Technical Yearbook 2023

TABLE 2. Grape composition at harvest. Treatment with LalVigne ProHydro™ enables good acidity to be maintained and sugar to be accumulated in the samples subjected to water and thermal stress, as well as allowing complete phenolic maturation. Different letters indicate statistically significant differences between treatments (p < 0.05).

Sugars (°Brix) 21.40 b 21.77 b 21.45 b 24.07 a

Titratable acidity (g/L)

Yield (kg/vine)

Sangiovese

pH

Irrigated control

5.80 c 7.12 a 6.40 b 6.70 ab

3.33 3.21 3.20 3.28

0.93 b 0.96 b 0.84 c 1.09 a

Irrigated ProHydro™ Control water stress ProHydro™ water stress

FIGURE 4 . Photochemical efficiency of the photosynthetic system (A) and chlorophyll content in SPAD units (B) of LalVigne ProHydro™ treated and control plants at times indicated by the arrows at a dose of 1 kg/ha in plants subjected to a period of pre-veraison water stress. The photochemical efficiency is calculated as the ratio between Fv fluorescence (difference between the minimum and maximum fluorescence) and Fm (maximum fluorescence); values below 0.65 indicate that the photosynthesis system suffered permanent damage. *: indicates significant differences between control and treated plants.

In this study, carried out in a semi-controlled environment in potted Sangiovese vines, it was shown that foliar treatments carried out between fruit set and veraison with LalVigne ProHydro™ can help to avoid production losses linked to water stress and, at the same time, maintain the accumulation of sugars and phenolic compounds. These effects are linked to the enhanced physiological performance of the treated plants when stressful conditions arise. The

treated plants do not suffer permanent damage to the photosynthetic system, allowing complete functional integrity of the foliage to be retained, with a greater allocation of photosynthates until harvest. These data confirm that the maximum effectiveness of LalVigne ProHydro™ is obtained with preventive treatments undertaken in the period in which water stress can severely compromise yield (fruit set veraison period). 

Reference https://www.wineland.co.za/management-of-vine-water-stress/

For more information, please contact Piet Loubser at ploubser@lallemand.com.

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TECHNICAL YEARBOOK 2023