Impact of grafting on product quality of fruit vegetables

In horticultural industry, the focus has traditionally been on yield. However, in recent years consumers interest in the quality of vegetable products has increased worldwide. Vegetable quality is a broad term and includes physical properties (1), flavor (2), and health-related compounds (3). Grafting vegetable plants onto resistant rootstocks is an effective tool that may enable the susceptible scion to control soilborne diseases, environmental stresses and increase yield. However, in these cases, the characteristics of the three areas might be affected by grafting as a result of the translocation of metabolites associated with fruit quality to the scion through the xylem and/or modification of the physiological processes of the scion. Possible quality characteristics showing these effects could be fruit appearance (size, shape, color, and absence of defects and decay), firmness, texture, flavor (sugar, acids, and aroma volatiles) and health-related compounds (desired compounds such as minerals, vitamins, and carotenoids as well as undesired compounds such as heavy metals, pesticides and nitrates). There are many conflicting reports on changes in fruit quality due to grafting and whether grafting effects are advantageous or deleterious. The differences in reported results may be attributable in part to different production methods and environments, type of rootstock/scion combinations used, and harvest date. This report gives an overview of the recent literature on the effects of grafting on fruit vegetable (Solanaceae and Cucurbitaceae) quality including physical properties, flavor and health-related compounds of the product. The review will conclude by identifying several prospects for future researches aiming to improve the product quality of grafted vegetables. (C) 2010 Elsevier B.V. All rights reserved.