Effect of Different Concentrations of Spermidine at Different Harvesting Times on the Quality of Apricot Fruits ”Shahroudi“ Cultivar

Apricot is one of the most important horticultural crops because of its attractive taste and nutritive value. Different cultivars of apricot contain highly variable content of ascorbic acid, cartenoids, and phenolic compound,which are good sourecs of antioxidant. Fuit quality is an important trait for concumers and producers. The purpose of this work was to estimate the effects of pre-harvest application of polyamines on quality characteristics of apricot fruits at the end of fruit ripening process.

The experiment was carried out as a factorial based on the randomized complete block design (three concentrations of spermidine at three harvesting time) with four replications. The selected branches of trees were sprayed as a pre-harvesting application method by three concentrations of spermidine (0, 2, and 3 mili molar) 7 days before commercial harvesting time. Fruits were harvested during harvesting times (3 days interval) and then some fruit characteristics such as total soluble solids (TSS), total ccidity (TA), vitamin C, firmness of fruit tissue, pH of fruit extract, total phenol, flavonoid, and total antioxidant capacity were measured in the laboratory of flower biology and fruit growth development at the department of horticulture, faculty of agiculture, university of Tabriz.

The results showed that the effects of different harvesting times were significant regarding all traits. The best results were observed in 3 mM spermidine and this treatment improved all the measured characteristics of fruit. The highest value of total antioxidant capacity (3.01%), vitamin C (3.29%), and fruit firmness (3.27%) were found in 3 mM spermidin at three harvesting times. In some characteristics such as TSS and TA, there was no significant difference between 2 and 3 mM spermidine, but among treated and non-treated fruit a full significant difference was observed. We assume that the second harvesting time can be the best harvesting time regarding fruit quality parameters. During fruit ripening, the amount of TSS and TA increased, while firmness, total phenolic, and flavonoids compounds and total antioxidant capacity decreased gradually.

Fruit physicochemical properties are very important for understanding the product behaviour during the harvesting, transporting, packaging, and storing of fruit crops. The results of this study showed that the pre-harvesting application of polyamines delayed the ripening and increased the quality of fruit during the different harvestings times.