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    Microsatellite analysis of common bean (Phaseolus vulgaris L.) genotypes in Tanzania for diversity in seed iron and zinc micronutrients
    (Greener Journal of Plant breeding and Crop Science, 2023-02-15) Yanda, Focus Edson; Tryphone, George Muhamba
    Common bean (Phaseolus vulgaris L.) grain has big dietary role in supplying protein, energy, vitamins, dietary fibre and micronutrients for millions of people worldwide. In Tanzania, reports have shown existence of Fe and Zn micronutrient variabilities among the common bean genotypes. Eighty-four (84) genotypes were collected to study such variability by seed biochemical and leaf molecular marker analysis. The analyses revealed significant (p < 0.001) genetic variability for seed Zn and Fe nutrient contents. Highest seed Fe content was 118 ppm for genotype Kashiransoni and for seed Zn was 51.81 ppm for Imponzo 5 genotype (both were collected from NPGRC). With seven (7) SSR primers associated with Fe and Zn traits, genetic diversity was evaluated. A marker BM154 scored PIC value 0.967 mean while marker BM160 had a lowest PIC score of 0.899. Using an estimated genetic similarity value, two main clusters with sub clusters in the dendrogram were developed. To corroborate the UPGMA analysis results, a Principal Coordinate Analysis (PCoA) was performed and displayed outputs into scattered plot presentation. For Fe micronutrient improvement purposes, Inula was proposed to be crossed with Kashiransoni while Roba with Imponzo 5 for Zn micronutrient improvement. Selection was based on both concentrations of nutrients for each genotype and their genetic similarity distances.
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    The effect of potyvirus resistance loci from the maize inbred line Oh1VI on development of maize lethal necrosis (MLN)
    (Greener Journal of Agricultural Sciences, 2021-07-31) Bulegeya, Victoria B.; Jones, Mark W.; Muhamba, Tryphone G.; Das, Biswanath; Thomison, Peter R.; Francis, David M.; Redinbaugh, Margaret. G.
    Maize lethal necrosis (MLN), a viral disease currently affecting corn in East and Central Africa is caused by a combined infection of Maize chlorotic mottle virus (MCMV) and any maize infecting potyvirus. Most of African maize germplasm is susceptible to the disease and there are no known sources of resistance. Recombinant inbred lines (RIL) derived from Oh1VI, a line known for multi-virus resistance with different QTL for potyvirus resistance on chromosome 3, 6 and 10 were selected and screened against MLN under artificial inoculation and natural infestation. Differences were observed among genotypes and QTL groups at P=0.05 in all experiments except under field inoculation. Genotypes with QTL combination of 3, 6 and 10 had at least 20% reduction in MLN symptoms compared to a susceptible check. These results provide useful baseline information on utilization of potyvirus resistance genes for MLN resistance and control in Sub Saharan Africa.
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    Effects of pre-harvest application of hexanal formulation on losses and quality of tomato (Solanum lycopersicum Mill)
    (Tanzania Journal of Agricultural Sciences, 2020) Jaspa, S; Msogoya, T.; Tryphone, G.; Mtui, H .D.; Baltazari, A.; Kudra, A.; Mwatawala. M. W.
    The study was conducted to determine the effects of field application of enhanced freshness formulation (EFF) on pre-harvest losses and tomato quality. The parameters assessed include pest defects on fruits, marketable and percentage non-marketable fruit, fruit firmness, and fruit weight. Three popular open pollinated varieties grown in Tanzania namely, Mwanga, Rio Grande, and Tanya were used. The experiment was laid out as Completely Randomized Design in a 4 x 4 x 3 factorial arrangement. Three factors, EFF concentrations, time of EFF application prior to the harvest, and tomato variety were evaluated. EFF concentrations of 0.01, 0.02, 0.04% m/v were tested. Untreated plots were included as control. The time of application was 7, 14, 21, and 28 days prior to the harvest. The results showed that pre-harvest application of EFF at 0.01 percent reduced percent non-marketable tomato fruit of Mwanga, Rio Grande, and Tanya cultivars by 28.99, 26.98 and 37.17 percent, respectively compared with the control. Moreover, pest defects were reduced by 29.45, 24.51, and 27.45 percent for Mwanga, Rio Grande, and Tanya, respectively over the control. Furthermore, fruit firmness was increased by 7.69 N/mm2, 6.33 N/mm2 and 5.98 N/mm2 compared with the control for tomato cv. Mwanga, Rio Grande, and Tanya, respectively
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    Inheritance of Angular Leaf Spot [Phaeoisariopsis griseola (Sacc.) Ferr] Resistance in Common Bean (Phaseolus vulgaris L.) Population Developed from Kablanketi Mexico 54
    (Journal of Agricultural Science and Technology, 2012-07-20) Tryphone, George Muhamba; Chilagane, Luseko Amos; Kusolwa, Paul Mbogo; Nchimbi-Msolla, Susan
    The genetic resistance to angular leaf spot (ALS) caused by Phaeoisariopsis griseola in the common bean cultivar Mexico 54 was investigated on disease reactions in parental, F1, F2 and backcross generations derived from crosses between a resistant cultivar Mexico 54 and a susceptible cultivar Kablanketi under screen house conditions. The heritability (h2) estimate was as high as 0.719 indicating a successful transfer of ALS resistance among progenies and thus selection can be performed in early generation. High heritability coupled with high expected genetic advance of 39.5% is considered to be more useful in predicting the outcome of selecting the best individuals. Chi-square values were computed to determine whether the observed ratios for disease reactions deviated from expected Mendelian ratios for a single, dominant gene controlling resistance to angular leaf spot in common bean. Based on the resistance of the F2, and the backcross generation to the resistant parent, a 3 resistant: 1 susceptible segregation ratio in the F2 and a 1 resistant: 1 susceptible segregation ratio in the backcross generation to the susceptible parent was obtained implying that resistance to the isolate of Phaeoisariopsis griseola is governed by a single, dominant gene.
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    Genetic characterization of angular leaf spot resistance in selected common bean landraces from Tanzania
    (African Journal of Biotechnology, 2015-10-28) Tryphone, George Muhamba; Chilagane, Luseko Amos; Nchimbi-Msolla, Susan; Kusolwa, Paul Mbogo
    Angular leaf spot disease (ALS) caused by Pseudocercospora griseola is one of the most important bean diseases in Tanzania. The bean landraces Beti-10, Nanka, Nanavala and Nkanamna used in this study have been identified as resistant to ALS but the nature of inheritance and mechanisms of resistance against ALS in those potential sources has not been elucidated. This information is crucial and a necessary first step for a successful breeding programme. The objective of this work was to study the inheritance of ALS resistance in those landraces and to identify the mechanisms of genetic resistance using Simple Sequence Repeat (SSR) markers. Crosses were made between resistant bean landraces and a susceptible bean cv Kablanketi. The parents, F1, F2 and backcrosses derived plants were used for inheritance studies and for molecular marker screening using 30 SSR markers. Results indicate that, a single dominant gene control resistance against ALS in each of the four landraces; also the SSR marker Pv-ag004 was found to be polymorphic between Beti-10 and Kablanketi and linked to the disease resistance. The resistance were validated by checking the F2 population of the cross between Kablanketi × Beti-10. Therefore, since marker Pv-ag004 is polymorphic and linked to ALS resistance, the Beti-10 landrace might be a potential source of ALS resistance. However, a detailed study with more markers need to be done on these landraces with a view to opening the possibilities of identifying new markers linked to ALS resistance and mapping of genes associated with resistance to ALS.
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    Incorporation of resistance to angular leaf spot and bean common mosaic necrosis virus diseases into adapted common bean (Phaseolus vulgaris L.) genotype in Tanzania
    (African Journal of Biotechnology, 2012-07-03) Chilagane,Luseko Amos; Tryphone,George Muhamba; Protas, Deogracious; Kweka, Elisiana; Kusolwa, Paul Mbogo; Nchimbi-Msolla, Susan
    Angular leaf spot (ALS) caused by the fungus Pseudocercospora griseola and Bean common mosaic and necrosis virus (BCMV/BCMNV) are important diseases of common bean in Tanzania that can cause severe yield reduction when uncontrolled. This study was conducted to incorporate resistant genes for ALS and BCMV/BCMNV diseases into adapted, market class and farmers and consumers preferred bean genotype using marker assisted selection. The parents Mexico 54 and UBR(25)95 donor of Phg-2 and I/bc-3 genes for ALS and BCMV/BCMNV, respectively were used for the recipient being Kablanketi. In selection, SCAR markers SNO2, ROC11 and SW13 linked to Phg-2, bc-3 and I gene, respectively were used. A parallel backcrossing (modified double cross) procedure was used. The F1, F2 and backcrosses from single crosses were characterized. The Chi square values for ALS were 0.081 (P<0.776) and 0.017 (P<0.896) and for BCMNV were 1.609 (P<0.205) and 1.2 (P<0.273) for molecular and phenotypic screening, respectively. The resistance to ALS and BCMNV was found to be monogenic and the genes involved are dominant and recessive, respectively. The heritability of ALS was found to be high (0.772) implying that selection for ALS can be done early in segregating populations. High correlation values, r = 0.741 and 0.624 for ALS and BCMNV, were obtained between phenotypic and molecular data, indicating high reliability for markers. In selection, it was possible to select lines with multiple disease resistances. This work signified the use of MAS for multiple gene screening.
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    Common weeds found in selected cassava farms in Eastern zone of Tanzania
    (Greener Journal of Agricultural Sciences, 2022-04-04) Leonard, Joseph A.; Kudra, Abdul B.; Baijukya, Frederick; Tryphone, George M.
    A field study was conducted at Kiimbwanindi village, Mkuranga district and Ilonga village, Kilosa district. Coast and Morogoro regions of Tanzania, respectively to identify the common weeds affecting cassava fields. A total of 24 random 1 m × 1 m quadrat were placed in each cassava field where by all weed species found in each quadrat were identified to a species level. During weed identification, weed density, uniformity and frequency were calculated according to Thomas methodology and used to determine weeds’ relative abundance. Also, a composite soil samples were collected based on random sampling procedure at a depth of 0 to 50 cm from each field before land preparation and analysed in the laboratory in order to determine the amount of nutrient content available in the soil. A total of 22 weeds species belonging to 16 families were identified, whereby out of these 14 were broad leaved weeds, 6 grassy weeds, 1 mushroom and 1 sedged weed belonging to 10 perennial and 12 annual weeds plant. During weed identification, Cyperus rotundus and Echinochloa colona were the most abundantweed species while Dactyloctenium aegyptium, Portulaca oleracea, Agaricus sp and Bidens pilosa were the least occurred weed species. Perennial weeds Cyperus rotundus, Echinochloa colona, Trichodesma zeylanicum, Reissantia sp, Mucuna pruriens and Commelina benghalensis found to be the mostly abundant weed species due to their ability to adapt into various soil types and their ability to reproduce as compared to other weeds. The study recommended that, research toward new or improved weed control measures is needed and also more survey work is needed on a regular basis to identify possible weed population shifts.
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    Variability of common bean (Phaseolus vulgaris L.) in Tanzania as evidenced by morphological assessment
    (Greener Journal of Agricultural Sciences, 2022) Yanda, Focus Edson; Tryphone, George Muhamba
    A total of 84 common bean (Phaseolus vulgaris L.) accessions were collected from different areas of Tanzania serving as source of germplasm. Nineteen agromorphological traits of 84 common bean accessions were assessed to analyze the variability as a core objective for this study. Among all the accessions, 40.48% were characterized by indeterminate bush with moderate climbing ability and pods distributed evenly up to the plant habitus followed by 36.9%. Similarly, 14.29% were the genotypes with indeterminate bush with semi-climbing main stem and branches habitus genotypes. Also, 14.29% were the genotypes with the indeterminate bush with prostrate, and 7.14% were the genotypes with indeterminate bush with erect branches habitus while 1.19% were the genotypes with determinate bush least. Phonological, quantitative and qualitative traits were evaluated and their scores were subjected to principal component analysis and cluster analysis. The phylogenetic tree demonstrated 2 major clusters which were further divided into sub-clusters. Principal component analysis accounted for the accumulative variance of 35.78% revealing morphological variation highly attributed with variables which had greater than 0.2 Eigen values. The study demonstrated low morphological variation among the genotypes and emphasized the need to broaden genetic variability of the common bean in Tanzania. The results of this study can be used to select the valuable breeding material for use. Besides, molecular markers can be deployed to assess further the variability and diversity of these genotypes.
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    Indirect selection for resistance to Alectra vogelii (benth) infestation in cowpea (Vigna unguiculata)
    (International Journal of Environment, Agriculture and Biotechnology (IJEAB), 2017) Mbwando, A.; Lungu, D. M.; Tryphone, G. M.; Tembo, L.
    Alectra vogelii (benth) is a parasitic weed which causes significant yield reductions in cowpeas (Vigna unguiculata Walp) in most of the sub-Saharan African countries. The objective of this study was to establish the effect of Alectra vogelii infestation on yield components of cowpea and the prospects of utilizing these components for indirect select to A. vogelii in resistance breeding. Seven genotypes of cowpea were crossed in all possible combinations without reciprocals and their 21 F2 progeny including parents were evaluated for reaction to Alectra vogelii infection at two locations, Ilonga and Hombolo. The experiments were laid using a Randomized Complete Block Design with three replications. Significant (P < 0.001) genotypic responses to Alectra emergency and infestation were found. A significance negative correlation was found between the Alectra emergency and infestation to yield and yield components (P< 0.01 and P< 0.001). However, both yield components (Number of pods per plant and 100 seed weight) tested exhibited a weak r2 value (< 0.25) implying that these components can only be used to supplement and not as a substitute to direct selection in breeding for resistance to A. vogelii.
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    Unexplored agronomic, socioeconomic and policy domains for sustainable cotton production on small landholdings: a systematic review
    (2023-11-20) Tlatlaa, Jacob Shauri; Tryphone, George Muhamba; Nassary, Eliakira Kisetu
    Cotton productivity continues to be disputed, despite rapid advancements and widespread technologies. These uncertainties remain to be critically addressed in a broad spectrum focusing on domains at the global level. Therefore, this systematic review provides an overview of the existing advancements in knowledge, skills, and technologies for sustainable cotton production on small landholdings. Specifically, the areas of the cotton chain examined are threefold: - (1) Explore disguised agronomic practices to be endowed for sustainable cotton production on small landholdings; (2) Explore socioeconomic settings based on their disparities in contributing to sustainable cotton production on small landholdings; and (3) Explore existing and feasible institutional policies to be enforced for sustainable cotton production on small landholdings. This review shows that worldwide cotton production involves conventional and organic systems, at the expense of the traditional system. Heavy uses of nitrogenous fertilizers and pesticides are the common practices in conventional systems, with some adoptions of precision agriculture practices, and genetically modified varieties. Rotation and intercropping with early-maturing food crops are also identified viable options to improve farmers’ attitudes toward adopting cotton- producing technologies. In socioeconomics, farmers’ livelihoods are improved by income generation from sales of cotton and labour in the cotton industry. Gender equity in the cotton industry prioritizes females over males, as females display a group with a higher level of technology adoption. Generally, clear institutional policies governing the cotton industry are globally paucity. Furthermore, efforts to sensitize sustainable cotton production are still highly questionable and challenged by the superseding climate changes.
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    Elucidating the effect of genotype x environment interaction and storage period on cooking time of selected common bean (Phaseolus vulgaris L.) genotypes
    (East African Journal of Science, Technology and Innovation, 2023-09-14) Mvile, A. J.; Nchimbi, Msolla S.; Tryphone, G. M.
    The cooking time of Common beans (Phaseolus vulgaris L.) is among the important consumer’s preferred traits. Slow-cooking beans lose some important micronutrients (Fe and Zn) because prolonged cooking degrades the beans at a cellular level. Fast-cooking beans save fuel energy and time which could have been spent on slow-cooking beans. Storage conditions, seed composition, cooking method, and growing environment also have an effect on the cooking time of common beans. Thirty bean genotypes with checks (Rojo and SUA-90) were laid in a Randomized Complete Block design in three environments (Ndole, Kasanga, and Mlali) in the Morogoro region. After harvesting cooking time determination was held using an automated Mattson Cooker soon after harvesting and repeated after three months (90 days). Analysis of variance revealed a significant variation (P < 0.001) among genotypes and across the environments for the first and second cooking tests. In a combined analysis, cooking time unveiled a continuous distribution ranging from 72.3-121.2 minutes for the first cooking test and 104.8-215.1 minutes for the second cooking test. Selian 10 and KT-002 recorded the shortest cooking time in the first and second cooking tests while TARI-06 and NUA-746 recorded the longest cooking time. The GGE biplot revealed SUA-90, Selian 10, NUA-672, and KT-002 were the most stable and fast-cooking genotypes in the first cooking test while NUA- 746, TARI-06, and ADP-190 maintained stability but took a long time to cook. In the second cooking test, Selian 10, Uyole-04, and Selian 97 revealed high stability with a short cooking time while TARI-06 and NUA-746 revealed high stability with a long cooking time. These findings suggest that some bean genotypes can maintain the stability of fast cooking traits even after being stored for a certain time, hence these candidates can be used for breeding purposes or released as varieties.
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    Effects of sowing dates and phosphorus levels on cotton growth and yield: soil analysis and implications
    (Frontiers in Sustainable Food Systems, 2023-09-20) Tlatlaa, Jacob Shauri; Tryphone, George Muhamba; Nassary, Eliakira Kisetu
    This study assessed the effects of sowing dates and phosphorus levels on cotton performance in Chato-Msilale village in Chato District, Tanzania. The soil analysis revealed that field exhibited slightly acidic soil with normal electrical conductivity but suffered from severe deficiencies in total nitrogen and organic carbon. The same field presents common issue of low cation exchange capacity, indicating limited nutrient-holding capacity. Furthermore, both fields displayed very low levels of total nitrogen (<0.1%), signaling a nitrogen deficiency. Available phosphorus was rated as medium (16.8 mg kg −1 soil). Trace elements fluctuated and could be managed based on specific crop requirements. The factors at different levels were: (1) sowing dates – (i) 25th November 2022, (ii) 15th December 2022, and (iii) 4th January 2023; and (2) Phosphorus levels – (i) control, (ii) 20 kg P ha −1 , (iii) 40 kg P ha −1 , and (iv) 60 kg P ha −1 . Regarding cotton growth and yield, sowing dates significantly (p < 0.001) influenced plant height, gin turnout, lint yield, number of bolls per plant, and boll weight while phosphorus levels did not exhibit significant effects. Earlier sowing dates resulted in higher yields, albeit with variations in yield components. Interactions showed that growth and yields were only numerically higher in the middle sowing date at higher levels of phosphorus applied. Overall, these insights offer valuable guidance for optimizing cotton cultivation in Chato District, emphasizing the importance of selecting appropriate sowing dates for improved yields.
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    Impact of cucurbit crop management techniques on the foraging behavior of honeybees and hoverflies in Morogoro, Tanzania
    (BMC Ecology and Evolution, 2024) Rweyemamu, Elvillah William; Mwatawala, Maulid Walad; Tryphone, George Muhamba; Meyer, Marc De; Kabota, Sija; Bwire, Patroba Masatu
    Background Poor agricultural practices have drastically threatened insect pollinators’ biodiversity. Little is known in Tanzania about how different agricultural practices affect pollinators’ foraging behavior. This study investigated the effects of the agroecological zone, season, cucurbit species and management practices on visitation frequency, visitation rate and time spent on cucurbit flowers by five pollinator species viz. Apis mellifera, Eristalinus megacepha- lus, Mesembrius caffer, Paragus borbonicus and Toxomerus floralis. The experiment was designed as a 5 × 3 × 3 × 2 × 2 factorial arrangement in a Randomized Complete Block Design (RCBD) with four replications. GAMOUR-Agroecology was tested against conventional practices and untreated control. Results This study revealed significant effects of agroecological zone × season × cucurbit species × management practice on pollinators’ visitation frequency (p = 0.007) and time spent on flowers (p = 0.005). Also, agroecological zone × season × cucurbit species × pollinator species significantly (p < 0.0001) affected pollinators’ visitation frequency. Agroecological zones × season × cucurbit species × cucurbits management practices × pollinators significantly (p = 0.001) affected pollinators’ visitation rate. Apis mellifera was the most frequent visitor in Cucurbita moschata plots treated with GAMOUR- Agroecology in the plateau zone, also, visited higher number of Cucumis sativus plots under GAMOUR-Agroecology practices in the mountainous zone during the October–November season. Further- more, it has been found that pollinators spent much in cucurbit flowers on plots with GAMOUR-Agroecology prac- tices and control. Conclusions Pollinators’ foraging behavior were enhanced by GAMOUR-Agroecology practices. Therefore, this study recommended that cucurbit growers should consider management practices that positively influence pollinator foraging activities for sustainable cucurbit production
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    Facilitating international agricultural trade through science: the case of tephritid flies
    (Sokoine University of Agriculture, 2018-03-20) Prof. Maulid Walad Mwatawala
    International agricultural trade is important in addressing spatial and temporal food shortages across the globe. Agricultural trade generates income and contributes to economies of many countries. Unfortunately, there are various risks associated with the movement of agricultural commodities across borders. The spread of pests across countries is one of the great risks. The International Plant Protection Convention (IPPC), which is an agreement between nations, aims at preventing and controlling the introduction and spread of pests of plants and plant products across national boundaries. IPPC formulates various standards and guidelines that can be adopted by member states to formulate municipal phytosanitary laws against the introduction of pests. Countries normally conduct Pest Risk Analysis (PRA) in order to facilitate agricultural trade. This process requires scientific evidence on the identity and occurrences of pests in an area and a possible entry and the establishment and the spread of those pests into exotic places. Fruits and vegetable trade is important for food and security among the global population. However, fruit trade introduces the risk of the spread of pests, including fruit flies. Most fruit flies cause heavy losses to the fruit industry and these are therefore of quarantine importance. Research which has been conducted across the globe provided scientific evidence on the possible spread of fruit flies in order to facilitate trade. The Sokoine University of Agriculture (SUA) collaborated with various partners in the world to generate important information that is a prerequisite for conducting PRA. This inaugural lecture highlights key findings that include identification of new species, resolution of cryptic species, host range and preference, spatial and temporal distribution, and mitigation options against the selected economically important fruit flies.
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    Awareness and application of existing agroecological practices by small holder farmers in Mvomero and Masasi districts-Tanzania
    (Canadian Center of Science and Education, 2020-12-15) Constantine, John; Sibuga, Kallunde P.; Shitindi, Mawazo J.; Hilberk, Angelika
    A survey study was conducted to assess the level of awareness and application of existing agro-ecological practices by small holder farmers in Mvomero and Masasi districts in Tanzania. The selection of farmers to interview and the villages in the respective districts was based on their long history of producing cassava and maize. A structured questionnaire was used to identify the type of agro-ecological practices, agricultural information sources accessed by farmers, training on agro-ecological practices, type of crops grown in the study areas and kind of livestock kept. Results indicated that the most applied agro-ecological practices were diversification (80.5%), the use of farmer saved seeds (78.2%) followed by intercropping (72.9%) and lastly, agro-forestry (3.2%). The highest percentage of farmers (30.4%) reported to receive information on ecological organic agriculture from non-governmental organisations (NGOs) (SAT, SWISS AID), 27.5% were using own farming experience, 21% reported to receive the information from government extension officers, 13% from friends or neighbours, 4.3% from government institutions (SUA, Agricultural Training Institutes) and 3.6% received information from agricultural input suppliers. Generally, 50% of farmers had received training on agroecological practices indicating the level of awareness. Lack of knowledge among farmers was one of the key factors that hamper the wide application of agroecological practices. There was a need for farmer’s capacity building through training to enhance wider application of agroecological practices hence progressive agricultural production increase.
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    Controlling Tuta absoluta (Meyrick) by Selected Crude Plant Extracts in the Laboratory and in the Screen House
    (David Publishing, 2019) Matendo, Rehema Esther; Nonga, Hezron Emmanuel; George, Bakari; Nabintu Bintu, Ndusha; Mwatawala, Maulid Walad; Maerere, Amon Petro
    Effects of Commiphora swynnertonii, Synadenium glaucescens and Allium sativum extracts on the tomato leaf miner, Tuta absoluta (Meyrick) were evaluated on the adults and in screen house conditions. The adult stage was involved with 30 adults that were reared in an insectarium, the experimental design was a completely randomized design (plant extracts from three plants species  three doses of 2%, 4% and 8%). In the screen house, experimental dispositive was a completely randomized block design (two varieties of tomatoes  three plants extracts). Larval counts were performed after 0, 1, 2, 3 and 7 d of treatment, 40 tomato leaves (10  4 replicates) were randomly taken from each treatment. The mean percentage mortality of adults was recorded daily for 5 d. Results indicated that, each plant extract caused significant mortality to adults of T. absoluta after 5 d in comparison to the control. Leaf dipping against adult of T. absoluta proved to be the most effective for all plant extracts at 30%-100%. Commiphora resulted in the adults’ mortality of 100%. In the screen house Commiphora showed the high reduction of infestation for Tanya and Cal J varieties. Treatment with this plant extract resulted in the highest fruit yield and the lowest yield loss compared to all the plant extracts. C. swynnertonii extract is recommended into integrated pest management strategies for the control of T. absoluta.
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    UAV-based multispectral vegetation indices for assessing the interactive effects of water and nitrogen in irrigated horticultural crops production under tropical sub-humid conditions: A case of African eggplant
    (Elsevier, 2022) Mwinuka, Paul Reuben; Mourice, Sixbert K; Mbungu, Winfred B; Mbilinyi, Boniphace P; Tumbo, Siza D; Schmitter, Petra
    UAV-based multispectral vegetation indices are often used to assess crop performance and water consumptive use. However, their ability to assess the interaction between water, especially deficit irrigation, and nitrogen application rates in irrigated agriculture has been less explored. Understanding the effect of water-nitrogen in teractions on vegetation indices could further support optimal water and N management. Therefore, this study used a split plot design with water being the main factor and N being the sub-factor. African eggplants were drip irrigated at 100% (I100), 80% (I80) or 60% (I60) of the crop water requirements and received 100% (F100), 75% (F75), 50% (F50) or 0% (F0) of the crop N requirements. Results showed that the transformed difference vegetation index (TDVI) was best in distinguishing differences in leaf moisture content (LMC) during the vegetative stage irrespective of the N treatment. The green normalized difference vegetation index (GNDVI) worked well to distinguish leaf N during vegetative and full vegetative stages. However, the detection of the interactive effect of water and N on crop performance required a combination of GNDVI, NDVI and OSAVI across both stages as each of these 3 VI showed an ability to detect some but not all treatments. The fact that a certain amount of irrigation water can optimize the efficiency of N uptake by the plant is an important criterion to consider in developing crop specific VI based decision trees for crop performance assessments and yield prediction.
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    Fungicidal effects of commiphora swynnertonii (burrt.) and synadenium Glaucescens (pax.) against tomato fusarium wilt disease
    (Elservier, 2023) Madege, Richard R; Babu, Saidi; Mabiki, Faith P; Mtui, Hosea; Kudra, Abdul
    Tomato fusarium wilt disease is an important soil-borne disease caused by Fusarium oxysporum f. sp. Lycopersici (FoL) worldwide. The disease causes yield losses of about 90% worldwide. This study aimed to evaluate the extracts of C. swynnertonii (resins) and S. glaucescens (latex, fresh and dry leaves) for their efficacy against FoL. In the laboratory, a 4 × 4 factorial experiment in a Complete Randomized Design (CRD) was carried out to evaluate resins, latex, fresh, and dry leaves each in four concentrations (0.01 g/ml, 0.05 g/ml, 0.1 g/ml and 0.15 g/ml). The negative and positive controls were Sterile Distilled Water (SDW) and a Linkmil 72 WP (Mancozeb 64% + Metalaxyl 8%) respectively. In a screenhouse, resins, latex, and fresh and dry leaves, each at 0.15 g/ml were applied on pre-inoculated tomato plants to manage TFW disease. The experiment was laid out in a Randomized Complete Block Design (RCBD) with four replications. The negative and positive controls were the untreated soil and soil treated with Linkmil 72 WP respectively. The differences between extracts in the in- hibition of radial mycelial growth of the pathogen were highly significant (p = 0.000). The efficacy of the plant extracts against in vitro growth of FoL was significantly dependent on the application dose. The inhibition of mycelial growth caused by latex and dry leaves was higher than that of Linkmil 72 WP (23.58%) and SDW (0%) by 41% and 65% respectively. Findings show that there was a TFW disease reduction of 72.92% 68.75% and 56.25% in plants treated with dry leaves, the latex of S. glaucescens, and resin of C. swynnertonii in that order. Plant extracts had significant effects (p = 0.000) on plant growth. The plants treated with dried leaf powder attained the highest height, the number of branches/plant, leaves/plant, and leaf area of 85.85 cm, 19.25,99.5 and 59.39 respectively. The findings benchmark the fungicidal potential of C. swynnertonii and S. glaucescens.
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    The feasibility of hand-held thermal and UAV-based multispectral imaging for canopy water status assessment and yield prediction of irrigated African eggplant (Solanum aethopicum L)
    (Elsevier, 2021) Mwinuka, Paul Reuben; Mbilinyi, Boniface P; Mbungu, Winfred B; Mourice, Sixbert K; Mahoo, H.F; Schmitter, Petra
    This study was conducted to evaluate the feasibility of a mobile phone-based thermal and UAV-based multi spectral imaging to assess the irrigation performance of African eggplant. The study used a randomized block design (RBD) with sub-plots being irrigated at 100% (I100), 80% (I80) and 60% (I60) of the calculated crop water requirements using drip. The leaf moisture content was monitored at different soil moisture conditions at early, vegetative and full vegetative stages. The results showed that, the crop water stress index (CWSI) derived from the mobile phone-based thermal images is sensitive to leaf moisture content (LMC) in I80 and I60 at all vegetative stages. The UAV-derived Normalized Difference Vegetation Index (NDVI) and Optimized Soil Adjusted Vegetation Index (OSAVI) correlated with LMC at the vegetative and full vegetative stages for all three irrigation treatments. In cases where eggplant is irrigated under normal conditions, the use of NDVI or OSAVI at full vegetative stages will be able to predict eggplant yields. In cases where, eggplant is grown under deficit irri gation, CWSI can be used at vegetative or full vegetative stages next to NDVI or OSAVI depending on available resources.
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    Identification of drought tolerant rice (Oryza Sativa L.) genotypes with Asian and African Backgrounds
    (MDPI, 2023) Ndikuryayo, Cyprien; Ndayiragije, Alexis; Kilasi, Newton Lwiyiso; Kusolwa, Paul
    Drought is among the major abiotic stresses on rice production that can cause yield losses of up to 100% under severe drought conditions. Neither of the rice varieties currently grown in Burundi can withstand very low and irregular precipitation. This study identified genotypes that have putative quantitative trait loci (QTLs) associated with drought tolerance and determined their performance in the field. Two hundred and fifteen genotypes were grown in the field under both drought and irrigated conditions. Genomic deoxyribonucleic acid (DNA) was extracted from rice leaves for further genotypic screening. The results revealed the presence of the QTLs qDTY12.1, qDTY3.1, qDTY2-2_1, and qDTY1.1 in 90%, 85%, 53%, and 22% of the evaluated genotypes, respectively. The results of the phenotypic evaluation showed a significant yield reduction due to drought stress. Yield components and other agronomic traits were also negatively affected by drought. Genotypes having high yield best linear unbiased predictions (BLUPs) with two or more major QTLs for drought tolerance, including IR 108044-B-B-B-3-B-B, IR 92522-45-3-1-4, and BRRI DHAN 55 are of great interest for breeding programs to improve the drought tolerance of lines or varieties with other preferred traits.