The SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1) is a key floral activator that coordinates external and internal stimuli to ensure timely flowering. During early stages of flower formation, SOC1 represses floral organ identity genes such as AGAMOUS (AG) to prevent premature organ differentiation. In addition to floral organ specification, AG has been shown to regulate fleshy fruit expansion and ripening and, as such, is an important contributor to fruit quality traits. Currently, little is known about the function and gene regulatory network of the grapevine homologs VviSOC1a and VviAG1. As such, the aim of this study was to functionally characterise both genes by overexpressing them in tomato and performing phenotypic and gene expression studies.

In the last decades, climate change required already adaptation of vineyard management. Increase in temperature and unexpected weather events cause changes in all phenological stages requiring new management tools. For example, defoliation can be a useful tool to reduce the sugar content in the berries creating differences in the wine profiles. In a ten-year field experiment using Riesling (Vitis vinifera L, planted 1986, Geisenheim, Germany), various mechanical defoliation strategies and different intensities were trialed until 2016 before the vineyard was uprooted. Wood was sampled from the plant compartments root, trunk, cordon and shoot for analyses of physicochemical properties (e.g. lignin and element content, pH, diameter), nonstructural carbohydrates and the microbial communities. The aim of the study was to investigate the influence of reduced canopy leaf area on the sink-source allocation into different compartments and potential changes of the fungal and prokaryotic wood-inhabiting community using a metabarcoding approach. Severe summer pruning (SSP) of the canopy and mechanical defoliation (MDC) above the bunch zone decreased the leaf area by 50% compared to control (C). SSP reduced the photosynthetic capacity, which resulted in an altered source-sink allocation and carbohydrate storage. With lower leaf area, less carbohydrates are allocated. This for example resulted in a decreased trunk diameter. Further, it affected the composition of the grapevine wood microbiota. SSP and MDC management changed significantly the prokaryotic community composition in wood of the root samples, but had no effect in other compartments. In general, this study found strong compartment and less management effects of the microbial community composition and associated physicochemical properties. The highest microbial diversities were identified in the wood of the trunk, and several species were recorded the first time in grapevine.

Fungus resistant grape varieties (FRGV or PIWI) offer many benefits such as less pesticide use or premium prices for enhanced sustainability. Still, winemakers are concerned about inferior wine quality. This study evaluates how European wine consumers assess wines made from new FRGVs in comparison to traditional V. vinifera varieties. Most of them were grown in the same vineyard. Four white (Calardis Blanc, Muscaris, Sauvignac, Cabernet Blanc) und three red (Satin Noir, Cabernet Cortis, Laurot) FRGV were compared to Riesling, Sauvignon blanc, Muskateller, Cab. Sauvignon and Merlot. For each FRGV, different styles were vinified using standardized protocols.

Aim: Climate modelling in viticulture introduced new challenges such as high spatio-temporal monitoring and the use of dependable time series and robustness modelling methods. Land surface temperature (LST) is widely used and particularly MODIS thermal satellite images due to their high temporal resolution (four images per day).

Rootstocks are used in vineyards worldwide and have been the focus of many studies. However, rootstock performance varies based on regional climates and soil types. As Oregon experiences warmer seasons and variable precipitation patterns, growers are interested in rootstocks with more drought tolerance than the commonly planted rootstocks: 3309C, Riparia Gloire, and 101-14 Mgt. In Oregon’s Willamette Valley, annual precipitation is typically sufficient to make dry-farming possible and use of irrigation is limited.