http://bdtd.unoeste.br:8080/jspui/handle/jspui/974 Doutorado em Agronomia 2026-03-19T04:49:22Z http://bdtd.unoeste.br:8080/jspui/handle/jspui/1739 Título: Atenuaçãodo estresse por calor em cultivares de algodoeiro pela aplicação de bioestimulante Autor: Arruda, Rúbia Nascimento Crivelli Primeiro orientador: Echer, Fábio Rafael Abstract: Cotton (Gossypium hirsutum L.) is essential for the textile industry, as well as for producing vegetable oil and animal feed. Brazil stands out as one of the leading producers, especially in tropical and subtropical regions, facing challenges due to adverse climatic variations. This study evaluated the productivity and fiber quality of different cotton cultivars treated with a biostimulant, aiming to mitigate thermal stress under high-temperature conditions in Mato Grosso. The experiment was conducted in a completely randomized design, with a subdivided scheme, comprising 12 treatments (combinations of cultivars and application of the biostimulant Megafol®) and four replicates, in the municipalities of Sorriso, Tabaporã, and Porto dos Gaúchos. The bio-stimulant was applied starting at the B1 stage (first floral bud appearance) at a dose of 250 mL/ha, with reapplications every 15 days, totaling six applications and an accumulated volume of 1.5 L/ha. Harvest evaluations included productive parameters and fiber quality attributes. The results indicated that genetic (cultivars) and environmental (cultivation sites) factors significantly influenced fiber productivity and quality. The cultivars DP 1949B3RF and FM 974GLT stood out in yield and fiber strength. Climatic conditions, especially temperature, directly affected cotton quality and performance, highlighting the need for adaptive strategies to mitigate thermal stress effects. It was concluded that there is a difference among cultivars regarding the yield and quality of cotton fiber in regions with high temperatures. The biostimulant showed a punctual and variable effect, with more consistent gains in Porto dos Gaúchos, especially in boll retention and seed formation, but it was not determinant for yield or fiber quality. Instituição: Universidade do Oeste Paulista Tipo do documento: Dissertação 2025-04-14T00:00:00Z http://bdtd.unoeste.br:8080/jspui/handle/jspui/1738 Título: Tratamento de sementes com o micronutriente níquel em plântulas de genótipos de soja Autor: Ferreira, Tainara Romani Primeiro orientador: Putti, Jéssica Pigatto Barcelos Abstract: Nutritional management practices are essential to ensure the sustainability of agriculture in tropical agroecosystems. In the soybean cultivation system, modern genotypes are becoming more productive and more demanding in terms of nutrients, thus, there is concern regarding the current fertilizer recommendation to attend the nutritional plants demand. In this scenario, the application of emerging nutrients, such as nickel (Ni), can play a key role. This micronutrient is a cofactor of the enzymes urease and hydrogenase, which act in the nitrogen (N) metabolism in plants, in addition to acting in seed germination. However, studies on methods of application for this micronutrient, especially seed treatment, are incipient. The research project aims to evaluate the response of seedlings of modern soybean genotypes to fertilization with micronutrient Ni supplied in seed treatment. Furthermore, the project aims to determine the agronomic dose of this micronutrient, as well as evaluate the symptoms of its phytotoxicity. In the laboratory, six doses of Ni will be tested on six modern genotypes cultivated in tropical conditions. For this purpose, the experiment was implemented on germination paper and conducted in an incubator under controlled conditions. After seven days of implantation, the height of the aerial part and length of the root system were evaluated. The experimental design was completely randomized, with four replicates. The results were analyzed by analysis of variance and, when significant were analyzed by regression test, and the means were compared by the Tukey test (p < 0.05).Cultivars respond differently to Ni doses. For responsive cultivars, Ni application via seed treatment was beneficial up to a Ni dose of 66 mg kg-1 of seeds. Ni doses greater than 66 mg kg-1 of seeds increased the percentages of seedlings abnormal and dead seeds, and reduced the root and shoot lengths of seedlings. Instituição: Universidade do Oeste Paulista Tipo do documento: Dissertação 2025-04-30T00:00:00Z http://bdtd.unoeste.br:8080/jspui/handle/jspui/1737 Título: Caracterização in silico e expressão de genes relacionados à prolina em feijão sob condições de estresse abióticos Autor: Oliveira, Jardel Primeiro orientador: Santos, Tiago Benedito Abstract: The common bean (Phaseolus vulgaris L.) is a crop of significant socioeconomic importance in Brazil, with production distributed across multiple states and seasonal cycles. This legume faces substantial soil and climate challenges, particularly abiotic stresses such as water deficit and salinity, which are limiting factors that reduce productivity. In this context, investigating contrasting genotypes for tolerance to these stresses, such as BAT 477 (tolerant) and Pérola (susceptible), represents a fundamental strategy for developing cultivars adapted to adverse environmental conditions. This study aimed to identify in silico and molecularly characterize the genes encoding the enzyme Δ¹-pyrroline-5-carboxylate synthetase (P5CS) and proline transporters (ProT) in P. vulgaris L., key components in the biosynthesis and translocation of proline, a compatible osmolyte with a crucial role in osmoregulation and cellular protection mechanisms under stress conditions. Through comparative genomic analyses, four P5CS genes and two ProT genes were identified in the common bean genome. The PvP5CS genes are distributed across chromosomes 1, 8 (containing two genes), and 10, indicating segmental duplication events throughout the species' evolutionary history. Phylogenetic analyses revealed significant genomic conservation among the P5CS genes of P. vulgaris L., Arabidopsis thaliana, and Oryza sativa. Regarding transcriptional profiles, PvP5CS3 showed the highest expression in all developed tissues, with particular abundance in nodules and roots, while PvP5CS2 exhibited reduced transcriptional levels in all vegetative organs. The ProT transporters, located on chromosomes 1 and 8, displayed preferential expression in floral tissues. Physiological assays under controlled conditions revealed contrasting patterns of proline accumulation between the tested genotypes in response to different stresses. Under saline stress (NaCl), the Pérola cultivar showed significantly higher proline accumulation compared to BAT 477, especially after prolonged exposure (12 days) and high NaCl concentrations, reaching approximately 55 μmol/g FW compared to only 7 μmol/g FW in BAT 477. Conversely, under osmotic stress induced by polyethylene glycol (PEG 6000), an opposite behavior was observed, with BAT 477 exhibiting greater proline accumulation capacity (8 μmol/g FW) compared to Pérola (3.5 μmol/g FW). Through in silico analyses, the expression profiles of these genes were identified in leaves of two bean genotypes (BAT 477 and Pérola) under saline and water stress. The genes PvP5CS1, PvP5CS3, and PvP5CS4 showed significantly lower gene expression in different vegetative tissues (in silico). Saline stress (osmotic), characterized by high salt concentrations, differs from water stress, which can result from both water deficiency and excess. These results suggest the existence of distinct regulatory mechanisms and genotype-specific responses in proline biosynthesis and transport under different abiotic stresses in P. vulgaris L.. The elucidation of these molecular mechanisms offers promising prospects for genetic improvement, supporting the development of cultivars with greater yield stability under adverse environmental conditions, thus contributing to food security and agricultural sustainability. Instituição: Universidade do Oeste Paulista Tipo do documento: Tese 2025-04-30T00:00:00Z http://bdtd.unoeste.br:8080/jspui/handle/jspui/1685 Título: Qualidade do solo e produtividade do algodoeiro afetados por plantas de cobertura e sistemas de preparo Autor: Rocha, Caroline Honorato Primeiro orientador: Echer, Fábio Rafael Abstract: The introduction of intensive production systems, such as cotton production, in sandy textured soils is increasing in Brazil; the type of management employed in these soils can negatively affect soil quality. However, the cultivation of cover crops can promote the increase of organic matter levels and improve the physical and biological conditions of these soils. The general objective of this study was to evaluate the production and fiber quality of cotton (Chapter 1) and the indicators of soil physical and biological quality (Chapter 2), carbon stock (C stock) and the chemical and physical fractions of organic C (Chapter 3) under the influence of cover crops millet and guinea grass in no-tillage (NT), minimum tillage (MT), fall tillage (FT) and Spring tillage (ST). The experiment was carried out during 2020/2021 and 2021/2022 seasons. The soil is classified as a Ferralsol with sandy texture. Cotton leaf carbohydrate content varied only in the 2020/2021 season, with higher values under ST, regardless of the cover crops. The ST+millet and MT+guinea grass resulted in a higher number of bolls and cotton yield in the 2021/2022 season. The MT+millet increased the micronaire, fiber length, and fiber strength, although all fiber quality parameters were suitable for commercialization. The NT, ST, and FT systems on millet improve the soil water storage capacity (cc/pt) showing compaction between 2,500 kPa and 3,200 kPa. The guinea grass under MT attenuated soil compaction by 23% and improved air storage capacity (par/pt), on the other hand, cc/pt increased under millet. The dehydrogenase activity was higher under NT with guinea grass. The microbial biomass carbon (Cmic) and soil respiration increased in NT+millet in 2020/2021 and decreased in the 2021/2022 season. In both seasons, millet under NT and MT increased the microbial biomass nitrogen (Nmic), while guinea grass favored Nmic increase under ST and FT. Glomalin content increased in NT+millet and MT+guinea grass in the 0.20-0.40 m layer. The C stock increased by 8% in NT, 5% under MT, and 5% in FT with millet compared to ST, respectively. The use of millet under NT increased stock organic carbon (SOC) in the 0.10-0.20 m layer compared to ST; however, in the 0.20-0.40 m layer, ST+millet increased SOC by 13% compared to the other tillage systems. In the 0.20-0.40 m layer, CAM increased under NT+guinea grass, but in the 0.40-0.60 m layer, millet was higher. The minerals-associated carbon (CAM) increased by 28% with millet at 0.10-0.20 m and by 17% with guinea grass compared to the FT in the same layer. The C lability increased by 32% with millet under MT in the 0.0-0.10 m, while C lability under guinea grass increased by 21% in the 0.10-0.20 m, respectively. When associated with guinea grass, MT increased the levels of fulvic acid (FA), humic acid (HA), HA:FA, humin, and humic substances (HS) at depth. Under NT+millet the AH and AH:AF was higher in the 0.0-0.10 m and 0.40-0.60 m. However, the NT+millet increased the humin and SH in the 0.40-0.60 m. The increase in the concentration of AH, AH:AF, and humin at 0.0-0.20 m was observed with millet in ST. Guinea grass under FT provided an increase in humin and SH in the 0.20-0.40 m between the cover crops. Our results suggest that millet under NT increases C stock at the surface of sandy soil and increased stable fraction of organic matter, improving soil physical and biological attributes. Even in a short planting window, millet with SF is a good option to increase cotton yield and surface C stock. Under better water availability, the MT with guinea grass improved the cotton yield, soil physical and biological attributes and C content. Instituição: Universidade do Oeste Paulista Tipo do documento: Tese 2024-11-29T00:00:00Z