Non-Technical Summary
STRUCTURAL POLYMORPHISMS AS CAUSES OF HETEROSIS IN POPULUS
INVESTIGATORS: Steven H. Strauss, Stephen DiFazio, Brian Stanton, and Todd Rosenstiel
INSTITUTION: Oregon State University, West Virginia University, Greenwood Resources,
Portland State University
NON-TECHNICAL SUMMARY:
Natural genetic diversity within and among species is the basis of most plant breeding
programs. Breeding progress relies on variation in DNA sequences, but also on variability in the
presence and absence of genes and DNA that control gene expression, which we together refer
to as “structural polymorphisms” (SPs). The objectives of this project are to characterize the
extent of SP between and within species in cottonwood trees that are used to produce wood
and bioenergy, and examine their relationship to growth, stress tolerance, and breeding
efficiency.
OBJECTIVES:
We will study wild black cottonwoods and interspecies hybrids important in plantations in the
Pacific Northwest USA and other parts of the world. We will focus on the extent to which assay
of SPs could improve hybrid breeding compared to alternative approaches, including the use of
non-SP DNA sequence variation under newly developed “genomic selection” methods of
advanced breeding. Our preliminary work has already demonstrated that SPs are abundant
within and among species, and they are associated with phenotypic variation.
We will use phenotypic and/or genomic information from existing research trials and
studies, and also generate substantial new phenotypic and genomic information. The Populus
breeding program of GreenWood Resources (GWR), which leads in poplar breeding in the
Pacific Northwest USA, will provide F1 hybrid genotypes and phenotypic information.
APPROACH:
Our project will seeks to answer the following questions:
1) What is the extent of within- and between-species variation in SPs?
2) Are SPs associated with variation in productivity, stability of growth among plantation
environments, and temperature stresses?
3) Does knowledge of structural variation provide value beyond SNPs as part of molecular
selection during hybrid breeding?
We have engaged collaborators who are internationally known scholars and
practitioners. If successful, this project will lead to methods that can substantially increase the
efficiency and rate of genetic improvement, providing economic and environmental benefits for
growers and society.
PROJECT CONTACT:
Name: Strauss, S.H.
Phone: 541-737-6578
Fax: 541-737-1393
Email: Steve.Strauss@oregonstate.edu