Thesis (MComm)—Stellenbosch University, 2015. / ENGLISH ABSTRACT: The second step in the study was to empirically measure the competitive performance of the date industry based on this trade orientation, using the relative trade advantage (RTA) method. Trade data from FAOSTAT and Trademap were used. Since 2001, the Namibian date industry has consistently recorded positive trends with RTA values ranging between 0.40 and 4.0. When compared to other international competitors, the results indicate that Tunisia is by far the most competitive country, with RTA values ranging between 278 and 391. Namibia’s date industry leads competitors such as South Africa, the USA, Kenya, Australia and India. In step 3, an industry-wide survey was conducted among executive-level industry role players, which identified 72 factors influencing competitive performance. The 72 factors were rated and analysed through chi-square and one-way analysis of variance (ANOVA) in terms of their current impact as enhancing or constraining and also in terms of their relevance to the industry. The results revealed that all factors were rated highly relevant (i.e. important) to the industry’s competitive performance levels, with 47 percent playing an enhancing role, while 43 percent were constraining competitive performance in the Namibian date industry. Differences between views on the current impact and long-term relevance of factors provided a ‘performance gap’ that the industry had to attend to strategically in order to improve competitive performance. The top three most enhancing factors are the substantial size of the international date market, the availability of unskilled labour, and the suitability of Namibian date production (project) locations. The highest rated constraining factors were identified as: the lack of privately funded scientific research capacity, the slow growth and small size of local markets, and insufficient industry expenditure on research and development (R&D). The fourth step applied Porter’s theory of competitiveness (1990; 1998) to derive the industry determinants of competitive performance. The 72 factors were grouped into the six Porter diamond determinants. Principal component analysis (PCA) was undertaken to identify variations and consensus in the views of respondents with respect to the relevance and impact of factors identified for each determinant. The results revealed that there were variations in opinions with regard to 52 factors and consensus on 20 factors, influencing the industry’s competitive performance. In analysing opinions on the impacts and long-term relevance of the identified factors, two value chain clusters were identified, viz. those opinions or respondents directly involved in the production processes of dates (cluster 1); and those providing supporting functions to the production process (cluster 2). The results indicate that although there are similarities in the opinions within the date industry value chain, important differences do exist and must be noted in strategic planning process by the industry. Differences were recorded with regard to access to quality technology, obtaining long-term credit, diversification in the international market, cost of specialised technology services, the effect of legal and political factors on the industry’s strategic position, the country’s black economic empowerment (BEE) policy and health cost implications. In step 5, the most important findings from steps 3 and 4, together with views gathered from a date industry information session (the DIS) and personal interviews, were included in a strategic decision matrix aimed to develop industry-level proposals to improve competitive performance. This matrix listed constraining factors for which a large degree of industry-level consensus was recorded, together with those actions that could improve performance immediately. Proposals highlighted were: focusing on human resources and skills development; cost-sharing activities; public-private partnerships in the development of project-level socio-economic investment packages, investing in long-term research and development (R&D); upgrading export facilities; local market development and improved collaboration with national retailers; reduction of marketing costs; export-market diversification; developing representative industry-level institutions and an industry-level strategic plan; and mobilising government-level support more effectively in order to create a conducive environment for the industry to compete successfully. / AFRIKAANSE OPSOMMING: Hierdie studie het die mededingende prestasie van die Namibiese dadelbedryf vanaf 2001 tot 2013 ondersoek. In die studie is die konvensionele raamwerk vir die mededingendheidsanalise van agribesigheid (verwys na Ismea, 1999; Esterhuizen, 2006; Van Rooyen et al., 2011; Boonzaaier, 2014; Jafta, 2014) verfyn om die geldigheid van die vrae wat die respondente geantwoord het en die verskille in hulle response teenoor huidige impakte en langtermyn relevansie te oorweeg. Opinies vanuit die waardeketting van die dadelbedryf is ook ingesluit in die ontledings. Die konsep van mededingendheid is eerstens gedefinieer, gebaseer op die belangrikheid van internasionale handel vir die Namibiese dadelbedryf, as die vermoë van die dadelbedryf om sy produkte op ’n volhoubare basis in beide binnelandse en internasionale markte te verhandel en, as sulks, te kan voortgaan om skaars hulpbronne soos grond, arbeid, tegnologie, bestuurstalente en kapitaal te lok en terselfdertyd ten minste die geleentheidskoste van opbrengste op hulpbronne verbruik, te verdien (aangepas uit die werk van Freebairn, 1986; Esterhuizen, 2006; Van Rooyen et al., 2011). Die tweede stap in die studie was om die mededingende prestasie van die dadelbedryf empiries te meet op grond van hierdie handelsoriëntasie deur gebruik te maak van die relatiewe handelsvoordeel (relative trade advantage (RTA)) metode. Handelsdata afkomstig van FAOSTAT en Trademap is gebruik. Sedert 2001 het die Namibiese dadelbedryf konsekwent positiewe tendense vertoon, met RTA-waardes wat gewissel het tussen 0.40 en 4.0. In vergelyking met ander internasionale mededingers toon die resultate dat Tunisië verreweg die mees mededingende land is, met RTA-waardes van tussen 278 en 391. Namibië se dadelbedryf loop egter voor teen mededingers soos Suid-Afrika, die VSA, Kenia, Australië en Indië. In stap 3 is ’n bedryfswye opname onder bestuursvlak- rolspelers onderneem. Hierin is 72 faktore geïdentifiseer wat mededingende prestasie beïnvloed. Die 72 faktore is geëvalueer en deur middel van chi-kwadraat en eenrigting analise van variansie (ANOVA) geanaliseer in terme van hulle huidige impak as óf versterkend óf stremmend, en ook in terme van hulle relevansie vir die bedryf. Die resultate het getoon dat al die faktore as hoogs relevant (m.a.w. belangrik) vir die bedryf se mededingende prestasievlakke geëvalueer is, met 47% wat ’n versterkende rol gespeel het, terwyl 43% mededingende prestasie in die Namibiese dadelbedryf gestrem het. Verskille tussen die sienings oor die huidige impak en die langtermyn relevansie van die faktore het ’n ‘prestasiegaping’ voorsien wat die bedryf strategies aan aandag moet skenk om die mededingende prestasie te verbeter. Die drie top versterkende faktore was die grootte van die internasionale dadelmark, die beskikbaarheid van ongeskoolde arbeid en die gepastheid van die dadelproduksie (projek)-gebiede. Die stremmende faktore wat die belangrikste geag is, is geïdentifiseer as die gebrek aan privaatbefondsde wetenskaplike navorsing, die baie stadige tempo van groei in plaaslike markte en onvoldoende bedryfsbesteding op navorsing en ontwikkeling (R&D). In die vierde stap is Porter se mededingendheidsteorie (1990; 1998) toegepas om bedryfsdeterminante van mededingende prestasie af te lei. Die faktore vanaf stap 3 is in die ses Porter-diamant determinante gegroepeer. Hoofkomponent-ontleding (principal component analysis (PCA)) is onderneem om verskille en konsensus in die sienings van die respondente met betrekking tot die relevansie en impak van die faktore wat vir elke determinant geïdentifiseer is, te identifiseer. Die resultate het getoon dat daar groot verskille in opinies was met betrekking tot 52 faktore en konsensus oor 20 faktore wat die bedryf se mededingende prestasie beïnvloed. Deur die opinies oor die impakte en langtermyn relevansie van die geïdentifiseerde faktore te analiseer, is twee waardeketting bondels geïdentifiseer, naamlik daardie opinies of respondente wat direk in die produksieprosesse van dadels betrokke is (bondel 1); en dié wat ondersteuningsfunksies verskaf (bondel 2). Die resultate dui aan dat hoewel daar ooreenkomste in opinies binne die waardeketting van die dadelbedryf is, is daar belangrike verskille wat bestaan en aangeteken is. Verskille, waarvan kennis geneem moet word in strategiese bedryfsbeplanning, is aangeteken met betrekking tot toegang tot hoë kwaliteit tegnologie, die verkryging van langtermyn krediet, diversifikasie in die internasionale mark, die koste van gespesialiseerde tegnologiese dienste, die effek van wetlike en politiese faktore op die bedryf se strategiese posisie, die land se beleid van swart ekonomiese bemagtiging (SEB), en gesondheidskoste-implikasies. In stap 5 is die belangrikste bevindings in stappe 3 en 4, tesame met die sienings wat tydens ’n dadelbedryfinligtingsessie bekom is, in ’n strategiese besluitnemingsmatriks ingesluit. Klem is gele op faktore waaroor die bedryf grootliks saamstem. Die doel was om bedryfsvlakvoorstelle te ontwikkel om die mededingende prestasie van die bedryf te verhoog. Hierdie matriks het gefokus op die stremmende faktore waaroor ’n groot mate van bedryfsvlak-konsensus opgeteken is, tesame met daardie aksies wat die prestasie onmiddellik sou kon verbeter. Die voorstelle wat vooruitstaan is: ’n fokus op die ontwikkeling van menslike hulpbronne en vaardighede; koste-delende aktiwiteite; openbare-private vennootskappe in die ontwikkeling van projekvlak sosio-ekonomiese beleggingspakkette, met ’n belegging in langtermyn navorsing en ontwikkeling (R&D); opgradering van uitvoerfasiliteite; plaaslike markontwikkeling en verbeterde samewerking met nasionale handelaars; vermindering van bemarkingskostes; diversifikasie van uitvoermarkte; ontwikkeling van verteenwoordigende bedryfsvlak- instellings en ’n bedryfsvlak- strategiese plan; en die meer doeltreffende mobilisering van regeringsvlak-ondersteuning om ’n omgewing te ontwikkel wat bevorderlik is vir die bedryf om suksesvol te kan kompeteer.

Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Two fruit fly species, Ceratitis capitata (Wiedemann) and C. rosa (Karsch) (Diptera: Tephritidae) are known to attack deciduous fruit in the Western Cape Province of South Africa. The relative abundance of these two pests was studied in different kinds of fruit throughout the year. To facilitate field monitoring, using the immature stages, morphological differences between larval instars of C. capitata and C. rosa were investigated. Morphological characters of the larvae, such as the spiracles (anterior and posterior), mouth hooks and oral ridges were used. Many of these characters are only suitable to distinguish between the second and third instar larvae as these structures are not yet developed in the first instar larvae. Anterior spiracles were examined in terms of the number of tubules (papillae) and size or shape of the felt chambers. The number of papillae in both species was similar in the second and third instar larvae, but differed between the larvae of the two species (8-10 for C. capitata and 10-13 for C. rosa). In both species the felt chambers of the second instar larvae were narrow and elongate whilst those of the third instar larvae were broad and short. The major difference between the mouthhooks of the two tephritids was the presence of a sub-apical tooth in the third instar larva of C. rosa, being absent in the third instar of C. capitata. For the morphometric study, both laboratory-reared and field-collected specimens were examined. Measurements of the body dimensions (length and width) and various parts of the cephalopharyngeal skeleton (CPS) (mandible base, mandible length and distance between the tip and notch) were recorded in all three instars of both C. capitata and C. rosa. The data were analysed using finite mixture analysis (FMA-N1) and Levene's test was used to test for homogeneity of variances. The results of these analyses were used to estimate the frequency distributions of the larval measurements. In some cases overlaps in distributions were evident and were resolved using the same program, finite mixture analysis (FMA-N1), based on the probability of the overlapping measurements belonging to the designated instar (i.e. the one with highest probability). Determination of growth ratios suggested an approximate conformation to Dyar's rule thereby disputing the possibility of any hidden instar. However, in most cases measurements of the field samples did not conform to Dyar's rule. For the larval instars of C. capitata and C. rosa with overlapping morphological features, the morphometric approach as a distinguishing tool was demonstrated. In the field survey, the relative abundance of C. rosa at all experimental sites was very low in both orchards and adjacent vines. This suggested that this pest was either not a threat in these sites (crops) or the monitoring procedures applied, should be revised. Trap catches indicated high levels of infestation by C. capitata on some sites and low infestation levels at others. On the site with the highest population levels, activity peaks in the orchards did not co-incide with those in the adjacent vineyards. This suggested that these vineyards could be alternative hosts for fruit fly after the fruit in the orchards have been harvested. Forced oviposition (in vitro) studies indicated that Colombard (grown in Simonsvlei) was the most suitable host for survival of C. capitata. Other wine grape cultivars such as Chardonnay were also suitable for the total larval development of C. capitata. / AFRIKAANSE OPSOMMING: Twee spesies van die vrugtevlieg, Ceratitis capitata (Wiedemann) en C. rosa (Karsch) (Diptera: Tephritidae), val sagtevrugte in die Wes Kaap Provinsie van Suid- Afrika aan. Die groot hoeveelheid van hierdie twee plae op verskillende soorte vrugte is regdeur die jaar bestudeer. Voordat enige insekplaag gemonitor kan word, is dit belangrik dat die identiteit van die besondere plaag, insluitend sy onvolwasse stadiums, bekend moet wees. In hierdie studie word die morfologiese verskille tussen die larwe stadiums van C. capitata en C. rosa ondersoek. Kenmerke soos die spirakels (voor en agter), mondhake en mondriwwe is gebruik. Baie van hierdie morfologiese kenmerke kan net gebruik word om te onderskei tussen larwes in die tweede en derde stadiums omdat hierdie strukture nog nie in die eerste stadium ontwikkel is nie. Die voorste spirakels is ondersoek in terme van die aantal tubules (papillae) en die grootte en vorm van die vilt kamers. In beide spesies is die aantal papillae dieselfde vir die tweede en derde larwe stadiums, maar daar was en verskil tussen die larwes van die twee spesies (8-10 vir C. capitata en 10-13 vir C. rosa). In altwee spesies was die viIt kamers van die twee stadium larwes sma I en verleng, terwyl dit in die derde stadium larwes breed en kort was. Die hoof verskil tussen die mondhake van die twee vrugtevliee was die aanwesigheid van die subapikale tand in die derde stadium larwe van C. rosa, terwyl dit afwesig is in die derde stadium van C. capitata. Vir die morfometriese studie is voorbeelde van laboratorium geteelde vrugtevliee, asook vilee wat in die veld gevind is, ondersoek. Die liggaamsafmetings (Iengte en breedte) is gemeet asook die skelet (mandibel basis, mandibel lengte en die afstand tussen die punt en die kerf) in al drie stadiums van C. capitata en C. rosa. Die data is ontleed deur middel van eindige mengsel analise (FMA-N1) en Levene se toets is gebruik om vir homogeniteit en variansies te toets. Die resultate van die ontleding is gebruik om die frekwensie verspreiding van die larwale metings te skat. In sommige gevalle was daar oorvleueling en dit is opgelos met die gebruik van dieselfde program FMA-N1 baseer op die moontlikheid dat die metings wat oorvleuel, aan die aangeduide stadium (d.w.s die een met die hoogste waarskynlikheid) behoort. Die vasstelling van groei ratios dui aan dat dit naasteby ooreenstem met Dyar se reel en dus die moontlikheid van 'n versteekte stadium betwis. Maar in die meeste gevalle stem die veldmonsters nie ooreen met Dyar se reel nie. Die feit dat die morfometriese benadering die verrnoe het om larwale monsters met oorvleuelende morfologiese kenmerke, beteken dat dit kwalifiseer as In instrument om tussen die larwe stadiums van C. capitata en C. rosa te onderskei. Baie min C. rosa is in vrugteboorde en in nabygelee wingerde gevind. Dit dui of dat die plaag nie 'n bedreiging vir die vrugte inhou nie, of dat die monitor prosedures hersien moet word. Lokvalle dui aan dat daar 'n hoe vlak van infestasie van C. capitata in sommige gebeide is en In lae vlak in ander. Op die plek met die hoogste bevolking van vrugtevliee het die aktiwiteit in die boorde nie ooreengestem met die aktiwiteit in die nabygelee wingerde nie. Dit dui aan dat hierdie wingerde 'n alternatiewe blyplek bied aan die vrugtevliee nadat die vrugte in die boorde geoes is. Gedwonge oviposisie studies dui aan dat C. capitata die beste kan oorleef in Colombard (gekweek te Simonsvlei). Ander wyndruif kultivars is ook geskik vir die ontwikkeling tot by die laaste larwe stadium van C. capitata.

Fresh ripe, cantaloupes were processed into juice and juice concentrate. Processing trials were conducted on fresh and frozen fruits with and without rind. The effects of maceration enzymes and fining agents on yield and quality were investigated. Compositional measurement included °Brix, pH, titratable acidity, formol values, ascorbic acid content, total carotenoids, sugar and nonvolatile acid profiles, browning indices and Hunter color parameters. Considerable ascorbic acid degradation occurred during processing. The high juice yield (80%) and low acidity suggest its potential use as an alternate sweetener source. Sensory evaluation by a trained panel showed that concentrating the juice samples from flesh and rind can remove the rind aroma and flavor characteristics. Juices obtained from flesh and from flesh and rind were not significantly different (p [less than or equal to] 0.05) except for overall intensity and fresh fruit flavor characters. Single strength juice was significantly different (p [less than or equal to] 0.05) from concentrate on most aroma and flavor characters. / Graduation date: 1991

This investigation was concerned with the reduction of waste in raw vegetables and fruits between the times of harvest and consumption. Reduction of spoilage in produce was attempted by means of chemical and. physical agents as well as a combination of both. The first phase of the work consisted of an evaluation of a number of chemical compounds with respect to their effectiveness in reducing post-harvest spoilage. The second part dealt with an evaluation of several transparent films applied to raw produce as wrappers and their effect on the keeping quality of the plant material until consumed. Finally combinations of surface disinfection and overwrapping were evaluated for effectiveness against raw produce spoilage. 1. Disinfection Approximately 26 compounds were tested as aqueous dips using 3 concentrations of each on 7 major vegetables and 2 fruits. The following types of compounds were studied. 1. Quaternary ammonium compounds (chlorides, bromides and pyridinium derivatives) 2. Chlorine liberators (organic and inorganic) 3. Phenols (simple and poly-phenols) 4. Quinones and hydroquinones 5. Salts of fatty acids 6. SO₂ liberators 7. Benzoates The chemical treatments were evaluated for each produce by comparison with untreated controls using duplicate tests with triplicate samples for each chemical and concentration. Promising treatments were found for all but one produce (strawberries). The treatments showing promise for each of Pascal celery and Emperor grapes were further tested on a larger scale uaing commercial size units of produce as test samples and long term cold storage. Three chemical treatments for each product were judged satisfactory enough to warrant further testing by means of field trials. The chemicals found most promising for celery were Onyxide, Cetab and Decco while Roccal, Dowicide C and Phygon were selected for grapes. A field test of the three above mentioned treatments for Pascal celery was completed. One thousand bunches per chemical were tested under commercial conditions of dipping and storing. An equal number of untreated bunches was also tested. Half-lots of each treatment were evaluated on each bunch for 11 subjective characteristics and standard mold and bacterial counts of each crate of celery were made after 8 and 14 weeks of storage. On the basis of a statistical analysis of the results, 0.1% Decco of pH=5 can be recommended for the reduction of general rot development in cold storage Pascal celery. Onyxide and Cetab significantly reduce the development of mold but commercial application cannot be recommended because the amount of visible stalk injury was significantly increased over that shown by corresponding untreated or Decco treated celery. 2. Prepackaging The following films were compared for their merit in prolonging the salable life of raw produce. Pliofilm 75FF, Pliofilm 75N2, Pliofilm 75P6A, Cellophane 300LSAT, Cellophane 300MSAT-86, Lumarith P-912, Dupont Acetate 100CA48, Polythene and Kodapak II-130. Wrapping techniques were also evaluated using the followng variations; Complete seals, tent-flap closures, single hole punctures, multiple punctures and windo bags. The following products were studied: celery, tomatoes, carrots, lettuce, cauliflower, chopped salad mix, spinach, strawberries, raspberries, blackberries, and boysenberries. Harvested produce was packaged both before and after the removal of field heat. Behavior of the pre-packaged products in both 33°F storage and subsequent 8O°F storage was studied. Cold storage was extended as long as 120 days while subsequent holding at room temperature varied widely from produce to produce. Observations were made at regular intervals for each product. Several hundred uniform samples were evaluated for most products using duplicates of each treatment for every observation period. Evaluation of most samples included weightloss, C0₂ (and sometimes O₂) of the container atmosphere, mold and decay development, flavor, color, odor, wilting and shriveling. The following conclusions were drawn: All films and wrapping methods affect produce quality. For each produce, treatments could be singled out which were superior to unwrapped controls. However any particular film and type of seal found to be superior for one produce was often not acceptable for another fruit or vegetable. Among the factors found to be critical for the proper choice of treatment were type of produce, produce temperature when packed, length of storage, and temperature of storage. A. Cold Storage For most products, the partially sealed, low permeability MSAT containers and the completely sealed Polythene wraps scored highst for overall product quality. These treatments prevented the accumulation of undesirable CO₂ while at the same time protecting the produce against weightloss and consequent wilting. For some produce, especially berries, wilting was not apparent even in high permeability films such as acetates. B. Warm Storage For produce with high respiration rates (spinach, and berries) only acetate films were acceptable as wraps. The partially sealed low permeability films maintained good quality in warm storage but the high humidity within the package was conducive to micro-organism activity. Thus, in many cases samples disinfected prior to packaging in those films improved the warm storage quality. Disinfection also improved the quality of tomatoes and chopped salad mix in acetate wraps. Of the high permeability films, no significant difference was found among the Dupont acetate, Lumarith and Kodapak II. The type of seal also did not affect the characteristics of these wraps. The low permeability films differed principally in the amount of CO₂, retained by the container during storage. The Pliofilms retained the highest C0₂, levels followed by LSAT and then MSAT Cellophane. The sealed polyethylene, the single puncture and tent flap MSAT wraps exhibited similarity, especially with respect to C0₂ accumulation. The multiple puncture low permeability wraps showed characteristics between acetates and the last mentioned group. Correlation between CO₂ accumulation and off-flavor formation could be determined for most products. Higher CO₂ levels were tolerated at short storage intervals without off- flavor formation by most products but the rate of change in CO₂ tolerance varied from produce to produce. Correlation between % weightioss and degree of wilting could also be expressed as a function of the pre-packaging treatments used. Storage infection was eliminated by all films independent of the type of seal used. It should be emphasized that only a study of the resuits and relationships discussed under each product can serve as a basis for future work and commercial application of the methods presented in this work. / Graduation date: 1950

No description available.

No description available.

The CLAVATA1 (CLV1), CLV2 and CORYNE (CRN) receptors egulate cell proliferation in shoot meristems through inhibition of WUSCHEL (WUS). Mutations in these receptors produce more floral organs. The prevailing model proposes that the extra organs are generated from enlarged floral meristems. Using forward and reverse genetics, I identified new alleles in clv1, clv2 and crn and found that most alleles only affect fruit organ number and not sepal, petal or stamen number. Analysis of inflorescence and floral meristems of clv1, clv2 and crn mutants revealed that most mutants do not have altered meristem size. I show that mutations in the ERECTA gene enhance the extra valve phenotype in crn mutants by increasing proliferation in floral meristems. Further data indicate that all mutants tested generate extra organs during fruit development and that CLV1, CLV2 and CRN expression in developing fruit overlaps with regions of increased cell division and extra organs formation. In addition, I provide evidence that CLV1 regulates the transcription factor SHOOTMERISTEMSLESS (STM) in these same regions, as mutations in STM suppress the fruit development phenotype in clv1 mutants.Analysis of the relationship between CLV pathway receptors in meristems and fruit revealed that during fruit development, all three are required to regulate fruit organ number. In meristems, I find that CLV1 appears to play a predominant role, based on evidence that the CLV1 homolog BARELY ANY MERISTEM1 (BAM1) compensates for the absence of CLV1 in the meristem but not in fruit. The fact that BAM1 does not interact genetically with CLV2 or CRN in meristems, further supports the hypothesis that BAM1/CLV1 receptor complexes play key roles in meristems. My analyses suggest that CLV3 acts specifically in the meristem pathway, and not in fruit. Also, I provide genetic data for a CLV3-related CLE gene as a ligand for the fruit-specific pathway. The work presented here provides evidence that a CLV/CRN-STM pathway acts in fruit to restrict cell division and consequently organ number via a mechanism analogous to the CLV/CRN-WUS pathway in shoot meristems, supporting the hypothesis that plants use conserved CLE/Receptor-like kinase/Homeodomain signaling module to maintain meristematic regions throughout the plant.

No description available.

No description available.

No description available.