Characterization of cv. Cabernet Sauvignon (Vitis vinifera L.): the contribution of Ecklonia maxima seaweed extract

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dc.contributor.advisorBlancquaert, Ernaen_ZA
dc.contributor.advisorSetati, Mathabatha Evodiaen_ZA
dc.contributor.authorSamuels, Liam Jayen_ZA
dc.contributor.otherStellenbosch University. Faculty of Agrisciences. Dept. of Viticulture and Oenology.en_ZA
dc.date.accessioned2022-11-24T13:09:53Z
dc.date.accessioned2023-01-23T06:52:10Z
dc.date.available2022-11-24T13:09:53Z
dc.date.issued2022-12
dc.descriptionThesis (MScAgric)--Stellenbosch University, 2022. en_ZA
dc.description.abstractENGLISH ABSTRACT: Conventionally grape cultivation makes use of chemical fertilizers and synthetic pesticides to sustain growth and ensure fruit production ultimately resulting in more resistant grapevines to pests and diseases. However, their application also imposes a negative impact on human health and the environment. Therefore, agricultural sustainability is increasingly encouraged to ensure food safety and the conservation of the environment. In this regard viticulture is urgently seeking alternative solutions to increase sustainability. Biostimulants is a novel and sustainable tool which may be a good alternative to reduce the chemical-dependency typical of conventional cultivation practices, thereby supporting eco-friendly methods to increase agricultural outputs, via fruit quality, and resistance to abiotic stress. Biostimulants is the term given to a range of products, of natural origin, known to promote vegetative and reproductive growth as well as increase tolerance against biotic and abiotic stress. Seaweed extracts, a sub-category of biostimulants, have been highlighted as one of the most promising groups of biostimulants for use in viticulture. Commercial seaweed extract products are often derived from Ascophyllum nodosum (often located on the coasts of the North Atlantic), with studies on its effects on plant physiology being very popular and well-researched. The South African species, Ecklonia maxima, and its effects on wine grapes, is however under researched. The aim of this study was to evaluate the influence of Ecklonia maxima (EM) seaweed extract on vine physiology, grape and wine quality within in the South African viticultural context on Vitis vinifera L. Cabernet Sauvignon. Foliar applications of a commercial Ecklonia maxima seaweed extract biostimulant, under the trade name Kelpak ®, were conducted before flowering, at fruit set and at véraison under two irrigation scenarios ((i) irrigated and (ii) non-irrigated). Grapevine photosynthetic capacity, chlorophyll content and water status were not impacted by the application of Ecklonia maxima. Leaf area and fruit composition were positively impacted by the treatments. The combination of EM applications and irrigation resulted in significantly higher leaf area. Furthermore, the leaf area continuously increased throughout the season which is the first study to report this finding. The latter resulted in increased concentrations of sugars, organic acids, amino acids and phenolic content in grape berries. Surprisingly, the increased concentrations of the metabolites at harvest were not reflected in the wine parameters (final alcohol content (%), wine pH and total acidity and phenolic content) made in this study. This suggests that fermentation kinetics altered the extraction of these metabolites. Our findings correspond with that of the use of Ascophylum nodosum which resulted in increased fruit quality. The study was only conducted in one season and subsequent seasons should be conducted to have a clear understanding of the photosynthetic, water use, and metabolic pathways induced when using Ecklonia maxima. Furthermore, Ecklonia maxima should be used in conjunction with conventional farming to enhance grapevine functioning and fruit quality.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Konvensionele druiweverbouing maak gebruik van chemiese kunsmis en sintetiese plaagdoders om groei te onderhou en vrugteproduksie te verseker wat uiteindelik lei tot meer weerstandbiedende wingerde teen plae en siektes. Die toepassing daarvan het egter ook 'n negatiewe impak op menslike gesondheid en die omgewing. Daarom word landbouvolhoubaarheid toenemend aangemoedig om voedselveiligheid en die bewaring van die omgewing te verseker. In hierdie verband soek wingerdbou dringend alternatiewe oplossings om volhoubaarheid te verhoog. Biostimulante is 'n nuwe en volhoubare hulpmiddel wat 'n goeie alternatief kan wees om die chemiese afhanklikheid tipies van konvensionele verbouingspraktyke te verminder, en sodoende eko-vriendelike metodes te ondersteun om landbou-uitsette te verhoog, deur vrugkwaliteit, en weerstand teen abiotiese stres. Biostimulante is die term wat gegee word aan 'n reeks produkte van natuurlike oorsprong, wat bekend is om vegetatiewe en reproduktiewe groei te bevorder, asook om verdraagsaamheid teen biotiese en abiotiese stres te verhoog. Seewierekstrakte, 'n sub-kategorie van biostimulante, is uitgelig as een van die mees belowende groepe biostimulante vir gebruik in wingerdbou. Kommersiële seewierekstrakprodukte word dikwels afkomstig van Ascophyllum nodosum (dikwels geleë aan die kus van die Noord-Atlantiese Oseaan), met studies oor die uitwerking daarvan op plantfisiologie wat baie gewild en goed nagevors is. Die Suid-Afrikaanse spesie, Ecklonia maxima, en die uitwerking daarvan op wyndruiwe, word egter onder navorsing gedoen. Die doel van hierdie studie was om die invloed van Ecklonia maxima (EM) seewierekstrak op wingerdfisiologie, druif- en wynkwaliteit binne in die Suid-Afrikaanse wingerdboukonteks op Vitis vinifera L. Cabernet Sauvignon te evalueer. Blaartoedienings van 'n kommersiële Ecklonia maxima seewierekstrak biostimulant, onder die handelsnaam Kelpak ®, is voor blom, by vrugset en op verraison uitgevoer onder twee besproeiingscenario's ((i) besproei en (ii) Nie-besproei). Wingerd fotosintetiese kapasiteit, chlorofil inhoud en water status is nie beïnvloed deur die toediening van Ecklonia maxima nie. Blaaroppervlakte en vrugtesamestelling is positief deur die behandelings beïnvloed. Die kombinasie van EM-toedienings en besproeiing het aansienlik groter blaaroppervlakte tot gevolg gehad. Verder het die blaaroppervlak voortdurend deur die seisoen toegeneem, wat die eerste studie is wat hierdie bevinding rapporteer. Laasgenoemde het gelei tot verhoogde konsentrasies van suikers, organiese sure, aminosure en fenoliese inhoud in druiwebessies. Verbasend genoeg is die verhoogde konsentrasies van die metaboliete tydens oes nie weerspieël in die wynparameters (finale alkoholinhoud (%), wyn pH en totale suur en fenoliese inhoud) wat in hierdie studie gemaak is nie. Dit dui daarop dat fermentasiekinetika die ekstraksie van hierdie metaboliete verander het. Ons bevindinge stem ooreen met dié van die gebruik van Ascophylum nodosum wat gelei het tot verhoogde vrugkwaliteit. Die studie is slegs in een seisoen uitgevoer en daaropvolgende seisoene moet uitgevoer word om 'n duidelike begrip te hê van die fotosintetiese, watergebruik en metaboliese weë wat geïnduseer word wanneer Ecklonia maxima gebruik word. Verder moet Ecklonia maxima saam met konvensionele boerdery gebruik word om wingerd se funksionering en vrugkwaliteit te verbeter.af_ZA
dc.description.versionMastersen_ZA
dc.embargo.lift2023-05-24
dc.embargo.terms2023-05-24
dc.format.extentxiii, 81 pages : illustrationsen_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/126322
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subject.lcshGrapes -- Breeding -- South Africaen_ZA
dc.subject.lcshCabernet (Wine)en_ZA
dc.subject.lcshWine and wine making -- South Africaen_ZA
dc.subject.lcshFermentationen_ZA
dc.subject.lcshGrowth (Plants) -- Regulationen_ZA
dc.subject.lcshMarine algae as fertilizeren_ZA
dc.subject.lcshEcklonia maxima -- Fertilizersen_ZA
dc.subject.lcshPhenolsen_ZA
dc.subject.lcshSeaweeden_ZA
dc.subject.nameUCTDen_ZA
dc.titleCharacterization of cv. Cabernet Sauvignon (Vitis vinifera L.): the contribution of Ecklonia maxima seaweed extracten_ZA
dc.typeThesisen_ZA
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