico for
instance has just invested in a new large field greenhouse in Toluca research
station to produce four generations of wheat annually, instead of two
currently. The global wheat program will be more responsive to new pests and
disease like the recent wheat blast outbreak that affected Bangladesh.
‘’But not all is about
speed breeding,’’ warned Singh. “The wheat research should remain holistic and
continue asking the right questions to well capture farmers and wheat
processors’ needs when defining future breeding targets or product profiles.
Wheat yield potential remain very important, but you have to ‘package other
traits like water-use efficiency, disease resistance, nutrition, profitability
Godwin Macharia, Centre Director and Wheat Breeder of the
KALRO- Njoro Centre discussed progress in wheat improvement through
Kenya Kasuku and Kenya Jacana with significant yield advantage over current
commercial varieties and moderate levels of resistance to stem rust were
released by KEPHIS in 2019. Moreover, several high-yielding rust resistant
wheat lines are in the national performance testing towards identification and
release of suitable varieties for commercialization in Kenya growing
environments. Seed multiplication is in process with enough volumes of breeder
seed of the new varieties available for further bulking and distribution to
growers for cultivation in the 2020 season.’’
We live in an era that calls for large-scale social and environmental transformation. But society has taken only meager steps towards producing the unprecedented changes needed to achieve the Sustainable Development Goals. Those of us working on sustainable rural development understand that we face enormous challenges: from ending hunger and improving nutrition, to preserving vital ecosystems, tackling climate change, empowering women and ending poverty. But we are still caught up in a 20th century paradigm that sees the world as a logical, linear, technology-centric system. This approach has hardly worked in the past, and it will certainly fail in the future. We need to change the underlying system. We need a new way of working.
In a new paper, my colleagues and I at the International Maize and Wheat Improvement Center (CIMMYT) joined up with development experts to argue that agricultural development projects should stop focusing narrowly on changing farming conditions within a specific project context. For too long, the dominant approach has been to develop new agricultural practices and technologies, prove that they work, spread them to a few hundred farmers through controlled pilot projects, and then hope this is enough to convince governments, industry and millions of smallholder farmers to do things differently. This is akin to inventing the mobile phone but ignoring the need for electricity, cellular towers, network providers, or any of the other supporting elements that enable the use of the phone.
Instead, we argue that projects should be seen as vehicles for changing the underlying system that enables a technology to be successfully used by millions. This means acknowledging and engaging with the complex array of real-world elements that comprise these systems, such as infrastructure, market forces, politics, people and power relationships. We do not suggest that project implementers become experts in all of these things, but rather that they need to take them into account when developing scalable solutions, by studying the best scaling process for a particular context, and positioning their contributions within that wider context.
We need to change course and embrace new attitudes, new skills and new ways of collaborating if we want to produce sustainable systems change at scale. And one important part of this process involves reconsidering our approach to pilot programs.
Pilots never fail, pilots never scale Most pilots test whether an innovation works in a particular context. We liken this to building a greenhouse (a controlled environment) within a landscape (the real world). Pilot projects rely heavily on external resources and expertise, and are shielded from real world challenges like politics, regulations, market forces and finance. A crucial feature of pilot programs, and a key limitation, is that they don’t face the same pressure as actual programs to reach as many people as possible within a limited timeframe. That means they aren’t generating important lessons about the conditions needed to enable sustainable long-term adoption.
As a result, when the time comes to scale up a successful pilot project, we generally take one of two paths:
One path involves building a bigger greenhouse, which means expanding the controlled environment by doing more of the same with more money. But this approach is expensive, and unlikely to produce lasting change. The expanded project may indeed reach an impressive number of households, but this is no guarantee that they can and will continue to use a technology after the project ends. And this also doesn’t guarantee that adoption will spread.
The other conventional approach to scaling a pilot program is to simply remove the greenhouse and assume the innovation is so good that it will spontaneously scale itself. But as any gardener knows, a plant will not easily survive under real conditions once a greenhouse is removed. Likewise, farming communities are unlikely to continue using a new practice or technology if the surrounding system remains unchanged, since it is this very system that shaped their conventional way of farming.
Steps for achieving large scale – and lasting – change So what would a more effective approach to scale look like? We reviewed decades of experience and insights from a number of sectors, including agriculture, health, education, nutrition and urban planning. We identified the following strategies that can help rural development projects change their approach towards achieving impact:
Adopt a new mindset: Understand that overlapping economic social, technical and political systems shape peoples’ choices and behaviors. Recognize the stakeholder dynamics that determine the present situation. You need to understand the key players and rules of the game in order to engage with – and influence – them.
Design for scale from the start: Asking “Does the pilot project work?” is not enough. Start by asking “What happens beyond the pilot project, if it works?” Then work with strategic local partners that are willing and able to provide public/private funding and leadership to sustain the initiative once the pilot project ends. But keep in mind: This also means considering – and planning for – the unintended consequences that come along with big change initiatives.
Clarify your role: Scaling means intervening into a range of elements within a system, and implementing institutions need to recognize their strengths and limitations in doing so. If they find that they lack any key capabilities that could reduce a program’s effectiveness, they should collaborate strategically with others to better influence the many different parts of the system.
See pilots as building blocks: Rather than viewing pilot projects as distinct entities, see them as part of a bigger ecology of initiatives to achieve long-term change – for example, as elements of a sector or country development strategy, or of other emerging market-led initiatives.
The global agricultural development community is starting to come to grips with this new mindset and way of working. For instance, in Zimbabwe, CIMMYT and its partners are taking a fresh approach to encouraging small-scale farm mechanization. We are working on strengthening a wide range of functions that are needed to support a market for two-wheeled tractors. This includes creating demand for machinery among local smallholders through farmer-to-farmer demonstrations, field days and ICT solutions. The initiative also offers technical and business development training to service providers, mechanics, artisans and manufacturers, and develops the capacity of existing vocational training centers to provide ongoing machinery trainings. Private sector partners can access valuable insights and intelligence on the performance of different machines and their costs and benefits, and can also access profiles of potential customers, thus spurring demand. And aspiring service providers are connected to financial institutions that can provide loans for machinery purchase. This approach goes far beyond the typical technology-oriented pilot project, and shows the positive steps being taken to engage with, and ultimately disrupt, the different elements of the underlying system.
Pilot projects last 2-4 years, but scaling a successful pilot to national application can take 15 years. While we are seeing more initiatives move away from the technology transfer mindset focused only on products, end users and numbers, and towards a more systems-focused approach, critical mass is a long way off. Agricultural development organizations and their funders need to urgently change course and position themselves as key players in changing the system at scale, rather than pushing an innovation into the rigid, incumbent system. This requires linking up with the right partners on the ground, who can help make this broader approach to sustainable development into the “new normal.”
Acknowledgments: This work was funded by the CGIAR Research Programs MAIZE (www.maize.org) and WHEAT (www.wheat.org) coordinated by the International Maize and Wheat Improvement Center (CIMMYT) in Mexico. The authors worked in collaboration with Management Systems International (MSI) and the PPPLab (supported by the Directorate General for International Cooperation (DGIS) and SNV Netherlands Development Organization). The German Federal Ministry for Economic Cooperation and Development (BMZ) supported the work through the Integrated Expert program of Gesellschaft fuer Internationale Zusammenarbeit (GIZ) GmbH. Any opinions, findings, conclusion, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of CRP MAIZE, CRP WHEAT, GIZ, DGIS or SNV.
The world urgently needs a transformation of the global food system, leading to healthier diets for all and a drastic reduction in agriculture’s environmental impact. The major cereal grains must play a central role in this new revolution for the benefit of the world’s poorest people.
Pioneering research on our three most important cereal grains — maize, rice, and wheat — has contributed enormously to global food security over the last half century, chiefly by boosting the yields of these crops and by making them more resilient in the face of drought, flood, pests and diseases. But with more than 800 million people still living in chronic hunger and many more suffering from inadequate diets, much remains to be done. The challenges are complicated by climate change, rampant degradation of the ecosystems that sustain food production, rapid population growth and unequal access to resources that are vital for improved livelihoods.
In recent years, a consensus has emerged among agricultural researchers and development experts around the need to transform global food systems, so they can provide healthy diets while drastically reducing negative environmental impacts. Certainly, this is a central aim of CGIAR — the world’s largest global agricultural research network — which views enhanced nutrition and sustainability as essential for achieving the Sustainable Development Goals. CGIAR scientists and their many partners contribute by developing technological and social innovations for the world’s key crop production systems, with a sharp focus on reducing hunger and poverty in low- and middle-income countries of Africa, Asia and Latin America.
The importance of transforming food systems is also the message of the influential EAT-Lancet Commission report, launched in early 2019. Based on the views of 37 leading experts from diverse research disciplines, the report defines specific actions to achieve a “planetary health diet,” which enhances human nutrition and keeps the resource use of food systems within planetary boundaries. While including all food groups — grains, roots and tubers, pulses, vegetables, fruits, tree nuts, meat, fish, and dairy products — this diet reflects important shifts in their consumption. The major cereals, for example, would supply about one-third of the required calories but with increased emphasis on whole grains to curb the negative health effects of cheap and abundant supplies of refined cereals.
This proportion of calories corresponds roughly to the proportion of its funding that CGIAR currently invests in the major cereals. These crops are already vital in diets, cultures, and economies across the developing world, and the way they are produced, processed and consumed must be a central focus of global efforts to transform food systems. There are four main reasons for this imperative.
1. Scale and economic importance
The sheer extent of major cereal production and its enormous value, especially for the poor, account in large part for the critical importance of these crops in global food systems. According to 2017 figures, maize is grown on 197 million hectares and rice on more than 167 million hectares, mainly in Asia and Africa. Wheat covers 218 million hectares, an area larger than France, Germany, Italy, Spain and the UK combined. The total annual harvest of these crops amounts to about 2.5 billion tons of grain.
Worldwide production had an estimated annual value averaging more than $500 billion in 2014-2016. The prices of the major cereals are especially important for poor consumers. In recent years, the rising cost of bread in North Africa and tortillas in Mexico, as well as the rice price crisis in Southeast Asia, imposed great hardship on urban populations in particular, triggering major demonstrations and social unrest. To avoid such troubles by reducing dependence on cereal imports, many countries in Africa, Asia and Latin America have made staple crop self-sufficiency a central element of national agriculture policy.
2. Critical role in human diets
Cereals have a significant role to play in food system transformation because of their vital importance in human diets. In developing countries, maize, rice, and wheat together provide 48% of the total calories and 42% of the total protein. In every developing region except Latin America, cereals provide people with more protein than meat, fish, milk and eggs combined, making them an important protein source for over half the world’s population.
Yellow maize, a key source of livestock feed, also contributes indirectly to more protein-rich diets, as does animal fodder derived from cereal crop residues. As consumption of meat, fish and dairy products continues to expand in the developing world, demand for cereals for food and feed must rise, increasing the pressure to optimize cereal production.
In addition to supplying starch and protein, the cereals serve as a rich source of dietary fiber and nutrients. CGIAR research has documented the important contribution of wheat to healthy diets, linking the crop to reduced risk of type 2 diabetes, cardiovascular disease, and colorectal cancer. The nutritional value of brown rice compared to white rice is also well known. Moreover, the recent discovery of certain genetic traits in milled rice has created the opportunity to breed varieties that show a low glycemic index without compromising grain quality.
The major cereals have undergone further improvement in nutritional quality during recent years through a crop breeding approach called “biofortification,” which boosts the content of essential vitamins or micronutrients. Dietary deficiencies of this kind harm children’s physical and cognitive development, and leave them more vulnerable to disease. Sometimes called “hidden hunger,” this condition is believed to cause about one-third of the 3.1 million annual child deaths attributed to malnutrition. Diverse diets are the preferred remedy, but the world’s poorest consumers often cannot afford more nutritious foods. The problem is especially acute for women and adolescent girls, who have unequal access to food, healthcare and resources.
It will take many years of focused effort before diverse diets become a reality in the lives of the people who need them most. Diversified farming systems such as rice-fish rotations that improve nutritional value, livelihoods and resilience are a step in that direction. In the meantime, “biofortified” cereal and other crop varieties developed by CGIAR help address hidden hunger by providing higher levels of zinc, iron and provitamin A carotenoids as well as better protein quality. Farmers in many developing countries are already growing these varieties.
A 2018 study in India found that young children who ate zinc-biofortified wheat in flatbread or porridge became ill less frequently. Other studies have shown that consumption of provitamin A maize improves the body’s total stores of this vitamin as effectively as vitamin supplementation. Biofortified crop varieties are not a substitute for food fortification (adding micronutrients and vitamins during industrial food processing). But these varieties can offer an immediate solution to hidden hunger for the many subsistence farmers and other rural consumers who depend on locally produced foods and lack access to fortified products.
4. Wide scope for more sustainable production
Cereal crops show much potential not only for enhancing human heath but that of the environment as well. Compared to other crops, the production of cereals has relatively low environmental impact, as noted in the EAT-Lancet report. Still, it is both necessary and feasible to further enhance the sustainability of cereal cropping systems. Many new practices have a proven ability to conserve water as well as soil and land, and to use purchased inputs (pesticides and fertilizers) far more efficiently. With innovations already available, the amount of water used in current rice cultivation techniques, for example, can be significantly reduced from its present high level.
Irrigation scheduling, laser land leveling, drip irrigation, conservation tillage, precision nitrogen fertilization, and cereal varieties tolerant to drought, flooding and heat are among the most promising options. In northwest India, scientists recently determined that optimal practices can reduce water use by 40%, while maintaining yields in rice-wheat rotations. There and in many other places, the adoption of new practices to improve cereal production in the wet season not only leads to more efficient resource use but also creates opportunities to diversify crop production in the dry season. Improvements to increase cereal crop yields also reduces their environmental footprint; using less land, enhancing carbon sequestration and biodiversity and, for rice, reducing methane emissions per kilo of rice produced. Given the enormous extent of cereals cultivation, any improvement in resource use efficiency will have major impact, while also freeing up vast amounts of land for other crops or natural vegetation.
A major challenge now is to improve access to the knowledge and inputs that will enable millions of farmers to adopt new techniques, making it possible both to diversify production and grow more with less. Another key requirement consists of clear signals from policymakers, especially where land and water are limited, about the priority use of these resources — for example, irrigating low-value cereals to bolster food security versus applying the water to higher value crops and importing staple cereals.
Toward a sustainable dietary revolution
Future-proofing the global food system requires bold steps. Policy and research need to support a double transformation, centered on nutrition and sustainability.
CGIAR works toward nutritional transformation of our food system through numerous global partnerships. We give high priority to improving cereal crop systems and food products, because of their crucial importance for a growing world population. Recognizing that this alone will not suffice for healthy diets, we also strongly promote greater dietary diversity through our research on various staple crops and production systems and by raising public awareness of more balanced and nutritious diets.
To help achieve a sustainability transformation, CGIAR researchers and partners have developed a wide array of techniques that use resources more efficiently, enhance the resilience of food production in the face of climate change and reduce greenhouse gas emissions, while achieving sustainable increases in crop yields. At the same time, we are generating new evidence on which techniques work best under what conditions to target the implementation of these solutions more effectively.
The ultimate impact of our work depends crucially on the growing resolve of developing countries to promote better diets and more sustainable food production through strong policies and programs. CGIAR is well prepared to help strengthen these measures through research for development, and we are confident that our work on cereals, with continued donor support, will have high relevance, generating a wealth of innovations that help drive the transformation of global food systems.
Martin Kropff is the Director General of the International Maize and Wheat Improvement Center (CIMMYT).
Matthew Morell is the Director General of the International Rice Research Institute (IRRI).
Data from microsatellites can be used to detect and double the impact of sustainable interventions in agriculture at large scales, according to a new study led by the University of Michigan (U-M).
By being able to detect the impact and target interventions to locations where they will lead to the greatest increase or yield gains, satellite data can help increase food production in a low-cost and sustainable way.
According to the team of researchers from U-M, the International Maize and Wheat Improvement Center (CIMMYT), and Stanford and Cornell universities, finding low cost ways to increase food production is critical given that feeding a growing population and increasing the yields of crops in a changing climate are some of the greatest challenges of the coming decades.
“Being able to use microsatellite data, to precisely target an intervention to the fields that would benefit the most at large scales will help us increase the efficacy of agricultural interventions,” said lead author Meha Jain, assistant professor at the U-M School for Environment and Sustainability.
Microsatellites are small, inexpensive, low-orbiting satellites that typically weigh 100 kilograms (220 pounds) or less.
“About 60-70% of total world food production comes from smallholders, and they have the largest field-level yield gaps,” said Balwinder Singh, senior researcher at CIMMYT.
To show that the low-cost microsatellite imagery can quantify and enhance yield gains, the researchers conducted their study in smallholder wheat fields in the Eastern Indo-Gangetic Plains in India.
They ran an experiment on 127 farms using a split-plot design over multiple years. In one half of the field, the farmers applied nitrogen fertilizer using hand broadcasting, the typical fertilizer spreading method in this region. In the other half of the field, the farmers applied fertilizer using a new and low-cost fertilizer spreader.
To measure the impact of the intervention, the researchers then collected the crop-cut measures of yield, where the crop is harvested and weighed in field, often considered the gold standard for measuring crop yields. They also mapped field and regional yields using microsatellite and Landsat satellite data.
They found that without any increase in input, the spreader resulted in 4.5% yield gain across all fields, sites and years, closing about one-third of the existing yield gap. They also found that if they used microsatellite data to target the lowest yielding fields, they were able to double yield gains for the same intervention cost and effort.
“Being able to bring solutions to the farmers that will benefit most from them can greatly increase uptake and impact,” said David Lobell, professor of earth system science at Stanford University. “Too often, we’ve relied on blanket recommendations that only make sense for a small fraction of farmers. Hopefully, this study will generate more interest and investment in matching farmers to technologies that best suit their needs.”
The study also shows that the average profit from the gains was more than the amount of the spreader and 100% of the farmers were willing to pay for the technology again.
Jain said that many researchers are working on finding ways to close yield gaps and increase the production of low-yielding regions.
“A tool like satellite data that is scalable and low cost and can be applied across regions to map and increase yields of crops at large scale,” she said.
The study is published in the October issue of Nature Sustainability. Other researchers include Amit Srivastava and Shishpal Poonia of the International Maize and Wheat Improvement Center in New Delhi; Preeti Rao and Jennifer Blesh of the U-M School of Environment and Sustainability; Andrew McDonald of Cornell; and George Azzari and David Lobell of Stanford.
New study provides an extensive field-test validation of existing
genetic markers for thousand grain weight; finds both surprises and promising
To meet the demand for wheat from a rising and quickly
urbanizing population, wheat yields in farmers’ fields must increase by an
estimated 1.5% each year through 2030.
Of all the factors that influence yield, grain weight is the
trait that is most stable and heritable for use in breeding improved wheat
varieties. Breeders measure this by thousand grain weight (TGW).
Over the years, molecular scientists have made efforts to
identify genes related to increased TGW, in order to speed up breeding through
marker-assisted selection (MAS). Using MAS, breeders can select parents that contain
genes related to the traits they are looking for, increasing the likelihood
they will be passed on and incorporated in a new variety.
There have been some limited successes in these efforts: in
the past years, a few genes related to increased TGW have been cloned, and a
set of genetic markers have been determined to be used for MAS. However, the
effects of most of these candidate genes (CGs) have not yet been validated in
diverse sets of wheat germplasm throughout the world that represent the full
range of global wheat growing environments.
A group of wheat geneticists and molecular breeders from the International Maize and Wheat Improvement Center (CIMMYT) has recently conducted a thorough study to confirm the effects of the favorable alleles reported for these genes on TGW in CIMMYT wheat, — and to identify new genetic determinants of this desired trait.
They found some good news and some bad.
First, the good news: focusing on more than 4000 lines of CIMMYT
wheat germplasm they found 15 haplotype blocks significantly associated with
TGW. Four haplotype blocks associated
with TGW were also associated with grain yield – a grand prize for breeders,
because in general the positive
association of grain yield with TGW is less profound and sometimes even
negative. However, of the 14 genes that had been previously reported to
increase TGW, only one in CIMMYT’s 2015-2016 Elite Yield Trial and two in Wheat
Associative Mapping Initiative panel were shown to have significant TGW
The scientists also found that the alleles — pairs of genes
on a chromosome that determine heredity – that were supposedly favorable to TGW
actually decreased it. These candidate
genes also appear to vary in their TGW effects with genetic background and/or
Thus, these findings also provide a foundation for more detailed
investigations, opening the door for more studies on the genetic background
dependence and environment sensitivity of the known candidate genes for
indicate that it will be challenging to use MAS based on these existing markers
across individual breeding programs,” said Deepmala Sehgal, CIMMYT wheat geneticist
and the primary author of the study.
However, efforts to identify new genetic determinants of TGW
were promising. The authors’ study of
CIMMYT germplasm found one locus on chromosome 6A that showed increases of up
to 2.60 grams in TGW and up to 258 kilograms per hectare in grain yield.
This discovery expands opportunities for developing
diagnostic markers to assist in multi-gene pyramiding – a process that can derive
new and complementary allele combinations for enhanced wheat TGW and grain
Most of all, the study highlights the strong need for better
and more validation of the genes related to this and other traits, so that
breeders can be sure they are using material that is confirmed to increase
wheat grain weight and genetic yield.
“Our findings are very promising for future efforts to
efficiently develop more productive wheat in both grain weight and grain yield,”
said Sehgal. “This ultimately means more bread on household tables throughout
“Validation of Candidate Gene-Based Markers
and Identification of Novel Loci for Thousand-Grain Weight in Spring Bread
Wheat” in Frontiers in Plant Science
by Deepmala Sehgal, Suchismita Mondal, Carlos Guzman, Guillermo Garcia Barrios,
Carolina Franco, Ravi Singh and Susanne Dreisigacker was supported by funding
from the CGIAR Research Program on Wheat (WHEAT), the Delivering Genetic Gain
in Wheat (DGGW) project funded by the Bill & Melinda Gates Foundation and the
UK Department for International Development (DFID), and the US Agency for
International Development (USAID) Feed the Future Innovation Lab for Applied
The Norman Borlaug International Agricultural Science and Technology Fellowship Program at Washington State University, sponsored by the U.S. Department of Agriculture, facilitates international collaboration to fight soil borne pathogens
Soil borne pathogens (SBPs) are microorganisms that thrive in the soil and attack cereal crops, notably wheat. They cause high yield losses and reduce grain quality and quantity. SBPs include nematodes, a kind of round worm — including the Heterodera species of cereal cyst nematode and Pratylenchus species of root lesion nematodes — and crown rot caused by the Fusarium species, all of which attack roots of cereal crops. Drought and monoculture farming exacerbate this damage.
chemical, biological and other options can be used to keep pathogen population
levels low, the most environmentally friendly and biologically effective method
of control is through a resistant crop variety.
However, up to now, only a few resistance genes have been identified
against the cereal cyst nematode, Heterodera filipjevi, and this resistance
is not yet present in high yielding cultivars.
For nearly 20 years, research to fight these pathogens has benefited from a productive collaboration between the International Maize and Wheat Improvement Program (CIMMYT) in Turkey and Washington State University (WSU) and the U.S. Department of Agriculture’s Agricultural Research Service (USDA-ARS) in the United States through a fellowship program named after CIMMYT founder and Green Revolution pioneer Norman Borlaug. CIMMYT wheat breeders in Turkey have been working with breeders in Pullman, Washington to find stronger resistance genes to cereal cyst nematodes identify pathotypes, and other research areas that strengthen both CIMMYT and WSU wheat breeding programs.
pathologist and Turkey Country Representative Abdelfattah Dababat has been
working with WSU and USDA-ARS since 2010. Dababat, who joined CIMMYT as a
postdoctoral student studying soil borne pathogens (SBPs) in 2009, recently
spent two months in Pullman as a Norman Borlaug International Agricultural
Science and Technology Fellow, sponsored by the U.S. Department of
Agriculture’s Agricultural Research Service (USDA-ARS). There he was able to
share CIMMYT work with members of the WSU Department of Plant Pathology,
USDA-ARS, exchange ideas with well-known pathologists, and even travel to
Cleveland, Ohio to attend the meeting of the American Phytopathological
experience at WSU has been productive and inspiring.” said Dababat. “I have
learned from some of the best minds in plant pathology, and worked on SBP
issues that plague farmers both in my region and theirs.
like to thank CIMMYT, especially Dr. Hans Braun, for the opportunity to obtain
this great fellowship visit to WSU.”
relationship was strengthened when the two institutions collaborated on a proposal
for an Ethiopian PhD student at the University of Ankara, Turkey to work on
SBPs. Through the sponsorship of a Borlaug Leadership Enhancement in
Agriculture Program (LEAP) scholarship, Elfinesh Shikur Gebremariam spent four
months at WSU in 2013-14 to learn about molecular aspects related to crown rot
diseases. She published three peer-reviewed papers in high impact factor
Paulitz, a research plant pathologist with USDA-ARS and an adjunct professor in
WSU’s Department of Plant Pathology has also been an active member in this
collaboration, contributing to two master classes on soil borne pathogens in
cereals at CIMMYT’s Turkey research station.
Paulitz has made tremendous impact in our region,” said Dababat. “He trained
more than 50 young scientists who are now in a high scientific and or
managerial positions and are contributing not only to their own food security
but also to international food security.”
SBP resistance progress and challenges
screens hundreds of wheat germplasm lines each year against SBPs at its
research station in Eskisehir, Turkey, in collaboration with the Grain Research
Development Corporation of Australia. Using association mapping, CIMMYT
researchers have been able to identify new sources of resistance to cereal cyst
nematodes, and many new lines have been approved as moderately resistant to
resistant compared known varieties. As a
result, hundreds of lines of winter and spring wheat germplasm moderately
resistant to SBPs are available.
cyst nematodes (CCN) are a persistent problem, however. Among the most damaging
nematode pests to small grain cereal production, CCN are common from the Middle
East, North Africa and Central Asia to the Pacific Northwest of the U.S. These
nematodes alone are estimated to reduce production of crops by 10% globally. Breeding for resistance is difficult because
breeders must use live nematodes to phenotype, or measure, the lines, and there
are few molecular markers linked to the resistance genes against the major CCN
species to help identify them.
CIMMYT research — involving targeted genetic exploitations, classical
selection breeding of resistant genotypes discovery of quantitative trait loci
(QTLs) associated with resistance genes, as well as recent genome-wide
association studies (GWAS) to associate nematode resistance or susceptibility
with particular regions of the genome — has seen some success. One important
source for disease-resistance genes is found in wheat’s wild relatives. So far, 11 resistance genes have been
reported. Nine of these were transferred into common wheat from its wild
relatives (like Aegilops or goat
grass, and other Triticum species) to
enhance resistance against the H. avenae
species of nematode.
Recently, CIMMYT and the University of Bonn, Germany performed GWAS on 161 winter wheat accessions and identified 11 QTL associated with resistance against the H. filipjevi species of nematode. These QTLs were intercrossed into susceptible winter wheat germplasm and the first generation material (F1) along with the parents were sent to WSU as part of the Borlaug fellowship. CIMMYT and WSU also conducted several surveys in countries including Azerbaijan and Kazakhstan to detect SBPs in cereals.
research will help both institutes to find stronger resistance genes to the
cereal cyst nematodes.
Washington State-based part of Dababat’s Borlaug fellowship is drawing to a
close, but the collaboration and relationship between the two institutions remains.
In June of next year, Paulitz will visit him in Turkey to follow up on his
international collaboration between CIMMYT and WSU shows how much progress we
can make when we work together,” said Dababat. “I look forwarding to continuing
our partnership to help farmers around the world find resistance to SBPs.”
Scientists identified significant new chromosomal regions for wheat yield and disease resistance, which will speed up global breeding efforts.
This story by Mike Listman was originally posted on CIMMYT.org
Using the full wheat genome map published in 2018, combined with data from field testing of wheat breeding lines in multiple countries, an international team of scientists has identified significant new chromosomal regions for wheat yield and disease resistance and created a freely-available collection of genetic information and markers for more than 40,000 wheat lines.
Reported today in Nature Genetics, the results will speed up global efforts to breed more productive and climate-resilient varieties of bread wheat, a critical crop for world food security that is under threat from rising temperatures, rapidly-evolving fungal pathogens, and more frequent droughts, according to Philomin Juliana, wheat scientist at the International Maize and Wheat Improvement Center (CIMMYT) and first author of the new study.
“This work directly connects the wheat genome reference map with wheat lines and extensive field data from CIMMYT’s global wheat breeding network,” said Juliana. “That network in turn links to over 200 breeding programs and research centers worldwide and contributes to yield and other key traits in varieties sown on nearly half the world’s wheat lands.”
The staple food for more than 2.5 billion people, wheat provides 20% of human dietary calories and protein worldwide and is critical for the nutrition and food security of hundreds of millions of poor persons in regions such as North Africa and South Asia.
“Farmers and societies today face new challenges to feed rising and rapidly-urbanizing populations, and wheat epitomizes the issues,” said Ravi Singh, CIMMYT wheat breeder and corresponding author of the study. “Higher temperatures are holding back yields in major wheat-growing areas, extreme weather events are common, crop diseases are spreading and becoming more virulent, and soil and water are being depleted.”
Juliana said the study results help pave the way to apply genomic selection, an approach that has transformed dairy cow husbandry, for more efficient wheat breeding.
“Molecular markers are getting cheaper to use; meanwhile, it’s very costly to do field testing and selection involving many thousands of wheat plants over successive generations,” Juliana said. “Genome-wide marker-based selection can help breeders to precisely identify good lines in early breeding generations and to test plantlets in greenhouses, thereby complementing and streamlining field testing.”
The new study found that genomic selection could be particularly effective in breeding for wheat end-use quality and for resistance to stem rust disease, whose causal pathogen has been evolving and spreading in the form of highly-virulent new races.
The new study also documents the effectiveness of the global public breeding efforts by CIMMYT and partners, showing that improved wheat varieties from this work have accumulated multiple gene variants that favor higher yields, according to Hans-Joachim Braun, director of CIMMYT’s global wheat program.
“This international collaboration, which is the world’s largest publicly-funded wheat breeding program, benefits farmers worldwide and offers high-quality wheat lines that are released directly to farmers in countries, such as Afghanistan, that are unable to run a full-fledged wheat breeding program,” Braun explained.
The study results are expected to support future gene discovery, molecular breeding, and gene editing in wheat, Braun said.
Together with more resource-efficient cropping systems, high-yielding and climate-resilient wheat varieties will constitute a key component of the sustainable intensification of food production described in Strategy 3 of the recent EAT-Lancet Commission recommendations to transform the global food system. Large-scale genomics will play a key role in developing these varieties and staying ahead of climate- and disease-related threats to food security.
Funders of this work include USAID’s Feed the Future Innovation Lab for Applied Wheat Genomics. Contributing to the research described are research teams engaged in wheat improvement at CIMMYT, and the lab of Jesse Poland, Associate Professor at Kansas State University and Director of the USAID Applied Wheat Genomics Innovation Lab.
New research shows that smallholder farmers in Ethiopia used various coping mechanisms apart from fungicides in response to the recent wheat rust epidemics in the country. Scientists from the International Maize and Wheat Improvement Center (CIMMYT) and the Ethiopian Institute of Agricultural Research (EIAR) call for continuous support to research and extension programs to develop and disseminate improved wheat varieties with resistant traits to old and newly emerging rust races.
Rising wheat yields cannot catch up rising demand
Wheat is the fourth largest food crop in Ethiopia cultivated by smallholders, after teff, maize and sorghum. Ethiopia is the largest wheat producer in sub-Saharan Africa and average farm yields have more than doubled in the past two decades, reaching 2.74 tons per hectare on average in 2017/18. Farmers who use improved wheat varieties together with recommended agronomic practices recorded 4 to 6 tons per hectare in high-potential wheat growing areas such as the Arsi and Bale zones. Yet the country remains a net importer because demand for wheat is rapidly rising.
The Ethiopian government has targeted wheat self-sufficiency by 2023 and the country has huge production potential due to its various favorable agroecologies for wheat production.
However, one major challenge to boosting wheat production and yields is farmers’ vulnerability to rapidly evolving wheat diseases like wheat rusts.
The Ethiopian highlands have long been known as hot spots for stem and yellow wheat rusts caused by the fungus Puccinia spp., which can spread easily under favorable climatic conditions. Such threats may grow with a changing climate.
Recurrent outbreaks of the two rusts destroyed significant areas of popular wheat varieties. In 2010, a yellow rust epidemic severely affected the popular Kubsa variety. In 2013/14, farmers in the Arsi and Bale zones saw a new stem rust race destroy entire fields of the bread wheat Digalu variety.
In response to the 2010 yellow rust outbreak, the government and non-government organizations, seed enterprises and other development supporters increased the supply of yellow rust resistant varieties like Kakaba and Danda’a.
Fungicide is not the only solution for wheat smallholder farmers
Two household panel surveys during the 2009/10 main cropping season, before the yellow rust epidemic, and during the 2013/14 cropping season analyzed farmers’ exposure to wheat rusts and their coping mechanisms. From the survey, 44% of the wheat farming families reported yellow rust in their fields during the 2010/11 epidemic.
Household data analysis looked at the correlation between household characteristics, their coping strategies against wheat rust and farm yields. The study revealed there was a 29 to 41% yield advantage by increasing wheat area of the new, resistant varieties even under normal seasons with minimum rust occurrence in the field. Continuous varietal development in responding to emerging new rust races and supporting the deployment of newly released rust resistant varieties could help smallholders cope against the disease and maintain improved yields in the rust prone environments of Ethiopia.
The case study showed that apart from using fungicides, increasing wheat area under yellow rust resistant varieties, increasing diversity of wheat varieties grown, or a combination of these strategies were the main coping mechanisms farmers had taken to prevent new rust damages. Large-scale replacement of highly susceptible varieties by new rust resistant varieties was observed after the 2010/11 epidemic.
The most significant wheat grain yield increases were observed for farmers who increased both area under resistant varieties and number of wheat varieties grown per season.
The additional yield gain thanks to the large-scale adoption of yellow rust resistant varieties observed after the 2010/11 epidemic makes a very strong case to further strengthen wheat research and extension investments, so that more Ethiopian farmers have access to improved wheat varieties resistant to old and newly emerging rust races.
The International Maize and Wheat Improvement Center (CIMMYT’s) own Lucia Nevescanin Moreno is the first recipient of a new scholarship sponsored by the Heat and Drought Wheat Improvement Consortium (HeDWIC) for its doctoral training program.
The HeDWIC Doctoral Training Program evolved out of the MasAgro-Trigo project, thanks to funding from the Mexican Secretariat of Agriculture and Rural Development (SADER) and National Council for Science and Technology (Consejo Nacional de Ciencia y Tecnología, CONACYT). The idea of the initiative is to provide young scientists from climate or food security vulnerable regions with opportunities to conduct research at advanced institutes internationally, to boost heat and drought tolerance of wheat in their home country. The program is expected to expand to other climate vulnerable regions through similar efforts to train talented young scientists who wish to be involved in improving the climate resilience of crops.
Lucia, who is currently working as an assistant research associate with CIMMYT, will be pursuing a PhD on wheat root function under abiotic stress under the supervision of University of Nottingham professor of Plant Sciences Malcom Bennett starting in October.
We asked Lucia a few questions about her research and the importance of heat and drought resilience.
How did you hear
A professor from my master’s program told me about it. I was
doing a master’s in Natural Resources in the Instituto Tecnologico de Sonora,
working specifically on tropical dry forest in Northwest Mexico but I always
wanted to do science in a more applied way. I wanted to work on something that could
help other people. Food security is something that people need to pay a lot of
attention to. I started working for CIMMYT in February 2018 as an assistant research
associate in the Global Wheat Program, conducting experiments in different
conditions and I really learned a lot and am still learning a lot.
How did you hear
I was working with [CIMMYT Remote Sensing Specialist] Francisco
Pinto on wheat root research here at CIMMYT and he asked me if I wanted to
continue with my studies. I told him that I wanted to do a PhD and he showed me
this opportunity with HeDWIC and the University of Nottingham. So I applied and
I got it. Actually, I was very surprised to learn that I am the first PhD
recipient of the HeDWIC scholarship. It’s a lot of pressure!
What will you be
I will be studying wheat root function under abiotic stress
under the supervision of Malcom Bennett at the University of Nottingham. I will
be doing field-based phenotyping at Yaqui Valley in Mexico
to determine what root characteristics are underlying plant performance under a
range of environments including heat stress and water stress conditions. I
will be using techniques like x-ray and laser ablation tomography in controlled conditions at the University of Nottingham to
measure the physiology and anatomy of the wheat roots. I will also be working
with Francisco Pinto and Matthew Reynolds from CIMMYT, Darren Wells and Craig
Sturrock from the University of Nottingham and Jonathan Lynch from Penn State
Why do you think a
consortium like HeDWIC is important for food security?
With climate change occurring at such a rapid pace, we
really need to adapt to these new conditions. The population is also growing
and so the demand for food needs serious attention. In HeDWIC they are working
with external conditions like drought and heat and they are looking at how
crops can adapt to these conditions. I think that just looking at how to
increase yield is not enough, we need to look at how the crop will respond in
the different environmental conditions we will go through.
What advice would you
give to young women interested in a career in science?
I think it’s more difficult for women to adapt to this
environment of work but we just need to be brave and show that we can do it! I
was really interested in working in science because I wanted to know how things
work and why. Maybe with my research and with research in general we can help
people in power to make important decisions that can help other people. I think
that should be the principle purpose of science.
Lucia’s PhD is
supported by the CONACYT-Government of Mexico, SADER’s MasAgro Trigo and the University