Quantitative trait locus analysis of growth and wood density in an interspecific pseudo-backcross population of Eucalyptus grandis x E. urophylla

Background F1 hybrids of E. grandis and E. urophylla are commonly grown for pulp and paper production in clonal plantations in tropical and subtropical regions. Improving tree growth [1]and wood quality [2]are important objectives in eucalypt breeding programmes. The efficiency of selection for these traits can be enhanced by molecular breeding approaches enabled by high-throughput, genome-wide genotyping technologies and the recent completion of a reference genome sequence for Eucalyptus (E. grandis V1.0, JGI, http://www.phytozome.net). In this context, interspecific hybrid pedigrees are valuable for quantitative trait locus (QTL) dissection in Eucalyptus as there is abundant interspecific variation in such pedigrees. Breeding for wood property traits is mainly focussed on increasing pulp yield per hectare, reducing wood specific consumption (WSC) and increasing the efficiency of downstream processing by the pulp and paper industry. In this study, we are characterizing the genetic architecture of growth and wood quality traits in an interspecific pseudo-backcross mapping population of an F1 hybrid of E. grandis and E. urophylla.