Effects of prunning levels on yield, fruit maturity and reserves in malbec vineyards trellised to single high-wire system

GASTÓN E. AHUMADA; PIRRONE MIGUEL ; SEGURA DANIELA; BELMONTE MARCELO; GIORDANO CARLA V.; CARINA V. GONZÁLEZ

Congreso; XXXIII Argentinean Meeting of Plant Physiology; 2021

The main objective of winter pruning of grapevines is to regulate vegetative and reproductive growth. Pruning level affects budbreak, leaf area development, maturity, yield and reserve levels. In this work, we evaluated for the first time in Argentina, the effect of different pruning levels on leaf area development, yield, grape maturity and reserve levels of Malbec vineyards trellised to a SHW system in Mendoza. We imposed different winter pruning levels during three growing seasons 2017, 2018 and 2019: 16, 24, 32 and > 32 buds per meter of productive cordon (buds m-1). We measured total leaf area (TLA) at veraison, yield and fruit composition at harvest and structural reserves in trunk at leaf fall. Soluble solid concentration (oBrix)in berries was similar among treatments with the exception of 2018 where 16 buds m-1 that presented the highest values. In general terms, we found that the interannual variation of reserves (starch) in trunk was inversely correlated with yield interannual variation. 24 and >32 buds m-1 presented high yield and high levels of reserves, 16 buds m-1 presented high levels of reserves, but lower yields. Meanwhile, 32 buds m-a presented high yield but was not sustainable over time due to their decrease in reserve levels in the third year. > 32 buds m-1 reached its highest TLA and reserve levels in the third year, indicating tat this is the minimum period necessary to stabilize its yield and reserves at sustainable levels over time