Most plant populations will be structured genetically in space as a result of restricted gene flow and spatially heterogeneous selection. However, the fine scale causes and consequences of within population genetic structure remain obscure. The proposed research is aimed at determining the pattern of fine scale spatial genetic structure in populations of the montane herb Delphinium nelsonii and understanding how the pattern is produced. Two populations will be sampled hierarchically to quantify genetic structure at wide range of spatial scales. In each population, individuals from several stages in the life cycle will be genotyped using isozyme electrophoresis. Adult population structure will be characterized using three methods and compared to patterns estimated from empirical measures of pollen and seed dispersal distances. Deviations in genetic diversity and population structure among different life history stages will be used to identify the timing and possible mechanisms of population subdivision. Two techniques will be used to estimate the effects of heterozygosity and inbreeding on offspring survival. Controlled crosses between individuals of different combinations of spatial proximity and genetic similarity will be made. Three measures of fitness, seed set, seed mass, and seed weight will be measured in the resulting progeny. Analysis of variance will be used to decompose the relationship of genetic similarity at electrophoretic marker loci and spatial proximity on the fitness consequences of outcrossing distance.
