The production of Malbec in three different pruning alternatives

BERLI F.; CORVALAN A.; GALARRAGA I.; CARRILLO N.; RODRIGUEZ J.; BERGAS V.

Punta del Este

Congreso; XLI World Congress of Vine and Wine; 2018

Organización Internacional de la Viña y el Vino (OIV)

The traditional Malbec vineyards of Mendoza province (Argentina) were mostly located in the so-called "First Zone", Luján de Cuyo city. They were trained in short (low) vertical shoot positioned systems of 1.5 m height, pruned in Double Guyot (2 spurs and 2 canes), irrigated by furrows and with an intensive tillage of soil. The modern viticulture of the last 25 years has been developed to a great extent in the Uco Valley, a piedmont area that goes from 950 m a.s.l. to 2000 m a.s.l. It is characterized by the implantation of varieties with high qualitative potential, the use of dripped irrigation, the high vertical shoot positioned trellis systems, the used of bilateral cordons (spurs pruning), the minimum tillage of soils and the quasi-integral mechanization of the vineyard. Although the tendency to mechanization is growing, lately both technicians and producers are reassessing the use of short pruning systems. When this is not well done, the permanent cordons lose productivity due to a lack of spurs positions and aging that forces to have to renew them frequently. In these situations, large cuts must be made, exposing the wood to the entry of pathogens. In turn, the operation of shoot thinning in the bilateral cordon is much more intense compared to the guyot system. Cane pruning allows the budbreak of buds located between nodes 4 to 8 from the base of the shoots. Numerous researches have shown that fruitfulness in Vitis vinifera is higher in the middle third of the shoot and lower in the basal and apical portion, therefore buds from the middle third are more productive. The present work compared three types of pruning in a commercial vineyard of Vitis vinifera cv Malbec located in the Uco Valley, with serious problems of productive instability and low yields. The treatments applied were the following: spur pruning (bilateral cordon), mixed pruning (double guyot) and no pruning. We randomly selected 6 bays of each treatment whose plants were pruned in the 3 mentioned systems. Different variables were evaluated: yield per plant, cluster weight, number of berries per cluster, bud fruitfulness and percentage of budbreak. The results showed that when comparing the 3 pruning systems in a year, yield per plant was higher in the plants without pruning compared with the plants with spur and cane pruning. In turn, in the plants without pruning, clusters from the apical buds didn?t present significant differences neither in the number of berries nor in their weight with respect to clusters from the buds of the middle third. Regarding yield components, plants without pruning presented lower cluster weight, less number of berries per cluster and smaller berry size, compared with spur and cane pruning. Plants with cane (Guyot) had a higher bud fruitfulness but a lower budbreak percentage than plants with spur pruning (bilateral cordon). This work adds information about the main differences in the different pruning alternatives for Malbec cultivar. At the same time, it poses a question about the possibility of training Malbec in minimal pruning or not pruning systems.