Articles
Effect of plant water potential based deficit irrigation on physiological and reproductive responses of grapevine (‘Shiraz’) in three different climatic regions
Article number
1409_58
Pages
459 – 466
Language
English
Abstract
This article explores the effects of three midday stem water potential (midday 
S) thresholds on the physiological and reproductive responses of ‘Shiraz’ grapevines.
Threshold treatments were applied, between pea berry stage and harvesting during three growing seasons 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 middayS thresholds were applied: -1.5 MPa (T2), -1.8 MPa (T3) and T1 that corresponded to the irrigation carried out by the farmer.
Over the three seasons and in all regions, T3 produced bunches with the lowest mass.
The Klawer region had a saving in irrigation water of 36% for T2 and 52% for T3 compared to T1 while these savings were 63 and 78% in Slanghoek.
A similar trend occurred in the Stellenbosch region with a reduction of 39% for T2 and 86% for T3 compared to T1. The study concluded that there is a correlation of middayS with yield.
The research can greatly help the wine industry with water saving through the use of middayS as an aid in irrigation scheduling.
S) thresholds on the physiological and reproductive responses of ‘Shiraz’ grapevines.Threshold treatments were applied, between pea berry stage and harvesting during three growing seasons 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
S thresholds were applied: -1.5 MPa (T2), -1.8 MPa (T3) and T1 that corresponded to the irrigation carried out by the farmer.Over the three seasons and in all regions, T3 produced bunches with the lowest mass.
The Klawer region had a saving in irrigation water of 36% for T2 and 52% for T3 compared to T1 while these savings were 63 and 78% in Slanghoek.
A similar trend occurred in the Stellenbosch region with a reduction of 39% for T2 and 86% for T3 compared to T1. The study concluded that there is a correlation of midday
S with yield.The research can greatly help the wine industry with water saving through the use of midday
S as an aid in irrigation scheduling.
Authors
J. Visser, E.L. Lategan, J.L. Van Zyl, J.E. Hoffman
Keywords
midday stem water potential, wine grapes, yield
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