ABSTRACT The objective of this work was to evaluate the effect of extremely low-oxygen storage on the aerobic, anaerobic metabolism and overall quality maintenance of ‘Royal Gala’ and ‘Galaxy’ apples stored at two temperatures. For ‘Royal Gala’ apples, four treatments were evaluated in a two-factor scheme (2 × 2), with two storage conditions: [1] 1.2 kPa O2 + 2 kPa CO2; [2] 0.8 kPa O2 + 1.6 kPa CO2; and two temperatures (1.0 and 1.5 °C). For ‘Galaxy’ apples, the experiment was conducted in a two-factor (3 × 2) scheme with three storage conditions: [1] 1.2 kPa O2 + 2 kPa CO2; [2] 0.8 kPa O2 + 1.6 kPa CO2; [3] 0.4 kPa O2 + 1.2 kPa CO2, and two temperatures (1.0 and 1.5 °C). The ‘Royal Gala’ apples stored under 0.8 kPa O2 + 1.6 kPa CO2 at 1.5 °C had higher flesh firmness, healthy fruit and soluble solids along with lower incidence of flesh breakdown and mealiness. The ‘Galaxy’ apples stored under 0.4 kPa O2 + 1.2 kPa CO2, at temperature of 1.5 °C had lower 1-carboxylic acid-1-aminocyclopropane (ACC) oxidase enzyme activity, ethylene production, occurrence of mealiness, when compared to 1.0 °C. The storage of these two cultivars at 1.5 °C with extremely low O2 partial pressures is possible. The possibility to increase the storage temperature from 1 °C, which is traditionally used for these mutants, to 1.5 °C allows to keep better quality with the advantage of energy saving.

ABSTRACT The aim of this study was to evaluate the effect of storing ‘Royal Gala’ apple under extremely low oxygen partial pressures on their anaerobic metabolism, ethylene production and fruit quality after 9 months of storage plus 7 days of shelf life at 20 °C. The storage conditions tested were: 1.2 kPa O2 + 2.0 kPa CO2; 0.7 kPa O2 + 1.5 kPa CO2; 0.5 kPa O2 + 1.2 kPa CO2; 0.4 kPa O2 +1.2 kPa CO2 and 0.25 kPa O2 + 0.0 kPa CO2. The fruit storage temperature was 1.0 °C (± 0.1). Fruit stored at 0.4 kPa O2 + 1.2 kPa CO2 maintained higher flesh firmness and a higher percentage of healthy fruit. The fruit stored under the 0.25 kPa O2 + 0.0 kPa CO2 condition had lower flesh firmness as well as a reduced percentage of healthy fruit and a high production of anaerobic metabolism compounds, such as ethanol and ethyl acetate, which may have caused fruit quality loss. The storage of ‘Royal Gala’ apple under 0.4 kPa O2 + 1.2 kPa CO2 is a technique that can be commercially applied to keep a better fruit quality after a 9 months storage period.

RESUMO A podridão parda do pessegueiro, causada pelo fungo Monilinia fructicola, é a principal doença da cultura, causando danos significativos tanto em pré-colheita como pós-colheita. O estudo objetivou avaliar a aplicação pré-colheita de fungicidas, no controle da podridão parda e verificar o papel da infecção latente e contaminação externa na incidência da doença em pós-colheita. Foi conduzido um experimento nos anos de 2014 e 2015 para avaliar o desempenho de seis ingredientes ativos em pré-colheita (captana, iprodiona, iminoctadina, tebuconazol, difenoconazol e azoxistrobina) no controle da podridão parda e o efeito sobre infecções latentes. Um segundo experimento objetivou monitorar a infecção latente durante o crescimento e maturação dos frutos, correlacionando-a com a incidência da doença em pós-colheita. Os dados formam submetidos a análise de variância (Anova) e as médias agrupadas pelo teste de Scott-Knott (p < 0,05) com o software estatístico Sisvar. Os produtos iprodione, tebuconazol e difenoconazol foram os mais eficientes no controle da podridão parda a campo, enquanto o iminoctadine possui maior eficiência em pós-colheita, agindo inclusive sobre as infecções latentes. A incidência de infecções latentes tanto na fase de crescimento quanto maturação tem correlação positiva com a podridão parda em pós-colheita. A maior incidência da doença após o armazenamento foi em decorrência da manifestação de infecções latentes. O eficiente controle químico no campo, durante toda a fase de crescimento e maturação dos frutos é uma importante estratégia para o controle pós-colheita, inclusive após o armazenamento refrigerado e durante a vida de prateleira sob 20 oC.

ABSTRACT The peach brown rot, caused by Monilinia fructicola, is the main disease of the crop, causing significant losses during preharvest and postharvest. This study aimed to evaluate the performance of preharvest fungicide application on brown rot control and verify the role of latent infection and external contamination in postharvest disease. An experiment was carried out in the years 2014 and 2015 in order to evaluate the performance of six active ingredients (captan, iprodione, iminoctadine, tebuconazole, difenoconazole and azoxystrobin) during preharvest on brown rot control and the effect on latent infection. A second experiment was carried out to monitor the latent infection during growth and ripening of the fruit and in order to correlate it with the postharvest disease incidence. The data were submitted to analysis of variance (Anova) and the means were grouped by the Scott-Knott test (p < 0.05), using statistical software Sisvar. The active ingredients iprodione, tebuconazole and difenoconazole were the most efficient in controlling brown rot on the field, while iminoctadine has higher efficiency during postharvest control, acting on latent infections. The incidence of latent infections during fruit growth and ripening has a positive correlation with brown rot incidence at postharvest. The highest disease incidence after storage is due to the latent infections manifestation. Effective chemical control in the field, throughout the growing and ripening of fruit, is an important approach to postharvest brown rot control, even after cold storage and during shelf life at 20 °C.