Revolutionizing vineyard practices: Meta-analysis reveals effective techniques to combat climate change-induced early grape ripening

Vineyard techniques have been developed to delay grape maturity against the backdrop of climate change, which causes advanced grape maturation due to increased heat and water stress, impacting grape quality. Although various studies have explored this, the experimental conditions vary. Despite efforts to understand and mitigate these issues, current literature lacks a quantitative summary. A systematic, data-driven review of these approaches is therefore needed. Meta-analysis (MA) has been introduced into the field of agronomy by comparing the results of specific treatments in multiple similar studies through statistical methods, but there is a relative lack of research applying it to vineyard technology

In May 2022, Horticulture Research published a perspective entitled by “A systematic review and meta-analysis of vineyard techniques used to delay ripening”.

In this study, data was curated using the PRISMA statement, leading to a qualitative dataset of 51 studies with 297 Effect Size (ES) values and a quantitative dataset with 43 studies and 242 ES values. The full set of quantitative data (nES= 242) was assessed using p-curve and PET-PEESE methodologies, revealing effective vineyard practices for ripening delay. Meta-regression results for individual treatments of Antitranspirants (AT), Delayed Pruning (DP), and Late Source Limitation (LSL) showed significant ripening delays. For AT, factors such as application timing and environmental conditions were significant, with different compounds showing varying effectiveness. Compared to kaolin, antitranspirants were most effective when applied twice and closer to veraison, while di-1-p-menthane increased the ripening delay by about 1 °Brix. In DP, 64 ES values from 10 studies indicated an average ripening delay, with significant variability across studies. Pruning stage and YieldControl emerged as significant factors affecting the ES, with the effect of later pruning stages being more pronounced Delayed pruning, especially in low-yielding vines or at later stages of bud development, also significantly delays ripening. LSL treatments showed significant ripening delays, with variation in heterogeneity between the late defoliation and trimming subgroups. The LSL model identified significant effects of TSS maturity at control and treated grapes, as well as yield-related variables, indicating that higher yields favored ripening delay. Late defoliation or shoot trimming is effective in high-yielding vines, particularly for late-harvested varieties, but loses efficacy if yield decreases.

In summary, this meta-analysis synthesized data from 43 studies to evaluate vineyard practices for delaying grape ripening. This study highlights key factors influencing ripening delay, providing valuable insights for winegrowers to adapt practices to meet the challenges posed by climate change in grape ripening.

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References

Authors

Pietro Previtali^1,2,*, Filippo Giorgini³, Randall S. Mullen⁴, Nick K. Dookozlian^2,5, Kerry L. Wilkinson^1,2, and Christopher M. Ford^1,2

Affiliations

¹Department of Wine Science and Waite Research Institute, The University of Adelaide, PMB1 Glen Osmond, SA, 5064, Australia

²Australian Research Council Training Centre for Innovative Wine Production, PMB1 Glen Osmond, SA, 5064, Australia

³Department of Economy, Management and Statistics, University of Milano-Bicocca, I-20125 Milano, Italy

⁴Research and Development Statistics, E. & J. Gallo Winery, Modesto, CA 95354, USA

⁵Department of Winegrowing Research, E. & J. Gallo Winery, Modesto, CA 95354, USA

About Pietro Previtali

He is a research at the University of Adelaide. His research interests include Grape Berry Ripening, Grape Aroma Profile, Grape Quality and Composition, Grapevine Physiology, and Viticulture and Oenology.