A perspective on the centre-periphery hypothesis: some examples in Petunia and other Neotropical taxa

Abstract

Abstract The Neotropical region holds high plant species richness, and these species originated under the influence of climate changes, tectonic processes and ecological factors. Several genera of Solanaceae have appeared and diversified quickly in the area, producing a high number of species and lineages. Petunia is endemic to the grasslands of southern South America and constitutes one of these young groups. From this perspective, I aim to identify processes driving the diversification of Petunia, review works describing genetic and morphological diversity for species in this genus and compare the evolutionary patterns of this genus with other genera from the Neotropics. The primary process explaining the genetic variability in the genus seems to be migration during the Quaternary period, as observed for other herbaceous species in South America. Molecular, morphological and even mating system diversity seem to follow the centre-periphery hypothesis.