Figure 1
From: Hybridization speeds adaptive evolution in an eight-year field experiment
Field experimental evolution design. (a) Resynthesized hybrids were created by crossing H. a. annuus with H. debilis to form an F1 generation, then backcrossing this F1 generation to H. a. annuus to establish a hybrid BC1 seed stock. Sizes of illustrated inflorescences are approximately proportional to actual. (b) Initial populations of 500 individuals of Control (H. a. annuus, orange background) and Hybrid (BC1, dark blue background) were established in 2003 at separate plots at Lady Bird Johnson Wildflower Center (LBJ). A second Hybrid line was established at the Brackenridge Field Laboratory (BFL, light blue background). Lines were allowed to establish and reproduce naturally in situ for seven generations. Each generation, seeds were collected and stored from 96 randomly-chosen individuals per line. In 2017, a final common-garden was planted at LBJ with both control and hybrid seeds from generations one and five through eight for LBJ, generations one and eight for BFL, and accessions of locally-adapted H. a. texanus (not shown) for comparison.
