Molecular characterization and genetic diversity of <i>Jatropha curcas</i> L. in Costa Rica

Abstract

We estimated the genetic diversity of 50 <i>Jatropha curcas</i> samples from the Costa Rican germplasm bank 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 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 compared to worldwide values for <i>J. curcas</i>. The PIC (PIC = 0.274) and inbreeding coefficient (<i>f</i> = - 0.102) were both low. Clustering was not related to the geographical origin of accessions. International accessions clustered independently of collection sites, suggesting a lack of genetic structure, probably due to the 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 the <i>Jatropha curcas</i> germplasm bank in Costa Rica.