The suitability for viticulture at varying altitudes: a study of grapevine ripening in the Italian Alps

Un des principaux objectifs du zonage viticole est l’individuation des zones plus indiquées à la production de vins de haute qualité en relation aux cépages. Ceperrlant depuis beaucqup d’années, entre les paramètres de qualité du raisin, on n’a pas considéré les substances phénoliques par effet de l!l difficulté d’analyse en temps rapides.

The climate is the environmental factor that contributes with greater weight in the variability of the yield and the composition of the grape, therefore, it is key in the determination of the typicity of the product. Of the environmental factors, the evolution of water availability conditions, among other things, the biochemical evolution of the compounds of the grape and the type of wine to be elaborated. An integrating parameter of the hydric state of the plant is the carbon isotopic composition (δ13C). This indicator is a useful parameter to characterize the water status during the maturation period and estimate the transpiration efficiency or water use efficiency (EUA) in the vine.

Sforzato di Valtellina DOCG is a reinforced dry red wine produced in the mountain area of Valtellina alpine valley (North Italy), using ‘Nebbiolo’ grapes that undergo a withering process. This process impacts on the grape composition due to a sugar concentration and changes in secondary metabolism influencing volatile organic compounds (VOCs) and polyphenols.

Soil is a reservoir of microorganisms playing important roles in biogeochemical cycles and interacting with plants whether in the rhizosphere or in the root endosphere. The composition of the microbial communities thus impacts the plant health. Rhizodeposits (such as sugar, organic and amino acids, secondary metabolites, dead root cells …) are released by the roots and influence the communities of rhizospheric microorganisms, acting as signaling compounds or carbon sources for microbes. The composition of root exudates varies depending on several factors including genotypes. As most of the cultivated grapevines worldwide are grafted plants, the aim of this study was to explore the influence of rootstock and scion genotypes on the microbial communities of the rhizosphere and the root endosphere. The work was conducted in the GreffAdapt plot (55 rootstocks x 5 scions), in which the 275 combinations have been planted into 3 blocks designed according to the soil resistivity. Samples of roots and rhizosphere of 10 scion x rootstock combinations were first collected in May among the blocks 2 and 3. The quantities of bacteria, fungi and archaea have been assessed in the rhizosphere by quantitative PCR, and by cultivable methods for bacteria and fungi. The communities of bacteria, fungi and arbuscular mycorrhizal fungi (AMF) was analyzed by Illumina sequencing of 16S rRNA gene, ITS and 28S rRNA gene, respectively. The level of mycorrhization was also evaluated using black ink coloration of newly formed roots harvested in October. The level of bacteria, fungi and archaea was dependent on rootstock and scion genotypes. A block effect was observed, suggesting that the soil characteristics strongly influenced the microorganisms from the rhizosphere and root endosphere. High-throughput sequencing of the different target genes showed different communities of bacteria, fungi and AMF associated with the scion x rootstock combinations. Finally, all the combinations were naturally mycorrhized. The root mycorrhization intensity was influenced by the rootstock genotype, but not by the scion one. Altogether, these results suggest that both rootstock and scion genotypes influence the rhizosphere and root endophytic microbiomes. It would be interesting to analyze the biochemical composition of the rhizodeposition of these genotypes for a better understanding of the processes involved in the modulation of these microbiomes. Moreover, crossing our data with the plant agronomic characteristics could provide insights into their roles on plant fitness.

Recycled organic mulch within the row in vineyard floor management has become an interesting ecological strategy to adapt the crop to climate change consequences in semi-arid regions.
This study aimed to assess the impact of three recycled organic mulches [straw (STR), grape pruning debris (GPD), and spent mushroom compost (SMC)] and two conventional soil management practices [herbicide (HERB) and under-row tillage (TILL)] on vegetative vigour (NDVI), production (kg/plant), and physiological parameters (δ13C in grapes and leaf gas exchange during four grapevine phenology stages). Additionally, temperature and water soil parameters were collected at three soil depths. Data was collected during the 2021 and 2022 grapevine growing seasons in La Rioja, Spain.