ABSTRACT
Genetic linkage maps are useful for a variety of applications, especially in taxa lacking complete genome sequences. Common applications include understanding genome organization and evolution, performing comparative genomic studies, as well QTL analysis. The majority of linkage maps in forest trees have been developed for genera of economic importance, viz. Pinus, Picea, Populus, Quercus, Castanea and Eucalyptus (Neale and Kremer 2011), of which Eucalyptus is among the best studied. Linkage mapping projects in eucalypts were initiated soon after the advent of DNA-based markers in the 1980s, with the fi rst complete map published in 1994 (Grattapaglia and Sederoff 1994). Since then, major advancements have been achieved; largely refl ecting the evolution in available molecular markers, as well as mapping algorithms and software, and in some cases the use of larger and better designed mapping pedigrees. Currently, individual tree and consensus linkage maps have been reported for some 14 pedigrees, generally including fewer than 400 dominant and/or codominant markers and achieving greater than 90% map coverage (Grattapaglia et al. 2012). Linkage maps have been constructed for the eucalypt species of greatest commercial importance, all of which belong to the subgenus Symphyomyrtus; mostly in E. grandis, E. urophylla and E. globulus (Table 5-1), while fewer linkage maps have been constructed for other commercial species, E. nitens (Byrne et al. 1995; Thamarus et al. 2002; Thumma et al. 2010), E. tereticornis (Marques et al. 1998; Gan et al. 2003), E. camaldulensis (Agrama et al. 2002) and species from the closely related genus Corymbia (Shepherd et al. 2006).
