Qualidade de sementes de Gossypium hirsutum L., submetidas a tratamentos alternativos

• Autor(a) principal: Silva, Edcarlos Camilo da
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFPB
• Texto Completo: https://repositorio.ufpb.br/jspui/handle/123456789/29627
• topic: F. oxysporum f. sp. vasinfectum; óleos essenciais; assepsia; inoculação de patógenos; CNPQ::CIENCIAS AGRARIAS

Cotton plants (Gossypium hirsutum L.) is infected by several diseases being mostly transmitted by seeds, resulting in significant production losses. In this sense, the objective was to determine the sanitary and physiological quality of cotton seeds, submitted to alternative treatments and the efficiency of different methods of inoculation of Fusarium oxysporum f. sp. vasinfectum in cotton seeds. The experiment was carried out at the Phytopathology Laboratory of the Agricultural Sciences Center, at the Federal University of Paraiba with seeds from two cotton cultivars produced in the municipality of Remígio, PB: BRS Rubi and BRS Aroeira. For first experiment, the seeds were submitted to aseptic treatments: control: sterile distilled water (SDW) for 3 min (T0); 1% NaClO for 3 min + triple rinse with SDW (T1); 2% NaClO for 1 minute + 1 rinse with SDW (T2); 70% alcohol for 30 seconds + triple rinse SDW + 0.5% NaClO for 1 minute + triple rinse with SDW (T3); dicarboximide fungicide (240 g 100 kg-1 seeds) (T4) and 70% alcohol for 30 seconds + 1% NaClO for 1 minute + 1 rinse with SDW for 1 minute (T5) then evaluated for sanity, germination and emergency. For the second experiment, the seeds were submitted to: control (SDW); fungicide dicarboximide (240 g 100 Kg-1 of seeds) and essential oils of Cymbopogon citratus, Foeniculum vulgare and basil Ocimum basilicum in concentrations of 0.5; 1.0; 1.5 and 2.0 μL mL-1, respectively. 200 seeds per treatment were used in the healthy test, distributed in twenty repetitions of ten seeds. In the germination and emergency tests 200 seeds were used, four replicates of 50 seeds per treatment. For the third experiment, the seeds were submitted to inoculation methods with mannitol (C6H14O6), sucrose (C12H22O11) and suspension of spores, at different times of exposure to the pathogen (0, 24, 48, 72 and 96 hours). The severity of the disease was evaluated daily, during 15 consecutive days, from the 10th day after inoculation on seedlings grown in polyethylene trays with commercial substrate. In the greenhouse, the final stand, incidence of symptomatic seedlings, disease index, infection and transmission rate, area under the disease progress curve, stem diameter, length and dry weight of shoots and roots were evaluated in cotton seedlings 25 days after sowing. In the seeds of the cultivar BRS Rubi and BRS Aroeira there is a higher incidence of Aspergillus sp., A. niger, Penicillium sp., Cladosporium sp. and Fusarium sp. Sanitizers treatments are indicated on cotton seeds to reduction fungi, without compromising their physiological quality. The treatments based on 1% NaClO for 3 min + triple rinse with SDW (T1) and 2% NaClO for 1 min + 1 rinse with SDW (T2) favor the percentage of germination in the BRS Rubi and seedling emergence in the BRS Aroeira. In the seeds of cultivar BRS Rubi there is a higher incidence of Aspergillus sp., Penicillium sp. and Trichoderma sp., while the highest percentages of Cladosporium sp., Fusarium sp. and A. niger are observed in the seeds of the cultivar BRS Aroeira. The essential oils of lemongrass, fennel and basil are efficient in reducing fungi in seeds of G. hirsutum from the cultivars BRS Rubi and BRS Aroeira. The oils of C. citratus, F. vulgare and O. basilicum positively influence the physiological quality of the seeds of the Rubi and negatively interfered in the seedling emergence and vigor percentages Aroeira. The methods of inoculation with mannitol, sucrose and spore suspension are efficient for inoculation of Fov on Gossypium hirsutum seeds. The inoculation of F. oxysporum f. sp. vasinfectum in culture medium modified with mannitol at 48 h and sucrose for 96 h allowed higher rates ofinfection and transmission for the cultivar BRS Rubi and with mannitol at 48 h in BRS Aroeira, but with less influence of the physiological seeds parameters.