DSpace Repository :: Browsing by Author "Gichimu, Bernard M."

Browsing by Author "Gichimu, Bernard M."

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Adoption Determinants of Adapted Climate Smart Agriculture Technologies Among Smallholder Farmers in Machakos, Makueni, and Kitui Counties of Kenya
(2021-04) Muriithi, Lydia N.; Onyari, Charles N.; Mogaka, Hezron R.; Gichimu, Bernard M.; Gatumo, Geoffrey N.; Kwena, Kizito
The study examined the adoption determinants of adapted climate smart agriculture (CSA) technologies among smallholder farmers. A multi-stage sampling procedure was used to select a total sample of 384 households. Percentages and regression were employed in data analysis. The results revealed that 47.4% adapted to climate change using integrated farming system, intercropping, crop rotation and agroforestry. Sex (0.9%), education level (9.2%) significantly influenced adoption of the adaptation strategies. Moreover, information sources such as mobile phones (0.9%), and neighbors/friends (0.2%) negatively affected the adaptation strategies. Future policy should aim at creating more awareness through different information sources and provide local extension services.
Agro-morphological characterization of horned melon (Cucumis metuliferus) accessions from selected agro-ecological zones in Kenya
(Australian Journal of crop science, 2020-09) Owino, Marline H.; Gichimu, Bernard M.; Muturi, Phyllis W.
Morphological characterization of genotypes is fundamental in providing information on their genetic status to guide on their conservation and improvement. The objective of this study was to determine agro-morphological diversity within horned melon in Kenya. The study was carried out in two seasons at the University of Embu in Kenya. The study characterized 19 horned melon accessions collected from different agro-ecological zones in Eastern, Central and Western regions in Kenya. The experiment was laid out in a randomized complete block design with three replications. Morphological characterization of the accessions was based on melon descriptors from International Plant Genetic Resources Institute (IPGRI) with slight modifications. Significant differences were observed in all the quantitative traits except the number of branches and main vine length. However, qualitative variations were only observed in fruit shape, rind colour and seed shape. Principle Component Analysis (PCA) showed that fruit weight, main vine length and days to maturity had the highest contribution to the observed diversity. Cluster analysis separated the accessions into seven groups with between classes diversity of 79.20% and within classes diversity of 20.80%. The diversity observed can be exploited by plant breeders for genetic improvement of the crop.
Agro-Morphological Characterization of Kenyan Slender Leaf (Crotalaria brevidens and C. ochroleuca) Accessions
(Hindawi, 2020-04) Mwakha, Fridah A.; Gichimu, Bernard M.; Neondo, ohnstone O.; Kamau, Peter K.; Odari, Eddy O.; Muli, Joshua K.; Budambula, Nancy
Slender leaf (Crotalaria spp) is among the indigenous and underutilized vegetables in Kenya whose production is limited to the Western and Coastal regions of the country. For a long time, this crop has been neglected in terms of research and genetic improvement. *ere is therefore scanty information on its morphological diversity and agronomic performance, hence the need for this study. Field experiments were carried out for two seasons in October to December 2018 and March to May 2019. *e experiments were laid out in Randomized Complete Block Design with 29 accessions and replicated three times. Both qualitative and quantitative data were recorded from the accessions based on the Crotalaria descriptors. Quantitative data were subjected to analysis of variance using XLSTAT Version 2019, and accession means were separated using Student’s Newman Keuls test at 95% level of conﬁdence. Both qualitative and quantitative data were subjected to multivariate cluster analysis, and a dendrogram was constructed using the unweighted pair-group method with arithmetic average. *e principal component analysis was conducted to obtain information on the importance of the characters. Signiﬁcant variation in agro-morphological traits was found within and between the two species. Cluster analysis grouped the accessions into seven major classes with a between-classes diversity of 75.13% and a within-classes diversity of 24.87%. *is study sets the basis for genetic improvement of slender leaf in Kenya since the observed diversity can be exploited in selection for intraspeciﬁc and interspeciﬁc hybridization.
Agronomic Performance of three most Popular Commercial Watermelon Cultivars in Kenya as Compared to one newly introduced cultivar and one local Landrace grown on Dystric Nitisols under Sub- Humid Tropical Conditions
(Asian Research Publishing Network (ARPN)., 2008-11) Gichimu, Bernard M.; Owuor, B. O.; Dida, M. M.
Agronomic performance trial involving five cultivated watermelon accessions available in Kenya was conducted at Maseno University Research Fields for two seasons between year 2007 and 2008. The accessions included three most common commercial watermelon cultivars in Kenya namely ‘Sugarbaby’, ‘Crimson Sweet’ and ‘Charleston Gray’; one newly introduced cultivar from United States namely ‘Yellow Crimson’; and one local landrace (GBK-043014) from Kaka mega district in Western Kenya. The five were evaluated on dystric nitisols under sub-humid conditions of Maseno Division, Nyanza Province in Kenya. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications. Data was collected on agronomic characters including days to emergence, days to flowering, maturity period, and main vine length, number of branches on the main vine and fruit yield (number and weight). The data was subjected to analysis of variance (ANOVA) using SAS version 9.1 and differences declared significant at 5% level. Least Significant Difference (LSD5%) was used to separate the means. Linear correlation was done to compare the relationship between variables. Results demonstrated significant differences in agronomic performance between accessions. ‘Yellow Crimson’ was recommended to Kenyan growers as the best commercial cultivar with agronomic traits which leads to high yields. The landrace was found to contain various desirable agronomic traits which can be selected in future breeding programs. These include long main vine and extensive branching which were found to be highly correlated to yields. It is, however, highly seeded and its taste is unpleasant and should therefore be improved with regard to these traits.
Antimicrobial Activity of Foliar Fertilizer Formulations and their Effect on Ice Nucleation Activity of Pseudomonas syringae Pv. garcae Van Hall; the Causal Agent of Bacterial Blight of Coffee
(Academic Journals, 2011) Mugiira, R. B.; Arama, P. F.; Macharia, J. M.; Gichimu, Bernard M.
This study was carried out with the broad objective of assessing the potential for control of Bacterial Blight of Coffee (BBC) using foliar fertilizer applications to Inhibit Ice Nucleation Activity (INA) of the causative agent (Pseudomonas syringae pv. garcae). Bacteria isolates from four coffee growing areas in Kenya were characterized based on visual, biochemical, physiological and pathogenicity characteristics to distinguish the pathogenic isolates of P. syringae from other phylloplane epiphytic bacteria. Isolates of bacteria from diseased coffee plants were categorised in three groups. Isolates that were pathogenic to coffee and produced typical symptoms of BBC fell under group 1 and were assumed to be of P. syringae pv. garcae. Other isolates that fell under groups 2 and 3 were considered to be saprophytic epiphytes. Four commercially available fertilizer formulations; Bayfolan™, Mboleasafi™, Farmphoska™ and Farmfoliar™ were tested on four pathogenic bacteria isolates collected from the four regions. All formulations significantly (p<0.05) reduced the number of bacterial colony forming units. Bayfolan™ treatment had the highest bacterial growth inhibition potential while Farmfoliar™ was least inhibitive. All the isolates were Ice Nucleation Active (INA+) and all the fertilizer formulations were potentially capable of suppressing the bacterial ice nucleation activity with Farmphoska™ being the most suppressive. Findings presented in this report indicate a potential for the management of BBC using foliar fertilizers to suppress the bacterial INA.
Arabica Coffee Breeding: Challenges Posed by Climate Change
(2015) Gichimu, Bernard M.
Assessment of Four Commercial Watermelon Cultivars and one Local Landrace for Their Response to Naturally Occurring Diseases Pests and Non-Pathogenic Disorders in Sub-Humid Tropical Conditions
(Asian Research Publishing Network (ARPN), 2008-09) Gichimu, Bernard M.; Owuor, B.O; Dida, M. M.
Four commercial watermelon cultivars available in Kenya and one local landrace were evaluated for their susceptibility/resistance to naturally occurring diseases, pests and non-pathogenic disorders. The accessions included three most common commercial watermelon cultivars in Kenya namely ‘Sugarbaby’, ‘Crimson Sweet’ and ‘Charleston Gray’; one newly introduced cultivar from United States namely ‘Yellow Crimson’; and one local landrace (GBK-043014) from Kakamega district in Western Kenya. No inoculation was done because the study targeted naturally occurring diseases, pests and non-pathogenic disorders. Disease rating was done when the most susceptible accession(s) was severely diseased. Data collected was subjected to analysis of variance (ANOVA) using SAS version 9.1 and differences declared significant at 5% level. The SAS procedure PRINCOMP was then used to perform a principle component (PC) analysis using severity scores and accessions plotted on two dimensions using the first two principle components (PC1 and PC2). Results demonstrated significant variation among accessions in susceptibility/resistance to various diseases, pests and non-pathogenic disorders that were observed.
Biochemical Composition Within Coffea arabica cv. Ruiru 11 and Its Relationship With Cup Quality
(Canadian Center of Science and Education, 2014-01-14) Gichimu, Bernard M.; Gichuru, E. K.; Mamati, George E.; Nyende, A.B.
Biochemical composition appears to be influenced by both genetic factors and plant growth conditions. The main objective of this study was to evaluate the biochemical composition of selected Ruiru 11 sibs and its relationship with cup quality. Thirty four (34) Ruiru 11 sibs grown in three different locations in Kenya were used in this study. The experiment was laid out in a Randomized Complete Block Design with three replications. Coffee cherries were picked during the peak harvesting period between 2009 and 2011. The cherries were wet processed and graded into different grades based on size, shape and density. Fifty (50) grams of the dry coffee beans per sib per replication were frozen at -80 ºC before grinding (< 0.5 mm particle size) in liquid nitrogen as specified by the Association of Official Analytical Chemists (AOAC). The samples were packed in small plastic bottles and stored at -80 ºC awaiting extraction of biochemical components. Caffeine, trigonelline and total chlorogenic acids were extracted and purified using classical methods and analysed using High Pressure Liquid Chromatography (HPLC). For the lipids, the sample was subjected to Soxhlet extraction using n-hexane. The study demonstrated the existence of high variation in biochemical composition among Ruiru 11 sibs. Significant correlations were observed between biochemical and cup quality traits indicating that biochemical composition plays a major role in determining the sensory quality of coffee. The growing environment was also found to have an effect on biochemical composition as portrayed by high locational variations.
Characterization of the Volatile Components of Essential Oils of Selected Plants in Kenya
(Hindawi, 2020-12) Mugao, Lydia G.; Gichimu, Bernard M.; Muturi, Phyllis W.; Mukono, Simon T.
Essential oils are secondary metabolites that plants produce for protection from pests and predators, attraction of pollinators, and seed dispersal. )e oils are made up of a mixture of compounds that give a characteristic flavour and odour. Currently, essential oils are receiving great attention in research for their phytochemical and antimicrobial activities. However, there is scanty information on the chemical composition of many plants. )is study provides a detailed analysis of the chemical composition of essential oils of ginger, garlic, tick berry, and Mexican marigold in Kenya. )e essential oils were extracted by steam distillation and analysed by gas chromatography–mass spectrometry. )e study identified a total of 52 different chemical classes from the essential oils of the four different plants that were analysed. )eir percentage composition was also found to vary between the test plants. )e essential oils of Mexican marigold constituted the highest composition of the identified chemical classes at 71.2%, followed by ginger at 55.8%, while both tick berry and garlic oils constituted 53.8% of the total classes identified. Terpenes constituted the highest composition in the essential oils of all the four test plants. Other major chemical classes included esters, ketones, organosulfurs, alkanes, cycloalkanes, steroids, aromatic hydrocarbons, and alkanols. Some of these chemical compounds have been shown to have a huge utility potential in biopesticides, pharmaceutical, and food industries, and hence, their industrial extraction and purification from the essential oils of these plants are recommended.
Coffee Breeding in Kenya: Achievements, Challenges and Current Focus
(2015) Gichimu, Bernard M.
Coffee production in Kenya is seriously constrained by two fungal diseases namely Coffee Berry Disease (CBD) caused by Colletotrichum kahawae (Waller & Bridge) and Coffee Leaf Rust (CLR) caused by Hemileia vastatrix (Berk. and Br.). Growing resistant varieties is believed to be the most cost effective and sustainable means of managing plant diseases. In Kenya considerable success has been made in coffee breeding to improve yields, quality and to manage the two economically important diseases. However, emerging issues such as climate change have brought up new challenges which require to be addressed to ensure sustainability in coffee production. This paper reviews some of the achievements, challenges and future prospects/approaches to develop cost effective and sustainable coffee varieties that enhance yield and quality.
Coffee Breeding in Kenya: Achievements, Gaps and Priorities
(2015) Gichimu, Bernard M.
Coffee Sustainability in Kenya: Role Played by Improved Varieties
(2015) Gichimu, Bernard M.
Coffee production in Kenya has been sinking since 1980s. The condition has been worsened by climate change phenomenon which has brought new production challenges in recent years. The biggest challenge is the changing dynamics of coffee pests and diseases, for example, Coffee Leaf Rust, which has become of a major concern globally. Variety improvement through breeding is believed to be one of the most sustainable ways of reducing production costs and mitigating climate change. Over the years, considerable success has been made in Arabica coffee breeding to improve yields, quality and to manage some biotic and abiotic stresses. Kenya produces mainly Arabica coffee from five commercial cultivars. These include three traditional varieties namely SL28, SL34 and K7, all of which are also susceptible to major coffee diseases, and two improved varieties namely Ruiru 11 and Batian. Owing to the current production challenges and the rising demand of Kenyan coffee in the world market, improved Arabica coffee cultivars with better quality, higher yield potential, resistance to diseases and tolerant to drought are largely replacing traditional varieties on a large scale in Kenya. This paper highlights the foreseeable role of these improved varieties in reversing the tumbling production trend and ensuring coffee sustainability in Kenya.
Combining CBD Resistance with High Yields and Good Cup Quality: Success case in Ruiru 11 Cultivar
(2015) Gichimu, Bernard M.; Gichuru, E. K.; Mamati, G. E.; Nyende, A. B.
Coffea arabica cv. Ruiru 11 is a composite of sixty six (66) F1 hybrid sibs each derived from a cross between a specific female and male population. The pedigree of Ruiru 11 consist of CBD resistance donors, Rume Sudan (R gene), Hibrido De Timor (T or Ck-1 gene), Catimor (T or Ck- 1 gene), K7 (k gene), SL4 and the high yielding, good quality but susceptible cultivars such as N39, SL28, SL34 and Bourbon. Ruiru 11 sibs reportedly present significant variability in terms of resistance to CBD, yields and quality. The objective of this study was to select for CBD resistance, high cherry yields and good quality within Coffea arabica L. cultivar, Ruiru 11. Thirty four hybrid sibs of Ruiru 11 cultivar grown in three different locations in Kenya were used for the study. The experiment was conducted between 2009 and 2011. Ripe cherries were harvested, bulked per replication, weighed and yield data recorded before subjecting them to wet processing, drying, hulling and grading. Beverage quality was determined following the sensory evaluation procedure of Specialty Coffee Association of America (SCAA). Evaluation of CBD resistance was conducted in the laboratory using hypocotyl inoculation method. The study confirmed earlier reports that Ruiru 11 sibs differ in quality aspects, yields and resistance to CBD but some sibs that combine all these desirable traits were identified.
Comparative Antibacterial Effects of Raw Extracts and Essential Oils of Ocimum gratissimum L. against Ralstonia solanacearum (Smith)
(Knowledge Review, 2011) Wagura, A. G.; Kimeju, J. W.; Gichimu, Bernard M.
Raw and processed products of Ocimum gratissimum reportedly contain some antibacterial effects. In this study, raw plant extracts and essential oils derived from leaves of Ocimum gratissimum were screened for their antibacterial properties on Ralstonia solanacearum, the causal agent of bacterial wilt in Irish potato at varying concentrations. The raw extracts were obtained through sequential cold extraction using methanol solvent while the essential oils were extracted through steam distillation. The test products were used at concentrations of 0.4, 0.2, 0.1, 0.05 and 0.025 mg mL_1. Antibacterial tests were done using paper disc diffusion inhibition method and antibacterial activity was determined by measuring the size of inhibition zones. The results showed that the five different concentrations of essential oils and plant extracts exhibited highly significant (p<0.0001) differences on their effects against growth of R. solanacearum. The study confirmed the antibacterial effects of O. gratissimum and further demonstrated that the active compound (s) against Ralstonia solanacearum is (are) concentrated in the essential oils.
Comparing the yield components of three most popular commercial watermelon cultivars in Kenya with one newly introduced cultivar and one landrace
(Academic Journals, 2009-06) Gichimu, Bernard M.; Owuor, B.O; Dida, M. M.
High yield is a major goal for watermelon (Citrullus lanatus) breeders. The objective of this study was to compare the yield components of some watermelon accessions available in Kenya and to identify high yielding accession(s) for recommendation to Kenyan growers and for use in breeding programs. A field trial involving five cultivated watermelon accessions in Kenya namely ‘Sugarbaby’, ‘Crimson Sweet’, ‘Charleston Gray’, ‘Yellow Crimson’; and one local landrace (GBK-043014) from Kakamega district in Western Kenya, was conducted at Maseno University Research Fields between September 2007 and May 2008. The experiment was laid out in a Randomized Complete Block Design with three replications. Data was collected on yield and yield components of the accessions and subjected to analysis of variance using SAS version 9.1. Differences were declared significant at 5% level based on Least Significant Difference. The landrace demonstrated the highest yield potential while ‘Yellow Crimson’ which is a newly introduced commercial cultivar performed much better compared to other commercial cultivars. Selection of desirable traits in these accessions has priority for the future breeding programs. ‘Yellow Crimson’ was also recommended to Kenyan growers as the commercial cultivar with highest yield potential.
Decomposition of the Coffee Value Chain Among Smallholder Farmers in Embu and Kirinyaga Counties in Central Kenya
(UoEm, 2024-10-24) Musau Wambua, Daniel; Ndirangu, Samuel N.; Mogaka, Hezron; Gichimu, Bernard M.
The coffee value chain is lengthy and complex with numerous actors and this exposes the farmers to inherent financial risks. This study sought to decompose the coffee value chain and its dynamics. The study was undertaken in Embu and Kirinyaga counties in Central Kenya and the target population was smallholder coffee farmers. The study used multistage stratified sampling techniques to draw a sample of 385 respondents. Majority (97%) of the sampled farmers were processing and marketing their coffee through cooperative societies. Socioeconomic analysis of these farmers showed that majority were middle-aged, fairly educated and with adequate coffee farming experience but their cherry production was very low averaging 2.3 kgs per tree for 2022/2023 crop year. The cooperative societies were playing key roles in the coffee value chain including farmers’ training, input and credit provision, coffee processing and marketing. There were numerous coffee marketing challenges, including high middlemen involvement, which lowered the coffee prices and reduced the trade volumes. Value adding activities such as roasting, grinding, and packaging were rare and farmers’ involvement in the upstream value chain was minimal. The local demand for the produced coffee was very low with domestic consumption taking only 2% of the output. The multilevel mixed effect model results revealed that value adding and farmer involvement were found to have a significant positive influence on the traded volumes and coffee prices while middlemen involvement had a negative influence. There is need for enhanced value adding and farmers involvement in the upstream value chain as well as strengthening the cooperative societies’ role in coffee marketing for more accountability and increased incomes.
Discrimination of Ruiru 11 Hybrid Sibs based on Raw Coffee Quality
(2015) Gichimu, Bernard M.; Gichuru, E. K.; Mamati, G. E.; Nyende, A. B.
Drought and heat tolerance in coffee: a review
(2012-12) Gichimu, Bernard M.; Cheserek, J.J.
Climatic variability is the main factor responsible for the fluctuations in the coffee yield in the world. The relationships between the climatic parameters and the agricultural production are quite complex, because environmental factors affect the growth and the development of plants under different forms during the phenological phases of the coffee crop. Such environmental factors include reduced rainfall and high temperatures both of which majorly contribute to drought. This paper briefly reviews some of the important aspects of drought and heat tolerance in coffee. It highlights the impacts of draught and high temperatures in coffee production, tolerance mechanisms, necessary interventions, selection challenges and current advances towards development of drought and heat tolerant coffee cultivars.
Drought and heat tolerance in coffee: a review
(International Research Journals, 2012-12) Cheserek, J.J; Gichimu, Bernard M.
Climatic variability is the main factor responsible for the fluctuations in the coffee yield in the world. The relationships between the climatic parameters and the agricultural production are quite complex, because environmental factors affect the growth and the development of plants under different forms during the phenological phases of the coffee crop. Such environmental factors include reduced rainfall and high temperatures both of which majorly contribute to drought. This paper briefly reviews some of the important aspects of drought and heat tolerance in coffee. It highlights the impacts of draught and high temperatures in coffee production, tolerance mechanisms, necessary interventions, selection challenges and current advances towards development of drought and heat tolerant coffee cultivars.
Early Agronomic Performance of Some New and Existing Arabica Coffee Varieties in Kenya
(2015) Gichimu, Bernard M.; Omindi, C. O.; Gichuru, E. K.
The primary goal of plant breeding is to improve yield, quality and disease resistance. However, majority of reported work on coffee breeding primarily concerns agronomical improvement that directly impinges on either coffee quality or yields. The main objective of this study was to compare the agronomic traits of new Arabica coffee varieties with existing commercial cultivars in Kenya. Field recording of cherry yield and disease infection was done during the cropping seasons of 2007 and 2008. Artificial inoculation for both Coffee Berry Disease (CBD) and Coffee Leaf Rust (CLR) were done in respective screening laboratories using Completely Randomized Design (CRD). Significant variations in yield and disease resistance were observed among the genotypes. There were significant negative correlations between disease scores (both CBD and CLR) and cherry yield.

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