Genetically Modified Cassava

by Sophie Broach:

New technologies have complicated the challenge of feeding Africa.

In Umudike, Nigeria, the rows of leafy green cassava plants growing at a confined field trial site are the result of millions of dollars in funding, years of research, and a collaboration that spans continents. For some, these genetically modified (GM) plants promise an agricultural revolution that could eliminate hunger and malnutrition in sub-Saharan Africa. For others, they pose a grave threat to environmental integrity, human health, and traditional farming techniques.

“Cassava is the most important food crop in sub-Saharan Africa,” declared Dr. Claude Fauquet of the Danforth Plant Science Center in St. Louis, Missouri. Where other crops fail, this sweet potato-like vegetable thrives. It resists drought, grows in poor soil, repels herbivores with its cyanide-laden leaves, and requires minimal labor to plant. Cassava can be left in the ground for up to three years and removed whenever needed. Not surprisingly, at least 100 countries worldwide count on cassava as a staple food.

However, the 250 million people in sub-Saharan Africa who rely on the plant as their major source of calories are prone to malnutrition. The starchy vegetable has the lowest protein-to-energy ratio of any staple crop and lacks adequate levels of vitamins A and E, iron, and zinc. Some varieties do contain in abundance compounds that can cause cyanide poisoning when eaten. Cassava’s susceptibility to devastating viral diseases also jeopardizes its status as a food security crop. Recently, the cassava mosaic virus and brown streak disease have ravaged harvests in East and Central Africa, reducing yields by as much as 50 million tons each year.


Two teams at the Danforth Center have set out to fix the flaws in this exceptionally important staple crop by genetically engineering the perfect cassava. One group, Biocassava Plus, or BC Plus, aims to raise cassava’s levels of iron, protein, and vitamin A to provide the complete minimum daily dietary requirements for these nutrients in a cassava-based diet. Martin Fregene, the director of BC Plus, explained that this can only be accomplished through genetic engineering: “You don’t have a natural genetic variability for iron or protein in cassava. You don’t have it there. You’re stuck.” BC Plus draws the genes for this purpose from various plants, algae, and microbes.

Two BC Plus cassava roots fortified with beta carotene (left) next to a wild type of cassava lacking in beta carotene. (Courtesy Danforth Plant Science Center)

The second team, Virus Resistant Cassava for Africa, or VIRCA, has the urgent task of developing cassava plants resistant to cassava mosaic virus and brown streak disease by using genes from the viruses themselves. Fauquet, Danforth’s VIRCA director, predicted terrible instability for Nigeria’s population of 155 million should brown streak disease spread to this very cassava-dependent area, but he hopes the virus resistant cassava developed by VIRCA could mitigate the effects of such a disaster.


Many groups oppose the introduction of these seemingly miraculous types of GM cassava. When asked about the health consequences of consuming GM foods, Gareth Jones of Biosafety Africa, explained simply, “Nobody really knows! This is the problem… No long term studies have been done.”

Critics also worry about the enduring consequences of introducing genetically engineered plants into natural ecosystems, fearing they could eliminate biodiversity in areas beyond their intended use by outnumbering and surviving over their disease-prone counterparts. “The deliberate release of GM into the environment… can lead to irreversible damage to ecosystems,” explained Glen Tyler of Greenpeace International’s agricultural campaign. “Once one of these crops is out of the bag, it’s hard to put it back in the bag, so to speak.”

“When new [GM] varieties are introduced, they tend to be planted in mass,” Jones said. Indeed, VIRCA has developed two cassava cultivars for each country and hopes that soon these types will be as widely adopted as possible. Although, as Fauquet pointed out, “Cassava is not a single plant or a single variety for all of Africa… you have hundreds of different ethnic groups that prefer different plants because they have different habits.” Fauquet does not worry about this wealth of biodiversity being wiped out but, instead, frets over how to persuade African farmers to adopt the GM cassava on a large scale.

The close relationships between development organizations and biotech companies have been another cause for criticism by anti-GM groups. Monsanto, the agricultural biotechnology corporation responsible for the majority of the world’s GM seeds, provided a $50 million gift to its neighbor in St. Louis, the Danforth Center, when it was founded and later donated $7.5 million to VIRCA. The Bill & Melinda Gates Foundation, which employs multiple staff members who previously worked at biotech companies, gave $12 million to BC Plus and recently pledged an additional $8.3 million grant to support later stages of the project.

The sources of funding for VIRCA and BC Plus have caused some to re-examine their underlying purposes. Are these ostensibly charitable development projects actually attempts by corporate First World interests to take over African agricultural systems? Fauquet rebutted that his work is “for pure humanitarian purposes.” He asserted that Monsanto “is only really helping us financially and providing technologies or information, but they… are not driving our plans.”

Even if no opportunities for abuse seem immediately apparent, however, some worry they may emerge in the long run. Jones explained, “Most of the farmers in Africa use and re-use their own seed. With GM seeds you have the issue of patent protection. The biotech companies say they will give their seeds out royalty free, but for how long? Once all other seeds in a region have been replaced with GM varieties, what will be the farmers’ choice?”

Tyler posited the idea that although uptake of GM cassava in African countries might never directly enrich biotech companies, gaining acceptance for GM goods as

a humanitarian technology may make the climate around selling such products less controversial worldwide. Fears about the environmental and health risks of GM foods prevail in many countries, severely limiting markets for biotech companies. Some European countries, including France, have even banned imports of Monsanto’s GM maize.

When questioned about environmental opposition to the VIRCA program, Fauquet laughed: “I think [they] are looking at the wrong problem. We have huge problems on this planet,” like malnutrition, which contributes to the deaths of roughly 5 million children each year.


Opponents of VIRCA and BC Plus have argued that pouring millions of dollars into complicated biotech projects diverts money and energy from simpler development methods that have been proven to work. Tyler pointed to genetic engineering programs with underwhelming track records such as the Rockefeller Foundation’s Golden Rice

Project, which strives to save millions from death and blindness with GM biofortified rice, but so far has little to show for its 20 years in development and over $100 million in funding.

Meanwhile, a number of programs that are simpler and less expensive have had greater success than their high-tech counterparts. Unleashing the Power of Cassava in Africa, for example, has succeeded in doubling cassava yields in the Ido community in Nigeria by simply educating farmers about proper land preparation, weeding, stem handling and transportation, and use of fertilizer, while disseminating improved, non-GM cassava varieties. “All we need is to educate the farmers more and let them receive… new materials that are in the system that they have not had access to,” explained Richardson Okechukwu, the organization’s deputy project manager in Nigeria.

Critics like Tyler argue that we can eliminate world hunger with existing technology. He sees this problem as rooted in a lack of support for small-scale farmers and poor policy and distribution rather than inadequate supply. Jones likewise asserted, “The removal of massive farming subsidies in the U.S. and Europe and the altering of the global trade system would arguably do far more to alleviate human suffering in the Global South than any single technological ‘silver bullet.’ ”

Despite all the controversy surrounding the genetic engineering of the cassava plant, Fregene and Fauquet remain confident that these technologies will soon be the key to feeding a rapidly growing planet. Fregene predicted ominously, “Even if you plowed all the game parks in East Africa, plowed all the forests in northern Europe… you would still run out of land to feed an ever growing human population.” “GM tech is here to stay… We cannot feed tomorrow’s population with the technology of yesterday,” he said. Fauquet put it less bleakly “I am absolutely convinced we can feed 10 billion people. This is not a problem. The question is: Are we going to do what is necessary to do that?” Both development organizations and environmental groups agree that we must do what is necessary to solve Africa’s food crisis and foster independence from foreign aid—they just disagree on how.

Sophie Broach ’13 is a History major in Pierson College. Contact her at

3 Responses to “Genetically Modified Cassava”

  1. Nice article, but a propos your final “ominous” quote from Fregene, I wonder whether you’re aware of Christoph Mueller’s work on how little land is needed to grow enough staples to feed the world in 2050 and“>this one.

    And then there’s another point, that many of the small farmers who grow and eat cassava actually like a bit of mosaic in their leaves, because it makes them easier to cook and eat and thus helps them get the micronutrients they need.