Investigating sustainable approaches to late maturity and fungal infection of organic ‘Medjool’ date palm (Phoenix dactylifera L.) fruit in the Western Cape, South Africa

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dc.contributor.advisorLotze, Elmien_ZA
dc.contributor.advisorBrink, Casperen_ZA
dc.contributor.authorPeddie, Rude Jo-Anneen_ZA
dc.contributor.otherStellenbosch University. Faculty of Agrisciences. Dept. of Horticulture.en_ZA
dc.date.accessioned2023-03-07T12:07:44Z
dc.date.accessioned2023-05-18T07:18:56Z
dc.date.available2023-03-07T12:07:44Z
dc.date.available2023-05-18T07:18:56Z
dc.date.issued2023-03
dc.descriptionThesis (MScAgric)--Stellenbosch University, 2023. en_ZA
dc.description.abstractENGLISH 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.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Die kommersiële produksie van dadel palmbome in Suid-Afrika was ongeveer 50 jaar terug in the Noord-Kaap gevestig, met die grootste boord wat oor 100 hektaar strek. Die provinsie het `n warm en droë klimaat wat amper identies is aan die streke van die Midde Ooste en Noord-Afrika waar die dadel palmbome tradisioneel geproduseer word. Hierdie klimaatstoestande lei na baie min of selfs geen probleme ten opsigte van die groei en ontwikkeling van die vrug, die teenwoordigheid van plae en/of siektes tydens die verbouing. Die verbouing van dadel palmbome het sedert versprei na geskikte streke in die Wes-Kaap, wat een van die rykste streke in die land in vir die groei van vrugte. Maar, een van hierdie dadel boorde (ongeveer 30 hektaar in die Hermon streek) ondervind egter probleme soos onreëlmatige rypwording and hoë gevalle van mikrobiese bederf. Omdat hierdie dadel boorde bestuur word onder organiese beginsels, is `n volhoubare benadering aan die uitdaging nodig. Die doel van hierdie studie was om voor-oes “bunch bagging” te ondersoek as `n omgewingsgewys volhoubare benadering aan die versnelling van dadel rypwording, sowel as die beheer van fungi infeksie in `n organies dadel boord in the Wes-Kaap. Gedurende die 2022 seisoen op die Kleinplasie organiese dadel boord naby Hermon in the Wes-Kaap, het ‘Medjool’ dadel palmbome drie verskillende behandelings (geen sak, blou, lae digtheid poliëtileen sak, wit, hoë digtheid poliëtileen sak) ondergaan, by twee verskillende phenologies belangrike tye (Khalal op 17 Februarie 2022, Khimri op 31 Maart 2022) tydens die rypwordingsperiode. Die voor-oes ontleding het gevind dat die metode, met spesifiek die blou, lae digtheid poliëtileen sak wat later in die vrugrypwordingsproses opgesit is, na `n betekenisvolle verhoging in vruggewig en -grootte gelei het, sowel as vrug kleur betekenisvol verbeter het. Maar die mikrobiese lading het egter `n beduidende verhoging tydens die oes tydperk vertoon, wat gelei het na hoër gevalle van swam infeksie, in vergelyking met die ander sak behandelings (p = 0.034). Die na-oes ontleding het getoon dat die metode, spesifiek die blou, lae digtheid poliëtileen sak wat vroeër in die vrugrypwordingsproses opgesit is, `n positiewe effek op die rypwording van dadels kan hê onder gepaste opberg toestande, en dat die organoleptiese eienskappe van die dadel `n betekenisvolle verskil in die behandelings vertoon het. Volgens die resultate van die studie, word dit aanbeveel dat die blou sak later, op Khalal, tot oestyd in die rypwordingsproses aangebring kan word, wat kan lei tot versnelde rypwording van dadels. Die wit sak kan vroeër, op Khimri, aangebring word, wat kan lei tot die beheer van swaminfeksie. Dit is te wyte aan die kleur van die sak at optree as filter van fotosinteties-aktiewe bestraling - die reeks golflengtes wat tot fotosintese bydra.af_ZA
dc.description.versionMastersen_ZA
dc.format.extentviii, 122 pages : illustrations (some color)en_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/127376
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subject.lcshMedjool date palm (Phoenix dactylifera L.) -- Breeding -- South Africa -- Western Capeen_ZA
dc.subject.lcshDate palm -- Diseases and pests -- Controlen_ZA
dc.subject.lcshDates (Fruit) -- Ripeningen_ZA
dc.subject.lcshDates (Fruit) -- Effect of temperature onen_ZA
dc.subject.lcshMedjool date palm -- Economic aspectsen_ZA
dc.subject.lcshFungal infectionsen_ZA
dc.subject.nameUCTDen_ZA
dc.titleInvestigating sustainable approaches to late maturity and fungal infection of organic ‘Medjool’ date palm (Phoenix dactylifera L.) fruit in the Western Cape, South Africaen_ZA
dc.typeThesisen_ZA
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