Browsing Department of Horticulture by browse.metadata.advisor "Brink, Casper"
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- ItemInvestigating sustainable approaches to late maturity and fungal infection of organic ‘Medjool’ date palm (Phoenix dactylifera L.) fruit in the Western Cape, South Africa(Stellenbosch : Stellenbosch University, 2023-03) Peddie, Rude Jo-Anne; Lotze, Elmi; Brink, Casper; Stellenbosch University. Faculty of Agrisciences. Dept. of Horticulture.ENGLISH ABSTRACT: The commercial production of date palm in South Africa was established approximately 50 years ago in the Northern Cape with the largest orchard stretching over 100 hectares. The province has a hot and dry climate, similar to the regions of the Middle East and North Africa where date palms are traditionally produced. These conditions result in little to no issues regarding the growth and development of the fruit, the presence of pests and/or diseases during its cultivation. Date palm cultivation has since spread to climatically suitable regions in the Western Cape, which is one of the richest fruit-growing regions in the country. However, on one of the farms (approximately 30 hectares in the Hermon region), irregular ripening and high incidences of microbial spoilage were observed soon after cropping. Since the specific farm employs organic agriculture, a sustainable approach is required to address these two challenges to enable marketing of the crop. The aim of this study was to investigate the application of preharvest fruit bunch bagging as an environmentally sustainable approach to the acceleration of date fruit ripening, as well as the control of fungal infections in an organic date orchard in the Western Cape. During the 2022 season on the Kleinplasie organic date orchard near Hermon in the Western Cape, ‘Medjool’ date palm trees underwent three different non-perforated bagging treatments (no bag, blue low-density polyethylene bag, white high-density polyethylene abg) at two different phenologically important times (Khalal at 17 February 2022, Khimri at 31 March 2022) during the fruit ripening period. Preharvest analyses found that the technique, particularly the blue low-density polyethylene bags implemented later in the fruit ripening process, significantly increased fruit weight, size, and improved fruit colour at harvest. However, the microbial load was found to significantly increase at harvest, leading to higher rates of fungal infection, when compared to the other bagged treatments (p = 0.034). Postharvest analyses concluded that bunch bagging, particularly blue low-density polyethylene bags implemented earlier in the fruit ripening process, could have a positive effect on ripening of fruit under the appropriate storage conditions, and the organoleptic properties of the fruit was significantly different between treatments. According to the results of the study, it was recommended that implementing a blue low-density polyethylene bag later in the ripening process at Khalal until harvest could result in the accelerated ripening of date fruit, while applying a white high density polyethylene bag applied earlier at Khimri could aid in the control of fungal infection. This is due to the colour of the bagging material acting as a filter of photosynthetically active radiation, which refers to the range of wavelengths that aid in photosynthesis.