Current status of vegetable grafting: Diffusion, grafting techniques, automation

Vegetable production with grafted seedlings was originated in Japan and Korea to avoid the serious crop loss caused by infection of soil-borne diseases aggravated by successive cropping. This practice is now rapidly spreading and expanding over the world. Vegetable grafting has been safely adapted for the production of organic as well as environmentally friendly produce and minimizes uptake of undesirable agrochemical residues. The number and size of commercial vegetable seedling producers has increased markedly reflecting the increase in farmers' preferences for grafted seedlings of high-quality and better performance. In addition to the widely recognized advantages of disease tolerance and high crop yields, grafting technology is also highly effective in ameliorating crop losses caused by adverse environmental conditions such as low soil temperature and high soil salts, especially under protected cultivations where successive cropping or continuous farming is routinely practiced. Grafted seedlings are much favored in hydroponics farming systems where the chances of rapid spread of noxious diseases, once infected, is high. Active research has been focused to develop efficient rootstocks and handy grafting tools. In addition, researchers are eager to develop grafting machines or robots to reduce the higher price of grafted seedlings. The quality of grafted transplants is extremely important to maximize high-quality crop yield. Use of grafted vegetables has increased with the increased use of improved soil mix or substrate, farmer's preferences for better seedlings, efficient management of nursery systems, lower prices of grafted seedlings, and efficient nationwide delivery and/or transportation system. Improved grafting methods to cut down the labor cost for grafting and subsequent handling of plug-grown grafted transplants will contribute further to the increased use of grafted vegetables worldwide. (C) 2010 Elsevier B.V. All rights reserved.