RESPOSTAS FISIOLÓGICAS E PRODUTIVIDADE DE MORANGUEIRO CULTIVADO COM BIOESTIMULANTES EM CONDIÇÕES DE DÉFICIT HÍDRICO

Abstract

This paper aimed to evaluate the effect of the bioestimulants PROGEN Detox and FERTILEADER Fix NG on the development of strawberry plants under water deficit conditions. The experiment took place in a greenhouse, employing a randomized block design within a split-plot arrangement, comprising three replicates and six plants per subplot, totaling 180 plants. The plot treatments consisted of two biostimulants (PROGEN Detox Br and Fertileader Fix NG), and the subplots received five foliar application doses of 0.0, 0.1, 0.2, 0.3, and 0.4 L ha⁻¹. The transplanted seedlings of the Camarosa cultivar were obtained from a certified nursery and grown in 14.5 L pots, filled up to 5 cm below the rim with fertilized and amended soil according to the plants’ requirements. Irrigation was carried out daily with three pulses per day, maintaining soil moisture close to field capacity. At 40 and 55 days after transplanting, the strawberry plants were subjected to water stress, reducing soil moisture to 50% below the optimal level during the flowering and fruiting stages. The evaluated variables were (a) chlorophyll fluorescence; (b) water use efficiency; (c) photosynthetic and transpiration rates; (d) stomatal conductance; (e) internal and external CO₂ concentrations; (f) electron transport; (g) chlorophyll A and B; (h) floral abortion; and (i) total yield. Physiological and postharvest evaluations were carried out in the morning, from 8 a.m to 11 a.m. Harvesting began at 120 days after transplanting. The following variables were analyzed: (a) fruit diameter and length; (b) soluble solids; (c) pulp pH; and (d) fruit color. Data were subjected to analysis of variance at a 5% significance level. In general, the biostimulants promoted positive physiological responses, such as increased fruit brightness, higher photosynthetic rates, and enhanced external carbon assimilation, especially under water stress conditions. However, they did not significantly influence yield or postharvest quality. The 0.2 L ha⁻¹ dose stood out as the most effective for enhancing the photosynthetic rate during flowering, indicating that biostimulants are a promising technology, although further studies under commercial production conditions are still required.