Browsing by Author "Muhoho, SM."

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    Evaluation of beverage quality and green bean physical characteristics of selected Arabica coffee genotypes in Kenya
    (Academic Journals, 2009-10) Gichimu, Bernard M.; Kathurima, CW.; Kenji, GM.; Muhoho, SM.; Boulanger, R.
    Physical characteristics of green coffee bean have been reported to affect beverage quality to some extent. The objective of this study was to assess the beverage quality and green bean physical characteristics of forty two arabica coffee genotypes and to determine the relationship between the two attributes. Green bean physical characteristics were assesed through actual measurements, grading and weighing while beverage quality was determined by a panel of seven judges using the prescribed sensory evaluation procedures. Sensory data was used to calculate diversity in beverage quality among genotypes and to construct a dendrogram using the unweighted pair-group method with arithmetic average. Data were also subjected to analysis of variance and differences declared significant at 5% level based on Duncan’s Multiple Range Test. Linear correlation was done to compare the relationship between variables. Cluster analysis results demonstrated 0 - 47% diversity in beverage quality among genotypes. There was close similarity among coffee tasters in ranking various beverage quality characteristics of the cultivars indicating that the panel was reliable in assessment of beverage quality. All sensory variables evaluated were positively and significantly correlated. However, correlations between the sensory variables and green bean physical characteristics were non-significant.
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    Genetic diversity among commercial coffee varieties, advanced selections and museum collections in Kenya using molecular markers
    (Academic Journals, 2012-02) Gichimu, Bernard M.; Kathurima, CW.; Kenji, GM.; Muhoho, SM.; Boulanger, R.; Gichuru, E. K.
    Molecular markers have effectively been applied to study genetic diversity and as markers of particular traits. This study assessed the diversity of twenty four (24) coffee genotypes using 10 Random Amplified Polymorphic DNA (RAPD) primers and 2 microsatellites (M24 and Sat 235). A total of 35 polymorphic bands were generated by the RAPD primers. The bands were scored for presence (1) and absence (0) of amplified products. The data was subjected to cluster analysis using R statistical software and a dendrogram constructed using Unweighted Pair Group Method with Arithmetic Average (UPGMA). The genotypes separated into three main clusters. C. eugenioides clustered alone in the first cluster while un-introgressed Arabica genotypes dominated the second cluster. The third cluster comprised of Coffea canephora (Robusta) and introgressed genotypes, Ruiru 11, Hibrido de Timor and Catimor. Robusta and C. eugenioides were the most distantly related and generated most of the diversity observed. The similarities observed among un-introgressed Arabica genotypes attest to the narrow genetic diversity within Coffea arabica. The divergence observed among introgressed genotypes could be utilized in future breeding programmes.