https://ri.ufs.br/jspui/handle/riufs/7318 Sat, 29 Aug 2026 07:15:55 GMT 2026-08-29T07:15:55Z http://ri.ufs.br:80/retrieve/6a0d7827-1bbc-4e0c-b467-7d5dcee6ee1e/a15346f0-3c11-45f7-997f-dac4b3269660.jfif https://ri.ufs.br/jspui/handle/riufs/7318 https://ri.ufs.br/jspui/handle/riufs/25924 Título: Enviromics e modelagem preditiva aplicadas ao melhoramento de milho (Zea mays L.) no semiárido brasileiro Autor(es): 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. Tue, 14 Jul 2026 00:00:00 GMT https://ri.ufs.br/jspui/handle/riufs/25924 2026-07-14T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/25921 Título: Filmes de partículas de óxido de cálcio e silício em campo e casa de vegetação, na avaliação de déficit hídrico e aprendizagem de máquinas na predição da produtividade de abóbora “mini jack” Autor(es): Graça, Genilza Almeida da Abstract: Climate change has intensified the frequency and severity of drought periods, increasing risks to agricultural production and the need for strategies capable of enhancing crop tolerance to water deficit. In this context, calcium oxide (CaO)-based particle films and silicon (Si) have the potential to modulate physiological responses and alleviate the effects of stress, while machine learning enables the integration of biological and agronomic information for predicting crop productivity. This study evaluated the effects of CaO and Si on mitigating water deficit in ‘Mini Jack’ pumpkin (Cucurbita moschata) plants, considering physiological, biochemical, growth, and productivity responses, as well as the potential of machine learning algorithms for productivity prediction. The study was structured into three articles. In the first article, different CaO concentrations (0, 2.5, 5, and 7.5%) were evaluated under two irrigation regimes (66 and 100% of crop water requirements). CaO application modulated photochemical functioning and productivity performance, with the 5% concentration promoting electron transport, preserving photochemical efficiency, and improving yield. In contrast, the 7.5% concentration resulted in less favorable responses, highlighting the importance of optimizing particle film concentration. In the second article, the individual and combined applications of Si and CaO were evaluated under different water regimes. Water deficit impaired plant growth and altered photosynthetic pigments, the chlorophyll a fluorescence transient, and osmotic and antioxidant responses. CaO alone contributed to maintaining leaf area under water deficit, whereas the Si + CaO combination increased chlorophyll indices, preserved photochemical functioning, and reduced proline accumulation As well as CAT and APX activities, indicating lower oxidative stress and a predominantly preventive strategy for protecting the photosynthetic apparatus. In the third article, Linear Regression, Random Forest, and SMOreg algorithms were evaluated for productivity prediction using progressively integrated datasets comprising pigments, OJIP parameters, biometric traits, and management variables. Pigments alone showed low predictive capacity, whereas the incorporation of OJIP parameters improved model performance, with Random Forest showing the best results. The integration of photochemical, pigment-related, and biometric information provided the highest predictive performance, with SMOreg outperforming the other algorithms, demonstrating that biological complementarity among predictors was critical for accurately representing productivity. Overall, the results demonstrate that CaO and its combination with Si are promising strategies for modulating the responses of ‘Mini Jack’ pumpkin plants to water deficit, while the integration of plant ecophysiology and machine learning enhances the ability to relate crop management, photosynthetic functioning, growth, and productivity. Fri, 24 Jul 2026 00:00:00 GMT https://ri.ufs.br/jspui/handle/riufs/25921 2026-07-24T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/25414 Título: O escurecimento e a cicatrização em inhame (Dioscorea spp.) minimamente processado é modulado pela região do tubérculo, aplicação de ácido ascórbico e temperatura de conservação Autor(es): Corrêa, Cristina Bani Abstract: Mechanical damage caused by peeling and cutting affects the biochemical and physiological processes of yam, triggering enzymatic oxidation and inducing rapid defense responses, such as the formation of structural barriers at the wound site. This study aims to investigate, in an integrated manner, the physiological, biochemical, and structural responses of minimally processed yam (Dioscorea cayenensis), evaluating the effects of tuber region, storage temperature, and ascorbic acid application on enzymatic browning and wound healing. Slices from the apical (AP), medial (ME), and distal (DI) regions were subjected to minimal processing, treated or not with ascorbic acid (1% w/v), and stored at 5 °C (browning) and at 5 and 20 °C (lignification). Quality and physicochemical parameters, phenolic metabolism, enzymatic activities (PPO, SOD, CAT, POD, and PAL), and lignin deposition were evaluated. Visual quality progressively declined during storage, with more pronounced losses in the apical region. ascorbic acid delayed browning and extended the acceptability of the medial and distal regions. Browning dynamics were modulated by polyphenol oxidase (PPO) activity, superoxide dismutase (SOD), and phenolic content, indicating that when enzymatic protection becomes insufficient, phenolic compounds act as non-enzymatic antioxidants. Chromatographic analysis revealed selective accumulation of hydroxycinnamic acids and flavonoids, indicating activation of the phenylpropanoid pathway in response to post-processing stress. The wound healing process was strongly influenced by temperature. At 5 °C, an antioxidant response predominated, with no detectable lignin deposition. In contrast, at 20 °C, increased activities of phenylalanine ammonia-lyase (PAL) and peroxidase (POD) were observed, along with lignin deposition, characterizing a structural response. Overall, the results demonstrate that the quality of minimally processed yam is determined by the interaction between tuber region, storage temperature, and ascorbic acid application, highlighting the multifactorial nature of oxidative stress regulation in minimally processed yam. Thu, 26 Feb 2026 00:00:00 GMT https://ri.ufs.br/jspui/handle/riufs/25414 2026-02-26T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/25370 Título: Prospecção, conservação, caracterização genética, química, morfoagronômica e sazonalidade em germoplasma de Croton blanchetianus Baill Autor(es): Costa, Rosemeire Santos Abstract: Croton blanchetianus Baill. is a medicinal and aromatic species native to the Caatinga biome, widely distributed in the Brazilian Northeast. It is notable for its high bioactive and apicultural potential, and it is listed by the Ministry of Environment as a priority species for the region due to its potential economic importance. Nevertheless, its natural occurrence area is frequently reduced, primarily due to anthropogenic interventions. In view of the imminent threats to the species’ genetic variability, the Federal University of Sergipe (UFS) studied natural populations and subsequently established a collection of C. blanchetianus in its Active Germplasm Bank (AGB) for Medicinal and Aromatic Plants at UFS. This initiative allows the development of strategies for conservation and sustainable use of the species. The present research aims to evaluate the genetic and chemical diversity of natural populations of C. blanchetianus from municipalities in the state of Sergipe, as well as to establish a collection, characterize the accessions morpho-agronomically, chemically, and seasonally, and assess the antioxidant activity of the accessions conserved in the AGB. In the first article, the genetic diversity and structure of six natural populations of C. blanchetianus from different municipalities in the state were evaluated, using ISSR markers. Low genetic variability among populations (6%) was observed, and it was not possible to differentiate genotypes according to their geographic origin. In the second article, the chemical diversity of the essential oil from 70 genotypes of C. blanchetianus, collected from six natural populations in Sergipe, was evaluated. The major compounds found were α-pinene (1.60–13.37%), limonene (0.30–17.54%), β-phellandrene (4.38–16.04%), 1,8-cineole (0.16–13.56%), (E)-caryophyllene (0.31–13.14%), germacrene D (0.33–10.60%), bicyclogermacrene (5.06–27.47%), and spathulenol (4.34–29.83%), highlighting the broad chemical diversity of the species. In the third article, the morphoagronomic and chemical diversity of 26 C. blanchetianus accessions was characterized and analyzed. High variability among accessions was observed for all evaluated morpho-agronomic descriptors, particularly plant height (87.00–236.50 cm), crown diameter (48.75–131.00 cm), leaf area (74.50–176.37 cm²), dry mass (83.17–333.00 g/plant), and essential oil content (0.60– 1.60%). Chemically, the accessions were mostly comprised of α-pinene (3.90–12.02%), limonene (0.88–10.72%), β-phellandrene (1.30–17.51%), 1,8-cineole (0.36–11.57%), (E)- caryophyllene (1.82–12.48%), germacrene D (0.38–10.12%), bicyclogermacrene (8.37– 29.13%), and spathulenol (5.57–28.04%). In the fourth article, the chemical profile of the essential oil from leaves and fruits of five accessions of C. blanchetianus was analyzed, revealing quantitative and qualitative differences between plant organs. Leaves had a predominance of sesquiterpenes (37.34–62.03%), whereas fruits had higher levels of monoterpenes (23.97–61.03%). The exclusive presence of myrtenyl acetate in fruit essential oil indicates its potential as a chemical marker. In the fifth article, the seasonal influence (three harvest periods) on agronomic variables, chemical composition, and antioxidant activity of essential oil from 26 accessions of C. blanchetianus was evaluated. Accessions CBL-403 and CBL-503 showed the highest oil content (1.93%), while CBL-503 (17.41 g/plant) and CBL507 (17.38 g/plant) exhibited the highest essential oil yields. Sesquiterpenes predominated in harvests 1 and 2 (59.02% and 62.01%, respectively), while monoterpenes increased in harvest 3 (40.01%). A high antioxidant potential was observed in accession CBL-301 (DPPH: 66.24%; ABTS: 92.51%). These results indicate that C. blanchetianus exhibits exploitable genetic, morpho-agronomic, and chemical variability, and that its essential oils show seasonal plasticity and antioxidant activity. Tue, 24 Feb 2026 00:00:00 GMT https://ri.ufs.br/jspui/handle/riufs/25370 2026-02-24T00:00:00Z