Evaluation of genetic diversity between toxic and non toxic Jatropha curcas L. accessions using a set of SSR markers

Scepticism about Jatropha as a competitive biofuel feedstock especially on marginal soils has been growing; in fact, the jatropha-biofuel chain is risky economically and often financially unfeasible without significant government subsidies under these conditions. A valorization of the by-products and in particular of the extruded seed cake (about 70% (w/w) of the processed seed), as animal feed, currently prevented by the presence of phorbol esters (PE) toxins, could contribute to a significant improvement in the economic sustainability of the crop. Strategies for breeding improved varieties could be accelerated by DNA-based molecular marker technology. Wild Mexican accessions and accessions from other parts of the world (South America and Africa) were analyzed by 40 simple sequence repeat (SSR) markers. SSR primers were chosen on the grounds of their Tm, length, degree of polymorphism and specificity for toxic trait. The genetic study pointed out a high degree of similarity both within and among the non Mexican accessions. The Mexican accessions proved to be non toxic and genetically differentiated forming a well separated cluster from out of Mexico accessions. Some polymorphic loci were close correlated with the character toxicity and useful, once validated their association in segregating populations for Marker Assisted Selection (MAS).