CIMMYT’s experimental station in Obregón, a small city in Mexico’s state of Sonora, is considered a mecca for wheat research and breeding. In 1945, Norman Borlaug arrived as a geneticist for a special project between the Mexican government and the Rockefeller Foundation, to help local farmers with wheat production. After a few years, his strong bond with the community, students and interns was key to making a remarkable difference on wheat research that save millions from famine and won him the Nobel Peace Prize. A legacy that has lasted for many decades.
At Obregón, scientists have access to state-of-the-art field facilities and an ideal location, in the northern Yaqui Valley. The station’s dry climate and favorable temperature in winter is suitable to assess yield potential, while its hot summers are ideal to study wheat’s tolerance to different stressors.
Here, scientists and field workers work hard all year round to ensure the future of wheat. Varieties grown in all continents have CIMMYT and Sonoran DNA.
SPECIAL THANKS TO: Jeanie Borlaug Laube. Jesús Larraguibel Artola, President of PIEAES (Patronato para la Investigación y Experimentación Agrícola del Estado de Sonora A.C.). Asociación de Organismos de Agricultores del Sur de Sonora A.C. (AOASS) Global Wheat Program, CIMMYT: Alison Bentley (Program Director), Karim Ammar, Rodrigo Rascón, Carolina Rivera, Alberto Mendoza, Leonardo Crespo and Nele Verhulst.
CREDITS: Production: Alfonso Cortés, Marta Millere and Silvia Rico, CIMMYT. Additional drone shots: Courtesy of INIFAP and PIEAES. Post-production: Silvia Rico, CIMMYT
MUSIC: The Way Up created by Evert Z. Licensed from Artlist.io (License owner: CIMMYT. Creator Pro License Number – 159864). Eclipse created by EFGR. Licensed from Artlist.io (License owner: CIMMYT. Creator Pro License Number – 159864).
Representatives from the G20 Foreign Ministers’ meeting on July 7-8. (Credit: Antara Foto/Pool/Sigid Kurniawan/rwa.)
The G20 Foreign Ministers’ meeting held on July 7-8 in Bali saw Chinese State Councillor and Foreign Minister, Wang Yi, highlight support for CGIAR as part of a proposed cooperation initiative to boost global food security.
Foreign Minister Wang Yi highlighted the need to help CGIAR increase innovation and build cooperation on agricultural science and technology among countries. Addressing the meeting, Wang said the food and energy sectors are crucial for the healthy performance of the world economy and the effective implementation of the UN 2030 Agenda for Sustainable Development.
His statement was made shortly before the signing of Letters of Intent for Cooperation between the Chinese Academy of Agricultural Sciences (CAAS) and two CGIAR Research Centers, the International Maize and Wheat Improvement Center (CIMMYT) and the International Rice Research Institute (IRRI).
CIMMYT, IRRI and CAAS intend to establish a joint Center in Hainan to address global food security through advances in wheat and rice breeding. The collaboration aims to enhance the environmental sustainability of rice and wheat based agri-food systems, promote biodiversity conservation, combat climate change, and improve the health and welfare of growers and consumers.
Jean Balié, Regional Director, South East Asia and Pacific, CGIAR, and Director General of IRRI said: “Our new agreement solidifies and updates a longstanding and fruitful partnership. Today we face a different and growing set of challenges to our food, land and water systems, and we welcome the opportunity to strengthen knowledge and information exchange from across CGIAR that will contribute to a transformation of global food, land and water systems.”
CIMMYT Director General, Bram Govaerts added: “This state-of-the-art breeding center will help us develop and deploy the new nutritious, high-yielding and resilient varieties that Asian farmers need to feed and nurture the most populous region of the world sustainably or within planetary boundaries.”
In three decades of collaboration, CAAS and CGIAR have cooperated on germplasm exchange, breeding new varieties of crops, and providing opportunities for staff collaboration, development and training.
In wheat research, the partnership has added as much as 10.7 million tons of grain – worth $3.4 billion – to China’s national wheat output. Additionally,eight CIMMYTscientists have won the Chinese Friendship Award – the highest award for foreign experts who have made outstanding contributions to China’s economic and social progress.
A reaffirmation of Chinese support for CGIAR comes on a tide of growing recognition that more investment is needed to tackle hunger.
Earlier in the year the G7 Foreign Ministers’ Communiqué underlined the urgent need to address risk in global food systems citing this as a top foreign policy objective. At the same time, the G7 Agricultural Ministers Communiqué cautioned that slowing down work to address longer term goals of food systems transformation, in order to address short term food crises, will have negative consequences in the medium and long term. In this context CGIAR’s System Board Chair, Marco Ferroni, recently highlighted the need for world leaders to look at the big picture to solve the food crisis.
The Chinese Academy of Agricultural Sciences (CAAS), the International Maize and Wheat Improvement Center (CIMMYT) and the International Rice Research Institute (IRRI) are establishing a breeding center in Sanya, Hainan Province, China.
The international cooperation will be conducive to the exploration and utilization of germplasm resources of the research organizations, biological breeding research, technical training, and the innovation of the global seed industry.
This open-access textbook provides a comprehensive, up-to-date guide for students and practitioners wishing to access the key disciplines and principles of wheat breeding. Edited by Matthew Paul Reynolds, head of Wheat Physiology at CIMMYT, and Hans-Joachim Braun, former Director of CIMMYT’s Global Wheat Program, it covers all aspects of wheat improvement, from utilizing genetic resources to breeding and selection methods, data analysis, biotic and abiotic stress tolerance, yield potential, genomics, quality nutrition and processing, physiological pre-breeding, and seed production.
It will give readers a balanced perspective on proven breeding methods and emerging technologies. The content is rich in didactic material that considers the background to wheat improvement, current mainstream breeding approaches, translational research, and avant-garde technologies that enable breakthroughs in science to impact productivity, facilitating learning.
While the volume provides an overview for professionals interested in wheat, many of the ideas and methods presented are equally relevant to small grain cereals and crop improvement in general.
All chapter authors are world-class researchers and breeders whose expertise spans cutting-edge academic science to impacts in farmers’ fields.
Given the challenges currently faced by academia, industry, and national wheat programs to produce higher crop yields, often with fewer inputs and under increasingly harsher climates, this volume is a timely addition to their toolkit.
Spot blotch, a major biotic stress challenging bread wheat production is caused by the fungus Bipolaris sorokiniana. In a new study, scientists from the International Maize and Wheat Improvement Center (CIMMYT) evaluate genomic and index-based selection to select for spot blotch resistance quickly and accurately in wheat lines. The former approach facilitates selecting for spot blotch resistance, and the latter for spot blotch resistance, heading and plant height.
Genomic selection
The authors leveraged genotyping data and extensive spot blotch phenotyping data from Mexico and collaborating partners in Bangladesh and India to evaluate genomic selection, which is a promising genomic breeding strategy for spot blotch resistance. Using genomic selection for selecting lines that have not been phenotyped can reduce the breeding cycle time and cost, increase the selection intensity, and subsequently increase the rate of genetic gain.
Two scenarios were tested for predicting spot blotch: fixed effects model (less than 100 molecular markers associated with spot blotch) and genomic prediction (over 7,000 markers across the wheat genome). The clear winner was genomic prediction which was on average 177.6% more accurate than the fixed effects model, as spot blotch resistance in advanced CIMMYT wheat breeding lines is controlled by many genes of small effects.
“This finding applies to other spot blotch resistant loci too, as very few of them have shown big effects, and the advantage of genomic prediction over the fixed effects model is tremendous”, confirmed Xinyao He, Wheat Pathologist and Geneticist at CIMMYT.
The authors have also evaluated genomic prediction in different populations, including breeding lines and sister lines that share one or two parents.
Spot blotch susceptible wheat lines (left) and resistant lines. (Photo: Xinyao He and Pawan Singh/CIMMYT)
Index selection
One of the key problems faced by wheat breeders in selecting for spot blotch resistance is identifying lines that are genetically resistant to spot blotch versus those that escape and exhibit less disease by being late and tall. “The latter, unfortunately, is often the case in South Asia”, explained Pawan Singh, Head of Wheat Pathology at CIMMYT.
A potential solution to this problem is the use of selection indices that can make it easier for breeders to select individuals based on their ranking or predicted net genetic merit for multiple traits. Hence, this study reports the first successful evaluation of the linear phenotypic selection index and Eigen selection index method to simultaneously select for spot blotch resistance using the phenotype and genomic-estimated breeding values, heading and height.
This study demonstrates the prospects of integrating genomic selection and index-based selection with field based phenotypic selection for resistance in spot blotch in breeding programs.
A generalized wiring diagram for wheat, as proposed by the authors. The diagram depicts the traits most commonly associated with the source (left) and sink (right) strengths and others that impact both the sink and source, largely dependent on growth stage (middle). TGW, thousand grain weight.
As crop yields are pushed closer to biophysical limits, achieving yield gains becomes increasingly challenging. Traditionally, scientists have worked on the premise that crop yield is a function of photosynthesis (source), the investment of assimilates into reproductive organs (sinks) and the underlying processes that enable and connect the expression of both. Although the original source-and-sink model remains valid, it must embrace more complexity, as scientific understanding improves.
A group of international researchers are proposing a new wiring diagram to show the interrelationships of the physiological traits that impact wheat yield potential, published on Nature Food. By illustrating these linkages, it shows connections among traits that may not have been apparent, which could serve as a decision support tool for crop scientists. The wiring diagram can inform new research hypotheses and breeding decisions, as well as research investment areas.
The diagram can also serve as a platform onto which new empirical data are routinely mapped and new concepts added, thereby creating an ever-richer common point of reference for refining models in the future.
“If routinely updated, the wiring diagram could lead to a paradigm change in the way we approach breeding for yield and targeting translational research,” said Matthew Reynolds, Distinguished Scientist and Head of Wheat Physiology at the International Maize and Wheat Improvement Center (CIMMYT) and lead author of the study. “While focused on yield potential, the tool can be readily adapted to address climate resilience in a range of crops besides wheat.”
Breeding milestone
The new wiring diagram represents a milestone in deterministic plant breeding. It dovetails simpler models with crop simulation models.
This diagram can be used to illustrate the relative importance of specific connections among traits in their appropriate phenological context and to highlight major gaps in knowledge. This graphical representation can also serve as a roadmap to prioritize research at other levels of integration, such as metabolomic or gene expression studies. The wiring diagram can be deployed to identify ways for improving elite breeding material and to explore untapped genetic resources for unique traits and alleles.
Yield for climate resilience
The wheat scientific community is hard at work seeking new ways to get higher yields more quickly to help the world cope with population growth, climate change, wars and stable supplies of calories and protein.
“To ensure food and nutritional security in the future, raising yields must be an integral component of making crops more climate-resilient. This new tool can serve as a roadmap to design the necessary strategies to achieve these goals,” said Jeff Gwyn, Program Director of the International Wheat Yield Partnership (IWYP).
Matthew Reynolds – Distinguished Scientist and Head of Wheat Physiology at the International Maize and Wheat Improvement Center (CIMMYT)
Gustavo Ariel Slafer – Research Professor at the Catalonian Institution for Research and Advanced Studies (ICREA) and Associate Professor of the University of Lleida
For more information or to arrange interviews, please contact the CIMMYT media team:
The study is an international collaboration of scientists from the International Maize and Wheat Improvement Center (CIMMYT), the Catalonian Institution for Research and Advanced Studies (ICREA), the Center for Research in Agrotechnology (AGROTECNIO), the University of Lleida, the University of Nottingham, the John Innes Centre, Lancaster University, Technische Universität München, CSIRO Agriculture & Food, and the International Wheat Yield Partnership (IWYP).
ABOUT CIMMYT:
The International Maize and Wheat Improvement Center (CIMMYT) is an international organization focused on non-profit agricultural research and training that empowers farmers through science and innovation to nourish the world in the midst of a climate crisis.
Applying high-quality science and strong partnerships, CIMMYT works to achieve a world with healthier and more prosperous people, free from global food crises and with more resilient agri-food systems. CIMMYT’s research brings enhanced productivity and better profits to farmers, mitigates the effects of the climate crisis, and reduces the environmental impact of agriculture.
CIMMYT is a member of CGIAR, a global research partnership for a food-secure future dedicated to reducing poverty, enhancing food and nutrition security, and improving natural resources.
The International Wheat Yield Partnership (IWYP) represents a long-term global endeavor that utilizes a collaborative approach to bring together funding from public and private research organizations from a large number of countries. Over the first five years, the growing list of partners aims to invest up to US$100 million.
Wheat leaves showing symptoms of heat stress. (Photo: CIMMYT)
Across South Asia, including major wheat-producing regions of India and Pakistan, temperature extremes are threatening wheat production. Heatwaves have been reported throughout the region, with a century record for early onset of extreme heat. Monthly average temperatures across India for March and April 2022 exceeded those recorded over the past 100 years.
Widely recognized as one of the major breadbaskets of the world, the Indo-Gangetic Plains region produces over 100 million tons of wheat annually, from 30 million hectares in Bangladesh, India, Nepal and Pakistan, primarily supporting large domestic demand.
The optimal window for wheat planting is the first half of November. The late onset of the 2021 summer monsoon delayed rice planting and its subsequent harvest in the fall. This had a knock-on effect, delaying wheat planting by one to two weeks and increasing the risk of late season heat stress in March and April. Record-high temperatures over 40⁰C were observed on several days in March 2022 in the Punjabs of India and Pakistan as well as in the state of Haryana, causing wheat to mature about two weeks earlier than usual.
In-season changes and effects
Prior to the onset of extreme heat, the weather in the current season in India was favorable, prompting the Government of India to predict a record-high wheat harvest of 111 million tons. The March heat stress was unexpected and appears to have had a significant effect on the wheat crop, advancing the harvest and likely reducing yields.
Departure of the normalized difference vegetation index (NDVI) during the period from March 22 to April 7 from the average of the previous five years. The NDVI is a measure of the leaf area and the greenness of vegetation. The yellow areas in the Punjabs of India and Pakistan, as well as in the state of Haryana, indicate that wheat matured earlier than normal due to elevated temperatures. Maximum temperatures reached 40⁰C on March 15 and remained at or above this level throughout the wheat harvesting period. (Map: Urs Schulthess/CIMMYT).
In the North-Western Plains, the major wheat basket of India, the area of late-sown wheat is likely to have been most affected even though many varieties carry heat tolerance. Data from CIMMYT’s on-farm experiments show a yield loss between 15 to 20% in that region. The states of Haryana and Punjab together contribute almost 30% of India’s total wheat production and notably contribute over 60% of the government’s buffer stocks. In the North-Eastern Plains, in the states of Bihar and Uttar Pradesh, around 40% of the wheat crop was normal or even early sown, escaping heat damage, whilst the remainder of late-sown wheat is likely to be impacted at a variable level, as most of the crop in this zone matures during the third and fourth week of March.
The Government of India has now revised wheat production estimates, with a reduction of 5.7%, to 105 million tons because of the early onset of summer.
India has reported record yields for the past 5 years, helping it to meet its goal of creating a reserve stock of 40 million tons of wheat after the 2021 harvest. It went into this harvest season with a stock of 19 million tons, and the country is in a good position to face this year’s yield loss.
In Pakistan, using satellite-based crop monitoring systems, the national space agency Space & Upper Atmosphere Research Commission (SPARCO) estimated wheat production reduction close to 10%: 26 million tons, compared to the production target of 29 million tons, for the 2021-22 season.
We recommend that systematic research be urgently undertaken to characterize and understand the impacts of elevated temperatures on the health of field-based workers involved in wheat production. This is needed to develop a holistic strategy for adapting our global cropping systems to climate change.
India had pledged to provide increased wheat exports to bolster global supplies, but this now looks uncertain given the necessity to safeguard domestic supplies. During the COVID-19 pandemic, the Indian government supported domestic food security by providing free rations — mainly wheat and rice — to 800 million people over several months. This type of support relies on the availability of large buffer stocks which appear stable, but may be reduced if grain production and subsequent procurement levels are lower than desired.
We are already seeing indications of reduced procurement by governments with market prices running higher than usual. However, although the Food Corporation of India has procured 27% less wheat grain in the first 20 days of the wheat procurement season compared to the same period last year, the Government of India is confident about securing sufficient wheat buffer stocks.
As with the COVID-19 pandemic and the war in Ukraine, it is likely that the most marked effects of both climate change and shortages of staple crops will hit the poorest and most vulnerable communities hardest.
A chain reaction of climate impacts
The real impacts of reduced wheat production due to extreme temperatures in South Asia demonstrate the realities of the climate emergency facing wheat and agricultural production. Direct impacts on farming community health must also be considered, as our agricultural workforce is pushed to new physical limits.
Anomalies, which are likely to become the new normal, can set off a chain reaction as seen here: the late onset of the summer monsoon caused delays in the sowing of rice and the subsequent wheat crop. The delayed wheat crop was hit by the unprecedented heatwave in mid- to late March at a relatively earlier stage, thus causing even more damage.
Preparing for wheat production tipping points
Urgent action is required to develop applied mitigation and adaptation strategies, as well as to plan for transition and tipping points when key staple crops such as wheat can no longer be grown in traditional production regions.
A strategic design process is needed, supported by crop and climate models, to develop and test packages of applied solutions for near-future climate changes. On-farm evidence from many farmers’ fields in Northwestern India indicates that bundled solutions — no-till direct seeding with surface retention of crop residues coupled with early seeding of adapted varieties of wheat with juvenile heat tolerance — can help to buffer terminal heat stress and limit yield losses.
Last but not least, breeding wheat for high-temperature tolerance will continue to be crucial for securing production. Strategic planning needs to also encompass the associated social, market and political elements which underpin equitable food supply and stability.
Sorghum field in Kiboko, Kenya. (Photo: E Manyasa/ICRISAT)
As part of the One CGIAR reform, the Global Science Group on Genetic Innovation will implement a crop breeding and seed systems project for key crops including groundnut, sorghum and millet, across western and eastern African countries.
The International Maize and Wheat Improvement Center (CIMMYT), a leader in innovative partnerships, breeding and agronomic science for sustainable agri-food systems, will lead the project.
The Accelerated Varietal Improvement and Seed Delivery of Legumes and Cereals in Africa (AVISA) project aims to improve the health and livelihoods of millions by increasing the productivity, profitability, resilience and marketability of nutritious grain, legumes and cereal crops. The project focuses on strengthening networks to modernize crop breeding by CGIAR and national program partners, and public-private partnerships to strengthen seed systems. The project currently works in Burkina Faso, Ethiopia, Ghana, Mali, Nigeria, Uganda and Tanzania.
“Sorghum, groundnut and millets are essential staples of nutritious diets for millions of farmers and consumers and are crucial for climate-change-resilient farming systems,” explained CIMMYT Deputy Director General and Head of Genetic Resources, Kevin Pixley. “The oversight of this project by CGIAR’s Genetic Innovation Science Group will ensure continued support for the improvement of these crops in partnership with the national agricultural research and extension systems (NARES) that work with and for farmers,” he said.
“CIMMYT is delighted to lead this project on behalf of the Genetic Innovations Science Group and CGIAR,” confirms CIMMYT Director General, Bram Govaerts.
“We look forward to contributing to co-design and co-implement with partners and stakeholders the next generation of programs that leverage and build the strengths of NARES, CGIAR and others along with the research to farmers and consumers continuum to improve nutrition, livelihoods, and resilience to climate change through these crops and their cropping systems.”
Emerging in the last 120 years, science-based plant breeding begins by creating novel diversity from which useful new varieties can be identified or formed. The most common approach is making targeted crosses between parents with complementary, desirable traits. This is followed by selection among the resulting plants to obtain improved types that combine desired traits and performance. A less common approach is to expose plant tissues to chemicals or radiation that stimulate random mutations of the type that occur in nature, creating diversity and driving natural selection and evolution.
Determined by farmers and consumer markets, the target traits for plant breeding can include improved grain and fruit yield, resistance to major diseases and pests, better nutritional quality, ease of processing, and tolerance to environmental stresses such as drought, heat, acid soils, flooded fields and infertile soils. Most traits are genetically complex — that is, they are controlled by many genes and gene interactions — so breeders must intercross and select among hundreds of thousands of plants over generations to develop and choose the best.
Plant breeding over the last 100 years has fostered food and nutritional security for expanding populations, adapted crops to changing climates, and helped to alleviate poverty. Together with better farming practices, improved crop varieties can help to reduce environmental degradation and to mitigate climate change from agriculture.
Is plant breeding a modern technique?
Plant breeding began around 10,000 years ago, when humans undertook the domestication of ancestral food crop species. Over the ensuing millennia, farmers selected and re-sowed seed from the best grains, fruits or plants they harvested, genetically modifying the species for human use.
Modern, science-based plant breeding is a focused, systematic and swifter version of that process. It has been applied to all crops, among them maize, wheat, rice, potatoes, beans, cassava and horticulture crops, as well as to fruit trees, sugarcane, oil palm, cotton, farm animals and other species.
With modern breeding, specialists began collecting and preserving crop diversity, including farmer-selected heirloom varieties, improved varieties and the crops’ undomesticated relatives. Today hundreds of thousands of unique samples of diverse crop types, in the form of seeds and cuttings, are meticulously preserved as living catalogs in dozens of publicly-administered “banks.”
The International Maize and Wheat Improvement Center (CIMMYT) manages a germplasm bank containing more than 180,000 unique maize- and wheat-related seed samples, and the Svalbard Global Seed Vault on the Norwegian island of Spitsbergen preserves back-up copies of nearly a million collections from CIMMYT and other banks.
Through genetic analyses or growing seed samples, scientists comb such collections to find useful traits. Data and seed samples from publicly-funded initiatives of this type are shared among breeders and other researchers worldwide. The complete DNA sequences of several food crops, including rice, maize, and wheat, are now available and greatly assist scientists to identify novel, useful diversity.
Much crop breeding is international. From its own breeding programs, CIMMYT sends half a million seed packages each year to some 800 partners, including public research institutions and private companies in 100 countries, for breeding, genetic analyses and other research.
A field worker removes the male flower of a wheat spike, as part of controlled pollination in breeding. (Photo: Alfonso Cortés/CIMMYT)
A century of breeding innovations
Early in the 20th century, plant breeders began to apply the discoveries of Gregor Mendel, a 19th-century mathematician and biologist, regarding genetic variation and heredity. They also began to take advantage of heterosis, commonly known as hybrid vigor, whereby progeny of crosses between genetically different lines will turn out stronger or more productive than their parents.
Modern statistical methods to analyze experimental data have helped breeders to understand differences in the performance of breeding offspring; particularly, how to distinguish genetic variation, which is heritable, from environmental influences on how parental traits are expressed in successive generations of plants.
Since the 1990s, geneticists and breeders have used molecular (DNA-based) markers. These are specific regions of the plant’s genome that are linked to a gene influencing a desired trait. Markers can also be used to obtain a DNA “fingerprint” of a variety, to develop detailed genetic maps and to sequence crop plant genomes. Many applications of molecular markers are used in plant breeding to select progenies of breeding crosses featuring the greatest number of desired traits from their parents.
Plant breeders normally prefer to work with “elite” populations that have already undergone breeding and thus feature high concentrations of useful genes and fewer undesirable ones, but scientists also introduce non-elite diversity into breeding populations to boost their resilience and address threats such as new fungi or viruses that attack crops.
Transgenics are products of one genetic engineering technology, in which a gene from one species is inserted in another. A great advantage of the technology for crop breeding is that it introduces the desired gene alone, in contrast to conventional breeding crosses, where many undesired genes accompany the target gene and can reduce yield or other valuable traits. Transgenics have been used since the 1990s to implant traits such as pest resistance, herbicide tolerance, or improved nutritional value. Transgenic crop varieties are grown on more than 190 million hectares worldwide and have increased harvests, raised farmers’ income and reduced the use of pesticides. Complex regulatory requirements to manage their potential health or environmental risks, as well as consumer concerns about such risks and the fair sharing of benefits, make transgenic crop varieties difficult and expensive to deploy.
Genome editing or gene editing techniques allow precise modification of specific DNA sequences, making it possible to enhance, diminish or turn off the expression of genes and to convert them to more favorable versions. Gene editing is used primarily to produce non-transgenic plants like those that arise through natural mutations. The approach can be used to improve plant traits that are controlled by single or small numbers of genes, such as resistance to diseases and better grain quality or nutrition. Whether and how to regulate gene edited crops is still being defined in many countries.
The mobile seed shop of Victoria Seeds Company provides access to improved maize varieties for farmers in remote villages of Uganda. (Photo: Kipenz Films for CIMMYT)
Selected impacts of maize and wheat breeding
In the early 1990s, a CIMMYT methodology led to improved maize varieties that tolerate moderate drought conditions around flowering time in tropical, rainfed environments, besides featuring other valuable agronomic and resilience traits. By 2015, almost half the maize-producing area in 18 countries of sub-Saharan Africa — a region where the crop provides almost a third of human calories but where 65% of maize lands face at least occasional drought — was sown to varieties from this breeding research, in partnership with the International Institute of Tropical Agriculture (IITA). The estimated yearly benefits are as high as $1 billion.
Intensive breeding for resistance to Maize Lethal Necrosis (MLN), a viral disease that appeared in eastern Africa in 2011 and quickly spread to attack maize crops across the continent, allowed the release by 2017 of 18 MLN-resistant maize hybrids.
Improved wheat varieties developed using breeding lines from CIMMYT or the International Centre for Agricultural Research in the Dry Areas (ICARDA) cover more than 100 million hectares, nearly two-thirds of the area sown to improved wheat worldwide, with benefits in added grain that range from $2.8 to 3.8 billion each year.
Breeding for resistance to devastating crop diseases and pests has saved billions of dollars in crop losses and reduced the use of costly and potentially harmful pesticides. A 2004 study showed that investments since the early 1970s in breeding for resistance in wheat to the fungal disease leaf rust had provided benefits in added grain worth 5.36 billion 1990 US dollars. Global research to control wheat stem rust disease saves wheat farmers the equivalent of at least $1.12 billion each year.
Crosses of wheat with related crops (rye) or even wild grasses — the latter known as wide crosses — have greatly improved the hardiness and productivity of wheat. For example, an estimated one-fifth of the elite wheat breeding lines in CIMMYT international yield trials features genes from Aegilops tauschii, commonly known as “goat grass,” that boost their resilience and provide other valuable traits to protect yield.
Biofortification — breeding to develop nutritionally enriched crops — has resulted in more than 60 maize and wheat varieties whose grain offers improved protein quality or enhanced levels of micro-nutrients such as zinc and provitamin A. Biofortified maize and wheat varieties have benefited smallholder farm families and consumers in more than 20 countries across sub-Saharan Africa, Asia, and Latin America. Consumption of provitamin-A-enhanced maize or sweet potato has been shown to reduce chronic vitamin A deficiencies in children in eastern and southern Africa. In India, farmers have grown a high-yielding sorghum variety with enhanced grain levels of iron and zinc since 2018 and use of iron-biofortified pearl millet has improved nutrition among vulnerable communities.
Innovations in measuring plant responses include remote sensing systems, such as multispectral and thermal cameras flown over breeding fields. In this image of the CIMMYT experimental station in Obregón, Mexico, water-stressed plots are shown in green and red. (Photo: CIMMYT and the Instituto de Agricultura Sostenible)
Thefuture
Crop breeders have been laying the groundwork to pursue genomic selection. This approach takes advantage of low-cost, genome-wide molecular markers to analyze large populations and allow scientists to predict the value of particular breeding lines and crosses to speed gains, especially for improving genetically complex traits.
Speed breeding uses artificially-extended daylength, controlled temperatures, genomic selection, data science, artificial intelligence tools and advanced technology for recording plant information — also called phenotyping — to make breeding faster and more efficient. A CIMMYT speed breeding facility for wheat features a screenhouse with specialized lighting, controlled temperatures and other special fixings that will allow four crop cycles — or generations — to be grown per year, in place of only two cycles with normal field trials. Speed breeding facilities will accelerate the development of productive and robust varieties by crop research programs worldwide.
Data analysis and management. Growing and evaluating hundreds of thousands of plants in diverse trials across multiple sites each season generates enormous volumes of data that breeders must examine, integrate, and co-analyze to inform decisions, especially about which lines to cross and which populations to discard or move forward. New informatics tools such as the Enterprise Breeding System will help scientists to manage, analyze and apply big data from genomics, field and lab studies.
Following the leaders. Driven by competition and the quest for profits, private companies that market seed and other farm products are generally on the cutting edge of breeding innovations. The CGIAR’s Excellence in Breeding (EiB) initiative is helping crop breeding programs that serve farmers in low- and middle-income countries to adopt appropriate best practices from private companies, including molecular marker-based approaches, strategic mechanization, digitization and use of big data to drive decision making. Modern plant breeding begins by ensuring that the new varieties produced are in line with what farmers and consumers want and need.
Cover photo: CIMMYT experimental station in Toluca, Mexico. Located in a valley at 2,630 meters above sea level with a cool and humid climate, it is the ideal location for selecting wheat materials resistant to foliar diseases, such as wheat rust. Conventional plant breeding involves selection among hundreds of thousands of plants from crosses over many generations, and requires extensive and costly field, screenhouse and lab facilities. (Photo: Alfonso Cortés/CIMMYT)
Genomic selection identifies individual plants based on the information from molecular markers, DNA signposts for genes of interest, that are distributed densely throughout the wheat genome. For wheat blast, the results can help predict which wheat lines hold promise as providers of blast resistance for future crosses and those that can be advanced to the next generation after selection.
In this study, scientists from the International Maize and Wheat Improvement Center (CIMMYT) and partners evaluated genomic selection by combining genotypic data with extensive and precise field data on wheat blast responses for three sets of genetically diverse wheat lines and varieties, more than 700 in all, grown by partners at locations in Bangladesh and Bolivia over several crop cycles.
The study also compared the use of a small number of molecular markers linked to the 2NS translocation, a chromosome segment from the grass species Aegilops ventricosa that was introduced into wheat in the 1980s and is a strong and stable source of blast resistance, with predictions using thousands of genome-wide markers. The outcome confirms that, in environments where wheat blast resistance is determined by the 2NS translocation, genotyping using one-to-few markers tagging the translocation is enough to predict the blast response of wheat lines.
Finally, the authors found that selection based on a few wheat blast-associated molecular markers retained 89% of lines that were also selected using field performance data, and discarded 92% of those that were discarded based on field performance data. Thus, both marker-assisted selection and genomic selection offer viable alternatives to the slower and more expensive field screening of many thousands of wheat lines in hot-spot locations for the disease, particularly at early stages of breeding, and can speed the development of blast-resistant wheat varieties.
The research was conducted by scientists from the International Maize and Wheat Improvement Center (CIMMYT), the Bangladesh Wheat and Maize Research Institute (BWMRI), the Instituto Nacional de Innovación Agropecuaria y Forestal (INIAF) of Bolivia, the Borlaug Institute for South Asia (BISA) and the Indian Council of Agricultural Research (ICAR) in India, the Swedish University of Agricultural Sciences (Alnarp), and Kansas State University in the USA. Funding for the study was provided by the Bill & Melinda Gates Foundation, the Foreign and Commonwealth Development Office of the United Kingdom, the U.S. Agency for International Development (USAID), the CGIAR Research Program on Wheat (WHEAT), the Indian Council of Agricultural Research (ICAR), the Swedish Research Council, and the Australian Centre for International Agricultural Research (ACIAR).
Cover photo: A researcher from Bangladesh shows blast infected wheat spikes and explains how the disease directly attacks the grain. (Photo: Chris Knight/Cornell University)
At the same time, climate change has likely slowed breeding progress for high-yielding, broadly adapted wheat, according to the new study, published recently in Nature Plants.
“Breeders are usually optimistic, overlooking many climate change factors when selecting,” said Matthew Reynolds, wheat physiologist at the International Maize and Wheat Improvement Center (CIMMYT) and co-author of the publication. “Our findings undermine this optimism and show that the amplified interaction of wheat lines with the environment due to climate change has made it harder for breeders to identify outstanding, broadly adapted lines.”
What do 10 million data points tell scientists?
Each year for nearly half a century, wheat breeders taking part in the CIMMYT-led International Wheat Improvement Network (IWIN) have tested approximately 1,000 new, experimental wheat lines and varieties at some 700 field sites in over 90 countries.
Promising lines are taken up by wheat breeding programs worldwide, while data from the trials is used to guide global breeding and other critical wheat research, explained Wei Xiong, CIMMYT crop modeler/physiologist based in China and lead author of the new paper.
“To date, this global testing network has collected over 10 million data points, while delivering wheat germplasm estimated to be worth several billion dollars annually in extra productivity to hundreds of millions of farmers in less developed countries,” Xiong said.
Xiong and his colleagues analyzed “crossover interactions” — changes in the relative rankings of pairs of wheat lines — in 38 years of data from four kinds of wheat breeding trials, looking for the extent to which climate change or breeding progress have flipped those rankings. Two of the trials whose data they examined focused on yield in bread wheat and durum wheat, while the other two assessed wheat lines’ performance under high temperatures and in semi-arid environments, respectively.
In addition to raising yields, wheat breeders are endowing the crop with added resilience for rising temperatures.
“We found that warmer and more erratic climates since the 1980s have increased ranking changes in global wheat breeding by as much as 15 percent,” Xiong said. “This has made it harder for breeders to identify superior, broadly adapted lines and even led to scientists discarding potentially useful lines.”
Conversely, wheat cultivars emerging from breeding for tolerance to environmental stresses, particularly heat, are showing substantially more stable yields across a range of environments and fostering wheat’s adaptation to current, warmer climates, while opening opportunities for larger and faster genetic gains in the future, according to the study.
“Among other things, our findings argue for more targeted wheat breeding and testing to address rapidly shifting and unpredictable farming conditions,” Reynolds added.
For over a decade, the CGIAR Research Programs on Maize (MAIZE) and Wheat (WHEAT) have been at the forefront of research-for-development benefiting maize and wheat farmers in the Global South, especially those most vulnerable to the shocks of a changing climate.
From 2012 to 2021, MAIZE has focused on doubling maize productivity and increasing incomes and livelihood opportunities from sustainable maize-based farming systems. Through MAIZE, scientists released over 650 elite, high-yielding maize varieties stacked with climate adaptive, nutrition enhancing, and pest and disease resistant traits.
The WHEAT program has worked to improve sustainable production and incomes for wheat farmers, especially smallholders, through collaboration, cutting-edge science and field-level research. Jointly with partners, WHEAT scientists released 880 high-yielding, disease- and pest-resistant, climate-resilient and nutritious varieties in 59 countries over the life of the program.
To document and share this legacy, the MAIZE and WHEAT websites have been redesigned to highlight the accomplishments of the programs and to capture their impact across the five main CGIAR Impact Areas: nutrition, poverty, gender, climate and the environment.
We invite you to visit these visually rich, sites to view the global impact of MAIZE and WHEAT, and how this essential work will continue in the future.
CIMMYT’s relationship with Mexico is one of a kind: in addition to being the birthplace of the wheat innovations that led to the Green Revolution and the founding of CGIAR, Mexico is also where maize originated thousands of years ago, becoming an emblem of the country’s economy and identity.
Honoring this longstanding connection and celebrating Mexico’s key contribution to global wheat and maize production, Mexico City will host a photo exhibition from December 1, 2021, to January 15, 2022, in the Open Galleries Lateral, located on Paseo de la Reforma, one of city’s most iconic promenades.
Titled “Maize and Wheat Research in Focus: Celebrating a Decade of Research for Sustainable Agricultural Development Under the CGIAR Research Programs on Maize and Wheat,” the exhibition illustrates the impact of MAIZE and WHEAT over the last ten years. The selection of photographs documents the challenges faced by maize and wheat smallholders in different regions, and showcases innovative interventions made by national and regional stakeholders worldwide.
From pathbreaking breeding research on climate-smart varieties to helping farming families raise their incomes, the photos — taken by CGIAR photographers before the COVID-19 pandemic — capture both the breadth of the challenges facing our global agri-food systems and the spirit of innovation and cooperation to meet them head on.
Don’t miss the chance to visit the exhibition if you are in Mexico City!
The photo exhibition “Maize and Wheat Research in Focus: Celebrating a Decade of Research for Sustainable Agricultural Development Under the CGIAR Research Programs on Maize and Wheat” will be on display in Mexico City until January 15, 2022. (Photo: Alfonso Cortés/CIMMYT)
CIMMYT distinguished scientist Ravi Singh conducts research on a wheat field while. (Photo: BGRI)
World-renowned plant breeder Ravi Singh, whose elite wheat varieties reduced the risk of a global pandemic and now feed hundreds of millions of people around the world, has been announced as the 2021 Borlaug Global Rust Initiative (BGRI) Lifetime Achievement Award recipient.
Singh, distinguished scientist and head of Global Wheat Improvement at the International Maize and Wheat Improvement Center (CIMMYT), endowed hundreds of modern wheat varieties with durable resistance to fungal pathogens that cause leaf rust, stem rust, stripe rust and other diseases during his career. His scientific efforts protect wheat from new races of some of agriculture’s oldest and most devastating diseases, safeguard the livelihoods of smallholder farmers in the most vulnerable areas in the world, and enhance food security for the billions of people whose daily nutrition depends on wheat consumption.
“Ravi’s innovations as a scientific leader not only made the Cornell University-led Borlaug Global Rust Initiative possible, but his breeding innovations are chiefly responsible for the BGRI’s great success,” said Ronnie Coffman, vice chair of the BGRI and international professor of global development at Cornell’s College of Agriculture and Life Sciences. “Perhaps more than any other individual, Ravi has furthered Norman Borlaug’s and the BGRI’s goal that we maintain the global wheat scientific community and continue the crucial task of working together across international borders for wheat security.”
In the early 2000s, when a highly virulent rust race discovered in East Africa threatened most of the world’s wheat, Singh took a key leadership role in the formation of a global scientific coalition to combat the threat. Along with Borlaug, Coffman and other scientists, he served as a panel member on the pivotal report alerting the international community to the Ug99 outbreak and its potential impacts to global food security. That sounding of the alarm spurred the creation of the BGRI and the collaborative international effort to stop Ug99 before it could take hold on a global scale.
As a scientific objective leader for the BGRI’s Durable Rust Resistance in Wheat and Delivering Genetic Gain in Wheat projects, Singh led efforts to generate and share a series of elite wheat lines featuring durable resistance to all three rusts. The results since 2008 include resistance to the 12 races of the Ug99 lineage and new, high-temperature-tolerant races of stripe rust fungus that had been evolving and spreading worldwide since the beginning of the 21st century.
“Thanks to Ravi Singh’s vision and applied science, the dire global threat of Ug99 and other rusts has been averted, fulfilling Dr. Borlaug’s fervent wishes to sustain wheat productivity growth, and contributing to the economic and environmental benefits from reduced fungicide use,” Coffman said. “Ravi’s innovative research team at CIMMYT offered crucial global resources to stop the spread of Ug99 and the avert the human catastrophe that would have resulted.”
An innovative wheat breeder known for his inexhaustible knowledge and attention to genetic detail, Singh helped establish the practice of “pyramiding” multiple rust-resistance genes into a single variety to confer immunity. This practice of adding complex resistance in a way that makes it difficult for evolving pathogens to overcome new varieties of wheat now forms the backbone of rust resistance breeding at CIMMYT and other national programs.
Ravi Singh (center) with Norman Borlaug (left) and Hans Braun in the wheat fields at CIMMYT’s experimental station in Ciudad Obregón, in Mexico’s Sonora state. (Photo: CIMMYT)
The global champion for durable resistance
Ravi joined CIMMYT in 1983 and was tasked by his supervisor, mentor and friend, the late World Food Prize Winner Sanjaya Rajaram, to develop wheat lines with durable resistance, said Hans Braun, former director of CIMMYT’s Global Wheat Program.
“Ravi did this painstaking work — to combine recessive resistance genes — for two decades as a rust geneticist and, as leader of CIMMYT’s Global Spring Wheat Program, he transferred them at large scale into elite lines that are now grown worldwide,” Braun said. “Thanks to Ravi and his colleagues, there has been no major rust epidemic in the Global South for years, a cornerstone for global wheat security.”
Alison Bentley, Director of CIMMYT’s Global Wheat Program, said that “Building on Ravi’s exceptional work throughout his career, deployment of durable rust resistance in widely adapted wheat germplasm continues to be a foundation of CIMMYT’s wheat breeding strategy.”
Revered for his determination and work ethic throughout his career, Singh has contributed to the development of 649 wheat varieties released in 48 countries, working closely with scientists at national wheat programs in the Global South. Those varieties today are sown on approximately 30 million hectares annually in nearly all wheat growing countries of southern and West Asia, Africa and Latin America. Of these varieties, 224 were developed directly under his leadership and are grown on an estimated 10 million hectares each year.
In his career Singh has authored 328 refereed journal articles and reviews, 32 book chapters and extension publications, and more than 80 symposia presentations. He is regularly ranked in the top 1% of cited researchers. The CIMMYT team that Singh leads identified and designated 22 genes in wheat for resistance or tolerance to stem rust, leaf rust, stripe rust, powdery mildew, barley yellow dwarf virus, spot blotch, and wheat blast, as well as characterizing various other important wheat genome locations contributing to durable resistance in wheat.
Singh’s impact as a plant breeder and steward of genetic resources over the past four decades has been extraordinary, according to Braun: “Ravi Singh can definitely be called the global champion for durable resistance.”
A CIMMYT researcher and a field worker lay out wheat seed for planting at the center’s headquarters in Texcoco, Mexico. In experimental trials, hundreds or thousands of wheat lines are planted for evaluation, each in small quantities, and so they are carefully laid out and sown by hand. (Photo: CIMMYT)
To help feed a growing world population, wheat scientists have turned to innovative technologies like genomic selection to hasten selection for positive traits — such as high grain yield performance and good grain quality — in varieties that are still undergoing testing. Instead of being shackled by the long duration of traditional breeding cycles, genomic selection allows scientists to make predictions regarding which traits will present when crossing two varieties; allowing breeders greater guidance and lessening potential time lost when crossing varieties that do not display potential for genetic gain. To reap the benefits of genomic selection, it is vital that the predictive models employed are as accurate as possible.
Currently, wheat breeders select characteristics like grain yield performance early in the breeding process, while selecting traits like good grain quality at a later stage in the breeding process.
In an article in the journal G3 Genes, researchers from the International Maize and Wheat Improvement Center (CIMMYT), and partners, led by CIMMYT scientist José Crossa along with Leonardo A. Crespo, Maria Itria Ibba and Alison R. Bentley, endeavored to determine if genomic prediction models could select for both characteristics simultaneously in the breeding process. This would improve selection accuracy in both early and later breeding stages, resulting a reduction in time and expense in delivering improved wheat varieties. They also tested the accuracy of a set of specific mathematical corrections applied to genomic predictions. These correction models identify correlations between genomic predictions and observed breeding values, such as increased yield or grain quality.
Considering two or more traits, like grain yield and good grain quality, is an example of a multi-trait model. The team examined this multi-trait model against a single trait model that improves one specific trait. Overall, the researchers found that prediction performance was highest using the multi-trait model.
However, the team also demonstrated that when breeding programs arrive at their genetic predictions, applying a specific correction method will account for differences between the predicted breeding value and the actual observed breeding value. Current correction models tend to underestimate that difference, which results in breeding programs not running as efficiently as possible.
By partnering selections from different stages in the breeding process and examining the resulting genetic predictions through a more appropriate correction model, the team has shown that breeding programs can use this to their benefit in developing and ultimately releasing improved wheat varieties that meet growing yield needs worldwide and respond to abiotic and biotic stressors.
Gyanendra Pratap Singh (center), Director of ICAR-IIWBR, presents at the 60th All India Wheat and Barley Research Workers’ Meet. (Photo: Courtesy of ICAR-IIWBR)
The International Maize and Wheat Improvement Center’s (CIMMYT) legacy of work with the Indian Centre for Agricultural Research (ICAR) has once again produced more successful collaborations this year. This solid partnership resulted in the release of new varieties poised to bring new, superior yielding, disease-resistant, high-quality wheat varieties suitable for different production environments to Indian farms.
The National Variety Release Committee announced the release of nine new varieties at the 60th All India Wheat and Barley Research Workers’ Virtual Meet on August 23–24, 2021, hosted by the Indian Institute of Wheat and Barley Research (IIWBR) of ICAR. Of the nine new varieties identified, five were selected by national partners from CIMMYT international trials and nurseries.
At the event, ICAR-IIWBR director Gyanendra Pratap (GP) Singh highlighted the impressive growth trajectory of India’s wheat production, estimated at 109.52 million tons of wheat harvested in 2021, a figure which was 86.53 million tons in 2015 and less than 60 million tons in 1991. Singh highlighted that this success is dependent upon the deployment of superior wheat varieties, bridging yield and information gaps, strengthened seed value chain, supportive government policies and, of course, farmer support to adopt new varieties and technologies.
The CIMMYT-derived varieties announced at the meeting include DBW296, DBW327, DBW332, HUW296 and JKW261. A few days earlier, variety PBW869 was released by the Punjab Agricultural University for growing in Punjab State under conservation agriculture practices.
“An innovative and powerful feature of ICAR-CIMMYT collaboration has been the introduction of long-term (10-month) rotational involvement of Indian young scientists in CIMMYTs breeding program at Mexico as well as in wheat blast screening in Bolivia,” said Arun Joshi, CIMMYT Regional Representative for Asia and Managing Director, Borlaug Institute for South Asia (BISA). “In this way, the breeding program of CIMMYT is an excellent example of joint breeding program with national institutions.”
At the 60th All India Wheat and Barley Research Workers’ Meet, participants highlighted new varieties, production growth and strengthened collaboration. (Photo: CIMMYT)
Beyond expectations
In addition to these important new wheat varieties, some CIMMYT-derived wheat varieties that were released in recent years have now been deemed suitable for regions beyond their initial region of cultivation, showing wide adaptation and yield stability.
Wheat variety DBW222, released in 2020 for the northwestern plain zone, has now been deemed suitable for cultivation in the northeastern plain zone. Similarly, DBW187, which was initially released for the northeastern plain zone, and then for northwestern plain zone as well for early sowing, is now also extended for sowing in the central zone, together representing 25 million hectares of the 31 million hectares of wheat grown in India.
“Farmers prefer these types of varieties that give them flexibility during sowing time, and have high, stable yields, and disease resistance,” GP Singh said at the meeting.
A major achievement discussed at this year’s event was that three of the new varieties — DBW187, DBW303 and DBW222 — achieved record-high demand in Breeders Seed Indent, with first, second and seventh ranks, respectively. This is a reflection and indirect measure of popularity and demand for a variety. IIWBR’s innovative strategy to implement pre-release seed multiplication and create demand for seeds from new varieties has led to a faster turnover of improved varieties.
According to Ravi Singh, Distinguished Scientist and Head of Global Wheat Improvement at CIMMYT, the collaborators are “further expanding our partnership through the support from the Accelerating Genetic Gains in Maize and Wheat (AGG) and zinc-mainstreaming projects, to expand testing of larger sets of elite lines in targeted populations of environments of the four South Asian countries where various IIBWR-affiliated institutions shall expand testing in the 2021–22 crop season.” CIMMYT looks forward to continuing ongoing and new collaborations with the ICAR-IIWBR programs to deliver even faster genetic gain for yield and grain zinc levels in new varieties, he explained.
Speaking during the meeting Alison Bentley, Director of CIMMYT’s Global Wheat Program, highlighted the collaborative efforts underway as part of the AGG project to accelerate breeding progress. “Innovations and discoveries in breeding approaches are being rapidly made — with further investment needed — to quickly and equitably accumulate and deploy them to farmers,” she said.
