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Theme: Environmental health and biodiversity

The world needs better management of water, soil, nutrients, and biodiversity in crop, livestock, and fisheries systems, coupled with higher-order landscape considerations as well as circular economy and agroecological approaches.

CIMMYT and CGIAR use modern digital tools to bring together state-of-the-art Earth system observation and big data analysis to inform co-design of global solutions and national policies.

Our maize and wheat genebanks preserve the legacy of biodiversity, while breeders and researchers look at ways to reduce the environmental footprint of agriculture.

Ultimately, our work helps stay within planetary boundaries and limit water use, nutrient use, pollution, undesirable land use change, and biodiversity loss.

Brown and green fields. (Photo: Elizabeth Lies/Unsplash)

Q&A: Regenerative agriculture for soil health

Written by Madeline Dahm on . Posted in Features.

South Asia was the epicenter of the Green Revolution, a historic era of agricultural innovation that fed billions of people on the brink of famine.

Yet despite the indisputably positive nutritional and developmental impacts of the Green Revolution of the 1960s, the era of innovation also led to the widespread use of farming practices—like intensive tilling, monoculture, removal and burning of crop residues, and over-use of synthetic fertilizer—that have a deleterious effect on the soil and cause off-site ecological harm. Excess pumping of irrigation water over decades has dried out the region’s chief aquifer.

South Asia’s woes illustrate the environmental costs of intensive food production to feed our densely-populated planet. Currently, one billion hectares of land worldwide suffers from degraded soils.

The International Maize and Wheat Improvement Center (CIMMYT) works with two of the world’s most widely cultivated and consumed cereal crops. To grow enough of these staple foods to feed the world, a second Green Revolution is needed: one that avoids the mistakes of the past, regenerates degraded land and reboots biodiversity in farm areas.

M.L. Jat, a CIMMYT Principal Scientist, has spent 20 years studying and promoting sustainable agricultural practices for maize- and wheat-based farming systems. In the following Q&A, Jat tells us about regenerative agriculture: integrated farming and grazing practices intended to rebuild soil organic matter and restore degraded soil biodiversity.

Q: What major components or practices are part of regenerative agriculture?

A: Regenerative agriculture is a comprehensive system of farming that harnesses the power of soil biology to rebuild soil organic matter, diversify crop systems, and improve water retention and nutrient uptake. The depletion of biodiversity, degradation of soil health, warming, and drier weather in farm areas have necessitated a reversal in agriculture from “degeneration to regeneration.”

The practices address food and nutritional security challenges while protecting natural resources and lowering agriculture’s environmental footprint, in line with the United Nations Sustainable Development Goals. CIMMYT has worked for years to research and promote conservation agriculture, which contributes to the aims of regenerative agriculture, and is already practiced on more than 200 million hectares globally — 15% of all cropland — and is expanding at a rate of 10.5 million hectares per year.

Q: What are the potential roles of major food crops — maize, rice, and wheat — in regenerative agriculture systems?

A: Regenerative agriculture is “crop neutral;” that is, it is applicable to almost all crops and farming systems. The world’s rice, wheat, and maize crops have an enormous physical and ecological footprint on land and natural resources, but play a critical role in food and nutrition security. Considering that anthropogenic climate change has reduced the global agricultural total factor productivity by about 21% in the past six decades, applying regenerative agriculture approaches to these systems represents a momentous contribution toward sustainable farming under increasing climatic risks.

Download "Regenerative Agriculture for Soil Health, Food and Environmental Security: Proceedings and Recommendations” from the Trust for Advancement of Agricultural Sciences.
Download “Regenerative Agriculture for Soil Health, Food and Environmental Security: Proceedings and Recommendations”.

Q: What elements or approaches of regenerative agriculture are applicable in India and how can they be applied?

A: Regenerative practices for maize and wheat systems in India include no-tillage, crop residue recycling, legume inter-cropping and cover crops, crop diversification, integrated nutrient management, and precision water management.

The potential area of adoption for regenerative agriculture in India covers at least 50 million hectares across a diversity of cropping systems and agroecologies — including irrigated, rainfed, and arid farmlands — and can be approached through appropriate targeting, investments, knowledge and capacity enhancement, and enabling policies.

In the breadbasket region of the Indo-Gangetic Plains, regenerative agriculture can help address the aforementioned second-generation problems of the Green Revolution, as well as contributing to the Indian government’s Soil Health Mission and its COP26 commitments.

Q: In order to get regenerative agriculture off the ground in South Asia, who will be involved?

A: Adapting and applying regenerative agriculture’s portfolio of practices will require the participation of all stakeholders associated with farming. Application of these principles is location- and situation-specific, so researchers, extension functionaries, value chain actors, philanthropists, environmentalists, NGOs, farmers, and policy planners all have a role to play in the impact pathway.

CIMMYT, the Borlaug Institute for South Asia (BISA), public and private programs and agencies, and farmers themselves have been developing, refining, and scaling out conservation agriculture-based regenerative agriculture practices for some three decades in South Asia. CIMMYT and BISA will continue to play a key role in mainstreaming regenerative agriculture in local, national, and regional development plans through science-based policy and capacity development.

Q: Farmers constitute a strong economic and political force in India. How can they be brought on board to practice regenerative agriculture, which could be more costly and knowledge-intensive than their current practices?

A: We need to pursue business “unusual” and harness the potential opportunities of regenerative agriculture to sequester soil carbon and reduce greenhouse gas emissions. Regenerative agriculture practices can offer farmers additional income and certainly create a “pull factor” for their adoption, something that has already started and will constitute a strong business case. For example, innovative business models give farmers an opportunity to trade ecosystem services and carbon credits through repurposing subsidies and developing carbon markets for private sectors. CIMMYT, along with the Indian Council of Agricultural Research and private partners such as Grow Indigo, are already helping to put in place a framework to acquire carbon credits through regenerative agriculture in India.

For more information about the application of regenerative agriculture on India’s farmlands, see “Regenerative Agriculture for Soil Health, Food and Environmental Security: Proceedings and Recommendations” from the Trust for Advancement of Agricultural Sciences.

Cover photo: Brown and green fields. (Photo: Elizabeth Lies/Unsplash)

MAIZE partners announce a new manual for effectively managing maize lethal necrosis (MLN) disease

Written by Sarah McLaughlin on . Posted in Features.

For a decade, scientists at the International Maize and Wheat Improvement Center (CIMMYT) have been at the forefront of a multidisciplinary and multi-institutional effort to contain and effectively manage maize lethal necrosis (MLN) disease in Africa.

When the disease was first reported in Kenya 2011 it spread panic among stakeholders. Scientists soon realized that almost all commercial maize varieties in Africa were susceptible. What followed was a superlative effort coordinated by the CGIAR Research Program on Maize (MAIZE) to mobilize “stakeholders, resources and knowledge” that was recently highlighted in an external review of program.

The publication of Maize Lethal Necrosis (MLN): A Technical Manual for Disease Management builds on the partnerships and expertise accrued over the course of this effort to provide a comprehensive “guide on best practices and protocols for sustainable management of the MLN.”

The manual is relevant to stakeholders in countries where MLN is already present, and also aims to offer technical tips to “‘high-risk’ countries globally for proactive implementation of practices that can possibly prevent the incursion and spread of the disease,” writes B.M. Prasanna, director of CIMMYT’s Global Maize Program and MAIZE, in the foreword.

“While intensive multi-disciplinary and multi-institutional efforts over the past decade have helped in containing the spread and impact of MLN in sub-Saharan Africa, we cannot afford to be complacent. We need to continue our efforts to safeguard crops like maize from devastating diseases and insect-pests, and to protect the food security and livelihoods of millions of smallholders,” says Prasanna, who is presently leading the OneCGIAR Plant Health Initiative Design Team.

CIMMYT scientist receives award for weed research

Written by Nima Chodon on . Posted in News.

Ram Kanwar Malik (center) with his team in Bihar, India, during a field visit.
Ram Kanwar Malik (center) with his team in Bihar, India, during a field visit.

Today the Weed Science Society of America (WSSA) announced the Honorary Member award for Ram Kanwar Malik, senior scientist at the International Maize and Wheat Improvement Center (CIMMYT). This award is given every year to a person who has made outstanding contributions to weed science “through their research, teaching, publishing and outreach.”

Malik’s early engagement in agricultural sustainability led to initiatives exploring herbicide resistance evolution and management, zero tillage, and other resource-conservation technologies. At the Cereal Systems Initiative for South Asia (CSISA) — a regional project led by CIMMYT — Malik and his colleagues helped promote the practice of early wheat sowing to beat terminal heat stress, resulting in increased wheat yield in India’s eastern Indo-Gangetic Plains.

“WSSA’s Honorary Member award is one of the highest recognitions bestowed by the Weed Science Society of America,” said Krishna Reddy, Chair of the WSSA 2022 Award Committee. “[The] Honorary Member is selected for meritorious service to weed science, among non-members from North America or any weed scientist from other countries. Only one person per year is awarded this membership. Dr. Malik’s significant research in weed science and his collaborative effort to deliver solutions for farmers in developing countries like India is inspirational.”

The award was presented virtually at the 2022 annual meeting of WSSA, held in Vancouver, Canada.

Transforming rice–wheat systems

<em>Phalaris minor</em> is a pernicious weed that affects crops like wheat and substantially reduces its yield potential.
Phalaris minor is a pernicious weed that affects crops like wheat and substantially reduces its yield potential.

Malik has worked extensively in the Indo-Gangetic Plains, leading many initiatives and innovations over the years, in collaboration with national and international partners. The WSSA award highlights Malik’s inspiring work in tackling herbicide resistance problems, first reported in India by his team in 1993. Malik was instrumental in developing a management solution for herbicide-resistant Phalaris minor, a pernicious weed in wheat crops. The integrated weed management system he helped develop raised wheat yield capacity significantly for farmers in the Indo-Gangetic Plains.

“The WSSA Honorary Member award reiterates the importance of agronomic management for sustained weed control strategies across cropping systems,” Malik said. “CIMMYT and partners, including the Australian Centre for International Agricultural Research (ACIAR), were the first to introduce zero tillage in wheat as part of a strategy to manage weed resistance problems in India. It is an honor that WSSA has recognized this collective work of ours,” he acknowledged.

Malik has devoted more than thirty years to transforming agricultural systems in the Indo-Gangetic Plains, working closely with farmers and partners, and building the capacity of national agricultural and research extension systems. he is a firm believer in farmers’ participation: “Large-scale adoption of sustainable agricultural practices is possible when we work together to leverage technologies which are mutually agreed by partners and meet farmers’ needs.”

Malik is a fellow of the Indian Society of Agronomy and the Indian Society of Weed Science (ISWS), which granted him the Lifetime Achievement Award. He has also received the Outstanding Achievement Award from the International Weed Science Society (IWSS) and the 2015 Derek Tribe Award from the Crawford Fund.

He remains passionate about and invested in changing the lives of farmers through better-bet agronomy and by leading innovative research at CIMMYT.

About the Weed Science Society of America (WSSA)

Founded in 1956, WSSA is a nonprofit scientific society that encourages and promotes the development of knowledge concerning weeds and their impact on the environment.

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)

Plant breeding innovations

Written by Mike Listman on . Posted in Explainers.

What is plant breeding?

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 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)
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 ObregĂłn, Mexico, water-stressed plots are shown in green and red. (Photo: CIMMYT and the Instituto de Agricultura Sostenible)
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 ObregĂłn, Mexico, water-stressed plots are shown in green and red. (Photo: CIMMYT and the Instituto de Agricultura Sostenible)

The future

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)

A researcher from Bangladesh shows blast infected wheat spikes and explains how the disease directly attacks the grain. (Photo: Chris Knight/Cornell University)

New publications: Genome-wide breeding to curtail wheat blast

Written by Mike Listman on . Posted in Publications.

A recent publication in the journal Frontiers of Plant Science provides results of the first-ever study to test genomic selection in breeding for resistance to wheat blast, a deadly disease caused by the fungus Magnaporthe oryzae that is spreading from its origin in Brazil to threaten wheat crops in South Asia and sub-Saharan Africa.

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.

Read the full study:
Genomic Selection for Wheat Blast in a Diversity Panel, Breeding Panel and Full-Sibs Panel

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 InnovaciĂłn 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)

How interactions among hidden enemies and drought effects grain yield and disease severity in bread wheat

Written by Sarah McLaughlin on . Posted in Features.

In nature, plants are simultaneously exposed to a complex system of biotic and abiotic stresses that limit crop yield. The cereal cyst nematode Heterodera filipjevi and dryland crown rot, caused by Fusarium, are important diseases facing cereal production around the world that cause significant yield loss. Yield loss accelerates when those diseases coexist with other abiotic stresses, such as drought.

Hexaploid bread wheat (Triticum aestivum L.) is an essential staple food for a large part of the world’s population, covering around 20% of daily caloric intake in the human diet, with global production at about 670.8 million tons per year, produced over 215.4 million hectares of land worldwide. Therefore, the program studying soil-borne pathogens at the International Maize and Wheat Improvement Center (CIMMYT)’s Turkey office initiated a study to investigate the effect of soil borne diseases (H. filipjevi and Fusarium culmorum) individually and in combination with drought on some morphological and physiological traits in wheat germplasm with different genetic tolerances to the three studied factors.

In this study, yield components included thousand kernel weight, spike weight, seed per spike and total grain yield. Morphological parameters, including plant height, final plant number (seedling emergence), relative water content, leaf chlorophyll content, H. filipjevi cyst number and presence of crown rot, were studied under greenhouse conditions in Turkey.

The main findings of the study showed that the interaction among water stress, F. culmorum and H. filipjevi increased the damage on the wheat parameters studied when compared with each stress applied alone. One of the most significant damages was seen in high seedling mortality under the three combined stresses (56% seedling death rate), which indicates the damage on wheat yield might occur at the seedling stage rather than later stages. This reduces plant density per area, which was ultimately responsible for low grain yield produced. The known dryland disease, crown rot, caused by F. culmorum, was significantly pronounced under water-stressed conditions.

In all studied parameters, the lowest damage was found among the resistant cultivars to biotic or abiotic stresses. This underscores the importance of wheat breeding programs to develop resistant germplasm, and reminds farmers to replace their old, susceptible varieties with new, resistant ones.

Based on our intensive experience in the CWANA region, most wheat growers basically do not recognize soil borne pathogens as a problem. In fact, most of them do not know that what nematode or soil fungal species are in their fields affecting yield. The term “hidden enemy” perfectly applies to the problems in the region and beyond. Integrated pest management (IPM) is, however, not practiced in the entire region and soil borne pathogen-induced yield losses are simply accepted.

We can conclude from this study that yield reduction in wheat due to soil borne pathogens could be lessened by improving and understanding the concept of IPM in the region where the practice of winter mono-culturing of wheat is the norm. Management of cereal soil-borne pathogens, especially cereal cyst nematode and crown rot, could involve an integrated approach that includes crop rotation, genetic resistance, crop nutrition and appropriate water supply.

Cover photo: Four different test crops show different stresses: T1V8 = Drought, T2V8 = Drought and Nematodes, T3V8 = Drought and fungus, T4V8 = Drought and nematode and fungus together. (Credit: CIMMYT)

Irrigated wheat field. (Photo: S. Sukumaran/CIMMYT)

CIMMYT trains next generation of scientists to tackle soil-borne pathogens

Written by Alison Doody on . Posted in News.

Two new students have graduated from the International Maize and Wheat Improvement Center’s (CIMMYT’s) Soil-Borne Pathogens program. The two new graduates, Khawla Mehalaine and Salah-Eddine Laasli, were supervised by CIMMYT senior scientist Abdelfattah Dababat.

He leads the Soil-Borne Pathogens program, which focuses on identifying the main soil-borne pathogens associated with cereals and developing an integrated pest management approach to combat them. The research team is particularly interested in finding novel sources of resistance against these pathogens.

Over the last two decades, CIMMYT scientists leading the Soil-Borne Pathogens program have trained tens of students which constitute the next generation of top researchers on this topic. Through this program, CIMMYT has also organized workshops and courses in North Africa, including a symposium on cereal nematodes held in Agadir, Morocco, in 2017.

Since soil-borne pathogens are exacerbated by water stress conditions, researchers have identified the Central and West Asia and North Africa regions as priority areas, due to their vulnerability to drought.

On March 1, 2021, Syngenta, in collaboration with CIMMYT and other partners, led the first One Earth Soil and Root Health Forum, an event which examined the importance of root and soil health to food security, climate resilience and livelihoods. The event also created a community for action on root and soil health.

Khawla Mehalaine celebrates graduating from her PhD. (Photo: handout)
Khawla Mehalaine celebrates graduating from her PhD. (Photo: handout)

Nematodes in Algeria

Mehalaine holds an engineering degree in agronomy and a master’s degree in plant protection from the Higher National School of Agronomy (ENSA) in Algeria. She successfully defended her PhD dissertation “Studies of cereal cyst nematodes of the genus Heterodera in the regions of northern Algeria” in June 2021, graduating from ENSA with honors.

She studied the behavior of four durum wheat varieties against cereal cyst nematodes through field surveys, molecular identification at species levels, and by evaluating the yield components of these wheat varieties.

She was promoted by ENSA professor Hammach M. and supervised by Dababat from CIMMYT, and professors Mustafa Imren and Göksel Özer from Abant Izzet Baysal University in Turkey.

“Completing my doctorate was a truly enriching experience and a challenging but rewarding journey,” Mehalaine said. “It was a collective effort and I am extremely grateful to Dr Abdelfattah Dababat for sharing his scientific skills, for his patience and support, and for all the opportunities I was given to further my research. Thanks to him, I got to know the world of nematodes. Special thanks to CIMMYT for funding the molecular study part.”

Salah-Eddine Laasli on his graduation day. (Photo: handout)
Salah-Eddine Laasli on his graduation day. (Photo: handout)

Root-lesion nematode and crown rot fungi

Laasli graduated with an International Master of Agronomic and Environmental Nematology (IMANEMA) from Ghent University, in collaboration with CIMMYT, the National Institute of Agricultural Research in Morocco and the Faculty of Agriculture at Abant Izzet Baysal University in Turkey.

His master thesis, entitled “Interaction of Root-Lesion Nematode (Pratylenchus thornei) and Crown Rot fungi (Fusarium culmorum) associated with wheat resistance under simulated field conditions,” was promoted by Wim Bert, a professor at the University of Ghent, and Dababat. The project was also supervised by Imren and Özer.

Laasli evaluated the host status of 150 spring wheat lines to both P. thornei and F. culmorum, and estimated the damage caused by the disease complex involving both pathogens at different infection scenarios. He found several lines that possessed multiple resistance to both diseases tested — which could be powerful sources of resistance for breeding program worldwide.

Cover photo: Irrigated wheat field. (Photo: S. Sukumaran/CIMMYT)

Bringing wild wheat’s untapped diversity into elite lines

Written by Rodrigo Ordóñez on . Posted in Features.

A collaboration involving 15 international institutes across eight countries has optimized efforts to introduce beneficial traits from wild wheat accessions in genebanks into existing wheat varieties.

The findings, published in Nature Food, extend many potential benefits to national breeding programs, including improved wheat varieties better equipped to thrive in changing environmental conditions. This research was led by Sukhwinder Singh of the International Maize and Wheat Improvement Center (CIMMYT) as part of the Seeds of Discovery project.

Since the advent of modern crop improvement practices, there has been a bottleneck of genetic diversity, because many national wheat breeding programs use the same varieties in their crossing program as their “elite” source. This practice decreases genetic diversity, putting more areas of wheat at risk to pathogens and environmental stressors, now being exacerbated by a changing climate. As the global population grows, shocks to the world’s wheat supply result in more widespread dire consequences.

The research team hypothesized that many wheat accessions in genebanks — groups of related plant material from a single species collected at one time from a specific location — feature useful traits for national breeding programs to employ in their efforts to diversify their breeding programs.

“Genebanks hold many diverse accessions of wheat landraces and wild species with beneficial traits, but until recently the entire scope of diversity has never been explored and thousands of accessions have been sitting on the shelves. Our research targets beneficial traits in these varieties through genome mapping and then we can deliver them to breeding programs around the world,” Singh said.

Currently adopted approaches to introduce external beneficial genes into breeding programs’ elite cultivars take a substantial amount of time and money. “Breeding wheat from a national perspective is a race against pathogens and other abiotic threats,” said Deepmala Sehgal, co-author and wheat geneticist in the Global Wheat program at CIMMYT. “Any decrease in the time to test and release a variety has a huge positive impact on breeding programs.”

Deepmala Sehgal shows LTP lines currently being used in CIMMYT trait pipelines at the experimental station in Toluca, Mexico, for introgression of novel exotic-specific alleles into newly developed lines. (Photo: CIMMYT)
Deepmala Sehgal shows LTP lines currently being used in CIMMYT trait pipelines at the experimental station in Toluca, Mexico, for introgression of novel exotic-specific alleles into newly developed lines. (Photo: CIMMYT)

Taking into genetic biodiversity

The findings build from research undertaken through the Seeds of Discovery project, which genetically characterized nearly 80,000 samples of wheat from the seed banks of CIMMYT and the International Center for Agricultural Research in the Dry Areas (ICARDA).

First, the team undertook a large meta-survey of genetic resources from wild wheat varieties held in genebanks to create a catalog of improved traits.

“Our genetic mapping,” Singh said, “identifies beneficial traits so breeding programs don’t have to go looking through the proverbial needle in the haystack. Because of the collaborative effort of the research team, we could examine a far greater number of genomes than a single breeding program could.”

Next, the team developed a strategic three-way crossing method among 366 genebank accessions and the best historical elite varieties to reduce the time between the original introduction and deployment of an improved variety.

Sukhwinder Singh (second from left) selects best performing pre-breeding lines in India. (Photo: CIMMYT)
Sukhwinder Singh (second from left) selects best performing pre-breeding lines in India. (Photo: CIMMYT)

Worldwide impact

National breeding programs can use the diverse array of germplasm for making new crosses or can evaluate the germplasm in yield trials in their own environments.

The diverse new germplasm is being tested in major wheat producing areas, including India, Kenya, Mexico and Pakistan. In Mexico, many of the lines showed increased resistance to abiotic stresses; many lines tested in Pakistan exhibited increased disease resistance; and in India, many tested lines are now part of the national cultivar release system. Overall, national breeding programs have adopted 95 lines for their targeted breeding programs and seven lines are currently undergoing varietal trials.

“This is the first effort of its kind where large-scale pre-breeding efforts have not only enhanced the understanding of exotic genome footprints in bread wheat but also provided practical solutions to breeders,” Sehgal said. “This work has also delivered pre-breeding lines to trait pipelines within national breeding programs.”

Currently, many of these lines are being used in trait pipelines at CIMMYT to introduce these novel genomic regions into advanced elite lines. Researchers are collaborating with physiologists in CIMMYT’s global wheat program to dissect any underlying physiological mechanisms associated with the research team’s findings.

“Our investigation is a major leap forward in bringing genebank variation to the national breeding programs,” Singh explained. “Most significantly, this study sheds light on the importance of international collaborations to bring out successful products and new methods and knowledge to identify useful contributions of exotic in elite lines.”

Read the full article:
Direct introgression of untapped diversity into elite wheat lines

Cover photo: A researcher holds a plant of Aegilops neglecta, a wild wheat relative. Approximately every 20 years, CIMMYT regenerates wheat wild relatives in greenhouses, to have enough healthy and viable seed for distribution when necessary. (Photo: RocĂ­o Quiroz/CIMMYT)

Singh receives lifetime award for wheat breeding successes

Written by Bea Ciordia on . Posted in In the media.

Ravi Singh, head of global wheat improvement at the International Maize and Wheat Improvement Center (CIMMYT), received the 2021 Borlaug Global Rust Initiative (BGRI) Lifetime Achievement Award for his contribution to protecting wheat from new races of some of agriculture’s oldest and most devastating diseases.

Read more: https://www.world-grain.com/articles/16099-singh-receives-lifetime-award-for-wheat-breeding-successes

New CSISA Infographic highlights the impact of the CIMMYT’s Soil Intelligence System (SIS)

Written by Nima Chodon on . Posted in News.

In agriculture, good soil management is a pillar of productive systems that can sustainably produce sufficient and healthy food for the world’s growing population.

Soil properties, however, vary widely across geography. To understand the productive capacity of our soils, we need high-quality data. Soil Intelligence System (SIS) is an initiative to develop comprehensive soil information at scale under the Cereal Systems Initiative for South Asia (CSISA) project in India. SIS is led by the International Maize and Wheat Improvement Centre (CIMMYT) in collaboration with ISRIC – World Soil Information, International Food Policy Research Institute (IFPRI), and numerous local partners on the ground.

Funded by the Gates Foundation, the initiative launched in 2019 helps rationalize the costs of generating high-quality soils data while building accessible geo-spatial information systems based on advanced geo-statistics. SIS is currently operational in the States of Andhra Pradesh, Bihar and Odisha where the project partners collaborate with state government and state agricultural universities help produce robust soil health information.

Farmers are the primary beneficiaries of this initiative, as they get reliable soil health management recommendations to increase yields and profits sustainably while state partners, extension and agricultural development institutions and private sector benefit primarily by expanding their understanding for agricultural interventions.

Modern Soil Intelligence System Impact

CIMMYT’s SIS Project lead Balwinder Singh said, “The Soil Intelligence Systems initiative under CSISA is an important step towards the sustainable intensification of agriculture in South Asia. SIS has helped create comprehensive soil information – digital soil maps – for the states of Andhra Pradesh, Bihar and Odisha. The data generated through SIS is helping stakeholders to make precise agronomy decisions at scale that are sustainable.”

Since its launch in December 2019, a wider network and multi-institutional alliances have been built for soil health management and the application of big data in addressing agricultural challenges. In the three states the infrastructure and capacity of partners have been strengthened to leverage soil information for decision-making in agriculture by devising new soil health management recommendations. For example, in the state of Andhra Pradesh, based on SIS data and outreach, State Fertilizer and Micronutrient Policy (SFMP) recommendations were created. Similarly, soil health management zones have been established to strengthen the fertilizer distribution markets enabling farmers with access and informed choices.

“Soil Intelligence System delivers interoperable information services that are readily usable by emerging digital agricultural decision support systems in India”, noted Kempen Senior Soil Scientist at ISRIC.

The three-part infographic highlights the impact of SIS initiative in the select three States and emphasizes the importance of SIS in other parts of the country as well.