DISSERTATION RESEARCH: Interrelationships Among Perianth Size, Inbreeding, and Divergence in the Plant Boerhavia (Nyctaginaceae)

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This research concerns a group of approximately 22 plant species that has diversified in the Sonoran and Chihuahuan Deserts, the genus Boerhavia. Species of Boerhavia can self-pollinate, and also have very different flower sizes, which affects how often insects visit and transfer pollen between plants. This project tests whether species with smaller flowers have a greater amount of genetic differentiation between populations that are highly inbred, because pollen can not frequently flow between populations. Genetic fingerprinting techniques will establish the proportion of seeds on a plant that are sired by other individuals. This will be done for many individuals per population, for all North American species. The same data will also provide estimates of the differences between populations, and their level of inbreeding. Combining this data with the evolutionary history of Boerhavia, it will be possible to test whether species with smaller flowers exhibit populations diverging into genetically distinct species.This project will provide training for N. Douglas in botany and population biology. Mexican botanists are collaborating in this research. The project will estimate the total genetic diversity of four extremely rare, unprotected species in the U.S. and Mexico. Thus, it will find an audience among botanists, ecologists, and conservationists in both nations.