Pruning is a common agrotechnical practice in
vineyards, directly affecting the vegetative and reproductive development of
the vines. The present research deals with a relatively new agrotechnical
method of pruning termed "late shoot pruning" (LSP), or "late
pruning". This method of pruning is performed in the spring (April) after
budburst have occured. The purpose of the study was to examine the effect of
three dates of pruning on the phenological development, canopy area, and vines
The study was conducted in a commercial vineyard
near Mevo Horon planted with Vitis vinifera cv. Malbec, for two consecutive
yeras (2016-2017). Five treatments were tested:
1. Winter pruning.
2. Winter pruning and cluster thinning (one
cluster per shoot).
3. LSP performed 7 days after budburst.
4. LSP performed 14 day after budburst.
5. LSP performed 21 day after budburst.
The findings suggested that LSP significantly
affected the phenological development of the vines. The LSP lead to a delay of
the onset of budburst, which was manifested later in the season in delayed
development of canopy. The younger leaves showed an improved carbon fixation
and stomatal conductance, as well as a less negative midday stem water
potential. In addition, we observed a phenomenon of "natural" cluster
thinning due to the application of LSP treatments. These effects eventually
resulted in improved must and wine parameters as reflected in the significantly
higher wine tasting scores of the LSP treated vines.
Post-budburst pruning practice was found to have
a positive effect on physiological and agrotechnical indices and on the quality
of wine obtained, compared to standard pruning (with and without cluster
thinning) in the Malbec cultivar. This study has significant commercial
implications for the grape and wine industry, since performing a simple and
inexpensive practice at the proper timing affects thinning of the cluster,
saves labor, and improves the quality of the final product.