The Roots of "Hidden Hunger"
For much of history, malnutrition was a caloric problem—people simply weren't getting enough food. But in the last half-century, hunger has changed. People
eat larger quantities of food than their ancestors, but they suffer from severe vitamin and mineral deficiencies, a problem sometimes referred to as
Howarth Bouis, director of HarvestPlus, believes that the roots of these deficiencies may lie in agriculture.
While the Green Revolution of the last century caused cereal yields in the developing world to skyrocket—bringing affordable food to hungry populations—the
productivity of non-staple foods did not make a similar leap. This pushed up prices of foods such as pulses, produce, fish and animal products. As a result, many people in poverty could put more calories on their plate, but at the
expense of getting the diversity of the nutrients they needed.
"Agriculture must play a major role in the solution to vitamin and mineral deficiencies that the food system may have inadvertently caused," Bouis says.
Biofortification could be a crucial component of that solution. About 75 percent of the world's poor live in rural areas, too far from urban hubs to be
effectively reached with supplementation. But giving rural farmers ways to grow their own more nutritious crops can enrich the diet of many.
"It's the power of a seed," Bouis says.
Corn of a Different Color
The research team had to adapt their biofortification efforts to encompass two additional challenges: The corn had to be all-natural to ensure that the
people who needed provitamin A the most would eat it—and a new color was in order.
Consumers in sub-Saharan Africa have a strong cultural preference for white corn, which contains almost no carotenoids. Yellow corn is more nutritious than
white, but it is fed almost exclusively to animals in most African countries. Rocheford's team and colleagues at CIMMYT would have to develop a type of
corn that did not resemble yellow corn in order for the crop to pass the muster of deeply entrenched traditions.
Examining a set of diverse lines of corn from all over the world provided by Ed Buckler of the U.S. Department of Agriculture's Agricultural Research Service, Rocheford noticed that ears of orange
corn from Thailand had naturally high amounts of carotenoids, providing a genetic base with which breeders could work. The distinct color of the corn was
an added benefit.
Rocheford identifies genes that International Maize and Wheat Improvement Center (CIMMYT) plant breeders in Texcoco, Mexico, can select to increase corn’s carotenoid levels. (Photo by Jennifer Stewart)
The team has spent years identifying and characterizing genes in corn's carotenoid biosynthetic pathway in hopes of pinpointing the factors behind
provitamin A production. So far, Rocheford and colleagues at Cornell and Michigan State universities have identified several genes that can be selected to
rapidly convert high-yielding white corn varieties into orange corn that contains large amounts of provitamin A. Breeders at CIMMYT and Rocheford's group
are using the genes to strategically select and breed for varieties that have higher levels of these nutrients and are suitable for Africa's growing
"The faster we can get favorable forms of these genes into orange corn, the faster we can save human lives," he says.
Transgenic biotechnology could potentially speed the biofortification process, but the team was concerned that genetically modifying the corn would prevent
consumers in Africa from accepting it. To sidestep any potential controversy, the team uses natural selection and breeding methods used for thousands of
Their efforts have brought the provitamin A levels in high-yielding, orange corn hybrids up to 12 parts per million, nearly a tenfold increase over levels
in most yellow corn varieties. Experimental lines at CIMMYT that trace back to the orange corn grown at ACRE can contain up to 35 parts per million when
the most favorable form of one of the first identified genes is crossed in.
Testing Corn on African Taste Buds
Three varieties were released in Zambia in 2012, and acceptance studies that measure consumer response to orange corn have been positive, Rocheford says.
HarvestPlus works with local breeders and growers to spread awareness of the corn, its nutritional benefits, and how to grow it. More than 10,000 farming
households in Africa now know about orange corn.
Rocheford's favorite example of orange corn's success is a story told to him by Eliab Mupongwe, the HarvestPlus country manager for Zambia. Mupongwe held a
field day for orange corn and provided local women with enough ground orange corn to make 100 servings of nshima for lunch. But when the meal was served,
there was only one platter of orange nshima, which was offered to dignitaries and politicians—all the other platters had nshima made from white corn. He
asked the kitchen staff what had happened. The head cook replied that when they heard the orange corn contained vitamins, they took it home and fed it to
"That's no statistical test or formal study, but it sums up nicely that there's good potential for consumer acceptance," Rocheford says.
Considering cultural issues in addition to plant genetics and field management practices should be common practice for good plant breeders, he says.
Scientists on the team have had to contend not only with plant biology, but also with consumer behavior, cultural preferences, logistics of seed delivery
and local politics. Rocheford sees all these factors as part of the job.
The HarvestPlus and CIMMYT teams are preparing to introduce orange corn into Zimbabwe and Ethiopia where varieties will need to be able to withstand
drought and the low nitrogen conditions of the soil.
Rocheford's ultimate dream is to see orange corn sown all across sub-Saharan Africa. He also aims to bring orange corn to growers in the U.S. The corn
contains the carotenoids lutein and zeaxanthin, which may help prevent macular degeneration, a leading cause of impaired vision in the elderly. CIMMYT is
now sending him improved versions of the genetic materials he helped discover and develop to cross into Midwestern corn germplasm.
"That's a total paradigm shift," he says. "This shows the value of thinking globally—trying to help your neighbors may in turn help you some day."
Natural gene selection can produce orange corn rich in provitamin A for Africa, U.S.
Global Partners in Research Combat Malnutrition
By Jennifer Stewart - Published May 18, 2015
Thanda Dhliwayo, a HarvestPlus plant breeder who works at CIMMYT, focuses on raising the provitamin A content of orange corn and developing drought-resistant varieties. (Photo by Jennifer Stewart)
On a breezy day just outside of Texcoco, Mexico, passersby can hear the rustle of food crops growing in the research plots surrounding the International Maize and Wheat Improvement Center, or CIMMYT.
Pulling back the husks on some of the corn plants reveals bright orange kernels—evidence of a long-standing collaboration between CIMMYT and Purdue
Agriculture. Orange corn, rich in provitamin A, is part of a HarvestPlus-funded project led by Purdue Agronomy
Professor Torbert Rocheford. The goal: To get provitamin A into the diets of
severely deficient populations, starting in Zambia.
Rocheford says the task would be impossible without his international partners. Indiana weather patterns, disease pressures and soil types don't lend
themselves to testing plants adapted to very different climates. "For example, corn adapted to Indiana is generally not going to have the kind of disease
resistance needed for Zambia."
Enter CIMMYT. Rocheford, with collaborators at Cornell and Michigan State universities working on a complementary National Science Foundation-sponsored project, identify natural forms of the target genes that will efficiently increase
orange color, provitamin A and total carotenoids. They share the results with CIMMYT, where researchers take the genetic information and put it into corn
ideally suited for growth in Zambia.
Relationships like this one have a variety of benefits, says Purdue's Jess Lowenberg-DeBoer, associate dean and director of International Programs in
"International collaborations enhance Purdue's research in several ways, including partnerships with cutting-edge researchers located outside the U.S. Our
research benefits from their skills and insights," Lowenberg-DeBoer says. "Sometimes these partnerships also give us access to scientific equipment and
infrastructure that we do not have at Purdue, and field research opportunities to test theories or hypotheses in a very different environment from what we
have in the U.S."
Corn to Conquer Climate Change
Orange corn isn't Purdue Agriculture's only work with CIMMYT. The two have partnered on a handful of other studies, including a project called Heat
Tolerant Maize for Asia (HTMA), led by Mitch Tuinstra, a Purdue professor of plant breeding.
Like Rocheford, Tuinstra needs access to the right maize varieties and growing conditions. His lab is working to identify the genes and traits for
heat-stress tolerance. The research team partners with CIMMYT on access to germplasm and testing environments. HTMA is tested in field plots at CIMMYT's
sister institution, the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), in Andhra Pradesh, India.
HTMA is a Global Development Alliance project funded by the U.S. Agency for International Development with matching funds from Purdue and public- and
private-sector maize breeding programs in India, Pakistan, Bangladesh and Nepal.
The project is vital as researchers race to understand how crops react to climate change. "We know almost nothing about crop adaptation to high-temperature
stress, and climate change is a big concern in Southeast Asia," Tuinstra says. "This presents serious challenges for the ability to produce enough food."
Purdue Agriculture works with public and private institutions, foundations and companies worldwide, including the Gates Foundation, the Tropical
Agricultural Research and Higher Education Center in Costa Rica, and Kabul University in Afghanistan.
The results of those partnerships not only improve lives elsewhere, but in the U.S., too, Lowenberg-DeBoer says.
"Any strategy that results in new knowledge and better understanding of the world around us benefits everyone," he says. "Sometimes those benefits are in
Indiana. In other cases, the benefits are elsewhere in the U.S. or in other countries. Even the research benefits in other countries often have spinoffs
for Indiana citizens."
Orange Corn Lends an Ear to America
If Rocheford has his way, people all over Africa, the U.S. and beyond will one day hear the rustle of orange corn dancing in the breeze. HarvestPlus
already has taken the crop to Zambia and Zimbabwe and is beginning a program in Ethiopia. The development of orange corn hybrids for the U.S. has started.
While Americans don't typically lack provitamin A, Rocheford says orange corn has high total carotenoids, a type of antioxidant, which could be good for
"The U.S. population doesn't really need any more vitamin A," Rocheford says. "But we may be deficient in the carotenoids lutein and zeaxanthin, which are
good for eye health. It's still unclear whether the increasing rates of macular degeneration are due to lower levels of lutein and zeaxanthin in the diet,
but the macular is full of them. It would be good to have more carotenoids in our diet."