Reduction of the height of the canopy in fruit set and in pea size: vegetative, productive and maturation effects, in cv. Verdejo
Global warming is accelerating the technological ripening of the grape, with a loss of acidity, which requires that vineyard management can delay ripening to avoid it. The source-sink relation is essential for grape ripening, since it affects the distribution of photosynthates and substances derived from plant metabolism. A work is proposed to know the response of the vineyard to the drastic reduction of the foliar surface by trim down the shoots in cv. Verdejo. In 2020, in Valladolid, the height reduction of the canopy was studied according to treatments: T (control), without reduction; Rj (reduction in fruit set -j-), trim to half the length of all shoots; Rk1 (reduction in pea size -k-), similar to Rj; Rk2 (reduction + lateral leaflessness, in -k-). Trim was made by hand respecting a height of trellis vegetation of 60 cm. The experiment was designed in 4 random blocks, with an elemental plot of 12 control vines, in a bilateral Royat cordon. The reduction of vegetation did not significantly affect grape production, producing a decrease between 8% and 4%, but significantly reduced pruning wood, between 25% and 16%, due to a decrease in shoot weight. In the campaign after the reduction, 2021, neither the grape production nor the vegetative development were affected. The composition of the grape in 2020 was hardly affected by the reduction, since the harvest only had to be delayed up to five days to reach the same concentration of sugars as in the control vines.
The pH, total acidity and malic acid of grapes did not show notable changes, while tartaric acid was significantly favored and potassium increased slightly. Probably, the relatively low production level did not prevent a fairly normal development of the grape ripening, despite the drastic reduction in the leaves-clusters ratio.
Acknowledgements: PID2019-105039RR-C42 project (MCIN/AEI) and Junta de Castilla y León
Issue: ICGWS 2023
1Instituto Tecnológico Agrario de Castilla y León, 47071 Valladolid (Spain)