Chitosan Application Improves the Growth and Physiological Parameters of Tomato Crops

Tomato crops are treated with high concentrations of synthetic fertilizers and insecticides to increase yields, but the careless use of these chemicals harms the environment, human health, and plant pathogen resistance. The effect of the foliar application of three concentrations of chitosan (500, 1000, and 2000 mg L-1) on plant growth, yield, and physiological performance in two tomato varieties (Candela F1 and Floradade) was determined. Morphometric variables (height, stem diameter, and root, stem, and leaf dry biomass); production (number of bunches, number of fruits, and fruit weight), and physiological traits (water potential, gas exchange, leaf area index (LAI), and chlorophyll content (SPAD)) were evaluated throughout the experiment. Applying chitosan induced positive responses in biomass increase, yield, photosynthesis, SPAD, and LAI of the two tomato varieties. The responses of tomato plants to chitosan application were different depending on the variety evaluated, indicating a differential response to the biostimulant. Chitosan is an efficient compound to biostimulate the growth, positively modified the plants’ physiology, increasing the yield in both varieties of tomato. The use of chitosan in agriculture is a tool that has no negative effects on plants and the environment and can stimulate the productive capacity of tomato plants.