Department of Plant Science
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Item PREVALENCE OF BEAN ROOT ROT PATHOGENS IN THARAKA NITHI COUNTY, KENYA(Journal of Science and Technology,, 2024-12-20) Apiud M. Araka; Moses M. Muraya; Eric K. Kuria; ; ;Kenya is among the top common bean producing countries globally with an annual production of 0.76 million tonnes worth Ksh. 60 billion. However, its production faces several biotic and abiotic challenges. Among these challenges is the root rot disease, which causes an estimated yield loss of 70% every year. The disease is caused by several soilborne pathogens, making it difficult to control through use of cultural practices, chemicals and development of tolerant varieties. This study was carried out in five bean growing agroecological zones in Tharaka Nithi County, Kenya during the long rains season (March to April) of 2023. The aim of the study was to determine the prevalence of the root rot disease pathogens in different agroecological zones in the county. A descriptive survey design was used to collect data on prevalence of the disease in farms. Analysis of variance was used to determine if there were significant differences in prevalence between different agro-ecological zones. Further the significant means were separated using Least Significant Difference at α = 0.05. The findings of the study showed that bean root rot disease was caused by four main soilborne microorganisms including Fusarium, Macrophomina, Pythium and Rhizoctonia spp which occurred in all agroecological zones of the county. The highest disease prevalence (37.58%) was in AEZ UM3 followed by LM4 (34.17%), LM5 (20.63%), UM2 (18.2%) and UM1 (16.76%) respectively. Additionally, the prevalence of the disease pathogens varied significantly (p < 0.05) across the agroecological zones in the county. Therefore, appropriate measures should be employed to control and reduce yield loss associated with the disease.Item Effect of Cattle Manure Vermicompost on Bean Root Rot Pathogens in The Greenhouse Pot Experiments(Journal of Science and Technology,, 2025-10-03) A. M. Araka; M. M. Muraya; E. K. Kuria; ; ;The root rot disease in beans is one of the limiting factors affecting common bean production worldwide. Under favourable conditions, the disease can cause yield losses of up to 75%. Control and management strategies of the disease mostly involve the use of fungicides. However, this method is expensive for the majority of farmers, and excessive use of fungicides is detrimental to the environment. Therefore, researchers extensively explore eco-friendly alternatives to minimise adverse effects and the use of synthetic fungicides. One of such options is the use of cattle manure vermicompost. The study was conducted from March to April 2023 at the research greenhouse of the department of plant science of the faculty of agriculture of Chuka University, Kenya. The objective of the study was to determine the effect of cattle manure vermicompost on the severity of root rot in beans in the greenhouse pot experiments. An experimental research design was used to collect data on the effect of cattle manure vermicompost on the severity of pathogens causing bean root rot in the greenhouse pot experiments. Analysis of variance was used to determine if there was a significant effect of cattle manure vermicompost on the severity of root rot pathogens in beans in the greenhouse pot experiments. The Least Significant Difference was used for separation of significant means at α = 0.05. The study findings showed that cattle manure vermicompost significantly reduced the severity of root rot disease in beans during greenhouse pot experiments (p < 0.05). The maximum suppression effect of the disease was observed at a 40% amendment of cattle manure vermicompost, with the lowest disease severity index between 0 and 3.3. Therefore, the management of root rot disease in bean production should incorporate cattle manure vermicompostItem Factors Influencing Selection and production of Common Bean Cultivars in medium Potential Agro Ecological Zone of Imenti South Sub-County, Kenya(International Journal of Research and Innovation in Social Science, 2024-11-20) Ian M. Kirimi1; Moses M. Muraya; Shelmith W. Munyiri; James K. Kiramana; ; ;Item Heavy Metal Phytoremediation Potential of Wild Plant Species Naturally Growing on Dumpsite, Kenya(2024-12-14) Orao LA; Muraya MM; Ombaka CO; ; ;Soils form an essential part of life and the main sink of pollutants. Intense industrial and anthropogenic activities have led to serious environmental threats, resulting in increased heavy metal concentration in soils and, consequently, a phytotoxicity effect on plants. Phytoremediation can offer effective and eco-friendly remedies for polluted sites. This study characterized the diversity of various plants that spontaneously grow in a dumpsite and scrutinized their phytoremediation potential. The plants evaluated for phytoremediation potential were Ricinus communis, Parthenium hysterophorus, Cassia didymobotrya, and Datura stramonium. The location of the research was Kang’oki dumpsite, Kenya. Species diversity was studied using quadrat sampling thrown randomly throughout the dump site. The bioaccumulation factor (BF) and the translocation factor (TF) were calculated to determine the accumulation and mobility of the heavy metals in the plants. To determine the ability of the plants to remove, accumulate, and mobilize the selected heavy metals, soil and plant sampling was conducted within the 14 sampling sites. The samples were acid-digested, and concentrations of Pb, Zn, Cu, and Cd were analyzed using Atomic Absorption spectrophotometry. Data obtained was subjected to statistical analysis using SAS version 94. Shannon-Weaver diversity index (H’) was used for species diversity. An H’ of 0.94 and species evenness of 0.45 was found showing a high species diversity on the dumpsite. Cadmium concentration in soil samples ranged from ND to 1.63 mg/kg of soils and 0.4418 to 0.6939 mg/kg of plant tissues. Nickel concentration ranged from 7.9 to 36.33 mg/kg in soils and 9.31 to 11.38 mg/kg in plant tissue, respectively. Copper was found between 3.41 to 121.18 mg/kg of soils and 3.74 to 10.89 mg/kg of plant tissues, respectively. Lead in soils ranged from 13.25 to 8.013 mg/kg of soils and 11.48 to 13.89 of plant tissues. Leaves accumulated significantly (p < 0.05) higher amounts of heavy metals than roots and stems. The leaves and stem of Datura stramonium showed the highest concentration of cadmium and copper, while its stem showed the maximum concentration of Nickel and lead. Datura stramonium showed BCF and TF >1; hence, it can be used for phytoextraction of cadmium. All plants showed TF>1; hence, these plants can be used as hyperaccumulators.Item A Comparative Study of Caffeine Levels in Coffee and Cocoa in Kenyan Supermarkets and Shops(Pan-African Journal of Health and Environmental Science, 2024-12-16) Alex Muthengi; Silas Njiru; Juster Mungiria; ; ;Background: Caffeine is an alkaloid belonging to the methylxanthine family. An overdose of caffeine causes the following side effects: restlessness, nervousness, excitement, insomnia, flushed face, diuresis, gastrointestinal disturbances, muscle twitching, rambling flow of thought and speech, and tachycardia or cardiac arrhythmia. This study aimed to determine the caffeine levels of various brands of coffee and cocoa and enlighten people on the safe and healthy consumption of the two products. Methods: Different brands of coffee and cocoa products were randomly sampled and purchased from supermarkets and shops in Nairobi, Kenya. Five samples of coffee and four brands of cocoa were purchased from a supermarket and taken to the laboratory for analysis. Caffeine was extracted, and quantitative analysis was done using High Performance Liquid Chromatography (HPLC). Results: The study found that coffee has a higher concentration of caffeine than cocoa. Coffee Brand A recorded the lowest level of caffeine with 30.9845 µ g/g, while Coffee Brand C recorded the highest level of caffeine with 426.9639 µ g/g. Among the Cocoa brands, Cocoa Brand B recorded the lowest level of caffeine (2.6367 µg/g), while Cocoa Brand C recorded the highest level of caffeine at 19.03 µ g/g. Conclusion: Therefore, there is a need to reduce coffee consumption per day because caffeine overdose can cause high blood pressure and other illnesses. Cocoa is recommended for consumption since it contains less caffeine per serving.Item Optimization of Groundnuts (Archis hypogeal) Yield through Response Surface Methodology(Asian Journal of Probability and Statistics, 2024-04-16) Dennis Kiprotich; Dennis K. Muriithi; Martin K. Njogu; ; ;Groundnut production faces several constraints, including poor soil fertility, small land sizes, and inappropriate agricultural techniques. The study aimed to optimize groundnut (Archis hypogeal) yield using response surface methodology (RSM). It explored the use of CCD and RSM to determine the optimal application of rabbit, poultry, and sheep manure for maximum yield, a method not previously applied in groundnut production. The study was conducted at the Chuka University Teaching and Training Farm, Kairani. The experimental design was developed using Central Composite Design (CCD), with 20 experimental runs derived from 23 full factorial designs with six axial points and six center points. Data was collected on the weight of the groundnuts yield harvested in each experimental plot measured by use of aweighing scale. Response Surface Methodology techniques was adopted for data analysis in R-statistical software and R studio programing language. The study findings indicated that organic manures had a significant effect (P < 0.05) on the yield of groundnuts crop. The study revealed that application of 13.6097 t ha-1, 10.582 t ha-1 and 11.0814 t ha-1 of poultry, rabbit and sheep manure respectively are the optimum levels that would lead to maximum weight of groundnuts in the study area. The finding of this study could have an economic benefit to farmers in the study area which aligns with broader national goals of poverty reduction, rural development, and economic growth. This study recommended that farmers should adopt organic farming practices to reduce reliance on chemical fertilizers, improve soil health, and contribute to environmental sustainability.Item Analysis of Technical Efficiency on Orange Fleshed Sweet Potatoes Production Among the Smallholder Farmers in Migori County Kenya(Published by Science Publishing Group., 2024-08-12) Lawrence Otieno Jabuya; Shelmith Wanja Munyiri; Martin Kagiki Njogu; ; ;Sweet potatoes (Ipomea batatas L.), particularly the orange fleshed variety, have become increasingly popular due to their ability to thrive in various environmental conditions with minimal inputs. Orange fleshed sweet potatoes (OFSPs) show potential for productivity, yet smallholder farmers in Kenya still struggle to maximize their yields. The factors influencing OFSP production efficiency among these farmers in Western Kenya have not been thoroughly examined. This study evaluated the technical efficiency of OFSP production among smallholder farmers in Migori County. Using a descriptive research design, a sample of 225 OFSP farmers was randomly selected by a cluster sampling technique. Data was collected through a structured questionnaire on inputs and selected socio-economic factors. The data was analyzed using the frontier stochastic model in STATA. Smallholder farmers estimated mean technical efficiency was 77.82% significant variables were; size of the land, availability of planting vines, access to hired labour, gender of the household decision maker, farming experience, household size, land ownership status, participation in training programs and extension services, and proximity to markets, indicating a need to improve OFSP production by 22.18%. These findings suggest that to reduce inefficiencies among smallholder OFSP farmers, targeted training programs are needed to enhance farmers' agronomic knowledge specific to OFSP production. Further, policy interventions should prioritize the provision of extension services to support and improve the performance of OFSP smallholder farmers.Item HORT 323: INTRODUCTION TO GREENHOUSE MANAGEMENT(Chuka University, 2023-04-13) Chuka University; ; ;Item HORT 333: GENERAL VEGETABLE PRODUCTION(Chuka University, 2023-04-13) Chuka University; ; ;Item Analysis of Technical Efficiency on Orange Fleshed Sweet Potatoes Production Among the Smallholder Farmers in Migori County Kenya(Agriculture, Forestry and Fisheries, 2024-08-07) Lawrence Otieno Jabuya; Shelmith Wanja Munyiri; Martin Kagiki Njogu; ; ;Sweet potatoes (Ipomea batatas L.), particularly the orange fleshed variety, have become increasingly popular due to their ability to thrive in various environmental conditions with minimal inputs. Orange fleshed sweet potatoes (OFSPs) show potential for productivity, yet smallholder farmers in Kenya still struggle to maximize their yields. The factors influencing OFSP production efficiency among these farmers in Western Kenya have not been thoroughly examined. This study evaluated the technical efficiency of OFSP production among smallholder farmers in Migori County. Using a descriptive research design, a sample of 225 OFSP farmers was randomly selected by a cluster sampling technique. Data was collected through a structured questionnaire on inputs and selected socio-economic factors. The data was analyzed using the frontier stochastic model in STATA. Smallholder farmers estimated mean technical efficiency was 77.82% significant variables were; size of the land, availability of planting vines, access to hired labour, gender of the household decision maker, farming experience, household size, land ownership status, participation in training programs and extension services, and proximity to markets, indicating a need to improve OFSP production by 22.18%. These findings suggest that to reduce inefficiencies among smallholder OFSP farmers, targeted training programs are needed to enhance farmers' agronomic knowledge specific to OFSP production. Further, policy interventions should prioritize the provision of extension services to support and improve the performance of OFSP smallholder farmers.Item HORT 421: HORTICULTURAL SEED PRODUCTION(Chuka University, 2024-12-16) Chuka University; ; ;Item HORT 421: HORTICULTURAL SEED PRODUCTION(Chuka University, 2024-12-16) Chuka University; ; ;Item HORT 421: HORTICULTURAL SEED PRODUCTION(Chuka University, 2024-12-16) Chuka University; ; ;Item HORT 421: HORTICULTURAL SEED PRODUCTION(Chuka University, 2024-12-16) Chuka University; ; ;Item HORT 421: HORTICULTURAL SEED PRODUCTION(Chuka University, 2024-12-16) Chuka University; ; ;Item HORT 361: FLORICULTURE 1 (MAJOR CUT FLOWERS)(Chuka University, 2024-12-16) Chuka University; ; ;Item HORT 333: GENERAL VEGETABLE PRODUCTION(Chuka University, 2024-12-16) Chuka University; ; ;Item HORT 212: PLANT IDENTIFICATION(Chuka University, 2024-12-16) Chuka University; ; ;Item Genetic and Phenotypic Diversity of Selected Kenyan Mung Bean (Vigna Radiata L. Wilckzek) Genotypes.(Springer Open., 2021) Mwangi, J. W.; Piero, N. M.; Kariuki, M. P.; Okoth, O. R.Background: Mung bean is a pulse crop principally grown in the tropic and subtropic parts of the world for its nutrient-rich seeds. Seven mung beans accessions from Eastern Kenya were evaluated using thirteen phenotypic traits. In addition, 10 SSR markers were used to determine their genetic diversity and population structure. This aimed at enhancing germplasm utilization for subsequent mung bean breeding programs. Results: Analysis of variance for most of the phenology traits showed significant variation, with the yield traits recording the highest. The first three principal components (PC) explained 83.4% of the overall phenotypic variation, with the highest (PC1) being due to variation of majority of the traits studied such as pod length, plant height, and seeds per pod. The dendogram revealed that the improved genotypes had common ancestry with the local landraces. The seven mung beans were also genotyped using 10 microsatellite markers, eight of which showed clear and consistent amplification profiles with scorable polymorphisms in all the studied genotypes. Genetic diversity, allele number, and polymorphic information content (PIC) were determined using powermarker (version 3.25) and phylogenetic tree constructed using DARWIN version 6.0.12. Analysis of molecular variance (AMOVA) was calculated using GenALEx version 6.5. A total of 23 alleles were detected from the seven genotypes on all the chromosomes studied with an average of 2.875 across the loci. The PIC values ranged from 0.1224 (CEDG056) to 0.5918 (CEDG092) with a mean of 0.3724. Among the markers, CEDG092 was highly informative while the rest were reasonably informative except CEDG056, which was less informative. Gene diversity ranged from 0.1836 (CEDG050) to 0.5102 (CDED088) with an average of 0.3534. The Jaccards dissimilarity matrix indicated that genotypes VC614850 and N26 had the highest level of dissimilarity while VC637245 and N26 had lowest dissimilarity index. The phylogenetic tree grouped the genotypes into three clusters as revealed by population structure analysis (K = 3), with cluster III having one unique genotype (VC6137B) only. AMOVA indicated that the highest variation (99%) was between individual genotype. In addition, marker traits association analysis revealed 18 significant associations (P < 0.05). Conclusion: These findings indicate sufficient variation among the studied genotypes that can be considered for germplasm breeding programs.Item Stubborn Disease of Citrus Caused by Spiroplasma Citri: A Short Note.(EScience Press, 2021) Kiptoo, J. J.; Kiptoo, G. J.; Chemoiwa, E.; Pixley, K.; Abbas, A.; Usman, H. M.; Mubeen, M.Citrus fruit is considered a very nutritious and delicious diet. Citrus consists of lemon, oranges, mandarin, and grapefruit which have economic value in the world. Significant losses occur in citrus due to numerous diseases. Among various diseases, citrus trees are seriously affected by a phytopathogenic mollicute Spiroplasma citri which causes stubborn disease. S. citri is transovarially transmitted by several leafhopper species. Symptoms include smaller and cupped leaves, small size, crook fruits with aborted seeds. Moreover, irregularity on the fruits such as different sizes, shapes, and typically lighter, smaller fruits than its healthy counterpart has also been observed. The affected fruits often drop before maturity. The color inversion is often seen with the stylar end remaining green and the peduncle end showing color. Various molecular and biochemical tests are conducted to identify S. citri. Under in-vitro conditions, S. citri grows on SP4 media where a fried egg-like shaped colony is observed. Keeping the importance of the stubborn citrus disease, the present short note briefly described the symptomology, detection, transmission, and management.