Author Archive

University of Queensland honors student studies tan spot resistance in wheat at CIMMYT

This story, part of a series on the international agricultural research projects of recipients of the Crawford Fund’s International Agricultural Student Award, was originally posted on the Crawford Fund blog

In 2018, Tamaya Peressini, from The Queensland Alliance for Agriculture and Food Innovation (QAAFI), a research institute of the University of Queensland (UQ), travelled to CIMMYT in Mexico as part of her Honours thesis research focused on a disease called tan spot in wheat.

Tamaya performing disease evaluations 10 days post infection at CIMMYT’s glasshouse facilities

Tan spot is caused by the pathogen Pyrenophora triciti-repentis (Ptr), and her project aimed to evaluate the resistance of tan spot in wheat to global races to this pathogen.

“The germplasm I’m studying for my thesis carries what is known as adult plant resistance (or APR) to tan spot, which has demonstrated to be a durable source of resistance in other wheat pathosystems such as powdery mildew,” said Tamaya.

Symptoms of tan spot on wheat plants

Tan spot is prevalent worldwide, and in Australia causes the most yield loss out of the foliar wheat diseases. In Australia, there is only one identified pathogen race that is prevalent called Ptr Race 1. For Ptr Race 1, the susceptibility gene Tsn1 in wheat is the main factor that results in successful infection in Ptr strains that carry Toxin A. However, globally it is a more difficult problem, as there are seven other pathogen races that consist of different combinations of necrotrophic toxins. Hence, developing cultivars that are multi-race resistant to Ptr presents a significant challenge to breeders as multiple resistant genes would be required for resistance to other pathogens.

“At CIMMYT I evaluated the durability of APR I identified in plant material in Australia by inoculating with a local strain of Ptr and also with a pathogen that shares ToxA: Staganospora nodorum.”

“The benefit of studying this at CIMMYT was that I had access to different strains of the pathogen which carry different virulence factors of disease, I was exposed to international agricultural research, and importantly, I was able to create research collaborations that would allow the APR detected in this population to have the potential to reach developing countries to assist in developing durably resistant wheat cultivars for worldwide deployment,” explained Tamaya.

Recent work in Dr Lee Hickey’s laboratory in Queensland has identified several landraces from the Vavilov wheat collection that exhibited a novel resistance to tan spot known as adult plant resistance (APR). APR has proven to be a durable and broad-spectrum source of resistance in wheat crops; namely with the Lr34 gene which confers resistance to powdery mildew and leaf stem rust of wheat.

“My research is focussed on evaluating this type of resistance and identifying whether it is resistant to multiple pathogen species and other races of Ptr. This is important to the Queensland region, as the northern wheat belt is significantly affected by tan spot disease. Introducing durable resistance genes to varieties in this region would be an effective pre-breeding strategy because it would help develop crop varieties that would have enhanced resistance to tan spot should more strains reach Australia. Furthermore, it may provide durable resistance to other necrotrophic pathogens of wheat,” said Tamaya.

The plant material Tamaya studied in her honours thesis was a recombinant inbred line (RIL) population, with the parental lines being the APR landrace (carries Tsn1) and the susceptible Australian cultivar Banks (also carries Tsn1). To evaluate the durability of resistance in this population to other strains of Ptr, this material along with the parental lines of the population and additional land races from the Vavilov wheat collection were sent to CIMMYT for Tamaya to perform a disease assay.

“At CIMMYT I evaluated the durability of APR identified in plant material in Australia by inoculating with a local strain of Ptr and also with a pathogen that shares ToxA: Staganospora nodorum. After infection, my plant material was kept in 100 per cent humidity for 24 hours (12 hours light and 12 hours dark) and then transferred back to regular glasshouse conditions. At 10 days post infection I evaluated the resistance in the plant material.”

From the evaluation, the APR RIL line demonstrated significant resistance compared to the rest of the Australian plant material against both pathogens. The results are highly promising, as they demonstrate the durability of the APR for both pre-breeding and multi-pathogen resistance breeding. Furthermore, this plant material is now available for experimental purposes at CIMMYT where further trials can validate how durable the resistance is to other necrotrophic pathogens and also be deployed worldwide and be tested against even more strains of Ptr.
“During my visit at CIMMYT I was able to immerse myself in the Spanish language and take part in professional seminars, tours, lab work and field work around the site. A highlight for me was learning to prepare and perform toxin infiltrations for an experiment comparing the virulence of different strains of spot blotch.”

“I also formed valuable friendships and research partnerships from every corner of the globe and had valuable exposure to the important research underway at CIMMT and insight to the issues that are affecting maize and wheat growers globally. Of course, there was also the chance to travel on weekends; where I was able to experience the lively Mexican culture and historical sites – another fantastic highlight to the trip!”

Visiting the Sun and Moon temples of Teotihuacan

“I would like to thank CIMMYT and Dr Pawan Singh for hosting me and giving the opportunity to learn, grow and experience the fantastic research that is performed at CIMMYT and opportunities to experience parts of Mexico. The researchers and lab technicians were all so friendly and accommodating. I would also like to thank my supervisor Dr Lee Hickey for introducing this project collaboration with CIMMYT. Lastly, I would like to thank the Crawford Fund Queensland Committee for funding this visit; not only was I able to immerse myself in world class plant pathology research, I have been given valuable exposure to international agricultural research that will give my research career a boost in the right direction,” concluded Tamaya.

A wheat self-sufficiency roadmap for Ethiopia’s future

Mechanization could boost Ethiopian wheat production and provide youth with new job opportunities. (Photo: Gerardo Mejía/CIMMYT)

This blog by Jérôme Bousset was originally posted on CIMMYT.org.

The Ethiopian government announced recently that the country should become wheat self-sufficient over the next four years. Why is boosting domestic wheat production important for this country in the Horn of Africa, and could wheat self-sufficiency be attained in the next four years? The Ethiopian Institute for Agricultural Research (EIAR), with the support of International Maize and Wheat Improvement Center (CIMMYT), gathered agriculture and food experts from the government, research and private sectors on November 23, 2018, to draw the first outlines of this new Ethiopian wheat initiative.

The low-tech domestic wheat farming and price support issue

Despite a record harvest of 4.6 million metric tons in 2017, Ethiopia imported 1.5 million tons of wheat the same year, costing US$600 million. Population growth, continuous economic growth and urbanization over the last decade has led to a rapid change in Ethiopian diets, and the wheat sector cannot keep up with the growing demand for pasta, dabo, ambasha and other Ethiopian breads.

The majority of Ethiopia’s 4.2 million wheat farmers cultivate this cereal on an average of 1.2-hectare holdings, with three quarters produced in Arsi, Bale and Shewa regions. Most prepare the land and sow with draft animal power equipment and few inputs, dependent on erratic rainfall without complementary irrigation. Yields have doubled over the last 15 years and reached 2.7 tons per hectare according to the latest agricultural statistics, but are still far from the yield potential.

According to data from the International Food Policy Research Institute (IFPRI), wheat is preferred by wealthier, urban families, who consume 33 percent more wheat than rural households. Ethiopia needs to rethink its wheat price support system, which does not incentivize farmers and benefits mostly the wealthier, urban consumers. Wheat price support subsidies could, for instance, target bakeries located in poor neighborhoods.

 

Ethiopia’s Minister of Agriculture and Natural Resources, Eyasu Abraha, welcomes conference participants. (Photo: Jérôme Bossuet/CIMMYT)

Where to start to boost wheat productivity?

Ethiopia, especially in the highlands, has an optimum environment to grow wheat. But to make significant gains, the wheat sector needs to identify what limiting factors to address first. The Wheat initiative, led by Ethiopia’s Agricultural Transformation Agency (ATA), has targeted 2,000 progressive farmers across 41 woredas (districts) between 2013 and 2018, to promote the use of improved and recommended inputs and better cropping techniques within their communities. A recent IFPRI impact study showed a 14 percent yield increase, almost enough to substitute wheat imports if scaled up across the country. It is, however, far from the doubling of yields expected initially. The study shows that innovations like row planting were not widely adopted because of the additional labor required.

Hans Braun, WHEAT CGIAR research program and CIMMYT’s Global Wheat Program director, believes Ethiopian farmers can achieve self-sufficiency if they have the right seeds, the right agronomy and the right policy support.

One priority is to increase support for wheat improvement research to make wheat farmers more resilient to new diseases and climate shocks. Drought and heat tolerance, rust resistance and high yields even in low-fertility soils are some of the factors sought by wheat farmers.

International collaboration in durum wheat breeding is urgently needed as the area under durum wheat is declining in Ethiopia due to climate change, diseases and farmers switching to more productive and resilient bread wheat varieties. Braun advises that Ethiopia set up a shuttle breeding program with CIMMYT in Mexico, as Kenya did for bread wheat, to develop high-yielding and stress-resistant varieties. Such a shuttle breeding program between Ethiopia and Mexico would quickly benefit Ethiopian durum wheat farmers, aiming at raising their yields similar to those of Mexican farmers in the state of Sonora, who harvest more than 7 tons per hectare under irrigation. This would require a policy reform to facilitate the exchange of durum germplasm between Ethiopia and Mexico, as it is not possible at the moment.

Ethiopia also needs to be equipped to respond quickly to emerging pests and diseases. Five years ago, a new stem rust (TKTTF, also called Digalu race) damaged more than 20,000 hectares of wheat in Arsi and Bale, as Digalu — the popular variety used by local farmers — was sensitive to this new strain. The MARPLE portable rust testing lab, a fast and cost-effective rust surveillance system, is now helping Ethiopian plant health authorities quickly identify new rust strains and take preventive actions to stop new outbreaks.

CIMMYT’s representative in Ethiopia, Bekele Abeyo, gives an interview for Ethiopian media during the conference. (Photo: Jérôme Bossuet/CIMMYT)

Invest in soil health, mechanization and gender

In addition to better access to improved seeds and recommended inputs, better agronomic practices are needed. Scaling the use of irrigation would certainly increase wheat yields, but experts warn not to dismiss adequate agronomic research — knowing the optimal water needs of the crop for each agroecological zone — and the underlying drainage system. Otherwise, farmers are at risk of losing their soils forever due to an accumulation of salt.

‘’2.5 billion tons of topsoil are lost forever every year due to erosion. A long-term plan to address soil erosion and low soil fertility should be a priority,” highlights Marco Quinones, adviser at ATA. For instance, large-scale lime application can solve the important issue of acid soils, where wheat does not perform well. But it requires several years before the soil can be reclaimed and visible yield effects can be seen.

Mechanization could also boost Ethiopian wheat production and provide youth with new job opportunities. Recent research showed smallholder farmers can benefit from six promising two-wheel tractor (2WT) technologies. Identifying the right business models and setting up adapted training programs and financial support will help the establishment of viable machinery service providers across the country.

Better gender equity will also contribute significantly to Ethiopia becoming self-sufficient in wheat production. Women farmers, especially female-headed households, do not have the same access to trainings, credit, inputs or opportunities to experiment with new techniques or seed varieties because of gender norms. Gender transformative methodologies, like community conversations, can help identify collective ways to address such inequalities, which cost over one percent of GDP every year.

‘’With one third better seeds, one third good agronomy and one third good policies, Ethiopia will be able to be wheat self-sufficient,” concluded Braun. A National Wheat Taskforce led by EIAR will start implementing a roadmap in the coming days, with the first effects expected for the next planting season in early 2019.

The consultative workshop “Wheat Self-Sufficiency in Ethiopia: Challenges and Opportunities” took place in Addis Ababa, Ethiopia, on November 23, 2018.