Intensidade de antracnose e características física e química em banana 'Prata Anã' sob diferentes doses de nitrogênio

Abstract

Banana is the most cultivated tropical fruit tree in the world. In Brazil several post-harvest diseases affect this crop, among them anthracnose caused by Colletotrichum musae. Among cultural control methods, nutrient management can be an effective pathogen control. This study aimed at evaluating the intensity of anthracnose and the physico-chemical characteristics in dwarf silver banana under different doses of nitrogen (N). A randomized-complete block design with five nitrogen treatments ( T1 = 150;T2=200;T3= 250 T4 = 400 ; T5 = 600 kg ha ⎺¹) and four replications was used. The dose of 250 kg ha ⎺¹ of N was used as reference, since it is employed by the banana growers in the region of the study, north of Minas Gerais, Brazil. The Area Under the Incidence Progress Curve (AUIPC) and the Area Under the Severity Progress Curve (AUSPC) were calculated every three days for 12 days, and the fruit physico-chemical characteristics were evaluated every three days for 15 days. Macro and micronutrient concentration in banana skin was evaluated. Plants fertilized with doses of 200, 250 and 400 kg ha⎺¹of N presented the lowest AUIPC values in the field. Plants fertilized with doses of 200 and 250 kg ha⎺¹ of N, inoculated with conidia of C. musae, presented the lowest AUIPC values in laboratory. The lowest AUSPC value in plants inoculated with conidia of C. musae in laboratory occurred with the dose of 250 kg ha⎺¹ of N. The dose of 150 kg ha⎺¹ of N presented the highest disease progression for both incidence and severity. As fruits were maturing, there was an increased loss of mass, pulp, titratable acidity, chromaticity, brightness, soluble solids, total sugars, reducing sugars, non-reducing sugars, as well as a reduced pH, fruit skin thickness, firmness, hue angle and starch. Plants fertilized with doses of 150, 200, 250 and 400 kg ha⎺¹ of N yielded fruits with the best consumer acceptance and plants fertilized with the dose of 600 kg ha⎺¹ showed the fastest maturation. The contents of N, P and K on banana skin increased with the increasing doses of N.Banana is the most cultivated tropical fruit tree in the world. In Brazil several post-harvest diseases affect this crop, among them anthracnose caused by Colletotrichum musae. Among cultural control methods, nutrient management can be an effective pathogen control. This study aimed at evaluating the intensity of anthracnose and the physico-chemical characteristics in dwarf silver banana under different doses of nitrogen (N). A randomized-complete block design with five nitrogen treatments ( T1 = 150;T2=200;T3= 250 T4 = 400 ; T5 = 600 kg ha ⎺¹) and four replications was used. The dose of 250 kg ha ⎺¹ of N was used as reference, since it is employed by the banana growers in the region of the study, north of Minas Gerais, Brazil. The Area Under the Incidence Progress Curve (AUIPC) and the Area Under the Severity Progress Curve (AUSPC) were calculated every three days for 12 days, and the fruit physico-chemical characteristics were evaluated every three days for 15 days. Macro and micronutrient concentration in banana skin was evaluated. Plants fertilized with doses of 200, 250 and 400 kg ha⎺¹of N presented the lowest AUIPC values in the field. Plants fertilized with doses of 200 and 250 kg ha⎺¹ of N, inoculated with conidia of C. musae, presented the lowest AUIPC values in laboratory. The lowest AUSPC value in plants inoculated with conidia of C. musae in laboratory occurred with the dose of 250 kg ha⎺¹ of N. The dose of 150 kg ha⎺¹ of N presented the highest disease progression for both incidence and severity. As fruits were maturing, there was an increased loss of mass, pulp, titratable acidity, chromaticity, brightness, soluble solids, total sugars, reducing sugars, non-reducing sugars, as well as a reduced pH, fruit skin thickness, firmness, hue angle and starch. Plants fertilized with doses of 150, 200, 250 and 400 kg ha⎺¹ of N yielded fruits with the best consumer acceptance and plants fertilized with the dose of 600 kg ha⎺¹ showed the fastest maturation. The contents of N, P and K on banana skin increased with the increasing doses of N.