More on the introduction of temperate maize into Europe: large-scale bulk SSR genotyping and new historical elements

Abstract

The commonly accepted scenario for the spread of maize into Europe is a single introduction followed by a slow adaptation to temperate climates. With the purpose of clarifying the origins and modalities of maize introduction in Europe, we conducted an extensive survey of 275 maize populations from both American and European origins by using microsatellite (SSR) analysis on pools of individuals. Our data strongly support two major sources, one from the Caribbean and one from northeastern America, giving rise to most of the open pollinated varieties cultivated in Europe. A detailed historical analysis confirms a first introduction of maize in southern Europe by Columbus, and suggests that introduction(s) of temperate northeastern American maize should have occurred at the beginning of the 16th Century at the time of Spanish or French expeditions. In addition, our results reveal that maize varieties cultivated at middle latitudes in Europe likely resulted from hybridization between the southern and northeastern European varieties.