GENETIC-VARIATION OF SWEET-POTATOES (IPOMOEA-BATATAS L) CULTIVATED INCHILE DETERMINED BY RAPD

RAPD (randomly amplified polymorphic DNA) technology was applied to an alyze the genetic variability of sweet potato germplasm existing in Ch ile and elsewhere. Analysis of 28 cultivars from all over the world sh owed polymorphic bands with all 18 primers tested. A total of 124 RAPD bands were scored with an average of 6.9 polymorphic bands per primer . These results confirm that sweet potato exhibits high genetic variat ion. Two groups were distinguished: one containing Peruvian cultivars, and another containing cultivars from the rest of the world. Analysis of 14 accessions from Central Chile and one from Northern Chile showe d polymorphic bands with 24 of 26 primers tested, but almost all of th e 140 polymorphic bands merely showed the distinctness of the Northern accession. The almost complete uniformity of the other 14 accessions shows that sweet potato germplasm collected in Central Chile has very little genetic variability and may be derived from a single cultivar. Based on these results and on historical records, some hypotheses are proposed to explain the origin of sweet potatoes cultivated in Chile.