http://repositorio.ufc.br/handle/riufc/54 2026-06-12T17:03:26Z http://repositorio.ufc.br/handle/riufc/85870 Título: Análise filogenética de isolados de Fusarium spp. agentes etiológicos da podridão da coroa em banana no Brasil Autor(es): Araujo, Leticia Rejane Lima Abstract: Banana (Musa spp.) belongs to the order Zingiberales, family Musaceae, and genus Musa. Originating from Southeast Asia and the Western Pacific, it has been introduced and widely cultivated in various regions of the world. Currently, it is the most produced fruit globally and the second most consumed, with Brazil ranking as the sixth largest producer. In Brazil, production reached approximately 6.9 million tons in 2024, with a strong emphasis on domestic consumption.Despite its economic importance, banana production faces challenges due to postharvest diseases, which affect fruit quality and lead to economic losses. Crown rot has been identified as one of the main diseases, caused by a complex of fungi, particularly Colletotrichum spp., Lasiodiplodia spp., Verticillium spp., and especially Fusarium spp. The disease typically manifests after fruit ripening, compromising its marketability. Therefore, the objective of this study was to perform molecular, morphological, and pathogenic characterization of Fusarium spp. isolates obtained from different banana cultivars in Brazil. A total of 40 Fusarium spp. isolates were collected from asymptomatic banana hands in 10 municipalities across the states of Ceará, Goiás, and Rio Grande do Norte, Brazil. These isolates were georeferenced and obtained from the cultivars Prata, Nanica, and Grand Naine. The isolates were subjected to morphological analysis, molecular characterization (using TEF1 and RPB2 genes), and pathogenicity tests. Phylogenetic analysis revealed significant species diversity within the following complexes: Fusarium fujikuroi Species Complex (FFSC), Fusarium incarnatum-equiseti Species Complex (FIESC), and Fusarium oxysporum Species Complex (FOSC). Within the FFSC, Fusarium musae was the most prevalent species; within the FIESC, Fusarium sulawesiense and Fusarium pernambucanum were prominent. In the FOSC, Fusarium triseptatum and Fusarium fabacearum were identified. Pathogenicity tests demonstrated that all isolates were capable of causing disease symptoms, with F. triseptatum (FOSC) being the most aggressive. These results highlight the complexity of banana crown rot, with multiple Fusarium species contributing to the disease. Tipo: Dissertação 2025-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/85568 Título: Alterações fisiológicas em plantas de coqueiro provocadas por Raoiella indica Hirst e a endoterapia como alternativa para seu controle Autor(es): Oliveira, Felipe Silva Abstract: Raoiella indica is an exotic and invasive mite species in the Americas. Knowledge about the basic (ecological) and applied (management) aspects of this species is still scarce. This is the first study to investigate not only the use of endotherapy to control R. indica in coconut plants, but also the potential physiological changes in the host plant due to R. indica attack. Coconut plants were subjected to three distinct treatments: control (no phytosanitary treatment), endotherapy (abamectin injection into the plant stem), and spraying (abamectin spraying directed at the leaflets). Plant leaflets were evaluated for R. indica infestation (number of motile forms/leaflet) monthly and until the infestation level was reestablished during the endotherapy treatment. Additionally, physiological parameters were measured on the leaflets collected in each treatment at two different time points (one in the rainy season and the other in the dry season). The results of this study demonstrated that: (i) endotherapy with the acaricide abamectin was effective in reducing R. indica populations; (ii) the interval between abamectin acaricide applications via endotherapy can reach 10 months (300 days); (iii) abamectin applications every 2 months via spraying of the plant canopy can contribute to reducing R. indica populations; (iv) the main physiological changes in coconut plants mediated by R. indica attack are observed in the net photosynthetic rate, stomatal conductance, and transpiration; and (v) physiological changes vary according to environmental conditions (rainy and dry seasons). Tipo: Dissertação 2023-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/84600 Título: Comportamento antipredação de Tetranychus urticae Koch (Trombidiformes: Tetranychidae) em melão Autor(es): Carvalho, Yago Lourenço de Abstract: Predator-prey interactions constitute one of the main mechanisms shaping population dynamics and prey behavior. Under predation risk, many prey species may develop antipredator strategies, including behavioral changes such as refuge use and shifts in oviposition. For small arthropods, structures such as leaf trichomes may be used as resources to avoid predation at low energetic cost. In plants such as melon (Cucumis melo L.), a high density of trichomes may act both as a barrier to predators and as a refuge for phytophagous organisms. Accordingly, the objectives of this study were to evaluate: 1) Does Tetranychus urticae Koch use melon leaf trichomes as an antipredator strategy? 2) Does the response of T. urticae vary under different levels of predation risk? 3) Does the response of T. urticae vary when exposed to the predators Neoseiulus idaeus Denmark & Muma (specialist) or Neoseiulus barkeri Hughes (generalist), and does predator identity modulate the response of T. urticae? 4) Do trichomes interfere with predator performance? To assess the oviposition behavior of T. urticae, female mites were placed on melon leaves under different predation-risk scenarios: control (no exposure to predators), high risk (direct exposure to the predatory mite), medium risk (indirect exposure to the predator), and low risk (exposure to simulated predation using crushed eggs). Antipredator responses were evaluated based on the daily oviposition rate and the oviposition site (trichomes, glabrous areas, and webbing). To evaluate the effect of trichomes on predator performance, prey encounter time and egg consumption were assessed on leaves with high (melon leaves) and low (jack bean leaves) trichome density. The results showed that T. urticae is able to alter its reproductive behavior in response to predation risk. Significant changes were observed following exposure to predators or their cues, with a greater reduction in oviposition rate when exposed to the specialist predator. An effect on the pattern of oviposition site selection was observed, with increased oviposition on webbing rather than on trichomes, indicating that trichomes are not used as oviposition refuges. In the assessment of predator performance, higher trichome density increased prey encounter time for N. idaeus and reduced egg consumption for both predators. Overall, the results indicate that T. urticae does not use melon leaf trichomes as an anti-predator strategy for egg laying, instead preferring oviposition on webbing when exposed to predation risk. However, melon trichomes appear to influence predator foraging behavior, reducing the efficiency of N. barkeri and N. idaeus in the predation of T. urticae eggs. Tipo: Dissertação 2025-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/84439 Título: Priming e a tolerância do sorgo granífero ao estresse hídrico e salino Autor(es): Pinheiro, Charles Lobo Abstract: Drought and salinity are the main abiotic factors, which have limited agricultural production worldwide, and can cause great losses mainly in the most critical stages of the crop, such as germination and initial growth. However, investing in strategies such as the use of more tolerant species, such as sorghum, can ensure greater stability of agricultural production. In addition, seed priming, with GA3, may potentiate the tolerance of these genotypes, reducing the damage caused by stresses during germination and establishment of the crop. The objective of this research was to analyze the ability of three sorghum genotypes to germinate and grow under water and saline stress conditions, as well as to evaluate the efficiency of the hormonal priming, with GA3, in improving the tolerance of the genotypes and less sensitive to stress. The research was carried out in two stages, in the first the three genotypes were submitted to 5 levels of water stress (0,0; -0,3; -0,6; -0,9 and -1,2 MPa) and 7 Salinity levels (0.0, 4.0, 8.0, 12.0, 16.0, 20.0 and 24 dS m-1); In the second stage, the seeds of the genotypes, more tolerant and less tolerant, were treated by hormonal priming, by soaking the seeds for 2 hours in GA3 solutions at concentrations of 0,0; 50; 75 and 100 mg/L, with a constant temperature of 25°C, and in a dark environment, and then dried for 24 hours at 30°C. Under the conditions controlling water and saline stress the genotype BRS 330 was the most tolerant, and the L-20 the most sensitive genotypes during the initial phase of the culture. Under the conditions controlling water and saline stress the genotype BRS 330 was the most tolerant, and the L-20 the most sensitive genotypes during the initial phase of the culture, and priming with GA3, at 100 mg/L concentration, improved tolerance of sorghum during the initial phase, water and saline stress conditions, especially the more tolerant genotype. Therefore, the combination of strategies such as the use of more tolerant species or genotypes, and priming with GA3 are efficient in reducing the damages caused by water and saline stresses during germination and seedling growth. Tipo: Dissertação 2017-01-01T00:00:00Z