The Jasieniuk lab studies agricultural weeds and invasive plants. Our research addresses two basic problems: (1) how agricultural weeds and invasive plants are introduced, establish and spread in new areas and (2) how they evolve in response to changing environments, including management practices. We use a diversity of approaches, including molecular, genetic, demographic, and landscape-level field studies to address these questions.
One of the most challenging and costly problems facing agriculture today is the evolution of resistance to herbicides in cropland weeds. Introduced roughly 60 years ago, herbicides revolutionized agricultural production by markedly reducing human labor requirements and increasing crop yields and yield stability. Their widespread and repeated use exerted strong selection on weed populations, however, and resulted in the rapid evolution of resistance in many species. Our research combines landscape-level field collections and surveys of crop management practices with genetic, molecular and experimental studies to elucidate the evolution and spread of herbicide resistance in weed populations of California cropland.
During invasive spread of nonindigenous plant species, recurrent introductions from single or multiple source populations, founder events, and population bottlenecks lead to the spatial structuring of genetic variation across the invaded range. Geographical patterns of population genetic structure thus often provide information on sources of invasion, pathways of spread, and demographic processes underlying range expansion. Our lab uses highly variable nuclear DNA markers and chloroplast DNA sequences, combined with analyses of population genetic diversity and structure, to identify the origins, trace the spread, and characterize the demographic history of invasive plant species in California.