Theses and Dissertations Collection

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    Pest status of citrus psyllids in relation to citrus greening disease (Huanglongbing) in major citrus growing areas of Tanzania
    (Sokoine University of Agriculture, 2024-05) Ruboha, Joseph Oswald
    The citrus industry is a significant contributor to the global economy, with East African countries like Tanzania playing a crucial role. However, the emergence of Asian citrus greening disease, facilitated by insect vectors such as Diaphorina citri and Trioza erytreae, poses a substantial threat to this sector. This study aims to document the impact of citrus greening and psyllid infestations on Tanzania‘s citrus industry, which results in diminished fruit yield, compromised quality, and economic losses. Field surveys were conducted in major citrus-growing regions in Tanzania, including Ruvuma, Arusha, Morogoro, and Tanga. Data was collected using molecular detection techniques, and the prevalence and severity of Huanglongbing, distribution and abundance of Diaphorina citri and Trioza erytreae were recorded. These factors were then correlated with altitude, temperature variations, and citrus varieties. DNA samples were extracted and analysed using polymerase chain reaction (PCR) to confirm the presence of Huanglongbing in selected samples. The study found regional variations in the distribution and abundance of Diaphorina citri and Trioza erytreae. Altitude significantly influenced psyllid species abundance, with Diaphorina citri decreasing and Trioza erytreae increasing with altitude. The temperature had a weak positive correlation with Diaphorina citri abundance and a moderately negative correlation with Trioza erytreae abundance. Different citrus varieties significantly affected Diaphorina citri abundance, with the ―Late Valencia (Kitenesi)‖ variety having the highest average Diaphorina citri counts per tree. The study also found a negative correlation between altitude and the Disease Severity Index (DSI), suggesting that as altitude increases, the DSI decreases. However, a weak positive correlation was observed between the number of citrus trees in an orchard or backyard and the DSI. Significant variations in Huanglongbing prevalence were observed at both the regional and ward levels. The study concluded that the Mediterranean variety was particularly susceptible to Huanglongbing, while the Valencia, Local variety, Washington navel, and Bitijuma varieties exhibited more resistance. The study also confirmed the presence of Ca. L. asiaticus in symptomatic leaves and the absence of bacteria in asymptomatic leaves using PCR Analysis for pathogen detection. The findings of this study have significant implications for developing region-specific management strategies to protect Tanzania‘s citrus industry, which is vital for food security and rural livelihoods. It is recommended to combine molecular and visual methods to enhance our understanding of the dynamics of Tanzania‘s two crucial citrus psyllid species, Diaphorina citri and Trioza erytreae, reflecting the complex ecological interactions involved. This will aid in the development of effective strategies to mitigate the impact of citrus greening disease.
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    Adapting coffee (Coffea Arabica, L.) production to climate change through types of seedlings and soil fertility management practices in Tanzania
    (Sokoine University of Agriculture, 2024-05) Mbwambo, Suzana Gasper
    In Tanzania, coffee is the second largest traditional export commodity after tobacco, accounting for 24 % of the country‘s total foreign exchange earnings. Average annual production has stagnated at about 50,000 metric tons over the past 35 years. One of the widely held reasons is climate change, manifested by high rainfall variability and decline as well as increase in temperature. Elsewhere different adaptation strategies like use of shade trees, drought tolerant coffee varieties and organic fertilizer have been proposed to deal with the effect of climate change on coffee production. However, climate change adaptation studies for coffee production in Tanzania are largely missing. An overall objective of this work was to develop agronomic techniques for adapting Coffea arabica, L. production to climate change. Specifically, the study aimed to: 1) asses coffee growers‘ perceptions on climate change; 2) asses the relationship between scientific climate change record and production records; 3) evaluate field performance of compact coffee variety under selected propagation methods and soil fertility amendment practices and 4) determine the role of type of seedling and fertilizer management practices in increasing resilient of coffee species to the changing climate. The study was undertaken in the Northern Highland zone (Kilimanjaro and Arusha regions) and Southern Highland zone (Songwe, Mbeya and Ruvuma regions), purposively selected based on the level of Arabica coffee production. First a survey was conducted to examine smallholder farmers‘ perceptions of climate change. The findings indicate that, 163 (67 %) farmers perceived climate change has been taking place in their areas (increase in temperature and decrease in rainfall); the most influential factors in their perception being level of education, farming experience and access to climatic information. Farmers‘ perceptions were also consistent with meteorological data both pointing to significant decline in rainfall and increase in temperature. Smallholder farmers have been responding to climate change through planting shade trees, use of disease-tolerant varieties, soil fertility management, and irrigation practices. A follow- up study was conducted to assess the impact of current climate change on Tanzania‘s Arabica coffee production. The findings reveal minimum temperature has been increasing at a higher rate than the maximum temperature in both zones. Increase in minimum temperature by 1°C during short rains and annual mean temperature resulted in a significant coffee production decrease in Kilimanjaro and Arusha regions by -6,041 and -4,450 tons respectively. Field experiments were also established to evaluate performance of cutting, grafting and seed propagules when combined with 75 g N. P. K tree-1, 37.5 g N. P. K +10 Kg Farmyard manure (FYM) tree-1 and 37.5 g N. P. K +20 Kg FYM tree-1. Two split plot experiments laid out in a Randomized Complete Block Design with three replications were established at the two locations (Lyamungu-Hai district and Burka - Arusha district) based on the existing climatic gradient; cutting- propagated plants resulted into highest yield ranging between 1800- 3600 Kg green coffee ha-1 while grafted-propagated plants had the lowest green coffee yield (600-1700 Kg ha-1.). The fourth study utilized climatic data from Coordinated Regional Climate Downscaling Experiment under Representative Concentration Pathway 4.5 to evaluate the potential of cutting, seed and grafted seedlings in attenuating the effects of climatic conditions using Dynamic Agroforestry Coffee model. During the Near-term period (2026-2056) rainfall will increase in Kilimanjaro region at the range of 0.2-13 % while in Arusha region the increase will be 6.05-13 %. Minimum temperature is expected to increase at higher rate than maximum temperature at the range of 1.4-1.48 °C in Kilimanjaro region and in Arusha region at the range of 1.36-1.64 oC. The use of cutting, seed and grafted propagated coffee plants when combined with FYM will result into 40% 35 % and 10% yield reduction respectively. Specific Leaf Area (SLA) among the three types of seedlings also varied; 28 (cutting), 19 (Seed) and 9 (grafted). Higher SLA observed in cutting-propagated plants may affect coffee production since it is linked to high loss of water in plants. Future higher yield loss was observed with the use of inorganic fertilizer (38%) than FYM (18%) in all the three types of seedlings. Based on the above results, it can be concluded that during the last 40 years, coffee farmers from the Northern and Southern Highlands zone of Tanzania have experienced increase in temperature and decrease in rainfall. Rise in minimum temperature and decline in long rains has significantly affected coffee production in the Northern Highlands zone. Similar to the historical period, minimum temperature is expected to increase at the higher rate than maximum temperature in the Northern Highlands zone during the Near-term period. Integrated nutrients sources are able to provide sufficient nutrients to the three types of seedlings as the recommended rates of inorganic fertilizer. Yield of cutting propagated plants under the age of four years if established at the same time with seeds and grafted propagated plants is significantly higher than that of its counterpart. However, grafted propagated plants are more resilient to climate change. It is therefore recommended that, integrated soil fertility management (37.5 g N.P.K +10 Kg FYM) tree-1 to be used as one of the adaptation strategies because apart from providing nutrients to the coffee plants the package also helps in improving water retention properties of the soil. In addition, seedling distribution should be location specific, with cuttings-propagated plants being distributed in areas with rainfall above 1200 mm year-1. The findings hold significant policy implications for enhancing coffee production in regions affected by climate change. Policymakers should enhance timely and accurate weather information delivery along with developing institutions responsible for education and extension services provision. Multiplication and adoption of improved coffee varieties has to be enhanced and promoted by the policymaker. By promoting adoption of improved coffee varieties policymakers can enhance farmers' adaptive capacity and reduce the vulnerability of coffee production to climate-related risks. Future studies will focus on monitoring the response of three types of seedlings above the age of four years assuming that at a later age coffee tree will have reached its maximum production and so more nutrients and water will be required.
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    Harvest stage and postharvest handling approaches to enhance quality of pepper (Piper nigrum L.) in Morogoro district
    (Sokoine University of Agriculture, Morogoro, Tanzania, 2023-11) Christian Anitha Katushabe
    Pepper (Piper nigrum L.) is an important spice crop whose quality can be affected by harvesting and post- harvesting practices. About 50% postharvest loss of black pepper has been reported in Morogoro district. In order to solve the black pepper quality and postharvest losses, smallholder farmers' harvesting and post harvesting practices were assessed for their effect on quality losses. Specifically, this study aimed to (i) generate baseline socio-economic information on harvest and postharvest handling practices of pepper among smallholder farmers in Morogoro District and (ii) assess the effect of pepper harvesting stages on postharvest quality of three black pepper cultivars commonly grown in Morogoro District. econd study characterized fruit growth and development behaviours of black pepper cultivars grown in Morogoro district. A 4x7 factorial experiment arranged in a Randomized Complete Block Design (RCBD) was used. The third study was carried out to determine the effect of harvesting stages on post-harvest quality of three pepper cultivars grown in the Morogoro district. A 3 x 2 factorial experiment with three replicates arranged in a complete randomized design (CRD) was deployed. Qualitative and Quantitative data collected from five wards of Mkuyuni and Matombo divisions economic information on harvest and post-harvest Ten villages were involved in the study to generate the socio- practices used by farmers. The data were collected using a semi-structured questionnaire, Key Informants (KI), and Focus Group Discussions (FGD). The s iii during the experiments were subjected to Statistical Package for Social Sciences and ANOVA, respectively followed by mean separation for the later based on Turkey's HSD test. The results showed that the majority (86.6%) of the farmers in the study area harvested pepper when at least one berry on a spike turned red. Also, most pepper drying was done in the sun using local mats (86.2%), and stored in polypropylene bags (98.6%). Mould growth was reported as the leading cause of storage postharvest losses (95.75%). Results on fruit growth and development showed that the pepper cultivars grown in Morogoro take 8 to 9 months to reach maturity defined by the presence of at least one ripe berry per inflorescence. The number of well-developed berries per spike and spike length differed significantly (p<0.001) between cultivars. 'Ismailia' had many berries (36.11/spike), followed by 'Babu kubwa' (27.3/spike), 'Babu ndogo' (26.88/spike), and 'Babu kati' (22.25/spike). 'Babu kubwa' had the longest (9.10 cm) spikes followed by 'Babu kati' (7.63 cm), 'Ismailia (6.47 cm), and 'Babu ndogo' (5.36 cm). Berry size and firmness differed significantly (p< 0.001) across cultivars and growth periods. Ismailia had the largest (0.566 cm) and firmest (6.973 kg/mm2) berries compared to other cultivars at mature stage. Berry colour changed significantly (p< 0.001) with stages of development, where berry colour of all cultivars changed from green when young to yellow on the 9th month. These findings can guide farmers in determining the best time to harvest each cultivar. iv Results also indicated significant interactions between harvest stages and cultivars (p< 0.001) on moisture content. Pepper berries harvested at the mature stage had significantly low initial moisture (71.6%) resulting in fewer drying days (5 days). Harvesting pepper at mature stage enhanced quality of black pepper; particularly berry colour, firmness, dry recovery, and moisture content. Farmers should therefore harvest their pepper berries at maturity peak to maximize physical and organoleptic qualities. Studies are suggested on. on quantities and qualities of volatile oils at different growth stages of pepper is recommended.
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    Reproductive efficiency traits and viability of calves of Mpwapwa cattle and their crosses
    (Sokoine University of Agriculture, 1988) Das, Shoshinder Sachindra Manmohan
    Fifteen years data on reproductive traits and viability of calves were analysed. Data were collected from cattle records at Livestock Production Research Institute, Mpwapwa, in Central Tanzania. The reproductive traits studied were age at first calving, calving interval (CI), dry period (DP), days open and conception rate (CR)., The genetic groups in the study were Mpwapwa, F^-crossline and Backcross having 8.0%, 54.0% and 31.0% Bos taurus genetic propor- tion, respectively. The objectives of the study were to evaluate the influence of genetic and environmental factors on reproductive traits and viability of calves, to estimate repeatabilities for reproductive efficiency traits (CI, DP and days open) and to .evaluate the relationship between reproductive traits and milk production traits. Overall mean age
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    Diversity and efficacy of tuta absoluta (meyrick) associated entomopathogenic fungi under different tomato agro- ecological zones of Tanzania
    (Sokoine University of Agriculture, 2023) Magwe, Mwamu Magwe
    Tomato crop is one of the important horticultural vegetables which is used both in consumption and commercially worldwide. Insect pests are the most destructive biotic factors facing tomato production almost in the whole world. Tuta absoluta is a one of the most destructive insect which decrease tomato production and increases production cost in Tanzania and in the whole world and its economic effects globally. The management of T. absoluta by synthetic chemicals is not working properly due to resistance which is developed by of the pest .Many findings by plant researchers from different countries including Africa have been proved that the use of entomopathogenic fungi such as Beauveria bassiana, Metarhizium anisopliae, as biocontrols agent against Tuta absoluta is more efficient compare to the use of synthetic pesticides. In this study a total of twenty four soil samples were collected from tomato farms infested by Tuta absoluta, the soil samples were from different agro ecological zones of Tanzania. Culturing, Morphological, Sequencing data and results obtained showed that ten fungi were entomopathogenic fungi and fourteen were non entomopathogenic fungi among ten entomopathogenic fungi only two spp were related to Tuta absoluta management in tomato production. The entomopathogenic fungi related to Tuta absoluta control were Metarhizium spp and Aspergillus spp. Aspergillus spp is not recommended for Tuta absoluta management in tomato plants because it contains afflatoxin which is toxic to human being but it has high pathogenicity against Tuta absoluta. The pathogenicity of entomopathogenic fungi against Tuta absoluta were tested, against T. absoluta larvae, pupa, and adult stages under conditions of 19.5°C and 50%RH, 30.4°C and 70% RH, respectively, at different conidial concentrations (1.0 × 106, 1.0 × 107 , 1.0 × 108 conidial/ml) in the laboratory for twenty nine days. The factorial experiment design was used where by tomato leaflets from screen house (6 × 7 cm area) were used as experimental units that were dipped into (1.0 × 106 , 1.0 × 107 and 1.0 × 108 conidia/ml) of isolates and control (water containing 0.1% Triton X-100). Treated leaflets were dried at room temperature for elimination of excess water then was placed in Petri dishes (21 cm diameter) lined with wet paper towel and cotton covering the petiole to prevent leaf dehydration. Then, ten (10) T. absoluta larvae were inoculated separately into each of three treated leaflets and control. Each concentration was replicated three times with10 larvae. Treated leaflets were used only once at the beginning of the experiment. After 24 h, when treated leaflets are depleted, treated larvae were fed on fresh untreated leaves. Dead larvae were placed on another Petri dish lined with moist paper towel for re- isolation of fungus. Data of the larvae survival duration, number of dead larvae, number of larvae active (larvae treated but persisted), and number of adults emerged from total treated pupae, number of adult emerged was recorded at interval of 24 h and trials were monitored up to the completion of T. absoluta life cycle and lifespan. Results showed that Metarhizium anisopliae, at all concentration caused high larvae mortality rate (98.2%) followed by Aspergillus spp (71%), larvae mortality rate increased with incubation time and concentration and consequently inhibited pupation and adult emergence within a short time before the completion of the life cycle of Tuta absoluta which is 29 days. Metarhizium anisopliae reduced the life span T. absoluta adult within 5 days of post inoculation at all conidia/ml, other entomopathogenic spp (Penicillium spp, and Cladosporium spp,) were also tested against Tuta absoluta larvae, pupa and adult stages the results recoded lower pathogenicity. Penicillium spp recorded 80% of adult survival at all conidial concentration within the whole incubation time. Geotrichum candidum recorded 100% of adult survived at all conidial concentration after the incubation time. Whereas in control T. absoluta adult survived recorded 100%. This study found that Metarhizium anisopliae has the potential to be used as effective biological control against Tuta absoluta in tomato production especially at larvae stage which is the most destructive stage.
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    Effects of plant based fermented organic fertilizers, compost and poultry manure on tomato plant performance and root knot nematode management
    (Sokoine University of Agriculture, 2023) Mziray Z. S
    Tomato (Solanum lycopersicum L.) is one of the most important vegetable crops produced by small holder farmers in Tanzania. Tomato production under agroecological farming methods employs the use of natural fertilizers, biological pest control and other related approaches that ensures crop production while considering environmental and consumer health safety. Farmers practising these methods in Uponda village, Morogoro reported poor plant performance, presence of root galls and low yield in tomato in a participatory research workshop organised by Sustainable Agriculture Tanzania (SAT), held at Sokoine University of Agriculture (SUA) in December 2019. The problems reported, were associated to poor soil fertility status and root knot nematode infestation. Sustainable Agriculture Tanzania (SAT), among many other related activities, is also researching on organic methods of improving soil fertility in order to assist farmers to attain maximum productivity in sustainable manner. Root Knot Nematode (RKN), have been reported to cause significant yield reduction in tomato and is considered as of high economic importance. The use soil organic amendments in improving soil fertility and controlling root knot nematodes have been well documented. However, limited mineral composition, slow- release rate, high application rates, contamination with undesirable substances, and lack of nutritional consistence have been ongoing challenges on the use of organic fertilizers. This study aimed at evaluating the effects of plant based fermented organic fertilizers (PFOFs) developed following SAT procedures with minor improvements, on tomato growth, yield, fruit size as well as controlling root knot nematode. The improved PFOFs were tithozam (a mixture of fermented moringa, wild sunflower, and comfrey leaves) and z-mix (fermented banana peels, banana male buds and tithozam mixed in equal proportions). The exact preparation process is briefly explained in the methodology part of this work. Experiments in screen house and in open field were established at Sokoine University of Agriculture and World Vegetable Centre, Arusha for the evaluation. Same study was also established as an on-farm experiment at uponda village where the problem was reported, but due to either RKN severity or environmental condition and poor management total crop failure was observed. Treatments were poultry manure, compost manure, z-mix, tithozam and control. Test crop was tomato, variety Tanya with a yield potential of 48-64t/ha. Data were tested for normality using Kolmogorov-smirnov and Shapiro-wilk test, and made approximately normal following data cleaning and transformation (square root and arcsine) prior to data analysis. Analysis of variance (ANOVA) done by GenStat statistical package V.16 (VSN International, UK). Least Significant Difference was used as mean separation test both at p = 5%. Treatments resulted into different levels of effectiveness in improving crop performance and controlling root knot nematodes. Application of fermented organic fertilizers significantly increased tomato plant height (p=0.003), number of leaves (p=0.004), number of flowers (p=0.003), number of fruits and overall tomato yield (p=0.004) as compared to control. These fertilizers also significantly (p<0.001) reduced nematode population, reproduction index, and number of galls in tomato roots. Results obtained showed that, PFOFs had similar effects in improving plant growth, fruit size and yield compared to poultry and compost manure. There was a significant difference among tested organic fertilizers on their control in root knot nematodes in tomato. Nematode galling index differed significantly (p<.001), among tested treatments. A fermented mixture of Tithonia diversifolia, Symphytum officinale and Moringa oleifera mixture, was found to be more effective in controlling nematode. However, further research on its mode of action and optimum application rate is recommended. These findings indicate that, the PFOF formulated by SAT can be of alternative use in areas where the compost, poultry and other organic fertilizers are not available.
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    Optimization of natural management methods against fall armyworm (Spodoptera Frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) in maize crops in Morogoro, Tanzania
    (Sokoine University of Agriculture, 2023) Simon .E
    Fall armyworm (FAW), Spodoptera frugiperda (J.E Smith) is a notorious pestiferous insect with wide host range, high dispersal ability and high fecundity that make it one of the most severe economic pests. It has been restricted to America and in 2016 was reported from various countries in Africa including Tanzania. Objectives of this study were (i) Evaluation of natural management methods against FAW for improved maize productivity. (ii) To evaluate the effectiveness of biopesticides- enhenced push-pull systems against FAW in selected maize cropping systems (iii) To determine the influence of cropping systems and biopesticides on parasitism rate and abundance of Parasitoids of S.frugiperda. A completely randomized design (CRD) with four replications was adopted to determine developmental biology of the FAW using bio pesticides B. thuringiensis (Bt), M. anisopliae and neem seed extract with lower dose of 2 mls, 2mls and (30g) per one litre of water respectively, tested against FAW in the laboratory. Results showed that developmental duration of FAW growth stages differed significantly among treatments. Egg incubation, larval duration, pupa stage duration and the total developmental duration were significantly longer on the biopesticides treated colony compared to untreated groups (p < 0.001). The shortest developmental duration of FAW stages were observed on control colonies at 2.1 ± 0.18, 14.88 ± 0.18, and 27.7 ± 0.34 days for egg, larva and pupa stages respectively. The longest developmental duration was observed in colonies under B. thuringiensis treatment (3.5 ± 0.37 SE, 22.03 ± 0.59 SE, 12.68 ± 0.23 SE and 37.7± 0.54 SE) days for egg, larva and pupa stages respectively. The effectiveness of biopesticides-enhenced push-pull systems against FAW in selected maize cropping systems was evaluated. A factorial experiment with treatment combination of 5 × 2 was used. Factor A included biopesticides with five levels. Factor B cropping system with two levels. Results showed significant (p ˂ 0.001) effects of cropping system and biopesticide application on FAW egg masses, abundance of FAW larvae per plant , percent damaged plant and grain yield of maize crop. However, interaction of biopesticides × sampled weeks and between cropping system × biopesticides × sampled week did not significantly influence egg masses. A total of 777 larval and 2241 egg-larval parasitoid species were collected during the 2020 – 2021 period of this study. To determine the influence of cropping systems and biopesticides on parasitism rate and abundance of Parasitoids of S.frugiperda, factor A included biopesticides with five levels (B. thuringiensis, M.anispoliae, neem seed extract, flubendiamide 480 Sc (positive control) and Maize sole crop (negative control). Factor B cropping system with two levels (Push pull technology and maize sole crop. The results showed significant effect on relative abundance of Cotesia sp (p ˂ 0.001) on plots treated with biopesticides. Results also showed significant effect of parasitism rate and relative abundance of one egg-larval parasitoid specie (C. bifoveolatus) and two larval-parasitoids species (C. luteum and Cotesia sp) (P < 0.05) on cropping system. The results also showed significant effect (P < 0.05) on parasitism rate and percentage relative abundance of one egg-larval parasitoid specie (C. bifoveolatus) and two larval- parasitoids species (C. luteum and Cotesia sp) on interaction between cropping system and biopesticides. The highest mean C. bifoveolatus was observed on maize sole crop cropping system treated with neem seed extract biopesticides and the lowest was observed on maize sole crop cropping system with no any biopesticides application, Also the highest mean of Cotesia sp was observed on Push pull technology (PPT) treated with Bacillus thurigiensis biopesticides and the lowest was observed on PPT treated with Metarhizium anisopliae. Then the highest mean of C. luteum was observed on Push pull technology treated with Bacillus thurigiensis biopesticides and the lowest was observed on PPT treated with flubendamide as negative control. The results also showed significant effects of parasitism rate for Chelonus bifoveolatus and Cotesia sp on interaction between cropping system and biopesticides application, biopesticides and sampling week. The highest mean parasitism rate of C. bifoveolatus was observed on maize sole crop cropping system treated with neem seed extract biopesticides and the lowest was observed on maize sole crop cropping system with no any biopesticides application. The highest mean of Cotesia sp was observed on Push pull technology treated with Bacillus thurigiensis biopesticides and the lowest was observed on PPT treated with Metarhizium anisopliae. No emerged parasitoid species from eggs sampled from plots treated with Flubendiamide. Overall, both biopesticides and push pull technology demonstrated potential natural control methods for the invasive fall armyworm in maize fields in Morogoro Tanzania
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    Assessment of post-harvest losses of mango (mangifera indica l.) in Morogoro region.
    (Sokoine University of Agriculture, 2011) KIMARO, E. S
    High postharvest loss of up to 60 % due to improper postharvest handling practices during the supply chain has been reported in fresh mango fruits in Tanzania The study was conducted to determine mango fruit damages in different stages of the supply chain and develops suitable practices for reduction of postharvest losses during the wholesale market in Morogoro region. Based on farmers/traders practices, postharvest losses of mango fruits at harvesting, transportation and wholesale storage were evaluated. Moreover, an assessment was conducted to compare fruit postharvest losses when ‘tenga’ were loaded with or without separators in between for truck transportation and when fruit ‘tenga’ were stored under the sun, woven polypropylene and black net shades during the wholesale storage. Survey data were analysed using SPSS program based on cross tap method whereas data analysis to compare effect of separators between cartons on fruit losses based on Student t-test (P < 0.05). Data to compare effect of shades on fruit losses were subjected to analysis of variance and treatments mean separation was carried out based on Tukey test (P< 0.05). The total postharvest losses of mango *fruits encountered in all stages along the supply chain was 43.8 % with the main damage features being caused by fruit fly maggots, microbial decay and fruit softening each accounting for 8.65, 11.85 and 20.05 % of the total losses, respectively. Conversely, fruit storage under the shades significantly (P < 0.05) reduced fruit postharvest losses from 31.09% under the sun to 9.31 and 11.34 % under the woven polypropylene and black screen shades, respectively. It is recommended that traders should use separators between ‘tenga’ during long distance mango fruit transportation and store fresh mango fruits under polypropylene shade during the wholesale storage market in order to reduce postharvest losses. Municipal or district authorities are argued to construct cold storage facilities for storing fresh fruits.Furthermore, farmers should disinfect fruits against fruit fly eggs and decay micro organism as a strategy to reduce postharvest losses.
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    Occurrence and farmers’ awareness on sisal bole rot disease in Muheza district, Tanzania
    (Sokoine University of Agriculture, 2023) Meena, Mary Zakayo
    Sisal (Agave sisalana L.) produce the world's most important natural hard fiber and Tanzania is the world's third largest producer of the fiber, accounting for more than 40% of global production. Muheza district is the second largest producer of sisal, after Korogwe district, which is the center of sisal industry in Tanzania and whose production is mainly based on rural estates and smallholders. The crop has adaptive advantages to stress conditions and pests, but bole rot is one of the main disease that causes significant damage to the crop. The disease is often associated with Aspergillus fungi and it has been a burden to the crop since 1930s. To date, there are four Aspergillus species recognized as the causal agents of the disease; A. niger, A. welwitschia, A. brasiliensis and A. tubingensis, but the predominant agent is A. niger. The infection of fungi to sisal plantlets and matured sisal plants results into death of plants, reducing its quality and quantity. In Tanzania, no research has been conducted to assess farmers’ level of awareness neither on sisal bole rot disease or on the assessment of disease incidence and severity in farmers' field. This study aimed at determining farmers’ level of awareness of bole rot disease and disease incidence and severity in farmers’ sisal farms at three wards found in different agro-ecologies in Muheza district. A questionnaire was used in obtaining information from 71 small scale sisal farmers and three sisal estates found in Muheza district. Assessment of disease incidence and severity was conducted at the same wards, where three smallholders and one sisal estate at each ward were randomly selected by systematic sampling. A one hectare farm per small scale farmer and per estate was measured and studied during dry and rainy seasons in the same sisal farms. Majority of sisal farmers (68.92%) had moderate (39-71%) level of awareness of bole rot disease whilst 6.76% of sisal farmers had low (0-38%) level of awareness. The farmers lack in-depth knowledge regarding sisal bole rot disease probably because most of them (89.19%) rely on their fellow sisal farmers’ to obtain information on sisal production and on bole rot disease. More than half (72.9%) of the farmers, their sisal fields were affected by bole rot disease presumably due to the use of infected planting materials. The disease was found in all studied wards at different intensity possibly because of diverse climatic conditions and low altitude predominant in the surveyed wards. Kigombe ward located at low altitude had high disease incidence (36.43%), severity (32.54%) and disease intensity index of (42.40) while Tanganyika ward found in high altitude had low disease incidence (19.09%), severity (12.82%) and disease intensity index of 90.4. The development of bole rot disease was higher during wet season than during dry season in both surveyed wards and Kigombe ward had the highest disease incidence (46.46%) and severity (40.24%) probably because it is found in low land with flat areas which get flooded during heavy rainfall, a conducive environment for fungal infection, growth and reproduction. It was noted that all sisal growers (100%) still use unhealthy sisal planting materials namely suckers from previous crop to raise their new crop possibly due to lack of bole rot awareness and money. Education is important for improving farmers’ awareness regarding sisal production and management of bole rot disease. A prepared comprehensive training module on sisal production practices with management practices of bole rot disease should be introduced to sisal farmers as a way of increasing their awareness on sisal production and management of bole rot disease. Efforts are needed to improve farmers to access healthy planting materials through effective distribution. Nurseries for the production of healthy sisal seedlings should be set up in each ward to facilitate farmer access and reduce transport costs. However, further studies to assessing farmers’ level of awareness on bole rot disease and on the determination of disease intensity should be done in this and other sisal growing areas in Tanzania.
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    Optimization of natural management methods against fall armyworm (Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) in maize crops in Morogoro, Tanzania
    (Sokoine University of Agriculture, 2023) Simon, Erick
    Fall armyworm (FAW), Spodoptera frugiperda (J.E Smith) is a notorious pestiferous insect with wide host range, high dispersal ability and high fecundity that make it one of the most severe economic pests. It has been restricted to America and in 2016 was reported from various countries in Africa including Tanzania. Objectives of this study were (i) Evaluation of natural management methods against FAW for improved maize productivity. (ii) To evaluate the effectiveness of biopesticides-enhanced push-pull systems against FAW in selected maize cropping systems (iii) To determine the influence of cropping systems and biopesticides on parasitism rate and abundance of Parasitoids of S.frugiperda. A completely randomized design (CRD) with four replications was adopted to determine developmental biology of the FAW using bio pesticides B. thuringiensis (Bt), M. anisopliae and neem seed extract with lower dose of 2 mls, 2mls and (30g) per one litre of water respectively, tested against FAW in the laboratory. Results showed that developmental duration of FAW growth stages differed significantly among treatments. Egg incubation, larval duration, pupa stage duration and the total developmental duration were significantly longer on the biopesticides treated colony compared to untreated groups (p < 0.001). The shortest developmental duration of FAW stages were observed on control colonies at 2.1 ± 0.18, 14.88 ± 0.18, and 27.7 ± 0.34 days for egg, larva and pupa stages respectively. The longest developmental duration was observed in colonies under B. thuringiensis treatment (3.5 ± 0.37 SE, 22.03 ± 0.59 SE, 12.68 ± 0.23 SE and 37.7± 0.54 SE) days for egg, larva and pupa stages respectively. The effectiveness of biopesticides-enhanced push-pull systems against FAW in selected maize cropping systems was evaluated. A factorial experiment with treatment combination of 5 × 2 was used. Factor A included biopesticides with five levels. Factor B cropping system with two levels. Results showed significant (p ˂ 0.001) effects of cropping system and biopesticide application on FAW egg masses, abundance of FAW larvae per plant , percent damaged plant and grain yield of maize crop. However, interaction of biopesticides × sampled weeks and between cropping system × biopesticides × sampled week did not significantly influence egg masses. A total of 777 larval and 2241 egg-larval parasitoid species were collected during the 2020 – 2021 period of this study. To determine the influence of cropping systems and biopesticides on parasitism rate and abundance of Parasitoids of S.frugiperda, factor A included biopesticides with five levels (B. thuringiensis, M.anisopliae, neem seed extract, flubendiamide 480 Sc (positive control) and Maize sole crop (negative control). Factor B cropping system with two levels (Push pull technology and maize sole crop. The results showed significant effect on relative abundance of Cotesia sp (p ˂ 0.001) on plots treated with biopesticides. Results also showed significant effect of parasitism rate and relative abundance of one egg-larval parasitoid specie (Cbi foveolatus) and two larval-parasitoids species (C. luteum and Cotesia sp) (P < 0.05) on cropping system. The results also showed significant effect (P < 0.05) on parasitism rate and percentage relative abundance of one egg-larval parasitoid specie (Cbi foveolatus) and two larval- parasitoids species (C. luteum and Cotesia sp) on interaction between cropping system and biopesticides. The highest mean Ci foveolatus was observed on maize sole crop cropping system treated with neem seed extract biopesticides and the lowest was observed on maize sole crop cropping system with no any biopesticides application, Also the highest mean of Cotesia sp was observed on Push pull technology (PPT) treated with Bacillus thuringiensis biopesticides and the lowest was observed on PPT treated with Metarhizium anisopliae. Then the highest mean of C. luteum was observed on Push pull technology treated with Bacillus thuringiensis biopesticides and the lowest was observed on PPT treated with flubendiamide as negative control. The results also showed significant effects of parasitism rate for Chelonus bifoveolatus and Cotesia sp on interaction between cropping system and biopesticides application, biopesticides and sampling week. The highest mean parasitism rate of Cbi foveolatus was observed on maize sole crop cropping system treated with neem seed extract biopesticides and the lowest was observed on maize sole crop cropping system with no any biopesticides application. The highest mean of Cotesia sp was observed on Push pull technology treated with Bacillus thuringiensis biopesticides and the lowest was observed on PPT treated with Metarhizium anisopliae. No emerged parasitoid species from eggs sampled from plots treated with Flubendiamide. Overall, both biopesticides and push pull technology demonstrated potential natural control methods for the invasive fall armyworm in maize fields in Morogoro Tanzania.
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    Bean bruchid resistance and genetic diversity of bruchid ecotypes from bean growing regions of Tanzania
    (Sokoine University of Agriculture, 2022) Mayunga Edina
    Bean bruchids Zabrotes subfasciatus and Acanthoscelides obtectus are the serious pests which cause serious damage to the stored beans. Damage is directly related to the time of bean storage, the longer storage time the greater the damage. Host plant resistance is a profitable and a safe alternative to control bruchids in common bean and is associated with biochemical, morphological, and molecular traits. These traits affect insect growth and development and in that way, reduce the losses by the pests. The aim of first objective was to evaluate the damage level of bruchids in resistant (AO-1012-29-3-3A) and susceptible (Njano gololi) bean genotypes associated with biotype variation. Bean bruchids were collected from different bean growing regions Songwe (Vwawa), Kilimanjaro (Mungushi), Karatu (Rhotia), Morogoro (SUA) and Arusha (Kimyaki) in Tanzania, then transferred to the laboratory for inoculation. . Experiment was conducted using a Completely Randomized Design (CRD) with a 2 x 5 factorial scheme, two bean cultivars (AO-1012-29-3-3A and Njano gololi), five bruchids ecotypes for each A. obtectus and Z. subfasciatus and 3 replications. The results of this study have reported that each bean bruchids from a specific region showed a significant difference at prob. = 0.001 on beans infestation. AO-1012-29-3-3A and Njano showed different results on the resistance to bean bruchids. It was observed that AO-1012-29-3-3A line was resistant to bruchids collected from many regions by experiencing less damage and Njano gololi was observed to have high population of emerged bean bruchids, high percentage weight loss, high Susceptibility index and severity hence susceptible. The purpose of second objective was to determine phenotypic characteristics of the emerged F 1 bruchid ecotypes resulted from crossing resistant (AO-1012-29-3-3A) and susceptible (Njano gololi) bean genotypes. To examine whether these traits are host induced or genetically determined. Resistant genotype was used to assess whether host-race morphological differences are genetically determined or due to phenotypic plasticity. There was significant difference in size of F 1 bruchids emerging from resistant genotype (AO-1012-29-3-3A) and susceptible genotype (Njano gololi). The results showed that the morphological change of F 1 bruchids from AO-1012-29-3-3A was due to phenotypic plasticity since morphological changes occurred due to feeding on resistant genotypes (environment factor). The purpose of third objective was to identify the genetic diversity of bean bruchid weevils (Acanthoscelides obtectus and Zabrotes subfasciatus) in bean producing regions in Tanzania using molecular taxonomy (12S rRNA and COI marker). The results obtained did not show genetic diversity (100% identity) of Acanthoscelides obtectus present in Tanzania. For Zabrotes subfasciatus some variations was observed (80.2% identity). The genetic diversity was observed between Acanthoscelides obtectus and Zabrotes subfasciatus in which there was difference in some sequence alignment. Better knowledge of bruchids diversity present in Tanzania will help breeders and farmers to propose effective control methods with impact on environmental changes.
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    Optimization of natural management methods against fall armyworm (Spodoptera frugiperda (j.e. smith) (lepidoptera: noctuidae) in maize crops in Morogoro, Tanzania
    (Sokoine University of Agriculture, 2023) Erick Simon
    Fall armyworm (FAW), Spodoptera frugiperda (J.E Smith) is a notorious pestiferous insect with wide host range, high dispersal ability and high fecundity that make it one of the most severe economic pests. It has been restricted to America and in 2016 was reported from various countries in Africa including Tanzania. Objectives of this study were (i) Evaluation of natural management methods against FAW for improved maize productivity. (ii) To evaluate the effectiveness of biopesticides- enhenced push-pull systems against FAW in selected maize cropping systems (iii) To determine the influence of cropping systems and biopesticides on parasitism rate and abundance of Parasitoids of S.frugiperda. A completely randomized design (CRD) with four replications was adopted to determine developmental biology of the FAW using bio pesticides B. thuringiensis (Bt), M. anisopliae and neem seed extract with lower dose of 2 mls, 2mls and (30g) per one litre of water respectively, tested against FAW in the laboratory. Results showed that developmental duration of FAW growth stages differed significantly among treatments. Egg incubation, larval duration, pupa stage duration and the total developmental duration were significantly longer on the biopesticides treated colony compared to untreated groups (p < 0.001). The shortest developmental duration of FAW stages were observed on control colonies at 2.1 ± 0.18, 14.88 ± 0.18, and 27.7 ± 0.34 days for egg, larva and pupa stages respectively. The longest developmental duration was observed in colonies under B. thuringiensis treatment (3.5 ± 0.37 SE, 22.03 ± 0.59 SE, 12.68 ± 0.23 SE and 37.7± 0.54 SE) days for egg, larva and pupa stages respectively. The effectiveness of biopesticides-enhenced push-pull systems against FAW in selected maize cropping systems was evaluated. A factorial experiment with treatment combination of 5 × 2 was used. Factor A included biopesticides with five levels. Factor B cropping system with two levels. Results showed significant (p ˂ 0.001) effects of cropping system and biopesticide application on FAW egg masses, abundance of FAW larvae per plant , percent damaged plant and grain yield of maize crop. However, interaction of biopesticides × sampled weeks and between cropping system × biopesticides × sampled week did not significantly influence egg masses. A total of 777 larval and 2241 egg-larval parasitoid species were collected during the 2020 – 2021 period of this study. To determine the influence of cropping systems and biopesticides on parasitism rate and abundance of Parasitoids of S.frugiperda, factor A included biopesticides with five levels (B. thuringiensis, M.anispoliae, neem seed extract, flubendiamide 480 Sc (positive control) and Maize sole crop (negative control). Factor B cropping system with two levels (Push pull technology and maize sole crop. The results showed significant effect on relative abundance of Cotesia sp (p ˂ 0.001) on plots treated with biopesticides. Results also showed significant effect of parasitism rate and relative abundance of one egg-larval parasitoid specie (C. bifoveolatus) and two larval-parasitoids species (C. luteum and Cotesia sp) (P < 0.05) on cropping system. The results also showed significant effect (P < 0.05) on parasitism rate and percentage relative abundance of one egg-larval parasitoid specie (C. bifoveolatus) and two larval- parasitoids species (C. luteum and Cotesia sp) on interaction between cropping system and biopesticides. The highest mean C. bifoveolatus was observed on maize sole crop cropping system treated with neem seed extract biopesticides and the lowest was observed on maize sole crop cropping system with no any biopesticides application, Also the highest mean of Cotesia sp was observed on Push pull technology (PPT) treated with Bacillus thurigiensis biopesticides and the lowest was observed on PPT treated with Metarhizium anisopliae. Then the highest mean of C. luteum was observed on Push pull technology treated with Bacillus thurigiensis biopesticides and the lowest was observed on PPT treated with flubendamide as negative control. The results also showed significant effects of parasitism rate for Chelonus bifoveolatus and Cotesia sp on interaction between cropping system and biopesticides application, biopesticides and sampling week. The highest mean parasitism rate of C. bifoveolatus was observed on maize sole crop cropping system treated with neem seed extract biopesticides and the lowest was observed on maize sole crop cropping system with no any biopesticides application. The highest mean of Cotesia sp was observed on Push pull technology treated with Bacillus thurigiensis biopesticides and the lowest was observed on PPT treated with Metarhizium anisopliae. No emerged parasitoid species from eggs sampled from plots treated with Flubendiamide. Overall, both biopesticides and push pull technology demonstrated potential natural control methods for the invasive fall armyworm in maize fields in Morogoro Tanzania.
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    Effect of pruning on yield and quality of selected indeterminate tomato (solanum lycopersicon L.) Lnes
    (Sokoine University of Agriculture., 2011) Mbonihankuye, Cyrille
    Preliminary evaluations at Sokoine University of Agriculture have shown that indeterminate tomato breeding lines are tolerant to late blight and produce high yield of large fruits. These large fruits are least accepted by the local consumers in Tanzania. Pruning system has been reported to regulate tomato fruit size, overall yield performance and foliar disease incidence. A study to evaluate the effect of pruning levels (non pruning, single stem, two stems and three stems) on yield, quality and late blight disease incidence of five breeding lines of indeterminate tomato and one commercial variety was conducted from November 2009 to March 2010 at the Horticulture Unit of Sokoine University of Agriculture, Morogoro, Tanzania. The experiment was laid in a split-plot in a randomized complete block design with three replications. The collected data were subjected to analysis of variance (ANOVA), mean separation was done based on Student-Newman- Keuls using statistical software COSTAT6.4 (P<5%). Results showed that two stem pruned plants gave the highest number of marketable fruits per plant. The highest number of non marketable tomato fruits (damaged by pests, cracked or rotten) per hectare were observed in unpruned plants. Tomato lines differed in their performance, with the longest period of harvest, many flowers, higher percentage of fruit-set, the highest yield, high number of marketable fruits observed in lines P20-03 and SI 86-2(07) probably as a result of their genetic characteristic. Non pruned plants were more attacked by late blight disease whereas single and two stem plants were least affected by late blight. It is concluded that, the large fruit size of the new tomato breeding lines can be reduced to meet consumer’s needs without reducing yield by two and three stem pruning in lines P20-03 and SI 86- 2(07). It is therefore recommended that creation of awareness through demonstration trials is needed for further promotion of these new lines combined with two and three stem pruning in order to improve tomato production in terms of quantity and quality.
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    Livelihood struggle and environmental degradation in Tanzania: a case of Morogoro rural district
    (Sokoine University of Agriculture, 2007) Mwangoka, Suzana Godwin
    The study was conducted in Morogoro Rural District Tanzania. It aimed at assessing the impact of livelihood struggle on the environment to obtain information for researchers. planners and decision makers to work upon. Six villages were purposively chosen to represent villages affected environmentally through livelihood struggle activities. A cross sectional design using household, stakeholders' questionnaires, participatory rural appraisal and focus group discussions were used to collect information intended to answer the main objective of the study. Cross tabulations and chi-square test were used to compare the relationship between study variables. Results showed that socio-economic activities undertaken in the area are small scale crop farming (practiced by 84.5% of the respondents), wage labour employments (4.8%), livestock keeping (4.2%), mining (2.8%), both farming and poultry keeping (1.7%) and petty trading in mining sites (1.2%). Farming near river banks (70% of respondents), cultivation on slopes (20%). continuous cultivation (5%). both poor mining and livestock keeping (4%) and shifting cultivation (1%) were found to be common activities that lead to environmental degradation. Out of all respondents. 17% grow trees and filled mined pits in degraded areas, while 83% took no precautions. Relationship between socio-economic activities and environmental degradation was mainly manifested through drying of water sources and water pollution. Results also showed that despite the ongoing livelihood activities that cause environmental degradation, majority of the respondents (87%) were aware of environmental degradation compared to 13 % of the respondents that were not. It was concluded that communities undertake such environmentally unfriendly activities because they have limited alternative means of livelihood because they have to rely on the available natural resources. It was recommended that a multi-sectoral land use planning strategy should be implemented for sustainable development through natural resources management and equal opportunity to all sectors competing for land and other resources.
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    Effect of conservation agriculture practices on maize yields and environmental conservation on steep slopes of Southern Uluguru mountains
    (Sokoine University of Agriculture, 2015) Lushinge, Shida
    This study was conducted at Kolero village, on the footslopes of southern Uluguru Mountains in order to investigate the effectiveness of different Conservation Agriculture practices on soil moisture retention its implication on maize production and environmental conservation on the steep slopes. Two factors (tillage practice and cover crop) each at three levels were combined to form a 3 x 3 factorial experiment and tested in Randomized Complete Block Design (RCBD) with three replications each. Levels for Tillage were shallow tillage, zero tillage and strip tillage and those for cover crop were slash and burn, lablab and cowpea. Moisture readings were taken at 0 - 30 cm, 30 - 60 cm and 60 - 90 cm soil depths. Data were analysed using GenStat Software 14th Edition. Results showed that there were significant differences among treatments on moisture retention at soil depth at 60 - 90 cm. Moisture retained within 0-30 cm, 30 - 60 cm and 60 - 90 cm ranged from 13.23% - 15.87%, 18.06% - 19.01% and 14.63% - 15.71%, respectively. There were significant differences (p<0.05) among treatments on maize yield, biomass produced and percentage of cover crop development. Conventional practice had high maize yield (4.5 t/ha) compared to the tested CA practices. Cowpea showed to be a good cover crop when combined with strip tillage, as it resulted in small reduction in maize yield (5%) when compared with conventional practice. Lablab provided good percentage cover later in the growing season than at the beginning. There was a little improvement on soil chemical properties caused by incorporating minimum tillage and cover crops as CA practices on maize production. Results showed that there is a need to incorporate maize and other crop residues for effective moisture retention.
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    Plant structure in relation to ease of physical breakdown in the mouth and rumen
    (University of Wales, 1993-09) Mtengeti, Ephraim Joseph
    Grassland species were grown in the field and glasshouse and research was carried out for two years to investigate plant vascular structure in relation to physical breakdown in the mouth and rumen. Plant part morphology, vascular structural proportion and arrangement, fresh plant diet eating rate by sheep and particle breakdown characteristics were recorded. Anatomical differences, especially vascular tissue arrangement, appeared to be a major cause of the differences in intake rate between legumes and grasses. Four legumes did not differ significantly in terms of intake rate but differed significantly in terms of the proportion of vascular tissues, neutral detergent fibre content and digestibility. Tropical grasses had a higher proportion of vascular tissues, higher neutral detergent fibre content, lower digestibility, lower intake rate and were chewed into smaller particles than temperate grasses. Legumes were eaten faster and had larger particles after chewing than grasses. Legume and grass particles had a similar number of perforations or ruptures per particle. Legume leaf petiole and stem particles were longer than leaflet particles and increased the overall mean particle length of the chewed material. Petioles and stems are, therefore, important in legume particle size reduction in the mouth and rumen. Regardless of grass species, the veins of the leaf sheaths were more widely spaced than those in leaf blades, but the two plant parts were chewed to a similar particle size. Despite having a high proportion of stem and neutral detergent fibre, lucerne and spurrey were eaten quickly, showing the advantage, in respect of intake rate, of having thin pliable and/or fragile stems. The results of the present project indicate that the physical structure of plants, especially the arrangement of the vascular tissue, and plant morphology have great influence on the physical breakdown of the plants in the mouth and rumen.
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    Impact of varieties and delinting methods on growth, yield and quality of cotton (GOSSYPIUMIIIRSUTUM L.) lint and seed
    (Sokoine University of Agriculture, 2006) Msemo, Eliphas Abrahams Yoazar
    Two experiments were conducted at Agricultural Research Institute Ukiriguru, Mwanza, Tanzania to evaluate the effectiveness of cotton varieties and cottonseed-delinting methods on seed quality, growth, yield and quality of lint and seeds. A completely randomised design (CRD) experiment with four replications to assess cottonseeds quality of three cotton varieties (UK77, UK 82 and UK 91) dclintcd mechanically, by using concentrated (98%) sulphuric acid, dilute (49%) sulphuric acid, Tanzania Cotton Lint and Seed Board [TCLSB] sulphuric acid methods and non-delinted seeds applied as a control giving 15 treatment-combinations was conducted. A randomised complete block design (RCBD), with a split-plot field experiment replicated four times with similar treatment-combinations was conducted to determine their effectiveness on cotton crop growth, yield and quality of lint and seeds. The crop was sown at two-rows, 45 cm apart on either side of a 1.5 m ridge with six seeds per hill 45 cm apart, which were later on thinned to two plants 35 days after planting. Data on seed quality, crop growth, yield, lint and fibre quality were collected and analysed. Laboratory experimental results obtained indicated that seed quality (germination percentage) was significantly affected (P <0.001) by the treatments applied; best quality being from the use of concentrated (98%) sulphuric acid. Growth and development variables were not significantly affected (P <0.05) by the treatments used, yield of seed­ cotton and lint were significantly affected by the cotton-varieties at P <0.05 and the interaction effects (P <0.001) of varieties x delinting methods used. Fibre quality was also significantly affected (P <0.05) by the treatment interaction-effects. Based on these results, for best cotton-seed quality, optimum seed-cotton and lint yield, and fibre quality, farmers should use delinted UK 91 and UK 77 cotton-seed varieties by using concentred (98%) sulphuric acid or TCLSB sulphuric acid methods.
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    The physiological performance of varietal mixtures of the common bean (phaseolus vulgaris, l.) grown under broadcast or conventional planting methods
    (Sokoine University of Agriculture, 2002) Mhile, Oscar Mwashiuya
    A study was carried out at Mbozi and Morogoro Districts of Tanzania during the 2000/2001 cropping seasons. The main objective was'to determine the relationship between growth characteristics and economic yield of varietal mixtures of common beans grown by broadcast or row planting methods. The experiment was a split plot in randomized complete block design (RCBD) with four replications. Different varieties were used at each location, which formed the main plots. Five varieties at the highland (kabanima. U-94. U-90. kigoma. and mixed variety), and four at the lowland (rojo. SUA 90. kablankeli. and mixed variety) were used. At each location one variety was a mixture of those varieties. The subplots were the planting methods. The results indicate that broadcast planting increased leaf area index (LAI). intercepted photosynthetically active radiation (PAR), crop growth rate (CGR). total dry matter (TDM), plant height, pods plant’1, and seeds pod’1, while row planting increased radiation use efficiency (RUE). TDM partitioning, branches per plant, and 100-seed weight. Among varieties at the highland location, the mixed variety produced the highest TDM. branches per plant, and grain yield m’?. Kigoma (indeterminate) was the tallest and accumulated the greatest PAR. Kabanima (determinate) was the shortest and performed poorly in dry matter (DM) accumulation, development of LAI. cumulative PAR. CGR. and RUE. At the lowland location, the mixed variety was superior in LAL light interception, and pods per plant. The mixed variety was the tallest and SUA-90 the shortest. At the highland location, row planting had higher grain yield than broadcast planting as compared to the lowland location. The differences were attributed to greater TDM and branches per plant at the highland location, and RUE and pods plant’1 at the lowland location. It is concluded that physiologically there was no difference between broadcast and row planting of common beans. Thus, farmers my use either of the methods. Also mixed varieties could be recommended under- subsistence agriculture but could be economically unsuitable where marketing require quality pure varieties for better prices.
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    Impact of varieties and delinting methods on growth, yield and quality of cotton (Gossypium Hirsutum L.) lint and seed
    (Sokoine University of Agriculture, 2006) Msemo, Eliphas Abrahams Yoazar
    Two experiments were conducted at Agricultural Research Institute Ukiriguru, Mwanza, Tanzania to evaluate the effectiveness of cotton varieties and cottonseed-delinting methods on seed quality, growth, yield and quality of lint and seeds. A completely randomised design (CRD) experiment with four replications to assess cottonseeds quality of three cotton varieties (UK77, UK 82 and UK 91) delinted mechanically, by using concentrated (98%) sulphuric acid, dilute (49%) sulphuric acid, Tanzania Cotton Lint and Seed Board [TCLSB] sulphuric acid methods and non-delinted seeds applied as a control giving 15 treatment-combinations was conducted. A randomised complete block design (RCBD), with a split-plot field experiment replicated four times with similar treatment-combinations was conducted to determine their effectiveness on cotton crop growth, yield and quality of lint and seeds. The crop was sown at two-rows, 45 cm apart on either side of a 1.5 m ridge with six seeds per hill 45 cm apart, which were later on thinned to two plants 35 days after planting. Data on seed quality, crop growth, yield, lint and fibre quality were collected and analysed. Laboratory experimental results obtained indicated that seed quality (germination percentage) was significantly affected (P <0.001) by the treatments applied; best quality being from the use of concentrated (98%) sulphuric acid. Growth and development variables were not significantly affected (P <0.05) by the treatments used, yield of seed­ cotton and lint were significantly affected by the cotton-varieties at P <0.05 and the interaction effects (P <0.001) of varieties x delinting methods used. Fibre quality was also significantly affected (P <0.05) by the treatment interaction-effects. Based on these results, for best cotton-seed quality, optimum seed-cotton and lint yield, and fibre quality, farmers should use delinted UK 91 and UK 77 cotton-seed varieties by using concentred (98%) sulphuric acid or TCLSB sulphuric acid methods.
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    Detection, characterization and control of Xanthomonas spp., causal agents of bacterial leaf spot of tomato in Tanzania.
    (University of Copenhagen, 2011) Mbega, Ernest Rashid
    Tomato (Solatium lycopersicum L.) is one of the most important cash and dietary vegetable crops grown by small and medium scale farmers in Tanzania. Demand for fresh market and canning for tomato is high, however, the national average yield remains low mainly due to insect pests and diseases. Bacterial leaf spot (BLS) caused by Xanthomonas spp. is considered to be a devastating disease of tomato worldwide and reported to cause yield losses of up to 45% in Tanzania. Diagnosis of BLS disease and differentiation of the different species and strains of the pathogen involved is usually complicated due to similarities of symptoms expression in tomato plants. The problem is further complicated by presence of other bacterial pathogens associated with tomato, such as Pseudomonas spp., which can induce similar leaf spot symptoms. The BLS disease management in Tanzania has been primarily limited to foliar applications with copper based compounds. However, their efficacy can be limited due to inefficient control once disease symptoms are observed, the rapid development of pathogen resistance to these compounds, risk of polluting the environment, lack of available resistance in comercial cultivars, and sometimes unavailability of suitable commercial products to small scale farmers. document the presence of the causal agents of BLS in seed and plant material in Tanzania develop and apply a PCR based tool for detection of xanthomonads associated with BLS of tomato and evaluate plant extracts and essential oils applied as seed treatment in order to provide an alternative to chemical management of BLS. Therefore, the main focus of the present PhD study was to: To document the presence of the causal agents of BLS in tomato in Tanzania, two surveys were conducted in the Northern, Central and South Highlands of Tanzania between 2008 - 2010. The first survey was conducted in May-July 2008 and aimed at assessing the identity, genetic relationship and pathogenic potential of bacterial leaf spot-causing xanthomonads (BLSX) and other yellow pigmented, Xanthomonas-Vike bacteria (XLB) in tomato seeds from 52 samples of 15 cultivars collected from 45 locations. Characterisation of the BLSX and XLB isolates was based on morphological characteristics on semi-selective agar substrates. Biolog identification system, 16S rRNA sequence analysis and pathogenicity tests on tomato and sweet pepper plants. The