Bacillus velezensis and halotolerant strains isolated from salime soils as growth promoters of maize (Zea mays L.) in greenhouse

Abstract

Objective: To evaluate the effect of Bacillus velezensis and four halotolerant strains, isolated from saline soils in the Lambayeque Region (Peru), as growth promoters of maize plants under greenhouse conditions. Methodology: The study began with the isolation of bacteria from agricultural soils with salinity problems and the selection of sodium chloride-tolerant strains, designated M6S, strain 1, strain 2, and strain 3. The previously identified halotolerant bacterium B. velezensis was also used. In the greenhouse, maize (Zea mays L.) 'Pioneer' plants were sown directly in pots with two plants per experimental unit and three replicates per treatment. The bacterial strains were evaluated with two and three inoculations, a control with chemical fertilizer, and an untreated control for 60 days. Plant height, vigor, root development, and shoot and root biomass were evaluated. Data were analyzed using ANOVA and Duncan's test (p ≤ 0,05). Results: Strains 1 and 2, with three inoculations, significantly increased plant height compared to the control (41,68 % and 42,78 %, respectively). In terms of vigor, strains 1, 2, and 3 reached grade 6 (very vigorous and leafy). Regarding root development, all strains achieved grade 6; aboveground dry biomass was equal to or greater than that of the chemical fertilizer; furthermore, strain 2 exhibited the greatest root biomass. Conclusions: The halotolerant strains isolated from saline soils (M6S, strain 1, strain 2, strain 3) and B. velezensis demonstrated the capacity to promote maize growth under greenhouse conditions.