Botany

Allelopathic potential of Tithonia diversifolia (Hemsl.) A.Gray and Lantana camara L. Leafy materials on growth, photosynthetic performance and yield of SB 19 and SB 97 soybean varieties

2025-01-01T00:00:00Z

Allelopathic potential of Tithonia diversifolia (Hemsl.) A.Gray and Lantana camara L. Leafy materials on growth, photosynthetic performance and yield of SB 19 and SB 97 soybean varieties KHAVERE, Emily Kavuludi Soybean is a legume which is widely grown in western Kenya for its edible seed but their yields are reduced by the effect of low soil fertility. The use of forest tree species and weeds as green manure has exacerbated soil fertility issues, potentially due to the allelopathic chemicals present in these organic materials. In Western Kenya, farmers are being encouraged to use shrubs as green manure such as Tithonia diversifolia and Lantana camara which have shown to improve soil fertility by 24% to 54%. Soybean varieties, SB97 and SB19 are known to be good yielders, whereas the two plants are being used as organic manure to increase nutrients in the soil for better crop growth and productivity, they are however also known to have allelopathic effects on some crops. Information available on their allelopathic potential on photosynthetic pigment, chlorophyll fluorescence and growth of soybean is not exhaustive. The main objective of this study was to investigate the allelopathic effects of fresh leaf aqueous extracts and fresh leaf material of T. diversifolia and L. camara on germination of seeds, growth, photosynthetic performance and yield of SB97 and SB19 soybean varieties. The specific objectives were to determine allelopathic effects of aqueous extract of L. camara and T. diversifolia on germination of SB97 and SB19 soybean varieties, to determine the allelopathic effects of fresh leaf segments of L. camara and T. diversifolia on growth and yield of SB97 and SB19 soybean varieties and to determine allelopathic effects of fresh leaf segments of L. camara and T. diversifolia on chlorophyll pigments and chlorophyll fluorescence of SB97 and SB19 soybean varieties. The experiments were carried out in the laboratory and greenhouse at Maseno University. In the lab, different concentrations of aqueous extracts, (25%, 50%, 75%, and 100%) and the control- tap water was used. Germination experiment was set in petri dishes and growth, yield and physiological parameters was carried out in the green house. Fresh leaf material of T. diversifolia and L. camara of 4g, 8g, 12g and 16g was added to soil in pots. The control only composed soil. This was replicated four times and laid out in Completely Randomized Design (CRD). Data on germination count were recorded daily, while growth and physiological parameters were recorded weekly. Data were subjected to analysis of variance (ANOVA) using SAS 9.1 to establish significant differences among treatments, varieties and plant materials. The treatment means were separated and compared using the Least Significance Differences (LSD) at P = 0.05. The results revealed that leaf extracts from Lantana camara and Tithonia diversifolia reduced the germination of both soybean varieties. These extracts contained bioactive compounds that inhibited germination, root and shoot growth and yield of Soybean varieties SB 19 and SB 97. Lantana camara exhibited stronger allelopathic activity than Tithonia diversifolia. On growth parameters, including shoot height, leaf number, leaf area, fresh and dry weights, and yield, the presence of allelochemicals in the biomass was suggested to have hindered growth by disrupting enzyme activities and nutrient uptake. Chlorophyll fluorescence and chlorophyll concentration analysis revealed that both leaf biomass materials impacted negatively on photosynthetic activity of the soy bean varieties. Allelochemicals in the fresh leaf segments of these plants decreased maximum photochemical efficiency and quantum efficiency, potentially reducing photosynthetic activity. Farmers are therefore advised not to incorporate Lantana camara and Tithonia diversifolia leafy biomass in farms where soy bean varieties SB 19 and SB 97 are growing. Master's Thesis

Effect of waterlogging on growth and development of selected green gram (Vigna radiata L.) varieties

2025-01-01T00:00:00Z

Effect of waterlogging on growth and development of selected green gram (Vigna radiata L.) varieties OCHAR, Samson Onyango In Kenya, green gram is mostly grown in arid and semi-arid areas under rainfed agricultural systems for both subsistence and commercial purposes. KAT 00301, KAT 00308, KAT 00309, KS20, N22 and N26 are grown in Kenya. However, the commonly grown varieties are KAT 00301 (dengu tosha), KAT 00308 (dengu biashara) and KAT 00309 (dengu karembo). Climate change has caused unpredictable rainfall patterns followed by floods which has led to waterlogging, which limits green gram production by affecting morpho-physiological and biochemical parameters hence food insecurity. There is need to fully understand morpho-physiological, biochemical and yield response of selected green gram varieties to waterlogging in order to identify waterlogging-tolerant varieties. The general objective of the study was to determine the effect of waterlogging on growth and development of selected green gram varieties. The specific objectives were to determine the effect of waterlogging on morphological, physiological, chlorophyll content and yield components of selected green gram varieties. The research was carried out under greenhouse set-up at the University Botanic Garden, Maseno. Ten-litre pots were arranged in a completely randomized design and filled with solarised soil obtained from the University Botanic Garden. Five seeds of KAT 00301, KAT 00308 and KAT 00309 were planted in the pots. Each pot was watered with 500 ml of water daily after and before the waterlogging treatment period. This continued throughout the study period. At 14 days after sowing (DAS), seedlings in each pot were thinned to three. Waterlogging treatments were induced at 21 DAS by dipping the 10-litre pots in larger 20-litre pots and maintaining standing water at 3 cm above the soil level for 3 days, 6 days and 9 days. The control treatment was watering each pot daily with 500 ml water throughout the study period. Each treatment had three replications. Collection of data began on 37 DAS and continued after every seven days throughout the study period. Morphological parameters data, i.e., the number of leaves were counted and fresh weight was determined using digital weighing balance. Data on physiological parameters; photosynthesis rate, stomatal conductance and transpiration rate were measured using LI-680 portable photosynthesis systems. Total chlorophyll content was determined using the Arnon method. Number of days to 50% flowering was counted and dry weight of 100 grains was determined using digital weighing balance. The data was subjected to analysis of variance using Statistical Analysis System (SAS) and separation of means done using LSD test at 5% level. Waterlogging significantly (P≤0.05) decreased the number of leaves, fresh weight, stomatal conductance, photosynthesis rate, transpiration rate, chlorophyll content and weight of 100 grains but significantly increased the days to 50 % flowering of the selected green gram varieties. The fresh weight, photosynthesis rate, chlorophyll content and weight of 100 grains were significantly lower in KAT 00308 as compared to KAT 00301 and KAT 00309. The number of days to 50% flowering in KAT 00308 was significantly more as compared to KAT 00301 and KAT 00309. KAT 00301 and KAT 00309 were less sensitive to waterlogging but KAT 00308 was more sensitive to waterlogging. KAT 00301 and KAT 00309 should be improved to waterlogging-tolerant varieties through breeding. Green gram farmers should plant either KAT 00301 or KAT 00309 to minimise losses due to waterlogging. Master's Thesis

Effect of maize- soya bean intercropping patterns on growth, yield and photosynthetic active radiation of soya beans in Kaimosi-Vihiga county, Kenya

2024-01-01T00:00:00Z

Effect of maize- soya bean intercropping patterns on growth, yield and photosynthetic active radiation of soya beans in Kaimosi-Vihiga county, Kenya AUMA, Millicent Othieno Cereal-legume combination is the common form of intercropping by most small-scale farmers in Sub-Saharan Africa (SSA). This is because of small pieces of land owned by farmers small causing overexploitation of resources like nutrients thus low productivity leading to food insecurity. In Kenya, food insecurity is rampant leading to importation of foodstuffs. The adoption of technologies like intercropping and use of agricultural inputs have been promoted to boost crop production. In Kaimosi, Vihiga County, majority of farmers despite the adoption of intercropping system have not appreciably improved the production particularly of soya bean that has remained at 0.2t ha-1 against potential of 2.5t ha-1. Therefore, there is need to further explore the best agro-technology like optimum intercropping pattern with a view to increased productivity and thus solving the global problem of food insecurity and poverty in the county. Maize-soya beans intercropping system helps improve soil fertility, protects the farmer against total crop failure, help in curbing the issue of food insecurity and increases farmers’ income. The objectives of this study was therefore to; determine the effect of maize- soya bean intercropping patterns on growth parameters of soya beans; determine the effect of maize-soya bean intercropping patterns on Photosynthetic Active Radiation and determine the effect of maize -soya bean intercropping patterns on yield parameters of soya beans. The study was conducted in Kaimosi Friends University research farm in Vihiga County. Complete randomized block design was used with six treatments which included; sole soya beans, sole maize, 1maize:1soyabean (1M: 1S), 1maize:2soyabean (1M: 2S), 2maize-2soyabean (2M: 2S) and 2maize:4soyabean (2M: 4S) each replicated four times. Each plot measured 3m x 3m and a space of 1m was left between them. Soya bean and maize varieties used were SB19 and H513 obtained from Kenya Seed Company, Kakamega. Three seeds were planted per hole and later thinned through uprooting to retain two seedlings per hole. 50% of each crop type were randomly tagged for data collection from each treatment and data collected after every 14 days from date of sowing. The study was carried out during the long and short rain seasons. Parameters such as soya bean height, number of leaves and leaf area index; Photosynthetic Active Radiation, pod length and pod number and yield were determined from the tagged soya beans plants in each treatment. Collected data was analyzed using GenStat statistical package version 15.2 to test for the significant differences between different intercropping patterns. Findings indicated that intercropping pattern had significant impact on growth and yield parameters. However, intercropping pattern significantly increased the growth of soya bean with highest height and leaf number found in 1M:1S pattern and the least in 2M;4S, while the highest LAI evidenced in 2M:4S and the least in 1M:2S pattern. Despite intercropping increasing the height of soya beans, it was not significant. The significant increase in growth in 1M: 2S pattern was because of positive phototropism and good PAR interception that led to optimum growth rate at 70 days after planting. The amount of PAR intercepted was significantly increased by the intercropping pattern (p<0.05) with the highest PAR recorded in 1M: 2S pattern followed by 2M: 4S and the least 1M: 1S at 70 DAP. The high PAR observed in 1M: 2S pattern was due to good spatial arrangement that provided a greater PAR conversion efficiency and maximum vegetative growth that enhanced high PAR interception. Intercropping pattern had a significant increase on pod number, pod length and final yield. This was due to optimum vegetative growth and high PAR interception during the vegetative and flowering stage, which reduced flower abortion and increased photosynthate production, for optimum number of pods, pod length and yield as seen in 1M: 2S pattern. The highest number of pods were recorded in 2M: 4S while the least recorded in 1M; 1S patter. The longest pods were recorded in 1M: 2S pattern followed by 2M: 2S while the least 2M: 4S with 3.84cm, 2.78cm and 2.26cm respectively. The highest yields were recorded in 1M; 2S pattern followed by 2M: 4S and least in 1M: 1S.There was significantly strong positive relationship between yields and the growth parameters, yield parameters and PAR (p 0.05). The positive correlation could be due to availability of growth material for the intercrop. Intercropping indicated yield advantage with an LER> 1. The findings from this study suggest the 1M: 2S intercropping pattern has potential for adoption since it recorded the highest soya bean height, number of leaves, pod length, intercepted the highest PAR, dry weight yields and efficiency in material utilization. The main recommendation derived from this study is therefore for agroecologists and small-scale farmers to practice the 1M: 2S arrangement of maize and soya bean since it exhibited effectual utilization of limited resources while at the same time giving maximum returns. Master's Thesis

Impact of altitude variation and grassland composiition on stemborer and fall armyworm population in maize farms and surrounding grasses in western Kenya during 2019-2020 rain season

2024-01-01T00:00:00Z

Impact of altitude variation and grassland composiition on stemborer and fall armyworm population in maize farms and surrounding grasses in western Kenya during 2019-2020 rain season NELIMA, Maryselah Grassland ecosystems adjacent to maize farms are often habitats for pests that pose significant risks to maize crops. Among these pests, lepidopteran stemborers and fall armyworm are the most detrimental, negatively impacting maize productivity. Although pests are known to thrive in grasslands, the influence of wild grassland composition on pest populations in maize fields and surrounding grasses across varying altitudes remains poorly understood especially in western Kenya. Given that altitude can significantly affect both plant and insect communities, studying this factor is crucial for developing effective pest management strategies. This study investigated the relationship between altitude and pest dynamics in maize farms and adjacent grasslands, focusing on four specific objectives, namely to: (i) assess the seasonal composition, distribution, and characteristics of grasses in grasslands near maize farms across four altitudes (low -1100 metres above sea level (masl); medium-1300 masl; high- 1500 masl; very high- 1700 masl) in western Kenya; (ii) examine the impact of altitude on grass species diversity and stemborer (Busseola fusca and Chilo partellus) and fall armyworm (Spodoptera frugiperda) populations across the four altitudinal zones; (iii) explore the influence of grass composition and characteristics on stemborer and fall armyworm populations in grasslands surrounding maize farms across the four altitudes; and (iv) investigate how surrounding grassland composition and characteristics affect stemborer and fall armyworm populations in maize farms across the four altitudes. The experimental design involved purposive sampling at four distinct sites of varying altitudes Mt. Elgon (very high elevation), Vihiga (high elevation), Homabay (medium elevation), and Lambwe (low elevation). Data were collected during the 2019 and 2020 short and long rain season respectively focusing on eight maize farms per site. Key parameters measured included grass diversity, percentage cover, species richness, and the abundance of stemborers and fall armyworms. Grass species were sampled using quadrats randomly placed in grasslands adjacent to maize farms, while inspecting 10 randomly selected maize plants from each farm assessed pest abundance. Environmental variables, including altitude, temperature, and soil moisture, were measured to contextualize grass and pest dynamics. Data analysis utilized the BiodiversityR package to rank grass species richness, Non-Metric Multidimensional Scaling (NMDS) for visualizing grass distribution, and Principal Component Analysis (PCA) to assess variable relationships. Spearman’s correlation explored the influence of grass characteristics on pest abundance, while Tukey’s HSD, linear regression, and Generalized Linear Models (GLM) evaluated altitude-pest dynamics relationships. Results showed a total of 55 grass species in 2020 versus 32 in 2019 across the four elevations. NMDS showed significant variation in grass composition by elevation (P < 0.005), with elevation affecting species composition more in 2020 (global R² = 0.454). Grass percentage cover was highest in Homabay in 2019, while Mt. Elgon showed increased cover in 2020. Lambwe displayed significantly higher grass fresh weight in both years. Additionally, fall armyworm abundance on maize farms correlated strongly with grass characteristics, especially grass cover, which negatively affected pest populations (Homabay rs = -0.93, P < 0.001). These results underscored the need for pest management strategies that account for interactions between grassland ecology, pest biology, and agricultural landscapes, emphasizing the importance of grass species composition, diversity, and abundance in shaping pest populations. Master's Thesis

Effect of Npk blended fertilizer application on soil physico-chemical properties, growth, physiology and yield of two finger millet (eleusine coracana l. gaertn.) varieties grown in acidic soils of Kakamega western Kenya.

2018-01-01T00:00:00Z

Effect of Npk blended fertilizer application on soil physico-chemical properties, growth, physiology and yield of two finger millet (eleusine coracana l. gaertn.) varieties grown in acidic soils of Kakamega western Kenya. SIMIYU, Wamalwa Dennis Finger millet is one of the most important cereal crops in Kenya. It is staple food rich in minerals and vitamins required for good health. Finger millet is a hardy crop compared to other cereals and it is for this reason that its currently being promoted in efforts to address food security. Western Kenya soils are acidic and soil acidity is a serious problem that affects crop productivity. County governments of Kakamega, Bungoma, Vihiga, Busia and Trans-Nzoia are promoting soil application of NPK blended fertilizer (10%N, 26%P, 10%K2O, 4%S, 8%CaO, 4%MgO and traces of B, Zn, Mo, Cu and Mn) to ameliorate the soil acidity. However, it is not known how the fertilizer affects soil, plant growth, physiology and crop yield. The study aimed to investigate the effect of NPK blended fertilizer application on the soil physio-chemical properties, growth, physiology and yield of finger millet in acidic soils of Kakamega. Experiments were conducted at the crop and livestock research field of Kenya Agricultural and Livestock Research Organization(KALRO) Kakamega station. Experiments were conducted during the short (October-January) and long (March-August) rainy seasons of 2015 and 2016 respectively. A Randomized Complete Block Design, involving application of 0,25,50,75 and 100 kg per acre of NPK blended fertilizer as the treatments. Two equal split application were done. Selected finger millet varieties of P-224 and Gulu-E which were sourced from KALRO-Kakamega. The varieties are commonly grown in Western Kenya and were known to be early maturing and drought resistant. Data was collected on soil pH, soil Aluminium, Calcium and Magnesium, finger length, finger width, plant height, days to 50% flowering, productive tillers, grain yield, chlorophyll content index and plant tissue nitrogen, phosphorus, potassium, magnesium, calcium were collected. Data collected was subjected to Analysis of Variance using GenStat statistical package version 15.1. Treatment means were separated at 5% probability level where significant differences (P≤0.05) were observed using the LSD test. Application of NPK blended fertilizer significantly reduced the amount of soil aluminium for both season with the highest reduction recorded under the 100 kg per acre fertilizer application. The soil pH, soil calcium and soil magnesium significantly (P≤0.05) increased linearly with increasing fertilizer rates. The application of NPK blended fertilizer significantly increased the plant height, finger length and finger width of both varieties. At the 75 kg/acre rate the leaves showed significantly highest total chlorophyll content in both varieties with the highest (29.17 umol) under variety P-224. The control showed the lowest physiological activities in terms of chlorophyll content, calcium, magnesium, nitrogen, phosphorus and potassium. Period to 50% flowering were significantly reduced due to application of NPK blended fertilizer where Gulu-E had 80 days at the highest rate while P-224 had 81 days on the same rate. At 50 kg/acre, the number of days to physiological maturity were significantly (P≤0.05) reduced under both varieties where Gulu-E took 107 days to mature. The number of productive tillers were significantly increased with increasing NPK blended fertilizer application rate especially under Gulu-E variety with a high number of 42 productive tillers per plot. The grain yield was significantly increased by application of NPK blended fertilizer with the peak observed at the 75 kg/acre rate for both varieties but Gulu-E outperformed P-224, therefore Gulu-E may be recommended to farmers due to its increased yield of 1.55 ton/ha. Farmers can improve finger millet yield and enhance their incomes while sustaining their soil fertility by using NPK blended fertilizer. The study concluded that application rate of 75 kg/acre of NPK fertilizer leads to the highest grain yield potential of finger millet varieties and positive liming effects that may ultimately reduce acidity of soils in the western Kenya region.

Melliferous taxa, floral calendar, Melissopalynology, and organoleptic characterization of aboriginal Ogiek honey in the eastern Mau forest block, Kenya

2019-01-01T00:00:00Z

Melliferous taxa, floral calendar, Melissopalynology, and organoleptic characterization of aboriginal Ogiek honey in the eastern Mau forest block, Kenya OMONDI, Philip Onyango Mau forest is one of the five water towers in Kenya serving as a critical catchment area for rivers and lakes in both Kenya and Tanzania. It plays a critical role in livelihood support. Eastern Mau forest has experienced most of the deforestation, loss of ecosystem vitality and biodiversity due to non-inclusion of local community in the conservation efforts. The Kenyan government legislative and policy frameworks have acknowledged the need for involvement of the Ogiek community. The community have long lived in the forest and area knowledgeable in forest conservation and bee keeping. Beekeeping by the Ogieks has been recommended under livelihood support programs to reduce destructive forest exploitation, this is by lack of information on: the authenticity of botanical and geographical origin of the Ogiek honeys, floral calendars to enhance apiary management and, organoleptic profile to enable sale in regulated honey markets. The objective of this study was to characterize melliferous flora, the botanical and geographical origin of Ogiek honeys and their organoleptic profile. A simple stratified random sampling research design was adopted with Kapkembu, Nessuit, and Mariashoni areas, Eastern Mau as the strata. The Ogiek bee keepers’ hives were the source of honey samples. Ten grams of each of the twenty-seven honey samples collected from Eastern Mau forest formed the unit of analysis. Approved methods of honey analysis were used. Collection of field data for development of floral calendar adopted belt transects around selected bee colonies for twelve months. Data was subjected to Analysis of Variance, Tukeys honestly significant difference post-hoc test, multivariate analysis, Jaccards similarity coefficient, quantitative descriptive analysis, and two-step cluster algorithms on SPSS base 20. Means of organoleptic data was subjected to Friedman’s test. Total of eighty-six plant species are foraged by Apis mellifera. Cissus rotundiflora Vahl. (Vitaceae), Trema orientalisL. (Ulmaceae), Maerua triphyllaA. Rich (Capparaceae), Aloe secundiflora Engl. (Asphodelaceae), Tribulis terrestisL. (Zygophyllaceae) and Polyscias fulvaJ.R. Forst. and G. Forst. (Araliaceae) are reported for the first time in Eastern Mau. Trees formed 41.86%, Herbs (25.58%), Shrubs (23.25%), and climbers (9.3%) of the bee forage. The peak availability of forage from the floral calendar was in April and May (2016) during the study. The Acacia species provide successive bloom mosaic year round. The highest similarity was observed in a comparison between (NE-S3-8) and NE-S1-8) within same site. The mean number of pollen types were highest in April (12.8), and lowest in December (9.7). There is a significant positive correlation (r=0.607*, 0.05) between number of pollen types and pollen density. Mean Shannon weaver diversity index was 2.32 across all seasons and sites of sample collection. Vernonia auriculifera, Cordia abyssinica, Acacia spp were very frequent pollen types, with Acacia type pollen having 85.2% frequency of occurrence in the honey samples. The rare, infrequent, frequent, very frequent pollen types observed in this study constitute the pollen spectrum that determine the geographical origin of Ogiek honeys in Eastern Mau forest. Botanical origin from predominant pollen types were Acacia spp type, Eucalyptus type, Croton spp. type, Albizia coriaria type, Cordia abyssinica type, and Vernonia auriculifera type. Floral fresh aroma family was the most dominant in 50% of the unifloral honey samples represented by Acacia, Croton and Albizia honey. Friedman’s test (N=12, df=7, X2 =14.07, Least Significant Difference= 23.52) revealed a significant difference in the sum of rankings in all organoleptic attributes. This study provides significant information on the floral calendar, unifloral and multifloral botanical origin as well as pollen spectrum denoting the geographical origin, and an organoleptic profile of unifloral Ogiek produced honeys Eastern Mau. The information from this study is important for extension services and policy development.

The effects of ocimum gratissimum, ipomoea batatas And brassica oleracea var botrytis extracts on the Growth and disease-causing capability of ralstonia Solanacearum in solanum tuberosum

2010-01-01T00:00:00Z

The effects of ocimum gratissimum, ipomoea batatas And brassica oleracea var botrytis extracts on the Growth and disease-causing capability of ralstonia Solanacearum in solanum tuberosum WAGURA, Alice Gathoni Irish potato (Solanum tuberosum L.) is a major cash and food crop worldwide. The production of this crop has in a great way been negatively affected by the extensive spread of bacterial wilt that is caused by Ralstonia solanacearum with over 50% crop yield losses reported in the last two decades. In addition, no bactericide has been developed to combat the disease and exercise of integrated control measures have not resulted to a sustainable solution. Scientists are putting a lot of efforts in research to get a solution that is effective, environmental friendly and that will enable the capacity of food production be improved to cater for the increasing human population. Plants have been shown to contain principles which are active against pathogens and among them are Brassica, Ipomoea and Ocimum species. It is on this basis that this research was aimed at determining the efficacy of locally available plants extracts in controlling the bacterial wilt disease in potatoes. The study was carried out in Maseno University Botany & Horticulture Department laboratory and the institution's Botanic Garden in 2007. The pathogen was isolated from infected potato tubers and cultured on nutrient agar medium. Ethyl acetate and methanol extracts of leaves of Ocimum gratissimum, Ipomoea batatas and Brassica oleracea var. botrytis and essential oils of. Ocimum gratissimum were evaluated for their efficacy at concentrations of 0.4, 0.2, 0.1, 0.05 and 0.025 mg/ml dissolved in dimethylsulphoxide in inhibiting in vitro growth of wilt bacteria. The experiment was extended to greenhouse where aqueous extracts of the three plants at concentrations of 2.5, 5 and 10% were evaluated for their efficacy in controlling the development of bacterial wilt symptoms on inoculated potato plants with control plants being inoculated with no treatment subjected to them. The extracts were also evaluated for their effect on different potato plants parameters. The experimental set up was randomized completely block design with 12 treatments and three replications. Data collectedwas subjected to Analysis of Variance (ANOVA) using SAS statistical package and the effects declared significant at 5% level. Linear correlation was used to compare the relationship between variables. The study has proved that the three plants contains principles that are active against wilt bacteria with essential oils from Ocimum gratissimum at O.4mglml exhibiting highest activity (10.lmm inhibition diameter) and Ipomoea batatas methanol extract at 0.025mglml exhibiting zero inhibition. The laboratory study has also shown a highly significant (P < 0.0001) interaction among plants, solvents and the various concentrations in the inhibitory activity. Aqueous extracts of the three plants have also exhibited varying levels of controlling wilt symptoms and promoting potato growth. The extracts of Ocimum at 10% and Brassica at 5% were the most effective in controlling the development Of wilt symptoms with average wilting index of 1.33 meaning less than 50% wilting occurrence. Potato plants treated with Brassica extracts at 10% exhibited an abnormal character of its leaf tips drying and thus .affecting their growth. In assessing the effect of potato wilting, the interaction between the plant and various concentrations was shown not to be significant (P> 0.05) in the first four days after inoculation. However it was significant (P

Evaluation of phenetic characters ·and growth Performance of native wood ear mushrooms (Auricularia species) on partially composted Agricultural wastes

2010-01-01T00:00:00Z

Evaluation of phenetic characters ·and growth Performance of native wood ear mushrooms (Auricularia species) on partially composted Agricultural wastes ONYANGO, Benson Odhiambo Wood ear mushrooms (Auricularia species) are a group of jelly fungi which occur as saprophytes on stumps or at the bases of dead or dying woody trees found in tropical regions. They have an ear shaped fruiting body from which they derive their common name. In other parts of the world, wood ear mushrooms have been domesticated and are valued for their nutritional and medicinal properties. Kenyan indigenous wood ear ~nushrooms which occur abundantly in Kakamega Forest have not been studied to evaluate their cultivation potential. Currently, the indigenous wood ear mushrooms face a threat of depletion due to over harvesting by the rural populace and rampant forest destruction. There is need to investigate their domestication potential in order to conserve their genetic resource. The objectives of this study were to evaluate the genetic diversity and to develop cultivation protocols for the indigenous wood ear mushrooms on malt extract agar, millet and sorghum grains and partially composted agricultural wastes. Mushroom germplasm collection was done at 3 different forest reserves within Kakamega Forest in Western Kenya. Mycelia growth was done through culturing of collected fruiting bodies on malt extract agar. External and internal mycelia and fruiting body features were evaluated and used to develop a descriptor for phenetic characterization of the wood ears. Data obtained from nine randomly selected accessions were used to calculate genetic similarity and to construct a dendogram. Some mycelia were used to raise spawns, which were used to inoculate the agricultural wastes. The agricultural wastes were treated to a short composting procedure, packed in heat resistant polypropylene bags and sterilized before inoculation. Inoculated substrates were kept in enclosed cabinets to allow mycelia propagation. They were then transferred to a cultivation room for mushroom growth. The cultivation experiment was set up as a two factorial Randomized Complete Block Design (RCBD) with variations in selected mushroom strains, different substrates and supplements. Three wood ear mushroom strains (Brown, Black, and White), four partially composted substrates (Wheat straws, Sugarcane bagasse, Grass straws and Corn cobs) and two supplements (Wheat bran and Rice bran) were used as treatments. Agronomic factors such as mycelia colonization rate, primordia initiation, yield and fruiting body quality were measured. Data collected were subjected to Analysis of Variance (ANOV A) to determine differences due to treatment effects. Mean separation was done using Least Significant Difference (LSD) at pSO.OS. Con-elation analysis was done to compare some of the variables. The results demonstrated significant genetic and agronomic variations between the strains. A significant dichotomy separating three (all white strains) out of the nine accessions at dissimilarity index of 0.318 was observed. The other two groups (black and brown strains) separated at a narrower dissimilarity index indicating that they were more closely related. From the cultivation experiment, no significant differences occurred between the strains on their mycelia growth on malt extract agar. The treatment 40% millet, 40% sorghum and 20% wheat bran gave the shortest duration of 10 days for spawn production. Averagely, the black strains gave the best performance on corn cobs supplemented with wheat bran giving values of3.7, 21, 318 g and 79% for fruiting body quality, number of fruiting bodies, fresh weight and biological efficiency respectively. The second best production was observed in wheat straw supplemented with wheat bran. Corn cobs and wheat straw supplemented with wheat bran were recommended to rural growers. Whereas morphological and productivity traits significantly separated the strains, further differentiation using molecular markers was recommended. Further investigation on their growth performance on other agricultural wastes and in different environmental conditions is necessary.

Effects of ungulate Herbivory and tree canopy on Ecosystem processes in Ruma National park, Kenya

2010-01-01T00:00:00Z

Effects of ungulate Herbivory and tree canopy on Ecosystem processes in Ruma National park, Kenya NYONGESAH, M.W. John Herbivores and tree canopies may have significant influences on savanna ecosystem functioning that are not yet clearly understood. Positive influences of grazers and trees may be associated with fecal deposition and the ability to fix atmospheric nitrogen respectively. On the other hand, grazers could negatively influence savanna functioning through trampling and vegetation removal, while negative influence of trees could be through shading, which reduces the amount of photosynthetic photon flux density ~ (PPFD) reaching_ the understory. Field studies were carried out in a humid tropical savanna in Kuma National Park, Kenya to understand how grazing by domestic animals and the Acacia trees influence ecosystem processes in the herbaceous layer community. The objectives of the study were; to monitor microclimate and soil moisture during an annual growth period, to measure the amount of biomass and nitrogen concentration in the soil and herbaceous layer vegetation during an annual growth period, to measure net ecosystem CO2 exchange (NEE) and ecosystem respiration (Reco) during the vegetative period and to determine how trees and grazing influence soil moisture, N distribution, biomass development and ecosystem CO2 exchange. Soil moisture was measured through gravimetiic method, plant and soil nutrients were monitored through elementary analysis, biomass was measured using harvest method while CO2 exchange was determined through gas chamber method. Measurements were stratified so that locations under the trees (understory) and in the open, outside the tree canopies were monitored separately to understand the interactive role of trees. Significant (psO.OOI) differences in peak aboveground+ biomass at the different locations was recorded with highest peak aboveground biomass of 902.7±115~ g m-2 Jecorded in non grazed _plots. Trees had significant Influence on soil moisture content as well as biomass production in both - grazed and non-grazed plots. Plants in the non grazed plots exhibited significantly (psO.OOI) higher N content compared to those in the grazed plots and similar trends were also .observed in the soil N content. Soil moisture, soil N, biomass production and ecosystem CO2 fluxes exhibited seasonality. Highest N concentration both in the plant material and in the soil occurred during the rainy period and higher N concentrations were observed in the tree understory compared to the open locations outside tree canopies. Significant seasonal changes were observed for NEE, Reco and GPP with Net ecosystem CO2 exchange increasing during the rainy season up to l Sumol m-2 S-I. Highest Reco values occurred during the rainy season, with values of 2004 ±O.5 and 23.5 ±O.5 umol m-2 S-1 in grazed and non grazed plots respectively. The study showed that grazing affects soil moisture and soil nutrient content and may significantly influence the savanna ecosystem functioning. This influence is however, modified by the Acacia trees through improved soil N content and reduced PPFD in the understory. The observed trends create a unique production mosaic (understory and open locations) of ecosystem function and productivity in the humid savanna. Humid tropical savanna ecosystem can therefore be a significant source and sink of both Nand C with processes that control their emissions being complex and influenced by a variety of interrelated factors such as quality and rates of organic matter input to the soil, soil chemical status, soil moisture status and soil temperature with herbivory acting as modifiers. These findings indicate that plant dynamics in humid tropical savannas are not a simple function of rainfall patterns or herbivory, but regulated by interactive effects of rainfall, grazing pressure and soil nutrients.

Anti-bacterial activity of Moringa spp seed.extracts and their water flocculation ability

2010-01-01T00:00:00Z

Anti-bacterial activity of Moringa spp seed.extracts and their water flocculation ability ATIENO, Walter . Otieno Water-borne diseases are some of the main problems in developing countries; about 1.6 million people compelled to use contaminated water. In many communities in the Winam Division,water clarification/purification methods are often inappropriate because of high cost and low availability of chemical coagulants, thus they consume water contaminated with disease causing microorganisms leading to outbreak diseases like typhoid. Natural products from Moringa spp. have been used as primary coagulants for water treatment. Objectives of the research were to establish the anti-bacterial activity of M oleifera and M stenopetala and their water clarification ability. 1 kg powder of shade dried and milled seeds of the M oleifera and M stenopetala were serially soaked in 2 litres of n-hexane and 2 litres of methanol to extract the active components and placed in a shaker for 4 hrs. Samples of water collected were processed for water coagulation studies. The nhexane and methanol filtrates of M oleifera Lam and M stenopetala seed extracts were then concentrated in a round-bottomed flask using a rotary evaporator under low temperature to obtain the extracts. 340ml n-hexane extract, 126ml methanol extract of M oleifera and 226ml n-hexane extract, 67ml methanol extract of M stenopetala were obtained. The anti-bacterial activity of nhexane and methanol extracts of M oleifera and M stenopetala against Salmonella typha, Vibrio cholera and Escherichia coli and water clarification ability of their methanol extracts were then evaluated using randomized complete block design. The results were analyzed using Analysis of Variance. The results indicated that, n-hexane extract had a higher inhibition on Salmonella typhii than Vibrio cholera and Escherichia coli and M oleifera was better water clarifier than M stenopetala. Aluminium sulphate achieved lower turbidity than M oleifera and M stenopetala extracts. The results showed that M oleifera and M stenopetala had antibacterial and water clarification ability. The outputs from this research would generate baseline data prerequisite for the future development of water purification and clarification products.