Data from: Water availability as an agent of selection in introduced populations of Arabidopsis thaliana: impacts on flowering time evolution

Flowering is one of the most influential events in the life history of a
plant and one of the main determinants of reproductive investment and
lifetime fitness. It is also a highly complex trait controlled by dozens
of genes. Understanding the selective pressures influencing time to
flowering, and being able to reliably predict how it will evolve in novel
environments, are unsolved challenges for plant evolutionary geneticists.
Using the model plant species, Arabidopsis thaliana, we examined the
impact of simulated high and low winter precipitation levels on the
flowering time of naturalized lines from across the eastern portion of the
introduced North American range, and the fitness consequences of early
versus late flowering. Flowering time order was significantly correlated
across two environments—in a previous common garden experiment and in
environmental chambers set to mimic mid-range photoperiod and temperature
conditions. Plants in low water flowered earlier, had fewer basal branches
and produced fewer fruits. Selection in both treatments favored earlier
flowering and more basal branches. Our analyses revealed an interaction
between flowering time and water treatment for fitness, where flowering
later was more deleterious for fitness in the low water treatment. Our
results are consistent with the hypothesis that differences in winter
precipitation levels are one of the selective agents underlying a
flowering time cline in introduced A. thaliana populations.