We estimated the genetic diversity of 50 Jatropha curcas Costa Rican samples using 18 EST-SSR, one G-SSR and nrDNA-ITS markers. We also evaluated the phylogenetic relationships among samples using nuclear ribosomal ITS markers. Non-toxicity was also evaluated using G-SSRs and SCARs markers. A Neighbor-Joining (NJ) tree and a Maximum Likelihood (ML) tree were constructed using SSR markers and ITS sequences, respectively. Heterozygosity was moderate (He = 0.346), but considerable when compared to

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... worldwide values for J. curcas. The PIC (PIC = 0.276) and inbreeding coefficient (f = -0.102) were both low. Clustering was not related to the geographical origin of accessions but Costa Rican J. curcas consistently clustered as a separate group. International accessions clustered independently of collection sites suggesting a lack of genetic structure, probably due to a wide distribution of this crop and ample gene flow. Molecular markers identified only one non-toxic accession (JCCR-24) from Mexico. This work is part of a countrywide effort to characterize the genetic diversity of Jatropha curcas germplasm bank in Costa Rica.