IMPROVING THE QUALITY OF FRESH-CUT WATERMELON THROUGH GRAFTING AND ROOTSTOCK SELECTION

Abstract

The shelf life and over-all quality of fresh-cut watermelon from two cultivars grafted onto four rootstocks were compared with fresh-cut fruit from the nongrafted cultivars. Fresh-cut cubic pieces of about 4.5 cm per side were prepared from ripe watermelons grown at the Lane Research Station and were stored at 5 °C in 35-oz PETE containers. Quality attributes of firmness, soluble solids content, lycopene content, and bacterial counts of the pieces were measured after 0, 5, and 10 days of storage. Sugar content of the cut fruit was independent of rootstock and remained constant over the ten days of storage. Lycopene content of the fruit decreased by 5% to 10% during the storage period, regardless of treatment. Bacterial count on the fruit from all treatments remained low and variable during the ten days at 5 °C. Firmness of cut pieces from fruit originating from the grafted plants was dependent upon the rootstock employed, and melons from grafted plants possessed firmer fruit than did those from the nongrafted plants. Overall, the firmness of fruit from all sources decreased 20% to 30% during the ten days of cold storage. However, the firmness of fruit from some of the rootstocks after 10 days of storage was equal to or significantly higher than that of the fruit from nongrafted plants when it was initially cut. Thus, these studies suggest that grafting to a proper rootstock will produce fresh-cut watermelon that is equal in sweetness and lycopene content to its nongrafted counterpart, but it will possess greater crispness throughout its storage on the supermarket shelf.