PCR-Based Characterization of Dasheen (Colocasia sp.) and Cocoyam (Xanthosoma sp.)

Dasheen (Colocasia sp.) and cocoyam (Xanthosoma sp.) are two important tuber crops used extensively; they have nutritional and medicinal properties and are used as a source of carbohydrates and calories. Traditional classifications of dasheen and cocoyam are based on morphological, biochemical and agronomical characterization. However, the high degree of morphological and agronomical similarity makes it difficult to distinguish between the two aroids at the species and variety levels. In this study, Random Amplified Polymorphic DNA (RAPD) analyses, UPGMA clustering, -(CA)8RY- microsatellite repeat unit, chloroplast- (trnR/Q 01; trnL 03/04) and mitochondrial-specific (NAD 4.2/4.3; rps14/COB) primer pairs identified two species of dasheen, one of which has 3 varieties. Of the 18 accessions assessed, 11 were identified as either C. esculenta var. esculenta or C. esculenta var. antiquorum. The study also revealed 4 species of Xanthosoma including X violaceae among the accessions of cocoyam assessed. Random 10-mer primers, -(CA)8RY- repeat, chloroplast- (trnR/Q 01) and mitochondrial-specific (NAD 4.2/4.3) primer pairs revealed polymorphism in the plastid and mitochondrial genomes that can be used to differentiate between cocoyam and dasheen. The trnL 03/04 chloroplast-specific amplification profile of dasheen accession DSC4 identified 2 trnL sequences; however, most plants possess a single trnL sequence.