Alterações morfofisiológicas em plantas de melão e pepino, qualidade de frutos de melão e proteção de pepino contra Colletotrichum lagenarium, ocasionadas pelo paclobutrazol

• Autor(a) principal: Silva, Katchen Julliany Pereira
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4544
• topic: Melão; Pepino; Doenças e pragas; Melon; Cucumber; Diseases and pests; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA

Despite the potential of Paclobutrazol (PBZ) as a plant growth regulator and elicitor agent, researches about its use in cucurbits are still scarce. This study was divided in 4 experiments and aimed: to evaluate the PBZ effects on development of melon plants; to evaluate the PBZ effect on morphophysiological features and quality of melon fruits; to detect and quantify PBZ residue in melon pulp using High Performance Liquid Chromatography (HPLC); and finally, verify morphophysiological changes and its elicitor potential against C. lagenarium in cucumber plants, causal agent of anthracnose in this culture. At first, treatments consisted of 11 PBZ doses (2, 4, 8, 12, 16, 20, 30, 40, 50, 60 and 70 mg PBZ plant-1) and the control (untreated plants). In the second experiment 4 PBZ doses were used (0.4, 0.8, 1.2 and 1.6 mg PBZ plant-1) and the control. To the third experiment, 8 fruits per treatment were collected to detect and quantify PBZ residues on melon pulp. In the fourth experiment, two C. lagenarium isolates (CLKJ11 and CLKJ25) were tested in 7 treatments: pure BDA medium (control) and plus with PBZ concentrations (50, 100, 200 and 400 mg L-1), FTT (Tebuconazole + Trifloxystrobin) (100 mg L-1) and FTB (Tebuconazole) (200 mg L-1) to the bioassay. To evaluate the morphophysiological changes and elicitor potential of PBZ, cucumber plants were treated with 4 PBZ doses (50, 100, 200 and 400 mg PBZ plant-1) and its leaves inoculated with suspension of isolate CLKJ25 at concentration of 1x10-8 conidia mL-1. PBZ is extremely efficient in reducing the size of melon and cucumber plants proving to be an effective alternative for management in green house crop. In addition, PBZ did not affect the productivity, appearance and quality attributes of melon fruits and no residue was found in melon pulp. The PBZ also proved to be effective in inhibiting the C. lagenarium mycelial growth and in the reduction of lesioned leaf area by this pathogen. Even so, this phytoregulator can not be considered a plant resistance inducer due to the toxic effect on the tested pathogen.