Africa must protect its agricultural biodiversity to build a food-secure future, writes Joyce Maru, Africa director at the International Potato Center.

[NAIROBI] Sweet potato has become a staple in many diets, but what about taro, anchote and ensete? While not currently global commodity crops, these locally adapted roots and tubers can greatly contribute to Africa’s food system transformation and future food security.

Resilient and nutritious crops such as these are part of Africa’s rich agricultural biodiversity. And they are increasingly important in the face of the climatic shocks that are affecting yields of more vulnerable cereals and vegetables.

Climate change is expected to reduce wheat yields across Africa by 15 per cent by 2050, while maize is also experiencing the impact of droughts, floods and crop pests. On the other hand, the hardy root crop cassava may benefit from the same climatic shifts.

Sustainably intensifying and diversifying Africa’s farming systems by integrating climate-resilient, nutritious crops such as roots and tubers into traditional maize-based systems is an excellent way of improving future food, nutrition and income security.

However, pests, diseases and climate vulnerabilities can still stand in the way of productivity. So we need to breed new, improved varieties to overcome these challenges in order to meet growing demand. This can take scientists several years and requires access to genetic diversity.

Investing in genebanks

A starting point would be ramping up efforts to explore, collect and conserve the genetic diversity of these indigenous and locally adapted crops in genebanks to safeguard potentially beneficial genetic traits and guarantee a pipeline of improved crops.

This diversity, only to be found within natural ecosystems, is also threatened by the challenges of climate change and other threats.

Developing a back-up collection of Africa’s most important and indigenous crops, though, is no mean feat, especially given that root and tuber crops are among the most difficult to store in the long-term.

While grain seeds can be stored for decades if not centuries, roots and tubers are conventionally stored in test tubes, or in vitro, and need to be regenerated every one to two years.

Even more resource-intensive is the conservation of this crop diversity in the field, where the risks and challenges of long-term conservation are more complex.

Effectively protecting agricultural biodiversity requires investment, technical expertise and constant maintenance – and Africa urgently needs support to develop this capacity.

‘Opportunity crops’

A growing number of initiatives are seeking to leverage the benefits of Africa’s indigenous, locally-adapted crops to boost harvests and food security and ensure food systems adapt to the impacts of climate change.

The Vision for Adapted Crops and Soils initiative, for example, is an effort led by the US, African Union and UN Food and Agriculture Organization to identify so-called “opportunity crops”, which have traditionally suffered from a lack of investment, to prioritise for improvement.

Among these opportunity crops are yams, sweet potato and taro, with some wild varieties offering significantly higher levels of key nutrients than their modern counterparts.

But even crops like taro and the drought-resilient ensete face challenges like taro leaf blight and enset bacterial wilt, both of which can result in losses of 70 to 100 per cent.

Genebanks have been instrumental in allowing crop scientists around the world to breed improved varieties of root and tuber crops.

One example is the CIP-Matilde potato, released in 2021, which was bred using crop wild relatives to be resistant to late blight, the most economically damaging potato disease in the world.

To overcome the challenges of long-term conservation of root and tuber crops, the use of cryopreservation – in which shoot tips are stored in liquid nitrogen – has been efficiently used at the International Potato Center’s genebank for potato, sweet potato and the lesser-known ulluco.

This technology provides a lifeline for the long-term conservation of these clonal crops to eliminate the need for regular regeneration.

The technique has been widely recognised by genebanks globally as the best alternative for efficient long-term conservation.

Building networks

In Latin America, the International Potato Center has developed a network involving 14 countries to improve their capabilities in cryopreserving the diversity of genebanks.

Such regional and international cooperation offers a model for Africa to benefit not only from the continent’s genetic resources but also from those elsewhere.

Although most African countries have national genebanks, many struggle with adequate staffing, infrastructure and budget, resulting in limited crop genetic collections.

Although some have some in vitro capacity, none of them currently have the infrastructure needed for cryopreservation.

A network of fully resourced genebanks, such as that implemented in Latin America, could ensure future generations continue to benefit from Africa’s agricultural biodiversity.

Africa also needs to strengthen its institutional capacity to support evidence-based policies at national and regional levels.

Investing in the collection and conservation of crop genetic resources is vital to ensure agriculture keeps pace with the growing pressures of climate change, pests and diseases – and to preserve Africa’s rich biodiversity for generations to come.

This piece was produced by SciDev.Net’s Sub-Saharan Africa English desk.