Quantitative trait locus (QTL) analysis of growth and vegetative propagation traits in Eucalyptus nitens full-sib families

Abstract

Tree growth and vegetative propagation are complex but important traits under selection in many tree improvement programmes. To understand the genetic control of these traits, we conducted a quantitative trait locus (QTL) study in three full-sib families of Eucalyptus nitens growing at two different sites. One family growing at Ridgley, Tasmania had 300 progeny and two clonally replicated families growing at Mt. Gambier, South Australia had 327 and 210 progeny. Tree growth was measured over several years at both sites and percentages of roots produced by either stem cuttings or tissue culture were assessed in the two Mt. Gambier families. Linkage analysis of growth traits revealed several QTLs for later year traits but few for early year traits, reflecting temporal differences in the heritabilities of these traits. Two growth QTL positions, one on LG8 and another on LG11 were common between the Ridgley and Mt. Gambier families. Four QTLs were observed for each of the two vegetative propagation methods. Two QTLs for vegetative propagation on LG7 and LG11 were validated in the second family at Mt. Gambier. These results suggest that growth and vegetative propagation traits are controlled by several small effect loci. The QTLs identified in this study are useful starting points for identifying candidate genes using the Eucalyptus grandis genome sequence.

Quantitative trait locus analysis of leaf morphological characters, yield-related traits, and secondary metabolite contents in Eucommia ulmoides

“…Furthermore, the clustering of QTLs controlling height and basal diameter has been observed in the same mapping population of E. ulmoides (Li et al, 2014c). In most cases, no clear patterns among phenotypic correlations have been found to coincide with the co-locating QTLs (Tsarouhas et al, 2002;Gailing, 2008;Freeman et al, 2009;Thumma et al, 2010;Li et al, 2014c). In the present study, we found that 16 QTLs were unique to specific traits (Figure 2).…”

“…Previous QTL studies on main crops have frequently detected regions of the genome that contain clusters of QTLs for highly correlative traits (Zeng et al, 2009;Avia et al, 2013;Bian et al, 2013). Clusters of QTLs were also observed for growth traits and various leaf traits in poplar (Bradshaw and Stettler, 1995;Wu et al, 1997), for wood properties and growth traits in the genus Eucalyptus (Verhaegen et al, 1997;Freeman et al, 2009;Thumma et al, 2010), for growth traits in Salix (Tsarouhas et al, 2002;Ronnberg-Wastljung et al, 2005), for leaf morphological characters in European beech (Scalfi et al, 2004) and oak (Gailing, 2008;Gailing et al, 2013), and for chemical compositions in peach (Eduardo et al, 2013) and oil palm (Montoya et al, 2013). Furthermore, the clustering of QTLs controlling height and basal diameter has been observed in the same mapping population of E. ulmoides (Li et al, 2014c).…”

QTL mapping for fruit quality in Citrus using DArTseq markers

“…This approach was possible due to the existence of reference genome sequence available or when common markers exist between the different linkage maps [46]. Figure 4 shows the BLASTN results, in which essentially all the LGs were found to have full synteny with the reference genome used, except for markers that were unassigned to a chromosome (chromosome Un - Chr unassigned) or those that were not present in the genome of Citrus sinensis (Chr N).

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Tissue Culture of Corymbia and Eucalyptus

“…Much research on eucalypt somatic embryogenesis has focused on species, particularly E. globulus and its related species, E. dunnii and E. nitens, that are difficult to propagate from cuttings [14,27,29,[32][33][34].…”