Effect of Dormancy Disruptors on Development and Yield in ‘Golden Delicious’ Apple Trees

Resumen

Objective: To evaluate the effect of dormancy-breaking agents on the developmental and yield components of the 'Golden Delicious' apple tree.

Design/methodology/approach: Treatments were applied during the 2018, 2019, and 2020 growing seasons using a randomized complete block design with three replications in a factorial arrangement. Factor A was the year (2018, 2019, 2020), Factor B was the type of dormancy-breaking agent, and Factor C was the concentration of each agent. Evaluated variables included vegetative growth, number of nodes and buds on one- and two-year-old shoots, budbreak percentage, and yield parameters such as fruit weight, equatorial and polar diameter, firmness, and total production.

Results: Budbreak in one- and two-year-old shoots improved with hydrogen cyanamide at a concentration of 20 mL L⁻¹, achieving 76.8% budbreak in 2018, followed by thidiazuron at 0.4 mL L⁻¹ with 70.7% in 2018 and 74.3% in 2020. The highest yield (68.8 t ha⁻¹) was obtained with thidiazuron at 0.8 g L⁻¹, while the greatest firmness was recorded with BrotStart and hydrogen cyanamide applications, with 18.0 and 17.8 lb in², respectively.

Limitations/implications: The study was limited to a specific cultivar ('Golden Delicious') and conducted under the agroclimatic conditions of three growing seasons, which may influence treatment efficacy.

Findings/conclusions: ormancy-breaking agents significantly influence budbreak and yield in 'Golden Delicious' apples. Hydrogen cyanamide and thidiazuron were the most effective treatments, enhancing both vegetative development and production parameters, suggesting their suitability for improving apple orchard productivity in temperate climates.