Theses and Dissertations

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Browsing Theses and Dissertations by Author "Gwata, E."

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    Performance of selected different types of stone fruits in a summer rainfall area, South Africa
    (2013-12-10) Ramphinwa, Maanea Lonia; Mchau, G.R.A.; Gwata, E.
    Temperate fruit trees cultivated in areas of mild winter conditions result in a number of insufficient chilling symptoms. Such insufficient symptoms are described in general as the absence of bud break, delayed foliation, reduced fruit set as well as reduced fruit quality. Therefore, after bud break, fruit trees show insufficient symptoms such as paralysis of the shoot growth, development of small leaves, low rate of effective fructification, and reduction of the flowering-maturity circle and development of small flat fruits. Adequate information of chilling requirements, dates of dormancy breaking and appropriate chemical agents, which should be applied to meet chilling requirement is required for successful production of stone fruit. South African (SA) deciduous fruit has been exported successfully (primarily to the UK and Europe) since 1892 and SA is currently a major Southern Hemisphere supplier of fresh fruit between the months of October and August (Huysane, 1996). In order to remain competitive, there is a need to expand the production of stone fruits from traditional Western Cape to a summer rainfall area in Limpopo Province. The broad objectives of the study was to evaluate some quantitative and qualitative performance traits of different types of stone fruits in a summer rainfall area in Limpopo Province. The project was initiated in 2007 by Agricultural Research Council through the collaboration of Agricultural Research Council (ARC) Infruitec-Nietvoorbij (Stellenbosch) Western Cape and University of Venda in Limpopo Province. This was a continuous assessment about the performance of selected stone fruit cultivars in a summer rainfall area, South Africa. Growth data was sampled on each tree. Circumference measurement of the graft union after the growing season was measured using a soft pliable measuring tape in order to get an indication of the growth rate. This was done annually during winter period. The experimental design was a completely randomized design (CRD) with six trees (experimental units) randomly selected for each of the four species ('Charisma', 'Summersun', 'Pioneer 'and 'Mayglo'). Analysis of variance was performed on all variables accessed using GLM (General Linear Models) Procedure of SAS statistical software version 9.2 (SAS Institute Inc., Cary, NC, USA, 2003). Shapiro-Wilk test was performed to test for normality (Shapiro, 1965). There was significant different on diameter of stems, scion height and production of secondary branches of trees on the four different stone fruit trees studied. 'Mayglo' and 'Summersun' trees had high buds production, blooming, and fruit-set than 'Charisma' and 'Pioneer' trees in year 2009. All trees had a very good bud production and blooming, but only 'Mayglo' and 'Summersun' had a good fruit set compared 'Charisma' and 'Pioneer' in year 2010.
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    Soil compaction and texture effect on yield, vegetative growth parameters and quality of potato tubers (Solanum tuberosum L.) in selected sites in Limpopo Province.
    (2020-06-24) Mufandilani, Mvusuluso; Wakindiki, I.; Gwata, E.
    Compaction limits soil productivity especially plant growth. However, the effect of compaction in various South African soils on potato (Solanum tuberosum L.) tubers is not well understood. The purpose of this study was to investigate the effect of compaction in various soils on the number of stems, plant germination, number of tubers, plant vigour, plant height, biomass, size, shape, dry matter, fresh weight, specific gravity of potato tubers. It was hypothesized that soil compaction affects growth and quality of potato tubers. Soil samples were collected from four different potato farms and subjected to different levels of compaction, simulating field conditions. The experiment was conducted in a complete randomized design with a split plot treatment structure with three replications. Treatments were compacted, non-compacted soil and four different textures (loamy sand, sandy loam, clay and fine sandy). Sifra and Fandago potato cultivars were used to test response to the treatments. Potato tubers were harvested after 120 days. Analysis of variance was conducted using Minitab software version 17. The comparison of means was done using the Tukey method. It was generally found that size of tuber was decreased (>40%) by soil compaction for both cultivars. The shortest tuber size (46.1 mm) was obtained in the fine sandy loam soil. The clay soil produced the highest (21) specific gravity. Soil compaction slightly deformed some potato shapes but were not detected statistically. Fresh weight of tubers was decreased by 32% between the noncompacted and compacted soil. The highest plant vigour (3.4) was observed for loamy sand soil. Similarly, the tallest crop (38.2 cm) were observed in the sandy loam soil. Crop height was decreased by 38% at the compacted soil. It was apparent that Loamy sand and sandy loam soil seem to be suitable soil texture for potato production. Soil compaction had a negative impact, significantly producing small tubers, low yield, low specific gravity, crop height and number of potato tubers.