فهرست مطالب masoumeh kiaeshkevarian

Pre-harvest citrus fruit splitting is a physiological disorder that causes significant damage to producers of susceptible cultivars by reducing the amount of crop available on the market. Proper management of tree nutrition and paying special attention to the three key elements of potassium, calcium, and boron, which are involved in the strength of cell walls and fruit peel flexibility, can be effective in reducing the fruit splitting severity. Therefore, an experiment has been carried out in the Ramsar (Citrus and Subtropical Fruits Research Center) during 2018 and 2019 to investigate the effects of foliar application of 1.0% potassium nitrate, 1.0% calcium nitrate, and 0.5% boric acid at the end of June drop on reducing the severity of splitting and some fruit traits of Page mandarin. This study is 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 show that the treatments especially 1.0% potassium nitrate have reduced pre-harvest fruit splitting, increased the yield, and improved the quantitative and qualitative fruit traits. However, they have had no significant effect on the activity of polygalacturonase enzyme, cell density of blossom-end, and navel diameter. Overall, foliar application of nutrients, especially 1.0% potassium nitrate, could be suggested as an effective approach to control pre-harvest fruit splitting and boost the quantity and quality of page mandarin fruit.

In order to evaluate the effect of different preharvest fertilization methods on quantitative and qualitative characteristics of kiwifruit (var. Hayward) at postharvest stage, an experiment was conducted in a randomized complete block design with 8 treatments in four replications in Citrus and Sub-tropical Fruits Research Center during three crop years (2014- 2016). Fertilizer treatments included broadcast application (control), localized placement, strip, foliar, fertigation, broadcast application + foliar, fertigation + foliar and localized placement + foliar. Then in the first of November in each year, sampling of the treated fruits was carried out to measure the quantitative and qualitative characteristics of the fruit at postharvest stage during three years. Harvested fruits were kept cold storage at 0.5 ° C and 90% relative humidity for three months. The results showed, the fertilizer method had a significant effect on the fruits weight loss. So that the fruits fed by strip (6.08%), fertigation (6.74%) and combination of fertigation and foliar application (6.61 %) methods had less weight loss during cold storage, respectively. L * and chroma content of flesh were affected by the fertigation method. Result also showed that the control fruits had the lowest amount of antioxidant capacity and strip fertilization treatment had the highest antioxidant capacity during cold storage. Sensory attributes analysis showed that the amount of aroma, flavour, off-flavour, sweetness, sourness and overall fruit acceptability in fruits treated by broadcast application + foliar method obtained the most desirable scores.