RESEARCH ARTICLE Analysis of genetic diversity in a sweet potato (Ipomoea batatas L.) germplasm collection from Tanzania as revealed by AFLP Abdelhameed Elameen Æ Siri Fjellheim Æ Arild Larsen Æ Odd Arne Rognli Æ Leif Sundheim Æ Susan Msolla Æ Esther Masumba Æ Kiddo Mtunda Æ Sonja S. Klemsdal Received: 29 September 2006 / Accepted: 25 April 2007 / Published online: 30 June 2007 Ó Springer Science+Business Media B.V. 2007 Abstract Sweet potato (Ipomoea batatas L.) is the fifth most important crop in the developing countries after rice, wheat, maize and cassava. The amplified fragment length polymorphism (AFLP) method was used to study the genetic diversity and relationships of sweet potato accessions in the germplasm collec- tion of Sokoine University of Agriculture, Morogoro and Sugarcane Research Institute, Kibaha, Tanzania. AFLP analysis of 97 sweet potato accessions using ten primer combinations gave a total of 202 clear polymorphic bands. Each one of the 97 sweet potato accessions could be distinguished based on these primer combinations. Estimates of genetic similari- ties were obtained by the Dice coefficient, and a final dendrogram was constructed with the un-weight pair- group method using arithmetic average. AFLP-based genetic similarity varied from 0.388 to 0.941, with a mean of 0.709. Cluster analysis using genetic simi- larity divided the accessions into two main groups suggesting that there are genetic relationships among the accessions. Principal Coordinate analysis con- firmed the pattern of the cluster analysis. Analysis of molecular variance revealed greater variation within regions (96.19%) than among regions (3.81%). The results from the AFLP analysis revealed a relatively low genetic diversity among the germplasm acces- sions and the genetic distances between regions were low. A maximally diverse subset of 13 accessions capturing 97% of the molecular markers diversity was identified. We were able to detect duplicates accessions in the germplasm collection using the highly polymorphic markers obtained by AFLP, which were found to be an efficient tool to charac- terize the genetic diversity and relationships of sweet potato accessions in the germplasm collection in Tanzania. Keywords AFLP Á Genetic diversity Á Ipomoea batatas Á Sweet potato A. Elameen Á L. Sundheim Á S. S. Klemsdal (&) Bioforsk–Norwegian Institute for Agricultural and Environmental Research, Plant Health and Plant Protection Division, Department of Genetics and Biotechnology, Hogskoleveien 7, 1432 Aas, Norway e-mail: sonja.klemsdal@bioforsk.no A. Elameen Á S. Fjellheim Á O. A. Rognli Department of Plant and Environmental Sciences, Norwegian University of Life Sciences, P.O. Box 5003, 1432 Aas, Norway A. Larsen Graminor AS, Hommelstadvegen 60, 2344 Ilseng, Norway S. Msolla Department of Crop Science and Production, Sokoine University of Agriculture, P.O. Box 3005, Chuo Kikuu, Morogoro, Tanzania E. Masumba Á K. Mtunda Root/Tuber Crops Programme, Sugarcane Research Institute, P.O. Box 30031, Kibaha, Coast, Tanzania 123 Genet Resour Crop Evol (2008) 55:397–408 DOI 10.1007/s10722-007-9247-0