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
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?