Anthracnose intensity and physical and chemical characteristics of ‘Prata anã’ banana under different nitrogen doses

Abstract The balanced supply of nitrogen to fruit trees leads to higher fruit quality and reduced incidence of diseases. The aim of this study was to evaluate anthracnose intensity and the physical and chemical characteristics of ‘Prata Anã’ banana under different nitrogen doses. Regarding anthracnose intensity, N doses of 150, 200, 250, 400 and 600 kg ha-1 were used. The Area Under the Incidence Progress (AUIPC) and Severity Curves (AUSPC) were evaluated. The physical and chemical characteristics were: fruit and pulp mass; soluble solids; starch; total, reducing and non-reducing sugars; coloration and nutrient concentration in peel, evaluated every three days for 15 days. Plants fertilized with N doses of 200, 250 and 400 kg.ha-1 had lower AUIPC values and the application of 250 kg.ha-1 reduced AUSPC in fruits inoculated with C. musae. N, P and K increased in banana peel, fruit and pulp mass, soluble solids, starch, total sugars, reducing sugars, with increasing N doses. There was no difference in the contents of micronutrients in fruit peel. N dose of 600 kg.ha-1 reduced the shelf life of fruits and provided higher sugar content and higher disease severity.

摘要：为果树均衡供给氮肥可提升果实品质并降低病害发生率。本研究旨在评估不同施氮量下‘Prata Anã’香蕉的炭疽病发生强度及其理化特性。针对炭疽病发生强度，试验设置了150、200、250、400及600 kg·ha⁻¹共5个施氮梯度，测定了发病率进展曲线下面积（Area Under the Incidence Progress, AUIPC）与严重度曲线下面积（Area Under the Severity Progress Curves, AUSPC）。本次研究测定的理化特性指标包括：果实与果肉质量、可溶性固形物含量、淀粉含量、总糖、还原糖与非还原糖含量、果皮色泽及果皮养分浓度，测定周期为每3天1次，连续开展15天。结果显示，施用200、250及400 kg·ha⁻¹氮肥的植株，其果实的AUIPC值更低；其中施用250 kg·ha⁻¹氮肥可降低接种胶孢炭疽菌（Colletotrichum musae, C. musae）的果实的AUSPC值。随着施氮量提升，香蕉果皮、果实及果肉中的氮、磷、钾含量，果实与果肉质量、可溶性固形物、淀粉、总糖及还原糖含量均显著升高。香蕉果皮中的微量营养元素含量无显著差异。当施氮量为600 kg·ha⁻¹时，会缩短果实货架期，同时提升果实糖含量与病害严重度。