Invasive plants represent a major environmental and economic threat. They erode native biodiversity, decrease crop and pasture production and limit the use of GMO and non-GMO technologies as herbicide and pests resistance owing to the gene flow with crop relatives. In addition, invasive populations represent an ideal model system for studying evolution over contemporary time-scales. Wild sunflower, the ancestor of cultivated sunflower, is native to North America and act as invasive in central Argentina, southern Europe and southern Australia. In Argentina, one of the three largest producers of oil-seed sunflower, wild sunflower was introduced as a forage crop ca. 70 years ago, since it has spread over the central region. Wild sunflower in Argentina is associated to disturbed habitats and was recently found in crop fields as an agricultural weed. In spite of the well-documented case of invasive sunflower in central Argentina, some questions remain unanswered. In this project, we ask the following three questions: 1) was the invasion associated to genetic bottlenecks and founder effects? What is the geographic source of invasive sunflower? Is crop-to wild introgression a causal driver of invasiveness in Argentinean sunflower? Answering these essential questions will shed light on the genetic basis of invasiveness and aid in predicting the risk of crop gene escapes (transgenes or not) from farmer´s fields.