Effects of ethephon, aminoethoxyvinylglycine (AVG) and reflective mulch treatments on the fruit coloring and postharvest quality of 'starking delicious' apple cultivar grown in Elmalı region

In this study, 'Starking Delicious' apple cultivar was treated with ethephon, aminoethoxyvinylglycine (AVG), reflective mulch and its combinations for the enhancement in skin color. For that purpose, the study was conducted in 2013-2014 and the effects of preharvest treatments on skin color (C*, h°), titratable acidity (TA), fruit firmness, total soluble solids (TSS) in 'Starking Delicious' apple cultivar were determined. Reflective mulch, ethephon and reflective mulch+ ethephon combination enhanced the occurrence of red color in 'Starking Delicious' apples. Additionally, no significant effects of tested materials for coloring,fruit firmness, TSS and TA were observed. In the second part of the study, the effect of once and repeated application of 625 ppb dose of 1-methylcyclopropene (1-MCP) on the fruit quality and storage performance of 'Starking Delicious' apples under normal atmosphere conditions were investigated. 1-MCP treated fruits were stored for 180 days at 0°C temperature and 90±5% relative humidity. 1-MCP application was repeated after 90 days of harvesting. Fruits samples from different storage conditions were taken at 45 days of interval whereas the fruits were kept at 20°C and various physicochemical analysis were recorded at span of 7 days during shelf-life conditions. Fruit firmness decreased while weight losses of fruits increased in all treatments. Apples with repeated application of 1-MCP were firmer throughout and at the end of storage as compared to other treatments. During storage, TA declined in all the treatments. 1-MCP and repeated application of 1-MCP in apples effectively maintained the TA. During both years the amount of TSS continuously increased in storage. No significant differences existed between 1-MCP and repeated application of 1-MCP in term of fruit skin color (C*, h°), while treatments had significant effects on h° value when compared to control. Typical respiratory climacteric was displayed by apple fruits in the measurement of respiration and ethylene production. Additionally, the respiration rates and ethylene productions of apples were increased with extending storage duration. On the other hand, 1-MCP and repeated 1-MCP application in apple fruit exhibited less respiration rates and ethylene productions as compared to control treatment. Total anthocyanin content in apple fruit first increased then decreased during storage. It can be concluded that reflective mulch, ethephon, reflective mulch and their combination had successfully increased the coloring of apple fruit among the treatments applied in field conditions. In cold storage, repeated application of 1-MCP on 'Starking Delicious' apples had positive impacts on the storage duration, fruit quality and shelf life performance. 'Starking Delicious' apple cultivar can be stored under normal atmospher condition at 0°C temperature and 90±5% relative humidity for 6 months with less postharvest losses in storage.