Mercer Lab

Nitrogen is an essential nutrient for plants and inorganic fertilizers used to promote plant growth account for between 1%-2% of total global fossil fuel usage. Some plants, especially legumes, are capable of forming associations with nitrogen-fixing microbes to convert atmospheric nitrogen into a form that the plant can utilize.

Diverse types of chile peppers grow along an environmental gradient from warm and humid coastal areas to the cool, dry highlands in their native Mexico. These environmental gradients encompassing fascinating diversity present an opportunity to study environmental adaptation and the process of domestication. Using a combination of next generation sequencing technologies, population genetics, phenotyping techniques, and bioclimatic data, we are working to identify a genetic basis to abiotic stress tolerances.

Natural and human mediated processes have shaped crops grown throughout the world. In crop centers of origin where landraces still grown, we can investigate how farmers and environmental conditions have collaborated to produce the crop diversity that exists on the landscape. However, in this time of rapid global change, it is also important to consider how this diversity will respond to future climatic and technological change.

With the advent of transgenic crops and the potential for transgenes to escape cultivation, studies of crop-wild gene flow became essential to better understand how evolutionary processes act on crop alleles in wild populations. Although some crop traits, such as lack of shattering, can be expected to reduce fitness under wild conditions, others, such as early flowering, may be more universally beneficial. We study the ways that genetic and environmental variation affects the likelihood that crop alleles or traits may introgress into wild populations.

Climate change is already altering the phenology and productivity of many plant and animal species. Depending on each species' capacity for plasticity, as well as its ability to evolve or migrate, some will be more susceptible than others altered biotic and abiotic conditions. Crop species may vary in their responses to climate change depending, in part, on their pollination systems. We investigate how productivity of monoecious crops (those with separate male and female flowers on the same plant, e.g., squash) may be affected by altered phenology and reproductive synchrony.