Principais Coleções do Repositório
Submissões Recentes
dissertação
Seletividade de herbicidas pré-emergentes a cultivares de feijão-comum
(Universidade Federal de Lavras, 2026-07-10) Manoel, Pedro Lucas de Carvalho; Melo, Christiane Augusta Diniz; https://orcid.org/0000-0001-6385-2153; Moreira, Silvino Guimarães; https://orcid.org/0000-0002-3631-0305; Silva, Amilton Ferreira da; https://orcid.org/0000-0001-7122-2688; Carneiro, Vinícius Quintão; https://orcid.org/0000-0001-9697-1423
Common bean has a limited number of herbicides registered for pre-emergence application. In this context, this study aimed to evaluate the selectivity of different pre-emergence herbicides in four common bean cultivars. Four experiments were conducted per growing season, one for each bean cultivar, at the Center for Development and Technology Transfer (CDTT) of the Federal University of Lavras, in Ijaci, Minas Gerais, Brazil, during the 2024/2025 and 2025/2026 growing seasons. The experimental design was a randomized complete block design (RCBD), with four replications. Eleven herbicides were applied in pre-emergence, either individually or in mixtures, as follows (g a.i. ha⁻¹): flumioxazin + pyroxasulfone (80 + 120); flumioxazin + imazethapyr (100 + 200); S-metolachlor + fomesafen (1294 + 284); flumioxazin + S-metolachlor (31.5 + 630); ethoxysulfuron (24); flumioxazin (50); pyroxasulfone (150); imazethapyr (106); S-metolachlor (960); pendimethalin (910); and linuron (450), in addition to two controls, with and without mechanical weed control. Four common bean (Phaseolus vulgaris L.) genotypes were evaluated: IAC 1849, IAC 1850, IAC 2051, and TAA Marhe. Herbicides were applied immediately after crop sowing. Each plot consisted of five rows, six meters in length, spaced 0.6 m apart, with the three central rows considered the experimental unit. At 7, 14, 21, and 28 days after application (DAA), visual assessments of crop injury and weed control were performed in the useful area of each plot. Before harvest, the final bean plant population, plant height, number of pods per plant (NPP), and number of grains per plant (NGP) were evaluated. After bean harvest, the thousand-grain weight and yield were assessed, with yield corrected to 13% moisture content. Data were subjected to analysis of variance (ANOVA). When a significant effect was detected, herbicide treatment means were grouped using the Scott-Knott test at 5% significance level. In the 2024/2025 growing season, lower levels of crop injury and greater weed control efficiency were observed compared with the 2025/2026 growing season. It was concluded that ethoxysulfuron was selective for the TAA Marhe cultivar and S-metolachlor + fomesafen was selective for the IAC 1849 cultivar when applied in pre-emergence. The herbicides linuron, flumioxazin + S-metolachlor, S-metolachlor, S-metolachlor + fomesafen, flumioxazin, and pendimethalin were selective for the IAC 1850 cultivar, whereas linuron, flumioxazin + S-metolachlor, S-metolachlor + fomesafen, ethoxysulfuron, flumioxazin + pyroxasulfone, pendimethalin, and imazethapyr were selective for the IAC 2051 cultivar.
dissertação
Nostocaceae e Scytonemataceae isoladas de raízes de macrófitas aquáticas
(Universidade Federal de Lavras, 2026-06-30) Lima, Gustavo Henrique Pereira; Coelho, Flávia de Freitas; https://orcid.org/0000-0001-9338-8128; Abreu, Carlos Godinho de; https://orcid.org/0000-0001-6735-8283; Biondi, Michel; https://orcid.org/0000-0002-0848-325X; Vaz, Marcelo Gomes Marçal Vieira; https://orcid.org/0000-0003-1624-8281; Stein, Vanessa Cristina; https://orcid.org/0000-0003-1412-0874
Heterocytous cyanobacteria are nearly ubiquitous organisms, inhabiting a wide variety of environments across the Earth's crust. The organisms, classified within the order Nostocales, are characterized by the presence of heterocytes, specialized cells responsible for an exclusive and ecologically significant function: biological nitrogen fixation. This adaptation enables members of Nostocales to colonize nitrogen-poor environments and establish symbiotic associations with organisms from numerous branches of the tree of life. In this study, we present the morphological characterization and molecular identification of nine strains belonging to the families Nostocaceae and Scytonemataceae, deposited in the Filamentous Cyanobacteria Collection (CFC) of the Federal University of Lavras (UFLA). These strains were isolated from the roots of Pistia stratiotes L. and Salvinia auriculata Aubl. Morphological identification and characterization were performed through light microscopy observations supported by specialized taxonomic literature. For molecular identification, the 16S rRNA gene was employed as a molecular marker. Phylogenetic analyses were conducted using Bayesian inference implemented in MrBayes, generating one phylogenetic tree for each family investigated. Lineages were identified in genera derived from Nostoc Bornet & Flahault and a species of the genus Brasilonema Fiore et al. The lineage P6109 was identified as Cronbergia amazonensis Genuário et al.
tese
Avaliação do comportamento sensorial de edulcorantes de estévia com diferentes composições químicas aplicados em mousse de chocolate vegano
(Universidade Federal de Lavras, 2025-10-29) Freire, Tassyana Vieira Marques; Pinheiro, Ana Carla Marques; Abreu, Luiz Ronaldo de; Souza, Vanessa Rios de; Bastos, Sabrina Carvalho; Lago, Rafael Carvalho do
Evidence linking excessive sugar consumption to obesity and diabetes has driven changes in dietary habits. At the same time, consumer preference for natural ingredients and uncertainties regarding the safety of artificial sweeteners have increased interest in natural alternatives. Among these, steviol glycosides (stevia) obtained from Stevia rebaudiana stand out, although their acceptance must be evaluated in real matrices. Therefore, the objective of this study was to evaluate the replacement of sucrose with five commercial stevia samples (A, B, C, D, and E) in vegan chocolate mousse, integrating sensory and analytical methods to guide the technological selection of sweeteners. Initially, for comparative studies, 22 panelists were selected and trained according to ISO 8586/8589 (sequential Wald screening) and performed Magnitude Estimation using 10% sucrose as reference. The log-concentration vs. log-intensity relationships followed Stevens’ Power Law for both sucrose and stevia samples (R² ≥ 0.9605). Equivalent concentrations were <0.15% w/w and sweetness potency ranged from 67.71× to 332.28×. HPLC characterization revealed compositional heterogeneity (Rebaudiosides M, D, C, and rubusoside), and PCA (PC1 = 50%; PC2 = 39%) showed a positive association between sweetness potency and RM (Stevia D: high RM) and a negative association with rubusoside (Stevia B: higheer R and lower potency). Temporal sensory results (TDS) showed that while sucrose exhibited the expected TDS profile (dominant and prolonged sweetness), stevia samples presented shorter curves, unstable dominance, and rapid transitions among attributes. This behavior reflects the complexity of the matrix and the chemical–sensory interactions between bitter compounds and steviol glycosides. Matrix effects emphasize that the sensory performance of natural sweeteners must be interpreted in the context of the final application, as texture, fat content, and cocoa phenolic compounds may alter perception kinetics, enhancing bitterness perception of less glycosylated steviol glycosides (RC and R), as seen in samples with Stevia B and E, and interfering with the sensory dominance of compounds associated with dominant sweetness profile and without undesirable residual (RM and RD), even in samples with high sweetening power. In conclusion, although steviol glycosides are high-intensity sweeteners, their sweetness potency and temporal sensory profiles vary according to their chemical composition and interactions within the food matrix. These findings reinforce the importance of controlling the chemical composition of glycoside blends to minimize undesirable aftertastes and achieve sensory balance. The results provide valuable insights for the food industry to support sucrose replacement strategies in different products.
tese
Biological control of common bacterial blight and reduction of transmission of Xanthomonas phaseoli pv. phaseoli to bean seeds
(Universidade Federal de Lavras, 2026-06-29) Gontijo, Guilherme Foschetti; Souza, Ricardo Magela de; Siqueira, Carolina da Silva; Siqueira, Carolina da Silva; Carvalho, Claudine Marcia; Machado, José da Cruz; Botelho, Deila Magna dos Santos
Common bacterial blight (CBC), caused by Xanthomonas phaseoli pv. phaseoli (Xpp), is one of the most important diseases affecting common bean crops, with its incidence resulting in annual yield losses. The primary means of pathogen dissemination is through the association of the bacterium with bean seeds, which transmit the pathogen to emerging plants and subsequently lead to disease development. The limited availability of effective control methods highlights the need to develop alternative strategies integrated into crop management systems. Biological control of plant diseases is an efficient method and has shown positive results against several phytopathogens in bean cultivation. Therefore, the objective of this study was to evaluate the effects of spraying endophytic bacteria on bean plants for the control of common bacterial blight. Bacterial isolates obtained from bean seeds and one isolate from tomato (UFLA22) were selected for use as biological control agents, along with an Xpp isolate also obtained from bean seeds. Experiments were conducted under laboratory and greenhouse conditions in a randomized block design. The antibiosis effect of the selected bacteria against the Xpp isolate, disease severity, plant height and weight, phenolic compound contents, and phenylalanine ammonia-lyase (PAL) activity after treatment were evaluated. All evaluated isolates inhibited Xpp growth in vitro. Isolates G35, G37, G40, and UFLA22 showed greater effectiveness in controlling common bacterial blight, with isolate UFLA22 being the most efficient. Isolates G33, and UFLA22 contributed to the increase of plant weight in diseased plants, exceeding the values observed in the inoculated control and in the healthy control. Phenolic compound contents and PAL activity were higher in treatments with isolates G40 and UFLA22 compared with the inoculated control. Isolates G40 and UFLA22 reduced the transmission of Xpp to bean seeds, being recovered from seeds when applied on R6. These results demonstrate that bacteria isolated from bean seeds may be effective in controlling CBC.
dissertação
Pegada de carbono e custeio do ciclo de vida na produção de café orgânico
(Universidade Federal de Lavras, 2026-06-29) Hamasaki, Paulo Seiiti Araújo; Terra, Marcela de Castro Nunes Santos; https://orcid.org/0000-0003-4646-2414; Chiodi, Rafael Eduardo; https://orcid.org/0000-0002-5462-6856; Teixeira, Elaine Cristina; https://orcid.org/0000-0001-5215-8238
The growing demand for sustainable agricultural systems has driven the development of tools capable of simultaneously assessing the environmental and economic performance of productive activities. In this context, organic coffee farming stands out as a potential alternative for reducing environmental impacts, adding value to agricultural products, and promoting sustainability in rural areas. This study aimed to evaluate the environmental and economic performance of organic coffee production (Coffea arabica L.) in the municipality of Maria da Fé, Minas Gerais, Brazil, through the preparation of a greenhouse gas (GHG) inventory, carbon footprint quantification, and the application of the Life Cycle Costing (LCC) methodology. The research was conducted on a certified organic and specialty coffee farm covering 2 hectares during the period from 2020 to 2025. The emissions inventory was developed using the GHG Protocol Coffee Production Tool, specifically designed for Brazilian coffee-growing conditions, considering direct and indirect emissions as well as carbon removal processes associated with plant biomass and land-use change. The economic assessment was carried out using Life Cycle Costing, employing financial indicators such as Net Present Value (NPV), Internal Rate of Return (IRR), and Discounted Payback Period. The results showed cumulative emissions of 19.92 t CO₂e over the evaluated period, corresponding to a gross carbon footprint of 1.92 kg CO₂e kg⁻¹ of coffee produced. However, when carbon removals resulting from biomass growth and the conversion of a former pasture area into a coffee plantation were considered, a cumulative net balance of -99.54 t CO₂e was observed, resulting in a net carbon footprint of -9.59 kg CO₂e kg⁻¹ of coffee. These findings demonstrate that the production system acted as a net carbon sink throughout the entire study period. From an economic perspective, the activity presented a Net Present Value of R$ 9,876.45, an Internal Rate of Return of 17.61% per year, and a Discounted Payback Period of 3.45 years, indicating financial viability despite the substantial initial investments required for plantation establishment and maintenance of organic certification. The integration of environmental and economic indicators demonstrated that organic coffee production can reconcile economic profitability with climate change mitigation, reinforcing its potential as a sustainable development strategy for Brazilian coffee farming. In addition to contributing to income generation and strengthening family farming, the results provide technical support for farmers, cooperatives, and policymakers involved in lowcarbon agriculture initiatives. The study expands current knowledge regarding the relationship between environmental sustainability and economic viability in coffee production, serving as a reference for future research and for the development of more resilient, competitive, and environmentally responsible production systems aligned with contemporary sustainability challenges.