https://ri.ufs.br/jspui/handle/riufs/2152 2026-10-28T07:24:00Z https://ri.ufs.br/jspui/handle/riufs/26206 Title: Tratamento de sementes com microrganismos benéficos: vigor e respostas fisiológicas de plântulas Authors: Vieira, Matheus Emannuel Oliveira Abstract: Modern agriculture requires technologies capable of enhancing the productive efficiency and sustainability of agricultural systems while reducing reliance on chemical inputs. In this context, the use of beneficial microorganisms for seed treatment represents a promising strategy to directly influence germination, vigor, and early plant establishment. This thesis integrates studies on bio-inputs, bacteria, osmoprotective solutions, the isolation and characterization of the biotechnological potential of mixed microbial cultures, and the induction of systemic resistance, with an emphasis on utilizing microbial resources and developing technologies applicable to regional agricultural conditions. Chapter 1 details the development of a technological solution for treating stored soybean seeds, combining microorganisms with an osmoprotective matrix to improve seedling vigor. Various imbibition periods and microbial treatments were tested, revealing that the response depends on the formulation's composition and application conditions. The treatment promoted early growth characteristics and vigor in soybean seedlings, highlighting the potential for developing formulations for biological seed treatment. Chapter 2 evaluates the biopriming of maize seeds with Bacillus amyloliquefaciens, assessing germination, seedling morphology, and the activity of antioxidant enzymes— specifically superoxide dismutase, ascorbate peroxidase, and catalase. While germination rates remained unchanged, exposure time proved crucial for seedling vigor, growth, and antioxidant metabolism. A four-hour exposure yielded positive responses, whereas six hours of exposure was associated with reduced vigor and increased ascorbate peroxidase activity, reflecting a higher antioxidant demand. These chapters demonstrate that contact time is a decisive variable; appropriate durations foster balanced physiological responses, whereas prolonged exposure can alter metabolism and compromise vigor. In Chapter 3, mixed microbial cultures were screened, and their biotechnological potential was evaluated regarding inorganic phosphorus solubilization, *in vitro* antagonism against the fungus Macrophomina phaseolina, and germination in bean and soybean crops. In Chapter 4, a systematic review gathered evidence on systemic resistance induced by beneficial microorganisms. Trichoderma, Bacillus, and Pseudomonas stood out as key genera involved in activating plant defenses, a process mediated by genes, proteins, enzymes, reactive oxygen species, and hormonal pathways linked to jasmonic acid, salicylic acid, and ethylene. Collectively, these studies provide insights into the efficiency of bio-inputs and highlight how performance depends on the interplay between the microorganism, formulation, plant species, application timing, and environmental conditions. Overall, the results reinforce the potential of the evaluated bio-inputs but also demonstrate the need for further research into stability, compatibility, microbial survival, and agronomic validation across different production conditions. 2026-07-21T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/26205 Title: Biotecnologia, silvicultura e importância socioeconômica do umbuzeiro no semiárido brasileiro Authors: Nascimento, Augusto Vinícius de Souza Abstract: The umbu tree (Spondias tuberosa Arruda) is a fruit species native to the Caatinga, with high ecological, socioeconomic and cultural importance for the Brazilian semi-arid region. Despite its potential for food production, income generation, biodiversity conservation and seedling production, the species still presents limitations related to propagation, dormancy of dispersal units, initial establishment and the scarcity of consolidated biotechnological and silvicultural protocols. In this context, this thesis aimed to evaluate biotechnological, silvicultural and socioeconomic aspects related to the umbu tree, in order to support strategies for propagation, seedling production, conservation and sustainable use of the species. Article 1 addressed the Anacardiaceae family, with emphasis on the diversity, uses and socioeconomic importance of native species for the Brazilian semi-arid region. The study highlighted the umbu tree as a strategic species of the Caatinga, due to its food, cultural, economic and environmental value. Article 2 presented a systematic review on umbu tree propagation, gathering studies published between 1991 and 2025. The results showed advances in seed technology, mineral nutrition, seedling production and vegetative propagation, but also gaps related to micropropagation, germplasm conservation and the standardization of vegetative propagation protocols. In Article 3, the effects of mother trees and provenances on dispersal unit biometry, seedling emergence, and initial seedling growth were evaluated. Differences were more evident in biometric attributes and emergence variables, while initial growth showed less pronounced or occasional responses among mother trees.. In Article 4, seedling production was evaluated under different light conditions and doses of controlled-release fertilizer. Moderate doses favored seedling growth and quality, whereas high doses compromised the morphological balance of the plants. In Article 5, the reuse of culture medium residues was evaluated as an alternative for seedling production. The application of these residues showed potential to promote initial growth and seedling nutrition, especially at specific application periods, suggesting their potential as a sustainable input for nursery seedling production.. In Article 6, the in vitro germination of seeds after endocarp removal was investigated, considering different mother trees, provenances and culture media. The removal of this structure favored germination and reduced limitations associated with slow and uneven emergence, as well as contamination of dispersal units. In Article 7, strategies for in vitro culture and micropropagation of the umbu tree were evaluated, involving different culture conditions, medium compositions, plant growth regulators and explant types. The results indicated distinct responses according to the treatment, reinforcing the need for specific adjustments for the establishment, multiplication and in vitro development of the species. Overall, the results demonstrate that the propagation and seedling production of the umbu tree depend on the integration of mother tree selection, management of dispersal units, removal of barriers imposed by the endocarp, adjustments in in vitro culture, and appropriate silvicultural practices. 2026-07-30T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/26204 Title: Metabólitos vegetais e microbianos no controle de fitobactérias associadas à mandioca: Enterobacter cloacae E Xanthomonas phaseoli pv. manihotis Authors: Gois, Larissa de Souza Abstract: Cassava (Manihot esculenta Crantz) is a crop of major socioeconomic importance, particularly for smallholder farming, but its production is severely constrained by bacterial diseases, including cassava bacterial blight caused by Xanthomonas phaseoli pv. manihotis (X2) and emerging soft rot associated with the Enterobacter cloacae complex (X6). Disease management relies mainly on copper-based compounds and antibiotics, whose effectiveness has been compromised by the emergence of resistant bacterial populations and environmental concerns, highlighting the need for sustainable alternatives. This study investigated plant- and microbial-derived metabolites as biocontrol agents against phytopathogenic bacteria. Initially, essential oils from different accessions of Lippia gracilis and their major constituents, thymol and carvacrol, were evaluated for their antimicrobial, antibiofilm, antivirulence activities and mechanisms of action against the Enterobacter cloacae complex. Subsequently, E. cloacae associated with cassava soft rot was isolated and characterized, followed by the evaluation of cell-free supernatants produced by Bacillus velezensis RT241 and Streptomyces sp. DN246. Antagonism assays, minimum inhibitory and bactericidal concentrations, growth kinetics, cell viability, biofilm formation and eradication, motility, DNA/RNA and protein leakage, hydrolytic enzyme production, and scanning electron microscopy were performed. Essential oils from L. gracilis exhibited pronounced antimicrobial and antibiofilm activities against the E. cloacae complex. Cell free supernatants of B. velezensis RT241 and Streptomyces sp. DN246 showed strong antibacterial activity, with growth inhibition of 90% against X2 and 87% against X6, reduced cell viability (80–87%), eradication of mature biofilms (98% for X2), increased DNA/RNA (58%) and protein (75%) leakage, and ultrastructural alterations consistent with severe membrane damage. Streptomyces sp. DN246 showed the greatest ability to prevent biofilm formation, reaching 93% inhibition against X2 and 82% against X6. Overall, the results demonstrate that metabolites produced by L. gracilis, B. velezensis, and Streptomyces represent promising candidates for the development of sustainable bioinputs for the management of cassava bacterial diseases and other phytopathogenic bacteria. 2026-07-30T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/25924 Title: Enviromics e modelagem preditiva aplicadas ao melhoramento de milho (Zea mays L.) no semiárido brasileiro Authors: Martins, Gabriel Oliveira Abstract: Maize (Zea mays L.) is a strategic crop for food security, forage production, and income generation in the Brazilian semiarid region. However, high climatic variability and edaphic constraints result in low average productivity and elevated risk of crop failure, while also hindering the recommendation of adapted cultivars. In this dissertation, we propose an integrated framework that combines envirotyping, environmental stratification, geospatial delineation of the target population of environments (TPE), and the multi-trait mean performance and stability index (MTMPS) to support maize breeding and cultivar recommendation in the semiarid region. In the first study, the envirotyping approach was applied across selected states of Northeastern Brazil, delineating four mega-environments (MEs) based on 19 environmental covariates, ten experimental sites, and a 23-year climatological series. Across the ten environments, 20 maize hybrids were evaluated over two growing seasons, and the MTMPS was employed to select superior genotypes, simultaneously assessing grain yield (GY), plant height (PH), ear height (EH), plant density (PD), and number of ears (NE). This approach enabled the identification of productive hybrids combining high mean performance and greater consistency across the two growing seasons per ME, with G03 and G04 standing out as selected across three of the four MEs. The integration of envirotyping and MTMPS enabled the simultaneous assessment of mean performance and stability across multiple traits and may support the future rationalization of multi-location trial networks. In the second study, environmental covariables were used – through the EnvRtype package in R – to segment the Alto Sertão Sergipano into macroenvironments (MEs) based on similarities among environmental and ecophysiologically relevant covariates. Cluster analysis revealed four major environmental groups, showing that neighboring municipalities may belong to distinct climatic zones, while geographically distant areas may share similar environmental profiles. This stratification highlighted the possibility of reducing the number of testing sites by concentrating trials in more representative environments, thereby providing a basis for future environmentally informed cultivar evaluations for the region. In the third study, we developed a georeferenced TPE for maize in the Alto Sertão Sergipano using geographic information system (GIS) tools in R, including the TPEmap function. Based on the coordinates of 21 georeferenced locations, concave polygons were built, rasterized, and integrated with climatic and soil covariables (NASA POWER and SoilGrids v2.0). Cluster analysis, the environmental similarity matrix, and principal component analysis revealed that the TPE is structurally heterogeneous and composed of six edaphoclimatic sub-environments, reflecting gradients of aridity, temperature, and water availability. Using grain yield data from 352 genotypes evaluated at CEUFS (2019– 2024), mixed models (REML) were fitted to estimate BLUPs and rank genotypes for productivity and stability. Cultivars AGR Vereda, NS80VIP3, GNZ59, GNZ15, and AG8780 comprised the elite group, with high predicted performance and temporal consistency at CEUFS, which belongs to the central environmental cluster of the TPE. Taken together, the results indicate that integrating envirotyping, environmental stratification, geospatial TPE mapping, and MTMPS provides an environmentally informed basis for redesigning experimental networks, guiding breeding programs, and the future evaluation and recommendation of maize cultivars for the Brazilian semiarid region, with the potential to contribute to productivity, resilience, and food security following multi-location validation in the Alto Sertão Sergipano and similar regions. 2026-07-14T00:00:00Z