Initial growth, production in consecutive years and biochemical changes on tomato cultivars in organic system with application of Bacillus subtilis

ABSTRACT In this study, Bacillus subtilis were applied on seeds, seedlings, and tomato crops for two years in an organic system. The product Serenade® was used on 'Cardyna' and 'Trinidade' cultivars with the objective of determining the effect of the bacteria on initial plant growth when applied to seeds (50 uL per seed) or the seedlings watered with 100 mL solution at 8 mL L-1 concentration, and tomato yield when applied at the concentration of 4 mL L-1 in the form of a soil drench, foliar sprays and their combination, considering their action in the promotion of growth and also in the induction of resistance allied to possible metabolic deviations. Seed application reduced initial plant growth, while seedling watering at transplanting promoted growth. Chlorophylls a, b and total chlorophyll, carotenoids, and the enzymes phenylalanine ammonia lyase, chitinase, and β1,3 glucanases were stimulated in a variable way among cultivars and applications, indicating the activation of plant defenses. Phenolic compounds, flavonoids, and total sugars were not altered, while the concentrations of reducing sugars were higher due to applications than those of non-reducing sugars. The metabolic changes did not influence the tomato yield.