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The ripeness of a grape is critical to berry composition and to the resultant wine. For wineries with a single cultivar occupying an extensive area, the total soluble solid of grapes can range from 22°Brix to 28°Brix. Accordingly, the influence of different harvest dates (ripeness) on berry compositions and on the resultant wine profile was investigated for Vitis vinifera L. cv. ‘Cabernet Sauvignon.’ Berry dehydration was observed as berry weight and juice yields decreased. Berry anthocyanins were concentrated and methylated anthocyanin levels fluctuated with increasing delays in harvesting. Hexanal and 2-hexenal levels in must decreased significantly as berries ripened. In the resultant wines, 2,3-butanediol levels increased. Wines harvested earlier were lighter, presented lower color intensity (CI) values and higher yellow% levels, and exhibited richer aroma profiles (compounds). Through a principal component analysis and discriminant analysis, the compounds characterizing each harvest date were identified.

In this study, black geotextile inter-row mulch, a weed control practice, was applied under a semi-arid climate to attenuate solar reflection in 2015-2017, and it concurrently increased soil temperature and fruit-zone high temperature duration and decreased low temperature duration. Inter-row mulch decreased anthocyanins concentrations in grapes in 2015-2016, and consistently inhibited flavonols accumulation in 2015-2017. Correlation analysis between microclimate parameters and flavonoids concentrations reflected the importance of solar reflection, fruit-zone high and low temperature duration, heat accumulation and soil temperature to flavonoids accumulation. Basal leaf removal, a widely applied practice to increase fruit-zone light exposure, was applied to mulch-treated grapevines to investigate if increasing incident light could mitigate the impact of inter-row mulch on flavonoids, and it had limited influence on anthocyanins whereas compensated the loss of flavonols in grapes caused by inter-row mulch. Notably, inter-row mulch wines showed less red and more yellow color than controls because of lower anthocyanins concentrations.