MST-School of Agriculture and Enterprise Development

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This collections contains bibliographic information and abstracts of Master theses and dissertation in the School of Agriculture And Enterprise Development held in Kenyatta University Library

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Survey and evaluation of nuclear polyhedrosis virus (NPV) for the control of helicoverpa armigera (hubner) (lepidoptera:nocduidae) on selected vegetable crops in kenya.
(Kenyatta University, 2000-09) Msanzu, Joseph Baya
Samples of Helicoverpa armigera larvae obtained from several sites and crops in Kenya in surveys carried out during June 1998 to October 1999 were examined at ICIPE, Nairobi. They revealed natural infection by nuclear polyhedrosis virus (NPV). Sixteen isolates were collected altogether. In laboratory bioassays on field collected third instar larvae fed on contaminated diet with two local NPV isolates and the Indian (ICRISAT) isolate, the cumulative percent larval mortality did not differ significantly but the local isolates were apparently superior. Percentage larval mortality recorded 9 days after inoculation for the Kenyan isolates were 78.3±7.38% and 68.3±5.68% respectively, compared to 55.9±2.10% for the Indian isolate. Larval mortality was found to be dose-dependent and increased with the larval instars. The Kenyan isolate 1 (Kibwezi isolate) had a higher slope of 0.685±O.1480 compared to 0.0981±O.14680 for the ICRISAT isolate while the LD50 values were 1.59976 x 1010OBs/ml and 3.178 x 1013OBs/ml respectively by probit analysis at 95% fiducial limits. In age-response studies with laboratory reared larvae, mortality was found to decrease with later instars. Cumulative percent mortality of second instar larvae reached 78.3±2.2% by the third day, 93.3±1.36% by day 6 and 100% by day 8. In pot culture tests, when aqueous suspension sprays of native HaNPV were applied on pigeon pea and snow pea potted plants artificially infested with third instar H armigera larvae, significant reduction in larval damage to pods and seeds were obtained. The grain yield per plant was also at par with yields of plants sprayed with two chemical pesticides, Larnbdacyhalothrin (Karate@) and Bifenthrin (Brigade@). Replicated small plots testing on vegetable pigeon pea also confirmed the potential of native HaNPV in providing satisfactory reduction in pest damage leading to grain yield benefits comparable to the chemical pesticide (Larnbdacyhalothrin) spray. Molasses (1%) increased viral activity both in the laboratory, pot-culture and field tests compared to 1% charcoal powder. Further efforts should be made to test the biological potential, characterize, improve and demonstrate the potential of native HaNPV for augmentation biocontrol of H armigera in Kenya.
Assessment of levels of natural radioactivity in surface soils around titanium mines in Kenya
(2011-11-07) Masore, Kefa Osoro
All human beings are exposed to radiation from naturally occurring radionuclides in soil and other environmental materials. Some of these exposures are not amenable to control and they are usually referred to as background radiation. Some work activities such as conventional mining inadvertently produce large quantities of naturally occurring radionuclides, which can result in additional and/or elevated levels of radiation exposure of people in the areas around the mining sites. Such exposures - induced or enhanced by human activities - are subject to control by regulatory authorities. In some instances there may be contributions from the two types of exposures and they must be separated before applying regulatory control. In this study, natural radioactivity levels in surface soils around the proposed titanium mines in Kwale district were determined from measurements of 78 samples of surface soils randomly sampled from two villages within the proposed mining area by using a hyper pure germanium (HpGe) gamma-ray spectrometer. The values of radioactivity concentrations in the soils and the likely radiation doses from contact with these soils were determined and are reported in this thesis. The radiological implication of these levels is discussed with regards to the impending mining operations in the area. The ranges and mean of radioactivity concentrations (Bgkg-l) obtained are. 8.4±0.4-43.6±1.5 (_27.6±1.7) for 232Th; 7.4±0.6-40.6±1.4 .(20.9±1.5) for 226Ra and 31.9±1.3-114.1±1.4 (69.5±3.2) for 40K, respectively. The likely absorbed dose rates in air above these soils were calculated from these radioactivity concentrations and found to be 8.5±0.5-36.9±1.1 nGyh-1 with a mean of 25.2±1.4 nGyh-1. The corresponding effective dose rates are 21.0±1.2-90.8±2.6 mSvy--1 with a mean of 62.0±3.5 uSvy--1, which are lower than the global average of 0.46 mSvy 1 and therefore of little radiological risk to the environment of the study subject.
A study of some socio-economic factors influencing roadside farming in Kikuyu and Limuru divisions Kiambu district
(2012-05-17) Mbwesa, Dorothy N.
This is a case study of roadside farming in Kikuyu and Limuru divisions, Kiambu district, Central Kenya. Roadside farming is an illegal activity involving the cultivation of food and fodder crops in addition to the grazing of animals on major road reserves belonging to the Government. The underlying objective of this study is to investigate some of the socio-economic factors motivating farmers to encroach on the road reserves and networks in order to establish roadside farm plots. Some basic concepts are reviewed and hypotheses and methods of data collection and problems encountered are elucidated. A background survey of the nature of the physical and human environments in which farmers base their decisions is provided, including the historical perspectives on land-population problems and transport and communication networks. The profile of roadside farmers and farm characteristics as well as the relationships between the attributes of roadside farming are presented. According to the Chi-square and regression analysis results, it is demonstrated that there are no significant relationships between: (a) Family size and roadside farm size; (b) Other legally-owned farms and roadside farm size; (c) Family income and roadside farm size; (d) Age of the roadside farmers and roadside farm size; (e) Distance between roadside farmers' residences and their farm plots; (f) Educational levels of the roadside farmers and the size of the plots owned. However, the factor analysis results yielded three factors including; financial gains attained from roadside farming, demographic factor and low family holdings which are used here to explain the existence of roadside farming in the study area. And, on the light of these findings, some policy implications and considerations are highlighted which could be implemented in an attempt to solve some of the roadside farmers problems. These are; land reform/redistribution, land resettlement, change of priorities in resource allocation towards rural areas, reduced population growths, provision of farm inputs and extension services and an improved physical planning of the local market centres in order to create better living conditions. In conclusion, it should be mentioned that roadside farming is a very controversial issue especially when considering the limited supply of the road reserves in relation to the ever increasing demand. Thus the livelihoods of the farmers can only be improved if the socio-economic problems are addressed to by policy makers and development planners.
Organization and development of Kikuyu agriculture, 1880-1920
(2012-05-17) Muchoki, F.M.
The study focuses on the organization and development of Kikuyu agriculture in Kiambu District between the years 1880-1920. It investigates the internal dynamics and innovative changes that characterized Kikuyu agriculture in these years. It examines the indigenous principles through which the Kikuyu farmers interpreted, predicted and intervened in the natural environment. It also examines the local social organization and the external political and economic factors, which affected the Kikuyu agricultural system in these years. It is argued that Kikuyu agriculture whose organization was complex underwent major structural changes and was capable of initiating and accepting novel practices. In this study, we do not enquire about traditional systems to glorify them as halcyon days, but rather we are seeking to establish Kikuyu possession of knowledge about environment and ecology and the adaptation that the Kikuyu have made to them. We are interested in understanding how the Kikuyu agricultural system functioned in order to understand how it has been transformed. Recent theoretical formulation of colonial agriculture especially the dependency accounts, while correct in essential respects, are seen to have certain shortcomings. As Zeleza (1983, 162) has pointed out, "Writers are so overwhelmed by the structural forces of colonial state pressures against the peasants, that in the final analysis, they lose sight of the peasants, that is, how they have struggled against, adapted to and conditioned the penetration and subsequent development of capitalism in peripheral areas". Despite the dominance of settler farming, Kikuyu commodity production and agricultural output increased rapidly. However, while the establishment of colonial rule was to provide new opportunities for some Kikuyu to expand their trade and agricultural output, "it was also to hinder and in some cases to ruin certain traditional patterns of agriculture" (Zeleza 1983, 162). Colonialism not only drastically altered the social and political organization of the Kikuyu but it also altered the ecological organization. This study will examine the nature of this reorganization.
Demand for tractor services in Trans-Nzoia district
(2012-05-17) Obilo, Jeremiah Abok
The current study was formulated to investigate into the factors that affect the demand for tractor services among smallholders in Trans-Nzoia district. Questionnaire was used to collect data and about 113 small farm holders were interviewed. Multiple regression analysis was then used to determine the association between the use of tractors and the various postulated independent variables. The empirical findings of the study indicate that there is a strong correlation between use of tractors and the following: land acreage, the tractor hire charges; though contrary to a priority expectations, empirical evidence of this study show apparently a weak relationship between income variations and the demand for tractor services. The researcher suggests that this might be a reflection of low-income levels of small farm holders. Other variables like age of the farmer; education levels, and their main occupation were statistically insignificant at the 5 per cent level. The study also revealed several tractor services, which small farm holders utilize. Among these, ploughing activity was the most used tractor service; and 92.5 per cent of the respondents had used tractors for ploughing during the period of data collection. Other tractor services, which were identified, were re-ploughing, harvesting, planting shelling and transport. Finally, based on the statistical results various policy implications were suggested.
Effects of soil on pathogenicity of meliodogyne incognita on okra
(2012-06-13) Mbugua, Joyce Waceke
Tests were conducted both in the field and greenhouse to investigate effects of i. chicken and goat manure, sawdust (Cyprerssus governiana L.), kale leaves, bean stems, maize stalks and Nitrogen-Phosphorus-Potassium (20:10:10), (ii) time of incorporation of the organic materials into the soil and (iii) solar heating of soil using 0.07, 0.13 and 0.26 cm-thick polyethylene mulches on pathogenicity of Meloidogyne incorgnita (Kofoid and White) Chitwood on okra (Hibiscus esculentus L cv. pusa sawani). The organic materials and N-P-K (20:10:10) were incorporated into the soil 14 days before planting and at planting time, respectively, at the rate of 20 gms and 4 gms, respectively, per 15 cm diameter plastic pot containing unsterilized soil or per planting hole in tests designed to investigate effects of the materials on pathogenicity of M. incognita. An equal amount of organic material was incorporated into the soil 14, 28 and 42 days prior to inoculation in tests designed to investigate effects of time of incorporation of the organic materials on pathogenicity of M. incognita. Twenty one day old okra seedlings germinated in sterile sand and an inoculum level of 2500 + 50 M. incognita eggs and second stage juveniles (J-2) were used in all tests. A completely randomized block design with four and five replications per treatment was used in tests designed to investigate effects of solar heating of soils and organic materials, respectively, on pathogenicity of M. incognita. A split plot design with three replications per treatment was used in tests designed to investigate effects of time of incorporation of organic materials on pathogenicity of M. incognita. Plant heights and stem diameters were taken 21 days after inoculation and biweekly thereafter for 90 days. In addition, fresh fruit and dry shoot weights and number of fruits per plant were taken at harvesting time, 90 days after inoculation. A 0-4 gall rating scale, where 0 = no galls; 1 = 1-25%; 2 = 26-50%; 3 = 51 - 75% and 4 = 76 - 100% of root system galled was used to assess disease severity. Meloidogyne incognita counts were made 90 days after inoculation. Goat and chicken manure, kale leaves, sawdust and N-P-K suppressed pathogenic effects of M. incognita by up to 79.21%, 75.69%, 67.24%, 22.09% and 90.25%, respectively, as was revealed by the respective coefficients of determination (r2) values of 0.7921, 0.7569, 0.6724, 0.2209 and 0.9025. The effects of maize stalks on pathogenicity of M. incognita varied from one test to another. The suppressive effects of goat manure, chicken manure, kale leaves and sawdust decreased by 24.31%, 20.13%, 20.57% and 98%, respectively, when the materials were incorporated into the soil 42 days prior to inoculation. The suppressive effects of maize stalks, however, increased by 1.97% when the material was incorporated into the soil 42 days prior to inoculation. Although bean stems incorporated into the soil 14 days prior to inoculation did not suppressed by up to 77.44% (r2 = 0.7744) and 76% (r2 = 0.76) when incorporated 28 and 42 days prior to inoculation, respectively. Solar heating of soils using 0.07cm and 0.13cm-thick transparent polyethylene mulches suppressed pathogenic effects of M. incognita by up to 100% (r2 = 1.00) and 59.29% (r2 = 0.5929), respectively. Besides poor plant growth, plants grown in soils mulched with the 0.26cm - thick polyethylene mulch supported low gall indices and numbers of M. incognita.
The influence of nutrients and phenolic componds of cabbage collard green, lettuce and spinach on the biology of cabbage aphid brivicorgbne brassicae(h) and peach potato aphic myzus persicae (SULZ)
(2012-06-13) Mbugi, Jenard Patrick
Defence of plants against pests may depend on texture and composition of the plant surface, absence of nutrients required by the pest and production of toxins or deterrents (Levin, 1971). Majority of toxins or deterrents already identified comprise of plants secondary constituents. One of the most important groups of plants secondary constituents playing a defensive role against insect pests are phenolic compounds. Using Folin-Denis assay, cabbage, collard green, lettuce and spinach were shown to contain a significantly different mean concentration of total phenols, followed by collard green, lettuce and spinach were shown to contain a significantly different mean concentration of total phenols, followed by collard green, cabbage while spinach had the lowest concentration. Experiments on the identification of phenolic compounds using Thin Layer Chromatography (TLC) method revealed that cabbage, collard green, spinach and lettuce contained seven, ten, eight and nine phenolic compounds respectively. Laboratory experiments showed that lettuce and spinach could not successfully support a culture of Brevicoryne brassicae (L.) and all the nymps that were fed on the leaves of the two test cultivars died ten hours after introduction. Further treatment of the spinach and lettuce leaves with cabbage extract had no effect and the two test cultuvars even after treatment with cabbage extract still could not successfully support a culture of B. brassicae. Results on the treatment of cabbage leaves with spinach and lettuce extracts revealed that the extracts had no effect on the survival of B. brassicae. The mean numbers of B brassicae nymps found surviving seven days after introduction to feed on cabbage leaves treated with spinach and lettuce extracts were not significantly different from the mean numbers of the nymphs introduced to feed on untreated cabbage leaves. B. brassicae fed and reproduced successfully on cabbage and collard leaves. The results of this experiment showed that the mean maturity, fecundity and post-reproductive period of B. brassicae on cabbage and collard green were not significantly different. However, the mean longevity and reproductive period of B. brassicae on collard green were significantly longer than on cabbage. Experiments on Myzus persicae (Sulz) reared on cabbage, collard green leaves showed that the mean maturity and longevity of aphid on the three test cultivars were not significantly different. However, the mean fecundity, reproductive periods and post-reproductive periods were significantly different. The highest mean fecundity was recorded on lettuce followed by collard green while cabbage had the lowest. The longest mean reproductive periods and post -reproductive periods were significantly different. The highest mean fecundity was recorded on lettuce followed by collard green while cabbage had the lowest. The longest mean reproductive period was recorded on collard green while cabbage had the shortest. The differences between the mean reproductive period on lettuce and cabbage were not significant and so were those between collard green and lettuce. The mean post reproductive period was longest on lettuce followed by cabbage while the shortest was on collard green. The mean concentration of nitrogen, phosphorous, sulphur, calcium and magnesium in all the four cultivars were not significantly different. However, the mean concentration of potassium, copper, manganese, iron and zinc showed some significant differences. The mean concentration of potassium was highest in lettuce and lowest in cabbage. The differences between the mean concentration of potassium in cabbage, collard green and spinach were not significant and so were those between spinach and lettuce. The mean concentration of copper was highest in spinach and lowest in cabbage. The differences between the mean concentration of copper in cabbage, collard green and lettuce were not significant and as were those between spinach and lettuce. The mean concentration of manganese was highest in spinach followed by lettuce, cabbage while collard green had the lowest. The mean concentration of iron was highest in lettuce followed by spinach and cabbage while collard green had the lowest. The mean concentration of zinc was highest in spinach and lowest in lettuce. The differences between the mean concentration of zinc in cabbage, collard green and lettuce were not significant.
Pesticide use and misuse by small scale farmers in Kiambu, Kenya
(2012-06-13) Karembu, Margaret Gathoni
This study was set to investigate the use of pesticides by small-scale farmers and its implications on the environment. It further sought to find out whether illiteracy causes misuse of pesticides and if provision of information on pesticides reduces their misuse and mishandling. Three divisions in Kiambu district were selected using the cluster sample technique for interviews. The interview schedules contained questions aimed at answering the specific research questions. Data was analysed using descriptive statistics i.e. frequencies, averages and percentages. In some cases, the responses were reported verbatim. The validity of this study relied on the assumption that the interviews were reasonably honest and expressed their true feelings when responding to the interviewer's questions. It was established that some small-scale farmers used a wide range of extremely hazardous pesticides, which were either banned or severely restricted for use in developed countries. These included Dichlorodiphenyltrichloroethane (DDT), dieldrin, heptachlor, cypermethrin and lindane. Factors such as the economic status of the farmers and the prevailing climatic conditions were found to contribute to pesticide misuse and mishandling than illiteracy. In view of the problems of pesticide use, it was recommended that measures be taken to enforce pesticide regulations and legislation. The introduction of laws and regulations concerning disposal of unused pesticides and their containers should be supported while improved methods of packaging would reduce hazards arising from pesticide use. Further, labelling and advertising of pesticides should be monitored. Environmental education should incorporate pesticide safety education in the whole education system to sensitise and increase public awareness on the risks and potential problems of pesticide use and handling.
Molecular characterization sequence variation in the rDNA region of root-knot nematode (Meloidogyne sp.,) in indigenous lefy vegetables
(2012-12-03) Mwangi, John Muturi; Gichuki, Charity; Waceke, J.W.
Indigenous leafy vegetables (IL V s) are plants whose leaves or aerial parts have been integrated in a community's culture for use as food over a large span of time. In the past, traditional societies have exploited edible wild plant resources to obtain their nutritional requirements. Solanum nigrum, Amaranthus hybridus, and Cleome gynandra are the most used ILVs. Root- Knot Nematodes (RKN) belonging to the genus Meloidogyne are the most economically important nematode pests affecting IL V production and have a diverse host range. Plant-parasitic nematodes are responsible for global agricultural losses' amounting to an estimated $157 billion annually. Most IL V crops produced are susceptible to nematode injury, particularly by root knot nematode and sting nematodes. Plant symptoms and yield reductions are often directly related to pre plant infestation levels in soil and to other environmental stresses imposed upon the plant during crop growth. As infestation levels increase so then do the amount of damage and yield loss. Most previous studies on the diversity of Meloidogyne spp. have focused on morphology (for example: perineal patterns, stylet structure, body length), and the response of the populations to differential host test. Morphological differences may be absent or difficult to observe. Identification by these procedures is difficult even for qualified taxonomists. Isoenzyme electrophoresis has also been used to characterize RKN populations. The esterase phenotypes are species-specific and are a good tool for identifying RKN. PCR-based diagnostics offer possibilities for precision, sensitivity and quantification. Ribosomal DNA distinguishes many species of nematodes, investigates intraspecific variation and examines evolutionary relationships. In this study esterase phenotypes (EST), Malate dehydrogenase (MDH) was used. Four esterase phenotypes were recognized on the basis of single bands or combinations of several bands. One Mdh phenotypes (i.e. Nl) and four EST phenotypes (i.e. 12, 13, Al and A2) were detected. Three species were identified from the populations, of which 20 were M incognita (Mdh-Est phenotype NI-I2), 10 were Mjavanica (NI-B), 10 were M arenaria (Nl- A2). All the three species amplified using SSUrRNA produced a single PCR product of 700 bp. The PCR products were then purified and subjected to sequencing. Sequences were aligned with sequence alignment tools (ClustaIW2) to show areas of variability and areas of conserved regions. The obtained sequences were compared with nucleotide sequences in the Gene bank using the BLAST Software to determine similarities. From the blast analysis several sequences of Meloidogyne nematodes (5 S ribosomal RNA) were identified with regions that matched with the obtained sequences. The nearly complete 5S rDNA sequences obtained from the 11 sequences varied from 675 to 692 base pairs. The sequenced products were aligned to investigate sequence diversity and infer phylogenetic relationship among the species. Phylogenetic analysis was done by MEGA (Molecular Evolutionary Genetic Analysis) computer program. The dendrogram of the phylogenetic tree was drawn using a web based program which confirmed the sequences of the most four common Meloidogyne species. The results of the study will be used to design best IPM programs and better understand taxonomy.
Effectiveness of macro propagation technique in production of healthy banana seedlings in Eastern and Central regions, Kenya
(2013-03-20) Njau, Njeri
Banana (Musa spp.) is one of the most important food and cash crops in Kenya. It provides food security. nutrition and income for many smallholder farmers. Bananas are eaten ripe or cooked depending on the variety. Despite its economic importance banana production faces major challenges including scarcity of high quality seedlings insect pests and diseases. Demand for pest free and high quality planting materials has been on the increase. Naturally regenerated suckers that are preferred by farmers are more likely to carry pests and diseases leading to reduced productivity and a short lifetime of new plantations. Tissue Culture has been introduced but its adoption has been low due to the high costs and skills involved. To address this constraint macropropagation has been introduced as an alternative propagation technology. The technology can be implemented with little capital and skill. The study was aimed at assessing whether macropropagation technology can produce healthy banana seedlings. A survey was conducted to identify the current important diseases and insect pests of bananas in Eastern and Central Kenya. Macropropagation nurseries were established at Kenyatta University and in farmers' fields at Mathioya, Kirinyaga, Embu East. Meru Central and Mitunguu and Ntharene in Imenti South District. These sites represent different agroecological zones. including high. mid and low altitudes. Corms obtained in accordance with established quality assurance protocols were propagated and the health of the macropropagated banana seedlings monitored. Macropropagation was done in two cycles. the first in Feb - June 2011. and the second from July - November 2011. The importance of the isolated organisms in banana health was determined through pathogenicity tests carried out under controlled conditions. To determine the effectiveness of macropropagation protocol in eliminating pathogens. corms were artificially inoculated with Radopholus similis, Fusarium oxysporum f. sp. eubense (Foe) andXanthomonas vasieola pv. musaeearum (Xvm) followed by monitoring health of the seedlings from the inoculated corms. Fusarium wilt and Sigatoka were recorded as the most important diseases with 66 and 50% incidence respectively. while nematodes and banana weevil were the most important pests with 21 and 17% incidence. respectively. An average of 98 and 100% healthy seedlings resulted from the first and second cycles of macropropagation. Under simulated infection. macropropagation did not eliminate Foe and Xvm but completely removed plant parasitic nematodes (PPN). The study found that macropropagation technique is an effective method to produce healthy banana seedlings however precaution is needed to ensure quality of the seedlings where Xvm and Foe are present. The key control points for safeguarding health and quality of the macropropagated seedlings is during certification of corm sources to ensure selection of healthy corms the process should be done aseptically and the corms should be treated before planting.
Low Cost Issue Culture of Selected Cassava(Manihot esculenta Crantz)and Sweet Potato(Ipomoea batatas(l)Lam) Varieties
(2013-03-21) Ogero, Kwame Okinyi; Mwangi, M.; Mburungu, G. M.; Ombori, O.
Drought has become a major contributor to food insecurity in sub-Sahara Africa. Drought-tolerant crops such as cassava and sweet potato can help alleviate this situation. However, lack of affordable healthy planting materials of farmer-preferred varieties is a major constraint to sweet potato and cassava production. Conventional tissue culture technology offers an important solution to this but it is very costly, making plantlets out of reach for resource poor farmers. Hence, it is necessary to have low cost options for micropropagation of planting materials. One way of doing this is to substitute the conventional source ofMurashige and Skoog (MS) media salts with alternative sources that are available 10call¥~:'This study sought to compare the cost of regenerating selected cassava and sweet potato "varieties using alternative nutrient sources and the conventional MS nutrient sources. Another objective was to find out if there is any genotypedependent response to regeneration using different media. Two varieties of each crop (KEMB 36 and Tainung for sweet potato and Muchericheri and KME 1 for cassava) were subjected to three treatments with different media composition and replicated nine times. In the first medium (LCM 1), Easygro'" vegetative fertilizer (27:10:16 (N: P: K) + microelements) from Osho Chemical Industries Limited was used as an alternative source for MS basal salts. In the second media (LCM 2), the conventional sources of four MS macronutrients were substituted individually with locally available fertilizers while Stanes Iodized Microfood® was used as the low cost source of micronutrients. Table sugar was used as an alternative source of carbon while the modified conventional MS medium (CM) was used as the control. Growth parameters including numbers of nodes, roots, leaves and plant heigh.t.we.re recorded at 7 and 14 days intervals for cassava and sweet potato, respectively. This was.carried out over a period of five weeks for cassava , and six weeks for sweet potato. The use of LCM 1 for cassava micropropagation led to a reduction of 96.3% in the cost of the ~utrient medium while LCM 2 led to savings of up to 95.5%. For sweet potato a cost reduction of 96.9% was realized with LCM 1 while LCM 2 led to cost reduction of 94.4%. LCM 1 produced better results compared to LCM 2 for cassava regeneration for all the four parameters assessed. The two cassava varieties had regeneration indices of 3-7 nodes per plantlet during initiation and 3.7-6.9 nodes per plantlet during multiplication on all the media. Leaf formation for the two cassava varieties after the sixth week of culture ranged between 2.7 and 7.3 leaves per plantlet on all the media during initiation and 4-7 leaves during multiplication. Muchericheri produced significantly (p:S0.05) higher number of roots on LCM 1. The two cassava varieties had no significant (p2:0.05) differences in root production on LCM 2. Sweet potato varieties produced better results on LCM 2 compared to LCM 1. KEMB 36 had a regeneration index of 7.8 nodes per plantlet on LCM 2 during initiation while Tainung had a mean of 3.8 nodes per plantlet after the sixth week of culture. The two sweet potato varieties recorded regeneration indices of 3.3-7.1 nodes per plantlet during multiplication. The variety KEMB 36 had better leaf production on LCM 2 compared to Tainung and vice versa on LCM 1 during initiation. Acclimatization of cassava was best on vermiculite while for sweet potato it was on a mixture of rice husks and red soil in the ratio 1:2. This study has shown that it is possible to reduce the cost of cassava and sweet potato tissue culture by adopting alternative nutrient sources. However, the differential responses among varieties calls for further investigation.
Characterization of Soil Mineralogy in Relation to Soil Fertility Functional Properties for Selected Countries in Africa
(2013-08-13) Kamau, Mercy Nyambura
Africa’s development depends heavily on soil ecosystem services. However current soil degradation coupled with increasing pressure on land is threatening the soil resource base. There is an urgent need to establish soil health surveillance systems to guide investments and monitor trends in soil health status and impacts of interventions. Surveillance systems require appropriate and rapid, low cost methods that directly measure soil functional properties and can be applied at larger scale. Spectroscopic methods that directly measure organic and mineral composition hold promise for fulfilling this role. Infrared molecular spectroscopy (IR) is one method that has shown promise for predicting many soil functional properties. Xray diffraction spectroscopy (XRD) is another promising method, which directly determines soil mineral composition, but has been little researched as a tool for quantitative prediction of soil functional properties. However a comprehensive knowledge of soil mineralogy in Africa is lacking due to poorly and fragmentally coordinated scientific investigations coupled with the limitations in the traditional analytical techniques. The aim of this study was to develop a rapid XRD measurement protocol and evaluate the ability of X-ray diffraction technique to rapidly predict soil functional properties based on mineral composition. Geo-referenced samples associated with the Africa Soil Information Service (AfSIS), taken from a set of 10 sentinel sites randomized over sub-Saharan Africa, were used for characterization. A total of 160 topsoil samples taken from 16 randomized points of ten 100-km2 sites: Tanzania (3 sites), Malawi (2 sites), Mali (1 site), Burkina Faso (1 site), Kenya (2 sites) and Ghana (1 site) were characterized for chemical properties, particle size distribution, engineering properties and bulk mineralogy. Variation of the mineralogy within and between sites was explored using principal component analysis using the R statistical software, as a precursor to exploring relationships with directly measured soil properties and soil fertility diagnostics. The clustering of individual minerals and the distributions of the soil fertility variables identified across the sites appeared to relate to differences in mineralogical functional groups, supporting the hypothesis that mineralogical data could be used to predict functional properties. The findings therefore suggest opportunity for improving soil assessment using information on soil mineralogy. For instance XRD information on mineralogy can be combined with information from soil physico-chemical properties, to provide powerful diagnostic capabilities, for low cost and rapid prediction of soil functional properties. Further work should aim to develop direct quantitative predictive relationships between soil functional properties and mineralogical composition using the full set of AfSIS reference samples.
Etiology, Epidemiology and Management of Dieback Disease of Passion Fruit (Passiflora spp ) in Central and Eastern Regions, Kenya
(2013-10-15) Wangari, Wangungu Carolyne; Mwangi, M.; Kahuthia-Gathu, R.; Muasya, R.
Passion fruit is important in Kenya for nutrition and income. Current production is low and this is largely due to pests and diseases. In Kenya, major passion diseases include Fusarium wilt, Phytophthora canker, Brown spot, Woodiness virus and Dieback. Dieback causes over 80% of tota! produce loss and has negatively affected the passion fruit value chain. The objective of this study was to identify dieback pathogens, determine their aggressiveness, investigate its epidemiology and identify effective management measures. A survey was. carried out in major passion fruit growing areas in Central and Eastern Kenya. Three research sites were set up in the study areas and 1 at Kenyatta University, where epidemiological and disease management trials were done. Passion fruit varieties assessed were Passiflora edulis var Sims and KPF 12 hybrid. Diseased samples were collected for isolation and identification of pathogens in the laboratory. Pathogenicity tests determined aggression of the isolates. Data on disease severity were collected using a dieback scoring chart (with a scale of 1 to 5, subjected to analysis of variance and means separated by LSD at P = 0.05 using the Tukey's test. Results showed that dieback is a disease complex caused by multiple pathogens (Genus Fusarium, Phytophthora, Alternaria and Ascochyta). Disease was most severe when pathogens were inoculated in combinations of 3 and 4. Proper field maintenance practices reduced disease incidence and severity (12% and 1.6 respectively) in Meru B while poor maintenance yielded high levels (55% and 4.0 respectively) in Mathioya. Agronomic practices important in transmission of dieback pathogens on the purple variety were pruning, grafting and wounding (P :::;0.05). Mavuno and TSP fertilizers boosted plant growth leading to lower disease scores of 2.2 and 2.3, respectively, as compared to the control (2.92). None of the fungicides evaluated was curative. Plants treated with Ridomil MZ had a low severity score (2.1), while those treated with Milraz had a higher score (2.7). Water stress increased severity thereby suggesting that the lower the amount of water/rainfall available to a plant, the higher the dieback severity and vice versa. The relationship between rainfall arid severity yielded a negative correlation coefficient (r = -f). 70). Multiple pathogens imply that there should be integrated measures for effective disease control. Positive effect of fertilizers indicates that proper nutrition is crucial to alleviating effects of dieback. This study identified dieback pathogens, showed that proper field maintenance and nutrition are important in disease management and indicated that major fungicides currently in use in production are ineffective. Recommendations were that· although attention is largely on dieback, management of other passion diseases should not be neglected. There is need to strengthen role of nursery operators and training farmers/nursery operators on importance of tool disinfection. Dieback management packages should target multiple pathogens. To boost production there is need for nationwide rotational programs. This information is crucial in dieback disease management programs and will contribute towards reviving the passion fruit industry in Kenya. 1
Effects of Lime, inorganic P and inoculation on Soil Chemical properties and Grain Yields of Maize and Soybean in Western Kenya
(2013-10-17) Onyango, Maurine Akinyi; Danga, B. O.; Odendo, Martins
Low crop responses to fertilizer application among small holder farms are common phenomena in degraded acidic soils of western Kenya. Continuous growing of maize without commensurate soil nutrient replenishment coupled with application of soil acidifying fertilizers, especially Di-ammonium Phosphate (DAP) and Sulphate of ammonia (SA) have aggravated the soil acidity problem. An on-farm trial was sited in Shianda sub-location, East Wanga division in Mumias district, Western province, Kenya during the 2011 long rain (LR) and short rain (SR) seasons to determine the effect of lime, inorganic P, inoculation on soil chemical properties and yields of soybean (Glycine max L.) and maize (Zea mays L.). The treatments included, 2 lime rates (0, 2.5 t/ha), 2 inorganic Prates (0, 30 kg P/ha) with or without inoculation (Rhizobium japonicum) of soybean. The eight treatments were arranged as factorial in RCBD with four replicates. All data were analyzed with the ANOV A procedure of the GENST AT statistical software and treatment means separated using least significance difference at (P < 0.05). Regression analysis was performed to examine relationships between plant and soil parameters. Benefit-cost analysis was performed on maize and soybean grain yields to determine the treatments with the most profitable returns. A combination of Lime + P + inoculation recorded the highest maize (4490 kg/ha, 3470 kg/ha) and soybean (970kglha, 830kglha) grain yields during the first and second seasons, respectively. Sole P treatment gave a higher average nodule number per plant and plant biomass (g), respectively (8 and 21.8) than sole inoculation (4 and 19.2) and sole lime treatments (2 and 16.8) during the first season. Lime application at Z.5 t/ha increased soil pH from 4.9 to 5.58. Increase in soil available P was in the order' of lime> P > inoculation (9.35 > 6.50 > 5.10) mg/kg. Sole lime treatment proved 'to be a more profitable investment for the farmers as it gave. a net benefit of Ksh 89,015.20 with a benefit-cost ratio (BCR) of 2.2. Therefore, integration of lime, inorganic P and inoculation needs to be disseminated among small-scale farmers in western Kenya for improved maize and legume production.
An Analysis of Sesame Crop Value Chain: A Case Study of Kordofan Region, Sudan
(2013-10-17) Ahmed, Shawgi Ali
There is an urgent need to improve production and marketing conditions of small holder farmers in Kordofan region of Sudan in order to alleviate poverty and enhance food security. This study was conducted to determine the profitability of the sesame value chain as one of the viable options that can address the challenges of small holder fanners. This study characterized the sesame value chain from producers to processors in terms of material and information flows as well as theinter-relationships between the actors. In addition, constraints and opportunities in the sesame production and processingwere determined and marketing costs, value added and profit margin distribution among actors in the chain evaluated. A sample size of 150 respondents (farmers) were randomly selected using multistage sampling procedures. Thirty other actors (assemblers, brokers, wholesalers and processors)were traced and interviewed subjectively using purposive sampling procedures. The study used functional analysis, flowcharts and mapping of the current sesame value chain as well as strengths, weaknesses, opportunities and threats (SWOT) analysis and financial analysis to draw results, conclusions and recommendations. The findings revealed that sesame production is constrained by lack of extension services, civil war and conflicts between farmers and livestock keepers over natural resources and scarcityof farming equipment.Oil processors are constrained by high cost and insufficiency of inputs and oil imports. Sesame producers' opportunities in the region include production of good local varieties and favorable growing conditions.Oil processors have the potential to increase oil production and compete with other oils by improving quality and exporting the livestock cake directly to the world market instead of selling it to brokers who then export the product. Traditional oil processors appeared to have higher profits(1 ,297.1 SDG/ton)compared to the industry sesame oil and this was attributed to the high cost of oil that was processed traditionally due to increasing demand for organic products and healthy oils.The resultsalso showed 'thattahania processorswere the winners of the chain in terms of profits with the highest profit share of 2705.5 SDG inany ton of sesame that ,wasprocessed. The commendations includea call for government to intervene by establishing extension services and routes demarcation to reduce the conflicts between farmers and livestock keepers. Policy makers, agricultural banks and existing small scale programs could form partnerships with relevant organizations to provide financial and infrastructural support to expand the scope and effectiveness of the current initiatives to overcome reported obstacles of access to credit.
Analysis of technical efficiency among smallholder rice Farmers in Eastern and Southern Provinces of Rwanda
(Kenyatta University, 2014) Ingabire, Chantal
Since 2004, rice is a priority crop for food security and poverty reduction in Rwanda. The crop was found capable of giving the highest yield in the marshlands compared to other crops and its consumption has been growing over the years, surpassing the domestic supply since the 1980s. In a bid to attain self-sufficiency, the country made remarkable efforts to develop the subsector. These were mainly directed towards the expansion of the area under rice, organisation of farmers' cooperatives and easy access to inputs. Despite these efforts, the country continues to rely on imports and the current productivity of.rice is still very low compared to the potential yield. The failure to reach the expected potential yield suggests a lack of technical efficiency in the production process. This study aimed, at assessing rice producers' technical efficiency as well as its determinants in Ntende and Cyili schemes respectively located in the Eastern and Southern provinces of Rwanda. It used a Stochastic Frontier Analysis (SFA) with the Cobb-Douglas function on a random sample of 185 rice farmers. The results indicated that in Rwanda, the size of land, quantity of pesticides used and involvement of family labour in rice farming activities were the significant determinants of paddy production. The results also showed that the average yield in the sample was 4.81tons per hectare and the mean technical efficiency (TE) was 72% implying that rice farmers were operating below the production frontier. Results showed that if the average .farmer should produce at 100% of TE, hislher average yield should reach to 6.7 tons per hectare. Moreover, if the average farmer is compared to the one having the highest TE in the study sample, results indicates that the former would have reduced the inputs by 23% for the same current output. Regarding the determinants of TE, the age of rice farmers was found positively affecting technical inefficiency which indicated that as farmers become older, the inefficiency effects increase and TE decreases. On the other hand, trainings on rice farming practices and visits of extension agents were found to decrease inefficiency and significantly increase with TE. The implication of the study is that, there is an opportunity to increase paddy production through increased technical efficiency. To achieve this, the study recommends an increased number of extension officers' visits, training of farmers as well as a close follow-up to the older farmers.
The impact of the Girinka one cow per poor family program on household income in Gatsibo District, Rwanda
(2014) Mutarutwa, Nkusi Christian
Low agriculture productivity and arable land distribution is a major challenge in Rwanda. The obvious consequences is that a substantial number of rural families who subsist on agriculture have less than 1ha, and where there is no use of fertilizers and most of that land is not arable which will cause land degradation, poverty and low household income. In the vision 2020, Rwanda intends to move from a low level income country to a middle level economy by 2020. The Girinka program is one of the strategies towards these objectives. Its aim is to give to every poor family one cow that will help the poor families to increase their crop production by using manure, increase their income and their nutrition at the household level and country wide as well. It is against this background that the study evaluates the impact of one cow per poor family or Girinka program on household income in Gatsibo district in Rwanda. The study was an attempt to fill the gap of empirical understanding of the impact of Girinka program that was introduced in 2006 in Rwanda. The study objectives were to analyse the impact of the program on household income, on crop production at the household level and to evaluate the constraints facing the implementation of the program. The study has employed the propensity score matching (PSM) approach to analyze the impact of Girinka program on household income in Gatsibo district, using a cross sectional data of households participating and non-participant in the program, collected using a semi structured questionnaire in the region. The findings have shown that the program has a positive impact on household income and crop production at the household level. The logistic regression of the factors that influence the participation in Girinka program, four factors came out significant which are gender, household size, land size and crop input. The study also showed that according to the response of the participant; that corruption was not a main constrain during the implementation of the program, that follow up of local leaders was a constraint, that lack of information was not constrain, that training of beneficiaries was a constraint. The study also recommended the implementation of the program in other areas out of Rwanda as one of the policies basis for improving poor household livelihood, and this study recommended as well for further research of the impact of the program on milk production in the country.
Economic avaluation of Integrated pest management technology for control of mango fruit flies in Embu County, Kenya
(2014) Kibira, Mary Njeri
Mango is the third most important fruit in Kenya in terms of area and total production. Nutritionally, mango fruit is important for vitamins and mineral provision in the daily diet of Kenyans. As an export crop, mango earns the country foreign exchange, acts as source of food and household income especially for resource poor farmers, contributing to poverty alleviation and achievement of Millennium Development Goal number one. However, mango production and marketing is constrained by several factors, among which pests and disease infestation is major. Among the pests, mango fruit fly present a real challenge to producers and exporters due to losses incurred at the farm level and infested mango rejections at export points. To reduce losses, cost of production and increase the profit at producer level, International Centre of Insect Physiology and Ecology (icipe) developed and implemented an Integrated Pest Management fruit fly control package (IPMFFCP) in Embu County, Kenya. The impact of this intervention, however, had not been evaluated. This study therefore evaluated the impact of this intervention on magnitude of mango rejection due to fruit fly damage, insecticide expenditure and net income from mango production. The study also established households’ perception of the effect of the intervention on human health. The study used survey research design in which a structured questionnaire was administered to 257 randomly selected IPMFFCP participants and non participants from the intervention and control areas. Ordinary Least Square (OLS) regression analysis and Difference-in-difference (DD) method were used to assess the impact of the IPMFFCP on magnitude of mango rejection and insecticide expenditure. Two Stage Least Square (2SLS) analysis and DD were used to evaluate the impact of IPMFFCP on net income from mango production. Descriptive statistics were used to assess the household perception of the effect of IPMFFCP on health. The results indicated that on average IPMFFCP participants had approximately 54.5 percent reduction in magnitude of mango rejection than the non participants. The participants spent approximately 46.3 percent less on insecticide per acre than the non participants and on average received approximately 22.4 percent more net income than the non participants. Results also showed that 78 percent of households perceived the intervention improved human health. The results imply that IPMFFCP participants are better off in terms of magnitude of mango rejection and insecticide expenditure reduction and net income from mango production increment. The study recommends expansion of IPMFFCP intervention to the entire mango growing area in Embu County to improve the farmers’ livelihood through the increased profitability.
Characterization of Virus-Free Sweet Potato (Ipomea Hatata (L) Lam) Landraces Using Morphological and SSR Markers in East Kamagak Location-Homabay County
(Kenyatta University, 2014) onyango, Rosally Anyango
Sweet potato is one of the most important crops for food security and income generation in Kenya. The crop is increasing in importance as adverse climate changes limit crop production in many areas. Understanding the genetic diversity of germplasm of crop species is ofimportance for its rational management and use. Identification of the sweet potato landraces is paramount in addressing food security not only in the study region but elsewhere in the country. Morphological characterization of the accessions facilitates the identification of duplicates and unique traits which is important in the future improvement of the crop having the desired characteristics. The study aimed at identifying sweet potato landraces that have high quality and high consumer acceptance in the area in East Kamagak location of Rachuonyo District, Homabay County .The experiment started with survey and germplasm collection aided by use of questionnaire. The collected germplasm was virus indexed using visual scoring, serological and molecular detection. Six sweet potato landraces from East Kamagak along with six released varieties from Kenya Agricultural Research Institute Njoro were used for the study. The accessions were planted using Randomized Complete Block Design. Planting was done in two sites (Sino and Kachieng). Eighteen qualitative (ground cover, leaf shape, tuber colour.) and Eight quantitative characters (leaf length, vine inter-node length,vineweight, yield of tuber.) were scored one month after planting upto harvesting using the sweet potato descriptors oflnternational Potato Centre (CIP). Harvesting was done at 6 months after planting and tubers dried at 60°C to deterrn ine the dry matter content.The accessions exhibited high morphological diversity in aerial and rootcharacteristics. Analysis of variance showed that out of 24 characters evaluated for morphological characterization, 17 characters were significantly different at p
Effect of farmyard manure and mineral fertilizers on maize yield and soil properties in Huye and Bugesera Districts of Rwanda
(2014) Munyabarenzi, Innocent
Agriculture in Rwanda is today characterized by low agricultural productivity due to soil fertility decline. This is mainly attributed to the mining of nutrients due to continuous cropping without adequate external addition of inputs. The adoption of Integrated Soil Fertility Management (ISFM) technologies such as the combination of organic manure and mineral fertilizers is being taken as one of solutions to this situation. A study was therefore, conducted to investigate the effects of farmyard manure and mineral fertilizers on maize yield response, crop nutrient uptake, nutrient use efficiency and to evaluate changes of bio-chemical soil properties brought about by the treatments applied. The study was conducted at the Research Stations of Rwanda Agriculture Board (RAB), namely, at Rubona in Huye and at Karama in Bugesera Districts in Southern and Eastern provinces of Rwanda,respectively. The experiment was arranged in a randomized complete block design (RCBD) with three factors : nitrogen, phosphorus fertilizers and farmyard manure. Nitrogen and phosphorus fertilizers were applied at three levels, 0, 50 and 100 Kg/ha for nitrogen and 0, 25 and 50 kg/ha for phosphorus while Manure levels were two (0 and 10 tons/ha). Maize was the test crop and was planted in plots measuring 4.5 x 4.5 m with a spacing of 75 x 30 cm. The experiments were replicated three times. Soils samples were analyzed for soil pH, soil organic Carbon, total N, available phosphorus,Potassium, CEC, ECEC, Exchangeable acidity and microbial status of the soil. Maize grains were dried after harvest and weighed at 12.5% moisture content. The data was analyzed by ANOVA using general linear model of SAS software. Regression and correlation were used to establish relationships between measured parameters. The results showed that maize grain yield,1000 grain weight and stover biomass were influenced significantly (P<0.05) by the application of farmyard manure and inorganic fertilizers. The combined applications produced yields which were significantly higher than organic or inorganic alone and the control. The highest grain yields of 8.92 tons ha-1 and 7.11 tons ha-1 were obtained in the combined treatments of farmyard manure with mineral fertilizer at a rate of 100 kg ha-1 N, 50kg ha-1 P mineral fertilizer and 10 tons ha-1 manure at both sites (Rubona and Karama), while the controls recorded the lowest grain yields of 4.61 tons ha-1 and 3.23 tons ha-1 for Rubona and Karama sites,respectively. The combined treatments generally showed significantly higher nutrient uptake and nutrient use efficiency than the sole organic and inorganic fertilizers. In the evaluation of soil properties, total nitrogen, K and pH significantly decreased in plots treated with organic and inorganic fertilizers while soil organic C, available P, Ca, Mg and CEC increased generally in treatments under inorganic plus organic fertilizers. In the case of microbial biomass, there were slight increase for both bacteria and fungi after NP fertilizers and manure combined treatments. In both sites, maize yields responded more to nitrogen fertilizer than P fertilizer, an indication of low nitrogen content in the soils of Rubona and Karama.

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