Thesis (MscAgric (Viticulture and Oenology))--Stellenbosch University, 2008. / The effect of various irrigation strategies on grapevine water relations during the
berry ripening period was investigated in a Shiraz/Richter 99 vineyard. Comparisons
between different irrigation strategies (full/seasonal, véraison+post véraison, post
véraison and no irrigation) were made.
During the day, the seasonally irrigated vines experienced less water stress than the
deficit treatments. Non-irrigated vines seemed to maintain higher diurnal leaf water
potentials. Lower leaf water potentials indicated lower water contents in the
vegetative and reproductive tissue. Full irrigation seemed to stimulate primary shoot
length. Longer water deficit induced earlier and more complete shoot maturation
(reserve accumulation). Re-distribution of leaf area on the shoot may occur when
vines are subjected to water deficit. Extended water deficit seemed to induce earlier and restricted water loss from vegetative tissue. The water relations were reflected in the berry size. Irrigation during ripening seemed to induce a continuation of berry water loss. Transpiration losses were apparently much higher in fully irrigated vines
whereas stomatal control efficiently maintained water relations in non-irrigated vines. Water deficit seemed to have enhanced the soluble solid accumulation. Irrigation
treatments did not seem to affect the titratable acid and pH. The post véraison
irrigation in particular seemed to favour a wide window for harvesting. Irrigation at
post véraison and especially véraison+post veraison seemed to have a greater effect
on the synthesis and extraction of phenolics, anthocyanins and tannins in the berry skins. Different irrigation strategies may affect grapes in such a way that different wine styles are obtained.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/2328 |
| Date | 03 1900 |
| Creators | Ellis, Warren |
| Contributors | Hunter, J. J., Goussard, P. G., Deloire, A., Stellenbosch University. Faculty of AgriSciences. Dept. of Viticulture and Oenology. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 1887556 bytes, application/pdf |
| Rights | Stellenbosch University |
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