QTL associations for density and diameter in Pinus radiata and the potential for marker-aided selection

Abstract

A large full-sib family of radiata pine ( Pinus radiata Donn. ex D. Don) was used for quantitative trait locus (QTL) detection and independent verification. QTL detection experiments were carried out for juvenile wood density (JWD) and stem diameter at breast height (DBH) using selective genotyping. Evenly spaced RFLP and microsatellite markers were selected from an existing linkage map. QTLs were verified in an independent set of progeny from the same family. Based on map location, at least eight QTL positions for JWD and two for DBH were detected and verified. The percent variance accounted for by the markers ranged from 0.78% to 3.58%, suggesting a genomic architecture of many genes with small effect. Two unrelated "bridging" families were chosen as candidates for marker-aided selection (MAS), and six microsatellite markers showing an association with JWD or DBH were tested in these families. Of these, four markers showed a consistent association with JWD in one or both of the bridging families. Results from this study provide a basis for MAS in P. radiata.

Identification of quantitative trait loci for wood and fibre properties in two full-sib pedigrees of Eucalyptus globulus

“…Verhaegen et al (1997) identified seven genomic regions in E. grandis/ urophylla pedigree associated with wood density. Similarly eight and nine QTLs for wood density with small effects have been reported in radiata pine (Devey et al 2004) and loblolly pine, respectively (Sewell et al 2000). Generally wood traits within species are under control of many QTLs/genes of reasonably small effect.…”

Detection and verification of quantitative trait loci for resistance to Dothistroma needle blight in Pinus radiata

“…The number of progeny per family required for QTL detection and verification in forest trees is generally thought to be quite large (Carson et al 2003a(Carson et al , 2003bDevey et al 2003). In some cases, it may be possible to use several related families of much smaller numbers to accomplish this result (Muranty 1996).…”

QTL influencing growth and wood properties in Eucalyptus globulus

“…Despite some reports of a negative phenotypic correlation between growth and wood density (MacDonald et al 1997;Wei and Borralho 1997;Costa e Silva et al 2009), the presence of independent QTL for these traits indicates that at least some components of their respective genetic control are unique to each trait. Similarly, past studies in Pinus radiata (Devey et al 2004) and E. globulus (Bundock et al 2008) each found one case of co-located QTL affecting both traits, but also several independent QTL for density (Devey et al 2004) and growth (Bundock et al 2008). Taken together, Grattapaglia et al (1996) and also used by Brondani et al (2002Brondani et al ( , 2006 b Density measured using pilodyn penetration, # linkage group, coded as reported in Bundock et al (2008) c MFA micro fibril angle, # linkage group, coded as reported in Thamarus et al (2004) d CBH stem circumference at breast height, % bark percentage weight of bark wood these findings suggest there is potential to achieve some genetic improvement in growth rate and wood property traits simultaneously.…”

“…b The proportion of the total genotypic variation explained by each QTL peak c The proportion of the total phenotypic variation explained by each QTL peak d For the co-located QTL segregating from the female parent on linkage group 5, the genotype means at a common marker are shown to enable a comparison of QTL effects, in addition to the genotype means at the QTL peak in order to show the maximum effect at each QTL differences between studies, previous QTL studies investigating wood property traits in forest trees such as eucalypt (Verhaegen et al 1997;Thamarus et al 2004;Bundock et al 2008), pine (Markussen et al 2003;Devey et al 2004) and poplar (Zhang et al 2006) have generally located several QTL with small to moderate effects for traits such as wood density, pulp yield and chemical properties, consistent with the present study. Therefore, given the above bias, it is likely that numerous QTL of small effect remain undetected, and that the genetic control of wood property traits in general is under polygenic control.…”