Assessment of genetic diversity in different accessions of Jatropha curcas

The aim of this work was to estimate the genetic diversity among 273 Jatropha curcas L. accessions and to develop a new SNP-based multi-allelic marker assay (Intra-Locus SNP Haplotype, or LSH) to enhance the genetic discriminatory power of the SNP marker system. The accessions were collected in 15 countries of 3 continents (Africa, Asia and America) and analyzed with SSR, EST-SSR and SNP markers. Cluster analysis revealed the presence of two main genetic groups with an extreme high genetic uniformity and homozygosity of accessions grown in all countries of Africa, Asia, South America, and in some states of Mexico. Differently, an increased genetic variability and heterozygosity was observed in other states of Mexico and Guatemala. The newly developed LSH assay successfully identifies multiple alleles at the same locus and increased the average polymorphic information content of the SNP system. These results confirm the general idea recognizing the Central America region as the center of origin of the species and the genetic homogeneity of the world-wide cultivated accessions, and propose a new powerful SNP-based multi-allelic marker assay for enhancing genetic diversity analysis and selection methods in breeding programs.