#### Abstract
Hybridization is an important evolutionary process that can lead to the introgression of adaptive traits and the formation of new species. However, the role of hybridization in the adaptation of plants to changing climates is not well understood. Here, we investigated the role of hybridization in the adaptation of two closely related fig species, Ficus carica and F. palmata, to their climatic margins. We found that both species showed evidence of hybridization, with the highest levels of hybridization occurring at the climatic margins of their ranges. We also found that hybrids between the two species showed increased tolerance to drought and high temperatures, suggesting that hybridization may be an important mechanism for adaptation to climate change.
#### Introduction
Hybridization is the process by which two different species mate and produce offspring. This can occur naturally or as a result of human intervention. Hybridization can have a number of evolutionary consequences, including the introgression of adaptive traits from one species to another, the formation of new species, and the extinction of one or both parent species.
The role of hybridization in the adaptation of plants to changing climates is not well understood. Some studies have found that hybridization can facilitate adaptation to new environments, while others have found that it can hinder adaptation. It is likely that the role of hybridization in adaptation depends on a number of factors, including the genetic diversity of the parent species, the environmental conditions, and the strength of selection.
#### Methods
We studied two closely related fig species, Ficus carica and F. palmata, that occur in the Mediterranean region. Ficus carica is a domesticated species that is widely cultivated for its fruit, while F. palmata is a wild species that is found in rocky habitats. The two species are very similar in appearance, but they differ in their ecological preferences. Ficus carica is more tolerant of drought and high temperatures than F. palmata.
We collected leaf samples from both species at 10 sites across their ranges. We extracted DNA from the leaf samples and genotyped them at 10 microsatellite loci. We used the genotype data to estimate the levels of hybridization between the two species.
We also conducted a common garden experiment to compare the drought and heat tolerance of hybrids and purebred individuals of the two species. We grew seedlings of the two species and their hybrids in a greenhouse under controlled conditions. We subjected the seedlings to a drought treatment and a heat treatment. We measured the survival of the seedlings after each treatment.
#### Results
We found that both Ficus carica and F. palmata showed evidence of hybridization. The levels of hybridization were highest at the climatic margins of the two species' ranges. This suggests that hybridization may be an important mechanism for adaptation to climate change.
We also found that hybrids between the two species showed increased tolerance to drought and high temperatures. This suggests that hybridization may be an important mechanism for the introgression of adaptive traits between species.
#### Discussion
Our study provides evidence that hybridization can play an important role in the adaptation of plants to changing climates. Hybridization can facilitate the introgression of adaptive traits from one species to another, which can help to increase the fitness of individuals in a changing environment. Hybridization can also lead to the formation of new species, which can further increase the diversity of plant communities.
The role of hybridization in adaptation to climate change is likely to be complex and context-dependent. However, our study suggests that hybridization can be an important mechanism for plants to adapt to the changing climate.
#### Conclusion
Hybridization is an important evolutionary process that can have a number of consequences for the adaptation of plants to changing climates. Our study provides evidence that hybridization can play an important role in the adaptation of two closely related fig species to their climatic margins. Hybridization may be an important mechanism for the introgression of adaptive traits between species and the formation of new species.
