Nitrogen isotope ratio (δ15N) as a tool to trace the major nitrogen source in vineyards

Grapevine cultivars are vegetatively propagated to maintain their varietal attributes. However, spontaneous somatic variation emerges during prolonged periods of vegetative growth, providing an opportunity for the natural improvement of traditional grapevine cultivars. Notably, reduction in bunch compactness is a favorable trait in viticulture, offering advantages such as decreased susceptibility to bunch fungal diseases, and a more uniform ripening of berries. To unravel the genetic and developmental mechanisms behind bunch compactness variation, we examined a somatic variant of Tempranillo Tinto cultivar with loose bunches. We found that the mutant clone exhibits a ~50% reduction in pollen viability compared to typical Tempranillo clones.

Long-term use of copper fungicides causes increased accumulation of total copper in the surface layer of vineyard soils. Many of authors has researched the anthropogenic influx of copper in such soils, which can result in environmental risks.

Grapevine yield has been historically overlooked, assuming a strong trade-off between grape yield and wine quality. At present, menaced by climate change, many vineyards in Southern France are far from the quality label threshold, becoming grapevine yield-gaps a major subject of concern. Although yield-gaps are well studied in arable crops, we know very little about grapevine yield-gaps. In the present study, we analysed the environmental component of grapevine yield-gaps linked to climate and soil resources in the Languedoc Roussillon. We used SAFRAN data and IGP Pays d’Oc wine yields from 2010 to 2018. We selected climate and soil indicators proving to have a significant effect on average wine yield-gaps at the municipality scale. The most significant factors of grapevine yield were the Soil Available Water Capacity; followed by the Huglin Index and the Climatic Dryness Index. The Days of Frost; the Soil pH; and the Very Hot Days were also significant. Then, we clustered geographical zones presenting similar indicators, facilitating the identification of resources yield-gaps. We discussed the number of zones with the experts of IGP Pays d’Oc label, obtaining 7 zones with similar limitations for grapevine yield. Finally, we analysed the main resources causing yield-gaps and the grapevine varieties planted on each zone. Mapping grapevine resource yield-gaps are the first stage for understanding grapevine yield-gaps at the regional scale.

In the context of sustainable viticulture, modern and efficient techniques to determine water status are required to optimize irrigation practices. Proximal techniques such as thermography and spectroscopy have shown promising results. When these techniques are incorporated into mobile systems is possible to evaluate the water status on-the-go, offering the possibility to generate variability maps. However, in most cases, complex protocols of data acquisition and analysis are required. Also, the inherent physiological behaviour of the plants under certain water stress conditions needs to be considered. Therefore, the aim of this study was to evaluate the effect of scion-rootstock combinations on the performance of a predefined plant-based method based on proximal near-infrared (NIR) spectroscopy.

The under-way zoning works of the Emilia viticulture have pointed out a huge variability of the features of the soils, which belong to this area.