Impact of pruning method on vegetative growth and yield

Abstract

Over the past fifteen years or so, a number of theories have emerged on more or less new pruning practices. They promise vinegrowers better development of their vines, increased longevity, reduced esca rates and better performance. However, few scientific studies have been carried out to evaluate them. This study therefore proposes to investigate the impact of both respectful and non-respectful pruning practices on i) the vegetative expression of the vine ii) the yield iii) the expression of foliar symptoms of esca both on young vines since formation pruning and on adult vines whose usual pruning practices have been modified. So since 2020, 2 trials planted with Cabernet franc on 3309C on vines with 2m spacing between row and 1m spacing between vines have been carried out in a vineyard in south-west of France. The distribution of vegetative expression, and yield parameters between primary and secondary vegetation was quantified. The expression of esca leaf symptoms and mortality was recorded every year on a vine-by-vine basis. For the young vines, the first results show that respectful pruning provide the highest pruning weight and vigour but with higher proportion of suckers. On the other hand, the yield at the time of entry into production, is higher for the non-respectful pruning. On the adult vines there is no difference in total pruning weight, but twice as many suckers developed during the season with a higher proportion of clusters from suckers on the respectful pruning method. These preliminary results actually show differences in vegetative expression depending on the pruning methods applied. They are part of a long-term study and today, in this production context, it seems difficult to recommend the widespread adoption of a particular pruning method.