Sensitivity and Efficiency of Randomly Amplified Polymorphic DNA for Cultivar Identification in Sweetpotato

Detecting inter- and intra-varietal variation is essential for the management of a plant germplasm bank. The sensitivity and efficiency of randomly amplified polymorphic DNA (RAPD) for cultivar identification and somaclonal mutation in sweetpotato were evaluated. RAPD demonstrated a highly significant inter-varietal variation. Every one of the 23 tested cultivars can be identified with a RAPD profile generated by a single primer. Suspected duplicates that are morphologically indistinguishable can be unambiguously verified with a combination of three decamers. No intra-varietal variation was found using RAPD. Clones of `Jewel' and `Beauregard' collected from different sources all have the same RAPD profiles. Moreover, with 150 markers, the transgenic `Chogoku' sweetpotato cannot be differentiated from its untransformed counterparts, even though the transgenic plant shows significant morphological changes. These results demonstrate that RAPD is a sensitive and efficient tool for identifying cultivar duplicates, but it is not efficient for detecting intra-clonal variation or somaclonal mutation in sweetpotato.