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The effect of plant water potential-based deficit irrigation on physiological reproductive responses of grapevines (cv. Shiraz) in different climatic regions.
Thesis (MScAgric)--Stellenbosch University, 2023.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2023
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| _version_ | 1867613986959130624 |
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| access_status_str | Open Access |
| author | Visser, John-Murray |
| author2 | Lategan, Eugene Lourens |
| author_browse | Lategan, Eugene Lourens Visser, John-Murray |
| author_facet | Lategan, Eugene Lourens Visser, John-Murray |
| author_sort | Visser, John-Murray |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScAgric)--Stellenbosch University, 2023. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/127353 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:44:52.037Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2023 |
| publishDateRange | 2023 |
| publishDateSort | 2023 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/127353 The effect of plant water potential-based deficit irrigation on physiological reproductive responses of grapevines (cv. Shiraz) in different climatic regions. Visser, John-Murray Lategan, Eugene Lourens Hoffman, Eduard Josias Van Zyl, Jan Louis Stellenbosch University. Faculty of Agrisciences. Dept. of Soil Science. Wine grapes, midday stem water potential, water use efficiency, yield Grapevines (cv. Shiraz) -- Physiological effect Deficit irrigation Grapes -- Climatic factors -- South Africa Grapes -- Growth -- Field experiments Plant-water relationships Plants -- Effect of water levels on Soils -- Effect of water levels on UCTD Thesis (MScAgric)--Stellenbosch University, 2023. ENGLISH ABSTRACT: This thesis explores the effects of three midday stem water potential (midday ψS) thresholds on the physiological and reproductive responses of grapevines cv. Shiraz. Threshold treatments were applied, between pea berry stage and harvesting during three growing seasons i.e. from 2019/20 until 2021/22. The experiment was carried out in three main wine grape growing regions of South Africa namely, Olifants River Valley (Klawer), Breedekloof Valley (Slanghoek) and Coastal region (Stellenbosch). The following midday ψS thresholds were applied: -1.1 MPa (T1); -1.5 MPa (T2) and - 1.8 MPa (T3). Over the three seasons and in all regions, T3 produced bunches with lowest mass, compared to that of T1. Improvements in overall grape quality also occurred due to significant reductions in water applications in all three regions. The Klawer region had a saving in irrigation water of 38% for T2 and 55% for T3 compared to T1 while these savings were 64% and 81% in Slanghoek a similar trend occurred in the Stellenbosch region with a reduction of 39% for T2 and 89% for T3 compared to T1. The study concluded that there is a correlation of midday ψS with yield. The research can greatly help the wine industry with water saving and improved wine quality through the use of midday ψS as an aid in irrigation scheduling. AFRIKAANSE OPSOMMING: Hierdie tesis ondersoek die uitwerking van drie middel van die dag stamwaterpotensiaal (middag ψS) drempelwaardes op die fisiologiese en reproduktiewe reaksies van wingerde cv. Shiraz. Die drempelwaardes (wat behandelings voorstel) is toegepas, tussen ertjie stadium en oes gedurende drie groeiseisoene, dit wil sê vanaf 2019/20 tot 2021/22. Die eksperiment is in drie hoof wyndruifverbouingstreke van Suid-Afrika uitgevoer, naamlik Olifants Rivier Vallei (Klawer), Breedekloof Vallei (Slanghoek) en die Kusstreek (Stellenbosch). Die volgende middag ψS drempelwaardes is toegepas: -1.1 MPa (T1); -1,5 MPa (T2) en - 1,8 MPa (T3). Oor die drie seisoene en in alle streke het T3 trosse geproduseer met die laagste massa , invergelyking met dié van T1. Verbeterings in algehele druifkwaliteit het ook plaasgevind as gevolg van die aansienlike vermindering in watertoedienings in al drie streke. Die Klawer-streek het 'n besparing in besproeiingswater van 38% vir T2 en 55% vir T3 in vergelyking met T1 gehad terwyl hierdie besparings 64% en 81% in Slanghoek was. 'n Soortgelyke tendens het in die Stellenbosch-streek voorgekom met 'n vermindering van 39% vir T2 en 89% vir T3 in vergelyking met T1. Die studie het tot die gevolgtrekking gekom dat daar 'n korrelasie van middag ψS met opbrengs is. Die navorsing kan die wynbedryf baie help met waterbesparing en verbeterde wyngehalte deur die gebruik van middag ψS as hulpmiddel in besproeiingskedulering. Masters 2023-03-06T13:41:11Z 2023-05-18T07:17:43Z 2023-03-06T13:41:11Z 2023-05-18T07:17:43Z 2023-03 Thesis http://hdl.handle.net/10019.1/127353 en_ZA Stellenbosch University 97 pages : illustrations (some color) application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Wine grapes, midday stem water potential, water use efficiency, yield Grapevines (cv. Shiraz) -- Physiological effect Deficit irrigation Grapes -- Climatic factors -- South Africa Grapes -- Growth -- Field experiments Plant-water relationships Plants -- Effect of water levels on Soils -- Effect of water levels on UCTD Visser, John-Murray The effect of plant water potential-based deficit irrigation on physiological reproductive responses of grapevines (cv. Shiraz) in different climatic regions. |
| title | The effect of plant water potential-based deficit irrigation on physiological reproductive responses of grapevines (cv. Shiraz) in different climatic regions. |
| title_full | The effect of plant water potential-based deficit irrigation on physiological reproductive responses of grapevines (cv. Shiraz) in different climatic regions. |
| title_fullStr | The effect of plant water potential-based deficit irrigation on physiological reproductive responses of grapevines (cv. Shiraz) in different climatic regions. |
| title_full_unstemmed | The effect of plant water potential-based deficit irrigation on physiological reproductive responses of grapevines (cv. Shiraz) in different climatic regions. |
| title_short | The effect of plant water potential-based deficit irrigation on physiological reproductive responses of grapevines (cv. Shiraz) in different climatic regions. |
| title_sort | effect of plant water potential based deficit irrigation on physiological reproductive responses of grapevines cv shiraz in different climatic regions |
| topic | Wine grapes, midday stem water potential, water use efficiency, yield Grapevines (cv. Shiraz) -- Physiological effect Deficit irrigation Grapes -- Climatic factors -- South Africa Grapes -- Growth -- Field experiments Plant-water relationships Plants -- Effect of water levels on Soils -- Effect of water levels on UCTD |
| url | http://hdl.handle.net/10019.1/127353 |
| work_keys_str_mv | AT visserjohnmurray theeffectofplantwaterpotentialbaseddeficitirrigationonphysiologicalreproductiveresponsesofgrapevinescvshirazindifferentclimaticregions AT visserjohnmurray effectofplantwaterpotentialbaseddeficitirrigationonphysiologicalreproductiveresponsesofgrapevinescvshirazindifferentclimaticregions |