OFD 2000 Project Summaries

Woody Crops Research

Table of Contents

Limitations on Short Rotation Woody Crop Growth in the Southeast United States

Research Funded by: U.S. Department of Energy (DOE), Office of Fuels Development through Oak Ridge National Laboratory
Project Manager: Lynn Wright, 865-574-7378, wrightll@ornl.gov
Performing Organization: Oak Ridge National Laboratory, Oak Ridge, TN 37831
Principal Investigator(s): Gerald A. Tuskan, 865-576-8141, tuskanga@ornl.gov
Contract Number: Internal project
Contract Period: 10/99 – 9/00
Contract Funding: FY 2000: $140,000

Objective: The technical objectives are to determine if: (1) differential intra- or interspecific productivity of above ground biomass is limited by inherent photosynthetic and/or respiration rates for a given genotype, (2) water availability and nitrogen nutrition modify the role that respiration has in limiting productivity by altering the concentration of effectors of dark respiration and by altering which factor is limiting, and (3) preferential allocation of dry matter to branch and stem production may inhibit the performance of some genotypes in warmer environments.

Approach/Background: The purpose of this Cooperative Research and Development Agreement (CRADA) between ORNL and International Paper Co. is to determine productivity rates and carbon budgets for irrigated and fertilized hardwoods grown in the southeast. Recent Environmental Protection Agency (EPA) restrictions placed upon wetland ecosystems limit access to traditional supplies of hardwood fiber; demands for fiber from the southeast are increasing. For plantation-grown hardwoods to be economically viable, however, there is a need to achieve high yields across a wide range of sites where soil fertility, water availability, and climate often limit forest productivity. Such limitations must be understood and management options evaluated prior to implementing hardwood plantations in the Southeast region of the United States.

A quantitative analysis of (1) carbon fixation in foliage, (2) respiratory losses from foliage, stems, and root tissues, and (3) allocation of the remaining stored carbohydrates to the production of structural stem and branch tissues within the context of short-rotation, intensive culture biomass productivity has never been conducted. Through this CRADA, the Parties will quantify the morphological, physiological, and biochemical impacts of irrigation scheduling and nitrogen application on the growth of cottonwood, sycamore, and sweetgum. The study site and experimental design provide a unique opportunity to differentiate the quantitative contribution of a plant's photosynthetic versus respiratory processes to the overall net production of aboveground biomass under various levels of water and nitrogen availability.

Status/Accomplishments: Hardwood dry weight yield continue to remain level through the 5th growing season. The best clone in the best treatment for Populus will reach a final yield of ca. 6 dry tons per acre per year on an 8-year rotation. Sycamore produced the second highest yield at age 5, though sweetgum may exceed either Populus or sycamore over a longer rotation (est. 15 years). Osmotic potential varied among species with Populus having greater dehydration tolerance followed by sweetgum and then sycamore. Nitrogen fertilizer appears to lower dehydration tolerance in all species. Instantaneous measures of photosynthetic capacity follow the biomass-related species trend. Net respiration represents a loss of fixed carbon and shows an inverse relationship with tree size. This supports higher biomass accumulation in Populus. Physiological measures were not robust indicators of stand level productivity. Water and fertilization did not overcome the limits previously reported on SRWC hardwood production in the southeastern U.S. and respiration, even under higher night time temperatures do not account for differences in region growth rates of SRWC plantations. Anonymous genetic selection of superior genotypes appears to be the most promising means of increasing final yields in all three species.

Project Location(s): Oak Ridge, TN, Sumter, SC

Publications and Presentations:

  1. A CRADA sensitive presentation of the 5th year results was made to our CRADA partners.

Summary Date: July 2001

Limits of Drought Tolerance in Populus

Research Funded by: U.S. Department of Energy (DOE), Office of Fuels Development through Oak Ridge National Laboratory
Project Manager: Gerald A. Tuskan, 865-576-8141, tuskanga@ornl.gov
Performing Organization: Oak Ridge National Laboratory, Environmental Sciences Division, P.O. Box 2008, Oak Ridge, TN 37831-6422
Principal Investigator(s): T. J. Tschaplinski, 865-574-4597, tschaplinstj@ornl.gov
Contract Number: Internal project
Contract Period: 4/97 - 09/00
Contract Funding: FY 2000: $25,000

Objectives: The long-term goal of this research is to support the development of biomass production systems for energy conversion by providing a more fundamental understanding of drought tolerance mechanisms that can be exploited to achieve high productivity on potentially stressful sites. The primary objectives of the research are to determine 1) the extent of drought tolerance of poplar in currently available germplasm, 2) QTL for drought tolerance, analyzed by using structured multiple-generation pedigrees, and 3) the extent that drought tolerance can be increased through selective breeding.

Approach/Background: A completed Cooperative Research and Development Agreement (CRADA) between Oak Ridge National Lab (ORNL) and Boise Cascade Corp. (BCC) provided a validation of the role that low osmotic potential and osmotic adjustment have in determining drought tolerance of poplar clones in the field. Follow-on collaborative research in the Pacific Northwest between ORNL, BCC, and University of Washington (UW) is focusing on the advanced-generation poplar pedigrees and clones from diverse crosses generated by UW and established and managed by BCC at Ice Harbor Fiber Farms, near Pasco, WA. Pure clones and hybrids of P. trichocarpa (T), P. deltoides (D), and P. nigra (N) are being studied. The research is determining osmotic potential at full turgor (Ypo) and identifying the most promising of the drought tolerant, high productivity F1 clones for selective breeding to enhance tolerance. Simultaneous analysis of clones from a structured outbred pedigree for Ypo and solutes that constitute Ypo will permit marker identification.

Status/Accomplishments: Effort in the final year of the project was directed towards the preparation of ORNL/TM-2000/6 titled “Role of osmotic adjustment in plant productivity” authored by G.M. Gebre and T.J. Tschaplinski.

Publications and Presentations:

  1. Gebre, G.M., and T. J. Tschaplinski. 2000. Role of osmotic adjustment in plant productivity. ORNL/TM-2000/6. Oak Ridge National Laboratory, Oak Ridge, Tennessee.

Summary Date: July 2001

Minnesota Hybrid Poplar Research Cooperative

Research Funded by: U.S. Department of Energy (DOE), Office of Fuels Development through Oak Ridge National Laboratory
Project Manager: Gerald A. Tuskan, 865-576-8141, tuskanga@ornl.gov
Performing Organization: Agricultural Utilization Research Institute, PO Box 599, Crookston, MN 56716, http://www.auri.org
Principal Investigator(s): Edward Wene, 218-281-9014, ewene@auri.org
Contract Number: 4000005906
Contract Period: November 1, 2000-October 31, 2005
Contract Funding: FY 2000: $14,000

Objective: The goal of the Minnesota Hybrid Poplar Research Cooperative (MHPRC) is to improve genetics and management of hybrid poplar to increase yield and product value to growers and end-users. MHPRC research is done in cooperation with member companies that provide land for establishment of experiments on multiple sites throughout the state. The MHPRC research program dovetails with other BFDP-sponsored projects in the region through sharing of genetic material and information.

Approach/Background: The MHPRC program encompasses breeding and field-testing of progeny, clone testing, nutrition of plantations and diagnostics, growth and yield evaluation, vegetation management as well as technical assistance to the public. Through the 2000 growing season, the MHPRC has established twenty-seven research sites which include experiments involving progeny tests, clone trials, herbicide tests and nutrition studies. Growth data from all sites are collected annually.

Status/Accomplishments: The MHPRC has had a successful history of Populus breeding since 1996. To date, we have produced a total of 316 families comprised of 88 DxD, 70 DxM, 64 DxN, 57 (DM)xD backcrosses, 8 F2 and 29 miscellaneous families (DXT F1 and others). The total number of genotypes in the “pipeline” slated for field-testing is approximately 22,000. Year 2000/01 breeding involved 150 breeding attempts with emphasis on production of interspecific crosses of selected P. deltoides native to the northcentral region with P. maximowiczii, P. nigra and to a limited extent, P. trichocarpa. As has been the case in previous years, we expect that approximately 50% of these crosses will produce families comprised of at least 60 viable seedlings each. In addition to F1 crosses, fast-growing, Septoria-susceptible clones of DXM parentage selected from clone tests in Minnesota were backcrossed to superior native-P. deltoides to decrease Septoria-susceptibility and maintain or enhance growth rate. Depending on the year the families were bred, progeny is in various stages of propagation for field-testing or have already been planted in field tests at multiple sites throughout Minnesota. Two such progeny tests were planted in June of 2001 near Bertha, MN (central MN) and Baudette, MN (northern MN). These tests contain 36 families with 30 genotypes/family in a replicated clone-within-site design and an additional 35 families planted as family-level trials with no clonal replication within site. Based on our experience, the decision to replicate only the upper 50th percentile of genotypes is solely a function of growth rate in nurseries and the practical feasibility of producing high-quality ramet copies of each clone in sufficient numbers for replication. We produce clone-within-site replicates of the upper 50th percentile of families for field tests and test the remaining genotypes in family-level tests.

Concurrent with MHPRC breeding has been establishment of clone tests of genotypes that were bred prior to formation of the MHPRC but not extensively field-tested. The oldest set of these plantings is now four years of age and we are beginning to make selections among DxM and pure native P. deltoides clones based on growth rate and disease resistance. Results of clone tests demonstrate the potential to achieve significant yield gains through genetic selection. After four years, means of the ten fastest-growing clones compared to the mean of commercial controls (clones NM6 and DN34) embedded in these tests range from a ratio of 1.5 to over 3.0 times depending on site. The average ratio of the mean volume-index of the ten fastest-growing genotypes in clone tests compared to that of commercial controls in 1997-planted tests is 1.8. For this reason, we expect that yields of poplar plantations will increase significantly in the near future. In most cases, the upper tier of clones is comprised of roughly a 50/50 split between pure-P. deltoides and P. deltoides X maximowiczii. As soon as is practically feasible, flowers from the upper tier of clones are being used in F1 and backcrossing in the MHPRC breeding program to produce offspring of the most promising genotypes. Superior clones identified to date are being propagated for planting in replicated yield blocks to determine yield potential under what we consider an optimal genetics and nutrition management regime.

The MHPRC continues to conduct research on nutrition of plantations on a range of sites throughout the state. Results to date demonstrate statistically and practically significant growth responses to fertilization with annual increments being increased by twenty five to seventy percent through moderate fertilization depending on site. Relationships between Minolta SPAD meter readings and foliar nitrogen content were found to be statistically significant (p<0.01) with the R-squared of the regression lines being 0.60 and 0.78 for NM6 and DN-clones, respectively.

Herbicide studies in 2000 continued work on Milestone timing, rates, and combinations with Scepter and others. At Rhinelander, hybrid poplar phytotoxicity studies compared fall preplant applications with spring postplant applications. Results indicate that NM6 is Milestone rate sensitive, Oust sensitive, Scepter tolerant, I4551 is Milestone tolerant, Oust tolerant, Scepter sensitive, DN2 is Milestone tolerant and DN34 is Milestone, Oust, Scepter tolerant. A study on International Paper lands near Bertha, MN compared hybrid poplar growth of spring-applied herbicides to the same treatments oversprayed midseason with Milestone. Measurements continued on plots that had been treated in fall of 1999 with several herbicide treatments on Potlatch Farm 3 and a new grass herbicide study was installed on the same site in June. In general, Scepter alone and in combination provided consistent weed control while Milestone alone at different rates was near the bottom in tree height rankings. The earliest label approval for Milestone is likely to be in 2002 and Assure II now has a 24C label for Minnesota.

Since 1995, the MHPRC has established and measured replicated yield blocks of new clones on several sites throughout Minnesota. These clones include DN2, DN5, DN9, DN17, DN34, DN55, DN70, DN182 and NM6. Based on these tests, only DN2, DN5 and NM6 are recommended for further commercial planting in Minnesota.

Project Location(s): Polk, Red Lake, Pennington, Norman, Marshall, Roseau, Douglas, Todd, St. Louis counties in Minnesota.

Summary Date: July 2001

Physiology of Poplar Disease Resistance

Research Funded by: U.S. Department of Energy (DOE), Office of Fuels Development through Oak Ridge National Laboratory
Project Manager: Gerald A. Tuskan, 865-576-8141, tuskanga@ornl.gov
Performing Organization: Washington State University, 7612 Pioneer Way E., Puyallup, WA 98371, www.puyallup.wsu.edu/poplar
Principal Investigator(s): Jon D. Johnson, 253-445-4522, poplar@wsu.edu
Contract Number: 6500000596
Contract Period: 8/99-8/04
Contract Funding: FY 2000: $12,500

Objective: The genetic improvement of the native black cottonwood (Populus trichocarpa) and elucidation of components of productivity in this species have been the primary goals of a nearly three decade long cooperative program between Washington State University and the University of Washington. Introduction of fast growing hybrid poplar clones developed for the Pacific Northwest into other regions of the US, including the mid-west and southeast, would allow for significant production of biomass for energy as well as help counter global warming through carbon dioxide sequestration. Before introducing hybrid poplar into other regions of the US, it will be necessary to control diseases that would otherwise limit the growth potential of these trees. Breeding for disease resistance is the main strategy for developing resistant hybrids that will thrive elsewhere. However, an understanding of host resistance/tolerance mechanisms, and host-pathogen interactions are required before breeding efforts can be successful. The two of the most important diseases that limit poplar productivity in the US are leaf rust, caused by Melampsora spp. and stem canker, caused by Septoria musiva. Melampsora can kill young trees and reduce the growth of older trees by 30 to 40 %. Septoria canker is prevalent in the mid-west, aggressively attacking and killing our hybrid poplars while having little economic impact on the native eastern cottonwood (P. deltoides). Durability of disease resistance is a critical issue since the hybrids are grown over large areas and for rotations of from six to twenty or more years. It is, therefore, imperative that we begin to understand the mechanisms of how the host tree and pathogen interact, so we can breed for stable resistance in the hybrid poplars and use proper cultural treatments to minimize disease incidence and/or impact. Stable resistance to these pathogens will ultimately result in higher yields due to the higher productivity of the WSU/UW hybrids and to lower production losses resulting from disease. This, coupled with increasing land area put into SRIC plantations, will substantially increase biofuel feedstock production in the US.

Approach/Background: In the area of tree breeding and molecular genetics, our objective is to create hybrids with traits for furthering disease resistance research. New hybrids are being produced by traditional breeding procedures and then tested for disease resistance. As resistant hybrids are identified, they are being used in studies that will identify mechanisms of resistance as well as inheritance in offspring. Furthermore, to develop disease resistant hybrids, pollen from new species, especially from China, is being used in controlled crosses.

In the area of growth and physiological impacts of disease, our objective is to understand physiological changes that occur during the infection process and symptom manifestation and to begin to identify quantifiable traits related to host physiology. To better understand the physiology of disease resistance, a combination of controlled environment, greenhouse and field studies have been initiated. Using known resistant and susceptible hybrids and poplar species along with different species and races of leaf rust, we are beginning to understand early responses to rust infection.

Status/Accomplishments:

Tree Breeding and Molecular Genetics. As part of this collaborative breeding effort, we received pollen representing P. deltoides from WESTVACO, OP367 from University of Washington, and P. tomentosa, P. szechuanica and P. tomentosa x P. bolleana from China. We collected female branches from 4 P. trichocarpa female trees (3 of which have been bred previously, 1 is a new mother tree from Silverdale, WA) and received some branches of NM-6 from T. Bradshaw. A total of 27 crosses were made during April and seeds collected starting in mid-May. We also conducted embryo rescue on a portion of closed capsules as when the capsules began opening. Of these 27 crosses, 14 produced over 1300 seedlings. A majority of the progeny was planted at Farm 5 in August 2000 and they were rated for rust susceptibility in September. The remaining progeny was too small to outplant and were grown in the greenhouse over the winter and planted this spring. The better growing hybrids will be put into trials to test for growth and disease resistance. Some of the faster growing hybrids with the Chinese species will be field tested in the mid-west for resistance to Septoria. Additional hybrids will be bred next spring to continue the work on this subtask.

Growth and Physiological Impacts of Disease. Early studies were unsuccessful due to the poor quality of the rust spores provided. As rust infections started in the summer of 2000 at Farms 1 and 5, and in Ft. James’ plantations, spores were collected and stored. The three rust races have been tested against a wide range of clones and known differentials have been documented for future studies. Using uredial spore morphology, we have been to able to determine that the Farm 1 rust is M. medusae, the Farm 5 rust is M. occidentalis, and the Ft. James rust is a putative hybrid. Through collaboration, we have an additional race collected from 15-29. This may be a unique race since it has just appeared in the summer of 2000 on a historically resistant clone. Of particular interest is that the rust was present in two out three plantations with rust incidence increasing with the number of irrigations; the non-irrigated plantation showed no rust incidence. A field study is being planned to follow the possible link between summer irrigation and rust infection next summer. Attempts to identify the species of this rust from spores on field-collected leaves were not successful due to the poor quality of the leaves and the spores. The rust is now in culture on leaves of 15-29 and after a couple cycles we will have enough uredial spores to try again.

A Ph.D. student, Jaime Banaag, was recruited and began microscopy work including SEM at the University of Washington. His project entails following early infection processes as it relates to virulent and avirulent rust races. Two greenhouse studies were completed to determine proper rates of salicylic acid to induce planned cell death (PCD) and to determine the effect of tree growth rate on rust infection and to quantify growth rate changes due to leaf loss. Two clones were grown in solution culture at 2 and 6% relative nitrogen addition rates. When the trees reached the 8-10 leaf developmental stage, the fifth leaf on half of the trees were inoculated with a race of rust putatively virulent on one of the clones and avirulent on the other. Both clones developed significant amounts of uredia. The trees were sampled intensively for gas exchange, leaf area development and nitrogen partitioning. Relative growth rates will be determined to compare inoculated and control trees over the 3-month study period. The data are in the process of being analyzed. 9

Project Location(s): Puyallup, WA, Pend Oreille and Stevens Counties, WA, Boardman, OR, Salem, OR

Publications and Presentations:

  1. Johnson, J.D. 2000. Hybrid Poplar: An Overview. Pp. 15-20. In Hybrid Poplars in the Pacific Northwest: Culture, Commerce and Capability, Keith A. Blatner, Jon D. Johnson and David M. Baumgartner, eds. WSU Cop. Exten. bulletin MISC0272, 114 p.
  2. Johnson, J.D. 2000. Nutrient Use and Stand Sustainability. Pp. 101-104. In Hybrid Poplars in the Pacific Northwest: Culture, Commerce and Capability, Keith A. Blatner, Jon D. Johnson and David M. Baumgartner, eds. WSU Cop. Exten. bulletin MISC0272, 114 p.
  3. Moore, B, J. Bassman and J.D. Johnson. 2000. Hybrid Poplars as Riparian Buffers. Pp. 59-64. In Hybrid Poplars in the Pacific Northwest: Culture, Commerce and Capability, Keith A. Blatner, Jon D. Johnson and David M. Baumgartner, eds. WSU Cop. Exten. bulletin MISC0272, 114 p.

Summary Date: July 2001

Poplar Molecular Genetics Cooperative

Research Funded by: U.S. Department of Energy (DOE), Office of Fuels Development through Oak Ridge National Laboratory
Project Manager: Gerald A. Tuskan, 865-574-8141, tuskanga@ornl.gov
Performing Organization: University of Washington, College of Forest Resources, Box 355325, Seattle, WA 98195
Principal Investigator(s): H.D. Bradshaw, Jr., 206- 616-1796, toby@u.washington.edu
Contract Number: 4000003344
Contract Period: 10/2000 - 9/2005
Contract Funding: FY 2000: $25,000

Objective: The goals of the PMGC are to: 1) increase understanding of the molecular genetic mechanisms causing variation in productivity and quality traits in hybrid poplar; and, 2) use research results to accelerate progress in poplar breeding for biomass yield.

Approach/Background: The key to sustained genetic improvement in Populus is a detailed genetic understanding of traits such as biomass yield, wood chemistry, and disease resistance. This will accelerate progress in breeding by providing improved methods to identify superior poplar clones for immediate commercial use, parents for the next generation of hybrids, and isolated genes for biotechnological manipulation.

Several methods are being used to identify, test, and manipulate individual genes affecting biomass productivity. Candidate genes are located by a combination of map-based cloning, QTL mapping, genome collinearity with Arabidopsis, and comparative genomics. These candidates are then engineered to enhance or suppress expression in transgenic hybrid poplars, and the effects of the transgenes are studied in greenhouse experiments.

Status/Accomplishments: The PMGC has attracted member organizations from three continents, four countries, fourteen companies, four government agencies, and three universities. The annual PMGC budget leverages DOE funding more than 2-fold, despite a decline in membership due to consolidation within the forest products industry.

The PMGC has produced more than 15,000 new hybrid poplar clones for testing and deployment by member organizations; in many cases these represent the first new germplasm tested in a decade. Field trials are in place from Chile to Canada, and from Washington to Florida. Many of these clones appear to be highly promising in terms of biomass yield.

The PMGC has developed the first and most extensive collection of microsatellite markers for Populus. These markers are now in use by researchers around the world for comparing genetic maps among poplar pedigrees, determining clonal identity for quality control, paternity testing, and estimation of gene flow from plantation forests into native stands. A bacterial artificial chromosome (BAC) genomic library, suitable both for cloning genes and for the eventual construction of a physical map of the Populus genome, has been constructed and used to isolate a variety of candidate genes expected to enhance disease resistance, improve biomass yield, or modify tree architecture.

Project Location(s): Seattle, Washington.

Publications and Presentations:

  1. Frewen, B.E., Chen, T.H.H., Howe, G., Davis, J., Rohde, A., Boerjan, W., & Bradshaw, H.D., Jr. (2000) QTL and candidate gene mapping of bud set and bud flush in Populus. Genetics 154: 837-845.
  2. Bradshaw, H.D., Jr. and Strauss, S.H. (2000) Breeding strategies for the 21st Century: Domestication of poplar. Proceedings of the International Poplar Council Meeting, Portland, OR, September (in press).
  3. Bradshaw, H.D., Jr., Ceulemans, R., Davis, J., & Stettler, R.F. (2000) Emerging model systems: Poplar (Populus) as a model forest tree. Journal of Plant Growth Regulators 19(3): 306-313.
  4. Newcombe, G, Stirling, B., McDonald, S., and Bradshaw, H.D., Jr. (2000) Melampsora x columbiana, a natural hybrid of M. medusae and M. occidentalis. Mycological Research 104(3): 261-274.

Summary Date: July 2001

Tree Genetic Engineering Research Cooperative

Research Funded by: U.S. Department of Energy (DOE), Office of Fuels Development through Oak Ridge National Laboratory
Project Manager: Gerald A. Tuskan, 865-574-8141, tuskanga@ornl.gov
Performing Organization: Oregon State University, Forest Science Dept., Corvallis, OR 97331, http://www.fsl.orst.edu/tgerc/
Principal Investigator(s): Steven H. Strauss, 541-737-6578, strauss@FSL.orst.edu , Richard Meilan, 541- 737-6097, meilanr@FSL.orst.edu
Contract Number: 400004295
Contract Period: 6/00 – 9/04
Contract Funding: FY 2000: $25,000

Objective: To conduct research and transfer technology to members for use of genetically engineered trees in short-rotation culture. The TGERC program is adaptive and environmental in nature, focusing on traits valued by growers and seeking to understand and mitigate environmental risks of transgenic trees. Research projects include: engineering reproductive sterility; controlling flowering time; improving transformation efficiency; producing herbicide-, disease-, and insect-resistant transgenics; and assessing the genetic risks of transgenic poplars. These practical applications of genetic engineering can provide numerous benefits to biomass producers by: 1) enhancing tree growth, 2) facilitating use of marginal land, 3) improving product quality, 4) decreasing management costs, and 5) reducing environmental impacts.

Approach/Background: Interspecific hybridization has led to the development of very fast-growing lines of hybrid poplar. Some of these hybrid lines are now being grown in large commercial plantations throughout the U.S. and Canada. Poplars are primarily grown for pulp and biomass, but are also valuable for removal of agrochemicals from groundwater, bioremediation of polluted sites, and for stream bank stabilization and restoration, and are increasingly being grown for solid wood.

Genetic engineering will improve poplar’s utility for short-rotation intensive culture. Although hybrid poplars have tremendous growth potential, they are very susceptible to insect herbivory, vegetative competition, and a variety of pathogens. Genes are now available to ameliorate these shortcomings; introducing them into commercially important hybrid clones will greatly enhance their usefulness.

Poplar is an ideal model system for woody plant genetic manipulation because it is easily transform-able and regenerable, and has a small genome. Several poplar clones are readily transformed with Agrobacterium tumefaciens. Techniques developed by us have greatly improved the efficacy with which previously recalcitrant, but commercially important, clones can now be transformed and regenerated.

Status/Accomplishments:

  • The promoter region of the poplar PTD (homolog of AP3) floral gene gave consistent floral expression, and was used to successfully disrupt the development of floral organs, in Arabidopsis, tobacco, and poplar.
  • We identified more than 70 poplar genes, comprising 26 gene families that are homologous to genes affecting time of flowering in Arabidopsis.
  • Seven new field trials, including 4,583 trees and 111 new transgenic lines, that contain insect and/or glyphosate resistance genes, were planted in five states.
  • Three scientific articles were published in major international journals that describe the DNA sequence and expression of four floral homeotic genes from poplar.
  • A new competitive research grant from the U.S. Department of Agriculture for $539,000 will accelerate and expand TGERC research in control of flowering.
  • The STEVE (Simulation of Transgene Effects in a Variable Environment) model is essentially complete. We are now conducting sensitivity analyses on test landscapes.
  • Plans are well underway for an international meeting on molecular biology of forest trees in the Pacific Northwest, including a symposium on ecological aspects of transgenic plantations.
  • TGERC staff continues to play key roles in the global and national discussion on genetically modified (GM) trees in forestry.

Publications and Presentations:

  1. Brunner, A.M., W.H. Rottmann, L.A. Sheppard, K. Krutovskii, S.P. DiFazio, S. Leonardi, and S.H. Strauss. 2000. Structure and expression of duplicate AGAMOUS orthologs in poplar. Plant Molec. Biol. 44:619-634.
  2. Brunner, A.M, J.S. Skinner, R. Meilan, and S.H. Strauss. Genetic engineering of reproductive sterility: The promise and problems of developing methods for commercial application. International Poplar Commission meeting Vancouver, WA, September 2000.
  3. Brunner, A., S. Dye, V. Hollenbeck, J. Skinner, and S. Strauss. Poplar homologs of genes controlling floral meristem identity and flowering time: Expression over a seasonal cycle and a continuous age gradient. ASPP, July 2000.
  4. DiFazio, S.P., R. Meilan, C. Ma, S. Cheng, J.A. Eaton, G. Beauchamp, E. Hoien, B.J. Stanton, T. Agens, L.K. Miller, R.P. Crockett, R.R. James, and S.H. Strauss. Genetic engineering of hybrid poplar: High levels of Roundup and leaf-beetle resistance in genetically engineered hybrid cottonwoods. SAF National meeting, Portland, OR, September 1999.
  5. DiFazio, S.P., S. Leonardi, W.T. Adams, S.L. Garman, and S.H. Strauss. Potential impacts of hybrid poplar plantations on black cottonwood populations. International Poplar Commission meeting, Vancouver, WA, September 2000.
  6. Han, K.-H., R. Meilan, C. Ma, and S.H. Strauss. 2000. An Agrobacterium tumefaciens transformation protocol effective in a variety of cottonwood hybrids (genus Populus). Plant Cell Rep. 19:315-320.
  7. Meilan, R., K.-H. Han, C. Ma, R.R. James, J.A. Eaton, B.J. Stanton, E. Hoien, R.P. Crockett, and S.H. Strauss. 2000. Development of glyphosate-tolerant hybrid cottonwoods. TAPPI J. 83(1):164-166.
  8. Meilan, R., C. Ma, S. Cheng, J.A. Eaton, L.K. Miller, R.P. Crockett, S.P. DiFazio, and S.H. Strauss. 2000. High levels of Roundup® and leaf-beetle resistance in genetically engineered hybrid cottonwoods. In: K.A. Blatner, J.D. Johnson, and D.M. Baumgartner, eds., Hybrid Poplars in the Pacific Northwest: Culture, Commerce and Capability. Washington State University Cooperative Extension Bulletin MISC0272, Pullman, WA, pp. 29-38.
  9. Meilan, R. Field trials of transgenic hybrid cottonwood demonstrate high levels of resistance to crysomelid beetles and glyphosate herbicide. International Poplar Commission meeting, Vancouver, WA, 26 September 2000.
  10. Rottmann, W.H., R. Meilan, L.A. Sheppard, A.M. Brunner, J.S. Skinner, C. Ma, S. Cheng, L. Jouanin, G. Pilate, and S.H. Strauss. 2000. Diverse effects of overexpression of LEAFY and PTLF, a poplar (Populus) homolog of LEAFY / FLORICAULA, in transgenic poplar and Arabidopsis. Plant J. 22:235-246.
  11. Sheppard, L.A., A.M. Brunner, K.V. Krutovskii, W.H. Rottmann, J.S. Skinner, S.S. Vollmer and S.H. Strauss. 2000. A DEFICIENS homolog from the dioecious tree Populus trichocarpa is expressed in both female and male floral meristems of its two-whorled, unisexual flowers. Plant Physiology 124:627-639.
  12. Skinner, J.S., R. Meilan, A.M. Brunner, and S.H. Strauss. 2000. Options for genetic engineering of floral sterility in forest trees. In: S.M. Jain and S.C. Minocha (eds.), Molecular Biology of Woody Plants, Volume 1. Kluwer Academic Publishers, Dordrecht, The Netherlands, pp. 135-153.
  13. Skinner, J.S., R. Meilan, C. Ma, and S.H. Strauss. From gene isolation to genetic modification: Use of a poplar floral homeotic gene for engineering of reproductive sterility. International Poplar Commission meeting, Vancouver, WA, September 2000.
  14. Strauss, S.H., K. Raffa, and P. List. 2000. Ethics and transgenic plantations. J. Forestry 98(7):47-48.
  15. Strauss, S. and R. Meilan. 2000. Tree Genetic Engineering Research Cooperative. Western Forester 45(2):14.
  16. Strauss, S.H., R. Meilan, S.P. DiFazio, A.M. Brunner, J.S. Skinner, R. Mohamed, and J. Carson. 2000. Tree Genetic Engineering Research Cooperative Annual Report: 1999-2000. Forest Research Laboratory, Oregon State University. 43 pp.
  17. Strauss, S.H., S.P. DiFazio, and R. Meilan. Challenges to commercial uses of transgenic trees in forest plantations: The case of poplars. International Symposium on Biosafety of Transgenic Crops, Saskatoon, Canada, July 2000.
  18. Strauss, S.H., R. Meilan, and S.P. DiFazio. Genetically modified poplars: State of the art and perspectives on the public controversy. International Poplar Commission meeting, Vancouver, Washington, September 2000.
  19. Thompson, P.B. and S.H. Strauss. 2000. Research ethics for molecular silviculture. In: Molecular Biology of Woody Plants. S.M. Jain and S.C. Minocha (eds.), Kluwer Academic Publishers, The Netherlands, pp. 585-611.

Summary Date: July 2001