Intensidade da seca da mangueira em mudas submetidas a diferentes níveis de salinidade

• Autor(a) principal: Murta, Hiunes Mansur
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4414
• topic: Ceratocystis fimbriata; Epidemologia; Manejo; Fisiologia; Ceratocystis fimbriata; Epidemiology; Management; Physiology; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::FITOPATOLOGIA

Mango wilt, caused by C. fimbriata, is a limiting factor to mango production in Oman, is here salinized soils predominant. As effect of salinity on disease intensity is unknown, we aimed to evaluate the effect of salinity on the disease in mango plants with different combinations rootstock x graft. Two experiments were carried out, E1 and E2. In both, we used five concentrations of NaCl (0, 15, 30, 45 and 60 mmol L-1) and three inoculation treatments (plants either uninoculated, inoculated in the rootstock, or inoculated in the graft). In E1, three cultivars were used as rootstocks ('Espada', 'Imbu' and 'Uba') and one as graft ('Haden'). In E2, Uba was used as rootstock and three cultivars were used as graft ('Palmer', 'Haden' and 'Tommy Atkins'). C. fimbriata was inoculated 10 cm above (graft inoculation) or below (rootstock inoculation) the grafting. The seedlings were kept in Hoagland solution in aerated hydroponic system. We run each experiment twice, each one in a completely randomized factorial design with four replicates (onde plant = one experimental unit). We assessed the time for the plants to wilt and die, length of lesions, and calculated the area under the disease progress curve and the rate of disease progression. At 0 and 90 days of exposure of the plant to the salt stress, we evaluated: plant height and diameter, and at 90 days the chlorophyll fluorescence and stomatal conductance. At the end of the experiments, we also determined: dry mass of the root and leaves, total dry matter, and content of N, P, K, Ca, Mg, Na and Cl in the root, stem, and leaves. The mango wilt intensity in the plants was greater when C. fimbriata was inoculated in the rootstock. There was a decrease in height, diameter, dry matter, and N, P, K, Ca and Mg with increasing concentrations of NaCl. In all cultivars evaluated disease symptoms were observed. In all situations in which Uba' was used as rootstock and 'Tommy Atkins' as graft, we detected lesser sensibility to salt stress and susceptibility to mango wilt.