The 2009 ASHS Annual Conference

Pressures to restrict water use are increasing in the Southwestern United States in response to drought conditions. The San Diego Water Department reported that as much as 50% of water usage is allocated for landscape use. Utilizing drought tolerant plants within a landscape is a simple strategy for reducing water use. The Intermountain West is a rich resource for plants that have evolved to xeric conditions. Penstemon offers vast genetic diversity and is the largest genus of herbaceous perennials endemic to North America. Breeding programs have already begun and selected improved cultivars using traditional breeding techniques. Our work has utilized flow cytometry to analyze nuclei size and quantitatively estimate the DNA content of more than 50 species. Of the species tested to date P. fasciculatas has been estimated to be smallest genome sizes at just over 764 Mb while P. digitalis has been found to contain nearly 17,775 Mb. Although breeding work has already begun to improve these attractive perennials, expanding our knowledge of these plants on a genetic level will enhance our ability to effectively breed for superior cultivars.