Sweet potato breeding efforts at the International Potato Center in Maputo, Mozambique. Photo by: Sara Jerving / Devex

MAPUTO, Mozambique — Maria Andrade knelt over and picked up the vine of a sweet potato plant growing in her favorite greenhouse in the International Potato Center’s research and development lab in Maputo, Mozambique.  

“The leaves are beautiful, aren’t they?” she asked.  

Andrade is principal scientist at the International Potato Center, a CGIAR research center, and a leading orange-fleshed sweet potato breeder in Africa.

“If I could see every house giving orange-fleshed sweet potatoes to their children, helping to solve vitamin deficiencies, I will die very happy, because I served my purpose.”

— Maria Andrade, principal scientist, International Potato Center

The greenhouse is full of drought-resistant strains of sweet potatoes her team bred in collaboration with Mozambique’s government. They’ve sent these varieties across Africa to help farmers deal with the climate change-fueled droughts that have increased in frequency in recent years, according to Andrade.

Small signs stuck in the mud under the plants read names including Alisha, Esther, Caelan, and Erica. Andrade names her varieties after women and girls that promote the spread of orange-fleshed sweet potatoes across Africa. Only one man has made the cut.

“Other men get jealous and say I should name my breeds after them. But I tell them: ‘You are not worthy!’” she said, laughing.

You could call Andrade a sweet potato fanatic. She always wears orange — orange shawls, orange hats, orange dresses. She’s built her life around the promotion of orange-fleshed sweet potatoes in Africa, earning her the nickname “Senhora Polpa Alaranjada,” or “orange flesh lady” in Portuguese.

In 2016, she was co-recipient of the World Food Prize for her contributions to global nutrition for her breeding programs. Two other members of her team, Jan Low of the U.S. and Robert Mwanga of Uganda, also won the prize.

The three were honored for “developing the single most successful example of micronutrient and vitamin biofortification — the orange-fleshed sweet potato.” Andrade and Mwanga have bred orange-fleshed sweet potatoes rich in beta carotene and Low developed nutrition studies and programs to encourage people across the African continent to produce and consume this biofortified crop.

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The breeding of orange-fleshed sweet potatoes has been particularly successful because there are a lot of varieties of the crop that can be used in cross-breeding. The International Potato Center has sped up the breeding process — producing new varieties in four years rather than eight — which has made the new varieties available faster in more countries than other biofortified crops, Low explained.

The team’s enthusiasm around this crop is rooted in the conviction that a transition from the commonly consumed white-fleshed sweet potato to the orange-fleshed sweet potato could drastically reduce deficiencies in vitamin A across Africa.

A 2005 study conducted in South Africa monitored school children that consumed orange-fleshed sweet potatoes for 53 days, compared to those who ate white-fleshed sweet potatoes. Those who ate orange-fleshed sweet potatoes had significant improvements in the vitamin A levels stored in their livers over those who didn’t, increasing from 78% to 87%.

“All sweet potatoes, both white and orange, are very nutritious — they have vitamin B and vitamin C. But the orange-fleshed one has one more thing, which is beta carotene,” Andrade said. “When people consume beta carotene, the body changes it to vitamin A.”

Vitamin A deficiency can weaken immune systems, increase mortality, and limit growth. It is also the leading cause of preventable childhood blindness.

Globally, about 250 million preschool-aged children are vitamin A deficient and an estimated 250,000 to 500,000 of these children become blind every year, half of which die within a year of becoming blind. Vitamin A is especially an issue in Africa and Southeast Asia.

In addition to beta carotene, Andrade’s team is breeding varieties of sweet potatoes to increase iron levels.

Still, despite advances in breeding leading to sweet potatoes with higher levels of beta carotene, there are also the hurdles of getting the new varieties to the farmers’ fields and people’s plates.

Dr. Maria Andrade with a drought-resistant variety of sweet potato that she named after Melinda Gates. Photo by: Sara Jerving / Devex

Introduction in Mozambique  

Andrade, a native of Cape Verde, was recruited in 1996 to Mozambique to work for the Southern Africa Root Crop Research Network, led by the International Institute of Tropical Agriculture and International Potato Center, to focus on improving the yield of cassava and sweet potatoes, as well as pest and disease resistance. At the time, farmers in the country produced only white-fleshed sweet potatoes.

Andrade had just finished a doctorate at North Carolina State University, where her research focused on orange-fleshed sweet potatoes. In attempts to decrease high levels of vitamin A deficiency in Mozambique, in 1997, her team began to import orange-fleshed varieties high in beta carotene from countries including the United States and Peru. The plant is native to the Americas. They then began to test clones of the orange-fleshed sweet potatoes and released nine varieties in Mozambique.

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When flooding hit Mozambique in 2000, it wiped out sweet potato crops across the southern part of the country. In response, the International Potato Center team distributed orange-fleshed sweet potato vines to 121,000 families, accompanied by a marketing campaign to encourage its consumption.  

In 2005, a severe drought wiped out some varieties of sweet potatoes in Mozambique, which prompted the development of a national breeding program to focus on drought-tolerant varieties. In 2011, the first batch of 15 drought-tolerant varieties were released.

"Sweet potato is a smart agricultural crop,” said Tawanda Muzhingi, a Nairobi-based food scientist at the International Potato Center. “It doesn't need a lot of water, it doesn't need a lot of inputs, it has a short growing cycle, within three to four months you can have a harvest. In these areas that are prone to droughts, I think orange-flesh sweet potatoes can be a good security food crop.”

The work continues, with efforts to improve the levels of drought-tolerance by cross-breeding varieties of local drought-tolerant, white-fleshed sweet potatoes with imported orange-fleshed sweet potatoes.

Increasing iron and appealing to consumers

Through its breeding, the International Potato Center team has increased the levels of beta carotene by over 100%.

In addition to vitamin A, Andrade’s team is working to increase the iron content in sweet potatoes. Iron deficiency in children can impact their growth and development.

“Contrary to beans, sweet potatoes have very high levels of vitamin C, which can improve the iron intake. Also, the inhibitor of iron absorption, which exists in beans, does not exist in sweet potatoes,” Andrade explained.

The team bred a clone orange-fleshed sweet potato with high levels of iron. This is now part of a feeding trial in Malawi that is testing for bioavailability, which checks whether the body can actually absorb the iron. Results are expected in the next few months, Andrade said.

Some of the sweet potatoes they’ve bred are purple-fleshed, which is a source of anthocyanin, which has antioxidant effects.

But even with advances in nutritional content, breeders struggle with making sure the taste and texture meets consumption demands. The white-fleshed sweet potato, commonly consumed across the African continent, is much drier and less sweet than the orange-fleshed varieties popular in places like the U.S.

“For Africa, they want it drier because they use it as a staple, to function like bread for breakfast,” Andrade said.

As you increase levels of beta carotene, the dryness is reduced, she said. The key to breeding the orange-fleshed varieties is increasing the nutritional value, while also creating a variety that is dry enough.  

Drought-tolerant breeding efforts in Mozambique are linked with a network of breeding programs across the continent. In West Africa, the focus is on breeding for desired taste and texture, and in East and Central Africa, the focus is on breeding for disease and pest tolerance.  

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The Peru-based International Potato Center and its partners have developed and disseminated more than 130 orange-fleshed sweet potato varieties across Africa and Asia, reaching 5 million households. Beyond its breeding centers in Africa, a center is under construction in Bangladesh, which will coordinate the release of orange-flesh sweet potato varieties in parts of Asia, with a focus on Bangladesh and India.

Sweet potato consumption is not widespread in Bangladesh. The biggest challenges in this setting are convincing the government to prioritize sweet potato as a national crop because it is not seen as a commercial crop that could bring foreign currency from international trade. The crop is also bulky and perishable, which reduces its shelf-life, and sweet potatoes are considered a "poor man's crop," Muzhingi said.

But recently things have started to change, according to Simon Heck, program leader at the International Potato Center in Kenya. In Bangladesh, there's been an overreliance on rice that has resulted in nutritional deficiencies and oversupply, making it hard to produce profitably.

Because of this, the government of Bangladesh is prioritizing diversification away from rice. The sweet potato has been selected for support, which includes government funds for research and dissemination.

Some of the main rice producing areas have also been badly impacted by an increasing salinity of soil and water due to rising sea levels.

"There is great urgency in finding alternative crops that can tolerate higher levels of salinity — and sweet potato is very well adapted to that environment," Heck said.

Sweet potato breeding efforts at the International Potato Research center in Maputo, Mozambique. Photo by: Sara Jerving / Devex

Farmers’ access

While breeding efforts have been successful, there are still challenges in ensuring the sustainability of its consumption.

The latest batch of drought-resistant seeds from Andrade’s team will be released at the end of August. Adequate funding is necessary to encourage the widespread use of these new varieties, she said.

As part of the efforts to get new varieties to farmers, the International Potato Center led a six-year “Scaling Up Sweetpotato through Agriculture and Nutrition” project in South Asia and Africa, including Mozambique, with 20 partner organizations, that ended this year.

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Through the project, 2.3 million households with children under the age of 5 were provided with planting material to produce orange-fleshed sweet potatoes. Almost a quarter of these households started producing orange-fleshed sweet potatoes, according to the International Potato Center. Of these families, about 70% still produced orange-fleshed sweet potatoes a year after receiving planting materials.

The project’s ongoing work aims to reach at least 6.5 million consumers with orange-fleshed sweet potatoes over the next three years, focusing on Bangladesh, Ethiopia, Kenya, Nigeria, and Uganda.

One challenge is making sure that there are markets for orange-fleshed sweet potatoes. 

Farmers are faced with a dilemma when deciding what to grow, Muzhingi said. They can grow orange-fleshed sweet potatoes to improve their household’s nutrition, but then they often can’t sell their surplus because there is no market. Or they can grow a cash-crop, like sugar cane, which they can sell, he said. The key to leading farmers toward orange-fleshed sweet potatoes is creating commercial markets for farmers to sell their surplus.

In Kenya, for example, the International Potato Center worked with the supermarket chain Tuskys to develop a bread that substitutes half of the wheat flour for orange-fleshed sweet potato puree. This created a market for smallholder farmers to sell their surplus. In Mozambique, because of smaller markets and fewer processing companies, the success of these efforts have been limited.

Another challenge is the sustainability of programs working to promote the production and consumption of these crops.

One of the main programs in Mozambique, the U.S. Agency for International Development-funded “Viable Sweetpotato Technologies in Africa” Mozambique project, under the U.S. “Feed the Future” initiative, was working to get orange-fleshed sweet potatoes into the hands of farmers. The program promoted the consumption of orange-fleshed sweet potato varieties in communities in Mozambique through increasing access to planting material, nutrition education, and market development, with a focus on families with children under 5 and women of reproductive age. The program reached nearly 74,000 households.

The $12.3 million program was expected to run from 2014 through 2021. But late last year, project implementers were informed the project was cut because of funding shortages. It stopped operations in June.

According to a USAID official, the decision to shut down the program was because the agency "revisited strategic opportunities for future agricultural investments."

This move follows significant decreases in U.S. agricultural development assistance and emergency food aid to Mozambique in recent years. In fiscal year 2014, $21 million in agricultural development funding was allocated and in fiscal year 2018, $6.8 million was allocated, which is a 68% cut, according to U.S. government budget requests and Food for Peace fact sheets.

Mozambique was also removed, along with eight other countries, from the list of Feed the Future’s “focus” countries, which meant it was no longer a target for higher U.S. investments in agricultural development and market access programs.

These USAID cuts could affect the spread of orange-fleshed sweet potatoes in Mozambique, Andrade said, stunting efforts to grow markets and develop products. Other agencies have not yet stepped up to fill in this gap, she said.

“USAID has been our greatest support over the years and all off sudden, to remove the support — we felt unprepared for such change,” she said.

Despite these challenges, in Mozambique, about 31% of all sweet potatoes grown in Mozambique are now orange-fleshed, according to Andrade, which she considers a great success.

"We've had significant success in Mozambique,” Muzhingi said. “If you go to northern Mozambique, you find orange-fleshed sweet potato sold in the market, households growing them, government programs using them, and NGOs promoting them as an effective strategy for the alleviation of vitamin A deficiency.

“It’s no longer a [International Potato Center]-only initiative. It’s embedded in the government’s national strategies towards malnutrition.”

Other countries that have been particularly successful with adopting the orange-fleshed sweet potato include Rwanda and Kenya, he added.

“This is a mission. We call it a revolution,” Andrade said. “If I could see every house giving orange-fleshed sweet potatoes to their children, helping to solve vitamin deficiencies, I will die very happy, because I served my purpose.”

“I have a feeling that one day this will happen. But we still have a lot of work to do.”

Editor’s note: CARE facilitated Devex's travel and logistics for this reporting with support from the Bill & Melinda Gates Foundation. Devex maintains full editorial independence and control of the content.

About the author

  • Sara Jerving

    Sara Jerving is a global health reporter based in Nairobi. Her work has appeared in The Wall Street Journal, The New York Times, the Los Angeles Times, Vice News, and Bloomberg News, among others. Sara holds a master's degree from Columbia University Graduate School of Journalism where she was a Lorana Sullivan fellow. She was a finalist for the Livingston Award for Young Journalists in 2018, part of a Vice News Tonight on HBO team that received an Emmy nomination in 2018 and received the Philip Greer Memorial Award from Columbia University Graduate School of Journalism in 2014. She has reported from over a dozen countries.

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