Progress 09/15/03 to 09/14/06
Outputs
A tissue culture protocol was established to develop salt tolerance in California bulrush, with the intention of increasing its usefulness in the coastal environment. Cellular selection was conducted by exposing calli to salt and eight regenerated lines appear to possess higher salt tolerance. Evaluation field trials were established at two saline and three freshwater sites. The lines are maintained in greenhouses. Genetic diversity data analysis will be used to help select the best lines for release. Conventional plant breeding will be used to enhance salt tolerance using these lines as a germplasm base. Promising California bulrush lines were selected for plant vigor and reproductive attributes including height, spread, stem density, stem diameter, and seed production. Genetic diversity of 190 Sea Oat genotypes from 19 accessions was evaluated based on 417 AFLP polymorphic loci. They exhibited a low level of genetic similarity. Florida accessions, FL-33 and FL-39,
were most genetically diverse and those from both Carolinas and Virginia (VA-53, NC-1, NC-11, and SC-15) were less variable. Cluster analysis separated the plants into four major clusters with the largest proportion of variability occurring at the state level (48%). Performance trials were conducted at Biloxi Beach, MS; Holly Beach, LA; and in cooperation with NC State University at Wrightsville Beach, NC. A total of 147 superior plants were selected from Holly Beach (71) and Biloxi (76). Rooted tillers of these were dug and transplanted to a greenhouse in Baton Rouge prior to the hurricanes of 2005. These superior genotypes will be increased for use in breeding and ecologic studies. Several projects in cooperation with federal and state agencies were completed on marsh terracing, which provides a more comprehensive understanding of the hydrologic-soil-plant responses necessary to provide scientific standards required for expensive, large-scale wetland restoration projects. A
comprehensive final report titled 'Assessment and Potential for Vegetative Remediation of Selected Brown Marsh and Disturbed Sites in the Barataria and Terrebonne Basins' was completed. Elements of the study include seed collection, storage, and germination methodologies; aerial seeding of four sites on large-scale (34 acres) plots; and monitoring of site seed distribution, germination, seedling survival, mature plant density, and productivity relative to normal Marsh. The molecular basis of salt tolerance of smooth cordgrass (Spartina alterniflora)was studied using cDNA-AFLP. Genes expressed in response to salt stress at different time points in both roots and leaves were profiled. A number of candidate cDNA fragments have been isolated, cloned, and sequenced. Preliminary data indicated that many stress responsive genes were over-expressed or many new genes were induced in response to salt stress.
Impacts
The LSU AgCenter coastal plants project plays a critical role in identifying and developing superior genotypes of native plants for use in coastal preservation and reclamation. This project also develops seed handling protocols and investigates seed physiology, plant pathogens, and other areas important to development of a coastal reclamation enterprise
Publications
- Fang, Xiaobing, P.K. Subudhi, and B.C. Venuto, and S.A. Harrison. 2004. Mode of pollination, pollen germination, and seed set in smooth cordgrass (Spartina alterniflora. Poaceae). Int. J. Plant Sci. 165:395-401.
- Xu, Han. 2006. Landscape and edaphic factors influencing volunteer colonization of reconstructed marsh in coastal Louisiana. M.S. Thesis. Louisiana State University.
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Progress 01/01/05 to 12/31/05
Outputs
Ten promising California bulrush lines were selected for plant vigor and reproductive attributes including height, rate of spread, stem density, stem diameter, and seed production based in field studies completed in 2005. Eight additional lines were selected from a salinity screening study (0 to 18 ppt). These lines together with the released cultivar 'Restorer' were subsequently increased clonally for replicated testing and release as varieties. Peformance trials were conducted at Biloxi Beach, MS; Holly Beach, LA; and in cooperation with NC State University at Wrightsville Beach, NC to select the most promising line for release. Sea oat accessions were evaluated. Based on data from the Holly Beach and Biloxi sites, 147 superior plants were selected at Holly Beach (71) and Biloxi (76). Rooted tillers of these were dug and transplanted to a greenhouse in Baton Rouge prior to the hurricanes of 2005. These superior genotypes will be planted in replicated trials in 2006
and used in breeding and ecologic studies. Scientists of the LSU AgCenter coastal plants project, working with federal and state agencies involved with the CWPPRA program completed several field trials associated with marsh terracing. The 'Establishment of Vegetative Plantings as a Restoration Measure on Marsh Terraces' project will provide a more comprehensive understanding of the hydrologic-soil-plant responses that are essential before terracing restoration can approach the scientific standards required for acceptance of expensive, large-scale wetland restoration projects. A comprehensive final report titled Assessment and Potential for Vegetative Remediation of Selected Brown Marsh and Disturbed Sites in the Barataria and Terrebonne Basins was completed. Elements of the study include seed collection, storage, and germination methodologies; development of an aerial seeding formula model; actual seeding of multi-sites (4) and large-scale (34 acres) plots; and extensive monitoring of
site seed distribution, germination, seedling survival, mature plant density, and productivity relative to normal marsh. The molecular basis of salt tolerance of smooth cordgrass (Spartina alterniflora)was studied using cDNA-AFLP. Genes expressed in response to salt stress at different time points in both roots and leaves were profiled. A number of candidate cDNA fragments have been isolated, cloned, and sequenced. Preliminary data indicated that many stress responsive genes were over-expressed or many new genes were induced in response to salt stress.
Impacts
The LSU AgCenter coastal plants project plays a critical role in identifying and developing superior genotypes of native plants for use in coastal preservation and reclamation. This project also develops seed handling protocols and investigates seed physiology, plant pathogens, and other areas important to development of a coastal reclamation enterprise
Publications
- Xu, Han. 2005. Landscape and edaphic factors influencing volunteer colonization of reconstructed marsh in coastal Louisiana. M.S. Thesis. Louisiana State University.
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Progress 01/01/04 to 12/31/04
Outputs
A tissue culture protocol was established to develop salt tolerance in California bulrush. It thrives in deep water and has value in prevention of wave erosion, but is limited due to salt sensitivity. Cellular selection was conducted by exposing calli to salt and regenerating surviving calli. 34 recovered plants are under evaluation in the greenhouse and field plots. 48 NRCS bulrush accessions were evaluated and 8 appear to possess higher salt tolerance. Agronomic evaluation is undergoing in freshwater ponds near Crowley, LA and controlled a saltwater environment near Houma, LA. Genetic diversity data will be used to help select the best lines for release. These lines will be used as parental lines to develop greater salt tolerant lines through conventional breeding methods. 190 Sea Oat genotypes from 19 accessions were evaluated for genetic diversity. A total of 417 AFLP polymorphic loci were found and the sea oat plants exhibited a low level of genetic similarity.
Florida accessions, FL-33 and FL-39, were most genetically diverse and those from both Carolinas and Virginia (VA-53, NC-1, NC-11, and SC-15) were less variable. Cluster analysis separated the plants into four major clusters with the largest proportion of variability occurring at the state level (48%). The relationship between genetic diversity and geographic source of sea oats populations may help identify plants for restoration that do not compromise adaptation and genetic diversity. These sea oat accessions have been planted at Biloxi Beach, MS; Holly Beach, LA; and in cooperation with NC State University at Wrightsville Beach, NC. Superior genotypes in these plantings will be increased and used in breeding and ecologic studies. Scientists of the LSU AgCenter coastal plants project, working with federal and state agencies involved with the CWPPRA program completed several field trials associated with marsh terracing. The "Establishment of Vegetative Plantings as a Restoration
Measure on Marsh Terraces" project will provide a more comprehensive understanding of the hydrologic-soil-plant responses that are essential before terracing restoration can approach the scientific standards required for acceptance of expensive, large-scale wetland restoration projects. The molecular basis of salt tolerance of smooth cordgrass (Spartina alterniflora)was studied using cDNA-AFLP. Genes expressed in response to salt stress at different time points in both roots and leaves were profiled. A number of candidate cDNA fragments have been isolated, cloned, and sequenced. Preliminary data indicated that many stress responsive genes were over-expressed or many new genes were induced in response to salt stress.
Impacts
The LSU AgCenter coastal plants project plays a critical role in identifying and developing superior genotypes of native plants for use in coastal preservation and reclamation. This project also develops seed handling protocols and investigates seed physiology, plant pathogens, and other areas important to development of a coastal reclamation enterprise.
Publications
- Fang, Xiaobing, P.K. Subudhi, and B.C. Venuto, and S.A. Harrison. 2004. Mode of pollination, pollen germination, and seed set in smooth cordgrass (Spartina alterniflora. Poaceae). Int. J. Plant Sci. 165:395-401.
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Progress 01/01/03 to 12/31/03
Outputs
This project is a component of an ongoing cooperative coastal plants improvement program of the LSU Agricultural Center and NRCS Plant Materials Center at Galiano, LA. The project includes evaluation of genetics and seed characteristics of smooth cordgrass, sea oats, black mangrove, and other coastal marsh species. Seed physiology studies on S. alterniflora showed the optimum temperature range for germination is 22C - 34C. Above (37C) and below (17C) these temperatures, primarily root emergence was delayed, extending the time differential between shoot and root emergence. A dramatic delay in the timing of root emergence occurred between 34C and 37C. A viability assay, to determine whether these recalcitrant seeds are dormant or dead, was developed. In contrast to previous literature reports, gibberellic acid was found to break dormancy of Spartina. A critical moisture content range between 32-35% moisture content (DWB) for viability loss was confirmed by incubating
non-dormant seeds over a series of saturated salt solutions. It was observed that seed death of Spartina by drying occurs while on plants in the field if seed moisture falls below the critical level. Smooth cordgrass breeding efforts also continued. Accessions with superior seed germination rates also showed significant differences for all other vegetative and reproductive traits. Positive correlations were found among all vegetative traits representing plant growth. Conversely, negative correlations between growth traits and rust reaction were observed. Later-flowering accessions were associated with increased spread and tiller density, but not with the other traits. Two field investigations, at Baton Rouge and Grande Terre, Louisiana, showed that seed set varied greatly both within and among accessions. The average seed set at Baton Rouge was 47% and ranged from 0 to 94%. The average seed set across selected genotypes at Grand Terre Island was 51%, ranging from 7 to 83 %. The mean
percent germination was 43 % with a range of 3 to 89%. Compared to the original 126 native accessions, these results demonstrated a significant improvement. Using Random Amplified Fragment DNA Polymorphism (RAPD) and Amplified Fragment Length Polymorphism (AFLP) markers, 40 genotypes from seven accessions were fingerprinted. The similarity coefficient computed from the molecular data ranged from 22% to 89%, indicating a high level of genetic diversity.
Impacts
The LSU AgCenter coastal plants project plays a critical role in identifying and developing superior genotypes of native plants for use in coastal preservation and reclamation. This project also develops seed handling protocols and investigates seed physiology, plant pathogens, and other areas important to development of a coastal reclamation enterprise.
Publications
- Parami, N.P., Amplified Fragment Length Polymorphisms Characterization of Sea Oats. 2003. LSU Electronic Thesis and Dissertations Online: http://etd02.lnx390.lsu.edu/docs/available/etd-1113103-164538/
- Subudhi, P.K., Neil Parami, Alicia Ryan, and S.A. Harrison. 2003. Rescuing the Coast with Biotechnology. Louisiana Agriculture 46(4): 42-44.
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