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Maintaining optimal grape acidity at harvest is one of the most complicated challenges under climate change pressures, especially in early ripening cultivars. Warming trends are compressing vine phenology and fostering berry malic acid respiration. In this work, over four years, we evaluated yield components and fruit ripening in two local varieties in the Colli Piacentini, Ortrugo (ORT) and Barbesino (BRB). Our goal was to evaluate their ability to maintain satisfying acidity at harvest and understand the limits and features of the genetic control over organic acid degradation during ripening. The two varieties exhibited comparable yield and grape total soluble solids (TSS) accumulation dynamics, but BRB showed consistently higher acidity during the entire ripening process in any of the four years. BRB's higher acidity was linked to higher malic acid concentrations. ORT had earlier onset of malic acid degradation than BRB and lower maximum malic acid degradation rates. Malic acid degradation rates were lower in ORT also later in the season, until harvest. However, correlations built between malic acid degradation rates and instantaneous malic acid concentration revealed that BRB had a consistently lower malic acid loss for values of malate < 10 g/L. Our work demonstrates that there is a genetic control over the malic acid degradation rates exhibited at varying malic acid concentrations and higher acidity at harvest can be found in varieties exhibiting low malic acid degradation rates when malic acid is < 10 g/L. Post-veraison berry growth rates could interact with genotype effects. The analysis of the correlation can be used at different scales to identify cultivars retaining higher acidity at harvest.

Summer pruning encompasses a series of operations typically performed on the grapevine during the growing season. This review provides an update on the research conducted over the last 20 years on the modalities and strategies of main summer pruning operations, which include shoot positioning and thinning, shoot trimming, leaf removal, and cluster thinning, with a special focus on their adaptation to climate change occurring in Mediterranean areas. Three main novelties emerged from the survey. First, due to a common need to shelter clusters against overheating and sunburn-related damages, shoot thinning and leaf removal are practices that are now being applied in a much more cautious and conservative manner. Second, the meaning of summer pruning is evolving because operations are being used as precious tools to direct ripening toward a desired direction rather than being received passively. Third, some operations, such as leaf removal, have disclosed very high plasticity, which means that, depending on the timing and modalities of the intervention, yield can be either increased or decreased and ripening anticipated or postponed. In an era where economic and environmental sustainability have to find a good compromise, cluster thinning is increasingly being depicted as an extraordinary operation that should be left to occasional occurrences of overcropping. Moreover, summer pruning is a tool through which growers can, to an extent, exploit the potentialities offered by climate change. For instance, the crop-forcing technique, under the different configurations of single and double cropping within the same season, has been trialed promisingly in several regions and cultivars. The principle of forcing is to unlock the dormant bud during the first year by removing at least the young organs present on the shoot within a time window between the end of the flowering and pea-size stages. In particular, when it is applied in a double-cropping mode, the preliminary results r