By Jennifer Johnson, Terry Molnar and Martha Willcox
Felix Corzo Jimenez , a farmer in Chiapas, Mexico, examines one of his many maize plants infected with tar spot complex.
In southern Mexico and Central America a fungal maize disease known as tar spot complex (TSC) is decimating yields, threatening local food security and livelihoods. In El Portillo, Chiapas, Mexico, local farmer Felix Corzo Jimenez surveys his maize field sadly… “It’s been a terrible year. We’ll be lucky if we harvest even 50 percent of our usual yields.” He fingers a dried up maize leaf covered in tiny black dots, and pulls the husk off of an ear to show the shriveled kernels, poorly filled-in. “Tar spot is ruining our crops.”
Named for the telltale black spots that cover infected plants, TSC causes leaves to die prematurely, weakening the plant and preventing the ears from developing fully, cutting yields by up to 50 percent or more in extreme cases. Caused by a combination of 3 fungal infections, the disease occurs most often in cool and humid areas across southern Mexico, Central America and into South America. The disease is beginning to spread, possibly due to climate change, evolving pathogens and susceptible maize varieties, and was reported in important maize producing regions of central Mexico and the northern United States for the first time last fall. To develop the TSC resistant maize varieties that farmers need, the Seeds of Discovery (SeeD) initiative is working to “mine” the CIMMYT genebank for native maize varieties that may hold genes for resistance against the disease.
The CIMMYT germplasm bank is the lifeblood of many Seeds of Discovery (SeeD) activities, preserving the genetic diversity that is necessary to develop improved maize and wheat varieties with novel genetic variation to feed a growing population in a changing environment.
The bank contains over 170,000 wheat and 28,000 maize seed collections from across the world. These collections represent the genetic diversity of unique native varieties and wild relatives of maize and wheat and are held under long-term storage for the benefit of humanity in accordance with the 2007 International Treaty on Plant Genetic Resources for Food and Agriculture. The collections are also studied and used as a source of diversity to breed for crucial traits such as heat and drought tolerance, resistance to crop diseases and pests, grain yield productivity and grain quality. Seed is freely shared on request to researchers, students, and academic and development institutions worldwide.
To learn more about the history of the CIMMYT germplasm bank, as well as their recent activities and accomplishments, please click here:
If you have ever received seed from the CIMMYT maize germplasm bank, please fill out their customer follow-up survey for the maize germplasm bank here and the wheat germplasm bank here
Calling all post-graduate students interested in genetic diversity! Graduate students working with The International Maize and Wheat Improvement Center (CIMMYT) will be holding an international symposium, “Genetic Diversity: The key to modern crop improvement and food security,” at CIMMYT headquarters in Texcoco, Mexico on 25 and 26 August. The symposium is open to post-graduate students interested in plant breeding and genetic diversity, and will be held in both Spanish and English with simultaneous translation available.
This event is part of the DuPont Plant Sciences Symposia series, established in 2008, and is one of nearly 20 DuPont Pioneer symposia that will be held this year across the world. Organized for, and by postgraduate students, these symposia allow student organizers to gain valuable skills and experience in event organization. The students are organizing this event with the support of by Gilberto Salinas, head of capacity Development at the Seeds of Discovery (SeeD) initiative, and Tabare Abadie, lead of Research Effectiveness at DuPont Pioneer.
By Mike Listman
Sukhwinder Singh at a field of Punjab Agricultural University, India, with Mexican wheat landrace evaluation trial (foreground) and wheat lines derived from the landraces (background). Photo: Mike Listman
For the first time ever, a research team from China, India, Mexico, Uruguay, and the USA has genetically characterized a collection of 8,400 centuries-old Mexican wheat landraces adapted to varied and sometimes extreme conditions, offering a treasure trove of potential genes to combat wheat’s climate-vulnerability.
Reported today in Nature Scientific Reports and led by scientists from the Seeds of Discovery project (SeeD) at the Mexico-based International Maize and Wheat Improvement Center (CIMMYT), the study details critical genetic information about Mexican landraces for use in breeding to boost global wheat productivity.
This is essential, given the well-documented climate effects that imperil key wheat-growing areas, according to scientist Sukhwinder-Singh, SeeD wheat researcher at CIMMYT and corresponding author for the study.
“The landraces, known as Creole wheats, were brought to Mexico as early as the 16th Century,” said Sukhwinder-Singh, who also credited the study to MasAgro, a long-term rural development project between Mexico’s Ministry of Agriculture (SAGARPA) and CIMMYT. “Wheat is not native to Mexico, but this gave the Creoles time to toughen in zones where late-season temperatures can hit highs of 40 degrees Centigrade (104 degrees Fahrenheit).”
Heat can wreak havoc with wheat’s ability to produce plump, well-filled grains. Research has shown that wheat yields plummet 6 percent for each 1-degree-Centigrade rise in temperature, and that warming is already holding back yield gains in wheat-growing mega-regions such as South Asia, home to more than 300 million undernourished people and whose inhabitants consume over 100 million tons of wheat each year.
“Typically, massive seed collections constitute ‘black boxes’ that scientists have long believed to harbor useful diversity but whose treasures have remained scarcely utilized, mostly because we have limited information about them,” explains Prashant Vikram, CIMMYT scientist and first author of the report. “New technologies are helping us to shine a light in the dark corners. As part of MasAgro’s ‘Seeds of Discovery Component,’ the team used the latest genotyping-by-sequencing technology and created unique sets of the landrace collections that together capture nearly 90 percent of the rare gene variants, known as ‘alleles.’”
By Katie Lutz
After wheat seeds are planted in the greenhouse, the samples are then harvested and prepared to be sent to the laboratory for DNA extraction and genotyping.
Photographer: CIMMYT/Carolina Sansaloni
With Syria torn apart by civil war, a team of scientists in Mexico and Morocco are rushing to save a vital sample of wheat’s ancient and massive genetic diversity, sealed in seed collections of an international research center formerly based in Aleppo but forced to leave during 2012-13.
The researchers are restoring and genetically characterizing more than 30,000 unique seed collections of wheat from the Syrian genebank of the International Center for Agricultural Research in the Dry Areas (ICARDA), which has relocated its headquarters to Beirut, Lebanon, and backed up its 150,000 collections of barley, fava bean, lentil and wheat seed with partners and in the Global Seed Vault at Svalbard, Norway.
In March 2015, scientists at ICARDA were awarded The Gregor Mendel Foundation Innovation Prize for their courage in securing and preserving their seed collections at Svalbard, by continuing work and keeping the genebank operational in Syria even amidst war.
“With war raging in Syria, this project is incredibly important,” said Carolina Sansaloni, genotyping and DNA sequencing specialist with the Seeds of Discovery (SeeD) project at the Mexico-based International Maize and Wheat Improvement Center (CIMMYT), which is leading work to analyze the samples and locate genes for breeding high-yield, climate resilient wheats. “It would be amazing if we could be just a small part of reintroducing varieties that have been lost in war-torn regions.”
By Jennifer Johnson
Cynthia Ortiz places DNA samples into a thermal cycler in the CIMMYT Biosciences laboratory.
The Seeds of Discovery (SeeD) project seeks to empower the next generation of Mexican scientists to use maize and wheat biodiversity to effectively meet the needs of Mexican agriculture in the future. By providing professional agricultural research and development opportunities for current and future maize and wheat scientists, SeeD works to ensure that the materials they develop will reach those who need them most. For this reason, SeeD is developing a platform of publicly available data and software tools that enable the efficient use of maize and wheat genetic resources. These genetic resources, or biodiversity, include more than 28,000 maize and 140,000 wheat samples, known as accessions, that are conserved in CIMMYT’s seed bank and available to researchers worldwide.
Genetic resources are the raw materials or building blocks used to develop new maize and wheat varieties needed to meet the demands of a growing population in a changing climate. Many of these maize and wheat accessions contain positive traits such as drought tolerance or disease resistance, which, if bred into new varieties, have the potential to improve food security and livelihoods in countries such as Mexico.
However, the specific potential impact of SeeD on Mexican agriculture and society will only be realized if breeders and scientists effectively use the products resulting from the project. By inviting researchers, professors and students to participate in workshops, training courses and diverse research projects, a growing cadre of scientists is learning how to use the databases and software tools developed by SeeD and validating their utility.
“Sharing the knowledge generated by SeeD and making it available to the scientific community will help accelerate the development of new varieties that will benefit long-term food security in Mexico and the world,” said Cynthia Ortiz, a graduate student in biotechnology at the Center for Research and Advanced Studies of the National Polytechnic Institute (CINVESTAV) in Mexico City.
Ortiz is conducting research for her Master of Science thesis mentored by SeeD scientist Sukhwinder Singh, who is helping her map the quantitative trait loci (QTL) for phenological and grain yield-related traits in wheat varieties created by crossing synthetic wheat varieties with elite lines. She has participated in two SeeD workshops focusing on wheat phenotyping for heat, drought and yield as well as on the use of the maize and wheat molecular atlas, where she learned to use SeeD software such as Flapjack and CurlyWhirly to visualize the results of genetic diversity analyses.
“The materials SeeD has developed have opened the door for identifying genetic resources with positive traits such as heat and drought tolerance, or resistance to pests and diseases that affect crops all over the world,” Ortiz said. “And the best part is that at the same time, they have sought to protect the genetic diversity of these crops, using the native biodiversity we have in Mexico and the world to confront the challenge of ensuring food security.”
David Gonzalez (L) scores maize plants for signs of tar spot disease alongside SeeD scientist Terence Molnar (R) in the state of Chiapas, Mexico.
David Gonzalez, a recent graduate of the Chapingo Autonomous University in Texcoco, a city about 30 km (20 miles) from Mexico City, agrees. He worked with SeeD scientists Sarah Hearne and Terence Molnar on his Master of Science thesis research, identifying genetic resources with resistance to the maize leaf disease “tar spot complex” (TSC) by using genome-wide association study (GWAS) and genomic selection.
“The software and databases SeeD develops for analyzing genotypic and phenotypic data are novel tools that can be used for research as well as academic purposes,” Gonzalez said. “They are a valuable resource that can be utilized by academic institutions to train students in genetic analysis.”
Gonzalez attended the CIMMYT training course “Technologies for Tropical Maize Improvement,” where he learned about new tools for field trial design, data analysis, doubled haploid technology, molecular markers, GWAS and genomic selection.
“This training, as well as the valuable help and support from CIMMYT scientists, really helped me develop myself professionally,” he said. “It was exciting to work with such an ambitious project, doing things that have never been done before to discover and utilize maize and wheat genetic diversity for the benefit of farmers. I look forward to using what I’ve learned in my future career to develop varieties that meet the needs of farmers in Latin America.”
SeeD is a joint initiative of CIMMYT and the Mexican Ministry of Agriculture (SAGARPA) through theMasAgro project. SeeD receives additional funding from the CGIAR Research Programs on Maize (MAIZE CRP) and Wheat (WHEAT CRP), and from the UK’s Biotechnology and Biological Sciences Research Council (BBSRC).
In a world where the population is expected to reach 9 billion by the year 2050, grain production must increase to meet rising demand. This is especially true for bread wheat, which provides one-fifth of the total calories consumed by the world’s population. However, climate change threatens to derail global food security, as instances of extreme weather events and high temperatures reduce agricultural productivity and are increasing faster than agriculture can naturally adapt, leaving our future ability to feed the global population uncertain. How can we ensure crop production and food security for generations to come?