Increasing soybean productivity can be achieved by treating seeds with biostimulants. To this end, an investigation was conducted into the potential of a formulation prepared with clove es-sential oil (CEO) diluted in soybean oil for seed treatment. Soybean seeds were treated with CEO concentrations between 0.5 to 3.0 mL/L, and subjected to germination, vigor, and sanity analyses. The CEO at 1.6 mL/L exhibited favorable outcomes regarding germination, root length, and re-duced fungal infection. In this way, a two-crop field experiment evaluated soybean seeds treated with CEO at 1.6 mL/L. Soybean seeds treated with CEO in the field in 2021/2022 were not different from the controls. However, in 2019/2020, there was a higher percentage of emergence, nodulation, and production of 749 kg/ha more than in the industrial treatment. These results highlight the potential use of CEO as a biostimulant.

Secondary growth in garlic depreciates its visual aspect and thereby renders the crop unviable for trade. Therefore, farmers commonly reduce fertilization and impose drought and oxidative stress caused by high-dose pesticides to reduce secondary growth in garlic plants. However, these procedures can be considered adverse, unhealthy, and environmentally inappropriate. To remedy this scenario, we investigated whether spraying growth inhibitors would prevent secondary growth in garlic plants. First, we evaluated the effects of abscisic acid, trinexapac-ethyl, chlormequat chloride, and paclobutrazol treatments on garlic plants grown in polyethylene tanks (250 m³). We then analyzed the effects of deficit irrigation combined with the application of trinexapac-ethyl (sprayed two or three times) and the application of trinexapac-ethyl, chlormequat chloride, or paclobutrazol alone (each sprayed two or three times) on garlic plants grown in the field, comparing them with the effects of deficit irrigation (control treatment) alone. The in-field experiment was replicated with the following treatments: control (deficit irrigation) and trinexapac-ethyl (sprayed two or three times) treatments. We analyzed the physiological, biometric, and production parameters affecting secondary growth in garlic plants. We observed that trinexapac-ethyl could efficiently regulate secondary growth without causing physiological disturbances in garlic plants. Our results provide valuable information that will contribute to the development of a sustainable technique to replace the current practices used by farmers to prevent secondary growth in garlic plants.

Garlic cultivation in tropical regions, such as the Brazilian Cerrado, faces the problem of secondary growth in the field induced by climatic conditions, which affects bulb quality and value. Clove essential oil (CEO) contains high levels of eugenol, which has the potential as an eco-friendly plant growth retardant (PGR) capable of reducing or inhibiting the secondary growth of bulbs in garlic cultivation. In this study, field experiments were carried out in two consecutive years (winter 2021 and 2022), spraying garlic plants with different concentrations of emulsion of CEO (0.0, 0.2, and 0.4%) in the differentiation phase; for comparison, the effects of water deficit, a prevalent agricultural technique in the region, were also evaluated. At a dose of 0.4%, the CEO reduced the prevalence of secondary growth and split bulbs without affecting yield. The mode of action of PGR was investigated by analyzing photosynthetic, enzymatic, and metabolomic parameters. The plants reduced amylolytic activity, and the photosynthetic parameters, after 7 days, were restored in both treatments. The analysis of the metabolomic profile of garlic leaves revealed changes in the pathways associated with the biosynthesis of fatty acids, wax, cutin, and suberin in plants treated with CEO, indicating possible damage to the surface coating of the leaf.

Few studies present interactions among plant physiological and seed chemical composition of soybean cultivates under different arrangements. Therefore, this study seeks to understand this relationship between space occupation and product quality. We grew two soybean cultivars (Tec 7849 Ipro and Monsoy 6972 Ipro) in four different spatial arrangements (50.0 x 7.1; 40.0 x 8.9; 30.0 x 11.9 and 18.9 x 18.9 or 16.2 x 16.2 cm, respectively). During V4 and R2 phenological stages, we analyzed the gas exchange, and at the harvest were composed two different lots: freshly harvested seeds and the seeds subjected to accelerated aging; in both lots, we evaluated germination test, vigor, germination speed index, seedling fresh mass, and the determination of the chemical composition of the seeds. For experiment conducted to analyze physiological parameters we adopted the factorial scheme 2x2x4 (two evaluation periods x two soybean cultivars x four spatial arrangements), and for seed quality and chemical composition, we adopted the factorial scheme 2x4 (two soybean cultivars x four spatial crop arrangements). The vegetative stage was crucial for better gas exchange efficiency, and the spatial arrangements positively influenced the physiological and chemical quality of the seeds for soybean crop, where the fitted arrangement was observed in 40.0 cm between rows and 8.9 cm between plants for the cultivar Tec 7849 Ipro and 50.0 cm between rows and 5.3 cm between plants, for Monsoy 6972 Ipro. Adjusts in spatial arrangements can promote beneficial responses in seed quality.