The genetic divergence of populations is considered an important step towards speciation. However, the degree to which natural plant populations have diverged for quantitative traits is unclear because of maternally biased estimates of differentiation. The goal of Dr. Kelly's research planning grant is to use an elevational gradient to determine whether life history, morphological, and fitness traits have evolved in response to climatic variability in the goldenrod species Solidago macrophylla, a native perennial plant of northeastern North America. Clinal variation in plant phenotype will be correlated with elevational variation in environmental conditions that may be acting as selective forces for the evolution of fitness-related features of plant size and reproductive condition. Subsequent research will consist of a series of reciprocal transplant experiments that are designed to distinguish paternal (pollen) effects from maternal contributions (chloroplast, mitochondria, endosperm) to phenotypic variation both within and among populations. The latter research component is a novel and important addition to traditional reciprocal transplant studies that have usually failed to control for local versus long-distance pollination. %%% Research on Solidago macrophylla will be the first to estimate the level of genetic differentiation for quantitative traits among populations while controlling for maternal bias (effects of local sources of chloroplasts, mitochondria and endosperm). The results of the study will augment understanding of the degree to which quantitative life-history traits in plants have evolved in response to natural selection. In addition, the results will clarify patterns of genetic diversity among populations for quantitative traits, information that is necessary for effective conservation of rare and endangered plants.
