Seaweed extract biofertilizer modulates scarlet eggplant tolerance to salt stress

The present study aimed to analyze the application of a seaweed biofertilizer as an attenuator of salt stress on the morphophysiology of scarlet eggplants. The experiment was carried out under protected conditions in Areia, PB, Brazil, using an incomplete factorial arrangement in a randomized block design with four replications and two plants per plot by adopting the Box Central Composite Design with five electrical conductivities of irrigation water – ECiw (0.50 – control, 1.15, 2.75, 4.35 and 5.00 dS m−1) and five concentrations of seaweed biofertilizer (0 – control, 1.45, 5.00, 8.55 and 10 mL L−1). The electrical conductivity of irrigation water at values starting at 0.5 dS m−1 negatively affected the growth of scarlet eggplants. Therefore, the crop is considered sensitive to salt accumulation. The increase in electrical conductivity of irrigation water negatively affected the morphophysiology of scarlet eggplants, with reductions higher than 10% at electrical conductivity values higher than 1.37 dS m−1. Biofertilization at 6.67 mL L−1 mitigates the effects of salt stress on the gas exchange variables and the phytomass accumulation of scarlet eggplants 60 days after sowing. The seaweed biofertilizer can be used to improve the physiological and morphological performance of scarlet eggplants.