Qualidade pós-colheita de tubérculos de cultivares de batata influenciada por doses de nitrogênio

• Autor(a) principal: Braun, Heder
• Data de Publicação: 2007
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4455
• topic: Batata; Qualidade; Nitrogênio; Solanum tuberosum; Potato; Quality; Nitrogen; Solanum tuberosum; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA

The objective of this work was to determine the effect of nitrogen (N) rates on characteristics related to tuber post- harvest quality of potato cultivars. Four experiments were set up in 2006 fall/winter period in the Federal University of Viçosa. The soil was a typic Hapludult soil. Ágata, Asterix, Atlantic and Monalisa cultivars were tested in each experiment, with 0, 50, 100, 200 and 300 kg ha-1 of N as ammonium sulfate pre-planting applied. Each experiment was arranged in a randomized block design, with four repetitions. After harvest, the commercial tubers were left on the soil surface for two hours for periderm drying, then taken to the laboratory, classified, counted and weighed. Potato tubers were analyzed for: pH, titrable acidity, total soluble solids (ºBrix), content of total soluble sugar, reducing sugars and starch, percent difference between fresh mass of tubers stored under ambient conditions and cold chamber at 5 ºC; greening assessed by scoring scale and SPAD index on the periderm of washed and non-washed tubers; sprouted buds number in non dormant tubers; content and accumulation of dry mass and nutrients in tubers. For all cultivars, effect on dry mass accumulation; greening of washed tubers determined by SPAD-502; content of total soluble solids (ºBrix); of total N content and, accumulation of total N, P and Mn. There was no N effect on of dry mass and starch contents; pH; number of sprouted buds in washed and non- washed tubers, occurrence of hollow heart; P, K, Ca, Mg, S, Fe and Zn contents and Zn accumulation. Depending uppon the cultivar, there was N rate effects on the following variables: class II tubers number; class II and III tuber mass; greening of non-washed tubers determined by SPAD-502; greening of washed and non-washed tubers assessed by scoring scale; percent difference between fresh mass of tubers stored under ambient conditions and cold chamber; titrable acidity; contents of total soluble sugar, reducing sugars, Cu and Mn; accumulation of K, Ca, Mg, S, Cu, and Fe in tubers. The total N content in tuber dry mass was 1.44, 1.63, 1.38 and 1.35 dag kg-1 leading to the accumulation of 87, 98, 123 and 64 kg ha-1 of N at the N rate associated with the maximum commercial tuber yield for Ágata, Asterix, Atlantic and Monalisa, respectively.