Efeito da poda antecipada e regime de irrigação nos teores de açúcares em uvas 'Niágara Rosada' / Effect of antecipated pruning and irrigation regime on the sugar contents in 'Niágara Rosada' grapes

RESUMO

O experimento foi conduzido em um pomar comercial, localizado no município de Lavras - MG, objetivando-se com este trabalho avaliar o efeito da poda antecipada no teor de açúcares da uva 'Niagara Rosada' (Vitis labrusca L.). Os tratamentos empregados corresponderam à diferentes épocas de poda de frutificação, sendo realizada, respectivamente, em 03/05/2004, 17/05/2004, 31/05/2004, 15/06/2004, 29/06/2004, 13/07/2004 (podas antecipadas), 20/07/2004 e 03/08/2004 (podas tradicionais, com e sem regime de irrigação). Para avaliar a qualidade das uvas 'Niágara Rosada' quanto ao teor de açúcares realizaram-se, as seguintes análises: açúcares totais, açúcares redutores (glicose e frutose) e relação frutose/glicose. Para execução das análises foram retiradas as sementes e trituradas as bagas com casca e polpa. Verificou-se que a qualidade dos frutos colhidos fora do pico de produção, ou seja, poda antecipada, atendem aos padrões de qualidade exigidos pela legislação e que a irrigação compromete o teor de açúcares na uva, reduzindo os mesmos.

ABSTRACT

The experiment was conducted at a commercial orchard situated in the municipality of Lavras - MG, with the objective of evaluating the effect of anticipated pruning on the sugar content of 'Niagara Rosada' grape (Vitis labrusca L.). The treatments employed corresponded to different times of pruning for fructification, being performed on May 5th 2004, , May 17th 2004, May 3rd 2004, June 15th 2004, June 29th 2004, July 13th 2004 (for anticipated prunings), July 20th 2004 and August 3rd 2004 respectively, for traditional prunings, with and without irrigation regime. To evaluate the quality of 'Niágara Rosada' grapes regarding the sugar content, the following analyses were accomplished: total sugars, reducing sugars (glucose and fructose), and fructose/glucose ratio. To accomplish the analyses, the seeds were taken out and the berries were ground, with their skin and pulp. The quality of the fruits harvested during periods that do not include the peak production, that is, fruits originated from anticipated pruning, was in accordance with the quality standards demanded by the legislation. It was also observed that irrigation hinders the sugar production in the grape, reducing its content.