African Journal of
Plant Science

  • Abbreviation: Afr. J. Plant Sci.
  • Language: English
  • ISSN: 1996-0824
  • DOI: 10.5897/AJPS
  • Start Year: 2007
  • Published Articles: 727

Full Length Research Paper

Determining genetic diversity based on ribosomal intergenic spacer length variation in Marama bean (Tylosema esculentum) from the Omipanda area, Eastern Namibia

E. Nepolo1, P. M. Chimwamurombe1*, C. A. Cullis2 and M. A. Kandawa-Schulz3
  1Department of Biological Sciences, University of Namibia, P. Bag 13301, Windhoek, Namibia. 2Department of Biology, Case Western Reserve University, Cleveland, Ohio, USA. 3Department of Chemistry and Biochemistry, University of Namibia, P. Bag 13301, Windhoek, Namibia.
Email: [email protected]

  •  Accepted: 27 July 2010
  •  Published: 30 September 2010



Marama bean [Tylosema esculentum (Burchell) L. Schreiber] is an under-utilized non-nodulating legume, native to the arid and semi-arid areas of Southern Africa, including Namibia, South Africa and Botswana. Its primary benefit to man is based upon the high nutritional value of the seeds. The protein content is slightly higher than that of soybeans and the oil content is twice that of soybeans and approaches that of peanuts. There is an increasing interest in its cultivation, due to its potential as a cash crop and food source, especially in the face of climate changes. In this study, the intergenic spacers (IGS) region of the large ribosomal DNA gene was amplified to assess length variation in Marama bean. A pair of primers based in the conserved ribosomal DNA coding region, but both reading out the coding region, was used to amplify the IGS that separates the repeat units within the tandem arrays of the ribosomal DNA (rDNA) genes. A total of 79 scorable bands were generated by the primer pair used, of which 7 alleles were polymorphic. The rDNA genes proved to be a useful tool for identifying the genetic variation of Marama bean which will be the basis of its effective domestication.


Key words: Marama bean genetic diversity, rDNA gene, intergenic spacer,Tylosema esculentum.