Data from: Adaptation of perennial flowering phenology across the European range of Arabis alpina

Perennial Arabis alpina has a wide geographic distribution and is adapted to local environments. However, the traits that underlie adaptation are unknown. Flowering phenology is an adaptive trait in other species, but its geographic variation has not been systematically studied in herbaceous perennials. Accessions of A. alpina were collected across the European range. Their flowering behavior was tested in controlled conditions, in experimental common-garden plantations at native sites and in-situ in natural populations. Also, genetic diversity within and among populations was examined. French Alpine and Scandinavian accessions varied in timing and duration of flowering. By contrast, in controlled conditions and in-situ, all Spanish accessions were obligate vernalization-requiring with a short duration of flowering. Nevertheless, Spanish populations were as genetically diverse as French Alpine populations and more so than Scandinavian populations. Furthermore, perpetual flowering 1, a mutant that shows no vernalization requirement and a long duration of flowering, showed higher mortality and poorer performance than local accessions at Spanish experimental sites. We propose that in this perennial species, the vernalization requirement and short duration of flowering are under selection in Spain as a strategy to survive exposure to longer, warmer growing seasons.