Patterns of genetic diversity and potential ecological niches of Stylosanthes species from northeastern Argentina

Abstract

The Stylosanthes genus is native to Central and South America and contains several of the most important tropical legumes used for forage. The southernmost natural distribution of the genus includes the northeast of Argentina, a subtropical region where several phytogeographic provinces and ecoregions converge, giving rise to particular environmental conditions. Here, we used inter-simple sequence repeat markers to evaluate the genetic diversity and genetic structure of four and eight natural populations from northeast of Argentina of Stylosanthes guianensis (Aubl.) Sw. and S. hippocampoides Mohlenbr., respectively. We also modeled the potential ecological niches to obtain environmental information regarding new collection areas and future crop areas. High genetic diversity and specific bands were found for both species. The summary statistics were relatively higher for S. guianensis than for S. hippocampoides. In both species, more genetic diversity was present among populations than within them, and correlation between genetic and geographic distances was observed. Populations were grouped according to their respective species, and their geographical source. The results suggest that collecting a few individuals from a large number of different sites would be an appropriate method for conserving the diversity of these species, with emphasis on those areas with the highest levels of genetic diversity. The modeling of ecological niches suggested mean temperature of the coldest quarter as the most important bioclimatic variable influencing S. guianensis distribution, and temperature seasonality as the variable influencing S. hippocampoides distribution, and showed new potential areas for future collections and as potential crop areas of the species.