Impact of domestication on genetic diversity of Warburgia Ugandensis sprague within Lake Victoria Region
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Date
2013-11-22
Authors
Nkatha, Gacheri Muriira
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Abstract
Warburgia ugandensis Sprague (Canellaceae) occur in East and Central Africa, and is of great medicinal importance. The demand for W. ugandensis bark in herbal medicinal industry has led to unsustainable harvesting in the natural forests thereby threatening the species survival. The species natural habitat is also under threat of clearance for farming. Growing of this species on-farm will ensure sustainable medicinal source and its conservation. The material planted on-farm should be of wide genetic base hence protect subsequent generations of founder effects. However, genetic diversity of material currently on-farm is unknown. The genetic diversity of three on-farm W. ugandensis populations and their proximate natural populations from Lake Victoria region were analysed using the amplified fragment length polymorphism (AFLP) markers. Three reference populations each from Kenya, Uganda and Tanzania were also incTuded in the study. Twenty primer pairs were initially used in the screening for polymorphisms, of which four primer pairs were selected for the final analysis. Genetic diversity estimate, genetic distances and phenograrn was developed using TFPGA 1.3 statistical software.
Analysis of molecular variance (AMOVA) and principal coordinate analysis (PCA) were generated using GenAlEx 6.3 molecular statistical software. Four primer combinations (EcoRI+ACC/MseI+CAA, EcoRI+ACTlMseI+CAT, EcoRI+ACT/MseI+CAG, and EcoRI+AGC/MseI+CAG) produced 223 polymorphic bands. Both the natural and onfarm populations had high genetic diversity ranging from H = 0.2892 to H = 0.1278. Principal co-ordinate analysis and phenogram showed the ten populations falling into two major groupings of Kenya and Tanzania, with Uganda populations splitting into the two
groupings; this is probably because Uganda is believed to be the centre of diversity for Warburgia ugandensis. The two cluster. analyses revealed close genetic relatedness between the on-farm and their proximate natural population. The AMOVA showed 54 % of the variation to be within populations and 46 % among populations (P<O.Ol). These study findings are in agreement with earlier suggestions that most of the trees on-farm areremnants of forest in cultivated forest lands. These revealed close genetic relationship between the on-farm and their proximate natural population. The high genetic diversity of
W. ugandensis populations currently on-farm suggest that the material can be used for
future seed sources and conservation of the species
Description
Department of Biochemistry and Biotechnology, 68p. 2012
Keywords
Medicine plants --Kenya, Canellaceae --Kenya