Ref ID: 10324
Ref Type: Note
Authors: Shepherd, M., Dieters, M. J., and Henry, R. J.
Series Title: Hot Off the Seed Bed
Pub Date: 2003
Number: 50
Edition:
Num Pages: 2
Editors:
Series Editor:
Publisher: CRC-SPF
Node: Lismore, NSW
Keywords: breeding/character/combination/conventional breeding/correlations/current/density/Douglas-fir/effect/F1/fir/gain/gene/genes/genetic/genetic improvement/genetics/germplasm/growth/Hot off the Seed Bed/hybrid/hybrids/improvement/loci/negative/new/P/parent/pine/pine hybrid/Pinus/Pinus caribaea var.hondurensis/Pinus elliotii var.elliotii/Pinus radiata/plantation/population/progeny/program/putative/QTL/quantitative/quantitative genetics/quantitative trait loci/Queensland/rate/seed/show/species/spruce/strategy/study/trait/tropical pine/wood/wood properties
Abstract: An unfavourable negative relationship between growth rate and wood density is a key issue in the genetic improvement of some of the world's major plantation species (eg. Pinus radiata, White spruce, Douglas fir, P. caribaea var. hondurensis) as simultaneous gains in both characters requires special breeding programs (Zobel and Jett 1996). An understanding of the causes of these negative genetic correlations at the gene level would allow targeted approaches to surmount this impediment. For example, where a negative correlation is due to multiple tightly linked genes, a strategy to identify correlation breakers, rare individuals within large progenies from current breeding parents, is appropriate. However, where a negative correlation is a consequence of pleiotrophy (a single gene controlling more than one character), a strategy to find new genes that ameliorate the correlation is more appropriate. Recent results from quantitative trait loci (QTL) mapping studies in the F1 hybrid of P. elliottii var. elliottii X P. caribaea var. caribaea (PEE X PCH) show a general lack of co-localisation of putative QTL for density and growth. The independence of these gene effects is consistent with a quantitative genetics studies of these traits in this hybrid (Kain 2002). This suggests that strategies to further improve wood density in the PEE X PCH hybrid, without deterioration in growth rates, should be possible by seeking favourable gene combinations within the existing breeding population without recourse to new germplasm and new genes
Notes: Entered by Mervyn Shepherd (30/05/2003)
Address:
Reprint: In File
Program: SPF Genetic Improvement
Project:
Deliverable: A7-3
Confidentiality: Confidential to Core and Supporting Partners
Availability: Authors
Report: Annual Report 2002/3