Comparative evaluation of zinc nutrition approaches on growth, yield and fruit quality of tomato ( Solanum lycopersicum ) in field conditions using multivariate analysis

The availability of zinc is critical for promoting tomato growth and achieving superior fruit quality under deficient conditions. This study evaluated 12 zinc fertilization treatments across two growing seasons 2022–23 and 2023–24 to determine the most effective strategies for improving tomato performance in the field. The combined application of ZnSO4.7 H2O via seed priming, soil, and foliar spray consistently enhanced vegetative growth with plant height of 112.86 cm and canopy width (49.15 cm2), while accelerating flowering by 13.5 days as compared to the control. T10 increased total and marketable yield by 11.6% and 25.6%, respectively. It is important to note that foliar application alone (T4) was as beneficial as a combined application in terms of benefit–cost ratio, demonstrating its practical efficiency. Zinc treatments also improved fruit quality, increasing ascorbic acid content to 31.90 mg 100 g−1, TSS to 6.09 °Brix, and titratable acidity to 0.96%. Multivariate analysis rebealed that fruit weight, size, and number were important determinants of yield, whereas excessive vegetative growth negatively impacted productivity. These findings provide economically viable suggestions for zinc fertilization for sustainable tomato production and quality improvement.