Girdling shoots during bloom period decreases shatter in Malbec clusters

RODRIGUEZ J.; BERLI F.; CARRILLO N.; PICCOLI P.

Punta del Este

Congreso; XLI World Congress of Vine and Wine; 2018

Organización Internacional de la Viña y el Vino (OIV)

Knowing the scientific basis and developing management strategies to control the components of yield and quality in the production of Vitis vinifera L. is one of the main demands of the wine industry. Malbec, the most cultivated and important variety in Argentina, frequently presents shatter, that is clusters with few berries, that severely affects yields. Although different selection processes have been carried out for many years and there are currently improved clones, many commercial Malbec vineyards present a marked instability of their productive potential. Yield per plant, and consequently per hectare, is affected annually by a high incidence of shatter, and this may be due to low percentages of fruit set and / or an increase in the abscission of fruits after setting. The scientific background on the subject indicates that carbohydrates availability towards the inflorescences at bloom and fruit set is determinant in the final size of the clusters (number and size of berries). Girdling is a practice that permits the modification of the flow of reserves and photoassimilates in the shoot by removing a portion of phloem tissue through an annular incision, without affecting the xylem.The objective of the present project was to evaluate the effects of girdling at the beginning of bloom on clusters size and quality of Vitis vinifera L. cv. Malbec, in a commercial vineyard where the problem of shatter is severe. Four treatments were applied, a control without girdling, a girdled at the base of the shoot (first internode), a girdled above the last cluster (internode above the insertion of the cluster) and a double girdling (at the base and above). The variables evaluated were the percentage of fruit set, the size of clusters and the quality of grapes for each treatment.The results showed that a girdled at the base of the shoots causes an increase in the percentage of fruit set and a decrease in shatter. Clusters have a greater number of berries but those are smaller, so the qualitative parameters are not affected.This work provides new information about the practice of girdling as a tool to reduce shatter and increase Malbec productivity. In addition, it contributes to the knowledge of the dynamics of photoassimilates in the grapevine shoot.