African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12125

Full Length Research Paper

Simple sequence repeat (SSR) diversity of cassava in South, East and Central Africa in relation to resistance to cassava brown streak disease

A. Pariyo1,2, P. Tukamuhabwa1, Y. Baguma2, R. S. Kawuki2, T. Alicai2, P. Gibson1,3, E. Kanju4, B.W. Wanjala5, J. Harvey5, I. Nzuki5, I. Y. Rabbi6 and M. Ferguson6*
1Makerere University, Department of Agricultural Production, P.O. Box 7062 Kampala, Uganda.  2National Crops Resources Research Institute (NaCRRI), P.O. Box 7084 Kampala, Uganda.  3Southern Illinois University, Department of Plants, Soils, Agricultural Systems, Carbondale, IL, USA. 4International Institute of Tropical Agriculture (IITA), P.O Box 34441, Dar Es Salaam, Tanzania.  5Biosciences eastern and central Africa (BecA) Hub ILRI, P.O. Box 30709, Nairobi 00100, Kenya. 6International Institute of Tropical Agriculture (IITA), c/o International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi 00100, Kenya.
Email: [email protected]

  •  Accepted: 05 July 2013
  •  Published: 31 July 2013

Abstract

This study was conducted to: (1) determine the amount and structure of the genetic diversity of cassava in southern, eastern and central (SEC) Africa using simple sequence repeat (SSR) markers, (2) determine the frequency and distribution of alleles putatively associated with resistance to cassava brown streak disease (CBSD) derived from the variety ‘Namikonga’, and (3) examine the genetic relationships among some CBSD resistant genotypes. The major findings from this study were: (1) little genetic differentiation was confirmed among countries (7%) with the majority of variation distributed among individuals (93%), (2) the frequency of alleles putatively associated with resistance to CBSD was found to be generally low (0.2 to 0.5) but widely dispersed in the cassava germplasm of the SEC Africa region implying that if validated the markers will be useful for marker-assisted breeding on a broad scale, (3) several distinct putative sources of resistance to CBSD seem to be present in the cassava germplasm of SEC Africa offering the potential to pyramid genes for more effective and durable resistance and (4) it may be more informative to assess cassava diversity in the SEC Africa region based on pedigree (if known) or genetic relatedness, rather than geographical origin.

Key words: Cassava brown streak disease (CBSD), simple sequence repeat (SSR), genetic diversity, pedigree information.

Abbreviation

AbbreviationsSEC, South, East and Central; CBSD, cassava brown streak disease; CMD, cassava mosaic disease; SSR, simple sequence repeat; QTLs,quantitative trait loci; MAS, marker-assisted selection; SNP, single nucleotide polymorphism.

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