Agro-ecological Zones Of Tanzania Research Articles

Performance and Adaptability of Common Bean-Released Cultivars at Three Agro-Ecological Zones in Tanzania

This study focused on examining the genetic performance and stability of common bean genotypes across multiple environments in Tanzania using an alpha-lattice experimental design. The aim was to minimize environmental variability and maximize genetic expression. Three experimental sites were selected to represent the ecologies of the main bean growing areas of Tanzania, which are Tropical Savannah represented by TARI-Seliani, Tropical highlands represented by TARI-Uyole and semi-arid regions represented by Babati region. The sites were planted with are diverse of common bean genotypes, all of which were released for use in Tanzania. Agronomic practices, such as hand-hoe weeding and fertilizer application, were consistently applied. Key data collected included days to 50 percent flowering, growth habit, plant height, pod and seed count, yield per plot, and 100 seed weight. Advanced statistical analyses, including ANOVA, AMMI, and stability tests, were conducted using R software to evaluate yield and yield components. This paper findings discuss about the yield performance, stability, and the discriminating verses representative power across locations. In terms of yield, Babati was the leading site with mean yield of 1413.07 kilogram per hectare (kg/h)with Uyole 96 being the lead genotype (2845.567kg/h). Genotypes that were found to be stable and high-yielding in multiple locations include, Rojo, SUA Kalima, SAKILA, Fibea, and Nyeupe Uyole with the mean yields of 1045.83kg/h, 1023.73kg/h, 1003.33kg/h, 670.4kg/h and 544.77kg/h respectively. In discriminativeness and representativeness, Babati was the most discriminating site among the three locations while Seliani was the most representative among the three. These findings revealed significant variationsand allowed the assessment of genotype performance and environmental interactions.

Occurrence and associated risk factors of aflatoxin contamination in animal feeds and raw milk from three agroecological zones of Tanzania

Aflatoxins (AFs) are natural toxic compounds produced by a specific type of fungi, which subsequently contaminate foods and animal feeds, potentially carcinogenic to humans. This study assessed the AFs awareness, prevalence and associated risk factors through a survey of the smallholder dairy farmers (SDFs) and livestock feeds and raw cow milk samples from three agroecological zones in Tanzania. The aflatoxin awareness among SDFs (419) and agrovet dealers (26) was 23.2% and 50%, respectively. The prevalence of aflatoxin B1 (AFB1) in livestock feeds from agrovet dealers, and SDFs was 88.5 and 86.2%, with a concentration ranging from a limit of detection (LOD) to 22.99 and 32.9 μg/kg, respectively. However, 15.38 and 22.5% of AFB1 detected samples from agrovet dealers and SDFs exceeded the European Union (EU) and Tanzanian Bureau of Standards (TBS) limits of 5 μg/kg for dairy cow feeds. The prevalence of aflatoxin M1 (AFM1) in raw cow milk was 30.7%, of which 27.9% exceeded the EU and TBS limits of 0.05 μg/l for raw cow milk. The risk factors associated with AFB1 and AFM1 were cattle feeding systems: zero-grazing (odds ratio (OR) = 11.3 (1.5-22.9)) and mixed feeding (OR=16.0 (1.4-43.6)), use of concentrates feeds (OR=12.0 (0.6-55.6)), mixed feeding (OR=5.0 (0.5-11.1)); feed handling and storage practices: no moisture content measurement (OR=2.0 (0.3-15.0)) and storing feeds (OR=3.6 (1.7-8.5)); agroecological zones: central zone (OR=15.2 (5.4-50.6)) and northern zone (OR=2.1 (0.7-7.3)); aflatoxin (AF) awareness and level of education: primary (OR=16.0 (2.5-155.3)) and secondary education (OR=8.0 (2.14-43.9)) (P<0.05). This study revealed a high prevalence of aflatoxin contamination in animal feeds and raw cow milk, suggesting a potential health risk to consumers. Therefore, it is vital to increase awareness and knowledge on AFs, proper handling, storage and monitoring of feeds among the stakeholders in the dairy value chain.

Awareness and adaptations to climate change among the rural farmers in different agro-ecological zones of Tanzania

PurposeThis paper generally aimed to evaluate the knowledge of rural farmers towards climate change (CC) and their adaptation practices as a way of reducing the vulnerability in different agro-ecological zones (AEZs) of Tanzania. This establishment is quite important because rural farmers are most vulnerable to impacts of CC. Therefore, there is a need to establish the actual knowledge on this aspect in order to meet the urgency for action on CC by using the endowed environmental resources. This knowledge will assist policy makers and CC practitioners.Design/methodology/approachThis study employed systematic and simple random sampling procedures in selecting the districts and villages as study sites. It used both quantitative and qualitative data sets derived from climatic records, questionnaires survey, interviews and discussion. The Mann-Kendall test and Sen's slope, and theme content were used for data analyses.FindingsThe results exhibited that most farmers have been greatly adapting to CC through numerous and well-known practices. However, there has been adoption of other new practices mainly influenced by new knowledge from extension services, environmental endowments and temporal environmental change. Although there has been varied perceptions on CC, the results indicate that most farmers (>70%) are aware of the changing climate and their knowledge corresponds to meteorological data.Originality/valueMost farmers perceived that prolonged drought and erratic rains are the main indicators of CC. These indicators were the base of copping and adaptation mechanisms. Despite this, there is a need for all climate practitioners to join hands in improving the existing adaptation practices that can limit climate impacts in local areas.

Typology and characteristics of indigenous goats and production systems in different agro-ecological zones of Tanzania

Tanzania has a goat population of about 24.8 million most of which belong to the Small East African breed distributed in almost all agro-ecological zones. The different goat populations and the production system in which they are raised are not well characterized depriving animal breeders useful information in designing and running improvement and conservation programs. Therefore, the study was conducted in all agro-ecological zones in Tanzania to characterize the indigenous goats and the production system in which they are raised. Data on animals were collected from 688 randomly selected adult female goats and for production system description; 220 households were interviewed. Analysis of variance and discriminant analysis were used on quantitative data, while frequency analysis was used on qualitative data. Income generation and meat production were the primary goat rearing objectives. More than 55% of respondents grazed their animals freely in communal lands where natural pasture was the chief feed resource. Mating was mainly uncontrolled with apron and castration being used by goat keepers as mating control methods. Common diseases were contagious caprine pleural pneumonia and helminthiasis. Feed shortage, prevalence of diseases, and water scarcity were the major goat production constraints. There were morphological variations between and within these goat populations, and based on quantitative data, the goats were categorized into two groups. High twinning was observed in Ujiji and Lindi goats and low for Sukuma. The dominant coat color was plain white in Pare, Gogo, Maasai, and Tanga. Other coat color patterns were mixed black and white for Sukuma, reddish-brown for Lindi, black and reddish-brown for Ujiji, and white and reddish-brown for Pwani and Maasai. High within population variation is observed which is important as it can be used as a basis for genetic improvement through selection.

Diversity in fruit and seed morphology of wooden banana (Entandrophragma bussei Harms ex Engl.) populations in Tanzania

Entandrophragma bussei (wooden banana) is a high value indigenous multipurpose tree species prioritized for domestication in Tanzania. However, we lack adequate information on genetic and phenotypic variation to support domestication processes, while utilization pressure on the remaining stocks and deforestation are intensified. The study evaluated the diversity in fruit and seed morphology of three wild populations of E. bussei found in three agroecological zones of Tanzania. Data on fruit (length, width, weight and number of seeds per fruit) and seed (length, width and weight) traits were evaluated. To detect differences in means among the populations, one-way Analysis of Variance (ANOVA) was performed. There were variations in fruit and seed morphological traits among the studied populations. Ruaha population had significantly higher fruit length (19.31 ± 0.1 cm), width (7.71 ± 0.12 cm) and number of seeds per fruit (22 ± 0.48) than Kigwe (15.65 ± 0.14 cm, 4.85 ± 0.17 cm, 20 ± 0.45), and Tarangire (16.84 ± 0.1 cm, 5.40 ± 0.12 cm, 20 ± 0.37) populations. Ruaha (62.46 ± 1.37 g) and Tarangire (60.71 ± 1.12 g) had significantly heavier fruits than Kigwe (56.53 ± 1.28 g). Kigwe population had significantly higher seed width (1.80 ± 0.01 cm) and weight (0.83 ± 0.01 g) than Ruaha (1.75 ± 0.01 cm, 0.75 ± 0.01 g) and Tarangire (1.65 ± 0.01 cm, 0.77 ± 0.01 g) populations. Among the populations Tarangire had higher seed length (9.60 ± 0.06 cm) than the rest. Overall, there is a considerable fruit and seed morphological diversity among the E. bussei populations offering opportunities for selection of domestication cultivars and gene pool conservation.

Euphorbia tirucalli stem bark and phylloclades’ oil quality variability and implication for energy use

Liquid biofuels have emerged as a worldwide alternative fuel with potential to replace fossil fuels. Due to their wide availability as derivatives of organic materials from plants, they have attracted much attention and investment in developing countries including Tanzania, as alternative sources of energy. This study examined effects of oil quality from stem barks and phylloclades of Euphorbia tirucalli trees of different girth sizes (viz., 20 cm, 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, and 80 cm) from semi-arid, coastal, and southern highlands in Dodoma, Dar es Salaam, and Mbeya Southern highland, agro-ecological zones in Tanzania. Using Soxhlet extraction method, oils were extracted from E. tirucalli stem barks with different girth sizes while oils from phylloclades were extracted from matured apical phylloclades collected from shoots of E. tirucalli trees from which the stem bark samples had been collected. Oil yields were determined by measuring the weight of oil (g) by the total weight of sample extracts used (20 g), and the average oil yield on each sample was determined. Oil quality was evaluated as oxidative stability index (OSI), acid values (AVs), and percent free fatty acids (%FFAs). Their results were then compared with the European Union (EU) oil quality standard specifications prescribed in EN 14214 of 6 h, 0.5 mg KOH/g, max and 0.020 maximum wt% limits, respectively. Differences in the quality of E. tirucalli (stem bark and phylloclades) oil were analyzed statistically with paired-sample t test (two-tailed) using the SPSS 15.0 software package. Results showed that the difference in OSIs from stem barks were not significantly higher (3–5 h) than phylloclades (3–4 h) at the p > 0.5 level. Also, the difference in AVs and %FFAs from the stem barks (7.6–7.4 mg KOH and 3.8–3.6%) was not significantly lower than those from the phylloclades (8.4–8.1 mg KOH and 4.3–4.0%) respectively. The quality of oil from stem bark and phylloclades samples at different stem girth sizes semi-arid agro-ecological zone was not significantly higher than from southern highland and coastal agro-ecological zones, respectively. Thus, there were no significant differences in the quality of E. tirucalli oil (stem bark and phylloclades) among stem girth sizes in different agro-ecological zones. The AVs and %FFAs of oils from stem bark and phylloclades were higher than the recommended standards, while the OSIs were below the biofuel standard limit. High AVs and %FFAs reduced oil quality by producing considerably low OSIs values than recommended standards. Finally, the study concluded that E. tirucalli oil requires purification to reduce levels of AV and %FFA contents so that the oil becomes suitable for application as liquid biofuel for energy generations.

Environmentally stable common bean genotypes for production in different agro-ecological zones of Tanzania

Genotype by environment interaction (GxE) complicates the process of selecting genotypes suitable for quantitative traits like seed yield in beans, hence slows down the development and release of varieties by breeding programs. GxE study on seed yield in beans enables identification of stable genotypes across sites and best site(s) for discriminating the tested genotypes in terms of seed yield. The purpose of this study was to evaluate the influence of the environment, genotype, and genotype by environment interaction on seed yield stability and adaptability of common bean landraces, lines, and improved varieties across three different agro-ecologies in Tanzania. The 99 common bean genotypes (Landraces, lines, and improved varieties) were planted following alpha lattice design in three replications each contained five blocks with 20 plots. Soil properties from the experimental sites, days to 75% flowering, Seed yield, 100 seed weight, number of seeds/pod, and number of pods/plant were recorded. Data on seed yield and its components were analyzed using Additive main effect and multiplicative interaction (AMMI), genotype main effects plus genotype × environment interaction (GGE), and yield stability index (YSI). The AMMI revealed very highly significant (P ≤ 0.001) effects of genotypes, environmental, and genotype × environment interaction on all the traits. AMMI analysis revealed that genotype main effects accounted for 39.3% of the total sum square of seed yield, whereas the environment and genotype × environmental interaction accounted for 31.4% and 26.8 % respectively. Genotype main effects largely influenced the variation in days to 75% flowering (55.5%), number of pods/plant (49.2%), number of seeds/pod (73.3%), and 100 seed weight (71.2%). Among soil properties recorded, available soil phosphorus, soil pH, soil exchangeable K, Ca, and Na had a strong positive association with common bean seed yield, while soil organic carbon and total nitrogen exhibited a strong negative association with seed yield. GGE revealed that E1 (TARI-Selian) was the most discriminative and representative site for common bean genotypes seed yield. Based on the yield stability index, the most stable and high seed yielding genotypes were ACC 714, Selian 14, Selian 9, Katuku, and Msolini. The identified high seed yielding and stable genotypes can be further tested in participatory variety selection involving farmers and later on released as varieties and can also be used for different breeding purposes in different agro-ecologies of Tanzania.

Pathological and biochemical descriptors of Ralstonia solanacearum of tomato (Solanum lycopersicum) in Tanzania

An experiment was conducted to identify bacterial wilt disease-causing isolates of Ralstonia solanacearum (Smith) in Tanzania. The pathological and biochemical descriptors were used to determine the virulence and biovars of 40 bacterial isolates originating from 200 wilted tomato (Solanum lycopersicum L.) stems collected from the main agro ecological zones of Tanzania. Results revealed that 53% of the investigated isolates were pathogenic, whereas 90% of isolates belonged to biovar 3 and the rest (10%) were biovar 2. Biovar 3 was present in all of the surveyed agroecological zones, whereas biovar2 prevailed in Southern zone only and is reported for the first time in Tanzania. This is an alert for plant health officers to implement standard phytosanitary measures in preventing new introduction and spread of Ralstonia to uninfected locations. Descriptors adopted successfully identified biovars of Ralstonia, thus can be integrated with other diagnosis tools to manage bacterial wilt disease.

English

Breeding for resistant varieties has been shown to be the most suitable method to control bean anthracnose caused by Colletotrichum lindemuthianum though the method is challenged by the existence of many races of the pathogen. This work focused on characterizing races of C. lindemuthianum from potential bean agro ecological zones of Tanzania using a set of differential bean cultivars. From 144 anthracnose infected bean samples collected, 50 pure isolates were obtained and characterized whereby 42 races were identified. The most virulent race identified was race 3610 from the Southern Highland zone of Tanzania while the least virulent was characterized as race 0. Race 2 was the most widely spread (4.2 %) found in Northern, Southern highland and in Eastern zones of Tanzania. The work confirms that G2333 can still be used as a potential donor of resistant genes to varieties that are to be grown in Northern, Eastern and Lake zones but not for the varieties from Southern Highland and Western zones of Tanzania since isolates from these zones overcame resistant genes Co-42, Co-5, Co-7 in G2333. 95% of all races which were identified are new and were not specific to either Mesoamerican or Andean origin common bean.   Key words: Colletotrichum lindemuthianum, races, resistant genes, differential cultivars, Anthracnose.

Detection of Contagious Caprine Pleuropneumonia and Concurrent Diseases in Outbreaks Presenting with Respiratory Signs in Small Ruminants in Tanzania

Aims: To establish the prevalence and concurrent diseases in outbreaks presenting with respiratory signs, major associated clinical signs and postmortem lesions and proportions of those diseases in clinically and autopsied small ruminants for a proper diagnosis and control strategies.
 Study Design: Purposive outbreaks investigation.
 Place and Duration of Study: Department of Global Health, School of Life Science and Bio-Engineering (LiSBE), Nelson Mandela Institution of Science and Technology (NM-AIST) between September 2016 and December 2018.
 Methodology: We included investigations of outbreaks of diseases presenting with respiratory signs in small ruminants reported from five agro-ecological zones in Tanzania. Small ruminats with clinical signs or postmortem lesions suggestive of respiratory involvement were subjected to clinical or postmortem examination. Samples from all examined animals were tested in the laboratory using conventional polymerase chain reaction (PCR) to confirm the tentative diagnosis.
 Results: A total of 205 small ruminats were examined and tested, of these 72.2% and 20.8% were goats and sheep respectively. In goats, 79.1% (117/148) and sheep, 28.1% (16/57) were confirmed to have concurrent infections, and pneumonic pasteurellosis and peste des petits ruminants (PPR) for goats, and PPR for sheep being mostly involved diseases. Contagious caprine pleuropneumonia (CCPP) was detected in 16.1% (n=205) of the animals, and was significantly high in goats (p=0.003, OR=7.3) than sheep. Pneumonic mannheimiosis (prevalence = 9.3%) was less likely to affect goats than sheep (p=0.047, OR=0.38). In goats (n=148), detection of all diseases was significantly (p<0.05) low in clinically examined animals except pneumonic pasteurellosis and PPR, (p =0.056, OR=2.1) and (p=0.096, OR=2.15) respectively, though the difference was not significant. In sheep (n=57), CCPP was significantly (p=0.005, OR=0.17) more likely to be detected in clinically examined animals.
 Conclusion: In investigations of outbreaks presenting with respiratory signs in small ruminants, it is important to consider concurrent infections in the interventions and control strategies to be deployed, which may include development and use of multivalent vaccines.

A Comparative study of the Sero-prevalence of Peste Des Petits Ruminants Virus among Districts of Different Agro-Ecological Zones in Tanzania

Peste des petits Ruminants (PPR), a disease affecting sheep and goats, was confirmed in Tanzania in the year 2018. Since then the disease has continued to spread into different districts, causing significant socio-economic losses to livestock keepers. This study aimed at determining the sero-prevalence of PPR in 32 districts from the coastal, semi-arid and plateau ecological zones, respectively. Sera samples were collected from sheep and goats, and analysed by competitive Enzyme Linked Immunosorbent Assay (c-ELISA). Findings indicated that six (18.8%) districts had very high PPR sero-prevalence of which four (66.7%; Chamwino, Kondoa, Mvomero and Kilosa) belong to the semi-arid ecological zone and two (33.3%; Bagamoyo and Mkuranga) to the coastal ecological zone. Three districts (9.4%) had high PPR sero-prevalence, all from the semi-arid ecological zone. Twelve districts had low PPR sero-prevalence of which two (16.7%) were from semi-arid, one (8.3%) from coastal and nine (75.0%) from plateau ecological zones. A zero PPR sero-prevalence was recorded in three districts and eight districts from semi-arid and plateau ecological zones, respectively. There was a statistically significant difference in sero-positivity between the different ecological zones, ?2 (2) = 9.121, p = 0.010, with a mean rank sero-positivity of 24.7% for coastal zone, 12.0% for plateau and 20.8% for semi-arid zone. Post hoc pairwise comparison with Bonferroni correction for multiple tests showed a statistically significant difference between plateau and semi-arid zones (p = 0.032). Although the coastal zone had a higher mean rank positivity than the plateau zone, the difference was not statistically significant (p = 0.083). The study suggests a zonal predisposition of PPR sero-prevalence with districts in the semi-arid and coastal zones having significantly higher values compared to those in the plateau ecological zones. Efforts for control of the disease need to concentrate in those two high risk ecological zones.

Agro-Morphological Exploration of Some Unexplored Wild Vigna Legumes for Domestication

The domestication of novel or hitherto wild food crops is quickly becoming one of the most popular approaches in tackling the challenges associated with sustainable food crop production, especially in this era, where producing more food with fewer resources is the need of the hour. The crop breeding community is not yet completely unanimous regarding the importance of crop neo-domestication. However, exploring the unexplored, refining unrefined traits, cultivating the uncultivated, and popularizing the unpopular remain the most adequate steps proposed by most researchers to achieve the domestication of the undomesticated for food and nutrition security. Therefore, in the same line of thought, this paper explores the agro-morphological characteristics of some wild Vigna legumes from an inquisitive perspective to contribute to their domestication. One hundred and sixty accessions of wild Vigna legumes, obtained from gene banks, were planted, following the augmented block design layout of two agro-ecological zones of Tanzania, during the 2018 and 2019 main cropping seasons for agro-morphological investigations. The generalized linear model procedure (GLM PROC), two-way analysis of variance (two-way ANOVA), agglomerative hierarchical clustering (AHC) and principal component analysis (PCA) were used to analyze the accession, block and block vs. accession effects, as well as the accession × site and accession × season interaction grouping variations among accessions. The results showed that the wild species (Vigna racemosa; Vigna ambacensis; Vigna reticulata; and Vigna vexillata) present a considerable variety of qualitative traits that singularly exist in the three studied checks (cowpea, rice bean, and a landrace of Vigna vexillata). Of the 15 examined quantitative traits, only the days to flowering, pods per plant, hundred seed weight and yield were affected by the growing environment (accession × site effect), while only the number of flowers per raceme and the pods per plant were affected by the cropping season (accession × season effect). All the quantitative traits showed significant differences among accessions for each site and each season. The same result was observed among the checks, except for the seed size trait. The study finally revealed three groups, in a cluster analysis and 59.61% of the best variations among the traits and accessions in PCA. Indications as to the candidate accessions favorable for domestication were also revealed. Such key preliminary information could be of the utmost importance for the domestication, breeding, and improvement of these species, since it also determines their future existence—that is, so long as biodiversity conservation continues to be a challenging concern for humanity.

Molecular approach to confirm traditional identification ofRadopholus similis sampled in Tanzania.

Banana (Musa spp. L.) is an important staple food and cash crop for about 30% of the population in Tanzania; however, the burrowing plant-parasitic nematode Radopholus similis causes black head disease and toppling in banana plants, which results in yield losses. We collected and identified 80 specimens of R. similis from four agro-ecological zones in Tanzania using morphological characters. We then used universal and specific R. similis primers to amplify the small subunit, internal transcribed spacer and large subunit of ribosomal DNA regions of these specimens. The amplicons were subsequently sequenced and analyzed using Bayesian inference. We identified two major clades, one that comprised all R. similis sequences derived from this study and another that included R. similis and Radopholus spp. sequences obtained from GenBank, indicating the separation of this species from congeneric sequences. Our findings provide a useful, simple and rapid method for identifying burrowing nematodes. This outcome could contribute to the development of permanent, integrated pest management strategies for the control of R. similis in banana and other crops in order to reduce associated yield losses in Tanzania. To our knowledge, this is the first study of nematodes to use combined morphological and molecular methods for the identification of R. similis in Tanzania.

Comparing Smallholder Farmers’ Perception of Climate Change with Meteorological Data: Experience from Seven Agroecological Zones of Tanzania

Abstract This paper examines and compares smallholder farmers’ perceptions of climate change with the collected meteorological data (1980–2015) across the seven agroecological zones (AEZs) of Tanzania. Systematic and simple random sampling procedures were employed in the selection of districts and villages, respectively. This study used both quantitative and qualitative datasets. Quantitative data were derived from climatic records and questionnaires, while the qualitative data were widely derived from interviews and discussions. The Mann–Kendall test (software) and theme content (method) were used for data analyses. The results showed that rain has experienced a significant change in terms of patterns, frequency, and intensity, while temperature was locally increasing in all the AEZs. Moreover, the farmers’ responses to both closed and open questions indicated that most of them (>70%) noticed these alterations. Comparatively, the farmers residing in the most vulnerable AEZs, that is, arid and semiarid lands, were more responsive and sensitive to climatic impacts than those in the least vulnerable zones, such as alluvial regions. The increase in temperature and change in the rain patterns led to the decrease in crop yields. As a response to this, farmers have adopted new strategies such as early planting and the use of shorter growing crops cultivars. This study concludes that, although farmers’ perceptions were correct and echoed the meteorological/measured data in all the AEZs, adaptation and mitigation strategies are inadequate.

Survey of Fungal Foliar and Panicle Diseases of Sorghum in Important Agroecological Zones of Tanzania and Uganda

A survey was conducted in 2014 to determine the prevalence of fungal diseases on sorghum across different agroecological zones in Tanzania and Uganda. In Tanzania, 37 sorghum fields were sampled in Dodoma and Singida Provinces, representing the central drier areas, and in Simiyu, Shinyanga, Mwanza, and Mara Provinces, representing the lake-zone region. In Uganda, 134 fields were sampled across four agroecological zones of Teso, Western, Northern, and West Nile. Farmers were purposively selected, and at least 30 plants per field along two diagonal transects were visually assessed for disease. Ten and 14 diseases were identified in Tanzania and Uganda, respectively. Among the major diseases identified, those more prevalent in Tanzania than in Uganda were leaf blight caused by Setosphaeria turcica (P = 0.0031) and rust caused by Puccinia purpurea (P < 0.0001). Major diseases more prevalent in Uganda than in Tanzania were anthracnose caused by Colletotrichum sublineola (P = 0.0207) and zonate leaf spot caused by Gloeocercospora sorghi (P = 0.0312). We report for the first time the occurrence of ladder leaf spot caused by Cercospora fusimaculans in Uganda and confirm its occurrence in Tanzania. This is the first comprehensive sorghum disease survey report in over 15 years in both countries.

Viruses infecting common bean (Phaseolus vulgaris L.) in Tanzania: A review on molecular characterization, detection and disease management options.

Common bean (Phaseolus vulgaris L.) is a major legume crop, serving as a main source of dietary protein and calories and generating income for many Tanzanians. It is produced in nearly all agro-ecological zones of Tanzania. However, the average yields are low (<1000 kg/ha), which is attributed to many factors including virus diseases. The most important viruses of common bean in Tanzania are Bean common mosaic virus (BCMV) and Bean common mosaic necrosis virus (BCMNV) but other viruses have also been reported. There has never been a review of common bean virus diseases in the country, and the lack of collated information makes their management difficult. Therefore, this review focuses on (1) occurrence of different viruses of common bean in Tanzania, (2) molecular characterization of these viruses, (3) detection tools for common bean viruses in Tanzania and (4) available options for managing virus diseases in the country. Literature and nucleotide sequence database searches revealed that common bean diseases are inadequately studied and that their causal viruses have not been adequately characterized at the molecular level in Tanzania. Increased awareness on common bean virus diseases in Tanzania is expected to result into informed development of strategies for management of the same and thus increased production, which in turn has implication on nutrition and income.

Risk of Exposure to Multiple Mycotoxins from Maize-Based Complementary Foods in Tanzania.

This study estimated exposure to multiple mycotoxins in 249 infants aged between 6 and 12 months in three agro-ecological zones of Tanzania. Maize-based complementary food intakes were estimated using two 24 h dietary recalls. Using @Risk software, probabilistic exposure assessment was conducted by modeling maize intake data (kg/kg body weight/day) with previously determined multiple mycotoxin (except for ochratoxin A (OTA) and zearalenone (ZEA), present in only a few samples) contamination data (μg/kg) in maize. Maize intakes ranged from 0.13 to 185 g/child/day (average = 59 ± 36 g/child/day). The estimated mean exposures were higher for aflatoxins (6-fold), fumonisins (3-fold), and deoxynivalenol (2-fold) than health-based guidance values of 0.017 ng/kg body weight/day, 2 μg/kg body weight/day, and 1 μg/kg body weight/day, respectively. The population at risk of exposures above the limits of health concern ranged from 12% for HT-2 toxin through 35% for deoxynivalenol to 100% for aflatoxins. The exposure varied among the agro-ecological zones. Strategies targeting multiple mycotoxins in maize are urgently needed to minimize exposures in Tanzania.

Climate change and variability impacts on agricultural production and livelihood systems in Western Tanzania

This article presents findings from a study conducted in Kasulu District in western Tanzania, to assess the impacts, vulnerability and adaptive capacity to climate change and variability of natural and social systems in various agro-ecological zones of Tanzania. Focus-group discussion, households and key informants interviews were used in data collection, also including physical observations and reviews of literature. Findings indicated that there is high dependence on agricultural production, and hence on natural resources, which makes the livelihoods of these communities potentially vulnerable to negative impacts of climate change associated with decreased agricultural productivity, food insecurity and constrained water availability. Uneven seasonal distribution of rainfall and increased temperature are major concerns for the area. Meteorological records confirm that there has been steady increase in mean maximum temperature, which affects the natural systems, influencing the phenological processes in vegetation and increasing evapo-transpiration rates, and increasing risks of crop pests and disease outbreaks. Among the local adaptation options have been the shift to more drought-tolerant and disease-resistant crop varieties and occasional migration to areas with better agricultural potential. While most societies are fundamentally adaptive and have adapted to similar climatic risks, the existing adaptation mechanisms seem to be inadequate. To facilitate local adaptations, there is a need for more information to quantify the magnitude of climate-change impacts and separate them from non-climatic factors with compounding effects. The latter is particularly important for addressing key livelihood components that seem to be most affected by climate change.

Determination of multi-mycotoxin occurrence in maize based porridges from selected regions of Tanzania by liquid chromatography tandem mass spectrometry (LC-MS/MS), a longitudinal study

Residents of certain areas of Tanzania are exposed to mycotoxins through the consumption of contaminated maize based foods. In this study, 101 maize based porridge samples were collected from villages of Nyabula, Kikelelwa and Kigwa located in different agro-ecological zones of Tanzania. The samples were collected at three time points (time point 1, during maize harvest; time point 2, 6 months after harvest; time point 3, 12 months after harvest) over a 1-year period. Ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was used to detect and quantify 9 mycotoxins: aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), aflatoxin G2 (AFG2), fumonisin B1 (FB1), fumonisin B2 (FB2), deoxynivalenol (DON), ochratoxin A (OTA) and zearaleneone (ZEN) in the samples following a QuEChERS extraction method. Eighty two percent of samples were co-contaminated with more than one group of mycotoxins. Fumonisins (FB1 + FB2) had the highest percentage occurrence in all 101 samples (100%) whereas OTA had the lowest (5%). For all three villages the mean concentration of FB1 was lowest in samples taken from time point 2. Conversely, In Kigwa village there was a distinct trend that AFB1 mean concentration was highest in samples taken from time point 2. DON concentration did not differ greatly between time points but the percentage occurrence varied between villages, most notably in Kigwa where 0% of samples tested positive. ZEN occurrence and mean concentration was highest in Kikelelwa. The results suggest that mycotoxin contamination in maize can vary based on season and agro-ecological zones. The high occurrence of multiple mycotoxins found in maize porridge, a common weaning food in Tanzania, presents a potential increase in the risk of exposure and significant health implications in children.

Bovine Tuberculosis in East Africa

The zoonotic Mycobacterium bovis is a pathogen of significance in the dairy industry in many parts of the world. Although the pathogen primarily affects cattle, it has a wide host range including humans. A cross-sectional study was carried out in three agro-ecological zones of Tanzania, namely the southern highlands zone (SHZ), eastern zone (EZ) and northern zone (NZ), to examine the status of the disease in cattle, in order to inform control measures. A total of 391, 169 and 401 cattle were tested for bovine tuberculosis (bTB) in the SHZ, EZ and NZ respectively using the Single Intradermal Comparative Cervical Tuberculin Test (SICTT). Results showed that the prevalence of bTB was higher (P<0.05) in EZ 2.37% (n = 169) compared to SHZ 1.3% (n=391) and NZ, where no positive result was recorded (n = 401). Thirty three cattle from SHZ and seven from EZ showed inconclusive results. In Kenya, 625 cattle from four sites within agro-pastoral and pastoral production systems were tested. In one area of Mwingi County, eastern Kenya, all the 161 cattle tested negative; while in the other three sites of Migori, in Nyanza, West Pokot and Laikipia in the Rift Valley, prevalence of 4-6% was obtained with SICTT. Bovine TB occurs in the region and may pose a public health threat through occupational activities and/or consumption of animal products, especially since no obvious clinical signs were observed in positive animals. Policy issues on how to deal with positive cases, creation of awareness on this important zoonotic disease, and a simple test to quickly identify sick animals in the field require urgent attention. Key Words: Agro-ecological zones, Mycobacterium bovis , Zoonoses