The marula tree has already become a very important alternative crop in South Africa with a great potential for further improvement. There are, however, no accurate records that have been reported on the fruit yield and quality of marula tree in Southern Africa. To utilise the fruit fully, to make proper selections from the wild trees and to develop new selections/cultivars, there is a need to have information on yield potential and fruit quality aspects. The overall objective was to determine the yield potential and to evaluate the fruit quality of different marula selections putting more emphasis on fruit quality parameters such as the fruit mass, size, total soluble solids (TSS), acidity and juice content. Four marula selections were identified during their peak production season(2004/2005/2006/2007) at Schoeman Boerdery (Orchard) between Marble-Hall and Groblersdal in Mpumalanga Province (South Africa). From each of the selections, namely; Pharulani, Toularula and Swarula, five trees were selected randomly and marked, while from the Wild marula only four trees were selected and marked. For the purpose of experimental design, the four selections were regarded as four treatments, and the marked trees per selection as the replicates. All selected trees were more or less the same in size and were in full production. The trees were growing in an orchard with planting distance of 9 m (interspacing) and 4.5 m (intraspacing). To determine yield potential, the number of fruit per square meter per tree was counted on pre-labelled branches on five positions around the tree canopy at three stages of fruit development. Collected data were converted to grams of fruit per square metre. Tree canopy size (CS), expressed as m2, was calculated by using the radius (r) of each canopy in the following formula: CS= (╥.r2) 4. For calculating the yield per tree, the average canopy size was multiplied by the number of fruit counted per m2. Twenty fruits from each labelled marula tree per selection were randomly selected; collected and taken to the Ecophysiology Laboratory at University of Pretoria for fruit quality traits, weight (mass), size, stone mass, peel mass, juice content, Total Soluble Solids (TSS) and Titratable acidity (TA). The yield efficiency/potential for both tree unit and hectare (ha) basis in 2006/2007 season, showed that the Swarula selection had the highest total yield as compared to other selections. Results showed that there was a positive relationship between fruit weight and size, that is, the bigger the weight, the bigger the size and the opposite. Generally, three selections, Swarula, Toularula and Pharulani had a higher fruit mass and size than “wild” marula. Pharulani had the highest seed/stone mass whereas “wild” marula had the lowest seed mass during the 2004/2005 and 2005/2006 fruiting seasons. Pharulani selection had the highest juice mass during both seasons whereas Swarula selection had the lowest juice mass. Results also showed that ‘wild’ marula had the highest TSS/TA ratio during both seasons whereas Pharulani had the lowest TSS/TA ratio. Optimal traits were therefore found in different selections and not in the same selections as envisaged. Copyright / Dissertation (MInst Agrar)--University of Pretoria, 2009. / Plant Production and Soil Science / unrestricted

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Thesis (M.Sc. (Horticulture)) -- University of Limpopo, 2022 / The purpose of this study was to assess the impact of pre-harvest bagging materials on maturity indices and post-harvest quality of cherry tomatoes. At pre-harvest, fruit were bagged with blue and transparent plastic bags of 0.075- and 0.025-mm thickness, respectively. The non-bagged fruit were considered as control treatment. The experiment was carried out in a randomized complete block design arranged in a 2 × 3 factorial arrangement with three replications. Physical quality parameters such as; colour changes (L*, a*, b*, C*, h˚, and ΔE), firmness, weight loss and size were assessed. Physico-chemical parameters such as pH, total soluble solids, and total titratable acidity were also evaluated. Bagging had a significant effect on the quality of both cherry tomato cultivars. The results showed that bagging cherry tomatoes at 1.5 cm diameter with blue and transparent plastic bags accelerated maturity. Moreover, bagging with transparent plastic bags enhanced exocarp colour, reduced weight loss, retained larger size, increased pH and TTA, with an increase in TSS when compared with blue plastic bags and control, respectively at 12 days of shelf-life. In conclusion, the findings demonstrate that pre-harvest bagging has the potential to improve maturity indices and post-harvest quality of cherry tomatoes. Therefore, pre-harvest bagging can be used as an alternative method to enhance cherry tomato fruit quality and shelf-life. / NRF

Made available in DSpace on 2014-08-20T14:32:59Z (GMT). No. of bitstreams: 1 Dissertacao_Andre_Luiz_Radunz.pdf: 2353919 bytes, checksum: 1448629eb86ad56fa1ff43413ca14de1 (MD5) Previous issue date: 2012-02-16 / In order to reach the strengthening and the development of family agriculture as well as the premise of diversification of the productive sources, there appears as an alternative the cultivation of common vineyards destined to the production of home-grown wine, juices and derivatives. Attempts were made to evaluate the existing relationships among local meteorological variables and handling practices, dry pruning and green pruning and the effects on phenological behavior, productive aspects and on the quality of the cultivated grape under the conditions of the region of Pelotas/RS. For this purpose, a family based agricultural property was selected located in the 8TH district of Pelotas/RS, in which the experiment was carried out and where the experimental delineation was composed for a (2 x 2 x 2) factorial, these being: (Bordô and BRS Violeta) cultivar, period of dry pruning (normal and late) and green pruning (with and without defoliation). Evaluations were carried out during harvest of total soluble solids, of the mass of clusters, of the number of clusters of grapes per cluster and production per plant. Moreover, global solar radiation was measured in each treatment, reflected by the canopy and available at the level of clusters as well as the daily temperature of the vineyards, Results demonstrate that the period of dry pruning affected the production and the accumulation of total soluble solids and on cv. BRS Violeta, only the total soluble solids. When relating the period of dry pruning with defoliation over total soluble solids, these differed only in the treatment with defoliation, being greater in the late period. Defoliation carried out on cv. Bordô reduced the number of grapes per cluster. However, it increased weight of the clusters and presented no differences for the BRS Violeta . Defoliation associated with the normal period increased the production per plant and the number of clusters on Bordô and presented no differences on the cv. BRS Violeta. The results demonstration that the average albedo presented short variation 0,287, 0,280, 0,295, 0,297, 0,304 e 0,287 for the respectively treatments BNC, BTC, BTS, VNC, VTC and VTS, being B e V refer of the cultivars Bordô and BRS Violeta, N and T of the dry pruning and C and S with and without. The cv. BRS Violeta presented greater availability of solar radiation at the level of clusters and higher rate of total soluble solids during harvest when compared with cv. Bordô. The period of dry pruning did not represent difference in the quantity of solar radiation available at the level of clusters but the defoliation propitiated increase in incident radiation a the level of clusters for cv. Bordô and BRS Violeta. Solar radiation available at the level of clusters showed itself related to the accumulation of total soluble solids, being greater when the available radiation was greater on cv. Bordô. / A fim de atingir o fortalecimento e o desenvolvimento da agricultura familiar e a premissa da diversificação da matriz produtiva das unidades familiares, tem-se como alternativa o cultivo de videiras comuns destinadas à produção de vinhos coloniais, sucos e derivados. Buscou-se avaliar as relações existentes entre variáveis meteorológicas locais e as práticas de manejo, poda seca e poda verde, e seus efeitos no comportamento fenológico, nos aspectos produtivos e na qualidade da uva cultivada nas condições da região de Pelotas/RS. Para tanto, foi selecionada uma propriedade agrícola familiar localizada no 8º Distrito de Pelotas/RS, na qual foi realizado o experimento, sendo o delineamento experimental composto por um fatorial (2 x 2 x 2), sendo estes: cultivar (Bordô e BRS Violeta); época de poda seca (normal e tardia); e poda verde (com e sem desfolha). Foram realizadas durante a colheita avaliações de sólidos solúveis totais, da massa dos cachos, do número de cachos e de bagas por cacho e da produção por planta. Ainda em cada tratamento foi medida a radiação solar global, refletida pelo dossel e disponível ao nível dos cachos e também a temperatura diária no vinhedo. Os resultados demonstram que a época da poda seca exerceu influência sobre o comportamento fenológico, sobre a necessidade térmica e o número de dias para completar o ciclo. Na cv. Bordô a época da poda seca afetou a produção e o acúmulo de sólidos solúveis totais (SST) e na cv. BRS Violeta apenas o SST. Ao relacionar a época da poda seca com a desfolha, sobre os sólidos solúveis totais, estes diferiram apenas no tratamento com desfolha, sendo maior na época tardia. A desfolha realizada na cultivar Bordô reduziu o número de bagas por cacho, entretanto aumentou o peso de cachos e sem diferenças para a BRS Violeta . A desfolha associada à época normal aumentou a produção por planta e o número de cachos na Bordô e sem diferenças para a cultivar BRS Violeta. O albedo médio para os tratamentos BNC, BTC, BTS, VNC, VTC e VTS foi respectivamente, 0,287, 0,280, 0,295, 0,297, 0,304 e 0,287. A cultivar BRS Violeta apresentou maior disponibilidade de radiação solar ao nível dos cachos e maior teor de sólidos solúveis totais na colheita quando comparada a cultivar Bordô. A época de poda seca não representou diferença na quantidade de radiação solar disponível ao nível dos cachos, já a realização da desfolha propiciou aumento na radiação que incide ao nível dos cachos para a cv. Bordô. A radiação solar disponível ao nível dos cachos mostrou-se relacionada ao acúmulo de sólidos solúveis totais, sendo maior este acúmulo quando a radiação disponível foi maior na cultivar Bordô.

Total soluble solids (TSS) is a reliable indicator of melon eating quality, with a minimum standard of 10% recommended. The state of Australian melon production with respect to this quality criterion was considered within seasons, between growing districts and over seasons. It was concluded that improvement in agronomic practice and varietal selection is required to produce sweeter melons. The scientific literature addressing melon physiology and agronomy was summarised, as a background to the work that is required to improve melon production practices in Australia. The effect of source sink manipulation was assessed for commercially grown and glasshouse grown melon plants. The timing of fruit thinning, pollination scheduling, the application of a growth inhibitor and source biomass removal were assessed in relation to fruit growth and sugar accumulation. Results are interpreted against a model in which fruit rapidly increase in weight until about two weeks before harvest, with sugar accumulation continuing as fruit growth ceases. Thus treatment response is very dependant on timing of application. For example, fruit thinning at 25 days before harvest resulted in further fruit set and increased fruit weight but did not impact on fruit TSS (at 9.8%, control 9.3%), while thinning at 5 days before harvest resulted in a significant (Pless than 0.05) increase in fruit TSS (to 10.8%, control 9.3%) and no increase in fruit weight or number. A cost/ benefit analysis is presented, allowing an estimation of the increase in sale price required to sustain the implementation of fruit thinning. The effect of irrigation scheduling was also considered with respect to increasing melon yield and quality. To date, recommended practice has been to cause an irrigation deficit close to fruit harvest, with the intent of 'drying out' or 'stressing' the plant, to 'bring on' maturity and increase sugar accumulation. Irrigation trials showed that keeping plants stress-free close to harvest and during harvest, facilitated the production of sweeter fruit. The maintenance of a TSS grade standard using either batch based (destructive) sampling or (non-invasive) grading of individual fruit is discussed. On-line grading of individual fruit is possible using near infrared spectroscopy (NIR), but the applicability of the technique to melons has received little published attention. Tissue sampling strategy was optimised, in relation to the optical geometry used (in commercial operation in Australia), both in terms of the diameter and depth of sampled tissue. NIR calibration model performance was superior when based on the TSS of outer, rather than inner mesocarp tissue. However the linear relationship between outer and middle tissue TSS was strong (r2 = 0.8) in immature fruit, though less related in maturing fruit (r2 = 0.5). The effect of fruit storage (maturation/senescence) on calibration model performance was assessed. There was a negligible effect of fruit cold storage on calibration performance. Currently, the agronomist lacks a cost-effective tool to rapidly assess fruit TSS in the field. Design parameters for such a tool were established, and several optical front ends compared for rapid, though invasive, analysis. Further, for visualisation of the spatial distribution of tissue TSS within a melon fruit, a two-dimensional, or hyper-spectral NIR imaging system based on a low cost 8-bit charge coupled device (CCD) camera and filter arrangement, was designed and characterised.