Genetic variability in grass species along a latitudinal gradient in Patagonia

LEVA P.E., M.R. AGUIAR & A.C. PREMOLI

Bariloche

Congreso; VI Southern Connection Congress; 2010

Our research program studies genecology of Bromus pictus and Poa ligularis two native forage species threatened by sheep overgrazing. Our specific objective was to compare genetic diversity and divergence among and within 6 populations of each species distributed along a latitudinal gradient (ca. 600 km). Leaves from 30 randomly selected individuals from each population were analyzed by isozyme electrophoresis. We estimated genetic variability indexes (Pss, At, Ap, Ar(10%), A, Ae, I, Ho, He) and genetic divergence (distribution of alleles frequencies and Wright’s F statistics). Analysis showed that 8 and 13 loci were polymorphic out of 9 and 19 resolved loci in at least one population for Bromus and Poa , respectively. In both species, rare alleles (