School of Agriculture and Biotechnology
Permanent URI for this communityhttp://localhost:4000/handle/20.500.12092/1807
Browse
45 results
Search Results
Item Assessing the contribution of dolichos bean (Lablab purpureus L. (sweet)) to food security in a changing climate in Kenya(2022) Kamotho, Grace N.; Kinyua, Miriam G.; Muasya, Reuben M.Lablab pupureus (L.), is a multipurpose drought tolerant legume which is considered as a minor crop in Kenya, hence, it is underutilized. In Kenya there are few known Lablab genotypes for specific environments. Choice of genotypes to grow is based on colour preference and seed availability, thus low yields are obtained. To assess the status of Lablab production in Kenya, a baseline survey was conducted in Lablab growing localities. A disproportionate stratified sampling was used and a questionnaire was administered to 108 respondents from diverse Lablab growing regions of Kenya. Performance of Lablab genotypes under different environmental conditions was also evaluated. Field trials of forty five (45) accessions of Lablab collected from Rift Valley, Eastern, Coast and Central regions of Kenya were established in three locations with different agro-ecological environments; (Nakuru, Uasin Gishu and Bungoma). The 45 accessions and three environments were factorially combined and replicated three times in a randomized complete block design (RCBD). Results from the survey indicate that most farmers (84.3%) grew Lablab in small acreage of less than 1.0 acre, and only 44.4% of the respondents used the improved Lablab cultivars which were obtained from the Ministry of Agriculture or research stations. Majority (88%) preferred Lablab to common beans and all respondents noted that Lablab fetched more income per unit quantity than common bean. All respondents utilized Lablab dry beans as food. The crop was also utilized as a livestock feed especially during the dry season when no other crops are in the farms by 51.9% of the respondents while 25% used it in conservation agriculture and for soil erosion control. About 20.4% of farmers used the leaves and green pods as vegetables. The study identified accessions that are suitable for different agro ecological zones. In conclusion, Lablab is a crop that is climate resilient and contributes to food security in communities that grow it. It is recommended that dolichos should be promoted in Kenya as a climate change adaptation measure and for enhancing food security.Item Determination of the effect of fermentation on the rate of plant nutrient release from plant tissues.(2022) KAMOTHO, GRACE N.; MUNGA, ZACHARIA M.The use of fermented plant extracts (FPE) as a top dress in crop production is a natural process that can provide plant nutrients and suppress diseases. However, there is scanty information on the use of plant extracts and the bulky of it is not documented. This study aimed at determining the effectiveness of fermentation in extracting plant nutrients from plant tissues for use as top dress in crop production. Materials from Lantana (Lantana camara, L), stinging nettle (Urtica dioica L) and Tithonia (Tithonia diversifolia, G), common plants that are locally available in most agricultural areas were investigated. A complete randomized design (CRD) was used to set up the experiments in the laboratory. Tender shoots and leaves of these plants were fermented in water and the levels of nitrogen, phosphorous and potassium (NPK) contained were measured at intervals of 1, 5, 10, 15, 20 and 25 days. The concentration of lactic acid bacteria (LAB) yeasts and the pH were also determined at each interval. Standard foliar feeds (Agro-Feed and Power Booster) commonly used by farmers were used as control. The results demonstrated that Lantana and stinging nettle were not significantly different in the percentage of N released. Phosphorous was highest in stinging nettle at 5.26%, Tithonia had 5.12% while Lantana had the lowest at 4.48%. However, potassium was highest in Tithonia at 4.38%, stinging nettle had 3.64%, while Lantana had the lowest at 3.63%. There were also high significant differences in concentration of lactic acid bacteria (LAB), Yeast and pH at p<0.05. The findings of the study showed that nutrients can be extracted from plant materials by fermentation although in less quantities as compared to commercial foliar feeds.Item ASSESSMENT OF PRODUCTION CONSTRAINTS AND CONTRIBUTION OF AVOCADO TO FOOD SECURITY AND INCOME IN THE MOUNT KENYA REGION, KENYA(2023) Kamotho, Grace N.; Asiko, Lydiah A.; Kibanyu, James K.; Kinyua, Phares R.; Karaya, Rebecca N.; Muthee, Patrick M.; Mwathi, Zipporah M.ABSTRACT Avocado (Persea americana Mill.) belongs to the family Lauraceae and it is an important crop to rural communities and economies in Kenya. Currently, avocado is grown in several agro ecological zones mainly by small-scale growers (85%) who grow it for subsistence, local markets and export. About 70% of avocado is grown in Central and Eastern region of Kenya. Central region produces 40%, Eastern 28%, Western 13%, Rift Valley 10%, Nyanza 6%, Coast 2% and Nairobi County 1%. The main production areas are Muranga, Kiambu, Thika, Embu, Meru, Taita Hills and Kitale. The aim of this study was to assess the production constraints and contribution of avocado to food security and income in Mount Kenya region. The study population comprised of smallholder avocado farmers. Purposive sampling was done in selecting highest producing sub-counties of avocado in Nyeri, Muranga and Embu counties. Simple random sampling was used to select 40 smallholder farmers from each of the selected sub counties who participated in the survey. Data was collected using a structured questionnaire and analysed using SPSS computer package. Results indicated several constraints in the production of avocado including pests and diseases, lack of quality planting material, poor soils, lack of technical knowledge by avocado farmers and lack of well-structured marketing system. The study identified a gap in value addition of avocado in Kenya. It was also demonstrated that avocado contributes highly to household income and food security. The crop should therefore be accorded priority by policy makers and more research needs to be encouraged especially in the management of pests and diseases. Capacity building to avocado growers should be routinely carried out so as to avoid the many challenges that emanate from lack of technical knowledge. Intervention in value addition of avocado is an aspect that Kenyan county governments need to engage in by investing in cottage industries on avocado processing.Item Assessing the efficacy of wild basil (Ocimum americanum L. (Walp)) in the management of cowpea weevil (Callosobruchus maculatus)(2022-02-28) Mwandikwa, Jacob M.; Kamotho, G. N.Cowpea (Vigna unguiculata (L.) Walp) belongs to the family Fabaceae and is one of the pulses that suffer postharvest losses greatly. The major insect that attacks stored cowpea seed in Kenya is the cowpea weevil (Callosobruchus maculatus). The insect can damage 100% of stored cowpea seeds causing weight loss of up to 60%. Although insecticides are widely available, they have high potential risks to users and also pollute the environment. In drier areas of Kenya where the pest is common, small-scale farmers use botanicals with varying levels of success. This study sought to assess the effectiveness of a locally available botanical, Ocimum americanum, in the management of the cowpea weevil. Different plant parts of O. americanum, the leaves, flowers and whole mature young plants were dried and ground into powder. From each plant part, 0.5, 1.0, 2.0, 4.0 and 8.0 g were used to determine their effectiveness against the weevil in stored cowpea seed. Two controls were used, that is, no protectant and Actellic super dust. For each treatment, 10 g of cowpea seeds were placed in plastic vials containing ten pairs (male and female) cowpea weevil adults. The experiments were laid out in a completely randomized design at the Kenya Agricultural and Livestock Research Organization (KALRO), Nairobi, Entomology Laboratory. Lowest post-harvest weight loss (3.0 g) of cowpea seed and highest mortality (92.5%) of cowpea weevil was recorded when 8 g of leaf powder were used. Since wild basil is a common weed in drier parts of Kenya such as Mbeere, Tharaka-Nithi, Kitui, Makueni and Mwingi, it can be utilized in these areas as a cheap control bioinsecticide for cowpea weevil.Item Investigation of noradrenergic receptor system in anti-nociception using formalin test in the naked mole rat (Heterocephalus glaber).(Elsevier Ltd., 2023-10-23) Mwobobia, R. M.; Kanui, T. I.; Abelson, K. S. P.The naked mole rat (NMR) is a rodent that has gained importance as a biomedical research model for various conditions like hypoxic brain injury, cancer and nociception. This study was designed to investigate possible involvement of the noadrenergic receptor system in antinoception in the NMR, using the alpha-2 adrenergic receptor specific ligands clonidine (agonist) and yohimbine (antagonist) in the formalin test. Formalin test followed 30 min after intraperitoneal administration of ligands or control. A total of 96 naked mole rats were used. A significant reduction in nociceptive behaviours was demonstrated after administration of clonidine in the doses 1,3,10 and 30 μg/kg (n = 8 per group). Doses of clonidine above 30 μg/kg caused loss of motor and proprietion skills exhibited by prostration and failure to turn over when placed on their backs. The antinociception by 3 μg/kg clonidine was reversed by administration of 30 μg/kg of yohimbine. The present study demonstrates that the noradrenergic receptor system is present and involved in formalin test-related antinociceptive mechanisms in the NMR, similar to other mammals. Given the increasing importance of the NMR as a model for pain and nociception, the species may prove useful as an animal model for noradrenergic mechanisms in pain modulation.Item The effects of clonidine and yohimbine in the tail flick and hot plate tests in the naked mole rat (Heterocephalus glaber).(Springer Nature, 2021-05-17) Mwobobia, R. M.; Kanui, T. I.; Abelson, K. S. P.Objective: The naked mole rat (NMR) (Heterocephalus glaber) is increasingly considered an important biomedical research model for various conditions like hypoxic brain injury, cancer and nociception. This study was designed to investigate the effects of clonidine and yohimbine, an alpha-2 (α2) adrenoceptor agonist and antagonist respectively in the tail flick and hot plate tests. Results: A significant difference in tail flick latency was noted between saline control and 30 µg/kg clonidine, which was reduced after administration of 30 µg/kg yohimbine. A significant difference in hot plate latency was also noted between saline control and 30 µg/kg clodinine during the periods 30, 45, 60, 75 and 90 min after administration, and between saline control and 10 µg/kg clonidine during 30 min after administration. The hot plate latency by 30 µg/ kg clonidine was also reduced by 30 µg/kg yohimbine during 30 min after administration. Since the tail-flick and hot plate tests mediate the effects at spinal and supraspinal levels respectively, the present study indicates the presence and involvement of noradrenergic receptors in thermal antinociception at spinal and supraspinal levels of the NMR, similar to what has been found in other mammals.Item In Vitro Bioactivities of Commonly Consumed Cereal, Vegetable, and Legume Seeds as Related to Their Bioactive Components: An Untargeted Metabolomics Approach Using UHPLC–QTOF-MS2.(MDPI, 2023-07-27) Aloo, Simon Okomo; Ofosu, Fred Kwame; Muchiri, Mary Njeri; Vijayalakshmi, Selvakumar; Pyo, Choi-Geun; Oh, Deog-HwanWe conducted a comprehensive evaluation of the antioxidant, anti-obesity, anti-diabetic, and anti-glycation activities associated with the consumption of broccoli, red cabbage, alfalfa, and buckwheat seeds. Additionally, we explored the relationship between these biological activities and Citation: Aloo, S.O.; Ofosu, F.K.; Muchiri, M.N.; Vijayalakshmi, S.; Pyo, C.-G.; Oh, D.-H. In Vitro Bioactivities of Commonly Consumed Cereal, Vegetable, and Legume Seeds as Related to Their Bioactive Components: An Untargeted Metabolomics Approach Using UHPLC–QTOF-MS2. Antioxidants 2023, 12, 1501. https:// doi.org/10.3390/antiox12081501 Academic Editor: Stanley Omaye Received: 25 June 2023 Revised: 23 July 2023 Accepted: 26 July 2023 Published: 27 July 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). the profiles of amino acids, polyphenols, and organic acids identified in the seeds. Our findings demonstrated that red cabbage, broccoli, and buckwheat extracts exhibited significantly higher antioxidant potential compared to the alfalfa extract. Moreover, buckwheat displayed the most signif icant capacity for inhibiting alpha-glucosidase. Remarkably, broccoli and red cabbage demonstrated substantial anti-glycation and lipase inhibitory potentials. We identified the presence of amino acids, polyphenols, and organic acids in the extracts through untargeted metabolomics analysis. Correlation analysis revealed that pyroglutamic acid positively correlated with all the investigated functional properties. Most polyphenols made positive contributions to the functional properties, with the exception of ferulic acid, which displayed a negative correlation with all tested biological activities. Furthermore, gluconic acid and arabinonic acid among the organic acids identified displayed a positive correlation with all the functional properties. These results strongly support the anti-diabetic, anti-obesity, and anti-glycation potential of red cabbage, broccoli, and buckwheat seeds.Item Integrating Cordia Africana Trees on Farms Differentially Improves Soil Properties in Small Holder Farms in Kirinyaga County, Kenya(2023-08-08) Kamau, Miriam; Kinyanjui, Mwangi; Kamiri, HellenTree-based solutions are more efficient in nutrient cycling in farming systems and hence ideally suited for impoverished farmers experiencing food insecurity. Agroforestry trees have a positive effect on soil fertility through litter fall by the canopies compared to that of the adjacent open fields. Field sampling involved selecting mature Cordia africana trees from ten farms and collecting soil samples at varying distances from the tree trunks and at two depths (0-15 and 15-30cm). For each selected farm, soil samples were collected at three sampling points defined by distance from the tree base thus: - 5M (under the tree canopy), 11M (at the edge of the crown), and 30M (from the tree's influence. Laboratory analyses measured concentrations of nitrogen, phosphorus, potassium, calcium, magnesium, and organic carbon. The soil parameters investigated (Nitrogen, Phosphorus, Soil organic carbon, Potassium, and Calcium) were significantly higher in the topsoil than in the subsoil. The horizontal effect of trees with increasing distance from the tree on soil nitrogen, organic carbon, and phosphorus is minimal, the effect being more on vertical distribution (across depth). Differences in nutrient contents in soil nutrient variables between agroforestry and cropped land showed that soil nutrients within the Cordia africana system were higher than those under cultivated land implying that Cordia africana has a positive effect on soil quality. Thus, the study emphasizes the adoption of Cordia africana in agroforestry practices with a view to increase soil fertility and improve crop yields in sustainable farming. There is therefore need for the formulation of appropriate measures of soil management based on the characteristics of the sites.Item Identification of Maize Leaf Diseases Based On AlexNet and ResNet50 Convolutional Neural Networks(2023-08-30) Micheni, Maurice; Birithia, Rael; Mugambi, Cyrus; Too, Boaz; Kinyua, Margaret KMaize crop protection is crucial for global food security, requiring accurate disease identification. In Kenya, farmers rely on subjective visual analysis of symptomatic leaves, which is time-consuming and prone to errors. Computer vision technologies, like deep learning and machine learning, offer promising solutions for disease identification. This study applies Convolutional Neural Networks (CNNs), specifically AlexNet and ResNet-50, to automatically learn image features and enhance speed and accuracy in maize leaf disease identification. A dataset of 3200 digital maize leaf disease images from Embu County is used for training and testing. AlexNet achieved the highest average accuracy of 98.3%, followed by ResNet-50 at 96.6%. The machine learning, support vector machine (SVM) exhibited the lowest average accuracy of 85.5%. These findings highlight the significance of utilizing AlexNet and ResNet-50 in maize leaf disease identification and classification.Item Effect of Intercropping on Potato Bacterial Wilt Disease and Tuber Yield in Kenya(Karatina University, 2023-12-06) MUSAH, S.M.; Birithia, R.K.; Kamiri, H.W.; Kahariri, E.Potato (Solanum tuberosum L.) is a major tuber crop in Kenya, whose productivity is heavily impaired by bacterial wilt disease, caused by Ralstonia solanacearum (Smith). Existing management strategies have not been effective, owing to the diversity and robustness of the pathogen and variation in the host range. The objective of this study was to evaluate the effectiveness of intercropping on the incidence of bacterial wilt and yield of potato in Kenya. A field experiment was conducted in four potato-growing counties, namely; Nyandarua, Nakuru, Bomet and Bungoma in Kenya. Treatments included intercroping with spring onion (Allium fistulosum L.); garden pea (Pisum sativum L.); and cabbage (Brassica oleracea var. capitata L.). Treatments also included a pure stand of potato as the control. Generally, intercropping had a significant suppressive effect (P<0.05) on the incidence and severity of bacterial wilt disease. Intercropping potato with spring onion, in particular, had the highest disease suppressive effect, followed by intercropping potato with cabbage; and lastly by potato with garden pea. Accordingly, potato-onion intercrop recorded the highest potato tuber yield (12.9 t ha-1), while the potato pure stand recorded the lowest tuber yield (7.9 t ha-1). Bacterial wilt disease incidence positively correlated with disease severity (r = 0.931; P<0.05). In contrast, the disease incidence and severity negatively correlated with tuber yield. In terms of Land Equivalent Ratio (LER), the highest value (1.64) was with potato-onion intercrop; and the lowest (1.35) with the potato-garden pea intercrop.