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Tag: wheat rust

Smallholder farmers’ multi-front strategy combats rapidly evolving wheat rust in Ethiopia

 

Ethiopian wheat planting. (Photo: CIMMYT)

New research shows that smallholder farmers in Ethiopia used various coping mechanisms apart from fungicides in response to the recent wheat rust epidemics in the country. Scientists from the International Maize and Wheat Improvement Center (CIMMYT) and the Ethiopian Institute of Agricultural Research (EIAR) call for continuous support to research and extension programs to develop and disseminate improved wheat varieties with resistant traits to old and newly emerging rust races.

Rising wheat yields cannot catch up rising demand

Wheat is the fourth largest food crop in Ethiopia cultivated by smallholders, after teff, maize and sorghum. Ethiopia is the largest wheat producer in sub-Saharan Africa and average farm yields have more than doubled in the past two decades, reaching 2.74 tons per hectare on average in 2017/18. Farmers who use improved wheat varieties together with recommended agronomic practices recorded 4 to 6 tons per hectare in high-potential wheat growing areas such as the Arsi and Bale zones. Yet the country remains a net importer because demand for wheat is rapidly rising.

The Ethiopian government has targeted wheat self-sufficiency by 2023 and the country has huge production potential due to its various favorable agroecologies for wheat production.

However, one major challenge to boosting wheat production and yields is farmers’ vulnerability to rapidly evolving wheat diseases like wheat rusts.

The Ethiopian highlands have long been known as hot spots for stem and yellow wheat rusts caused by the fungus Puccinia spp., which can spread easily under favorable climatic conditions. Such threats may grow with a changing climate.

Recurrent outbreaks of the two rusts destroyed significant areas of popular wheat varieties. In 2010, a yellow rust epidemic severely affected the popular Kubsa variety. In 2013/14, farmers in the Arsi and Bale zones saw a new stem rust race destroy entire fields of the bread wheat Digalu variety.

In response to the 2010 yellow rust outbreak, the government and non-government organizations, seed enterprises and other development supporters increased the supply of yellow rust resistant varieties like Kakaba and Danda’a.

Fungicide is not the only solution for wheat smallholder farmers

Two household panel surveys during the 2009/10 main cropping season, before the yellow rust epidemic, and during the 2013/14 cropping season analyzed farmers’ exposure to wheat rusts and their coping mechanisms. From the survey, 44% of the wheat farming families reported yellow rust in their fields during the 2010/11 epidemic.

Household data analysis looked at the correlation between household characteristics, their coping strategies against wheat rust and farm yields. The study revealed there was a 29 to 41% yield advantage by increasing wheat area of the new, resistant varieties even under normal seasons with minimum rust occurrence in the field. Continuous varietal development in responding to emerging new rust races and supporting the deployment of newly released rust resistant varieties could help smallholders cope against the disease and maintain improved yields in the rust prone environments of Ethiopia.

The case study showed that apart from using fungicides, increasing wheat area under yellow rust resistant varieties, increasing diversity of wheat varieties grown, or a combination of these strategies were the main coping mechanisms farmers had taken to prevent new rust damages. Large-scale replacement of highly susceptible varieties by new rust resistant varieties was observed after the 2010/11 epidemic.

The most significant wheat grain yield increases were observed for farmers who increased both area under resistant varieties and number of wheat varieties grown per season.

The additional yield gain thanks to the large-scale adoption of yellow rust resistant varieties observed after the 2010/11 epidemic makes a very strong case to further strengthen wheat research and extension investments, so that more Ethiopian farmers have access to improved wheat varieties resistant to old and newly emerging rust races.

Read the full study on PLOS ONE:
https://doi.org/10.1371/journal.pone.0219327

Seed production innovations, conservation agriculture and partnerships are key for Africa’s food security

Members of the International Maize Improvement Consortium Africa (IMIC – Africa) and other maize and wheat research partners discovered the latest innovations in seed and agronomy at Embu and Naivasha research stations in Kenya on August 27 and 28, 2019. The International Maize and Wheat Improvement Center (CIMMYT) and the Kenya Agriculture & Livestock Research Organization (KALRO) held their annual partner field days to present sustainable solutions for farmers to cope with poor soils, a changing climate and emerging diseases and pests, such as wheat rust, maize lethal necrosis or fall armyworm.

Versatile seeds and conservation agriculture offer farmers yield stability

“Maize is food in Kenya. Wheat is also gaining importance for our countries in eastern Africa,” KALRO Embu Center Director, Patrick Gicheru, remarked. “We have been collaborating for many years with CIMMYT on maize and wheat research to develop and disseminate improved technologies that help our farmers cope against many challenges,” he said.

Farmers in Embu, like in most parts of Kenya, faced a month delay in the onset of rains last planting season. Such climate variability presents a challenge for farmers in choosing the right maize varieties. During the field days, CIMMYT and KALRO maize breeders presented high-yielding maize germplasm adapted to diverse agro-ecological conditions, ranging from early to late maturity and from lowlands to highlands.

João Saraiva, from the Angolan seed company Jardins d’Ayoba, said having access to the most recent improved maize germplasm is helpful for his young seed company to develop quality seeds adapted to farmers’ needs. He is looking for solutions against fall armyworm, as the invasive species is thriving in the Angolan tropical environment. He was interested to hear about CIMMYT’s progress to identify promising maize lines resistant to the caterpillar. Since fall armyworm was first observed in Africa in 2016, CIMMYT has screened almost 1,200 inbred lines and 2,900 hybrids for tolerance to fall armyworm.

“Hopefully, we will be developing and releasing the first fall armyworm-tolerant hybrids by the first quarter of 2020,” announced B.M. Prasanna, director of CIMMYT’s Global Maize Programme and the CGIAR Research Program on Maize (MAIZE).

“Through continuous innovations to build varieties that perform well despite dry spells, heat waves or disease outbreak, maize scientists have been able to deliver significant yield increases each year across various environments,” explained Prasanna. “This genetic gain race is important to respond to growing grain demands despite growing climate risks and declining soil health.”

Berhanu Tadesse, maize breeder at the Ethiopian Institute for Agricultural Research (EIAR), was highly impressed by the disease-free, impeccable green maize plants at Embu station, remembering the spotted and crippled foliage during a visit more than a decade ago. This was “visual proof of constant progress,” he said.

For best results, smallholder farmers should use good agronomic practices to conserve water and soil health. KALRO agronomist Alfred Micheni demonstrated different tillage techniques during the field tour including the furrow ridge, which is adapted to semi-arid environments because it retains soil moisture.

Late maturity hybrid demonstration plot at Embu station. (Photo: Jérôme Bossuet/CIMMYT)

Innovations for a dynamic African seed sector

A vibrant local seed industry is needed for farmers to access improved varieties. Seed growers must be able to produce pure, high-quality seeds at competitive costs so they can flourish in business and reach many smallholder farmers.

Double haploid technology enables breeders to cut selection cycles from six to two, ultimately reducing costs by one third while ensuring a higher level of purity. Sixty percent of CIMMYT maize lines are now developed using double haploid technology, an approach also available to partners such as the Kenyan seed company Western Seeds.

The Seed Production Technology for Africa (SPTA) project, a collaboration between CIMMYT, KALRO, Corteva Agriscience and the Agricultural Research Council, is another innovation for seed companies enabling cheaper and higher quality maize hybrid production. Maize plants have both female and male pollen-producing flowers called tassels. To produce maize hybrids, breeders cross two distinct female and male parents. Seed growers usually break the tassels of female lines manually to avoid self-pollination. SPTA tested a male sterility gene in Kenya and South Africa, so that female parents did not produce pollen, avoiding a detasseling operation that damages the plant. It also saves labor and boosts seed yields. Initial trial data showed a 5 to 15% yield increase, improving the seed purity as well.

World-class research facilities to fight new and rapidly evolving diseases

The KALRO Naivasha research station has hosted the maize lethal necrosis (MLN) quarantine and screening facility since 2013. Implementing rigorous phytosanitary protocols in this confined site enables researchers to study the viral disease first observed in Africa 2011 in Bomet country, Kenya. Working with national research and plant health organizations across the region and the private sector, MLN has since been contained.

A bird’s eye view of the demonstration plots is the best testimony of the impact of MLN research. Green patches of MLN-resistant maize alternate with yellow, shrivelled plots. Commercial varieties are susceptible to the disease that can totally wipe out the crop, while new MLN-resistant hybrids yield five to six tons per hectare. Since the MLN outbreak in 2011, CIMMYT has released 19 MLN-tolerant hybrids with drought-tolerance and high-yielding traits as well.

Maize Lethal Necrosis (MLN) sensitive and resistant hybrid demo plots in Naivasha’s quarantine & screening facility (Photo: KIPENZ/CIMMYT)

A major challenge to achieving food security is to accelerate the varietal replacement on the market. CIMMYT scientists and partners have identified the lengthy and costly seed certification process as a major hurdle, especially in Kenya. The Principal Secretary of the State Department for Research in the Ministry of Agriculture, Livestock, and Fisheries, Hamadi Boga, pledged to take up this issue with the Kenya Plant and Health Inspectorate Service (KEPHIS).

“Such rapid impact is remarkable, but we cannot rest. We need more seed companies to pick up these new improved seeds, so that our research reaches the maximum number of smallholders,’’ concluded Prasanna.

New platform rapidly diagnoses wheat rust

“Knowing which strain you have is critical information that can be incorporated into early warning systems and results in more effective control of disease outbreaks in farmer’s fields” said Dr. Dave Hodson, a rust pathologist at CIMMYT in Ethiopia and co-author of the paper “MARPLE, a point-of-care, strain-level disease diagnostics and surveillance tool for complex fungal pathogens.” Read more here.

Using the MARPLE kit to diagnose wheat rust in Ethiopia

MARPLE (Mobile and Real-time PLant disEase) Diagnostics is a revolutionary mobile lab developed by a team from the John Innes Centre (JIC), the International Maize and Wheat Improvement Center (CIMMYT) and the Ethiopian Institute of Agricultural Research (EIAR). It uses nanopore sequence technology to rapidly diagnose and monitor wheat rust in farmers’ fields.

Designed to be used without constant electricity and in varying temperatures, the suitcase-sized lab allows researchers to identify wheat rust to strain level in just 48 hours — something that used to take months using other tools.

The MARPLE team was recognized as Innovator of the Year for international impact in 2019 by the UK Biotechnology and Biological Sciences Research Council (BBSRC).

A new video from the John Innes Centre shows how the MARPLE Diagnostics kit will allow Ethiopia to quickly identify wheat rust strains, instead of sending samples to labs abroad.

MARPLE team recognized for international impact

MARPLE team members Dave Hodson and Diane Saunders (second and third from left) stand for a photograph after receiving the International Impact award. With them is Malcolm Skingle, director of Academic Liaison at GlaxoSmithKline (first from left) and Melanie Welham, executive chair of BBSRC. (Photo: BBSRC)
MARPLE team members Dave Hodson and Diane Saunders (second and third from left) stand for a photograph after receiving the International Impact award. With them is Malcolm Skingle, director of Academic Liaison at GlaxoSmithKline (first from left) and Melanie Welham, executive chair of BBSRC. (Photo: BBSRC)

The research team behind the MARPLE (Mobile And Real-time PLant disEase) diagnostic kit won the International Impact category of the Innovator of the Year 2019 Awards, sponsored by the United Kingdom’s Biotechnology and Biological Sciences Research Council (BBSRC).

The team — Diane Saunders of the John Innes Centre (JIC), Dave Hodson of the International Maize and Wheat Improvement Center (CIMMYT) and Tadessa Daba of the Ethiopian Institute for Agricultural Research (EIAR) — was presented with the award at an event at the London Science Museum on May 15, 2019. In the audience were leading figures from the worlds of investment, industry, government, charity and academia, including the U.K.’s Minister of State for Universities, Science, Research and Innovation, Chris Skidmore.

The BBSRC Innovator of the Year awards, now in their 11th year, recognize and support individuals or teams who have taken discoveries in bioscience and translated them to deliver impact. Reflecting the breadth of research that BBSRC supports, they are awarded in four categories of impact: commercial, societal, international and early career. Daba, Hodson and Saunders were among a select group of 12 finalists competing for the four prestigious awards. In addition to international recognition, they received £10,000 (about $13,000).

“I am delighted that this work has been recognized,” Hodson said. “Wheat rusts are a global threat to agriculture and to the livelihoods of farmers in developing countries such as Ethiopia. MARPLE diagnostics puts state-of-the-art, rapid diagnostic results in the hands of those best placed to respond: researchers on the ground, local government and farmers.”

On-the-ground diagnostics

The MARPLE diagnostic kit is the first operational system in the world using nanopore sequence technology for rapid diagnostics and surveillance of complex fungal pathogens in the field.

In its initial work in Ethiopia, the suitcase-sized field test kit has positioned the country — one of the region’s top wheat producers — as a world leader in pathogen diagnostics and forecasting. Generating results within 48 hours of field sampling, the kit represents a revolution in plant disease diagnostics. Its use will have far-reaching implications for how plant health threats are identified and tracked into the future.

MARPLE is designed to run at a field site without constant electricity and with the varying temperatures of the field.

“This means we can truly take the lab to the field,” explained Saunders. “Perhaps more importantly though, it means that smaller, less-resourced labs can drive their own research without having to rely on a handful of large, well-resourced labs and sophisticated expertise in different countries.”

In a recent interview with JIC, EIAR Director Tadessa Daba said, “we want to see this project being used on the ground, to show farmers and the nation this technology works.”

The MARPLE team uses the diagnostic kit in Ethiopia. (Photo: JIC)
The MARPLE team uses the diagnostic kit in Ethiopia. (Photo: JIC)

Development of the MARPLE diagnostic kit was funded by the Biotechnology and Biological Sciences Research Council (BBSRC) and the CGIAR Platform for Big Data in Agriculture’s Inspire Challenge. Continued support is also provided by the BBSRC’s Excellence with Impact Award to the John Innes Centre and the Delivering Genetic Gain in Wheat project, led by Cornell University and funded by the UK’s Department for International Development (DFID) and the Bill & Melinda Gates Foundation.

More information on the award can be found on the JIC website, the BBSRC website and the website of the CGIAR Research Program on Wheat.

Wheat Productivity Enhancement Program (WPEP)

The Wheat Productivity Enhancement Program aims to enhance and protect the productivity of wheat in Pakistan by supporting research that leads to the identification, adoption, and optimal agronomic management of new, high yielding, disease-resistant wheat varieties. The main goal of the project is to facilitate efforts of scientific institutions in Pakistan to minimize adverse effects of wheat rusts — including the highly virulent Ug99 stem rust disease — through surveillance and genetically resistant varieties.

As part of the U.S. government’s assistance to Pakistan, the U.S. Department of Agriculture (USDA) and Pakistan’s Ministry of Agriculture have identified the development of wheat varieties with resistance to virulent rust strains as a goal for improving food security and related agricultural production challenges. This document outlines a project for providing cereal rust protection for wheat production in Pakistan.

This wheat production enhancement project is a multi-partner, collaborative research and development program that includes human resource development. The primary external partners — USDA, CIMMYT, and the International Center for Agricultural Research in the Dry Areas — work cooperatively with Pakistan research organizations to refine work plans and implement research and development activities in rust surveillance, pre-breeding, breeding, seed, and agronomy as described in objectives section.

Objectives

  • Rust pathogen surveillance
  • Pre-breeding to enhance the diversity and utility of rust resistant wheat breeding parent
  • Accelerated breeding to develop and test rust resistant, high performance candidate wheat varieties
  • Seed multiplication and distribution
  • Agronomic management practices

Ethiopia calls for continued collaboration to increase wheat production and meet nutritional and food security

Participants of the project closure workshop stand for a group photo. (Photo: Semu Yemane/EIAR)
Participants of the project closure workshop stand for a group photo. (Photo: Semu Yemane/EIAR)

The Ethiopian wheat sector has seen progress since the early 2000s, more than doubling the average farm yields from 1.13 tons per hectare in 1998/99 to 2.74 tons per hectare in 2017/18. Progressive farmers who plant improved wheat varieties and follow recommended agronomic practices could harvest four to six tons per hectare in high-potential wheat growing areas. However, the production is not keeping up with the growing wheat demand: imports reached over 1.5 million tons last year. The Ethiopian government has announced recently that the country should become wheat self-sufficient over the next four years.

One of the biggest wheat production challenges in Ethiopia has been the stem rust and yellow rust diseases caused by Pucccinia spp, which severely affected popular wheat varieties like Kubsa, Galema and Digalu that wiped out from production.

In response to these losses, the International Maize and Wheat Improvement Center (CIMMYT) started an emergency project to multiply and disseminate rust-resistant wheat varieties in the affected regions in 2014, with support from USAID.

The following year, CIMMYT launched the Seed Multiplication and Delivery of High Yielding Rust Resistant Bread and Durum Wheat Varieties to Ethiopian Farmers project. It benefitted people in 54 woredas (districts) of 4 regions: Amhara, Oromia, SNNP and Tigray. CIMMYT collaborated with the Ethiopian Institute of Agricultural Research (EIAR), regional agricultural research institutes and the regional bureaus of agriculture.

This wheat seed scaling project wrapped up with a closure workshop on March 7, 2019. Organized by CIMMYT and EIAR, it gathered representatives from USAID, policymakers, researchers and other governmental and non-governmental institutions.

State minister of agriculture Aynalem Nigussie officially opened the workshop. (Photo: Semu Yemane/EIAR)
State minister of agriculture Aynalem Nigussie officially opened the workshop. (Photo: Semu Yemane/EIAR)

State minister of agriculture Aynalem Nigussie noted that the project boosted farmers’ productivity thanks to better seeds, improved farming practices and increased knowledge to deal with wheat rust diseases. She recognized that the project aligned with national priorities, as the government is devising a new seed policy to address the current challenges of the Ethiopian wheat seed sector.

CIMMYT’s representative in Ethiopia, Bekele Abeyo, highlighted some of the project outcomes. Some of the achievements in the past four years included the release and demonstration of 23 wheat varieties — 18 bread and 5 durum types —, increased access to these improved seeds for 131,132 households and production of 39,750 tons of wheat grain. Extension agents from 54 woredas participated in training in wheat rust management, recommended agronomic packages for the new wheat varieties, and field data collection and management.

Lessons learned

Abeyo explained that the project could reach a high number of farmers thanks to effective teamwork between the various stakeholders, seed support on revolving bases and a decentralized seed production to reach even remote places. Clustering farmers’ plots favored quality seed production.

Participants flagged weak market linkages, particularly for farmers producing durum wheat, , as a bottleneck to address. Workshop participants recommended the establishment of a wheat task force involving the private sector and with continuous support from funders like USAID.

The director general of EIAR, Mandefro Nigusse, said that the issues raised are inputs for further actions, and some will have to be directed to researchers and breeders to come up with additional solutions for the challenges the wheat sector is facing.

Eyasu Abrha, Advisor to the Minister of Agriculture, officially closed the workshop. He noted that the government of Ethiopia is putting effort into ensuring nutritional and food security, and that projects such as this one are important to address critical challenges in the sector. Abrha acknowledged the support of CIMMYT, EIAR and USAID, and called for a continued collaboration with the government of Ethiopia to meet nutritional and food security goals.

CIMMYT's representative in Ethiopia, Bekele Abeyo, presents the achievements of the project. (Photo: Semu Yemane/EIAR)
CIMMYT’s representative in Ethiopia, Bekele Abeyo, presents the achievements of the project. (Photo: Semu Yemane/EIAR)

CIMMYT trains early career scientists on wheat rust diagnosis and management

NJORO, Kenya (CIMMYT) — The International Maize and Wheat Improvement Center (CIMMYT), in collaboration with Kenya Agricultural & Livestock Research Organization (KALRO) and Cornell University, recently trained 29 scientists from 13 countries on wheat rust disease diagnosis and management techniques, as well as innovative wheat breeding practices. The training, part of the Delivering Genetic Gains in Wheat (DGGW) project, took place on October 1-9, 2018, at the KALRO research station in Njoro, Kenya, where CIMMYT’s wheat breeding and rust screening facility is located.

More than 200 scientists have increased their capacity at these annual trainings since CIMMYT started organizing them ten years ago. The trainings focus particularly on studying resistance to black (stem) rust, yellow (stripe) rust and brown (leaf) rust. Future wheat champions in national agricultural research systems (NARS) get new skills on innovative and cost-effective wheat breeding. These trainings are also a chance for CIMMYT’s Global Wheat Program to establish new partnerships and to collaborate on emerging challenges related to wheat breeding in different farming regions.

“The focus of this year’s event was to train the scientists on how to identify and record notes for stem rust occurrences and how to evaluate wheat material in the field, to better understand how wheat rust pathogens keep evolving,” said Mandeep Randhawa, wheat breeder and wheat rust pathologist at CIMMYT.

Robert McIntosh from University of Sydney's Plant Breeding Institute demonstrates stem rust inoculation using a syringe. (Photo: KALRO)
Robert McIntosh from University of Sydney’s Plant Breeding Institute demonstrates stem rust inoculation using a syringe. (Photo: KALRO)
Scientists Ruth Wanyera (center) and Mandeep Randhawa (right) demonstrate stem inoculation devices. (Photo: KALRO)
Scientists Ruth Wanyera (center) and Mandeep Randhawa (right) demonstrate stem inoculation devices. (Photo: KALRO)
CIMMYT scientist Mandeep Randhawa indicates exact wheat plant stage for stem rust inoculation during the wheat stem rust training. (Photo: KALRO)
CIMMYT scientist Mandeep Randhawa indicates exact wheat plant stage for stem rust inoculation during the wheat stem rust training. (Photo: KALRO)
CIMMYT scientist Mandeep Randhawa explains trainees early booting stage for stem rust inoculation. (Photo: KALRO)
CIMMYT scientist Mandeep Randhawa explains trainees early booting stage for stem rust inoculation. (Photo: KALRO)
Participants of the wheat stem rust training pose for a group photograph. (Photo: KALRO)
Participants of the wheat stem rust training pose for a group photograph. (Photo: KALRO)
Participants of CIMMYT's annual wheat improvement training in Njoro, Kenya, attend a class session. (Photo: KALRO)
Participants of CIMMYT’s annual wheat improvement training in Njoro, Kenya, attend a class session. (Photo: KALRO)

Despite its importance for global food security and nutrition, wheat remains susceptible to endemic and highly destructive rust diseases which can lead to 60-100 percent yield losses. Developing and distributing rust resistant wheat varieties is regarded as the most cost-effective and eco-friendly control measure, especially in developing countries, where the majority are resource-poor smallholder farmers with no access to fungicides to control the disease.

As a global leader in wheat and maize breeding systems, CIMMYT has sustained efforts to develop high-yielding, disease-resistant and stress-tolerant varieties. In partnership with KALRO, CIMMYT identified and released over 15 commercial wheat varieties since the establishment of the stem rust screening facility in Njoro in 2008. Despite the appearance of new devastating strains of stem rust over the period, most of these released wheat varieties are high-yielding with stem rust resistance, according to Randhawa.

“Adequate management practices, including timely planting and application of right fungicides, have kept some of the high-yielding varieties such as Kenya Korongo and Eagle10 in production,” Randhawa explained.

Several high-yielding rust resistant wheat lines are in pipeline for national evaluation to release as wheat varieties in Kenya, he said.

The development of a portable, real-time diagnostics tool for wheat yellow rust, namely the Mobile and Real-time Plant DisEase Diagnostics (MARPLE) was another breakthrough in identifying and combating wheat rust. This mobile plant health diagnosis tool helps identify rust strains in three days instead of months. This is a game changer for the wheat sector, as rust control measures could be deployed before new rust becomes a large-scale epidemic. Led by senior scientist David Hodson, MARPLE is the result of the collaboration between CIMMYT, the Ethiopian Institute of Agricultural Research (EIAR) and the John Innes Centre. There are plans to scale up this innovation in Ethiopia, where it is expected to provide five million wheat farmers a lifeline to control wheat yellow rust.

At the training, participants such as Zafar Ziyaev from Uzbekistan, were glad to gain deeper understanding on how to use modern tools for rust surveillance and the control measures. Others acknowledged the importance of sensitizing and supporting farmers to grow rust-resistant wheat varieties.

Emeritus Professor Robert McIntosh, one of the trainers from the Plant Breeding Institute at the University of Sydney, acknowledged the need for wheat scientists to remain vigilant on rust outbreaks globally and the evolving nature of the pathogens.

“As rust pathogens spread from country to country and region to region, such trainings allow national scientists to learn about the need for constant awareness, the basic principles of epidemiology and genetics that provide the basis of breeding for durable resistance, and what the Njoro rust testing platform can offer to the NARS,” McIntosh said.

Suitcase-sized lab speeds up wheat rust diagnosis

A farm landscape in Ethiopia. (Photo: Apollo Habtamu/ILRI)
A farm landscape in Ethiopia. (Photo: Apollo Habtamu/ILRI)

Despite her unassuming nature, the literary character Miss Marple solves murder mysteries with her keen sense of perception and attention to detail. But there’s another sleuth that goes by the same name. MARPLE (Mobile And Real-time PLant disEase) is a portable testing lab which could help speed-up the identification of devastating wheat rust diseases in Africa.

Rust diseases are one of the greatest threats to wheat production around the world. Over the last decade, more aggressive variants that are adapted to warmer temperatures have emerged. By quickly being able to identify the strain of rust disease, researchers and farmers can figure out the best course of action before it is too late.

The Saunders lab of the John Innes Centre created MARPLE. In collaboration with the Ethiopian Institute of Agricultural Research (EIAR) and the International Maize and Wheat Improvement Center (CIMMYT), researchers are testing the mobile diagnostic kit in Holeta, central Ethiopia.

“These new pathogen diagnostic technologies … offer the potential to revolutionize the speed at which new wheat rust strains can be identified,” says Dave Hodson, a CIMMYT rust pathologist in Ethiopia. “This is critical information that can be incorporated into early warning systems and result in more effective control of disease outbreaks in farmers’ fields.”

Hodson and his colleagues will be presenting their research at the CGIAR Big Data in Agriculture Convention in Nairobi, on October 3-5, 2018.

Read more about the field testing of the MARPLE diagnostic kit on the ACACIA website.

Deadly strain of wheat stem rust disease surfaces in Europe

Wheat stem rust was reported by the Greeks and Romans, and the latter sacrificed to the gods to avoid disease outbreaks on their wheat crops. Photo: CIMMYT/Petr Kosina
Wheat stem rust was reported by the Greeks and Romans, and the latter sacrificed to the gods to avoid disease outbreaks on their wheat crops.
Photo: CIMMYT/Petr Kosina

As reported today in Communications Biology, an international team of researchers led by the John Innes Centre, U.K., found that 80 percent of U.K. wheat varieties are susceptible to the deadly stem rust strain. The group also confirmed for the first time in many decades that the stem rust fungus was growing on barberry bush, the pathogen’s alternate host, in the UK.

“This signals the rising threat of stem rust disease for wheat and barley production in Europe,” said Dave Hodson, senior scientist at the International Maize and Wheat Improvement Center (CIMMYT) and co-author on the study.

A scourge of wheat since biblical times, stem rust caused major losses to North American wheat crops in the early 20th century. Stem rust disease was controlled for decades through the use of resistant wheat varieties bred in the 1950s by scientist Norman Borlaug and his colleagues. Widespread adoption of those varieties sparked the Green Revolution of the 1960s and 70s.

In 1999 a new, highly-virulent strain of the stem rust fungus emerged in eastern Africa. Spores of that strain and variants have spread rapidly and are threatening or overcoming the genetic resistance of many currently sown wheat varieties. Scientists worldwide joined forces in the early 2000s to develop new, resistant varieties and to monitor and control outbreaks of stem rust and yellow rust, as part of collaborations such as the Borlaug Global Rust Initiative led by Cornell University.

Barberry is a shrub found throughout the temperate and subtropical regions. Photo: CIMMYT archives
Barberry is a shrub found throughout the temperate and subtropical regions. Photo: John Innes Centre

The Communications Biology study shows that 2013 U.K. stem rust strain is related to TKTTF, a fungal race first detected in Turkey that spread across the Middle East and recently into Europe. It was the dominant race in the 2013 stem rust outbreak in Germany and infected 10,000 hectares of wheat in Ethiopia’s breadbasket the same year.

Because disease organisms mutate quickly to overcome crop resistance controlled by single genes, researchers are rushing to identify new resistance genes and to incorporate multiple genes into high-yielding varieties, according to Ravi Singh, CIMMYT wheat scientist who participated in the reported study.

“The greatest hope for achieving durable resistance to rust diseases is to make wheat’s resistance genetically complex, combining several genes and resistance mechanisms,” Singh explained.

Barberry, which serves as a spawning ground for the stem rust fungus, was largely eradicated from the U.K. and U.S. last century, greatly reducing the spread and genetic diversification of rust disease races. Now barberry is being grown again in the U.K. over the last decade, according to Diane G.O. Saunders, John Innes Centre scientist and co-author of the study.

“The late Nobel laureate Norman Borlaug said that the greatest ally of the pathogen is our short memory,” Saunders stated. “We recommend continued, intensive resistance breeding. We would also welcome work with conservationists of endangered, barberry-dependent insect species to ensure that planting of common barberry occurs away from arable land, thus safeguarding European cereals from a large-scale re-emergence of wheat stem rust.”

Click here to read the John Innes Centre media release about the Communications Biology report and view the report.

CIMMYT scientist cautions against new threats from wheat rust diseases

David Hodson, senior scientist with CIMMYT, trains South Asian wheat scientists on the use of handheld surveillance and monitoring devices. Hodson directs the rusttracker.org global wheat rust monitoring system for the Delivering Genetic Gain in Wheat (DGGW) project. Credit: CORNELL/Linda McCandless

EL BATAN, Mexico (CIMMYT) – Scientists are concerned over the proliferation of highly virulent fungal wheat diseases, including two new races of yellow rust – one in Europe and North Africa, the other taking hold in East Africa and Central Asia – and a new race of stem rust emerging in Europe.

The collaborative Global Rust Reference Center (GRRC) hosted by Aarhus University in Denmark and including the International Maize and Wheat Improvement Center (CIMMYT) and the International Center for Agricultural Research in the Dry Areas (ICARDA), was instrumental in identifying the new races of yellow and stem rust.

A strategic tool developed by David Hodson, a senior scientist with CIMMYT plays a key role in monitoring the movement of wheat-rust pathogens, helping farmers combat the disease in time to save crops and prevent food insecurity.

“We see an alarming increase in severe disease, more disease diversity and rapid spread,” said Hodson, who invented the Rust Tracker field surveillance tool.

Last year, the Italian island of Sicily was badly hit by a strain of wheat stem rust – an event not seen in Europe since the 1950s, following concerted efforts by wheat breeders to eliminate it.

Stem rust appears as a reddish-brown fungal build-up on wheat stems or leaves, stunting and weakening plants, preventing kernels from forming, leading to shriveled grain and potential crop losses of 50 to 100 percent.

Dispersal modeling, undertaken by the University of Cambridge and the UK Met Office, which forecasts weather and climate change, indicates that spores from the Sicilian outbreak could potentially have spread within the Mediterranean wheat growing region, but scientists are unsure whether they will successfully over-winter, surviving and proliferating, according to a recent story in the journal Nature.

EARLY WARNING

“Several factors may be influencing the changes and rapid spread: increased travel and trade; increasing pathogen populations; more uniform cropping systems and also climate change, but the rapid changes we are observing highlight the need for an enhanced early-warning system,” said Hodson, a member of an international team of scientists collaborating under the Delivering Genetic Gain in Wheat (DGGW) project administered by Cornell University through the Borlaug Global Rust Initiative (BGRI).

Scientists engaged with the major four-year international project – which has a budget of $34.5 million due to grants equalling $24 million from the Bill & Melinda Gates Foundation and a recent $10.5 million grant from UK Aid (Britain’s Department for International Development, or DFID) – use comparative genomics and big data to develop new wheat varieties. The aim is to help governments provide smallholder farmers in the developing world with seeds incorporating resilience to environmental stresses and diseases through local entrepreneurial distributors.

“The sooner farmers are notified of a potential rust outbreak, the better chance they have to save their crops through fungicides or by planting resilient wheat varieties,” Hodson said.

“It’s a constant challenge. We’re always on the lookout for new diseases and variants on old diseases to put the wheels in motion to aid governments who can distribute seeds bred specifically to outsmart rusts.”

However, the long-term sustainability of these vital disease-monitoring systems is uncertain. Despite the significant investments, challenges remain, Hodson said.

“It’s worrying that just as stem rust is re-appearing in Europe we’re at risk of losing the only stem rust pathotyping capacity in Europe at GRRC, due to a funding shortfall. Given the threats and changes we are observing, there really is a critical need for a long-term strategy to address major crop diseases.”

TRACKER ORIGINS

The online Rust Tracker was originally conceived as a tool to battle stem rust, including the lethal Ug99 race, which since its discovery in 1998 has spread from Uganda into the Middle East and is now found in 13 countries. If Ug99 takes hold in a field it can completely wipe out a farmer’s crop. In developing countries, farmers have more difficulty accessing and affording fungicides, which can potentially save a crop.

Under the Durable Rust Resistance in Wheat project, the predecessor to the DGGW project, BGRI-affiliated scientists aimed to prevent the spread of Ug99 into the major global breadbaskets of China and India. So far, they have succeeded in keeping it in check and raising awareness among governments and farmers of its potentially devastating impact.

“Researchers and farmers are connected in the global village,” Hodson said. “Plant pathogens know no borders. We must leave no stone unturned in our efforts to understand the dynamics of wheat rusts, how they’re changing, where they’re spreading and why. If wheat scientists can help prevent a food crisis, we’re doing our job to help maintain political and economic stability in the world.”