Agrochemicals use in horticulture industry in Tanzania and their potential impact to water resources

The objective of this review was to analyze the existing information on the use of agrochemicals (Fertilizers and Pesticides) in the Tanzanian  horticulture industry especially the Northern regions and their potential to impacting water resources. Agrochemicals play an important role in  horticulture, and have been widely used in Tanzania for crop protection and increasing productivity. Apart from these benefits, agrochemicals have the potential to impair the quality of water resources for different end uses. Majority of communities in Tanzania depend on surface water from rivers and lakes for potable uses such as washing, drinking and domestic  animals also drink from these sources. Reports from studies done in Northern Tanzania have indicated the presence of significant levels of pesticides, phosphates and nitrates in surface and groundwater. It is  apparent that most of the horticultural farms in Northern Tanzania are located on gently sloping land adjacent to water bodies. Thus discharges of wastewaters from horticulture farms may affect the quality of water  resources through run-off and groundwater through infiltration if proper management of the agrochemicals is not well adhered to. The  agrochemicals that have been widely used and identified as potential environmental pollutants from their use as horticultural chemicals are  reviewed. The potentially adverse impacts of these agrochemicals to water resources are discussed. The review concludes with a discussion of the directions for further investigation. Keywords: Pesticides, fertilizers, wastewater, horticulture, environmen

Studies of the genetics of inheritance of stem rust resistance in bread wheat

Pgt race TTKSK (Ug99) has a wide virulence range with respect to currently grown wheat cultivars worldwide. Aspects of migration, mutation, recombination and selection in the pathogen have led to previously deployed stem rust resistance genes being ineffective. Race TTKSK has further evolved to acquire virulence for resistance genes such as Sr24 (race Ug99 + Sr24) and Sr36 (Ug99 + Sr36). Five resistant wheat lines (KSL-2, KSL-3, KSL-5, KSL-12 and KSL-19) which were resistant in tests during 2008, 2009 and 2010 were used as parents in crosses with stem rust susceptible line CACUKE to develop genetic populations for determining the inheritance of resistance to stem rust. F3 populations were evaluated at KARI Njoro in the 2012 off season and 2012 to 2013 main season. The adult plant stem rust responses were scored using the modified Cobb’s scale. The F2:3 lines of population(s) exhibiting qualitative variation were grouped as homozygous resistant (HR), segregating (Seg) and homozygous susceptible (HS). Heavy disease pressure was present during the cropping seasons with the check CACUKE displaying 90% susceptibility. Chi square analysis revealed that the segregation data in the parent KSL-2 did not deviate significantly from the single gene model (1:2:1) suggesting that the resistance to stem rust is conditioned by a single dominant gene. The Chi square test also revealed that the stem rust resistance in the parents KSL-3, KSL-5, KSL-12 and KSL-19 was conditioned by two genes. The families from the KSL-2 and KSL-3 crosses also segregated for the presence of the pseudo black chaff implying that the Sr2 gene could be present in the background of these wheat parents. The superior transgressive segregants identified in these crosses will be used in breeding.Keywords: Genetic, wheat, gene, resistanceAfrican Journal of Biotechnology Vol. 12(21), pp. 3153-315

First Report of Rice yellow mottle virus in rice in Malawi

International audienceFirst report of Rice yellow mottle virus in rice in Malaw

LEVERAGING FROM GENOTYPE BY ENVIRONMENT INTERACTION FOR BREAD WHEAT PRODUCTION in EASTERN AFRICA

Developing high yielding and stable genotypes for wide and specific adaptation is important in wheat ( Triticum aestivum L.) production. The objective of this study was to exploit the gains from genotype by environment interaction for increased bread wheat production in eastern Africa. Thirty-three advanced bread wheat lines, along with two check varieties (Danda\u2019a and Hidasse) were evaluated at ten locations in Ethiopia and Kenya. The experiment was laid out in alpha lattice design in three replications. The analysis of variance for AMMI model of grain yield showed that environment, genotypes and genotype by environment interaction (GEI) effects were highly significant (P<0.01), and accounted for 62.4, 4.8 and 15.8% of the total sum of squares variations, respectively. High environmental and significant GEI indicated that the environment had major influence for inconsistent performance. Grain yield of the genotypes ranged from 1.58 t ha-1 (G30) to 9.05 t ha-1 (G31). Genotypes G31, G18 and G35 were the best performing lines across environments. The AMMI biplot, using the first two principal components, showed that testing sites Njoro and Arsi-Robe highly discriminated the tested genotypes. Njoro was negatively interacting with high yielding genotypes, and was a different environment from any of the testing locations of Ethiopia for these sets of genotypes. It may be difficult to develop high yielding and stable varieties for the two countries, but one should look for specific adaptation. Genotypes G31 and G18 produced high grain yield, with low stability across locations which were favouring high yielding environments. However, G21 and G8 had above mean grain yield and good stability across locations. Therefore, wheat breeding for specific adaptability is very important to exploit the genetic advantage of specific genotypic performances across the region. However, extensive testing considering many locations across East African countries is vital for delineating and exploiting wheat environments for marked developments.Le d\ue9veloppement de vari\ue9t\ue9s stables et a rendements \ue9lev\ue9s dans le but d\u2019adoption a grande \ue9chelle, est important dans la production du bl\ue9 tendre ( Triticum aestivum L.). L\u2019objectif de cette \ue9tude est d\u2019exploiter l\u2019effet de l\u2019interaction entre g\ue9notypes et environnements (IGE) pour accroitre la production du bl\ue9 tendre en Afrique de l\u2019Est. Trente-trois lign\ue9es avanc\ue9es de bl\ue9 tendre ensemble avec deux vari\ue9t\ue9s de r\ue9f\ue9rence (Danda\u2019a and Hidasse) ont \ue9t\ue9 \ue9valu\ue9es dans dix locations. Le plan exp\ue9rimental \ue9tait en treillis alpha avec trois r\ue9p\ue9titions. La m\ue9thode de l\u2019interaction des effets additifs and multiplicative (AMMI) avait \ue9t\ue9 utilis\ue9e pour le rendement en grain. L\u2019analyse des variances selon ce mod\ue8le a montr\ue9 que l\u2019environnement, le g\ue9notype et l\u2019interaction des deux ont des effets significatifs sur le rendement en grains (P<0,01), et contribuent respectivement, 62,4\ua0; 4,8 et 15,8% \ue0 la variation totale. Un effet important de l\u2019environnement et une interaction significative indiquent que l\u2019environnement a un r\uf4le majeur dans les diff\ue9rences de rendements. Les rendements en grains des g\ue9notypes testes varient de 1.58 t ha-1 (G30) a 9.05 t ha-1 (G31). Les g\ue9notypes G31, G18 et G35 \ue9taient de fa\ue7on g\ue9n\ue9rale, les plus performants. Le biplot g\ue9n\ue8re par AMMI a montr\ue9 que les sites Njoro and Arsi-Robe discriminent nettement les g\ue9notypes test\ue9s. Njoro \ue9tait n\ue9gativement corr\ue9l\ue9 avec les g\ue9notypes a rendement \ue9lev\ue9 et constituait un environnement diff\ue9rent de toutes les autres locations de l\u2019Ethiopie ou ces g\ue9notypes ont \ue9t\ue9 testes. Il peut s\u2019av\ue9rer difficile de d\ue9velopper des vari\ue9t\ue9s \ue0 haut rendement et stable dans les deux pays, mais l\u2019on doit rechercher des vari\ue9t\ue9s adapt\ue9es \ue0 chaque milieu. Les g\ue9notypes G31 et G18 ont eu des rendements \ue9lev\ue9s mais n\u2019ont pas \ue9t\ue9 stables dans les milieux qui se sont av\ue9r\ue9s \ue0 haut rendement. N\ue9anmoins, G21 et G8 ont eu des rendements plus \ue9lev\ue9s que la moyenne et se sont montres stables d\u2019un milieu \ue0 un autre. Il s\u2019ensuit donc que le d\ue9veloppement de vari\ue9t\ue9 de bl\ue9 tendre adapt\ue9 \ue0 chaque milieu serait une bonne approche pour une exploitation efficiente des avantages g\ue9n\ue9tiques des g\ue9notypes \ue0 haute performance. N\ue9anmoins, il est important de faire des essais extensifs prenant en compte plusieurs localit\ue9s des pays de l\u2019Afrique de l\u2019Est afin d\u2019explorer et identifier les milieux propices au bl\ue9 tendre

The Association Between Social Networks and Self-rated risk of HIV Infection among Secondary School Students in Moshi Municipality, Tanzania.

Abstract This study describes the social networks of secondary school students in Moshi Municipality, and their association with self-rated risk of human immunodeficiency virus (HIV) infection. A cross-sectional analytical study was conducted among 300 students aged 15-24 years in 5 secondary schools in Moshi, Tanzania. Bonding networks were defined as social groupings of students participating in activities within the school, while bridging networks were groups that included students participating in social groupings from outside of the school environs. A structured questionnaire was used to ask about participation in bonding and bridging social networks and self-rated HIV risk behavior. More participants participated in bonding networks (72%) than in bridging networks (29%). Participation in bridging networks was greater among females (25%) than males (12%, p < .005). Of 300 participants, 88 (29%) were sexually experienced, and of these 62 (70%) considered themselves to be at low risk of HIV infection. Factors associated with self-rated risk of HIV included: type of school (p < .003), family structure (p < .008), being sexually experienced (p < .004), having had sex in the past three months (p < .009), having an extra sexual partner (p < .054) and non-condom use in last sexual intercourse (p < .001), but not the presence or type of social capital. The study found no association between bonding and bridging social networks on self-rated risk of HIV among study participants. However, sexually experienced participants rated themselves at low risk of HIV infection despite practicing unsafe sex. Efforts to raise adolescents' self-awareness of risk of HIV infection through life skills education and HIV/acquired immunodeficiency syndrome risk reduction strategies may be beneficial to students in this at-risk group

Routine delivery of artemisinin-based combination treatment at fixed health facilities reduces malaria prevalence in Tanzania: an observational study

BACKGROUND Artemisinin-based combination therapy (ACT) has been promoted as a means to reduce malaria transmission due to their ability to kill both asexual blood stages of malaria parasites, which sustain infections over long periods and the immature derived sexual stages responsible for infecting mosquitoes and onward transmission. Early studies reported a temporal association between ACT introduction and reduced malaria transmission in a number of ecological settings. However, these reports have come from areas with low to moderate malaria transmission, been confounded by the presence of other interventions or environmental changes that may have reduced malaria transmission, and have not included a comparison group without ACT. This report presents results from the first large-scale observational study to assess the impact of case management with ACT on population-level measures of malaria endemicity in an area with intense transmission where the benefits of effective infection clearance might be compromised by frequent and repeated re-infection. METHODS A pre-post observational study with a non-randomized comparison group was conducted at two sites in Tanzania. Both sites used sulphadoxine-pyrimethamine (SP) monotherapy as a first-line anti-malarial from mid-2001 through 2002. In 2003, the ACT, artesunate (AS) co-administered with SP (AS + SP), was introduced in all fixed health facilities in the intervention site, including both public and registered non-governmental facilities. Population-level prevalence of Plasmodium falciparum asexual parasitaemia and gametocytaemia were assessed using light microscopy from samples collected during representative household surveys in 2001, 2002, 2004, 2005 and 2006. FINDINGS Among 37,309 observations included in the analysis, annual asexual parasitaemia prevalence in persons of all ages ranged from 11% to 28% and gametocytaemia prevalence ranged from <1% to 2% between the two sites and across the five survey years. A multivariable logistic regression model was fitted to adjust for age, socioeconomic status, bed net use and rainfall. In the presence of consistently high coverage and efficacy of SP monotherapy and AS + SP in the comparison and intervention areas, the introduction of ACT in the intervention site was associated with a modest reduction in the adjusted asexual parasitaemia prevalence of 5 percentage-points or 23% (p < 0.0001) relative to the comparison site. Gametocytaemia prevalence did not differ significantly (p = 0.30). INTERPRETATION The introduction of ACT at fixed health facilities only modestly reduced asexual parasitaemia prevalence. ACT is effective for treatment of uncomplicated malaria and should have substantial public health impact on morbidity and mortality, but is unlikely to reduce malaria transmission substantially in much of sub-Saharan Africa where individuals are rapidly re-infected.Financial support for IMPACT-Tz came primarily from CDC, the U.S. Agency for International Development and the Wellcome Trust

Nutrients’ distribution and their impact on Pangani River Basin’s ecosystem – Tanzania

Research Articles published by Taylor & Francis GroupSurface and groundwater from Pangani River Basin (PRB) were sampled in dry and wet seasons, analysed for dissolved organic and inorganic nutrients (N, P, Si and Urea). There was spatial and seasonal nutrients’ variability, with enrichment of dissolved inorganic fractions accumulated from natural and anthropogenic sources. Silicates increased in dry season, whereas nitrate, ammonium, phosphate and urea increased in wet season; except for phosphate, other nutrients increased from upstream to the river mouth. High rate of chemical weathering possibly due to tropical climate and volcanic rocks has caused PRB to have higher concentration of silicates than average freshwater African Rivers. Contribution of PRB to the coast of Indian Ocean was 2.6, 39.0, 45.2, 67.4 and 5444.8 (mol/km2/yr) for nitrite, phosphate, ammonium, nitrate and silicates, respectively, which were lower than most of the tropical rivers in the world. Levels of nitrate and phosphate for most of the stations were higher than recommended levels for aquatic ecosystem health. Furthermore, observed hypoxia condition in some stations threatens aquatic life. This study recommends the efficient use of fertilizers to reduce nutrients’ uptake into the lakes and rivers so as to meet the recommended level for aquatic and human health

Suitability of selected vegetable tannins traditionally used in leather making in Tanzania

This research article published by Elsevier Ltd., 2020The use of chromium salt has dominated in tanning industry worldwide due to its high versatility in quality leather production. However, Environmental concerns of chromium have shifted the interest of current research to chrome-free and greener chemical processing options. Vegetable tannins, especially when used in combination with some benign metals, have been proven to be environmentally safe and manageable, while producing good quality leather with similar shrinkage temperature as that of chromium tanned. As such, shortage of vegetable tannin supply necessitates characterization of non-commercialized sources locally available to feed cottage tanneries. In the present work, extracts from Acacia mearnsii, Acacia xanthophloea, Euclea divinorum and Euclea racemosa, leached by simple technique at 30–80 °C temperature range were characterized for extract yield, tannin, total flavonoid and phenolic contents, crosslinking ability as well as properties of tanned leather. Results indicate that at 50 °C extraction temperature, A. xanthophloea bark gave extract with properties similar to that of A. mearnsii (commercialized source of tannin). Extract from E. divinorum bark contain fairly less extract yield, tannin, total flavonoid and phenolic contents than that of A. mearnsii, but had good crosslinking ability and tanning performance similar to that of A. mearnsii when used in combination with Aluminium Sulphate [Al2(SO4)3]. The 2% Aluminium Oxide (Al2O3) equivalent was established to be optimal dose of Al2(SO4)3 for extract pre-treatment. E. racemosa barks have high extract yield, but very low crosslinking ability, making it not suitable as a tannin source. This work provides useful information on the potential source of tannins for cottage leather industries in Tanzanian and beyond

A New Horned Crocodile from the Plio-Pleistocene Hominid Sites at Olduvai Gorge, Tanzania

BACKGROUND: The fossil record reveals surprising crocodile diversity in the Neogene of Africa, but relationships with their living relatives and the biogeographic origins of the modern African crocodylian fauna are poorly understood. A Plio-Pleistocene crocodile from Olduvai Gorge, Tanzania, represents a new extinct species and shows that high crocodylian diversity in Africa persisted after the Miocene. It had prominent triangular "horns" over the ears and a relatively deep snout, these resemble those of the recently extinct Malagasy crocodile Voay robustus, but the new species lacks features found among osteolaemines and shares derived similarities with living species of Crocodylus. METHODOLOGY/PRINCIPAL FINDINGS: The holotype consists of a partial skull and skeleton and was collected on the surface between two tuffs dated to approximately 1.84 million years (Ma), in the same interval near the type localities for the hominids Homo habilis and Australopithecus boisei. It was compared with previously-collected material from Olduvai Gorge referable to the same species. Phylogenetic analysis places the new form within or adjacent to crown Crocodylus. CONCLUSIONS/SIGNIFICANCE: The new crocodile species was the largest predator encountered by our ancestors at Olduvai Gorge, as indicated by hominid specimens preserving crocodile bite marks from these sites. The new species also reinforces the emerging view of high crocodylian diversity throughout the Neogene, and it represents one of the few extinct species referable to crown genus Crocodylus