In-vitro grafting – Current applications and future prospects

•In-vitro grafting is an alternative to conventional grafting for asexual plant propagation.•In-vitro grafting is useful for studying scion-rootstock interactions, long-distance signalling and virus indexing/elimination.•In-vitro grafting is an efficient tool for validating graft incompatibility due to juvenility of scion and rootstock used.•Acclimatisation stage is required for in-vitro grafts to get prepared for transition to field (in vivo) environment. In-vitro grafting involves grafting a micro-scion onto a micro-rootstock under aseptic conditions. Due to juvenility and health status of the source plants for microscion / microrootstock, in-vitro grafting possesses many advantages over traditional field / bench grafting methods. So far, in-vitro grafting has been used for producing virus-free plants as well as studying scion-rootstock interactions, long-distance signalling and virus-indexing. However, this technique has other potential applications, such as propagation of fruit trees and crop improvement, which has been neglected. This article reviews recent applied methodologies and their findings in the last 20 years, and discusses challenges and future direction of in-vitro grafting.