Postharvest quality of ‘brookfield’ apple field-treated with naphthalene acetic acid alone or combined with other growth regulators

Abstract

The Gala cultivars represent about 65% of the Brazilian apple production, however, it has a short harvest period, making necessary to use technologies that anticipate or delay fruit maturation. A widely used technology is the preharvest application of growth regulators. The objective of this investigation was to evaluate the effect of preharvest application of naphthalene acetic acid (NAA) combined with aminoethoxyvinylglycine (AVG) and 2-chloroethylphosphonic acid (Ethephon), on the quality of ‘Brookfield’ apple at harvest and after eight months controlledatmosphere (CA) (1.2 kPa O2 and 2.0 kPa CO2) storage followed by seven days of shelf life at 20 °C. The treatments were: [1] Control: application of water only; [2] NAA (40 g.ha-1); [3] NAA (40 g∙ha-1) plus Ethephon (2.0 L∙ha-1 24% of active ingredient), and [4] NAA (40 g∙ha-1) plus AVG (0.83 kg.ha-1 15% of active ingredient). At harvest, fruit treated with NAA presented a higher level of starch degradation, ethylene production and respiration rate. Fruit treated with NAA plus AVG maintained better quality after eight months under CA storage plus seven days of shelf life, due to higher healthy fruit amount and higher flesh firmness, but this combination reduced the red skin color index. Additionally, NAA plus Ethephon may be an alternative to maintain the quality of ‘Brookfield’ apple during storage in comparison to the application of NAA isolated.