Institutions, Production and Marketing of maize in Zimbabwe. Case of Marondera District of Mashonaland East Province
- Authors: Mafuse, Never
- Date: 2018
- Subjects: Food security Food supply
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15687 , vital:40506
- Description: Food security situation in Zimbabwe is deteriorating despite the efforts made by the government for embarking on agrarian reforms in terms of redressing colonial imbalances and taking on the major trading investment risks. The government assured the resettled farmers that if they invest in maize production, they would not be stranded by lack of marketing services as the markets are liberalized. However, this market liberalization policy occurring in maize sector has resulted in A1 resettled farmers becoming more vulnerable to traders preying on their weaknesses as the policy is not living up to expectations and is failing to bring dramatic increases in agricultural growth. This may mean that sending children to school is a nightmare for those who depend on farming for educating their children, inadequate food in the home, unpaid loans and subsequent impoverishment. The resettled A1farmers will remain trapped in the poverty cycle as long as institutions are not corrected. The general aim of the study was to evaluate institutional factors influencing maize production and marketing by A1 resettled farmers of Marondera district in Mashonaland East province of Zimbabwe. Using a sample of 343 farmers randomly selected in Marondera District, different econometric models like Data envelopment Analysis, Cob Douglas, Binary logistic, and Tobit as well as descriptive statistics were used to analyse the data. Institutional variables were captured in two ways: as a dummy showing whether farmers have access to institutional variables and as a continuous variable indicating importance of institutions on maize production and marketing. The study found out that, most of the A1 farmers are old, with a mean age of 47 years and a maximum of 55 years of farming experience. It is also dominated by male farmers who are literate. Results also showed that most of A1 farmers from the sample are married and very few separated. These farmers sell most their maize and keep little for consumption though they are still using convectional farming methods. Most of the farmers from the sample generate their incomes from farming activities only and they have good access to market and production information as well as extension xvi messages through training .They however have poor access to financial credit and weak social capital as well as low contract farming. Results also indicated that A1 farmers pursue the formal supply chains than informal supply chains. It is noted that, A1 farmers participate in a number of markets that include agricultural inputs markets seed, fertilizers, chemicals.; credit markets which includes banks as well as labour markets which can in the form of (maricho). In terms production and marketing efficiency, the study found out that A1 farmers are technically, allocatively and economically inefficient. The maximum efficient score is 1 while the minimum score is 0.01 for both production and marketing stage. The mean scores for production stage are 0.195, 0.504 and 0.072 for technical, allocative and economic efficient respectively. The mean scores for marketing are 0.103, 0.688, and 0.068 for technical, allocative and economic efficiency respectively. Farmers are performing better at production stage than at marketing technically while there is better allocative and economic efficiency at marketing stage. Results for determinants of technical, allocative and economic efficiency at production stage showed that, cattle ownership, farming experience, access to financial credit and (member of farmer organisation) which was used as a proxy indicator for social capital ,access to information, contract farming, distance to input market ,area planted to maize and quantity of seed used influences marketing efficiency of A1 maize farmers in Marondera District. Access to credit, Access to market, distance to market, road infrastructure, farming experience and access to information influences technical, allocative and economic efficiency at marketing stage. Cooperative membership, road infrastructure, contractual farming arrangements, and access to financial credit and transport cost to market influence choice of marketing channel respectively. Finally results from the non linear cob Douglas reveals that, maize production is significantly influenced by contract with value chain actors, access to market xvii information, access to financial credit, total topdressing used , total basal fertilizer used, total herbicides used, and total area put under maize production. The results showed that, future of A1 resettled farmers depends on correcting the institutions which are of paramount importance for maize production and marketing. The study therefore recommended the government to improve institutional environment that has direct link with institutional innovations necessary for sustainable maize production and marketing. This can be done through correcting inefficiencies and ineffective institutions by creating and maintaining both environment and arrangement that will transform maize production and marketing systems to operate efficiently. The study presents policy options to address both production and marketing of maize arguing that new direction of production and marketing of maize depends on correcting dysfunctional institutions. Policy options include increasing A1 farmers access to financial credit by removing the stringent collateral requirements which are not attainable by most A1 farmers as their asset endowment is limited to non capital. Addressing imperfections in the input markets by improving the supply of chemical fertilisers and seed at affordable prices as this influences total area put under maize production. The other policy is for private companies and NGOs to offer contract farming to A1 maize farmers as this will help them to increase total area put under maize production, access to market, access to credit, and access to information and reduces long distances to purchase inputs. Introducing focused training to motivate resettled A1 farmers on formation farmer organisations as this assists in social capital which is an important asset in maize production and marketing.Improving road infrastructure by creating a fund that would be used to maintain the road rather waiting for DDF only.
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- Date Issued: 2018
Molecular systematics and biology of two closely related blowflies : Lucilia sericata and Lucilia cuprina
- Authors: Williams, Kirstin Alexa
- Date: 2015
- Subjects: Lucilia sericata , Lucilia cuprina
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5934 , http://hdl.handle.net/10962/d1017812
- Description: The greenbottle blowflies, Lucilia sericata (Meigen, 1826) and Lucilia cuprina (Wiedemann, 1830) (Diptera: Calliphoridae) are very difficult to distinguish on the basis of their external morphology. The literature suggests that these two species may be interbreeding. Sequencing two nuclear (28S rRNA and Period) and one mitochondrial (COI) gene indicated that there has been an ancient hybridization event and that mtDNA of L. sericata has become fixed in a lineage of L. cuprina through mtDNA introgression, possibly involving Wolbachia infection. This has implications for identifications of these species based on mtDNA alone. No study has shown explicitly that hybrids of L. sericata and L. cuprina can be identified morphologically. Morphological characters used to identify L. sericata and L. cuprina were scored and tested using specimens of both species and known hybrids. Discriminant function analysis of the characters successfully separated the specimens into three unambiguous groups – L. sericata, L. cuprina and hybrids. This is the first evidence that hybrids of these two species can be identified from physical characteristics.Lucilia sericata and L. cuprina have medical, veterinary and forensic importance. Knowing their distribution in South Africa would allow more effective management and utilisation of these flies. Their predicted geographic distributions in South Africa were modelled using maximum entropy analysis of selected climatic variables. The most important environmental variables in modelling their distributions were magnitude of monthly rainfall and the magnitude of the monthly maximum temperature for L. sericata, and the seasonal variation in monthly mean humidity and magnitude of monthly rainfall for L. cuprina. Both species have a widespread distribution in South Africa and one therefore cannot identify specimens of these flies by locality of capture alone.Luciliinae is a diverse and geographically widespread subfamily containing four genera - Hemipyrellia, Lucilia, Dyscritomyia and Hypopygiopsis – that all contain parasitic species ranging from saprophages to obligate parasites. The phylogenetic relationships between these genera are unclear. The 28S rRNA, COI and Period genes of 14 species of Lucilia and Hemipyrellia were partially sequenced and analysed together with 11sequences from GenBank and the Barcode of Life Database (BOLD). Lucilia sericata and L. cuprina were shown to be sister-species. Three cases of paraphylly were identified within Lucilia that affects identification of these species using mtDNA alone. Hemipyrellia consistently caused Lucilia to be paraphyletic when it was included in analyses, so Hemipyrellia should be synonymized with Lucilia. The relationships of Dyscritomyia and Hypopygiopsis to Lucilia are unclear and further studies are required. No geographic pattern was found within the different forms of parasitism within this group, but the different degrees of parasitism were phylogenetically clustered.
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- Date Issued: 2015
Purification, characterisation and application of inulinase and transferase enzymes in the production of fructose and oligosaccharides
- Authors: Mutanda, Taurai
- Date: 2008
- Subjects: Fructose Transferases Oligosaccharides
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4448 , http://hdl.handle.net/10962/d1007734
- Description: Inulin hydrolysis can occur as a result of the action of exoinulinases and endoinulinases acting alone or synergistically. Exoinulinases cleave the non-reducing β-(2, I) end of inulin releasing fructose while endoinulinases act on the internal linkages randomly to release inulotrioses (F₃), inulotetraoses (F₄) and inulopentaoses (F₅) as major products. Fructosyltransferases act by cleaving a sucrose molecule and then transferring the liberated fructose molecule to an acceptor molecule such as sucrose or another oligosaccharide to elongate the short chain fructooligosaccharide. The production of high yields of oligosaccharides of specific chain length from simple raw materials such as inulin and sucrose is a challenge. Oligosaccharides of chain length up to degree of polymerisation (DP) 5 and fructose were produced using preparations of three commercial microbial enzymes. Production of these novel oligosaccharides was achieved by employing response surface methodology (RSM) with central composite experimental design (CCD) for optimising product yield. Using a crude Novozyme 960 endoinulinase preparation isolated from Aspergillus niger, the following conditions gave a high inulooligosaccharide (lOS) yield, temperature (60 ºC), 150 g/L inulin concentration, 48 h incubation; pH 6.0 and enzyme dosage of 60 U/ml. Under these conditions, inulotrioses (70.3 mM), inulotetraoses (38.8 mM), and inulopentaoses, (3.5 mM) were produced. Response surface regression predicted similar product levels under similar conditions. The crude endoinulinase was purified through a three step purification procedure with a yield of 1.11 % and 3.5 fold purification. The molecular weight of this endoinulinase was estimated to be 68 .1 kDa by SDS-PAGE and its endoinulinase nature was confirmed by native PAGE. The purified endoinulinase was more efficient in production of lOS than the crude endoinulinase preparation. The purified endoinulinase demonstrated a high affinity for the inulin substrate (Km[subscript] 3.53 mM, Vmax[subscript] 666.67 μmol/min/ml). Pectinex Ultra SP-L, a commercial crude enzyme preparation isolated from Aspergillus aculeatus is a cocktail of several enzymes including a fructosyltransferase. The crude enzyme showed both transfructosylation and hydrolytic activity in 200 to 600 g/L sucrose. The main fructooligosaccharides produced from sucrose were l-kestose (GF₂), nystose (GF₃) and fructofuranosyl nystose (GF₄). After the first RSM, with the coded independent variables of temperature, incubation time, pH and sucrose concentration, the highest levels of GF₂, was 68.61 mM, under sucrose concentration 600 g/L, temperature 60°C, enzyme dosage 20 U/ml , pH 5.6, after 4 h incubation. A sucrose concentration of 400 g/L favoured the synthesis of high levels of GF₃ and GF₄. In the second RSM the maximal yields of GF₂, GF₃ and GF₄ were 152.07 mM, 131.38 mM and 43.99 mM respectively. A purified fructosyltransferase did not synthesise GF₄. Ammonium ions were demonstrated to enhance the yield of FOS. A mixture of glucose and fructose was used as substrate for FOS synthesis and no FOS were formed. Glucose was shown to be an end product inhibitor of the fructosyltransferase and therefore hinders the formation of high FOS yield. Fructozyme, isolated from Aspergillus ficuum is a mixture of exo and endoinulinases with the former being predominant was used for fructose production from inulin hydrolysis. The exoinulinase was purified to electrophoretic homogeneity by a three step purification procedure. The molecular weight of the enzyme was estimated to be 53 kDa with a 2 I % yield and 4.2-fold. Response surface regression was used to predict the maximum fructose levels achievable under the combinations of temperature, enzyme dosage and incubation time. A reaction time (48 h), enzyme dosage (100 U/ml) and inulin concentration (150 g/l) at pH 5.0 at 50°C gave higher fructose levels (106.6 mg/ml) using crude exoinulinase as compared to 98.43 mg/ml using the purified exoinulinase. These findings indicate that higher levels of fructose require longer incubation periods and higher inulin substrate concentrations with higher enzyme dosage. The crude exoinulinase preparation gave fairly higher levels of fructose than the purified exoinulinase and this is due to the presence of other hydrolytic enzymes in the crude preparation. The conditions established by RSM and CCO were adequate in producing high yield of oligosaccharides and fructose and can therefore be applied for their industrial production since they are in high demand due to their health benefits as prebiotics.
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- Date Issued: 2008