Effect of Pre-Harvest Treatments of Peach Trees on Fruits Quality Characters during Cold Storage

Abstract

This research was carried out during two successive seasons of 2016 and 2017 to study the effect of pre-harvest treatments on peach trees on fruits quality at harvest time and during cold storage at 5±1°C and 80-85% RH. The selected trees for this study were chosen from locally Mit-Ghamer peach trees(cv. Medium Sultani), grown in a private orchard at Fesha-Bana village, Aga Center, Dakahllia governorate, Egypt. The selected trees of peach (cv. Medium Sultani) were sprayed Pre-harvest (1.5 month after full bloom) with one of the followings: tap water (control), 1.5% potassium sulphate (K2SO4), 2% calcium chloride (CaCl2) and the combination of them. The harvested mature fruits were cold stored at 5 ± 1°C and 80-85% relative humidity (RH) for a storage period of 24 days. Some physical and chemical quality characteristics were measured on the intact treated fruits at harvest date and at 6-day-intervals during cold storage up to 24 days. The obtained results showed that the peach fruits sprayed with 1.5% K2SO4 recorded the highest values of firmness, Vitamin C content and TSS% after 6, 12 and 18 days during The cold storage in both seasons. While, peach trees sprayed with 2% CaCl2 gave the highest values of fruit firmness at harvest time and after 24 days of cold storage, and the lowest value of fruits decay incidence%, TSS% and anthocyanin content in fruit skin in all storage periods of both seasons. Applying the combination treatment of 1.5 % K2SO4 and 2% CaCl2 showed the highest values of vitamin C, acidity and total sugars%, anthocyanin and pectic substances contents as well as the lowest value of TSS/acid ratio and weight loss% of fruit at 18 and 24 days of cold storage in both seasons. However, the opposite trends were true for the control treatment. Finally, it can be recommended applying the combination spray of 1.5 % K2SO4 and 2 % CaCl2 on peach trees at pre-harvest (1.5 month after full bloom) to improve maintaining physical and chemical qualities of peach fruits during cold storage up to 24 days.