Study Report: Assessing the crop diversity conserved in Article 15 collections for their importance to climate change adaptation

Julian Ramirez-Villegas, Kauê de Sousa, Hannes Gaisberger

Climate change represents one of the most pressing challenges of the moment, having profound impacts on ecosystems, economies, and human well-being1. Driven largely by human activities such as the burning of fossil fuels and deforestation, the Earth’s climate is changing much faster than previously thought2. Rising temperatures, changing precipitation patterns, and extreme weather events pose significant threats to global food security, which largely relies on crops as the main source of food for humans and animals3. The interactions between climate change and food security are complex, but a coherent global pattern of direct impacts on crop productivity is emerging, with negative consequences for food availability that puts the stability of whole food systems at risk4,5. Other threatening aspects for agriculture include the potential for deterioration in the nutritional quality of staple crops6, a loss of biodiversity7,8 and an increased incidence of pests and diseases9. In view of these challenges, the importance of agricultural plant diversity – referring to the variation among species, varieties, and individual plants – emerged as a critical factor for both adapting to and mitigating the impacts of climate change10,11.

More than half of the world’s calorie intake comes from three crops - wheat, rice, and maize - making our food supply system extremely vulnerable12,13. Furthermore, the promotion of high-yielding varieties in the 1960s-1980s, optimized for specific environmental conditions, led to an accelerated replacement of landraces and the destruction of the habitats of their wild relatives. This dramatic loss of genetic resources was recognized as “genetic erosion” 14, and recommendations were made to expand genetic variation between varieties of important staple crops. In addition, national and international programs have been launched to collect and preserve the genetic diversity of crops in genebanks. To support a global system for the conservation of agricultural plant diversity the Global Crop Diversity Trust (Crop Trust) was established. Its mission is to support genebank collections of unique and valuable plant genetic resources for food and agriculture and to make them available for use by farmers, plant breeders and other scientists. This mission is particularly relevant given that national food supply and production systems worldwide are highly interdependent in terms of plant genetic resources, with the average degree of dependence of countries on “foreign” crops being around 69%15.

Traditional breeding programmes have and are likely to continue to play a crucial role in improving the resilience and adaptation of crops to changing climatic conditions. The key for the success lies in the availability of genetically diverse landraces and crop wild relatives (CWR) containing the desired traits such as resistance to drought, heat or a specific pest or disease13,16. As the future climate in the tropics and subtropics is expected to quickly move outside the range of previous experience17, additional international movement of diverse and resilient germplasm will be necessary to help farmers, such as African smallholders, to adapt in time16. For example, it is estimated that these novel climate conditions, currently unrepresented in the respective country, are predicted to become widespread for 29 major crops in Sub-Saharan Africa18. Current bottlenecks preventing faster adaptation include inadequate protection of CWR and landraces in situ and ex situ as well as missing trait information13, insufficient funding to maintain key collections and their lack of integration into larger breeding programmes16, and disproportionally low research investment levels for crops better adapted to future climates in general19.

The studies cited provide further evidence that agricultural plant diversity can represent a major solution for adapting to the imminent threats of climate change through international collaboration in the conservation and use of crop genetic diversity such as the Multilateral System for access and benefit sharing of the International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA; https://www.fao.org/plant-treaty/en/).

In this study we assess the diversity of 10 target crops (rice, maize, wheat, potato, sweet potato, sorghum, common bean, chickpea, pigeon pea, cowpea) conserved in Article 15 collections of the ITPGRFA, for their importance in climate change adaptation. For each crop, the current climatic variability represented by the collection sites of the conserved genebank accessions was quantified and compared to the range of projected climatic conditions under different climate change scenarios in 2050 and 2070 in its main production area. Thus, the main objectives of this study were to:

• Analyse the changes in climate conditions using several climate scenarios (in 2050 and in 2070) in current production areas of the 10 selected crops represented in the Article 15 collections.
• Analyse the range and diversity of the climatic characteristics of the collection sites of the international collections of the 10 selected crops conserved in international genebanks, covering both cultivated and wild material.
• Conduct a gap analysis by comparing the outcomes of 1 and 2 above and assess the extent to which future climate conditions in key production areas are represented in the international collections of the 10 selected crops.
• Draw conclusions and recommend a set of actions for international genebanks and the Crop Trust to improve ex situ conservation and use of the conserved genetic resources of the 10 selected crops in the face of climate change.

The findings will contribute to the overall goal of enhancing the diversity and resilience of agricultural systems and achieving long-term food security.