thesis

Study of genetic diversity and micropopagation of Coffea arabica L. and evaluation of genetic diversity in Cocos nucifera L. from Tanzania

Abstract

RAPD and ISSR markers were used to analyze diversity in Coffea arabica L. and Cocos nucifera L. In coffee, both markers revealed within-provenance dissimilarity values that were lower than between-provenance values which accentuates the inbreeding nature of C. arabica and the effect of farmers’ selection. ISSR analysis separated diploid coffee species from C. arabica. Overall provenances from the same location clustered together, provenances from Mbeya were clearly differentiated from the rest. In Cocos nucifera L. RAPD markers were used to analyse 120 accessions. Data were analysed by clustering based on Jaccard’s (1908) coefficient and Nei genetic distances. Further analysis involved principal coordinate analysis (PCA) and bootstrap analysis. The results were able to discriminate between the different provenances and provide evidence of the different origins for the coconut palms in the northern and southern parts of Tanzania. The two major clusters also concur well with the history and distribution of coconuts in Tanzania. Development of a micropropagation protocol for new Coffea arabica L. varieties proceeded with testing five varieties on several media. Several benzyladenine (2.5, 5 and 10 μM) and triacontanol (2.85 and 11.38μM) combinations were tested. Segments from different positions of the leaf were tested for their ability to produce embryos. Leaf segments did not differ in percent embryo-producing explants. BA had the most impact on the number of embryo-producing explants. The best combination of BA/TRIA was 10μM BA and 11.38μM TRIA. The presence of TRIA caused an increase in embryo-producing explants

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