This post is written by Willy Pradel and Marcel Gatto of the International Potato Center (CIP).

Climate change and population growth are increasing concerns for global food security. Greenhouse gases in the atmosphere have reached record high levels and the world is currently on track to overshoot the targets of the Paris Agreement, heightening the importance of developing technologies to help farmers adapt to climate change. This is especially urgent for the poorest and most vulnerable farmers, who already struggle to produce enough food.

At the same time, we currently observe downward trends in varietal diversity in all major food crops in Asia and Africa. This means that traditional landraces are spatially displaced while so-called mega varieties increasingly dominate agricultural systems. As climate change impacts continue to affect agriculture, these trends have significant (and potentially worrying) implications for ensuring future yields and food system resilience around the world.

There is an urgent need for crop varieties and technologies that help smallholder farmers adapt to climate change.

Why root and tuber crops?

More than 300 million people living below the poverty line in developing countries depend on root, tuber and banana (RTB) crops for food and income, particularly in Africa, Asia and the Americas, and they are especially important for women, who frequently are responsible for marketing RTB crops.

These crops — which include banana, cassava, potato, sweetpotato and yam — have immense potential for reducing hunger and malnutrition and helping smallholder farmers adapt to climate change by reducing the dependency on grains. A major advantage lies in their resilience and ability to produce food with more vitamins, minerals and complex carbohydrates more quickly than many other crops. Their importance to food security in developing countries will only increase in the coming decades as the continent undergoes rapid urbanization and population growth. To improve farmers’ capacities to produce more nutritious food in a climate-changing world, CGIAR and its many partners are undertaking groundbreaking research to improve RTB crops, seed systems, pest and disease management and postharvest innovations.

Climate-smart breeding

With improved varieties needed urgently, scientists are raising the bar for breeding a next generation of RTB crops that are more climate-resilient, nutritious and desirable to local consumers.

CIP and partners have promoted an accelerated breeding scheme that cuts the time it takes to develop and release a new variety from eight years to four. In Mozambique, this approach led to the release of 15 pro-vitamin A rich, drought tolerant orange-fleshed sweetpotato varieties in 2011 and an additional four varieties in 2016. Those climate-resilient varieties now constitute about one-third of the sweetpotatoes grown in Mozambique, a country where extreme weather events frequently destroy crops. In Malawi, accelerated breeding and dissemination efforts also led to the widespread uptake of nutritious orange-fleshed sweetpotato varieties.

Breeders have likewise developed potato varieties tolerant to drought, heat and salinity and resistant to late blight, which were introduced in China and currently cover nearly 1,250,000 hectares. These varieties have tremendously contributed to economic welfare and poverty reduction, as clearly demonstrated in the case of Cooperation 88 in China. More recently developed climate change-resilient potatoes include the drought-, heat- and soil salinity-tolerant varieties released in Central Asia (Uzbekistan and Tajikistan) and Bangladesh. In India, climate-smart potato varieties are available and provide a certain degree of resistance against climatic stressors, especially early maturity and drought tolerance; however, at the state-level, mismatches are often observed between potato traits and climate projections, underpinning the need for increased investment in breeding and dissemination strategies.

Climate-smart seed systems

As new varieties are released, managing seed systems is crucial for ensuring that farmers adopt them and maintain quality planting material in the face of increasing incidences of drought that especially affect perishable planting material for next season as dry periods prolong in sub-Saharan Africa. Also, droughts increase the pressure of aphids that are vectors of viruses that reduce the quality of the plant material.

CIP researchers are promoting a practice that allows farmers to produce their own vines in time for the planting season. Known as Triple S — storage in sand and sprouting — it consists of storing sweetpotato roots in dry sand following the harvest, planting them in seedbeds six to eight weeks before the rainy season and watering them to produce enough vines to plant when the rains begin. Also, to avoid aphid attack in high virus pressure areas, the use of net tunnels is being promoted.

Providing the optimal regulatory framework for managing seed systems will be crucial, not only because RTB crops are biologically distinct from other crops, but also because of the adverse effects of climate change. Policy options exist, such as recognition of farmer-saved seed as seed class, truthful labeling, investment in early generation seed production facilities, etc., as demonstrated in the case of cassava and potato in Vietnam.

RTBs today and tomorrow

There have been significant increases in the production of RTB crops since the 1960s, particularly of cassava in Africa and potato in Asia. Changing climates, however, poses a major challenge to rising production.

A recent study on modeling future agricultural production trends based on different climate change and socioeconomic pathways, conducted by different CGIAR centers, found that by 2050, climate change and water availability will be key factors for crop productivity: whereas banana and potato are sensitive to water stress, cassava, yam and sweet potato are drought tolerant. Agroecological conditions and poverty will cause the consumption of RTBs to increase, especially in Africa, indicating their growing importance for food security threatened by climate change. While potato stands out as the crop most affected by changing preferences, especially in China, the banana will exhibit the highest growth in supply and demand across all regions. RTB crops have great potential for reducing malnutrition and poverty through 2050, as long as they are on the receiving end of appropriately targeted investments.

Moving ahead

As climate change deepens food insecurity through factors such as yield losses and limited access to affordable planting materials, inflexible seed dissemination strategies and unadapted regulatory frameworks, the need for climate-smart RTB technologies will be greater than ever. Funding for developing climate-smart varieties, seed systems, post-harvest technologies and regulatory frameworks will be crucial for a food- and nutrition-secure and climate-affected future for smallholder farmers around the globe.