Biotechnology in the Southern Research Station: A Problem Analysis 

Biotechnology in the Southern 

Research Station: A Problem 

Analysis 

F.E. Bridgwater and C.D. Nelson

United States

Department of

Agriculture

Forest Service

Southern

Research Station

General Technical 

Report SRS–96
General Technical Report SRS-GTR-96

The Authors

F.E. Bridgwater, Research Geneticist, USDA Forest Service, 

Southern Research Station, Research Triangle Park, NC 27709;

C.D. Nelson, Research Geneticist and Project Leader, USDA Forest 

Service, Southern Research Station, Saucier, MS 39574–9344

September 2006

Southern Research Station

P.O. Box 2680

Asheville, NC 28802

In Collaboration with the Institute of Forest Biotechnology

Raleigh, NC 27606
Biotechnology in the Southern Research Station: A Problem Analysis 

Abstract

We provide an analysis of opportunities and challenges for biotechnology in forest 

research in the southern United States. Four major areas of biotechnology were identified 

and described and then rated for priority among three groups of researchers—private 

sector, public sector, and the USDA Forest Service, Southern Research Station (SRS). 

The four areas of biotechnology were vegetative propagation, genetic transformation/

modification, genomics/bioinformatics, and molecular marker applications. We concluded 

that these three groups have different research priorities with respect to biotechnology and 

that these differences complement each other. In particular, the SRS should continue its 

work in molecular marker technology development for applications in tree improvement, 

conservation genetics, forest health, and basic science. Also, the SRS should increase 

its efforts in genomics/bioinformatics while decreasing its research on vegetative 

propagation. Finally, the SRS should work on assessing the potential risks and impacts of 

planting and managing clones and/or genetically modified trees.

Keywords: Bioinformatics, clonal forestry, forest biotechnology research, genetic 

transformation/modification, genomics, marker-assisted selection (MAs), molecular 

markers, vegetative propagation.
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General Technical Report SRS-GTR-96
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Biotechnology in the Southern Research Station: A Problem Analysis 

Contents

 1 Executive Summary

 3 Recommendations

 3 Introduction

 6 Recommendations for the Southern Research Station

 7 Opportunities for the Application of Biotechnology in Forestry

 7 Vegetative Propagation

 8 Vegetative Propagation Is an Important Tool in Experimentation

 8 The Future of Clonal Forestry Is Near

 9 Molecular Marker Applications

11 Genomics and Bioinformatics

16 Genetic Transformation/Modification

19 Research Status and Opportunities for the Southern Research Station

23 Summary of Recommendations

23 Literature Cited

32 Glossary
General Technical Report SRS-GTR-96

Executive Summary

Four major areas of forest biotechnology research—vegetative 

propagation, molecular marker applications, genomics/

bioinformatics, and genetic transformation/modification—have 

different research priorities for private- and public-sector clients. The 

forest industry clearly favors research that promises to increase 

productivity and profitability. Private forest industries that have 

invested heavily in vegetative propagation and gene transformation 

research hope to commercialize these technologies. Vegetative 

propagation and gene transformation techniques are also important 

research tools in genetics studies, and both of these technologies, 

especially vegetative propagation, are sufficiently well developed 

to be useful research tools. Molecular marker applications, 

genomics, and bioinformatics are important supporting research 

areas for commercial applications, but vegetative propagation 

and gene transformation technology are the critical elements for 

commercialization. Public- and private-sector clients are likely to 

support research to sustain ecosystems, restore species, and 

preserve threatened and endangered species. Thus, both client 

groups are interested in molecular marker studies of population 

structure and dynamics and in genomics research on genes 

controlling traits like disease and insect resistance. Genomic 

studies and bioinformatic analyses provide a foundation for 

understanding the genetic basis for traits of commercial interest, as 

well as traits that enhance forest health and sustainability. 

Publicly funded research should support both public- and 

private-sector clients. The central question is how to prioritize 

publicly funded research in the Southern Research Station (SRS) 

among the four biotechnology research areas. Private companies 

have developed efficacious vegetative propagation and gene 

transformation technology, and both technologies may soon be 

available for public and private organizations that want to capitalize 

on genetically modified (GM) trees. However, the benefits from 

these technologies will accrue primarily to private forest industry. 

Developing these techniques in publicly funded labs would 
Biotechnology in the Southern Research Station: A Problem Analysis 

require duplicating a substantial amount of proprietary research. 

Furthermore, citizens’ concerns may prevent planting clones or GM 

trees on public lands in all but a few circumstances where genetic 

modification and/or vegetative propagation are the only means to 

achieve the common goal. For example, foresters may deploy GM 

trees resistant to a new disease or insect pest when traditional 

breeding programs would take too long to protect adequately a 

species at risk. Publicly funded research should develop methods 

to evaluate and monitor the risks of deploying clones and GM trees 

since policymakers will require unbiased information on which to 

base regulation.

Molecular marker applications address many questions 

important to both public- and private-sector clients. Many 

applications have the potential to increase forest productivity and 

health. Molecular markers can enhance the efficiency of breeding 

programs through marker-assisted selection (MAS). They can also 

be used to deploy trees with known resistance to diseases like 

fusiform rust (Cronartium quercuum f. sp. fusiforme) in high hazard 

areas and to monitor genetic diversity as it changes in commercial 

breeding populations. Molecular markers permit us rapid inference 

of genetic structure and mating patterns. Such population 

information is important for commercial species, but is especially 

valuable for policymakers considering the fate of threatened 

and endangered species. Molecular markers may also resolve 

taxonomic issues for conservation prescriptions and form the basis 

for constructing genomic maps, which add value to many of these 

analyses. Because of the broad application for both public and 

private clients, molecular marker applications are a high research 

priority in the SRS. Furthermore, molecular marker application is 

fast and relatively inexpensive biotechnology.

Genomics studies and bioinformatic analyses explain the 

regulation and expression of genes. Structural genomics involves 

genetic and physical mapping and large-scale DNA sequencing that 

clarify the overall organization of the genome. Functional genomics 

involves large-scale gene analysis to discover key genes and 
General Technical Report SRS-GTR-96

regulatory networks. Bioinformatics integrates data from structural 

and functional genomics research. With increasing capability in 

genomics and bioinformatics, the SRS can apply the Populus

genome sequence and sequences from other plant species in 

its own research. Discovering genes related to forest productivity 

and health and understanding their regulation will be critical for 

addressing emerging research issues. Both public and private 

groups can use genomics and bioinformatics to understand the 

genetic basis for wood formation, disease and insect resistance, 

flowering, and stress response.

Recommendations

The SRS should continue to emphasize the application of 

molecular marker technology to a broad range of questions about 

forest genetics and tree improvement and should expand its 

capability in genomics research and bioinformatics. 

The SRS should deemphasize its own research in vegetative 

propagation and gene transformation methods, but should seek 

opportunities to support the research of others in these areas. 

The SRS should evaluate the risks of clonal and GM tree 

deployment.

Introduction

The U.S. Department of Agriculture Forest Service must align 

its research priorities in forest biotechnology to meet the needs of 

both public and private forest landowners. Their interests overlap 

significantly in many areas, but we perceive a dichotomy in the 

hierarchy of importance that both groups give to different research 

areas. The private sector is likely to support research to increase 

profits, while the public sector supports research on ecosystem 

sustainability or restoration. This report will identify and prioritize 

research that both groups need over the next 5 years. It will provide 

a broad overview of currently available biotechnology for forest 

research and serve as a planning tool for prioritizing biotechnology 

research within the SRS. 
Biotechnology in the Southern Research Station: A Problem Analysis 

Two groups of landowners have different land management 

objectives. Currently, the South has about 200 million acres of 

forests. The Forest Service manages about 6 percent, other 

Government agencies 5 percent, forest industries 19 percent, and 

nonindustrial private forest (NIPF) landowners 70 percent (Wear 

and Greis 2002). The South produces about 60 percent of the 

Nation’s timber products, and a large share (41 percent) of the net 

annual growth comes from the small proportion (11 percent) of 

growing-stock volume in non-Federal plantations (Wear and Greis 

2002). Industry owns 54 percent and NIPF landowners own 40 

percent of these plantations, the majority of which are of loblolly 

(Pinus taeda L.) and slash (P. elliottii Engelm.) pines. By 2040, the 

total acreage of pine plantations is forecast to rise by 67 percent 

(Wear and Greis 2002).

Virtually all of the 1.2 billion loblolly pine and 150 million 

slash pine seedlings planted each year are genetically improved 

(McKeand and others 2003). Private forest companies, three 

southern universities, and all Southern State forestry organizations 

conduct cooperative breeding programs for loblolly and slash pine. 

The Forest Service—SRS and Region 8 of the National Forest 

System (NFS)—also support research in tree improvement and 

genetics of these two important commodity crops as well as other 

species of pines and hardwoods.

The benefits of genetic improvement are available to both 

private forest industry and public growers who purchase seedlings 

from private and State nurseries. Biotechnology research promises 

to increase productivity and add value to commodity crops. The 

private sector (to include those NIPF landowners whose primary 

objective is timber production) wants research on technologies that 

increase the profits and long-term productivity of plantation forestry.

Population growth threatens rare forest communities, and rare 

plant and animal species. The Southeast has the highest number 

of endangered ecosystems of any region in the country, and 30 

percent of these are critically endangered (Wear and Greis 2002). 
General Technical Report SRS-GTR-96

Laws protect many of these communities, plants, and animals 

on public and private lands, and every Southern State has both 

threatened and endangered species (Wear and Greis 2002). Many 

species at risk occur on public lands, which represent a relatively 

small percentage of forested land in the South (Wear and Greis 

2002). Government land is an important component in preserving 

endangered species. To preserve sensitive ecosystems and the 

plant and animal species dependent upon them, the forest industry 

has transferred ownership of some critical natural lands to public or 

private conservation organizations (Wear and Greis 2002). Clearly, 

on publicly owned lands, there must be different emphases among 

management objectives, including the status of both commodity 

and noncommodity species.

A dichotomy of land management objectives creates two different 

client groups for biotechnology research in the South. Although 

many areas of biotechnology research overlap, private landowners 

are more likely to favor research to increase forest productivity and/

or profitability. A broader constituency representing the public sector 

favors research on both commodity and noncommodity species with 

the aim of ecosystem sustainability or restoration.

We define biotechnology as any technological application 

that uses biological systems, living organisms, or derivatives 

thereof to make or modify products or processes for specific use. 

Biotechnology in forestry generally falls into one of four main topics: 

(1) vegetative propagation, (2) molecular marker applications, 

(3) genomics/bioinformatics, and (4) genetic transformation/

modification. Private forest owners and public forest managers 

have different priorities for research. Forest industry is primarily 

interested in increasing profitability while maintaining sustainability 

of productivity for commodity crops. The public sector is primarily 

interested in sustaining or restoring ecosystems and species at 

risk. The four main topics for biotechnology research are ranked 

for public- and private-sector users and for the SRS. Biotechnology 

research areas prioritized for public and private sectors and for the 

SRS are:
Biotechnology in the Southern Research Station: A Problem Analysis 

Research priority

Biotechnology research area Private Public SRS

Vegetative propagation 1 3 4

Genetic transformation/modification 2 4 3

Genomics/bioinformatics 3 2 2

Molecular marker applications 4 1 1

The potential for application to both public- and privatesector clients dictates the general rationale for the SRS ranking. 

Supporting analysis for these rankings appears in the body of 

this analysis. Both public and private constituents benefit from 

research in molecular marker applications and in genomics and 

bioinformatics. Vegetative propagation and genetic transformation/

modification technology provide useful research tools for ecosystem 

sustainability and forest health, such as clonal propagation of 

threatened or endangered species. However, the benefits of largescale applications will accrue primarily to private-sector landowners. 

Recommendations for the Southern 

Research Station

The SRS should continue to develop molecular genetic marker 

technology for a broad range of applications in tree improvement, 

conservation genetics, forest health, and basic forest genetics. 

The SRS should significantly increase research in genomics 

and bioinformatics to take advantage of new data from complete 

genome sequences and gene discovery projects on model plants 

and forest trees.

The SRS should deemphasize research into vegetative 

propagation methods. The benefits from successfully implementing 

vegetative propagation for commodity species in the South will 

accrue primarily to the private sector, which has a significant lead 

in developing this technology. A significant Federal effort in this 

area would duplicate proprietary research already done by private 

industry. Vegetative propagation techniques are already sufficient 

for use in research. 
General Technical Report SRS-GTR-96

The SRS should assess the risks and potential impacts of clonal 

and GM tree deployment on southern forest ecosystems. It should 

not study transformation methods, per se, because other groups 

are better positioned to conduct this research. 

Although vegetative propagation and genetic transformation/

modification technology are not primary objectives, publicly 

available methods for these would be valuable. Thus, the SRS 

should seek opportunities to support such research by others.

Opportunities for the Application of 

Biotechnology in Forestry

Vegetative Propagation

Currently, the most significant barrier to clonal forestry and the 

application of GM technology is the economic production of large 

numbers of vegetative propagules from trees old enough to have 

been adequately tested. For decades, forest tree improvement 

programs have used vegetative propagation in its simplest forms 

(grafting and rooting cuttings). But large-scale reforestation by 

vegetative propagation is limited to species for which rooting 

cuttings is easy for mature trees or for which rejuvenation 

techniques are available.

For two primary reasons, finding an economical method to 

produce clones of tested genotypes is a high priority for foresters 

who want to increase profits through biotechnology. First, the 

ability to produce clones of mature genotypes of loblolly and slash 

pines with proven genetic value would increase economic returns 

from traditional tree improvement programs. Current methods of 

producing large numbers of rooted cuttings permit breeders to 

capitalize on genetic differences among families by planting rooted 

cuttings from immature and untested progenies of tested parents. 

This method is genetically equivalent to producing large numbers 

of control-pollinated seeds by conventional means (Frampton and 

others 1999) while cloning the best individual in the best family 

maximizes the realized gains from these traditional programs 

(Frampton and others 1999). Second, capitalizing on genetic 
Biotechnology in the Southern Research Station: A Problem Analysis 

transformation/modification technology depends on transforming 

tested genotypes and transforming these in large numbers. 

Successful GM clones are proven genotypes into which genes from 

the same or different species have been introduced. 

Vegetative Propagation Is an Important 

Tool in Experimentation

Cloning individuals to control the inherent variation among 

genotypes is a powerful experimental tool (Loegering 1984). For 

example, we need to understand the underlying genetic interactions 

between host and pathogen in fusiform rust disease in loblolly 

and slash pines (Nance and others 1992). Although controlling 

fusiform rust infection has significant economic benefits, cloning 

can increase the efficiency of experiments (Shaw and Hood 1985). 

Cloning is more feasible for experimentation than for producing 

commodity crops since success rates and economic returns are 

less important. In fact, experiments currently use clones of several 

species, including loblolly and slash pines, that are difficult to 

propagate vegetatively in large numbers (Anon. 2000). Vegetative 

propagation already occurs at a practical scale and cost for 

experimentation. Also, because the ability to clone is not required to 

address many important questions about forest ecosystems, it is of 

secondary importance for public-sector research.

The Future of Clonal Forestry Is Near

The successful development of micropropagation is the future 

of clonal forestry, especially for species that root poorly as older 

trees. The most promising technique, somatic embryogenesis (SE), 

produces clonal lines from immature seeds. SE is the process 

of culturing explants from immature zygotic embryos to produce 

embryogenic masses from which somatic embryos are produced 

and germinated. Emblings thus generated, i.e., somatic seedlings, 

are genetically identical members of a clone of the original 

embryo. Successful SE for several species, including the southern 

pines, is currently under commercial development. Coupled with 

cryopreservation while genotypes are being tested, SE is the most 

promising method for clonal forestry in many species (Vendrame 

and others 2001).
General Technical Report SRS-GTR-96

However, substantial barriers remain to successful clonal 

forestry in the southern pines (Pullman and others 2003). In the 

South at present, vegetative propagules of selected genotypes are 

being planted only in experimental trials. Not every tested genotype 

can be successfully vegetatively propagated with current SE 

technology, and the success of maintaining or restoring juvenility 

in stock plants for rooted cutting production of clones is still under 

study. Currently, the cost of producing vegetative propagules 

remains high enough to deter both rooted cuttings and SE. 

Furthermore, researchers have not adequately assessed the risks 

of clonal deployment.

Molecular Marker Applications

Molecular genetic markers are genes or other identifiable 

portions of DNA with traceable inheritance. Markers have many 

applications in forest genetics and tree improvement. A researcher 

can select among several kinds of DNA markers with different 

attributes that best suit an experiment (reviewed in Cervera 

and others 1997; Nelson, in press; Wang and Szmidt 2001). As 

gene-sequence information becomes more readily available for 

forest trees, sophisticated marker techniques developed for other 

organisms will aid forest genetics (Harry and others 1998). These 

new markers, called expressed sequence tag polymorphisms 

(ESTP or EST), derive from complementary DNA (cDNA) libraries 

that represent expressed genes. EST markers provide most of 

the attributes desired in molecular markers. More recently, single 

nucleotide polymorphisms (SNP) have been developed in forest 

trees (summarized in Plomion and others 2003). Abundant SNPs 

may have application in genetic mapping studies that do not rely 

on pedigree structure such as mapping by association or linkage 

disequilibrium mapping (Kwok 2001, Roses 2000).

Molecular genetic markers have applications in “fingerprinting” 

genotypes; DNA sequence variations detected by examination 

of multiple markers produce a unique identifier for a genotype. 

Fingerprinting unambiguously identifies specific genotypes and can 

also provide evidence for the origin of a genotype with respect to 
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Biotechnology in the Southern Research Station: A Problem Analysis 

provenance and species as well as species hybrids. A common use 

in tree improvement is to certify the parentage of controlled crosses 

(Lin and others 1997). All of these uses have practical applications 

in forest management. 

Molecular genetic markers provide information about 

populations. Markers are useful for estimating population genetic 

structure, level of inbreeding, gene flow, and type of mating 

system (Adams and others 1990). They also provide phylogenetic 

(Tsumura and others 1996) and paleobotanical (Marshall and 

others 2002) insights. Genetic markers can produce population 

genetics information more quickly than common garden studies. 

The combination of markers and common garden studies such 

as seed source or provenance tests provides the most powerful 

information for understanding population genetic structure, mating 

system, and gene flow. However, in situations requiring rapid 

decisions about the conservation or management of species at 

risk, genetic markers alone provide timely and useful information 

for policymakers and forest managers. Genetic markers can also 

resolve taxonomic questions to determine appropriate conservation 

prescriptions (Gordon and Kubisiak 1998).

Molecular genetic markers may directly enhance traditional 

breeding. Statistical associations between markers and genes 

can be made for traits of interest. Subsequently, the presence 

or absence of markers can indicate the presence or absence of 

the desired gene. Using markers to guide selection and breeding 

in traditional tree-breeding programs is termed MAS (Williams 

and Neale 1992). Although the concept is straightforward, the 

application of MAS is problematical and is not routinely applied 

in forestry because the conditions are restrictive for economic 

viability and economic success is not assured (Byram 2000). 

However, genetic markers can direct planting decisions for loblolly 

pine families that carry major genes for resistance to fusiform 

rust (Wilcox and others 1996). Markers are also an effective way 

to monitor genetic diversity in tree-improvement programs as 

they move through successive cycles of selection and breeding 

(Williams and Hamrick 1996).
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General Technical Report SRS-GTR-96

Molecular genetic markers are valuable in maintaining forest 

health. Used to determine the origin of introduced pathogens or 

insects, markers can reduce the possibility of future introductions. 

As diagnostic tools, molecular markers can be used to detect trace 

amounts of pathogens in samples (Blomquist and Kubisiak 2003) 

and measure gene flow among pathogen populations providing 

a means to help manage risk to forest ecosystems (Kinloch and 

others 1998, Klopfenstein and others 2001). As we learn more 

about the genetic basis for disease development in host:pathogen 

systems (Kinloch and others 1998), it will become possible to 

detect and monitor resistance and virulence genes in the host and 

pathogen populations, thus providing a valuable tool for controlling 

forest diseases. 

Genomics and Bioinformatics

Genomics permits geneticists to make the connection between 

genes and phenotypes. Genomics is the study of genomes, the 

total DNA and RNA in cells. Genetics is the study of single genes 

inferring their presence and effect from phenotypes. Genomics 

considers genes as a complete, dynamic system as they interact 

with one another in different tissues and over time, linking gene 

expression to phenotype and allowing phenotype to be predicted 

from genotype. Structural genomics studies genome organization. 

Functional genomics studies gene regulation and expression, 

and their role in cell function and phenotype determination. 

Bioinformatics is necessary to manage and analyze the large, 

complex datasets that result from structural and functional 

genomics research.

Genetic maps provide a framework for integrating diverse types 

of genetic information. Forest geneticists have used molecular 

markers for decades (Neale and Harry 1994). Several new types 

of markers have attributes that suit different applications, but all 

markers are cumulatively informative. Positioning all available 

markers on a single reference map integrates past and future 

genetic maps (Sewell and others 1999). Such a reference map 
12

Biotechnology in the Southern Research Station: A Problem Analysis 

shows how genomes are organized and provides insight into how 

they function. These maps are also critical components of MAS, 

map-based cloning, and gene discovery projects.

Genetic linkage maps rely on estimating crossover, i.e., 

recombination, frequencies during meiosis. Genes located near 

one another are linked since they tend to be inherited together. 

Because crossing over occurs, the crossover frequencies can 

serve as surrogates to order markers into linkage groups and 

construct maps of their relative positions within these groups (Hartl 

and Jones 2001, chapter 5). Physical mapping measures the 

number of base pairs of DNA between markers rather relying on 

recombination frequency. Physical maps are based on sequences 

of overlapping segments of DNA (contigs) that provide measures 

of distances (base pairs) between probes or markers within the 

contigs. Physical mapping is done by hybridizing probes against a 

library of DNA clones that are subintervals of a larger piece of DNA. 

If a clone contains a sequence complementary to the probe, the 

clone and probe will hybridize and produce a signal. By comparing 

and ordering the probe sequences, it is possible to determine the 

order of probes (and their DNA complements) in the larger piece of 

DNA. This information can identify genes and their relative positions 

along chromosomes. Physical maps can also be visualized when 

specific chromosome segments are labeled with compounds that 

can be seen with a light microscope (Hartl and Jones 2001, chapter 

13). There is a current effort to map Populus using bacterial artificial 

chromosome (BAC) libraries (U.S. Department of the Interior, Oak 

Ridge National Laboratory 2003).

Genetic linkage mapping shows the relative positions of 

chromosomal segments and genes, but does not identify the 

exact physical location of the segments on chromosomes. Other 

techniques do permit the visualization of the physical location of 

segments on chromosomes such as fluorescent in situ hybridization 

(FISH). FISH techniques use genomic probes, which are singlestranded DNA or RNA of a specific base sequence labeled in 

some way so they can be visualized; FISH probes are labeled with 
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General Technical Report SRS-GTR-96

fluorescing dyes, hence the name. Probes hybridize when they pair 

with their complementary strands of DNA to form a double-stranded 

molecule. Once the probes have hybridized, the physical location 

of the sequences that complement the sequences of the probes 

can be visualized, providing a karyotype that depicts an individual’s 

chromosomes arranged in a standard format showing the number, 

size, and shape of each chromosome (Doudrick and others 1995). 

Physical mapping has several potential advantages over linkage 

mapping. First, there are genomic regions in which little crossing 

over occurs. Since linkage maps rely on crossing over, physical 

maps are required to study these chromosomal regions. Second, as 

genetic distance gets smaller, crossover rates decline. Thus, very 

large populations of individuals must be mapped to locate genes 

separated by small genetic distances. Physical mapping does not 

require recombination, so it can provide useful information from a 

single genotype.

Map-based cloning can be used to identify and clone a gene of 

interest. Map-based cloning requires a sufficiently dense genetic 

map to locate markers flanking a genomic region that codes for a 

phenotype of interest. The region flanked by the markers is then 

isolated, sequenced, and examined for differences in individual 

genes expressing different phenotypes. In addition to a dense 

genetic map, a good physical map is invaluable to guide the “walk” 

to the gene, especially in large, complex genomes such as Pinus 

and Populus. Map-based cloning is relatively simple in plants like 

Arabidopsis where there is a wealth of genetic and physical map 

information available (Jander and others 2000). Map-based cloning 

may soon be feasible for Populus, as it is the first tree genome to be 

sequenced (DOE Joint Genome Institute 2002) and it has a good 

physical map based on BAC contigs. Again, map-based cloning is 

problematical for conifers such as Pinus due to their large, complex 

genomes (Murray 1998) and because a complete sequence awaits 

improvements in technology (Lev-Yadun and Sederoff 2000). 

However, new technology may significantly ease the task (Peterson 

and others 2002).
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Biotechnology in the Southern Research Station: A Problem Analysis 

Sequence tagged sites (STS) offer a way to physically map 

genes. STSs are DNA sequences that occur once in a haploid 

genome. Once they have been sequenced, appropriate primers 

can be designed that permit their detection by polymerase chain 

reaction amplification (Hartl and Jones 2001, chapter 13), which 

amplifies a DNA sequence inclusive of the primers. Given adequate 

numbers and distribution in the genome, STSs can be used to 

assemble contigs of BAC clones to provide a physical map of the 

markers. If STSs are derived from DNA of expressed genes, they 

are even more valuable as they tag a specific gene. An EST can be 

used to assemble contigs of expressed regions if they are unique 

and do not belong to a gene family with more than one gene of the 

same, or similar, sequence. ESTs may also be used to construct 

microarray experiments to couple gene expression profiles with 

phenotypes (Sterky and others 1998).

A candidate gene approach offers another method for gene 

discovery and studying their function in large genomes. This 

approach compares the sequence homology of genes that are 

expressed in tissues of interest with proteins of known or predicted 

function. Gene expression describes the transcription of DNA

into messenger RNA (mRNA) that is subsequently translated into 

proteins that perform cell functions. Thus, the kinds and amounts of 

mRNA produced by a cell reflect which genes are expressed and 

permit the study of how the cell responds to different situations. 

The process begins with isolating mRNA from the appropriate 

tissue, such as developing xylem to study wood formation, and 

reverse transcribing them into cDNA. After random selection, cDNA

clones are partially sequenced to produce ESTs whose sequences 

are compared to sequences of proteins of known or predicted 

function in public databases. As the sequences available in public 

databases increase, the candidate gene approach will assume 

greater importance in genomics studies of forest trees. To enable 

the genetic transformation/modification of existing commercial 

lines of forest trees, gene discovery projects in progress try to 

identify and map the genes active during different stages of xylem 

formation (Chen and others 2001, Lev-Yadun and Sederoff 2000) 
15

General Technical Report SRS-GTR-96

and flowering (Rottmann and others 2000), among other traits. 

Hundreds of thousands of ESTs for many species (for a list, see 

The Center for the Advancement of Genomics 2000) are stored 

in databases accessible through the Internet (National Center for 

Biotechnology 2003, Pittsburgh Supercomputing Center 1999). 

These sequences represent an unprecedented opportunity for 

forest geneticists, and our challenge is to use this information 

effectively.

Microarray and sequencing technology enable the simultaneous 

study of the expression of many genes. With this technology, we 

can determine not only whether genes are switched “on” or “off,” but 

also the degree to which they are expressed. Microarrays are solid 

supports made of various materials upon which an organized array 

of spots of genomic DNA, cDNA, or oligonucleotides (DNA usually 

< 40 base pairs) is immobilized. The microarray is coincubated 

with cDNA probes derived from tissues of interest and labeled with 

a fluorescent tag. The fluorescent tag enables the construction of 

a digital image of the array that varies depending on the amount 

of cDNA hybridized with the target DNAs on the microarray. Thus, 

the greater the fluorescence, the greater the gene expression for 

a given sample. By using different colors of fluorescent tags, a 

single experiment can differentiate more than one sample (Hartl 

and Jones 2001, chapter 13). For example, microarray expression 

analysis with different colored tags can label diseased and healthy 

tissue, and the expression of each sequence can be quantified on 

each immobilized DNA spot (Morse and others 2004). Researchers 

can determine which sequences are expressed more or less under 

different conditions, e.g., stressed and nonstressed, and infer 

which sequences are involved in defending against stresses (Wu 

and others 1999). Conceptually, this same technology identifies 

which genes are involved in any other processes. Gene expression 

is dynamic and varies among different tissues and over time, so 

the experimental design of microarray experiments must adapt 

accordingly. Microarray mutation analysis can detect small changes 

in DNA sequence such as SNPs. The SNP expression patterns 

generated are powerful molecular markers (Kwok 2001). 
16

Biotechnology in the Southern Research Station: A Problem Analysis 

The very large databases generated from genomics studies 

require a capability in bioinformatics. Bioinformatics employs 

computational science to manipulate the huge databases 

containing nucleotide and amino acid sequences and associated 

information. Using bioinformatics, researchers can efficiently assess 

relationships among members of very large datasets. With these 

computational tools, they can locate genes within sequences, 

generate computerized genomic maps, and compare candidate 

genes with similar sequences from organisms that have been 

better characterized. A viable bioinformatics capability is a critical 

component of genomics research.

Genetic Transformation/Modification

Genetic transformation/modification has the potential to confer 

significant genetic changes in plants more rapidly than conventional 

breeding. Genetic transformation/modification is the introduction 

of a heterologous (foreign) or homologous (conspecific) gene or 

genes into a plant’s genome by artificial means. Traditional breeding 

methods take many generations of selective mating to produce 

changes in trees that genetic engineering may accomplish in a few 

years. Introducing new genes into an existing genetic background 

would clearly benefit growers interested in improving profits from 

forest trees.

Transgenic trees have important commercial applications. 

Populus have been transformed to incorporate genes from a 

natural insect pathogen, Bacillus thuringiensis, to confer resistance 

to insects (McCown and others 1991) and to modify wood 

composition (Hu and others 1999). Extending these results to more 

commercially important species, e.g. loblolly pine, may provide a 

large economic impact. Biolistics (Charest and others 1997) can 

produce GM trees, and other organisms such as Agrobacterium

(Kim and others 1997) can serve as vectors for introducing new 

genes. Efficient transformation systems that include vertically 

integrated gene function testing can test novel gene constructs in 

forest trees (Hinchee and others 2003). Large numbers of promising 

gene constructs are first screened in an easily transformed model 
17

General Technical Report SRS-GTR-96

species, such as Populus. Promising constructs are then used 

to transform more intractable, but economically important, such 

as Pinus or Eucalyptus spp. In the near future, the technology 

to produce transgenic southern pines will become more efficient 

(Connett and others 2002). 

 There is significant public debate about planting GM trees. 

In British Columbia and Alberta, citizens’ objections to planting 

GM trees are so great that moratoria have been adopted or are 

pending (British Columbia Ministry of Forests 2000). In Europe, 

a moratorium on planting GM crops is effectively in place 

(McCord and Gartland 2002). Such moratoria may end if public 

perception changes. At present, the United States may not permit 

the planting of GM trees, particularly on public lands. In May 

2003, a “Stakeholder Forum on Biotechnology,” convened by the 

Pew Initiative on Food and Biotechnology, “generally agreed to 

outcomes, principles, and components for a regulatory system 

for agricultural biotechnology that protects public health and the 

environment” (Pew Initiative on Food and Biotechnology 2003). 

However, the forum was unable to reach consensus on the “full 

range of issues in sufficient detail” on a package of regulatory 

reforms (Pew Initiative on Food and Biotechnology 2003). The U.S. 

Government retains an interest in developing consensus on policies 

regarding the use of biotechnology in agriculture. Thus, an advisory 

committee to examine the long-term impacts of biotechnology on 

the U.S. food and agriculture system and provide guidance to the 

U.S. Department of Agriculture on pressing individual issues was 

established by the Secretary of Agriculture (National Archives and 

Records Administration 2003). 

Policymakers need sound science upon which to base their 

decisions. The primary risk of planting GM trees is the unknown 

consequence of GM trees mating with undomesticated trees. Novel 

genes, such as those carrying insect resistance, will likely escape 

into wild tree populations with unknown impacts on both target and 

nontarget species. Most domesticated crops will hybridize with their 

cross-compatible wild relatives (Ellstrand and others 1999). Since 
18

Biotechnology in the Southern Research Station: A Problem Analysis 

genetically improved forest trees are only one to a few generations 

of breeding and selection removed from undomesticated relatives, 

they will certainly hybridize. If efforts to genetically modify trees 

reduce or prevent flowering, this concern may be ameliorated. 

However, some scientists fear that adverse effects may surface in 

50 to 100 years (Kaiser 2001). Since many GM organisms are not 

regulated after they are commercialized, private industry, which 

will most benefit from their use, may not take adequate steps to 

contain and monitor GM trees for their impacts on ecosystems. 

Furthermore, Mexico currently has no policy against planting GM 

trees.1 If transgenic trees are planted in Mexico, wind can easily 

transport pollen into the United States. Public agencies should, 

therefore, assess risks and impacts for GM trees to provide credible 

information to direct policy decisions.

Genetically modified organisms may more readily gain public 

approval in certain situations. Many exotic pests have been 

introduced into the United States, and the rate of introductions is 

increasing (National Biological Information Infrastructure 2003). 

Genetic transformation/modification of forest trees to rapidly 

introduce sources of resistance to exotic pests may be the only 

efficient way to respond to new introductions quickly enough to 

prevent ecological disasters. The long generation time of most 

forest trees complicates response to newly introduced exotic pests 

with traditional breeding methods. For example, it may be possible 

to introduce genes for resistance to the balsam wooly adelgid 

(BWA) [Adelges piceae (Ratzeburg)] into Fraser fir [Abies fraseri

(Pursh) Poir.] from other true firs (Abies spp.). BWA has been 

decimating adult Fraser fir populations in the Southern Appalachian 

Mountains since the early 1950s, and there is no known resistance 

to BWA in Fraser fir populations. However, some related species 

of Abies are apparently more resistant than Fraser fir (Mitchell and 

others 1970). Genetic transformation/modification of American 

chestnut [Castanea dentata (Marsh.)] with heterologous genes from 

1 Personal Communication. 1993. Dr. Francisco Garcia Garcia, Director of Research and 

Development, National Forest Agency, Mexico.
19

General Technical Report SRS-GTR-96

other Castanea spp. may also offer a faster means than traditional 

backcross breeding of deploying trees resistant to the chestnut 

blight (Cryphonectria parasitica) (Kubisiak and others 1997).

Genetic transformation/modification is the standard for 

demonstrating gene function. The clearest way to demonstrate gene 

function is to remove it from its background, intentionally modify its 

expression, and create transgenic lines in which to study the altered 

expression. The altered expressions can inactivate a gene (“loss of 

function” or “knockout” mutations), activate a gene when or where 

it is not expected to be expressed (“gain-of-function” mutations), or 

alter its expression so it is overexpressed or underexpressed. Thus, 

the ability to transform plants for genomics research is critical.

Research Status and Opportunities for 

the Southern Research Station

Each area of biotechnology research has potential value to our 

public- and private-sector clients, and we recommend the future 

involvement of the SRS in each area. This discussion assumes 

that the SRS through the Southern Institute of Forest Genetics 

(SIFG) wants to continue or assume a significant leadership role 

in a particular research area or to occupy a particular niche such 

as conducting research in a unique area or working on species not 

under significant study by others. However, collaborations that bring 

unique talents or resources to the same researchable question will 

greatly facilitate the proposed research.

The SIFG has a strong capability in marker applications. In the 

early 1990s, the SIFG developed the capability to employ molecular 

markers in research. It used markers effectively to study the host:

pathogen system of the southern pines and fusiform rust (Nance 

and others 1992; Nelson and others 1993; Stelzer and others 1997, 

1999). The SIFG leads the study of the genetics of the fusiform rust 

fungus (Doudrick and others 1993a, 1993b; Hamelin and others 

1994; Kubisiak and others 2004). Molecular markers can diagnose 

dangerous exotic diseases (Blomquist and Kubisiak 2003) and may 

be used to study diseases of less economic importance (Nelson 
20

Biotechnology in the Southern Research Station: A Problem Analysis 

and others 2003b). In the South, research on fusiform rust disease 

is the forest industry’s primary interest. Molecular markers have 

supported programs on loblolly and slash pines (Kubisiak and 

others 2000, Nelson and Echt 2003, Nelson and others 2003a), as 

well as a variety of less important forest species (Nelson, in press; 

Troggio and others 2001; Weng and others 2002) and other crops 

(Hawkins and others 2001; Huang and others 2000, 2002, 2003). 

The SIFG will continue to study the genetics of the southern 

pine:fusiform rust pathosystem (Nance and others 1992; Nelson 

and others 1993; Stelzer and others 1997, 1999). Molecular 

markers will be an important tool in that effort. Future plans 

include using markers to (1) facilitate studies on the stability 

and predictability of fusiform rust resistance when deployed 

operationally, (2) compare differential responses of infected and 

noninfected seedlings using microarray technology, and (3) map 

avirulence genes in the fusiform rust pathogen. 

SIFG scientists also use molecular markers to study the 

populations of threatened and endangered species (Auckland 

and others 2001, Gordon and Kubisiak 1998, Weekley and others 

2002); they are currently studying the endangered pondberry 

[Lindera melissifolia (Walt.) Blume]. Also, in collaboration with The 

American Chestnut Foundation, the SIFG uses molecular genetic 

markers to aid in the restoration of American chestnut (Huang and 

others 1998; Kubisiak 1996, 1999; Kubisiak and Roberds 2003). 

Molecular markers continue to provide data on threatened and 

endangered species so policymakers and managers can decide 

how best to conserve populations at risk. The number of species at 

risk is expected to increase, and the NFS will continue to harbor a 

significant number. Increasingly, forest managers will need timely 

information to make decisions based on sound science.

Recognizing the importance of molecular genetic markers 

in forest research, the SIFG has recently invested in new highthroughput marker technology to enable the rapid production of 

data from very large studies. The Loblolly Pine Founder Project 
21

General Technical Report SRS-GTR-96

aims to provide a baseline for genetic variation in the population of 

loblolly pine that will enable monitoring changes in that population 

through successive cycles of genetic improvement (Williams and 

others, in press). When available, these data will be a valuable 

public resource for a variety of studies, including population 

genetics, phylogeny, and paleobotany. They will also provide 

a database that has the potential for identifying and mapping 

markers associated with quantitative trait loci that code for traits of 

commercial interest. Molecular markers offer an unambiguous way 

to diagnose certain diseases such as sudden oak death, caused by 

Phytophthora ramorum (Blomquist and Kubisiak 2003), and to track 

the spread of introduced pests. Applications for molecular markers 

in protecting forest health are likely to increase as the numbers of 

exotic pests increase (National Biological Information Infrastructure 

2003). 

The sequence data from the International Populus Genome 

Consortium will soon be available to the scientific community 

(Plomion and others 2003). This effort has spawned several 

functional genomics projects in Canada, France, Sweden, and 

the United States. These large research projects are searching 

for candidate genes that code for growth and development, wood 

properties, and defense responses. The SIFG should position itself 

to take advantage of the wealth of information forthcoming from 

these model species programs. 

In summary, uses for molecular marker applications in a wide 

variety of research projects will continue and will likely increase in 

the future. The high-throughput capability of the SIFG marker lab 

provides the means to provide data quickly for both public- and 

private-sector clients. The SIFG should continue to maintain and 

enhance a strong capability in molecular markers by frequent 

upgrades of essential equipment and employing and training skilled 

technical staff.

The SIFG is revitalizing research in structural genomics. In 

the early 1990s, the SIFG initiated a significant effort in genomics 
22

Biotechnology in the Southern Research Station: A Problem Analysis 

research and produced the first molecular map (Nelson and others 

1993) and karyotype (Doudrick and others 1995) for slash pine. 

This research entered a hiatus that ended in 2001. The renewed 

effort has produced the first FISH-based karyotype of loblolly pine 

and introduced improvements in the existing slash pine karyotype 

(Islam-Faridi and others 2003). These karyotypes are fundamental 

to genomics studies that will explain genome organization, permit 

molecular mapping of regions that have little recombination, 

and encourage comparative genomics studies among species. 

Future work will generate the first FISH-based karyotypes for 

longleaf (P. palustris Mill.) and shortleaf (P. echinata Mill.) and 

enable comparative genomics studies among the southern pines. 

Exploratory work will study the feasibility of employing FISH 

with BAC clones (BAC-FISH) for physical mapping and genome 

analysis. BACs are DNA fragments 100 to 300 kb in size that 

can increase the accuracy and efficiency of physical mapping. 

Combining BAC and FISH provides a technique for rapidly 

determining the chromosome location for a group of genomic 

clones and greatly simplifies map-based cloning (Islam-Faridi and 

others 2002). These techniques may prove to be invaluable in 

studying the very large genomes of conifers.

The use of FISH technology holds great promise for advancing 

our knowledge of genome organization in the southern pines and 

other forest trees. The SIFG will fill this unique niche in the forest 

genetics community.

The SIFG must develop greater capability in bioinformatics to 

use the sophisticated new computational biology tools effectively 

and to access genomic and sequence data from other better 

characterized organisms. These goals will require additional funding 

for new equipment and technical staff.

The SIFG should collaborate to assess risks from deploying clones 

and/or GM trees. This effort will require coordinating the resources of 

several research work units to examine the genecological risks, the 

sociological implications, and a cost-benefit analysis. 
23

General Technical Report SRS-GTR-96

Summary of Recommendations

The SRS should continue to emphasize the application of 

molecular marker technology to a broad range of biological and 

ecological questions. 

The SRS should expand genomics research to include 

microarray analyses of gene expression, particularly for traits that 

affect forest health, to explore the application of FISH technologies 

to physical mapping, and to add bioinformatics capabilities. 

The SRS should deemphasize research in vegetative 

propagation and gene transformation methods, but should seek 

opportunities to support the research of others.

The SRS should evaluate the risks of deploying clones and/or 

GM trees.

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Glossary2

allele: alternative form of a genetic locus; a single allele for each locus is 

inherited from each parent.

amplification: an increase in the number of copies of a specific DNA fragment.

bacterial artificial chromosome (BAC): a vector used to clone DNA fragments 

(100- to 300-kb insert size; average, 150 kb) in Escherichia coli cell. 

bioinformatics: the science of managing and analyzing biological data using 

computing techniques (especially important in analyzing genomic research 

data).

candidate gene: a gene located in a chromosome region suspected of coding 

for a trait of interest.

centimorgan (cM): a unit of measure of recombination frequency. One 

centimorgan is equal to a 1-percent chance that a crossover will occur 

between two genetic loci in a single generation.

cDNA library: a collection of DNA sequences that code for genes that generated 

from mRNA sequences.

clone: an exact copy made of biological material such as a DNA segment, a 

whole cell, or a complete organism.

comparative genomics: the study of genetics by comparisons between 

organisms.

complementary DNA (cDNA): DNA that is synthesized from a messenger RNA

template.

contig: group of cloned (copied) pieces of DNA representing overlapping regions 

of a particular chromosome.

crossing over: the exchange during meiosis of corresponding sections of DNA, 

resulting in an exchange of alleles between chromosomes.

DNA (deoxyribonucleic acid): the molecule that encodes genetic information. 

DNA is a double-stranded molecule held together by weak bonds between 

base pairs of nucleotides. The four nucleotides in DNA contain the bases 

adenine (A), guanine (G), cytosine (C), and thymine (T). In nature, base pairs 

2

 Many definitions were taken verbatim from the following Web site and altered for context 

where necessary (http://www.ornl.gov/TechResources/Human_Genome/glossary/glossary.

html#genemapping), the Human Genome Project [Date accessed: September 16, 2003].
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form only between A and T and between G and C; thus the base sequence 

of each single strand can be deduced from that of its partner.

expressed sequence tag (EST): a short strand of DNA that is a part of a cDNA

molecule and can act as identifier of a gene.

fingerprinting: in genetics, the identification of multiple specific alleles in a 

genotype’s DNA to produce a unique identifier for that genotype.

fluorescence in situ hybridization (FISH): a physical mapping approach that 

uses fluorescent tags to detect hybridization of probes with metaphase 

chromosomes and with the less-condensed somatic interphase chromatin.

functional genomics: the study of genes, their resulting proteins, and the role 

played by the proteins in a biochemical process.

gene: the fundamental physical and functional unit of heredity. A gene is an 

ordered sequence of nucleotides on a chromosome that encodes a specific 

functional product such as a protein or RNA molecule.

gene expression: the process by which a gene’s coded information is converted 

into the structures present and operating in the cell.

gene mapping: determination of the relative positions of genes on a DNA

molecule and of the distance, in linkage units or physical units, between 

them.

gene regulation: the process by which gene expression is controlled, i.e., turned 

on and off by the cell.

genetic marker: a gene or other identifiable portion of DNA whose inheritance 

can be followed.

genome: all the genetic material in the chromosomes of a particular organism.

genomic library: a collection of clones made from a set of randomly generated 

overlapping DNA fragments that represent the entire genome of an organism.

genomics: the study of genes and their function.

homologous chromosome: chromosome containing the same linear gene 

sequences as another.

hybridization: the process of joining two complementary strands of DNA or one 

each of DNA and RNA to form a double-stranded molecule.
34

Biotechnology in the Southern Research Station: A Problem Analysis 

karyotype: a representation of an individual’s chromosomes arranged in a 

standard format showing the number, size, and shape of each chromosome 

type.

linkage: the proximity of two or more alleles on a chromosome.

linkage map: a map of the relative positions of genetic loci on a chromosome, 

determined on the basis of how often the loci are inherited together. Distance 

is measured in centimorgans (cM).

meiosis: the process of two consecutive cell divisions in the diploid progenitors 

of sex cells resulting in four daughter cells, each with a haploid set of 

chromosomes.

messenger RNA (mRNA): RNA that serves as a template for protein synthesis.

microarray: sets of miniaturized chemical reaction areas that may also be used 

to test DNA fragments, antibodies, or proteins.

mitosis: the process of nuclear division in cells that produces daughter cells 

genetically identical to each other and to the parent cell.

molecular genetics: the study of macromolecules important in biological 

inheritance.

nucleotide: a subunit of DNA or RNA consisting of a nitrogenous base (adenine, 

guanine, thymine, or cytosine in DNA; adenine, guanine, uracil, or cytosine 

in RNA), a phosphate molecule, and a sugar molecule (deoxyribose in DNA

and ribose in RNA). Thousands of nucleotides are linked to form a DNA or 

RNA molecule.

oligonucleotide: a molecule usually composed of 40 or fewer nucleotides; used 

as a DNA synthesis primer.

physical map: a map of the locations of identifiable landmarks on DNA such as 

restriction enzyme cutting sites, or genes. Distance is measured in base pairs.

 polymerase chain reaction (PCR): a method for amplifying a DNA base 

sequence using a heat-stable polymerase and two 20-base primers, one 

complementary to the (+) strand at one end of the sequence to be amplified 

and one complementary to the (-) strand at the other end. Because the newly 

synthesized DNA strands can subsequently serve as additional templates for 

the same primer sequences, successive rounds of primer annealing, strand 

elongation, and dissociation produce rapid and highly specific amplification of 

the desired sequence. PCR also can be used to detect the existence of the 

defined sequence in a DNA sample.
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General Technical Report SRS-GTR-96

polymorphism: difference in DNA sequence among individuals that may 

underlie differences among phenotypes.

population genetics: the study of variation in genes and their frequencies 

among a group of individuals.

primer: short preexisting polynucleotide chain to which new 

deoxyribonucleotides can be added by DNA polymerase.

probe: single-stranded DNA or RNA molecules of specific base sequence, 

labeled either radioactively or immunologically, that are used to detect the 

complementary base sequence by hybridization.

repetitive DNA: sequences of varying lengths that occur in multiple copies in the 

genome.

RNA (ribonucleic acid): a chemical found in the nucleus and cytoplasm of cells 

that plays an important role in protein synthesis and other chemical activities 

of the cell. 

segregation: the normal biological process whereby the two pieces of a 

chromosome pair are separated during meiosis and randomly distributed to 

the germ cells.

sequencing: determination of the order of nucleotides (base sequences) in a 

DNA or RNA molecule or the order of amino acids in a protein.

transcription: the synthesis of an RNA copy from a sequence of DNA (a gene); 

the first step in gene expression. 

transformation: a process by which the genetic material carried by an individual 

cell is altered by incorporation of exogenous DNA into its genome.

transgenic: an experimentally produced organism in which DNA has been 

artificially introduced and incorporated into the organism’s germ line.
Biotechnology in the Southern Research Station: A Problem Analysis 

Bridgwater, F.E.; Nelson, C.D. 2006. Biotechnology in the Southern Research Station: a 

problem analysis. Gen. Tech. Rep. SRS–96. Asheville, NC: U.S. Department of Agriculture, 

Forest Service, Southern Research Station. 35 p.

We provide an analysis of opportunities and challenges for biotechnology in forest research in 

the southern United States. Four major areas of biotechnology were identified and described 

and then rated for priority among three groups of researchers—private sector, public sector, and 

the USDA Forest Service, Southern Research Station (SRS). The four areas of biotechnology 

were vegetative propagation, genetic transformation/modification, genomics/bioinformatics, and 

molecular marker applications. We concluded that these three groups have different research 

priorities with respect to biotechnology and that these differences complement each other. In 

particular, the SRS should continue its work in molecular marker technology development for 

applications in tree improvement, conservation genetics, forest health, and basic science. Also, 

the SRS should increase its efforts in genomics/bioinformatics while decreasing its research 

on vegetative propagation. Finally, the SRS should work on assessing the potential risks and 

impacts of planting and managing clones and/or genetically modified trees.

Keywords: Bioinformatics, clonal forestry, forest biotechnology research, genetic 

transformation/modification, genomics, marker-assisted selection (MAs), molecular markers, 

vegetative propagation.
General Technical Report SRS-GTR-96

The Forest Service, United States Department of 

Agriculture (USDA), is dedicated to the principle 

of multiple use management of the Nation’s forest 

resources for sustained yields of wood, water, forage, wildlife, 

and recreation. Through forestry research, cooperation with 

the States and private forest owners, and management of 

the National Forests and National Grasslands, it strives—as 

directed by Congress—to provide increasingly greater service 

to a growing Nation.

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discrimination in all its programs and activities on the basis 

of race, color, national origin, age, disability, and where 

applicable, sex, marital status, familial status, parental status, 

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derived from any public assistance program. (Not all prohibited 

bases apply to all programs.) Persons with disabilities who 

require alternative means for communication of program 

information (Braille, large print, audiotape, etc.) should contact 

USDA’s TARGET Center at (202) 720-2600 (voice and TDD).

To file a complaint of discrimination, write to USDA, Director, 

Office of Civil Rights, 1400 Independence Avenue, SW, 

Washington, D.C. 20250-9410, or call (800) 795-3272 (voice) 

or (202) 720-6382 ( TDD). USDA is an equal opportunity 

provider and employer.