Effect of leaf-removal on physical and oenological parameters of ‘BRS Lorena’ grapes

The grapevine cultivar BRS Lorena, developed in Brazil by Embrapa, stands out for its disease resistance and distinct muscat aroma. To optimize enological potential, double pruning inverts the crop cycle, shifting harvest to winter, characterized by warm days, high thermal amplitude, and low rainfall, which enhances berry ripening and sugar accumulation. Leaf removal around clusters can further improve microclimate and grape quality. This study evaluated the effect of cluster-zone leaf removal on the physical traits and ripening curve of cultivar BRS Lorena (2.0 m × 1.0 m, single spur-pruned cordon) under double pruning management. The experiment used a randomized block design with two treatments (with and without leaf removal at the pea-size stage), four blocks of five plants (15 clusters evaluated per block). Data were subjected to Tukey's test and the ripening curve was submitted to regression analysis. Cluster and berry fresh weight, length, and width were evaluated, along with soluble solids (SS), pH, titratable acidity (TA), and maturity index at 135, 142, 149, 156, 163, 170, 177, and 184 days after pruning (DAP). At harvest, leaf removal increased SS (26.20 vs. 25.09 °Brix), pH (3.09 vs. 3.04), and maturity index (2.61 vs. 2.29), and reduced TA (9.88 vs. 11.51 g/L), without affecting physical cluster or berry traits. A significant interaction between DAP and treatment occurred for SS and maturity index, with defoliated vines showing a steeper increase. In conclusion, cluster-zone leaf removal at the pea-size stage enhances berry ripening and enological quality in 'BRS Lorena' without compromising agronomic components