Effect of foliar application of some nutrient elements on traits related to fruit splitting of Page mandarin

Preharvest fruit splitting disorder causes significant damage to producers of sensitive citrus cultivars, therefore, proper management of tree nutrition with key elements reduces the probability the occurrence of this disorder can be effective in reducing fruit splitting. Accordingly, to investigate the effects of foliar application of 1% potassium nitrate, 1% calcium nitrate and 0.5% boric acid in combination with each other at the end of June drop on reducing the intensity of fruit splitting and some traits of Page mandarin fruit two years experimental was done in 2018 and 2019. This study was performed according to a combined analysis in time with two factors including years of experimentation and different treatments of foliar application of nutrients, based on randomized complete block design with three replications. The results showed that foliar application caused a change in the amount of calcium, potassium and boron in the leaves and fruits of Page mandarin. Moreover, it was found that these treatments, especially the combined treatment of three elements, reduced the intensity of preharvest fruit splitting and increased the yield and improved the quantitative and qualitative traits of the fruit, whereas had no significant effect on the activity of polygalacturonase enzyme, cell density of blossom-end and navel diameter. Overall, foliar application of nutrients including the combined treatment of potassium nitrate, calcium nitrate and boric acid, can be introduced as an effective approach to control preharvest fruit splitting and increase the quantity and quality of Page mandarin fruit.