Strengthening Local Capacity to Breed Better Sweetpotatoes

Maria Andrade, a CIP sweetpotato breeder based in Maputo, Mozambique, can hardly believe the progress that has been made on improving that important crop for African farmers in recent years. “A decade ago, there were very few (sweetpotato) breeding programs in Africa; they mostly depended on the introduction of material from other countries or regions to do adaptive trials, and that material often did not adapt to local conditions,” she explains.

Andrade is one of four CIP scientists who have spearheaded a transformation of sweetpotato breeding in sub-Saharan Africa over the past five years. They are working to expand and accelerate the development of varieties that are adapted to local conditions in order to improve food security, health and incomes.

CIP is strengthening the sweetpotato breeding capacity of national agricultural research systems (NARS) across the continent, in close coordination with the Alliance for a Green Revolution in Africa (AGRA), as part of the Sweetpotato Action for Security and Health in Africa (SASHA) project, funded by the Bill and Melinda Gates Foundation. CIP has provided the latest technology and helped breeders adopt new tools and methods through training and knowledge sharing. This has created a breeders’ community of practice that has produced impressive results: 46 new sweetpotato varieties released in the region since 2009, 37 of which are orange-fleshed varieties rich in beta-carotene (provitamin A) that can greatly improve the health of young children. And because it takes years to develop and release a new variety, the initiative’s output has barely begun.

“There is no comparison with the way things were 10 years ago, because we are now in this network,” Andrade says. “We speak the same language and we use a common protocol with common procedures. Through this interaction, we are really making progress.”

Support Platforms at the Core of Decentralization

Wolfgang Grüneberg, who coordinates CIP’s efforts to improve sweetpotato breeding, explains that a decade ago, CIP emphasized a centralized breeding approach in which new varieties were developed in Peru and shipped to other regions for evaluation and possible adoption. Now CIP prioritizes a decentralized approach, which focuses on strengthening national breeding programs and taking advantage of the genetic diversity of local sweetpotato populations.

To achieve this, CIP has established support platforms in sub-Saharan Africa (SSA) and Asia that are strengthening the breeding programs of NARS in those regions. These include three sub-regional platforms in SSA that support local breeding efforts: an East Africa platform based in Uganda, a Southern Africa platform based in Mozambique and a West Africa platform based in Ghana. Because of the decentralized breeding approach’s success in Africa, an Asian platform was recently established to work with NARS in India, Bangladesh and Indonesia. CIP’s work in South America and Haiti remains centralized, with varieties being developed at CIP headquarters in Lima, Peru, with the exception of a NARS breeding program in Cuba.

Over the past five years, each African support platform has organized one or two regional workshops per year, and CIP has brought Africa’s top sweetpotato breeders together for annual meetings. CIP scientists also arrange capacity building for smaller groups in specific countries as needed. CIP has developed and provided training in protocols and software for data management, analysis and sharing; the use of molecular markers for parental breeding; and an accelerated breeding scheme to reduce the time it takes from the initial cross to having a variety ready for release.

“We put an emphasis on sharing knowledge, and it is trickling down. Each of the breeders that participates in the workshops usually has one or two technicians working with them, as well colleagues in their institution who work on other crops,” Grüneberg explains. “There are now more sweetpotato breeding programs in Africa, more breeders with more knowledge of African sweetpotato breeding material and, most importantly, there are many more sweetpotato crosses being made in Africa for Africa.”

Robert Mwanga, who heads the East Africa support platform, notes that decentralized breeding is essential because each region is composed of different environments, making it difficult to develop a variety that will thrive in all parts of a country, let alone several countries. While all the platforms promote the development of resilient sweetpotato varieties with high nutrient content and dry matter, each one also focuses on a specific trait of importance for their region. In the case of East Africa, the priority trait is virus resistance, whereas in Southern Africa, it’s drought tolerance, and in West Africa, it’s low sugar content.

“The three platforms have different major focuses, but we all come together for a single training with the same tools. This way we minimize the duplication of efforts and maximize the use of resources,” says Mwanga.

According to Ted Carey, who manages the West Africa breeding platform, in close collaboration with Ghana’s Crops Research Institute (CRI), sweetpotato was a seriously neglected crop in that region prior to SASHA. Five years ago CRI was simply introducing and releasing varieties today it has a modern breeding program that makes crosses, analyzes progeny using the latest approaches, and develops new varieties.

“We have two major objectives – population improvement and participatory variety selection for release,” says Carey. “All of our activities are thoroughly collaborative, from the beginning to the release.”

Accelerated breeding

CIP’s capacity building efforts are complimented by AGRA’s support for graduate students and post-docs in sweetpotato breeding. CIP has provided equipment for procedures such as near infrared reflectance spectroscopy and software such as CloneSelector, and has trained African scientists in the use of that technology, all of which is speeding up the breeding process.

“CIP wants to revolutionize conventional sweetpotato breeding,” observes Mwanga.

One of CIP’s most revolutionary contributions has been the accelerated breeding scheme. Traditionally sweetpotato breeding programs have taken eight years to develop a new variety, this new technique has resulted in the development of various new varieties by different breeding programs in only four years. Accelerated breeding takes advantage of the fact that in breeding clonally propagated crops, each true seed plant is a potential variety. After each plant from a true seed is rapidly multiplied, the vine cuttings are planted in different environments for simultaneous field tests. The key to accelerated breeding is the early testing of genotypes over multiple locations, in contrast to the traditional approach of multiple cycles of evaluation at one location before going to multi-location testing as a final step in the selection process. Sweetpotato breeders can now identify viable candidates faster than they used to.

African scientists using this accelerated breeding scheme have adopted the moniker ‘speedbreeders,’ and their work is resulting in the development and release of more resilient and healthy sweetpotato varieties than African farmers have ever had access to before. Those varieties will play a vital role in efforts to improve diets and livelihoods across the continent, and to feed a growing population while adapting to a changing climate.

CIP is strengthening the sweetpotato breeding capacity of national agricultural research systems (NARS) across the continent
Robert Mwanga discusses the platform concept near an OFSP crossing block in Rwanda

“Our community of practice is quite coherent, and the result is that more varieties are being released and they are being developed much more quickly than in the past,” Mwanga observes. “I think that we will accomplish a lot in the coming years.”

For further information, read: Grüneberg W.J., Mwanga R., Andrade M. and Espinoza J., 2009. Selection methods Part 5: Breeding clonally propagated crops. In: S. Ceccarelli, E.P. Guimarães, E. Weltzien (eds) Plant breeding and Farmer Participation, 275 – 322. FAO, Rome.