Genetic diversity of cultivated coffee (coffee arabical) in Tanzania
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Date
2014
Authors
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Journal ISSN
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Publisher
Sokoine University of Agriculture
Abstract
Ten new genotypes and eighteen old cultivars of Cojjea arabica from different areas in
Tanzania as well as two reference cultivars (N 39 and KP 423) were characterized
morphologically and using coffee DNA microsatellite (SSR) markers. The objective of
this study was to determine the level of morphological and molecular variation within and
between new and existing coffee varieties in Tanzania. The Morphological
characterization was done using 25 character coffee descriptors (IPGRL 1996), while the
molecular characterization 30 SSR markers were used. Both quantitative and qualitative
morphological traits were recorded and the binary data were subjected to cluster and
principal component analysis. Morphological variation among the genotypes was less
than 25%. Four main groups were formed and improved hybrids cultivars except N39-1
were clustered in one group with the traditional cultivars N39 and KP423. Genotypes
from Cojfee arabica growing regions were clustered in separate groups. There was very
little morphological variation within the varieties. Principal component analysis revealed
clear separation of genotypes from Kilimanjaro and Arusha from the other group.
The hybrid N 39 was grouped with the old cultivars from different regions. The first two
principal components accounted fbr a cunuilalive variance of 60%. The study showed
narrow genetic base of cultivated C. arabica in Tanzania. Furthermore, total alleles
detected 82% were polymorphic and specific. In the cluster analysis, the hybrid varieties
clearly separated from the other cultivated cultivars fiom different regions as well as the
control N 39 and KP 423 based on SSR. The study demonstrated low morphological
variation and hence low genetic variation among the varieties and emphasized the need to
broaden the genetic base of Arabica coflee in Tanzania. In addition, die study
demonstrated low molecular variation within the varieties indicative of high genetic
consistency.
Description
Dissertation
Keywords
Coffee arabica genotype, Coffee-Tanzania, Coffee evaluation