The effect of seaweed foliar application on yield and quality of apple cv. 'Golden Delicious'

Apple is one of the most important horticultural products, and the present study aimed to evaluate the effects of foliar application of seaweed extract on the yield, physiological traits, and concentrations of some elements in apple cv. 'Golden Delicious'. The experiment was performed as a randomized complete block design with 5 replications in an orchard of Semirom. Treatments were included 2 extracts of seaweed Seafer-100 (800 and 1,200 mL/1000 L) and Macys BC28 (2,000 and 2,500 mL/1000 L) as well as control (spraying distilled water). In this study, we measured traits including yield characteristics (yield/tree and hectare, fruit weight, firmness, and diameter), physiological traits (titratable acidity, soluble solids content, ascorbic acid, proline, phenol, soluble sugars concentration, chlorophyll a, b, total chlorophyll, carotenoids, peroxidases, ascorbate peroxidases, cata-lases, proteins, and relative leaf-water content), and elements (N, P, K, Zn, Fe, Mg, and Cu). The general results showed that the application of seaweed extract lead to a significant increase in most of the studied traits compared to the non-application of this treatment. This means that by increasing the concentration of both seaweed extracts, yield characteristics, most of the physiological traits, and some elements increased signifi-cantly. After the use of seaweed extract, the concentration of N, Fe, and P, chlorophyll a and b, relative water content, fruit size, and yield increased. In general, the use of seaweed extract improved the fruit quantity and quality of this important product. Therefore, it is recommended to use seaweed extract in 'Golden Delicious' apple orchards.