Simultaneous Effects of Shade Nets and Different Water Supplies for Mapping Multiple Physicochemical Traits of ‘Jonagold’ Apple: Insights from a High-Density Orchard in Iran

This study was conducted in a randomized complete block design with a split-plot arrangement in a high-density ‘Jonagold’ apple orchard. The shade nets including no shade (N0), one-layer net (N1), and two-layer net (N2) and deficit irrigation (with 100, 85, and 70% of water requirement) were thought to exist in primary and secondary plots, respectively. The results showed that the influence of shades on microclimate significantly differed. The intercepted light values showed a significant difference between the shading treatments, with the mean water requirement in N0 being the most significantly abundant. Shade nets significantly contributed the most in total flavonoid content and the ratio of total soluble solids (TSS) and titratable acidity (TA). The TSS/TA ratio was statistically higher in N0 than for both shade net values. Current ratios showed the same statistic values for N1 and N2. Fruit weight, firmness and size also differed significantly among shadings. Fruit weight of N0 was significantly less than N2 samples. The fruit sunburn was significantly mitigated by shading. In different shades, the significantly highest levels of catalase, ascorbate peroxidase, and proline contents were observed in N0. The significantly highest content of chlorophyll was observed within the 100% of water requirement. Shade was associated with a significant increase in electrolyte leakage and leaf area index; however, it significantly decreased specific leaf weight. The protected cultivation provided can be considered a promising solution to increase crop yield and quality.