The shade avoidance syndrome, the ability of plants to elongate and flower earlier in response to foliage shade, is an ecologically and agriculturally important example of phenotypic plasticity that may facilitate plant persistence across a range of light conditions. Despite the apparent adaptive value of the shade avoidance syndrome, there is variation in the syndrome between populations of many species. Functional arguments suggest that selection may favor shade avoidance in open canopy sites but not closed canopy sites. Here population differentiation in shade avoidance will be examined in seven pairs of open canopy and woodland populations of the annual species Impatiens capensis. The adaptive significance of differentiation in shade avoidance will be tested by comparing quantitative trait variation to neutral marker variation partitioned between canopy types and among sites. Potential constraints on shade avoidance will be examined by testing for genetic correlations between traits related to shade avoidance and traits related to light sensitivity in other life stages.
This research will improve our understanding of an ecological and agriculturally important trait, and will enrich graduate education by promoting training in molecular tools and fostering collaboration between ecological geneticists and systematists at separate institutions.
