INOCULAÇÃO DE BACTÉRIAS PROMOTORAS DE CRESCIMENTO Bacillus subtilis E Burkholderia seminalis NA MITIGAÇÃO DO DÉFICIT HÍDRICO NA CULTURA DO TOMATE (Solanum lycopersicum)

Abstract

Management strategies have been developed aiming to mitigate the effects of water deficit on plants. Using plant growth-promoting bacteria (PGPB) in agriculture has stood out, as they act symbiotically in plants, promoting their growth. In this sense, this paper aimed to evaluate the inoculation effects of Bacillus subtilis ATCC 23858 and Burkholderia seminalis TC3.4.2R3 on the plant morphological characteristics, fruit technological attributes, and common cherry tomatoes productivity subjected to induced water deficit. For this purpose, two production cycles were chosen, consisting of two different designs: (a) randomized block design (RBD) with three treatments [inoculation with Bacillus subtilis ATCC 23858, Burkholderia seminalis TC3.4.2R3, and without inoculation (WI)] in eight blocks; (b) randomized block design analyzed in a 4x3 split plot scheme with four levels of water replacement [40%, 60%, 80%, and 100% of crop evapotranspiration (ETc)], and three inoculation types (Bacillus subtilis ATCC 23858, Burkholderia seminalis TC3.4.2R3, and without inoculation). The data were subjected to analysis of variance (ANOVA) by the F test and compared by the Tukey test (P<0.01 and P<0.05). Multivariate statistics were also applied based on principal component analysis (PCA) to complete the analysis. For the cycle (a), at 30 days after sowing (DAS), the seedlings inoculated with Bacillus subtilis and Burkholderia seminalis differed statistically (P<0.01) in relation to the treatment without inoculation for emergence speed index (ESI), aerial part fresh mass (APFM), aerial part dry mass (APDM), and root length (RL). Burkholderia seminalis provided a higher germination rate (P<0.05) in relation to the WI treatment, while Bacillus subtilis provided (P<0.01) greater plant height, fresh root matter (FRM), and dry root matter (DRM) in relation to the WI treatment. Inoculation with Bacillus subtilis and Burkholderia seminalis increased productivity compared to treatment without inoculation by 9.56% and 4.3%, respectively. The fruit soluble solids content increased by 9.25% and 12.33% due to the plant inoculation with Bacillus subtilis and Burkholderia seminalis in relation to the treatment without inoculation. Inoculation also promoted greater mechanical resistance of the fruits regarding compression and puncture. In principal component analysis (PCA), the sum of the variance corresponded to 64.84% of the total data set. Therefore, inoculation with Bacillus subtilis and Burkholderia seminalis promotes plant growth and productivity, and brings qualitative increases to the fruits, highlighting their potential in sustainable agricultural management. For cycle (b) inoculation with Burkholderia seminalis TC3.4.2R3 increased the fresh and dry mass contents of aerial part, the root content, and root volume. Inoculation with Bacillus subtilis ATCC 23858 increased the levels of carotenoid and chlorophyll b. Both inoculations increased the plant leaf water content in plants with more severe water deficit (40% ETc). The use of strains such as plant growth-promoting bacteria (PGPB) did not affect the fruit quality, except for the soluble solid content. Fruits from inoculated plants became lighter and with a greater number of fruits per bunch, resulting in greater productivity. Higher levels of water replacement promoted greater productivity.