Using image analysis for assessing downy mildew severity in grapevine

Climate change critically challenges viticulture. Among other threats, extreme and increasingly frequent heatwaves cause irreversible burns on leaves and bunches. A series of observations and experiments was conducted to better understand how leaf burns originate and whether genetics or management practices can mitigate them. In 2019, a panel of 279 potted cultivars of Vitis vinifera L. grown outdoors suffered a heat peak and a genetic origin of leaf burn variability was demonstrated. To deeper explore this variability, fourteen cultivars were selected for their contrasting responses to high temperatures, and detached leaves were submitted to a controlled increase in temperature up to 50 °C in a growth chamber.

The landscape is defined by the European convention of the landscape (Florence, October 20, 2000) like part of the territory as perceived by the populations, whose character results from the action of natural and/or human factors and their interrelationships. This convention is based on the contribution cultural, ecological, environmental, social of the landscapes and aims at a reinforcement of the tools of protection and valorization in particular in the agricultural policies, of regional planning and town planning. Moreover, it encourages a step of identification and qualification of the landscapes and underlines the need for developing the sensitizing and the training of the actors concerned.

The wine industry worldwide faces increasing challenges to achieve sustainable levels of carbon emission mitigation. This project seeks to establish the feasibility of harvesting winter pruned vineyard biomass (PVB) for potential use in carbon footprint reduction, through its use as a renewable biofuel for energy production. In order to make this recommendation, technical issues such as the potential environmental impact, chemical composition and fuel suitability, and logistical challenges of harvesting biomass needs to be understood to compare with the results from similar studies. Of particular interest is the role PVB plays as a carbon source in vineyard soils and what effect annual removal might have on soil carbon sequestration. A preliminary trial was established in the Waite Campus vineyard (University of Adelaide) to test current management strategies. Vines are grown in a Eutrophic, Red Dermosol clay loam soil with well managed midrow swards. A comparison was undertaken of mid-row treatments in two 0.25 Ha blocks (Shiraz and Semillon), including annual cultivation for seed bed preparation, the deliberate exclusion of PVB (25 years) and incorporation of PVB (13 years) at an average of 3.4 and 5.5 Mg/Ha-1 for Shiraz and Semillon respectively. In both 0-10cm and 10-30cm soil core sample depths, combined soil carbon % measures in the desired range of 1.80 to 3.50, were not significantly different between treatments or cultivars and yielded an estimated 42 Mg/ha-1 of sequestered soil carbon. Other key physical and chemical measures were likewise not significantly different between treatments. Preliminary results suggest that in a temperate zone vineyard, managed such as the one used in this study, there is no long term negative impact on soil carbon sequestration through removing PVB. This implies that growers could confidently harvest PVB for use in several end fates including as a bio fuel.

Aims: The optimization of nitrogen use efficiency (NUE, i.e. uptake, assimilation and partitioning) is a solution towards the sustainable production of premium wines, while reducing fertilization and environmental impact. The influence of crop load on the accumulation of N compounds in fruits is still poorly understood. The present study assesses the impacts of bunch thinning on NUE and the consequences on the free amino N (FAN) profile in fruits.

Grapevine winter hardiness is a key factor in vineyard success in many cool climate wine regions. Winter hardiness may be governed by several factors in addition to extreme weather conditions – e.g. soil factors (texture, chemical composition, moisture, drainage), vine water status, and yield– that are unique to each site.