The interaction of potassium and iron on nutritional quality of apple fruit during storage life

Adiquate fertilization of fruit trees after harvest will increase fruit yield and quality in coming year. To investigate the effects of potassium sulphate (0, 50, 100 and 150 g) and iron chelate (0, 10, 20 and 30 ml) on fruit quality after harvest, a factorial experiment in randomized complete block design study was performed on apple ̔ Red Delicious ̓ with 3 replications and traits such as firmness, total soluble solids, titrable acidity, anthocyanin and phenole in flesh and skin, total carbohydrate, dry matter percentage, prelim index and concentration of some macro and micro elements of fruit were measured. The Results showed that trees fertilized with 50g of potassium sulphate and 30 ml iron chelate had firmer fruits and more soluble solids. Also the effect of potassium on increasing anthocyanin in fruit skin was more than iron. Despite the decreasing trend in phenol content during storage, potassium Sulphate fertilizer had the greatest effect on increasing the amont of phenol in skin and flesh and even maintaining it during storage compared to the control. On the other hand, with increasing in the amont of iron chelate, the amont of phenols in fruirs decreased. The acidity of fuits in treatments treated with different concentrations of iron was higher than control fruits. Inceasing storage time caused a significant increase in total carbohydrate. Other quality traits decreased were decreased significantly during storage. In Genral, treatment of with 50 and 100 g of potassium sulphate alone or in combination with 10 ml of irone chelate had a good effect on the studied tratis.