Genetic Affinities of Jatropha with Other Euphorbiaceous Taxa

The genetic relatedness of Jatropha with other economically important members of the family Euphorbiaceae has been studied. Keeping in view the morphological resemblances of different species of the genus Jatropha, particularly with Ricinus, attempts were made at intergeneric hybridization between the two genera. Protein and molecular profiles showed that Ricinus is genetically distant to Jatropha. Intergeneric crosses and pollen-pistil interactions revealed that the sexual crossability between members of these two genera is limited by incongruity rather than a genetically-controlled incompatibility mechanism. Genome sequencing and molecular phylogenetic studies of different Euphorbiaceous genera indicated the relatedness of Jatropha with cassava (Manihot esculenta). In the recent past, molecular markers and microsatellite markers viz., genic and genomic SSRs developed for Hevea, Manihot, Ricinus and Jatropha are being tested for cross-taxa transferability to facilitate marker-assisted breeding programmes. Likewise, with the draft genomes in place for castor and jatropha – besides the framework linkage maps of Hevea and cassava – it should be feasible to analyze and unravel the various regulatory mechanisms through structural and functional genomics.