Hybrids and mini-cutting: a powerful combination that has revolutionized the Eucalyptus clonal forestry

Background Eucalypt canker disease (Chrysoporthe cubensis) was the main driver of the concept of eucalypt clonal forestry in Brazil. Initially clonal forestry was based on outstanding spontaneous hybrids resistant to canker disease. Since the recognition that cloning superior inter-specific hybrids could be an important general strategy, several crosses were made for many different purposes, especially pulp & paper, charcoal and more recently veneer and solid wood. This strategy has been responsible for a significant advance in the forest productivity of Eucalyptus. The underlying foundation for this strategy has been the exploitation of heterosis observed in most inter-specific crosses. Due to its importance, hybridization and cloning currently constitute a key component of almost all forest-based industrial plantations in Brazil. Significant progress has taken place in the last few years with the different techniques used to carry out controlled crosses and cloning.