Phenolic Compounds, Phytohormones, and Biological Agents in the Post-Harvest Conservation of ‘Nanicão’ Banana Produced Under Deficit Irrigation

Banana is a nutritious food of great global economic importance. However, water deficit negatively impacts banana plant development. Therefore, it is essential to study efficient water use and develop technologies capable of maintaining fruit quality after harvest, extending the shelf life, and reducing losses. This study aimed to evaluate the efficiency of post-harvest applications of salicylic acid, gibberellic acid, and Trichoderma harzianum on ‘Nanicão’ banana fruits produced under controlled water deficit during different phenological stages, aiming to extend the shelf life and maintain nutritional quality. The experimental design was completely randomized in a 4 × 4 factorial scheme, comprising four irrigation management strategies based on crop evapotranspiration (ETc)—100% ETc throughout the cultivation cycle (E1) and 50% ETc during the juvenile stage (E2), fruiting stage (E3), and both juvenile/fruiting stages (E4)—and four post-harvest fruit conservation strategies: WC, control (distilled water); GA3, 200 mg L−1 of gibberellic acid; SA, 4.5 mM of salicylic acid; and TRIC, 1.5 mL L−1 of Trichoderma harzianum. There were four replications. The use of gibberellic acid at a concentration of 200 mg L−1 is the most effective strategy to extend the shelf life and maintain the post-harvest quality of ‘Nanicão’ banana fruits produced under water restrictions during the juvenile stage.