Genetic diversity study of vanillaplanifolia g. jackson, syn. v. fragrans crop grown in Tanzania using molecular technique
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Date
2010
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Publisher
Sokoine Univesirty of Agriculture
Abstract
Vanilla (Vanillaplanifolia G. Jackson, syn. V. fragrans) is native to the tropic-forest
of Mexico. In Tanzania it vanilla has been cultivated in small quantities since in the
1940s in Kagera Region but a decline in coffee prices world-wide in the 1990s
resulted into its increased cultivation as an alternate crop in Kagera and Kilimanjaro
Regions. Vanilla which has a remarkable high price compared to coffee has
consequently spread to Kilimanjaro and Morogoro Regions, and Zanzibar Island.
This study was undertaken to examine the extent of genetic diversity of Vanilla
planifolia cultivars grown in Tanzania using molecular technique.
A total of 126 samples were randomly collected from Bulinda, Bakabuye and Kibona
villages (Kagera Region), Mudio and Kidia villages (Kilimanjaro Region),
Mkunazini and Donge villages (Zanzibar Island). Dellaporta protocol method was
used in deoxyribonucleic acid (DNA) extraction. DNA quantification was done by
comparing band intensity of standard genomic DNA using agarose gel
electrophoresis. For the optimization of Polymerase Chain Reaction (PCR), three
different components; dNTPs, Taq polymerase and MgCh were tested in different
combinations.Ten primers were selected for the Random Amplified Polymorphic
DNA (RAPD) reactions.
These results revealed genetic distances of 0.667, 0.705 and 0.805 for Kagera,
Kilimanjaro and Zanzibar, respectively for intra-population diversity and 1.28 for
inter-population diversity indicating a narrow genetic diversity. Similarly, the
samples used in this study generated 53 bands of which only 27 indicated a low level
polymorphism. Vanilla cultivars from Kilimanjaro and Kagera did not markedly
diverge genetically from those from Zanzibar Island suggesting a narrow genetic
diversity among populations. These results further signify that cultivars used may
have been derived from common parent sources of over several decades. Exchange
of cultivars as planting materials may have played a role in this in phenomenon.
Description
Dissertation
Keywords
Genetic diversity, Molecular technique, Crop grown, Vanillaplanifolia G. Jackson