Abstract
Climate change may hinder species' ability to evolutionarily adapt to environmental shifts. Assisted gene flow, introducing adaptive alleles into target populations, could be a viable solution for keystone species. Our study aimed to evaluate the benefits and limitations of assisted gene flow in enhancing the evolutionary potential of Lupinus angustifolius L. (Fabaceae), considering both phenotypic and genomic perspectives. We collected seeds from four populations in Spain at two latitudes (north and south), and grew them in a common garden. We used pollen from southern individuals to pollinate northern plants and create an F1 gene flow line that would advance its flowering onset. In the next season, we allowed F1 plants to self-pollinate creating an F2 self-pollination line. We also created a backcross line by pollinating control northern plants with pollen from F1 plants. We measured flowering onset, reproductive success, and other plant traits in all resulting lines. In parallel, we sequenced genes related to reproduction, growth, stress, nitrogen, and alkaloids. All gene flow-derived lines flowered significantly earlier than the control lines from the northern populations. F1 gene flow line plants produced heavier seeds and had a lower shoot growth than those from the northern control lines. Genomic analyses identified 36 outlier SNPs between the control and the F1 gene flow lines, associated with differences in flowering onset, seed weight, and shoot growth. These results underscore that assisted gene flow can enhance a population's evolutionary potential by altering specific traits. However, altering one trait may impact others in a way that depends on the intrinsic characteristics of each population.