Thousands of years of Indigenous farming traditions and myths have played a critical role in the survival of cassava, a vital food source for nearly a billion people worldwide, according to a new study. Despite being a clonal crop, meaning it is grown from stem cuttings rather than seeds, the latest findings reveal that cassava has maintained an unexpectedly high level of genetic diversity.
The research, conducted by a team from the University of Warwick, the Smithsonian Institution, and Embrapa (Brazil’s agricultural research agency), sheds light on how cultural practices have shaped the evolution of cassava. Their findings, published in Science, suggest that Indigenous farmers have actively preserved and enhanced cassava’s genetic diversity, ensuring the crop’s resilience against disease, drought, and poor soil conditions.
A Mysterious Level of Diversity
Cassava, also known as yuca or manioc, is primarily grown through clonal propagation, meaning farmers cut stems from an existing plant to grow new ones. Theoretically, this should result in low genetic diversity, making the crop more vulnerable to threats like pests and disease.
However, when researchers analyzed the genomes of more than 500 cassava plants—ranging from modern varieties to herbarium and ancient archaeological specimens—they found something surprising: cassava has even more genetic diversity than its wild relatives.
Exploring this mysterious level of diversity further, the researchers turned to Indigenous farming practices as a possible solution.
“We wondered if this practice of cloning stem cuttings would keep diversity low since reproducing by seed is a way of reshuffling the genetic deck and folding in new variation,” Dr. Logan Kistler from the Smithsonian Institution, the study’s first author, said in a recent statement. “We saw the total opposite: cassava has even more diversity than its wild relatives because of how people have prioritized and maintained diverse varieties.”
The Caterpillar God and Cassava
To uncover the roots of cassava’s diversity, the research team spoke with Indigenous farmers in Brazil, who described generations-old cultural practices that subtly but powerfully influenced the crop’s evolution.
One of the most striking examples is the story of Kukurro, a caterpillar god revered by some Indigenous communities. Farmers honor Kukurro by decorating their farming tools and creating special “Kukurro houses,” where they plant nearby cassava stems. This encourages sexual reproduction through seeds rather than cloning alone, introducing new genetic variation into the crop.
“Stories and myths linked with crops are a strong part of Indigenous cultures,” said Dr. Fábio de Oliveira Freitas, an Embrapa researcher involved in the study. “This kind of work shows how some myths can impact crop evolution, why it is so important to support those people and how much we still have to learn.”
Beyond mythology, cassava diversity has also been shaped by the movement of people and plants. Indigenous farmers in different regions trade and exchange cassava cuttings, preventing isolated genetic pockets and promoting widespread genetic mixing. In some cultures, newlywed brides bring cassava cuttings to their husbands’ villages as part of marriage customs, ensuring that diverse cassava varieties continue to spread.
Using Cassava as an Example for Global Food Security
The findings highlight the critical role Indigenous knowledge plays in maintaining biodiversity and food security, particularly in challenging environments.
“This study really shows the importance of small-scale Indigenous farming to our global food security,” said senior author Professor Robin Allaby from the University of Warwick. “Understanding these cultural biodiversity practices could help inform future breeding strategies and conservation efforts.”
In a world facing increasing climate challenges, these age-old traditions, like those used to help the cassava plant, may hold key insights for ensuring the resilience of other vital crops. Scientists and policymakers can work toward a more sustainable and secure food future by recognizing and valuing Indigenous agricultural wisdom.
Kenna Hughes-Castleberry is the Science Communicator at JILA (a world-leading physics research institute) and a science writer at The Debrief. Follow and connect with her on BlueSky or contact her via email at kenna@thedebrief.org