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Combatting soil-borne pathogens and nematodes vital for food security

Written by Sarah McLaughlin on November 7, 2022. Posted in News.

Mustafa Alisarli, Bolu Abant Izzet Baysal University rector, is awarded for hosting this symposium by the representative of the Turkish Ministry of Agriculture and Forestry, General Directorate of Agricultural Research and Policies (GDAR), Dr Suat Kaymak.

The International Maize and Wheat Improvement Center (CIMMYT) coordinated the VIII International Cereal Nematode Symposium between September 26-29, in collaboration with the Turkish Ministry of Agriculture and Forestry, the General Directorate of Agricultural Research and Policies and Bolu Abant Izzet Baysal University.

As many as 828 million people struggle with hunger due to food shortages worldwide, while 345 million are facing acute food insecurity – a crisis underpinning discussions at this symposium in Turkey focused on controlling nematodes and soil-borne pathogens causing reduced wheat yields in semi-arid regions.

A major staple, healthy wheat crops are vital for food security because the grain provides about a fifth of calories and proteins in the human diet worldwide.

Seeking resources to feed a rapidly increasing world population is a key part of tackling global hunger, said Mustafa Alisarli, the rector of Turkey’s Bolu Abant Izzet Baysal University in his address to the 150 delegates attending the VIII International Cereal Nematode Symposium in the country’s province of Bolu.

Suat Kaymak, Head of the Plant Protection Department, on behalf of the director general of the General Directorate of Agricultural Research and Policies (GDAR), delivered an opening speech, emphasizing the urgent need to support the CIMMYT Soil-borne Pathogens (SBP) research. He stated that the SBP plays a crucial role in reducing the negative impact of nematodes and pathogens on wheat yield and ultimately improves food security. Therefore, the GDAR is supporting the SBP program by building a central soil-borne pathogens headquarters and a genebank in Ankara.

Discussions during the five-day conference were focused on strategies to improve resilience to the Cereal Cyst Nematodes (Heterodera spp.) and Root Lesion Nematodes (Pratylenchus spp.), which cause root-health degradation, and reduce moisture uptake needed for proper development of wheat.

Richard Smiley, a professor emeritus at Oregon State University, summarized his research on nematode diseases. He has studied nematodes and pathogenic fungi that invade wheat and barley roots in the Pacific Northwest of the United States for 40 years. “The grain yield gap – actual versus potential yield – in semiarid rainfed agriculture cannot be significantly reduced until water and nutrient uptake constraints caused by nematodes and Fusarium crown rot are overcome,” he said.

Experts also assessed patterns of global distribution, exchanging ideas on ways to boost international collaboration on research to curtail economic losses related to nematode and pathogen infestations.

A special session on soil-borne plant pathogenic fungi drew attention to the broad spectrum of diseases causing root rot, stem rot, crown rot and vascular wilts of wheat.

Soil-borne fungal and nematode parasites co-exist in the same ecological niche in cereal-crop field ecosystems, simultaneously attacking root systems and plant crowns thereby reducing the uptake of nutrients, especially under conditions of soil moisture stress.

Limited genetic and chemical control options exist to curtail the damage and spread of these soil-borne problems which is a challenge exacerbated by both synergistic and antagonistic interactions between nematodes and fungi.

Nematodes, by direct alteration of plant cells and consequent biochemical changes, can predispose wheat to invasion by soil borne pathogens. Some root rotting fungi can increase damage due to nematode parasites.

Integrated managementFor a holistic approach to addressing the challenge, the entire biotic community in the soil must be considered, said Hans Braun, former director of the Global Wheat Program at CIMMYT.

Braun presented efficient cereal breeding as a method for better soil-borne pathogen management. His insights highlighted the complexity of root-health problems across the region, throughout Central Asia, West Asia and North Africa (CWANA).

Richard A. Sikora, Professor emeritus and former Chairman of the Institute of Plant Protection at the University of Bonn, stated that the broad spectrum of nematode and pathogen species causing root-health problems in CWANA requires site-specific approaches for effective crop health management. Sikora added that no single technology will solve the complex root-health problems affecting wheat in the semi-arid regions. To solve all nematode and pathogen problems, all components of integrated management will be needed to improve wheat yields in the climate stressed semi-arid regions of CWANA.

Building on this theme, Timothy Paulitz, research plant pathologist at the United States Department of Agriculture Agricultural Research Service (USDA-ARS), presented on the relationship between soil biodiversity and wheat health and attempts to identify the bacterial and fungal drivers of wheat yield loss. Paulitz, who has researched soil-borne pathogens of wheat for more than 20 years stated that, “We need to understand how the complex soil biotic ecosystem impacts pathogens, nutrient uptake and efficiency and tolerance to abiotic stresses.”

Julie Nicol, former soil-borne pathologist at CIMMYT, who now coordinates the Germplasm Exchange (CAIGE) project between CIMMYT and the International Center for Agricultural Research in the Dry Areas (ICARDA) at the University of Sydney’s Plant Breeding Institute, pointed out the power of collaboration and interdisciplinary expertise in both breeding and plant pathology. The CAIGE project clearly demonstrates how valuable sources of multiple soil-borne pathogen resistance in high-yielding adapted wheat backgrounds have been identified by the CIMMYT Turkey program, she said. Validated by Australian pathologists, related information is stored in a database and is available for use by Australian and international breeding communities.

Economic losses

Root-rotting fungi and cereal nematodes are particularly problematic in rainfed systems where post-anthesis drought stress is common. Other disruptive diseases in the same family include dryland crown and the foot rot complex, which are caused mainly by the pathogens Fusarium culmorum and F. pseudograminearum.

The root lesion nematode Pratylenchus thornei can cause yield losses in wheat from 38 to 85 percent in Australia and from 12 to 37 percent in Mexico. In southern Australia, grain losses caused by Pratylenchus neglectus ranged from 16 to 23 percent and from 56 to 74 percent in some areas.

The cereal cyst nematodes (Heterodera spp.) with serious economic consequences for wheat include Heterodera avenae, H. filipjevi and H. latipons. Yield losses due to H. avenae range from 15 to 20 percent in Pakistan, 40 to 92 percent in Saudi Arabia, and 23 to 50 percent in Australia.

In Turkey, Heterodera filipjevi has caused up to 50 percent crop losses in the Central Anatolia Plateau and Heterodera avenae has caused up to 24 percent crop losses in the Eastern Mediterranean.

The genus Fusarium which includes more than a hundred species, is a globally recognized plant pathogenic fungal complex that causes significant damage to wheat on a global scale.

In wheat, Fusarium spp. cause crown-, foot-, and root- rot as well as head blight. Yield losses from Fusarium crown-rot have been as high as 35 percent in the Pacific Northwest of America and 25 to 58 percent in Australia, adding up losses annually of $13 million and $400 million respectively, due to reduced grain yield and quality. The true extent of damage in CWANA needs to be determined.

Abdelfattah Dababat, CIMMYT’s Turkey representative and leader of the soil-borne pathogens research team said, “There are examples internationally, where plant pathologists, plant breeders and agronomists have worked collaboratively and successfully developed control strategies to limit the impact of soil borne pathogens on wheat.” He mentioned the example of the development and widespread deployment of cereal cyst nematode resistant cereals in Australia that has led to innovative approaches and long-term control of this devastating pathogen.

Dababat, who coordinated the symposium for CIMMYT, explained that, “Through this symposium, scientists had the opportunity to present their research results and to develop collaborations to facilitate the development of on-farm strategies for control of these intractable soil borne pathogens in their countries.”

Paulitz stated further that soil-borne diseases have world-wide impacts even in higher input wheat systems of the United States. “The germplasm provided by CIMMYT and other international collaborators is critical for breeding programs in the Pacific Northwest, as these diseases cannot be managed by chemical or cultural techniques,” he added.

Closing ceremony of the International Cereal Nematode Symposium. From left to right; Hans Braun, Brigitte Slaats, Richard Sikora, Grant Hollaway, Mesut Keser, Zahra Maafi, Richard Smiley, Mustafa Imren, Fatih Ozdemir, Amer Dababat. (Photo: CIMMYT)

Road ahead

Delegates gained a greater understanding of the scale of distribution of cereal cyst nematodes and soil borne pathogens in wheat production systems throughout West Asia, North Africa, parts of Central Asia, Northern India, and China.

After more than 20 years of study, researchers have recognized the benefits of planting wheat varieties that are more resistant. This means placing major emphasis on host resistance through validation and integration of resistant sources using traditional and molecular methods by incorporating them into wheat germplasm for global wheat production systems, particularly those dependent on rainfed or supplementary irrigation systems.

Sikora stated that more has to be done to improve Integrated Pest Management (IPM), taking into consideration all tools wherever resistant is not available. Crop rotations for example have shown some promise in helping to mitigate the spread and impact of these diseases.

“In order to develop new disease-resistant products featuring resilience to changing environmental stress factors and higher nutritional values, modern biotechnology interventions have also been explored,” Alisarli said.

Brigitte Slaats and Matthias Gaberthueel, who represent Swiss agrichemicals and seeds group Syngenta, introduced TYMIRIUM® technology, a new solution for nematode and crown rot management in cereals. “Syngenta is committed to developing novel seed-applied solutions to effectively control early soil borne diseases and pests,” Slaats said.

It was widely recognized at the event that providing training for scientists from the Global North and South is critical. Turkey, Austria, China, Morocco, and India have all hosted workshops, which were effective in identifying the global status of the problem of cereal nematodes and forming networks and partnerships to continue working on these challenges.

Seed company workers emasculating and crossing hybrid tomato seeds. (Photo: Hari Shrestha/CIMMYT)

Ready for the seed sector

Written by Rodrigo Ordóñez on March 26, 2020. Posted in Features.

Nepal’s National Seed Vision 2013-2025 identified the critical skills and knowledge gaps in the seed sector, across the value chain. Seed companies often struggle to find skilled human resources in hybrid product development, improved seed production technology and seed business management. One of the reasons is that graduates from agricultural universities might be missing on recent advancements in seed science and technology, required by the seed industry.

Researchers from the International Maize and Wheat Improvement Center (CIMMYT) have been collaborating with Agriculture and Forestry University (AFU) to review and update the existing curriculum on seed science and technology, for both undergraduate and postgraduate students. This work is part of the Nepal Seed and Fertilizer (NSAF) project, funded by the United States Agency for International Development (USAID) through the Feed the Future initiative.

Realizing the need to increase trained human resources in improved seed technologies, CIMMYT researchers held discussions with representatives from the Department of Agronomy at AFU, to begin revising the curriculum on seed science and technology. Developed four years ago, the current curriculum does not encompass emerging developments in the seed industry. These include, for example, research and product development initiated by local private seed companies engaged in hybrid seed production of various crops, who want to be more competitive in the existing market.

Each year, approximately 200 bachelor’s and 10 master’s students graduate from AFU. In collaboration with CIMMYT, the university identified critical areas that need to be included in the existing curriculum and drafted new courses for endorsement by the academic council. AFU also developed short-term certificate and diploma courses in the subject of seed science and technology.

AbduRahman Beshir, CIMMYT, discusses the importance of linking academic courses with the emerging trends of the seed industry. (Photo: Bandana Pradhan/CIMMYT)

Shared knowledge

On November 20, 2019, CIMMYT, AFU and Catholic Relief Services (CRS) organized a consultation workshop with seed stakeholders from the public and private sectors, civil society and academia. Participants discussed emerging needs within Nepal’s seed industry and charted out how higher education can support demand, through a dynamic and responsive program.

Sabry G. Elias, professor at Oregon State University (OSU), discussed recent advances in seed science and technology, and how to improve productivity of smallholder farmers in Nepal. He is supporting the curriculum revision by taking relevant lessons from OSU and adapting them to Nepal’s context. Sabry shared the courses that are to be included in the new program and outlined the importance of linking graduate research with the challenges of the industry. He also stressed the importance of building innovation and the continuous evolution of academic programs.

Sabry Elias, Oregon State University, talks about the importance of critical thinking to bring innovations to the seed sector. (Photo: Bandana Pradhan/CIMMYT)

Professors from AFU, Nepal Polytechnic Institute, Tribhuvan University, and several private colleges introduced the current courses in seed science and technology at their institutions. Santosh Marahatta, head of the Department of Agronomy at AFU, discussed the limitations of the current master’s and doctoral degree programs, and proposed a draft curriculum with integrated courses across the seed value chain. J.P. Dutta, dean of the Faculty of Agriculture at AFU, shared plans to create a curriculum that would reflect advanced practices and experiences in seed science and technology.

Scientists and researchers from Nepal Agricultural Research Council (NARC) presented their activities and suggested key areas to address some of the challenges in the country’s seed sector.

“Our aim is to strengthen local capacity to produce, multiply and manage adequate quality seeds that will help improve domestic seed production and seed self-sufficiency,” said Mitraraj Dawadi, a representative from the Seed Entrepreneurs Association of Nepal (SEAN). “Therefore, we encourage all graduates to get hands-on experience with private companies and become competent future scientists and researchers.”

AbduRahmann Beshir, Seed Systems Lead for the NSAF project at CIMMYT, shared this sentiment. According to him, most current graduates lack practical experience on hybrid seed development, inbred line maintenance and knowledge on the general requirements of a robust seed industry. “It is important that universities can link their students to private seed companies and work together towards a common goal,” he explained. “This human resource development drive is part of CIMMYT’s efforts to help Nepal on its journey to self-reliance.”

Organizers of the stakeholder consultation workshop to enhance the role of higher learning institutions in the Nepal seed sector at AFU, Chitwan. (Photo: Bandana Pradhan/CIMMYT)

Maximino Alcalá de Stefano working at CIMMYT's wheat international nurseries. (Photo: CIMMYT)

Remembering Max Alcalá, who led CIMMYT’s wheat international nurseries

Written by Mike Listman on August 29, 2019. Posted in News.

The International Maize and Wheat Improvement Center (CIMMYT) sadly notes the passing of Maximino Alcalá de Stefano, former head of the center’s Wheat International Nurseries service, on August 27. He was 80 years old.

Fondly known as “Max” by friends and colleagues, Alcalá worked at CIMMYT from 1967 to 1992, coordinating wheat international nurseries during the late 1960s and early 1970s. The job included organizing nursery shipments to over 100 partners worldwide each year and collating, analyzing, and sharing results from the nurseries grown.

Maximino Alcalá de Stefano passed away at the age of 80 in Houston, Texas, USA. (Photo: Alcalá family)

The printed international nursery report featured an introductory section that described the nurseries, the locations, the statistical analyses used, and an overview of the performance of the breeding lines tested, which comprised the best CIMMYT materials but also germplasm from other sources. The report also carried tables with full data from each location as well as summary tables.

“Max was instrumental in preparing and distributing the printed nursery results, now made available online but which continue to provide crucial input for breeding by CIMMYT and partners,” said Hans-Joachim Braun, director of CIMMYT’s Global Wheat Program. “He also helped start the international nursery database.”

A native of Mexico, Alcalá completed a bachelor’s in Science at the Universidad Autónoma Agraria Antonio Narro in 1964 and a master’s at Texas A&M University in 1967. Alcalá pursued doctoral studies in wheat breeding at Oregon State University under the guidance of renowned OSU researcher Warren E. Kronstad, finishing in 1974.

Maximino Alcalá de Stefano (second from right) worked closely with Nobel Prize winner Norman Borlaug (third from left). In the photo, a group of CIMMYT Scientists during a visit to Nepal in 1978. (Photo: CIMMYT)

His professional experience prior to CIMMYT included appointments at Mexico’s National Institute of Agricultural Research (INIA) and in the national extension services.

Later in his career, Alcalá supported wheat training at CIMMYT and helped coordinate visitors services at CIMMYT’s experimental station near Ciudad Obregón, in Mexico’s Sonora state.

The CIMMYT community sends its deepest sympathies and wishes for peace to the Alcalá family.

International Winter Wheat Improvement Program (IWWIP)

Written by Courtney Brantley on April 12, 2019. Posted in Uncategorized.

The International Wheat Improvement Program was established as a cooperative international research effort by the Turkish national wheat research program and the International Maize and Wheat Improvement Center (CIMMYT) in 1986. The International Center for Agricultural Research in the Rural Areas (ICARDA) joined the program in 1990, integrating its highland wheat breeding program.

The main objective of IWWIP is to develop winter/facultative wheat germplasm for the region of Central and West Asia. IWWIP is fully integrated into the national Turkish wheat program, with a strong connection to partners within and outside the region, such as eastern Europe and the United States.

The program is governed by a steering committee. Three coordinators — Beyhan Akin from CIMMYT, Mesut Keser from ICARDA and Fatih Ozdemir from the Turkish national wheat research program — provide technical leadership.

IWWIP focuses on the development of elite wheat lines for rainfed and irrigated areas in Central and West Asia.

Since the inception of the program, more than 105 winter wheat varieties originating from IWWIP germplasm have been released. Germplasm from IWWIP is sent each year to approximately 100 cooperators in 50 countries, making it an important vehicle for the global exchange of winter wheat germplasm.

Core traits for rainfed areas are yield and yield stability, drought and heat tolerance, resistance to three cereal rusts and soil-borne diseases — nematodes, crown and root rots —, and end-use quality. Other traits considered for specific areas are resistance to Septoria leaf blight and insects. For irrigated and high-rainfall areas, breeding focuses on yield potential, cereal rusts, Septoria and quality.

Germplasm with special traits, such as resistance to stem rust and Russian wheat aphid, and Sun pest vegetative stage resistance, is developed in nurseries and shared with IWWIP cooperators. IWWIP distributes four International Winter Wheat Nurseries each year, targeted for semiarid and irrigated conditions: Facultative and Winter Wheat Observation Nurseries (FAWWONs) FAWWON-SA and FAWWON-IRR, and the replicated International Winter Wheat Yield Trials (IWWYTs) IWWYT-SA and IWWYT-IRR.

In 2018, IWWIP established a speed-breeding facility at the Aegean Agricultural Research Institute in Menemen, Izmir, with the capacity to grow 20,000 plants in one cycle. This facility allows for greater genetic gain by increasing the number of generations per year and reducing the time it takes to incorporate new traits into elite germplasm.

IWWIP uses multi-location testing in Turkey as well as shuttle breeding globally, serving as a successful model for a jointly operated breeding program between national and international institutes. Shuttle breeding to improve drought and heat tolerance and cold tolerance has been working well and produces novel germplasm with abiotic stresses tolerance.

Major IWWIP contributions:

Close cooperation with CIMMYT’s Soil Borne Pathogens Group to identify genotypes with resistance to nematodes and root rots, used in breeding programs in the region and beyond.
A national inventory of wheat landraces in Turkey (2009-2014), with collections from over 1,500 farmers from 68 provinces. The collected material was characterized and deposited in the Turkish Gene Bank in Ankara. The best accessions are currently used as parents, undergoing further study by the Turkish National Program and IWWIP, and being used in the development of primary synthetic winter wheat for breeding diverse and resilient wheat varieties.
High-quality data that has increased selection efficiency to develop yellow-rust-resistant cultivars.
Substantial improvement in stem rust resistance through shuttle methodology between Turkey and Kenya.
Publication of NDVI and digital photos for germplasm evaluation under irrigated and drought conditions.

IWWIP has played a major role in building the capacity of young researchers through long-term practical training at CIMMYT, ICARDA, and Turkish national wheat breeding programs; participation in traveling seminars; support for participation in regional conferences and IWWIP annual meetings; and on-site visits of IWWIP breeders.