The effects of pre-harvest foliar spray and post-harvest dip of ethephon on the physiology and quality of orange fleshed sweet potato apomuden during storage

Abstract

The postharvest storage of sweet potato roots in the tropics is a major challenge in the crop’s value chain as it deteriorates readily in the hot climate. Although prolonged storage in the cold chain has been shown to be feasible, technical and economic constraints in the tropics makes cold storage inaccessible to growers and retailers of sweet potato. It has been demonstrated in several studies that the plant hormone ethylene greatly influences metabolic changes in many types of horticultural produce postharvest and that controlled application can improve storage. In this research, the ethylene analogue ethephon was applied at four different concentrations as foliar spray on the Orange-Fleshed Sweet Potato Apomuden seven days before harvest and stored in the ambient. Untreated roots were also dipped in the same ethephon concentrations postharvest. Changes in the physiological and biochemical quality (preharvest treatment only) viz. weight loss, sprouting, decay, shrinkage, dry matter content, starch, sucrose, glucose, fructose and minerals concentration were studied. Preharvest foliar application of ethephon resulted in superior storage performance than postharvest root dip as it better reduced sprouting, improved resistance to weevil damage and shrinkage. Preharvest application of 500 ppm ethephon significantly reduced the dry matter loss compared to the control. Furthermore, carbohydrates, proteins and minerals were significantly more abundant in the ethephon treated roots.