Biological Science
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Item Implication for in situ conservation of indigenous species with special reference to wild Coffea arabica L. population in Mount Marsabit Forest, Kenya(Universidad Autónoma de Yucatán (UADY), 2011) Eunice W. Githae; Charles K. K. Gachene; David W. OdeeMt. Marsabit forest is the only forest in Kenya where Coffea arabica L. (Rubiaceae) occurs naturally in wild populations. This forest however is highly fragmented and decreasing at a rapid rate due to anthropogenic activities. This study assesses the diversity and structure of species of conservation concern with reference to wild coffee as basis for management, conservation and use of wild genetic resources in Kenya. A botanical inventory and diversity study identified 52 species of trees and shrubs, 12 species of herbs and six species of climbers and lianas were recorded and belonged to 35 families and 64 genera. Rubiaceae (Coffee family) was the richest family with nine species followed by Euphorbiaceae with six species. Rinorea convallarioides (Bak.f.) Eyles ssp. marsabitensis Grey-Wilson (Violaceae), an endemic species, and Drypetes gerrardii Hutch. (Euphorbiaceae), were the two most important species, accounting for more than third of the combined importance value. Coffea arabica was dominant in the forest undergrowth with a higher density occurring in the open patches where it was competing with other shrubs and small trees in the undergrowth. The success and future management and conservation strategy of this forest depend on how to conserve the forest genetic resources especially of this wild species.Item Influence of Socio-economic Factors on Prevalence of Ochratoxin A in Dry Coffee Cherry in Tharaka Nithi County, Kenya(Kenya Horticultural Society, 2024-12) Tabitha K. Gitonga; Eunice W. Githae; Moses M. Muraya; Olivia A. NjiriCoffee is a vital cash crop worldwide, contributing significantly to foreign exchange earnings and offering potential health benefits. However, concerns over contamination with mycotoxins, particularly Ochratoxin A (OTA), have grown due to its serious health risks. This study investigated the influence of socioeconomic factors on the prevalence of OTA in dry Coffee Cherry from Tharaka Nithi County, Kenya. A cluster random sampling method was used to collect the dry coffee cherry samples and survey data from 143 farmers across three agroecological zones, employing a semi-structured questionnaire. Pathogens were isolated on Potato Dextrose Agar (PDA) media and OTA production assessed according to the International Commission on Microbiological Safety for Foods. Data was analysed using the SPSS version 28 and SAS version 9.4. The study found out that socio-economic factors significantly (p < 0.05) influenced coffee farming practices and prevalence of OTA. Ochratoxin A prevalence was strongly associated with agro-ecological zones, farm size, and altitude. Larger farms and lower altitudes were linked to higher OTA risks. Gender, farm size and coffee variety also influenced OTA contamination levels. The study revealed that 88.3% of coffee farmers recognized mold in dry coffee cherries, yet 22.8% consuming moldy cherries, with 64.1% unaware of the health risks. Additionally, 87.6% of farmers identified poor drying and storage practices as key contributors to OTA contamination. Key indicators of contamination included discoloration, moldy smell, and moldiness with wetness. Roasting practices varied, with 35.1% roasting dried cherries after fermentation. The study highlights significant socioeconomic factors influencing OTA contamination in coffee. To mitigate risks, it is recommended to improve farmers' awareness of mold-related health risks and implement targeted interventions in high-risk areas to reduce OTA prevalence.Item Ethnobotanical and vegetation survey of Kiango’mbe and Kianjiru Hill Forests in Embu County, Kenya(International Scholars Journals, 2015-11-10) Waiganjo, B. W.; Githae, E. W.; Warui, C. M.; Opiyo, E. A.Ethnobotanical study and vegetation survey was carried out in Kiang’ombe and Kianjiru hill forests of Embu County to evaluate the indigenous knowledge relevant to malaria cause, diagnosis, treatment and prevention as well as to establish the hills’ medicinal plants species diversity. Semi-structured questionnaires were used to gather ethnobotanical information while trees with diameter at breast height ≥5 cm, shrubs and herbs were sampled by use of 20×20, 5×5 and 1×1 m plots respectively. Malaria symptoms mentioned in this study were in concurrent with the widely acceptable ones and they included: headache, vomiting, loss of appetite, joint pains and fever. Mosquito was recognized as the main malaria vector. Fifty six species belonging to 31 families were documented from the ethnobotanical study. Achyrothalamus marginatus, Dombeya rotundifolia, Monanthotaxis schweinfurthii and Premna resinosa were documented for the first time in this study indicating high endemism. Barks, roots, trees and shrubs were the most commonly harvested parts and growth forms respectively. Charcoal burning, timber harvesting, grazing and forest fires were observed. Kianjiru had significantly (P≤0.001) higher diversity index (H’=2.92) than Kiango’mbe (H’=2.63). The two hill forests are major sources of medicinal plants and therefore the need to conserve them.Item Effects of Agricultural Nutrients Influx on Water Quality in Thiba River Basin, a Sub-catchment of Tana River Basin in Kirinyaga County, Kenya(East African Nature and Science Organization, 2022-04-21) Joseph Mugendi Njue; Adiel Micheni Magana; Eunice Wamuyu GithaeExcessive enrichment of waters with nutrients and the associated adverse biological effects leads to eutrophication, which is one of the major environmental problems across the world. Various studies have revealed the overuse of inorganic fertilizers to increase agricultural productivity in Kenya contributes to pollution of water bodies. In order to meet increasing demand for clean water, sustainable use and conservation of available water resources is therefore paramount. This study was done to find out effects of agricultural nutrient pollution in Thiba River, a sub-catchment of Tana River Basin, located in Kirinyaga County, Kenya. The study area was divided into four distinct agroecological zones based on different anthropogenic activities. Ecological survey design was used in the study. Sampling was done during the wet and dry season. Water samples were analysed for temperature, transparency, pH, electrical conductivity (EC), salinity, total dissolved solids (TDS), dissolved oxygen (DO), biological oxygen demand (BOD), phosphates, nitrates, nitrites, ammonia, and toxic microalgae. All parameters showed both spatial and temporal variations with statistically significant differences (p˂0.01). Temperature of the river ranged from 14.57 0C to 28.08 0C due to climatic changes along the agroecological zones. The pH ranged from 7.02 to 8.51. The DO values decreased from the highlands to lowland within the range of 9.00 mg/l at the reference site to 5.43 mg/l at the most polluted site. EC ranged from 20.54 μScm-1 at the reference site during the wet season to 251.2 μScm-1 at the rice irrigation scheme site during dry season. The TDS ranged from 16.9 ppm at the reference site to 167.05 ppm at the most polluted site. Salinity also had a high variation with a range of 0.01 ppt at the reference site to 0.07 ppt at the most polluted site. The highest values of BOD (3.49 mg/l) were recorded at the rice irrigation scheme during the wet season and the lowest (0.22 mg/l) at the forest edge reference site.Item Long-distance gene flow in Acacia senegal: Hope for disturbed and fragmented populations(Wiley, 2023-06-29) Stephen F. Omondi; Eunice W. Githae; Damase P. KhasaEven though pollen and seed dispersals are some of the important factors that determine tree species survival across landscapes, gene dispersal data of important tropical dryland tree species such as Acacia senegal that are undergoing various population disturbances remain scarce. Understanding patterns of gene dispersal in these ecosystems is important for conservation, landscape restoration and tree improvement. We investigated pollen and seed mediated gene flow in two A. senegal populations of contrasting state (less disturbed and heavily disturbed) using nine microsatellites and 128 genotyping-by- sequencing single nucleotide polymorphism (SNPs) multilocus genotypes of two growth stages (juvenile and adult trees) and their spatial locations. We performed parentage assignments using likelihood approach and undertook spatial genetic structure (SGS) analyses for the two growth stages through correlation among kinship coefficients and geographical distances between pair of individuals. The SNPs showed higher resolving power and assignment rates than microsatellites; however, a combination of the two marker-types improved the assignment rate and provided robust parentage assessments. We found evidence of long-distance (up to 210 m) pollination events for both populations; however, the majority of seed dispersal was found closer to the putative maternal parent. On average, parentage analysis showed high amounts of pollen (40%) and seed (20%) immigration in both populations. Significant positive SGS was found only for the adult cohorts in the less disturbed population for distance classes 20 and 40 m, indicating historical short-distance seed dispersals. Our results suggest long-distance gene flow within the species and we recommend conservation of remnant and isolated populations or individual trees to promote genetic connectivity.Item Soil physicochemical properties under Acacia senegal varieties in the dryland areas of Kenya(Academic Journals, 2011-08) Eunice W. Githae; Charles K. K. Gachene; Jesse T. NjokaAcacia senegal is a multipurpose drought-tolerant tree or shrub legume and is commonly used in agroforestry systems in sub-Saharan Africa for gum arabic production and soil fertility improvement. Despite its wide distribution in Kenya, there has not been exhaustive evaluation on the effects of the extant varieties (kerensis, leiorhachis and senegal) on soil properties under their canopies for sustainable utilization of the species. Three sites in the drylands of Kenya representing the three varieties were selected for assessment. Soil samples were collected under tree canopies at a depth of 0 to 25 cm and were compared with the soils from the open canopies. There were significant differences in soil physicochemical properties among the three varieties (P<0.05 and P< 0.01). Soil nutrients under the canopies were higher than in the open canopies mainly due to effects of litter accumulation. The three varieties have beneficial effects on soil nutrient status in their natural ecosystems and would most likely improve crop productivity in agroforestry systems as well as enhance herbage productivity in the rangelands. The varieties growing under different soil types may have an effect on their gum Arabic production and quality.Item Prickly Pear Cactus Invasion: A Major Threat to Biodiversity and Food Security in the Drylands of Kenya(AgriFoSe2030, 2018) Githae E. W.Item Prevalence of Green Gram Fungal Diseases in the Eastern Part of Kenya(East African Agricultural and Forestry Journal (EAAFJ), 2021) T. K. Gitonga; E. W. GithaeGreen gram (Vigna radiata L.), also known as Mung bean, is an annual legume crop that is grown all over the world. Green gram yield in the arid and semi-arid lands of Kenya is still low due to various factors including plant diseases and poor soils. The objective of this study was to evaluate prevalence of green gram fungal diseases and the effects of soil factors on their occurrence in Tharaka-Nithi and Kitui Counties in Kenya. The study was conducted in Kitui Central and Kyangwithya wards in Kitui County, and Mukothima and Nkondi wards in Tharaka-Nithi County. Household surveys were conducted using a semi-structured questionnaire. Farm surveys were carried out using transects to evaluate disease incidence and severity. Symptomatic green gram samples were collected for isolation of pathogens. Isolates were identified based on morphological features and cultural characteristics. Soil samples were collected from farms and analyzed for physicochemical properties. Eight fungal diseases with diverse morphological and cultural characteristics were identified. The diseases were Downy mildew, Powdery mildew, Cercospora leaf spot, Macrophomina rot, Anthracnose, Late blight, Corynespora spot and Angular spot. Disease severity and incidences ranged from 6.13 to 32.2% and 16.67 to 67.79%, respectively. Powdery mildew, caused by Erysiphe polygoni DC, was the most prevalent disease with an incidence and severity mean of 59.09% and 30.92%, respectively. This could be attributed to susceptibility of the local cultivar, soil conditions and crop management practices. Soil physicochemical properties also varied among the wards and had a significant correlation with incidence and severity of diseases. These results could be useful in mapping green gram diseases and developing sustainable management options.Item BOTA 131: GENERAL MICROBIOLOGY(Chuka University, 2023-04-14) Chuka UniversityItem BOTA 338: LABORATORY TECHNIQUES IN BACTERIOLOGY(Chuka University, 2023-04-13) Chuka UniversityItem BIOC 220: BASIC METABOLISM I(Chuka University, 2023-04-13) Chuka UniversityItem ZOOL 103: VERTEBRATE ZOOLOGY(Chuka University, 2023-04-13) Chuka UniversityItem ZOOL 231: HISTOLOGY(Chuka University, 2023-04-13) Chuka UniversityItem ZOOL 233: VERTEBRATE ANOTOMY(Chuka University, 2023-04-13) Chuka UniversityItem ZOOL 240: GENERAL PARASITOLOGY(Chuka University, 2023-04-13) Chuka UniversityItem ZOOL 331: DEVELOPMENT BIOLOGY(Chuka University, 2023-04-13) Chuka UniversityItem ZOOL 438: MEDICAL BACTERIOLOGY(Chuka University, 2023-04-13) Chuka UniversityItem BOTA 0141: PLANT TAXONOMY(Chuka University, 2025-04-23) Chuka UniversityItem AGRI 223/BOTA 212: POPULATION GENETICS(Chuka University, 2025-04-14) Chuka UniversityItem BOTA 900: PHILOSOPHY OF BIOLOGY(Chuka University, 2025-04-14) Chuka University