https://repositorio.uema.br/jspui/handle/123456789/1900 Thu, 09 Jul 2026 04:09:54 GMT 2026-07-09T04:09:54Z http://repositorio.uema.br:80/jspui/retrieve/56fd114b-1023-44a0-a655-681aae84cc4b/AGROECOLOGIA UEMA 2.png https://repositorio.uema.br/jspui/handle/123456789/1900 https://repositorio.uema.br/jspui/handle/123456789/6269 Título: Efeitos dos fungos micorrízicos arbusculares sobre os parâmetros fisiológicos e de crescimento do milho sob déficit hídrico Abstact: the most significant for maize production, as it can cause physiological and growth changes in the plant. One strategy to mitigate the negative effects of WD is the use of arbuscular mycorrhizal fungi (AMF), which provide greater acclimation capacity to WD conditions by enabling increased water and nutrient absorption, such as phosphorus and nitrogen. The aim of this study was to evaluate the responses of chlorophyll a fluorescence characteristics and growth in maize plants subjected to water deficit and inoculated with arbuscular mycorrhizal fungi (AMF). The experiment was conducted in a greenhouse at the Postgraduate Program in Agroecology of the State University of Maranhão, located in São Luís/MA, from September to November 2023. The soil used was collected from a preserved vegetation area at the University's School Farm. Hybrid maize seeds AG1051, with an early cycle, were used. For soil inoculation in the AMF treatments, the species identified as Rhizoglomus clarum, acquired from the Embrapa Agrobiologia germplasm bank (Seropédica, RJ), was used. The experimental design was in randomized blocks, with a factorial scheme of 4 (sterile soil; natural soil; sterile soil + R. clarum; natural soil + R. clarum) x 2 (irrigated and water deficit), and four replications, totaling 32 experimental plots. Each plot was represented by a 20 L capacity pot, with one plant per pot. The experiment lasted for 51 days, until the V5-V6 stage. Meteorological variables were monitored throughout the day, and soil moisture was maintained at 90% of field capacity (FC) until 46 days after planting, when water restriction occurred, and stressed treatments were maintained at 20% of FC. According to the results, water deficit significantly reduced plant height, stem diameter, leaf area, specific leaf mass, fresh leaf and stem mass, as well as dry leaf, stem, and root mass. Therefore, inoculation with Rhizoglomus clarum in natural soil mitigated some of these negative effects, resulting in higher growth values compared to sterile soil under water stress. Under irrigated conditions, inoculation with R. clarum and natural soil had higher biomass compared to the sterile treatment. Inoculation with AMF had a significant impact on chlorophyll a fluorescence. Additionally, higher levels of carotenoids were observed, both under water deficit and irrigated conditions, compared to the sterile treatment. These results indicate that the application of AMF had a synergistic effect on maize plants, influencing physiological and biochemical processes. Tue, 26 Mar 2024 00:00:00 GMT https://repositorio.uema.br/jspui/handle/123456789/6269 2024-03-26T00:00:00Z https://repositorio.uema.br/jspui/handle/123456789/6241 Título: Efeitos de doses de molibdênio aplicadas na folhagem na produtividade e conteúdo de molibdênio na semente de feijão-caupi Abstact: Soils in Maranhão are generally sandy and acidic, conditions that favor the occurrence of plant nutrient deficiencies, particularly of phosphorus, nitrogen (N), and molybdenum (Mo). Consequently, cowpea grain yield in Maranhão is low relative to its productive potential. Adequate Mo supply to legumes reduces N deficiencies and the need for top-dressed mineral N fertilization. Therefore, our objective was to determine—under low-technology conditions in northern Maranhão—the foliar Mo rate applied at the cowpea V4 stage that maximizes yield, as well as the Mo rate required to raise seed Mo content to approximately 3.6 µg per seed (the level required for the crop in Minas Gerais). Field trials were conducted in 2022 in São Luís and Nina Rodrigues, Maranhão. No chemical fertilizer was applied at planting. Treatments were arranged in a 5 x 2 factorial design: foliar Mo rates applied at 25 days after emergence (DAE) in São Luís and 27 DAE in Nina Rodrigues (0, 50, 100, 200, or 300 g ha⁻¹) and top-dressed N rates (0 and 50 kg ha⁻¹). The cultivar BRS Guariba was used. The average number of nodules per plant was 6.5 in São Luís and 5.0 in Nina Rodrigues, and average yields were 465 kg ha⁻¹ in São Luís and 822 kg ha⁻¹ in Nina Rodrigues. In the absence of N, a foliar spray of 50 g ha⁻¹ of Mo increased leaf N content by 14.8% and grain yield by 50% compared to the zero-rate treatment. With N, Mo rates did not significantly influence these variables. There was no significant interaction between Mo rates and N rates regarding seed Mo content. However, the effect of the Mo rate factor on seed Mo content was highly significant. Foliar Mo applications increased seed Mo content by 140% to 614%. A seed Mo content of 3.54 µg was obtained with the 50 g ha⁻¹ Mo rate. Our results suggest that, for low-input cowpea cultivation, a foliar application of 50 g ha⁻¹ Mo is sufficient to maximize grain yield and produce Mo-enriched seeds. Tue, 26 Mar 2024 00:00:00 GMT https://repositorio.uema.br/jspui/handle/123456789/6241 2024-03-26T00:00:00Z https://repositorio.uema.br/jspui/handle/123456789/6239 Título: Espécies e acessos de Jurubeba (Solanum spp.) como porta-enxertos para o tomateiro e fonte de resistência a patógenos de solo Abstact: Tomato cultivation is highly significant for Brazilian society, both economically and in terms of nutrition and social impact. In the state of Maranhão, tomato plants find favorable conditions for development; however, challenges related to soilborne diseases such as bacterial wilt and Fusarium wilt require sustainable agricultural practices and technological innovations to ensure the continuity and efficiency of production. This study aimed to evaluate species/accessions of Solanum spp. from Maranhão for resistance/tolerance to bacterial wilt and Fusarium wilt and assess their potential as rootstocks for Santa Clara and cherry tomatoes. Additionally, this research sought to collect and enrich the "Jurubeba Bank (Solanum spp.)" at the UEMA School Farm. To analyze resistance and tolerance to Ralstonia solanacearum and Fusarium oxysporum f. sp. lycopersici, the experiment was conducted in a greenhouse using a completely randomized design (CRD) with 17 jurubeba accessions and four replications. Subsequently, four resistant varieties were selected for grafting (Bachicha – BQ, Red Jurubeba – JV, Peito de Moça – PM, and Juá) onto cherry tomato (S. lycopersicum var. cerasiforme, cv. Carolina) and Santa Clara tomato (S. lycopersicum, cv. Santa Clara), applying a factorial 5×4+2 scheme in a randomized block design (RBD). Seedlings showing symptoms were collected and sent for laboratory analysis to confirm the presence of the pathogens. The results confirmed that all Solanum spp. species/accessions, when inoculated with R. solanacearum and F. oxysporum f. sp. lycopersici, exhibited resistance to these pathogens. It was also observed that treatments with cherry and Santa Clara tomatoes did not show significant differences in height, leaf number, or compatibility index. However, in cherry tomato, the mortality rate was lower than in Santa Clara. It was concluded that Solanum spp. species are resistant to R. solanacearum and F. oxysporum f. sp. lycopersici, and that cherry tomato, when combined with different jurubeba rootstocks, performs better than Santa Clara in terms of grafting success and mortality rate. Mon, 19 Aug 2024 00:00:00 GMT https://repositorio.uema.br/jspui/handle/123456789/6239 2024-08-19T00:00:00Z https://repositorio.uema.br/jspui/handle/123456789/6238 Título: Quantificação espaço-temporal da fragmentação florestal na Amazônia e seu impacto nos estoques de carbono Abstact: Between 1990 and 2021, the International Amazon lost 672,295 km² of forest cover. This study analyzed the impacts of forest fragmentation during this period, based on seven morphological landscape classes: Core, Edge, Bridge, Loop, Branch, Islet, and Perforation. The MSPA model and Sentinel-2 imagery were used to classify and quantify structural connectivity, estimating carbon stocks from aerial biomass data. CO₂ emission estimates were obtained based on recognized conversion factors. Statistical analysis showed significant differences between classes, with emphasis on the reduction of Core areas, the main carbon reservoirs. French Guiana maintained 74.22% of the forest in Core state; Bolivia, 27.06%; and Brazil, 43.29% of the remaining forest fragmented. The most isolated areas had lower biomass density, indicating high vulnerability to degradation. In total, estimated emissions resulting from fragmentation amounted to 9.48 Pg of CO₂, equivalent to 31.61% of total emissions from deforestation during the period. The data show that forest fragmentation contributes significantly to the increase in emissions and reinforces the importance of maintaining large continuous blocks of vegetation for the integrity of ecosystems. Tue, 27 May 2025 00:00:00 GMT https://repositorio.uema.br/jspui/handle/123456789/6238 2025-05-27T00:00:00Z