Soil fertility is an important determinant of plant productivity in natural and managed ecosystems. Native plants from low nutrient habitats have been characterized for traits that are hypothesized to account for the native plant ecological and evolutionary success. These traits are generally thought to allow plants to reduce nutrient demand, increase retention, and/or increase uptake capacity. However, the ecological and evolutionary advantages of these individual traits, and their genetic bases, have not been demonstrated. The proposed research will use a desert sunflower species of hybrid origin and its ancestral parent species to investigate the ecology and evolution of plant nutrient relation traits in infertile habitats. Compared to its ancestral parent species, Helianthus anomalus is endemic to a low nutrient habitat and has traits consistent with low nutrient adaptation. The research will 1) test the advantage of individual traits and 2) identify the genetic and genomic basis of those traits, and 3) determine how those traits respond to selection. The experiments will be carried out as a series of controlled environment and field studies. The integration of ecophysiological, quantitative genetic, and genomic perspectives will provide insight into the evolutionary forces that have shaped H. anomalus, and more generally to the process of selection that leads to adaptation to low nutrient habitats. This study will contribute to the understanding of traits that could maximize crop productivity under marginal conditions. Helianthus annuus is one of the ancestral parents of H. anomalus and domesticated H. annuus is an economically important crop species. Thus, H. anomalus and synthetic hybrids representing its putative ancestors may serve as donors for genes to improve H. annuus productivity under lower nutrient conditions, reducing fertilizer requirements and decreasing impacts of agricultural runoff. This study will also provide an opportunity for numerous undergraduate students to gain a substantial research experience.
