Current review paper: A systematic review and meta-analysis of vineyard techniques used to delay ripening
Climate change is causing increasingly frequent water and heat stress events for crop growers. Vineyards have seen growing issues with accelerated grape maturation where grapes accumulate sugars quickly – leading to an early technical maturity but lagging maturity in terms of flavour and aroma, as well as logistical winery issues with vintage compression where large amounts of grapes ripen at the same time instead of spread out over the season.
A current review paper by researchers from the University of Adelaide, in collaboration with the University of Milano-Bicocca and E&J Gallo Winery, discusses practices to delay grape ripening to identify techniques that can be used by grape growers to obtain grapes with a better balance in sugar and phenolic ripeness. As opposed to earlier reviews on this topic, the current review paper is focused on quantitative analysis to truly understand if vineyard operations can effectively guide ripening delays.
Several techniques believed to delay sugar accumulation, decompress harvest and enhance grape quality were investigated in the review, with a specific focus on treatments such as antitranspirants, delayed pruning and late defoliation and shoot trimming, as these are most useful in vineyard management. The statistical technique utilized to synthesise results across sets of studies, called meta-analysis, was also used to evaluate the importance of parameters that can be easily manipulated by growers. The results of this analysis provided important pieces of information regarding the effect of parameters such as the timing or intensity of the treatments investigated, yield or crop conditions on the ripening delay, which can be now accounted for by growers when they plan to employ vineyard practices to delay ripening.
Find the review here.