Assessing genetic diversity in Festuca pallescens along a rainfall gradient in Nord Patagonia

LÓPEZ ALDANA SOLEDAD; SIFFREDI GUILLERMO LORENZO; BECKER GUILLERMO ; LÓPEZ DARDO RUBÉN; MARCHELLI PAULA

Capital Federal

Simposio; 5th International Symposium of Forage Breeding; 2015

Festuca pallescens is a native keystone forage grass in Nord Patagonia. It is highly preferred by herbivores, so it has been affected by overgrazing since the beginning of the century. The species has a wide distribution, occurs in diverse environments (e.g. type and depth of soils) and ecological areas with different precipitation regimen in Patagonia. But, the density of its populations declines from west to east, related to a reduction of wetlands along a precipitation gradient. This gradient is expected to become sharper according to climate change predictions and it is relevant to find out the strategies of the species to surpass these changes. It is unknown if the ability of the species to inhabit different environments is due to local adaptation or phenotypic plasticity. In order to contribute in the elucidation of these strategies we begin studies of genetic variation along an environmental gradient. We worked on five sampling sites (Peninsula Huemul, San Ramon, Pilcaniyeu, Ing. Jacobacci and Somuncura Plateau) situated along a West-East oriented transect in Río Negro province. The average annual rainfall in millimetres (mm/a) and coefficients of variation (cv) vary notably between sampling sites (from of 831.6 mm/a; cv 0.2 in the west to 170.8 mm/a; c.v. of 0.436 in the east). In each site, two different altitudes were selected and sampled for genetic characterization, totalizing 10 sampled locations. DNA was extracted from leaves from thirty individuals of each population. At the moment, genetic diversity was assessed with 7 out of 11 polymorphic microsatellite loci (SSR) developed for other species of Poaceae and probed polymorphic also in Festuca pallescens. These molecular markers allowed us to detect until now a total of 55 alleles. The number of alleles per locus varied from 4 to 18. We also found unique alleles in one of the populations for two SSRs. So far, we detected genetic structure among the different populations of the species along the rainfall gradient. These results will be combined with common garden essays to establish a connexion between genetic and morphological analysis to gather primary information for incipient forage breeding plans.