Research Journal of Cell and Molecular Biology, 3(2): 71-79, 2009 © 2009, INSInet Publication Corresponding Author: E. Amri, Dar es Salaam Institute of Technology, P.O. Box 2958, Dar es Salaam Email: ezekielamri@yahoo.com, Tel. No. 255 (0754) 2410764, Fax No. 255 (022) 2410764 71 Evaluation of Genetic Diversity in Dalbergia Melanoxylon Populations Using Random Amplified Polymorphic DNA Markers. E. Amri, Z.L. Kanyeka, H.V.M. Lyaruu and A.S. Nyomora 1,2 2 2 2 Dar es Salaam Institute of Technology, P.O. Box 2958, Dar es Salaam 1 Department of Botany, University of Dar es Salaam, P.O. Box 35060, Dar es Salaam 2 Abstract: African Blackwood Dalbergia melanoxylon (Guill. & Perr.) is a tropical tree with high-quality wood and one of the most expensive timbers in the world. Randomly amplified polymorphic DNA (RAPD) analysis was used to determine the genetic diversity within and among six natural populations of D. melanoxylon in Tanzania. A total of 60 individual plants were analysed using 14 most informative RAPD primers which amplified 87 scored bands showing 73·6 % polymorphism. Cluster analysis using unweighted pair group method with arithmetic average (UPGMA) formed four major clusters which illustrated that most individuals from a given population tended to cluster together and were therefore more genetically similar than individuals from different populations. Most of the genetic variations were found to be high within population 63.6% and low among populations 36.4%. The genetic diversity information of D. melanoxylon populations reported in this study is very important component for efficient conservation and effective management of its genetic resources. Key words: Dalbergia melanoxylon, Conservation, genetic diversity, RAPD markers INTRODUCTION Dalbergia melanoxylon (African Blackwood) belongs to the family Leguminosae and is one of the most important indigenous trees in Tanzania. The species has a high-quality wood, which is used for the manufacturing of musical instruments and decorative objects such as carvings that are popular to foreign visitors . As a result of the valuable products derived [2 0 ] from D. melanoxylon, high exploitation pressure has been exerted to the extent of threatening its genetic diversity and future existence in its natural habitats . D. melanoxylon is considered by the IUCN Red [13,20] List as Lower Risk/near threatened (LR/nt) species . [4 1 ] Moreover, this species has serious reproductive limitations, both asexually and sexually with very low germination capacity . Therefore information on [28,30] genetic variability is important for successful management and conservation of the species. Genetic diversity in tropical tree species is being lost rapidly due to the process of deforestation, which has reduced the size of natural populations and eliminated local populations . The situation is [3 1 ] particularly grave with regards to some species of economic importance, such as the D. melanoxylon. Knowledge about genetic diversity and population genetic structure offers baseline information for formulating effective conservation plans, and can often provide novel, conservation-relevant insights . [26,31] Preservation of genetic variation and evolutionary processes in viable populations has an ecological importance of preventing potential extinction for the species . [3 6 ] Different methodologies using molecular markers are widely used to analyse the pattern of variations within and among natural populations of tree species. Among the various markers used, random amplified polymorphic DNA (RAPD) is the most popular DNA based markers . These markers are the [6,22,2,19] technically least demanding and offer a fast method for providing information from a large number of loci, particularly in species where no studies have previously been undertaken. Moreover, in terms of results, the diversity assessed with RAPDs is comparable with that obtained with restriction fragment length polymorphism (RFLP) or allozymes . [9 ] Previous studies in assessing diversity of D. melanoxylon have used morphological methods . [2 5 ] However, the use of morphological markers for estimating genetic diversity in plants have limitations due to effect of stage of development or environment compared to molecular markers . Little information [2 9 ] is available on genetic diversity of D. melanoxylon using molecular markers. Genetic diversity of D. melanoxylon in Ubena and Mkundi populations in eastern part of Tanzania has previously been assessed