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Table grapes from vineyard to shelf: response of crimson seedless vines and grapes to water supply and micro-climate
Thesis (PhD)--Stellenbosch University, 2025.
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867614072393957376 |
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| access_status_str | Open Access |
| author | Strydom, Janene |
| author2 | Hunter, J. J. |
| author_browse | Hunter, J. J. Strydom, Janene |
| author_facet | Hunter, J. J. Strydom, Janene |
| author_sort | Strydom, Janene |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (PhD)--Stellenbosch University, 2025. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/132414 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:46:13.197Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/132414 Table grapes from vineyard to shelf: response of crimson seedless vines and grapes to water supply and micro-climate Strydom, Janene Hunter, J. J. Raath, P. J. Stellenbosch University. Faculty of AgriSciences. Dept. of Horticultural Science. Table grapes -- South Africa -- Breede River Valley Table grapes -- Irrigation -- South Africa Table grapes -- Quality Table grapes -- Water requirements Grapes -- Climatic factors Grapes -- Effect of environment on Table grapes -- Thinning Table grapes -- Soils -- South Africa -- Breede River Valley Grapes -- Physiology Plant-water relationships Grapes -- Composition UCTD Thesis (PhD)--Stellenbosch University, 2025. Strydom, J. 2025. Table grapes from vineyard to shelf: Response of Crimson Seedless vines and grapes to water supply and micro-climate. Unpublished doctoral dissertation. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/cfda9656-5313-41c8-a6c9-0a55244eef6f ENGLISH ABSTRACT: Technology development for advancement of the SA table grape industry requires detailed knowledge of grapevine behaviour and quality variables. Table grape production depends highly on irrigation. The use of overhead plastic covering (OPC) on especially high value cultivars, is expanding in the local cultivation regions. However, its impact on plant behaviour is not sufficiently explored, especially not under different water regimes. Changes in rainfall, water supply, as well as OPC affect phenology. An open field (OF) trial, and an OPC trial were conducted on Crimson Seedless/Ramsey in the Breede River Valley. Vines were trained onto a Pergola trellis system, micro-irrigated and spaced 1.75 m x 3.0 m on a stony loam-sand soil. The layout was a randomised complete block with water regime as main factor and ripeness as split strip-plot factor. Four water treatments (replicated six times in OF and four times in OPC) included a control (100% water calculated using evapotranspiration and crop factor), and 80%, 70% and 55% less than the control. Treatments were applied from after budbreak until the end of harvest. Grapes were harvested at three ripeness levels (R₁, R₂ and R₃) plus two additional ripeness levels (R₄ and R₅), indicated by TSS. At each R, grapes were packed for storage (S₁ = 4 weeks at -0.5 plus 1 week at 7.5°C; S₂ = 8 weeks at -0.5°C plus 1 week at 7.5°C). For each sampling date, R and S, grapes were sampled and prepared for secondary compound analyses. After storage, grapes were evaluated for defects and subjected to a sensory evaluation. Growth variables, stem water potential (SWP), light intensity, photosynthetic variables, total soluble solids, total titratable acidity, berry skin colour, phenolics, volatiles, sugars and acids, amino acids, as well as hormones were determined. Reduced water supply decreased leaf area and increased light intensity. Underneath OPC, light intensity was lower compared to the OF. The effects on the physiological and vegetative growth variables were more pronounced in the OF trial. Soil water content, leaf area and photosynthetic variables underneath OPC was higher. Reduced water supply (W055) increased phenolics, phenylalanine, ABA and proline. Over two seasons, fructose and glucose were increased at some development stages, whereas there were consistent decreases in malic acid. Anthocyanins were increased by reduced water supply, but luminosity was decreased. Underneath OPC, total phenolics increased, but the total anthocyanins decreased. Volatiles such as the C₆-alcohols and norisoprenoids were changed significantly at different stages of berry development. Reduced water supply reduced berry firmness and decreased luminosity. The use of overhead plastic covering delayed colour development, but increased texture variables compared to OF. Increased ripeness levels increased storage defects only at S₂ and only in OF. Water supply correlated positively with firmness. Sweetness, sweet-sour, redness, and colour uniformity correlated positively with likeliness to purchase the grapes. The W070 and W055 treatments significantly decreased texture variables at all ripeness levels in the OF trial. In the OPC trial, the berry skin toughness and pulp firmness were increased at all ripeness levels compared to the OF trial. In this study, it was possible to obtain desirable table grape yields and grape quality while saving water. This study has shown that reduced water supply, i.e. W080 under OF conditions and W070 underneath OPC, had little or no impact on yield. Grapevines can be buffered against environmental conditions by means of OPC. Reduced water supply as well as OPC can be used to affect plant reaction and processes, and to impact positively on berry composition and thus eating quality. For table grape producers and other role players, this study provides valuable information and guidelines about the management of grape quality under current and future environmental conditions. AFRIKAANSE OPSOMMING: Tegnologie ontwikkeling vir die vooruitgang van die Suid-Afrikaanse tafeldruif industrie vereis genoegsame kennis van die gedrag van die wingerdstok en van druifkwaliteit veranderlikes. Tafeldruifproduksie steun grootliks op besproeiing. Die gebruik van oorhoofse plastiekbedekking vir die verbouing van veral hoë- prioriteit kultivars in die plaaslike produksiestreke neem toe, maar die impak van hiervan tesame met watertoediening, op plantreaksie is nog nie voldoende en sistematies ondersoek nie. Veranderinge in reënvalpatrone en watervoorsiening, asook plastiekbedekking, beïnvloed die fenologie van die wingerdstok. Om plantgedrag te ondersoek, is water (W) toegedien op onbedekte (O) (2019/2020 – 2022/2023) en op plastiekbedekte (OPB) (2021/2022 – 2022/2023) wingerdstokke. Die Crimson Seedless/Ramsey wingerdstokke is in die Breederivier Vallei geplant op ‘n sand-leem grond met 1.75 m x 3.0 m spasiëring en ‘n platdak prieëlstelsel. Die uitleg was ‘n ewekansige volledige blokontwerp met watertoediening as hooffaktor en rypheid (R) as split strook-plot faktor. Vier W toedienings het ingesluit ‘n kontrole behandeling (100% W bereken met evapotranspirasie en gewasfaktor), asook 80%, 70% en 55% minder water as die kontrole. Onder O en OPB toestande, is die behandelings onderskeidelik ses keer en vier keer herhaal. Water is in die tydperk net na bot tot net na oes toegedien. Die druiwe is geoes by drie rypheidsgrade (R1, R2 en R3) vir die O behandelings en by ‘n bykomende twee rypheidsgrade (R4 en R5) vir die OPB behandelings, soos aangedui deur totale oplosbare vastestowwe (TOV). Die druiwe is by elke R vir opberging verpak (S1 = 4 weke by -0.5°C plus 1 week by 7.5°C; S2 = 8 weke by -0.5°C plus 1 week by 7.5°C). Vir elke monsternemingstyd, R en S, is druiwe ingesamel en gevries vir die analise van sekondêre verbindings. Na opberging is die druiwe vir defekte geëvalueer en aan sensoriese evaluasie onderwerp. Veranderlikes is by verskillende korrelontwikkeling stadia gemeet en sluit in groei, stamwaterpotensiaal (SWP), ligintensiteit, fotosintese, TOV, totale titreerbare suur (TTS), dopkleur, fenole, vlugtige verbindings, suikers, organiese sure, aminosure en hormone. Ongeag die mikro-klimaatstoestande het W055 en W070 die fotosintese, transpirasie, SWP, korrelmassa, -grootte en blaaroppervlakte verminder en ligintensiteit verhoog, in vergelyking met W100. Ligintensiteit onder OPB was laer as onder O toestande. Meer betekenisvolle fisiologiese en groei reaksies is onder O as onder OPB waargeneem. Grondvoginhoud, blaaroppervlakte en fotosintese was hoër onder OPB. Fenoliese verbindings, phenylalanine, absisiensuur en prolien is verhoog deur verminderde watertoediening. Terselfdertyd is fruktose en glukose oor twee seisoene by sommige ontwikkelingstadia verhoog, terwyl appelsuur konsekwent verlaag is deur die watertoedieningsbehandelins. Verminderde watertoediening het antosianiene verhoog, maar die korrelkleur was minder helder en korrelfermheid is verlaag. Die W070 en W055 behandelings het tekstuurveranderlikes by alle R onder O toestande verlaag. Die doptaaiheid en pulpfermheid was by alle R onder OPB hoër as onder O toestande. Die OPB het totale fenole verhoog, maar totale antosianiene verlaag. Vlugtige verbindings soos die C6-alkohole en norisoprenoïede het betekenisvol verander by die sommige korrelontwikkeling stadia. Die gebruik van OPB teenoor O, het kleurontwikkeling vertraag , maar waardes vir tekstuurveranderlikes laat toeneem. Toenemende R grade het opbergingsdefekte by S2 onder O toestande laat toeneem. Soet, soet-suur balans, rooi kleur, asook uniforme kleur was voorkeur eienskappe vir verbruikers(proeërs) om druiwe te koop. In hierdie studie was dit moontlik om wenslike tafeldruif opbrengste en druifkwaliteit te verkry en terselfdertyd water te bespaar. Hierdie studie het gewys dat verminderde watertoediening van W080 in die O proef en W070 in die OPB proef, min of geen impak gehad het op opbrengste en kwaliteit nie. Oorhoofse plastiekbedekking kan dus gebruik word om wingerdstokke te buffer teen omgewingstoestande. Verminderde watertoediening sowel as OPB kan ook gebruik word om plantreaksie en prosesse te beïnvloed en om korrelsamestelling en dus eetkwaliteit positief te verander. Hierdie studie verskaf waardevolle inligting en riglyne vir tafeldruifprodusente en ander rolspelers om druifkwaliteit onder huidige en toekomstige omgewingstoestande te bestuur. Doctoral 2025-06-06T09:04:41Z 2025-06-06T09:04:41Z 2025-03 Thesis https://scholar.sun.ac.za/handle/10019.1/132414 en Stellenbosch University xxvi, 363 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Table grapes -- South Africa -- Breede River Valley Table grapes -- Irrigation -- South Africa Table grapes -- Quality Table grapes -- Water requirements Grapes -- Climatic factors Grapes -- Effect of environment on Table grapes -- Thinning Table grapes -- Soils -- South Africa -- Breede River Valley Grapes -- Physiology Plant-water relationships Grapes -- Composition UCTD Strydom, Janene Table grapes from vineyard to shelf: response of crimson seedless vines and grapes to water supply and micro-climate |
| title | Table grapes from vineyard to shelf: response of crimson seedless vines and grapes to water supply and micro-climate |
| title_full | Table grapes from vineyard to shelf: response of crimson seedless vines and grapes to water supply and micro-climate |
| title_fullStr | Table grapes from vineyard to shelf: response of crimson seedless vines and grapes to water supply and micro-climate |
| title_full_unstemmed | Table grapes from vineyard to shelf: response of crimson seedless vines and grapes to water supply and micro-climate |
| title_short | Table grapes from vineyard to shelf: response of crimson seedless vines and grapes to water supply and micro-climate |
| title_sort | table grapes from vineyard to shelf response of crimson seedless vines and grapes to water supply and micro climate |
| topic | Table grapes -- South Africa -- Breede River Valley Table grapes -- Irrigation -- South Africa Table grapes -- Quality Table grapes -- Water requirements Grapes -- Climatic factors Grapes -- Effect of environment on Table grapes -- Thinning Table grapes -- Soils -- South Africa -- Breede River Valley Grapes -- Physiology Plant-water relationships Grapes -- Composition UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/132414 |
| work_keys_str_mv | AT strydomjanene tablegrapesfromvineyardtoshelfresponseofcrimsonseedlessvinesandgrapestowatersupplyandmicroclimate |