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Title: Morphological and Molecular Diversity, Phylogeography and Ethnobotany of Prunus Africana (Hook, F.) Kalkman in Ethiopia
???metadata.dc.contributor.*???: Prof. Endashaw Bekele
Mihretie, Zivtn
Issue Date: Jun-2014
Publisher: Addis Ababa University
Abstract: This dissertation reports diversity, phylogeography and ethnobotany of Primus africana ( Hook, f.) Kalkman in Ethiopia. P. africana is an economically important, but endangered tree species of Africa. Five quantitative morphological traits were studied in situ on 21 natural populations of P. africana over its distribution range in Ethiopia, and the following mean values were found: total height (19.3m), bole height (7.4m), diameter at breast height (70.2cm), bark thickness (20.3mm), and fresh bark mass (159.6kg). ANOVA based on the five traits revealed that there was significant variation among populations (P < 0.001 ), which could be due to environmental and/or genetic or age structure differences. Pearson’ s correlation analysis revealed significant positive correlations among all traits (except bole height vs. bark thickness) (P < 0.01). Furthermore, all traits (except bark thickness) showed significant negative correlations with altitude (P < 0.05). Six nSSRs and five cpSSRs were used to study molecular genetic diversity and structure of the 21 P. africana populations. A total of 89 nSSR and 14 cpSSR alleles, and 16 chloroplast haplotypes were found. The study showed that P. africana in Ethiopia maintains high levels of diversity in both nSSR (H r = 0.725) and cpSSRs (hr = 0.703). AMOVA revealed that most (88.05%) of the nuclear genetic variation occurs within populations; whereas nearly half (47.8%) of chloroplast genetic variation occurs among populations. There was moderate nuclear (FST = 0.122) and high chloroplast (GST = 0.478) genetic differentiation among populations (P < 0.001). Distance-based clustering (PCoA and UPGMA) and individual-based population assignment methods as well as comparison of observed and permuted differentiation indices revealed geographic pattern for nSSR diversity, but no geographic pattern for cpSSR diversity, which could be due to differences in the effect of genetic drift and/or the mechanism of gene flow between cpDNA and nDNA. However, Mantel test indicated significant positive correlation between geographic and genetic distances for both nSSR (Rxy = 0.126) and cpSSR (Rxy = O.107) (P = 0.001 ). The ethnobotanic study confirmed the multipurpose character of P. africana, and six major use categories (medicinal, construction and carpentry, fuel /firewood, beverage preparation, apiculture, and traditional rituals) were determined for the species. Significant genetic differentiation in more than 95 % of the population pairs suggests that almost all the populations deserve conservation, but as there are often limitations of resources to conserve such a large number of populations, prioritization may be needed. Thus, based on a weighted-score population prioritization matrix that integrates genetic, morphological , conservation status, and ethnobotanic criteria; Kuni, Jimma, and Assela are the top three priority populations for conservation of the species.
Description: A Thesis Submitted to the Department of Microbial, Cellular and Molecular Biology Presented in Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Biology (Applied Genetics)
Appears in Collections:Thesis- Microbial, Cellular and Molecular Biology

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