Physiological and molecular mechanisms underlying graft compatibility.

Abstract

Grafting has been used for millennia to increase uniformity, vigour and resistance to biotic and abiotic stresses (e.g. low soil temperature, drought, salinity and flooding) of vegetatively propagated plants (Hartmann et al., 2002; Lee and Oda, 2003; Mudge et al., 2009). The grafting technique plays an important role in the production of horticultural crops, including fruit trees, ornamental plants and vegetable crops (Lee and Oda, 2003); it can be considered an important and alternative innovative practice of integrated pest management and a promising alternative for soil fumigants in vegetable production (Guan et al., 2012). Currently, although the use of grafted plants is increasing rapidly, the practice of grafting remains limited, mainly due to inconsistent grafting success (Hartmann et al., 2002). Considering the variation of graft compatibility between even closely related species, it is necessary to evaluate graft compatibility before considering the use of a rootstock with a specific scion genotype (Lee et al., 2010; Guan et al., 2012). Although a number of rootstocks are available, little information is provided related to scion–rootstock compatibility. This issue should be considered, as the performance of a grafted plant depends on the properties of the scion and rootstock genotypes, the compatibility of the rootstock with the scion, environmental conditions and cultivation methods (Andrews and Serrano-Marquez, 1993; Lee, 1994). Given the relative importance of graft compatibility throughout the world,there has been surprisingly little research dedicated to the study of this phenomenon. The large number of genotypes that can be combined by grafting produces a wide range of different physiological, biochemical and anatomical interactions to study, slowing down the progress in this research area. The aim of this chapter is to review the biology of grafting and the factors influencing graft compatibility, focusing on the molecular and physiological aspects affecting graft development and success in herbaceous and woody plants.