Effect of foliar application of iron and zinc on some quantitative and qualitative attributes of apple fruit ‘Delbar estival’

This study was carried out on the effect of iron and zinc foliar applications on quantity and quality trait of apple ‘Delbar estival’ fruit. The research experiment was carried out as factorial in a randomized complete block design with 3 replications on 8-year-old ‘Delbar estival’ apple trees on M9, trained to Y system in Horticultural Department, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran. During growth season, iron chelate (Fe-EDDHA) in three levels (0, 50, 100 mg/l) and zinc sulfate in three levels (0, 5, 10 mg/l) were sprayed 30, 60 and 90 days after full-bloom. Harvested fruits were transferred to cold storage with 0±1˚C and 85-90% relative humidity and kept for 5 months. In order to measure the treatments effects on qualitative and quantitative fruit traits, samples were assessed at harvest time and monthly intervals during cold storage. Results showed that increased Fe concentration caused enhancement of fruit flesh firmness, vitamin C, soluble solids, antioxidant content and dry matter. Zn could increase vitamin C, soluble solids, dry matter but reduced flesh firmness and total phenols. It can be concluded that, iron and zinc application was suitable for improving the quality indexes for this apple cultivar.