We estimated the genetic diversity of 50 Jatropha curcas 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. Nontoxicity 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

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... compared to worldwide values for J. curcas. The PIC (PIC = 0.274) and inbreeding coefficient (f = -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 Jatropha curcas germplasm bank in Costa Rica. PeerJ reviewing PDF | Manuscript to be reviewed 23 ABSTRACT 24 We estimated the genetic diversity of 50 Jatropha curcas samples from the Costa Rican 25 germplasm bank using 18 EST-SSR, one G-SSR and nrDNA-ITS markers. We also evaluated the 26 phylogenetic relationships among samples using nuclear ribosomal ITS markers. Non-toxicity was 27 evaluated using G-SSRs and SCARs markers. A Neighbor-Joining (NJ) tree and a Maximum 28 Likelihood (ML) tree were constructed using SSR markers and ITS sequences, respectively. 29 Heterozygosity was moderate (He = 0.346), but considerable compared to worldwide values for J. 30 curcas. The PIC (PIC = 0.274) and inbreeding coefficient (f = -0.102) were both low. Clustering 31 was not related to the geographical origin of accessions. International accessions clustered 32 independently of collection sites, suggesting a lack of genetic structure, probably due to the wide 33 distribution of this crop and ample gene flow. Molecular markers identified only one non-toxic 34 accession (JCCR-24) from Mexico. This work is part of a countrywide effort to characterize the 35 genetic diversity of the Jatropha curcas germplasm bank in Costa Rica. 36 37 38 39 40 41 PeerJ reviewing PDF |