Pre-harvest Treatments to Reduce Incidence of the Soft Scald and to Enhance Coloration of “Anna” Apple Fruits

Abstract

Few attempts have been made to overcome problem of the soft scald. Many factors and conditions are associated with such physiological disorder. In this study, seven-years-old Anna apple trees were preharvest sprayed during 2016 and 2017 growing seasons with lisophos 1000mg/ litre, potassium sulphate 2%, calcium sulphate 2% and their combinations in order to investigate their influence on initiation of the soft scald and fruit quality especially fruit coloration at harvest as well as keeping fruit quality during storage for seven days on refrigerator. Lisophos alone or plus either calcium sulphate or potassium sulphate reduced initiation of the soft scald at harvest as compared with untreated fruits, in addition to retarding the loss of fruitfirmness. The application of potassium sulphate alone or incorporated with lisophos treatment increased fruit diameter, fruit TSS, total sugars, peel anthocyanin and carotene contents but decreased fruit acidity, peel chlorophyll a and b as compared with control. After seven days of refrigerated shelf life, the application of lisophos plus calcium sulphate retarding the loss of flesh firmness, reduced weight loss% and incidence of the soft scald percentage. This study provided evidences about the possibility of reducing incidence of the soft scald in Anna apples by preharvest application of lisophos plus either calcium sulphate or potassium sulphate, while, enhancing fruit quality and coloration.