Effects of different training systems and limited irrigation applications on cold storage of pitaya<i> (Hylocereus</i> spp.) fruits

Pitaya is a species valued for its aesthetically pleasing fruit, multifunctional uses, ability to bear fruit within a year of planting, and strong market potential. These characteristics have contributed to cultivation of subtropical regions. However, research on the postharvest storage of pitaya is limited, and existing studies show variability in storage conditions. Additionally, no studies have explored the effects of different training systems and deficit irrigation applications on pitaya storage. This study evaluated the effects of three training systems (Pole System, T-System, and Inverted U-System) and four irrigation regimes (FULL irrigation, 75%, 50%, and 25% deficit irrigation) on the cold storage quality of 'Vietnamese Jaina' pitaya cultivars' fruits. The fruits were stored at 10 degrees C and 80% relative humidity, and key quality parameters titratable acidity (TA), total soluble solids (TSS), weight loss, ascorbic acid content, sugar composition (glucose, fructose, sucrose), and antioxidant activity were measured at 10-day intervals. Results showed a gradual increase in weight loss (from 1.52% to 3.10%) and a decrease in ascorbic acid content (from 39.7 mg kg-1 to 32.9 mg kg-1) over storage. Sugar concentrations (glucose, fructose, sucrose) and antioxidant activity increased up to day 20 before declining. While irrigation treatments had minimal effects on most parameters, training systems significantly influenced fruit quality. The Pole System (Control) exhibited the highest TSS and ascorbic acid content, while the TSystem had the highest glucose and sucrose concentrations. The greatest antioxidant activity was found in the Inverted U-System. The results indicate that 'Vietnamese Jaina' pitaya fruit can be stored for up to 20 days at 10 degrees C and 80% relative humidity in all training systems and irrigation regime without significant loss of quality.