Climate change and human activities are contributing to environmental deterioration and the loss of biodiversity globally. To avoid extinction, populations of different species will need to adapt to new local conditions or migrate to new suitable habitats. Among the organisms that will be most sensitive to climate change are domesticated species. This sensitivity is due to at least three factors: 1) the intensity of artificial selection during domestication tends to greatly reduce genetic diversity and as a result, most domesticated species have low genetic diversity, small population sizes, and a high accumulation of genomic load; 2) during domestication, traits of human interest are often selected for, while physiological traits are often controlled by the breeder; 3) the cultivated species are geographically limited and their potential migration to suitable sites depends on human management, including the deforestation of natural vegetation and the resulting intensification of global warming. In combination, these three factors limit the capacity of domesticated species to adapt to new climatic conditions. Given that our future food supply will depend heavily on domesticated species, it is imperative that we design alternative strategies for their management and conservation.

To mitigate the impact of climate change on domesticated species, it has been proposed that wild relatives or landraces – local varieties adapted to the environment – could be used to introduce useful genetic diversity into vulnerable populations. In theory, characteristics of interest can be introduced through adaptive introgression, a mechanism by which a fragment of DNA that confers a beneficial adaptation is introduced into the genome of another species through crosses and backcrosses. The development of genomic sequencing and complex statistical programs have made it possible to identify the genetic bases of beneficial adaptations and to identify the genetic variants that confer local adaptation to conditions found in climate change. Recently, machine learning algorithms have been developed which allow the construction of models that describe the change in the frequencies of adaptive alleles in regional populations. By projecting these models into the future, and comparing them with current models, it is possible to identify geographic regions where populations will need to respond to selection and have a resulting change in allele frequency to adapt to new climatic conditions. In theory, those populations that must respond to selection pressures will be more vulnerable to climate change than populations that will remain stable over time. This valuable information can be used to prioritize populations for conservation, identify populations that could contribute useful genetic diversity to vulnerable populations, and design the mechanisms of adaptive gene flow between vulnerable and resilient populations.

The species of interest for our Network, the Lima bean, has increased in global relevance in the last decade. This is partially the result of a growing concern for food security as climate change has begun to pose challenges for grain legume production. It is also because Lima beans have a greater range of ecological adaptations than that observed in the common bean (P. vulgaris). This suggests the existence of a broader genetic base to use in Lima bean breeding programs. Studying the effects of climate change on Lima bean is relevant to all three of the working groups within the Lunatus Network: origin and evolution, conservation, and improvement. First, studies of population genomics and local adaptation to climate change are contributing to understanding the origin and evolution of the species. Second, the information on local adaptation and climate change makes it possible to identify which populations will be vulnerable to climate change, and thus coordinate their conservation. Third, the identification of populations resistant to climate change will allow for improvement projects of populations susceptible to climate change. The final goal of the study of the effects of climate change on Lima beans is to carry out frontier research that allows supporting the conservation and permanence of traditional agricultural systems of Lima beans, and thus contribute to human food security in the near future.