Category: hydroponic growing

Moreover, the African continent is also affected by a number of vector-borne zoonotic infections caused either by viruses , Rift Valley Fever and Yellow Fever or by bacteria , which require parasitological and entomological expertise to be effectively addressed, due to their vectoral components . Indeed, recognising the parasitological/entomological constituents in the epidemiology of these infections is essential as it helps identifying potential arthropod or vertebrate reservoirs, thus ultimately preventing and controlling the diseases in humans and animals. In Uganda, for example, when it was first encountered, in 2013, CCHF was initially feared to be the more deadly Ebola , which has occasionally crossed the country’s border with the Democratic Republic of the Congo . Ever since, CCHF has occurred in the country in the form of outbreaks within or in the proximity of the “cattle corridor”, a region spanning northeastern, central and southwestern districts, known indeed for the density of its cattle herds . With most cases being associated with exposure to bites of ticks who have fed on viraemic cattle or ruminant hosts , the effective control of this infection could be achieved through the rollout of strategic targeted tick control programmes and the sensitisation of the general public and farming communities on the epidemiology of CCHF.

Considering that the same cattle corridor witnesses sporadic cases of mosquito-borne RVF , whose reservoir is also represented by ruminants , One Health efforts in this area should opt for the use of “arthropocidal” molecules, halting both ticks and mosquitoes, rather than merely “acaricidal” products or “insecticidal” ones .Moreover, the role of “companion” animals or non-livestock species, such as dogs and cats, is also critical for certain parasitic zoonoses in Africa. In addition to their involvement in a number of NTDs , these species are also implicated in the epidemiology of several zoonotic geohelminths such as Toxocara spp., Ancylostoma spp. and Strongyloides stercoralis, and cestodes , entailing direct or indirect transmission through an intermediate host . The frequent freeroaming behaviour of dogs and cats, typically in rural milieus across Africa , coupled with the usually poor hygiene and water sanitation of such settings, can particularly favour the spread of these parasitoses and enhance exposure risks in humans and other animal species. In addition, with the size of middle class rising in the continent , ownership of dogs and cats as “pets” may potentially increase in urban areas in the next decades, highlighting the importance of parasite control also in urban and peri-urban sites, where encounters between “owned” and “free-roaming” animals, and their excretions, may occur.

Furthermore, the contribution of wildlife needs also to be considered, either as definitive or intermediate hosts or even reservoirs of zoonotic parasites . Therefore, in order to be fully and durably effective, One Health initiatives tackling parasitic conditions should aim to tackle all final, intermediate, potentially vector and even paratenic or transport hosts involved in life cycles of target aetiological agents. Overlooking even a single host species, wildlife included, can indeed cause the reappearance or impede the elimination tout court of cases of infection or disease in certain other hosts, despite generous control efforts being addressed towards them.Should the One Health approach be envisaged only in the case of zoonotic parasitic or arthropod-borne infections that are shared between humans and animals? This concept paper advocates for a more comprehensive assessment of parasites and vectors in this paradigm. The health of livestock in Africa is indeed undermined by several parasites or arthropods that, although not zoonotic per se, cause major chronic deterioration and productivity losses, being responsible for low body condition scoring, poor protein conversion and, overall, scarce production .

In the case of cattle, for instance, gastrointestinal nematodes, ticks and tick-borne infections and animal African trypanosomiasis are the most important examples to be incriminated in these regards . The productivity losses that they entail are therefore inextricably connected with the continent’s food insecurity, especially considering that the largest bulk of Africa’s food production is used for local consumption . With food insecurity being recognised as a global health challenge , all its major causes in the animal sources should be thoroughly investigated and tackled under the One Health lens. This applies also to animals’ and livestock parasitic infections, given the burden they pose, ultimately, to human sustainment and nutrition. As the OIE puts it, “pathogens of animal origin that are not transmissible to humans, but which have a severe impact on the production of animal protein, should not be neglected either, particularly in developing countries. In fact, they can lead to production losses and a reduction in the available food supply, leading to serious public health problems caused by food shortages and protein deficiencies” .

The activity of DAHPS was measured at 549 nm. Regarding PAL, it was extracted in 1 mL of 200 mM sodium borate buffer and then evaluated by measuring the production of trans-cinnamic acid at 290 nm. For centuries, Cannabis sativa L. has been widely used around the world for various applications . These days, interest has been focused on medicinal and recreational facets, furthering commercial expansion. With Canada recently adopting the more globally appreciated view of cannabis, there exists an ever evolving, multi-billion-dollar industry focused on vegetative propagation . Despite the reliance on clonal propagation, there is a continual need to germinate seeds to select new elite genotypes, perform pheno-hunting, as well as supporting breeding programs. To select new elite genotypes, plants are started from seed .

During the vegetative phase of growth, a cutting is taken and maintained as a vegetative plant while the seedling is grown to maturity. Once the elite genotypes are selected, the cutting is then used as a source to propagate the clonal line. Maintaining the large population of cuttings during the phenotyping exercise represents a significant cost to producers and leaves the cutting derived mother plants exposed to insects and diseases. To address the issues of insect, disease, and viral infections in mother plants, many producers use plant tissue culture to ensure that they are starting with clean material. Forthis process, nodal segments are disinfected and established in culture, a time consuming and relatively expensive endeavor. Once the seedlings are established and multiplied, micropropagated clones can be transferred into the growth facility and cultivated to maturity to identify elite genotypes. After selecting the elite genotypes, the in vitro parent material would be available for clonal propagation. This approach would greatly reduce the amount of space required for selecting new cultivars and provide a ready source of clean planting material once elite genotypes are identified.

However, this approach requires an effective in vitro seed germination protocol with high germination speed and frequency. An efficient in vitro seed germination system would also support downstream biotechnologies in which seedling-derived tissues are preferred .We previously reported the effect of different types and strengths of media in addition to carbohydrate types and levels as primarily important factors contributing to in vitro cannabis seed germination indices and morphological seedling traits . Our results demonstrated that maximum germination percentage was achieved with 0.43 strength mMS medium and 2.3% sucrose . While the germination rate was over 80%, this was after 40 days of culture. Typically, the cannabis seed germinates within several days in the greenhouse/growth room, suggesting that something during the disinfection process was interfering with subsequent germination. To improve our previous protocol, we hypothesize that optimizing the disinfection protocol and seed scarification would increase the speed and frequency of seed germination. As with most aspects of a tissue culture system, in vitro disinfection is a complex and non-linear process that is affected by numerous factors such as disinfectant and contaminant types and levels, media pH, immersion time, temperature, and theirinteractions .

In the disinfection process, the concentration of disinfectants plays a conflicting dual role relating to contamination frequency and seed viability. Higher disinfectant concentrations generally lead to a greater control over contaminants; however, lower seedling viability is often the trade-off. Therefore, it is necessary to optimize the disinfection process. The disinfection process cannot be represented by a simple stepwise algorithm, especially when the datasets are highly imbalanced and noisy . Therefore, artificial intelligence models combined with optimization algorithms such as a genetic algorithm can be employed as an efficient and reliable computational method to inter-pret, forecast, and optimize this complex system . This strategy has been successfully used for modeling and optimizing different tissue culture systems, including in vitro decontamination, shoot proliferation, androgenesis, somatic embryogenesis, secondary metabolite production, and rhizogenesis . Ivashchuk et al. employed multilayer perceptron and radial basis function as two well-known artificial neural networks for modeling and predicting the effect of different disinfectants and immersion times for Bellevalia sarmatica, Echinacea purpurea, and Nigella damascene explant decontamination. They reported that both algorithms were able to accurately model and predict the disinfection process . In another study, Hesami et al. applied a hybrid MLP and non-dominated sorting genetic algorithm-II for the modeling and optimization of disinfectants and immersion times for chrysanthemum leaf segment decontamination. It was reported that MLP-NSGA-II had a high performance to predict and optimize the system .

In 1991, the Brazilian national and state research institutions in coordination with CIAT, had initiated a 5-year project for breeding cassava in drier tropics and subtropics with funds from the International Fund For Agriculture Development . Cassava germplasm from northeastern Brazil and the north coast of Colombia was initially screened at four semiarid sites in northeastern Brazil, characterized by extended drought for several months, hot weather, and sandy infertile soils with presence of pests and diseases . Some accessions were selected for their broad adap- tation across sites to contribute in a recombination and selection program . Yields of selected clones at 12 months and 18 months after planting demonstrate the high potential of cassava in these drier areas.

Also, some progenies, via hybridization, have been developed and sent to ITTA, Nigeria, for adaptation and selection under drier areas in sub-Saharan Africa . Farmers had participated in evaluating and selecting adapted materials that resulted in rapid acceptance and, consequently, in the release of several improved clones . The research reviewed here on cassava productivity, ecophysiology, breeding, and responses to environmental stresses was conducted in collaboration with a multidisciplinary team at CIAT. Under favorable environments in lowland and mid-altitude tropical zones with near-optimal climatic and edaphic conditions for the crop to realize its inherent potential, cassava is highly productive in terms of root yield and total biological biomass, conferring a competitive advantage over other tropical energy crops. Under stressful environments with extended drought of several months and low-fertility soils, where major cereal and legume crops might fail, cassava produces reasonably well.

This inherent capacity to tolerate complex stresses is supported by several morphological, physiological and biochemical mechanisms and traits, such as long leaf life, tight stomatal control over gas exchange, high photosynthetic potential and extensive fine root systems. Core germplasm was characterized and several clones tolerant to water stress and low-fertility soils were identified to breed for drier areas in Africa and Latin America. Selection for nutrient use efficient shortto-medium cassava was found to be advantageous for soil fertility conservation while retaining yield potential. Modeling predicts the suitability of cassava in globally warming climate versus other food crops, confirming its high level of tolerance . Cassava has high optimum temperature for photosynthesis and growth, and responds positively to elevated CO2 that point to its potential as food, feed and energy crop in tropical and subtropical zones adversely affected by climate changes. Because of its high costs using sophisticated methodology, currentclimate research is still confined within developed temperate zones .

Yet, there is an urgent need to conduct climate research in representative tropical ecosystems where GCMss cenarios predict the worst consequences for agricultural productivity and food security . The use of the Free Air CO2 Enrichment technology in combination with rain shelters which facilitates evaluating interactions of CO2 with soil water status , may further enhance developing improved cassava cultivars adapted to increasing atmospheric CO2. Moreover, temperature influences may be studied under field conditions using the “Temperature Free-Air Controlled Enhancement ” technique, as was recently described and used at U.S. Arid-Land Agricultural Research Center, USDA, Maricopa, Arizona . Developed countries, who are the main polluters of the atmosphere, via excessive carbon emissions, must shoulder the costs of climate research in tropical and subtropical regions. Oil-rich Arabian/Persian Gulf States should take the lead in supporting developing countries to cope with-and-adapt-to consequences of warming climate. Molecular biology technology is also needed with focus on applications into crop improvement.

For example, this technology is useful for genetically transferring simple qualitative traits controlled by one or two genes, as already had been demonstrated by the successful production and use of insect-resistant transgenic commercial crop cultivars containing the soil bacterium, Bacillus thuringiensis genes that produce the toxic Cry proteins. In contrast, quantitative multigenic traits such as tolerance/resistance to compound abiotic-stresses are unlikely to be easily amenable to genetic engineering via inserting few exotic genes. These traits when expressed at the whole organism level are mostly attributed to a range of morphological, anatomical, physiological and biochemical characteristics and mechanisms. So far, modest advances at the experimental levels were recently reported for the use of genetic molecular markers in cassava selection and breeding efforts for developing drought-tolerant cultivars .

A serious problem, however, yet lies in the early identification of dispersive soils . In spite of all the knowledge obtained over the years, there is still no fast, simple and dependable mean of conclusively recognizing dispersive soils. Many methods have been suggested including the pinhole, double hydrometer, crumb and chemical tests, individually or in group. These, but, have not always been totally credible and it looks like that the cause sets in the factual testing procedures. The standard testing procedures for the Soil Conservation Service double hydrometer test, the pinhole test, crumb test and chemical analyses have lately been studied and problems/abnormalities identified. Although no discussion concerning these anomalies has been discovered in the literature, the recent testing proposes that many of these deficiencies may have been looked out during past routine investigations. This paper summarizes a proportional study including the testing of three specimen utilizing one standard laboratory test, namely the SCS double hydrometer test and discusses some potential means of conquering the problems identified.

The other tests have been discussed separately. SCS double hydrometer or dispersion soil test has been identified as one of the most suitable tests for classifying dispersive soils. The test assesses the dispersibility of a soil by measuring the natural propensity of the clay fraction to go into annotate in water. The procedure involves the estimation of the percentage of particles in the soil that are finer than 0.005 mm utilizing the standard hydrometer test. A parallel test is also carried out, in which no chemical dispersant is added and the solution is not mechanically excited. The quantity of particles finer than 0.005 mm in the parallel test is explicit as a percentage of this fraction determined in the standard test, which is defined as the dispersion ratio or dispersivity of the soil . Dispersion ratios greater than 50% are observed extremely dispersive, between 30% and 50% are moderately dispersive, between 15% and 30% are a little dispersive and less than 15% are non-dispersive . Similar systems with various limits were used by, and the dispersion test was first described by Volk  as a means of determining the potential dispersive of soils.

The test has since been utilized extensively in this concern with minor modifications. Volk’s test contrasts the weight of soil grains, 0.005 mm or smaller that slaked free when air-dried lumps of soil were soaked in silent distilled water with that of the complete soil. This was shown as the percentage dispersion. The pipette method itself was announced by Middleton in 1930 as a means of determining the erosion potential of a soil. The difference in the methods was that the samples collected in the pipette depend on particles of a maximum diameter of 0.05 mm . Volk’s method was, however, chosen because studies in the southwest of the United States point out that the dispersion of the clay fraction was more significant in assessing the piping potential of soils . The SCS involvement in earth dam construction in the United States reproduces in the 1940’s and early 1950’s. It was during this time that the test procedure was appropriate to utilize a hydrometer to instate a pipette .This study was performed in Sulaimani Governorate to determine the effect of ten land use and clay content on dispersion ratio. The soil samples from 0 – 30 cm depth were collected from different locations. All soil samples were air dried, sieved through a 2 mm physical properties were measured such as particle size distribution by the pipette method, bulk density by Clod method. A single point using water under isothermal condition was measured the according to . Chemical properties were measured like soil organic matter which determined by the Walkley-Black method  and calcium carbonate by titration method. Correlation and regression were used to analyze the relationship between land use and some soil parameters of the samples .

Analysis of variance for complete randomized design was used to compare the influence of the land usage types on the measured soil properties. DUNCAN at P < 0.5 level was used to separate the mean where applicable.The soil texture of the study area was significantly affected by land use. Data obtained in Table 1 showed the variation in sand, silt and clay fraction of the soil. The result shows that the textural class across all the land use types of the study area is different soil texture, indicating the different of parent material. The result is in agreement with . However, over a very long period of time, paedogenesis processes such as erosion, deposition, eluviations, and weathering can change the soil texture.