Data from: Continuous inbreeding affects genetic variation, phenology and reproductive strategy in ex situ cultivated Digitalis lutea

Data from several experiments studying population differences between a wild and a botanic garden population and effects of different hand-pollination treatments on various traits of the short-lived perennial plant Digitalis lutea. Separate spreadsheets contain data on 1) genetic variation using ISSR markers, 2) effects of pollination treatments on seed number and seed mass, 3) differences in germination, 4) various traits studied in a common garden experiment, 5) effects of population and pollination treatments on pollinator visitation.

See publication in American Journal of Botany (2022) for details.

Abstract:

Premise: Ex situ cultivation is important for plant conservation, but cultivation in small populations may result in genetic changes by drift, inbreeding or unconscious selection. Repeated inbreeding potentially influences not only plant fitness, but also floral traits and interactions with pollinators, which has not yet been studied in an ex situ context.

Methods: We studied the molecular genetic variation of Digitalis lutea L. from a botanic garden population cultivated for 30 years, a frozen seed bank conserving the original genetic structure, and two current wild populations including the source population. In a common garden we studied the effects of experimental inbreeding and between-population crosses on performance, reproductive traits and flower visitation of plants from the garden and a wild population.

Results: Significant genetic differentiation was found between the garden population and the wild population from which the seeds had originally been gathered. After experimental selfing, inbreeding depression was only found in germination and leaf size of plants from the wild population, indicating a history of inbreeding in the smaller garden population. Moreover, garden plants flowered earlier and showed floral traits related to selfing, whereas wild plants showed traits related to attracting pollinators. Bumblebees visited more flowers of outbred than inbred plants and of wild than garden plants.

Conclusions: Our case study suggests that high levels of inbreeding during ex situ cultivation can influence reproductive traits and thus interactions with pollinators. Together with the effects of genetic erosion and unconscious selection this may affect the success of reintroductions into natural habitats.