Candidate gene-based association mapping of growth and wood quality traits in Eucalyptus globulus Labill

Background The identification of polymorphisms that underlie complex phenotypic traits presents new and exciting challenges to molecular genetics. Association mapping, which uses linkage disequilibrium (LD) to map trait variation with nucleotide polymorphisms, has proved suited for this purpose in outcrossed tree species. Association mapping can be undertaken either at a candidate gene level or at the whole-genome level however; until sufficiently dense marker assays are developed the candidate gene approach will remain the most effective way of dissecting complex traits in tree species. To date, this approach has led to the identification of several quantitative trait nucleotides (QTN) that associate with a variety of breeding traits including, early wood specific gravity, percentage latewood [1], microfibril angle [2], cellulose [3]and carbon isotope discrimination [4].