Effect of Bacillus Subtilis Inoculation and Foliar Application of Iron and Manganese on Physiological Characteristics and Yield of Tomato (Solanum lycopersicum L.) Grown Under Protected Cultivation

Abstract

The present study was aimed to evaluate the combined and individual effects of Bacillus subtilis inoculation and foliar spraying of iron (Fe-EDTA) and manganese (MnSO4) on the growth, physiological responses and fruit yield of tomato (Solanum lycopersicum L. cv. Super Strain B) grown in greenhouse condition. The experiment was conducted as factorial experiment based on randomised complete block design with three replications over the 2023-2024 crop season. The treatments consisted of two bacterial inoculation levels (with and without B. subtilis at 108 CFU mL-1), three foliar Fe-EDTA concentrations (0, 50 and 100 mg L-1) and three foliar MnSO4 concentrations (0, 25 and 50 mg L-1). The interaction of B. subtilis inoculation with 100 mg L-1 Fe-EDTA and 50 mg L-1 MnSO4 significantly (p < 0.05) maximised plant height, leaf area index, total chlorophyll content, net photosynthetic rate and total fruit yield per plant over all other treatments and uninoculated–unsprayed control. Individual bacterial inoculation improved root colonisation and nutrient uptake and micronutrient sprays addressed latent Fe and Mn deficits. These data indicate that the use of biofertilizer combined with certain foliar micronutrition supplementation is a promising technique to increase tomato yield in protected growing systems.
Highlights
Bacillus subtilis inoculation enhanced root colonisation and nutrient uptake in greenhouse tomato.
Foliar Fe-EDTA at 100 mg L⁻¹ significantly increased chlorophyll content and photosynthetic efficiency.
Combined bacterial + Fe + Mn treatment produced the highest fruit yield and quality parameters.
Manganese foliar application improved antioxidant enzyme activity and fruit firmness.
Integrative biofertiliser–micronutrient strategy offers a sustainable alternative for protected cultivation.