Postharvest and Nutritional Response of Tomato to Foliar CaCl ₂ and MgO Treatments Under High‐Plastic Tunnel Environment

Tomato ( Solanum lycopersicum L.) is a vital crop whose yield and quality depend on nutrient management. This study examined foliar applications of calcium chloride (CaCl 2 ) and magnesium oxide (MgO) (0.5 and 1.0%) on the “Roma” cultivar under a randomized complete block design (RCBD) with four replications in controlled conditions. Data were analyzed using ANOVA in SPSS and R, with mean separation by Tukey's HSD test ( p ≤ 0.05). Pearson's correlations evaluated nutrients and fruit quality relationships. The 1.0% CaCl 2 treatment significantly increased fruit set (71.2%), yield (1.80 kg plant −1 ), firmness (5.47 N), and total soluble solids (5.32°Brix), while reducing weight loss (9.32%). Conversely, 1.0% MgO produced the most flower clusters (5.29 plant −1 ) and enhanced nutrient uptake. Heatmap analysis indicated strong positive correlations of calcium with fruit firmness ( r = 0.92) and ascorbic acid ( r = 0.88) and negative correlations with titratable acidity ( r = −0.70) and fruit weight ( r = −0.65). Magnesium correlated positively with ascorbic acid ( r = 0.76) and enhanced macronutrient uptake ( p ≤ 0.05). The findings show calcium strengthens cell walls and fruit firmness, while magnesium boosts photosynthesis and nutrient balance. Integrated foliar nutrition is recommended to improve tomato yield and quality under controlled conditions.