ABSTRACT
Desirable traits for genetic mapping in Eucalyptus include those which are diffi cult and expensive to measure by conventional means (e.g., wood quality), traits expressed in later stages of development (e.g., fl owering times) and traits expressed under specifi c environmental conditions (e.g., pest resistance, drought and frost tolerance, etc.). Often traits of interests tend to be correlated and extensive phenotypic datasets may be summarized in a few principal components (Dillon et al. 2010; Dillon et al. 2012; Sexton et al. 2012). Several approaches to QTL mapping have been used to dissect relationship between genetic (QTL) map position, with the fi rst QTLs in Eucalyptus being developed in the mid-90s by Grattapaglia et al. (1995) and Vaillancourt et al. (1995). The identifi cation of several major effect QTLs provided an optimistic outlook that one or a few closely linked genes would control economically important traits of Eucalyptus (Grattapaglia and Kirst 2008).
