Fitorreguladores em pré-colheita e armazenamento de maçã ‘galaxy’ em atmosfera controlada com e sem aplicação de 1-metilciclopropeno

Abstract

Reduction of pre and postharvest losses in apples is necessary for the producers and storers to have a higher economic return. In this context, we aimed to evaluate the effect of pre-harvest spraying of different combinations of growth regulators on pre and postharvest losses. This dissertation is composed of two research works (articles). In the first one, the effect of the isolated or combined spraying of aminoethoxyvinylglycine (AVG), naphthalene acetic acid (NAA) and 2-chloroethyl phosphonic acid (Ethephon) on the pre-harvest fruit drop and the quality of 'Galaxy' apple after the harvest was evaluated. In the second, five treatments were selected which resulted in better quality of the fruits after harvesting and after stored in controlled atmosphere (CA) and CA plus 1-methylcyclopropene (1-MCP) treatment, to evaluate the effect of growth regulators on post storage fruit quality. In the first work, the spraying of AVG+NAA (sprayed 35 and 15 days before harvest - DBH, respectively) reduced fruit drop as compared to other treatments, in addition, it maintained higher fruit quality during the shelf life, by reducing the ACC oxidase enzyme activity, internal ethylene concentration (IEC), ethylene production, respiration rate, electrolyte leakage and maintained high flesh firmness. AVG applied alone or combined with other growth regulators did not delay the development of the red skin color. AVG spray alone reduced less the fruit drop as compared to AVG+NAA (sprayed 35 and 15 DBH, respectively), but maintained similar fruit quality. The isolated or combined spraying of NAA with Ethephon decreases fruit quality during shelf life, by high IEC, ethylene production, respiration rate and reduced fruit flesh firmness. In the second work, fruit stored in CA (1.2 kPa O2 + 2.0 kPa CO2), sprayed in pre-harvest with AVG alone or combined with NAA or NAA+Ethephon, resulted in low ethylene production, mealiness incidence, higher flesh firmness and healthy fruit amount as compared to the control (without growth regulator) and AVG+Ethephon. When fruit were storage in CA with 1-MCP application, fruit from plants sprayed with AVG and AVG+NAA had reduced ethylene production, respiration rate, electrolyte leakage, mealiness incidence, decay and maintained higher flesh firmness and healthy fruit, compared to control (only 1-MCP application) and AVG+Ethephon. Combined AVG+NAA+Ethephon spraying in pre-harvest and postharvest 1- MCP application resulted in fruit with low decay incidence, high percentage of healthy fruit, but with lower flesh firmness and higher mealiness incidence as compared to AVG and AVG+NAA. Taking into account the fruit drop and the physical-chemical analyzes at harvest and post-storage, the spraying of AVG+NAA (sprayed 35 and 15 DBH, respectively) was the treatment which more reduced losses in pre and postharvest in ‘Galaxy’ apple.