How the Cultivation of Wild Plants in Botanic Gardens can Change their Genetic and Phenotypic Status and What This Means for their Conservation Value

The discipline of horticulture, growing and propagating plants under artificial conditions, has a centuries-long tradition and has developed into a vital industry of breeding, propagating and trading ornamental and wild plants around the globe. Botanic gardens have always been at the centre of horticultural training and have provided excellence and advancements in the field. In recent decades, botanic gardens have also become an active part of ex situ conservation activities by storing seeds of endangered wild plants, growing living collections for conservation purposes, or propagating plants for direct reintroduction measures. While this shift in focus has been necessary and very important, ex situ collections of wild plants have been criticised for beinggenetically impoverished, potentially hybridised with congeners, or adapted to the artificial garden conditions and potentially having lost specific adaptations to their original wild habitat. In this review, we provide an overview of these potential threats to wild plants in ex situ living collections and outline examples of how ex situ cultivation can affect genetic diversity, trait expression and adaptive responses of the plants. We evaluate what these changes could mean for the conservation value of the collections, and discuss how they could be avoided by refining horticultural practices.