Browsing by Author "Okello, Victor Samuel"

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Allelopathic potential of mexican sunflower [tithonia diversifolia (hemsl) a. gray] on germination and growth of cowpea seedlings (vigna sinensis l.)
(2015) Musyimi, D.M.; Okelo, L.O.; Okello, Victor Samuel; Sikuku, P.S.
Invasive plant species when introduced into new environments may result into a number of ecological problems (Howard et al., 2000). They may influence other species through pathways such as allelopathy or phytotoxicity (Samuel et al., 2005; Imeokpara and Okusanya, 1994; Ayeni et al., 1997). Allelopathy is the inhibitory or stimulatory effect of a plant on another by chemicals released from the donor plant to the environment (Taiwo and Makinde, 2005; Bano et al., 2012). Allelopathy is a process by which plants release chemical compounds in their vicinity (Rice, 1984). Studies have shown that different plant parts release toxic metabolites into the soil that affect adversely germination and growth of plants (Kumar et al., 2008).
Assessing the Long-Term Changes in Selected Meteorological Parameters over the North-Rift, Kenya: A Regional Climatology Perspective
(Hydrology, 2024-12-03) Makokha, John Wanjala; Masayi, Nelly Nambande; Barasa, Peter; Ikoha, Peters Anselemo; Konje, Martha Muthoni; Mutonyi, Jonathan; Okello, Victor Samuel; Wechuli, Alice Nambiro; Majengo, Collins Otieno; Khamala, Geoffrey Wanjala
Understanding long-term trends in climatic variables is essential for assessing climate change impacts on regional ecosystems and human livelihoods. A regional analysis of climatic variables over some domains is inevitable due to their geographical location and importance to the agricultural sector. Due to the aforementioned demands, the current study analyzes, trends in precipitation (from Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS)), and minimum and maximum temperatures (from TerraClimate) over the North-Rift region of Kenya for over thirty (30) years using satellite data. The seasonal decomposition analysis was performed for each variable to explore the trends and residual components. The findings by the current study indicate that most counties, have experienced enhance precipitation which corresponds to a declining diurnal temperature from 2019 onwards. The seasonality component reveals repeated patterns or variations occurring at steady intervals within each region's data, hence suggesting a distinct regional seasonal trend in the selected meteorological parameters over time. Basically, all counties have reported a relatively constant variability in both maximum and minimum temperatures during the study period except from 2017 onwards where significant variability in the two properties is recorded. In conclusion, the foregoing results that the selected climatic variables exhibit significant spatiotemporal and interannual variability
Effective microorganisms and their influence on growth and yield of pigweed (amaranthus dubians)
(African Ethnomedicines Network (Nigeria), 2010-01) Muthaura, Chrispaul; Musyimi, David M.; Ogur, Joseph A.; Okello, Victor Samuel
Pigweed (Amaranthus dubians) plants grow widely in many parts of the world. It is a very popular indigenous wild vegetable and is usually utilized by many communities as a nutritional additive. Pigweed is becoming very popular nowadays because of its high nutritive value and simple growth habits. However there is very little information about growth of this plant, using effective microorganisms, thus this study is designed to evaluate the effect of inoculation of effective microorganism on growth and yield of pigweed. The experiment was performed in five liter pots representing various conditions in the field. It comprised of four treatments, replicated, five times and arranged in a complete randomized design. One set of the treatments consisted of soil collected from the field, while the other treatments consisted of soil and organic manure prepared using effective microorganisms, sterilized soil treated with effective microorganisms, and sterilized soil plus organic manure without application of effective microorganisms respectively. Shoot height, stem diameter, leaf number per plant, leaf area, leaf fresh weight, leaf dry weight, root fresh weight, root dry weight and chlorophyll a and b contents were determined. Inoculated pigweeds with effective microorganisms recorded highest values in all the parameters measured except the root dry matter accumulation. There were significant differences (p≤0.05) in shoot height growth, stem diameter, leaf numbers per plant, leaf area, leaf fresh and dry weight and root fresh and dry weights among treatments. There were no significant differences in leaf chlorophyll content among the treatments even though chlorophyll a and b contents were slightly higher in plants inoculated with effective microorganisms. The three other treatments had significantly lower values of the parameters determined. The results from this study demonstrated that growth and yield of pigweeds may be improved by inoculating the plants with effective microorganisms, and as a result reduce the use of fertilizers in production of this vegetable hence promoting sustainable agriculture. More studies would be needed to determine the effects of effective microorganisms’ inoculation on other amaranthus species.
Effects of fresh leaf materials of sesbania sesban (l.) merrill on the growth and photosynthetic pigments of nightshade (solanum nigrum l. var. popolo)
(INNSPUB, 2014-05-15) Mutisya, Musyimi D.; Okello, Victor Samuel; Anyango, Sikuku P.; Masila, Mutevu J.
Solanum nigrum L. is one of the African leafy vegetable consumed in Kenya. High cost of inorganic fertilizers has made it inaccessible by smallholder farmers leading to low yields. A study was conducted at Maseno University, Kenya to investigate the effects of Sesbania sesban fresh leaf materials on the growth of Solanum nigrum L. The study was conducted under greenhouse conditions using 3litre pots. Each pot was filled with 2kg of top soil and five treatments of fresh leaf materials of S. sesban incorporated at the rates of 0g (control), 15g, 30g, 45g and 60g. Ten seeds of S. nigrum L were planted in each pot and were watered daily until they germinated after which they were thinned to five seedlings per pot. The experiment was laid out in a completely randomized design (CRD) with 5 replications. Data on stem length, number of leaves per plant, leaf length, leaf breath were collected each week from the fifteen day after germination. Fresh and dry weights of the stems and roots, Leaf chlorophyll and carotenoids contents were determined at the end of the experiment. The data collected was subjected to ANOVA and means separated and compared using the least significant difference (LSD) at P = 0.05, using SAS statistical package. The study showed that there was a significant effect of application of fresh leaf material of S. sesban on the growth of S. nigrum plants, variety: popolo. Treatment consisting of 45g of fresh leaf material of S. sesban had the highest number of leaves, leaf area, plant height, fresh weight of the shoots and roots, and dry weights of shoots and roots. Chlorophyll a (chl a) and chlorophyll b (chl b) contents increased in all the treatments receiving fresh leaf materials of S. sesban. There were no significant differences in Chl a and chl b contents among the treatments receiving fresh leaf materials. Carotenoids contents of S. nigrum increased with increasing amounts of fresh leaf material of S. sesban. However, there was no significant difference in carotenoids contents between treatments. In conclusion fresh leaf material of sesbania promoted growth and increased photosynthetic pigments of S. nigrum, probably this was due to high amounts of nutrients supplied by S. sesban. The under exploited potential of S.sesban green manure can be harnessed in growing S. nigrum plants
Ethnobotanical study of medicinal plants used by Sabaots of mt. Elgon Kenya.
(African Ethnomedicines Network (Nigeria), 2010) Okello, Victor Samuel; RO Nyunja, R.O.; Netondo, Godfrey Wafula; Onyango, J Collins
Though the majority of people in Kenya and at Kopsiro Division in particular, rely on ethnomedicinal plant species to manage human ailments, the indigenous knowledge largely remains undocumented. Therefore, an ethnobotanical study was conducted on medicinal plant species used to manage human ailments at Kopsiro Division Mt. Elgon District Kenya. The objectives were to identify and document plants traditionally used for medicinal therapy by the Sabaots, to find out the method used for preparing and administering the drugs and to find out the conservation practices for the medicinal plants. Observations and semi-structured interviews were used to gather ethnobotanical data. 107 plants belonging to 56 families were identified and reported to be of medicinal value to the locals. Roots (47.3%) were the most frequently used parts of the plant followed by the bark (23.35%) then leaves (22.75%). The whole plant (1.8%), seed (1.2%), fruit (1.2%), sap (1.2%), flower (0.6%) and wood (0.6%) are least used in that order. The study revealed other hitherto undocumented medicinal plant species that may be new records for treating various ailments. Traditional medicine in Kopsiro division offers cheap, accessible and convenient remedy that suits the traditional lifestyle of the local community in comparison to the conventional medicine. Most medicinal plant species reported in this study were found to be under threat and this calls for urgent conservation measures so as to maximize the sustainable use of these vital resources in the study area.
Responses of slenderleaf rattlebox (crotalaria ochroleuca) to water deficit
(2017) Sikuku, P.A.; Musyimi, D.M.; Kariuki, S.; Okello, Victor Samuel
Water deficit affects plant growth and development thus affecting crop productivity. It is the major a biotic stress experienced in the vast semi arid and arid regions of Kenya and the world as a whole. Water deficit mainly causes reduction in plant growth and development. Crotalaria ochroleuca is an important indigenous leafy vegetable which is a legume grown and consumed in Kenya and Tanzania and other parts of Africa. The slender leaf rattlebox is very rich in protein, calcium, iron, Beta carotene and ascorbic acid and therefore can contribute to good human health therefore increased production of this vegetable should be used to solve the problem of malnutrition in the country and also act as food security. A study was conducted to evaluate the responses of slender leaf rattlebox to Water deficit.
The use of phytochemical composition of fifty (50) selected plants found in the university botanic garden, Maseno, Kenya to show
(2015-08-02) Omondi, Seline; Onyango, J.C.; Okello, Victor Samuel; Jeruto, Pascaline
Qualitative phytochemical analysis of 50 plants, five each from 10 selected families is presented. The ten plant families were selected based on their high plant frequency of occurrence within the botanic garden. The powdered crude samples of the leaves of the fifty plants were subjected to phytochemical analysis using standard experimental procedures. The ethanoic leaf extracts from the plants were tested for the presence of six phytochemicals. From the research, it is evident that saponins are the most abundant phytochemicals among the plants leaf extracts. They account for 32.43 %, followed by alkaloids (27.03 %) then flavanoids (14.86 %), steroids (12 .16%), terpenes (10.81%) and anthraquinones (2.70 %) respectively. PRM3 statistical programmes was used to analyse the phytochemical data, and ANOVA at P≤0.05 revealed that plant families Poaceae, Solanaceae and Rutaceae all have phytochemical composition mean of 60.0, indicating that the families are closely related. Apocynaceae, Asteraceae and Malvaceae families had phytochemical composition mean of 53.5, 50.3 and 50.2 respectively.The three means do not significantly differ, indicating the three families are related. Lamiaceae, Fabaceae and Acanthaceae had phytochemical composition mean of 46.8, 43.5 and 40.2 respectively. The means of these three plant families do not significantly differ, indicating that the three plant families are also related. The Araceae family had a mean of 30.7 which differs from all the other means, indicating that this family, based on its phytochemical composition, is not closely related to any of the nine plant families.