Implications of phenolic compounds in graft incompatibility in fruit tree species

Cultivar stability in fruit tree species is ensured by grafting on particular rootstocks and a fruit tree can be considered as a symbiosis between scion and rootstock. However, heterospecific grafts are often incompatible resulting in death of the tree. The causes of graft incompatibility remain still unknown, although many biochemical events are affected. Phenol compounds play an important role in plants and constitute an important group in scion-rootstock relations. In this review, their implications in the mechanism of the incompatibility in the early steps of graft establishment have been reviewed with the aim of providing a framework for an early detection of incompatible grafts to increase the efficiency in rootstock breeding. (C) 1998 Elsevier Science B.V.