foliar application of potassium and bron during pomegranate (punica granatum) fruit development can improve fruit quality

Abstract

Abstract. The aim of this work to evaluate the effects of different dose of potassium and boron foliar application on fruit quality parameters of pomegranate fruit (Punica granatum .L). To achieve this objective, in 2007 a trial was carried out in a pomegranate orchard located in Ferdows region (Iran). The plants were sprayed with three potassium (0, 1.5, 3 g/lit potassium metalosate) and three boron (0, 1500, 3000mg/lit boric acid) doses, in a complete randomized design with three replication and spraying replicated three times during fruit development stage. Foliar application of potassium and boron significantly increased the content of potassium and boron in the leaf (p≤0.01) and the peel and juice of fruit (p≤0.05). The fruit fertilized at the highest potassium dose had higher titrable acidity and total soluble solid than other treatments. Foliar application of potassium (1.5 and 3g/lit doses) significantly (p≤0.05) increased the content of anthocyanin, phenolic compound and antioxidant activity of fruit juice. Application of potassium high dose (3g/lit) alone decreased the fruit firmness significantly while the spraying of boron high dose (3000mg/lit) increased the fruit firmness significantly. Content of ascorbic acid increased significantly with increasing of potassium doses and the highest content of ascorbic acid observed in combination of potassium high dose (3g/lit) and boron application. Foliar application of boron significantly (p≤0.05) increased the peel content of fruit, while it decreased significantly (p≤0.05) the juice content of fruit. Treatment of potassium high dose (3g/lit) alone and with combination of boron treatments showed the highest significant content of total sugar. Electrolyte leakage of fruit peel decreased significantly (p≤0.05) by foliar application of potassium doses compared with no potassium fertilizer application.