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INVESTIGATOR: Croughan, T. P.; Harrison, S. A.; Subudhi, P. K.; Breitenbeck, G. A.; Cohn, M. A.; Schneider, R. W.; Materne, M. D.

PERFORMING INSTITUTION:
RICE RESEARCH STATION
LOUISIANA STATE UNIVERSITY
BATON ROUGE, LOUISIANA 70893

BIOLOGICAL APPROACHES TO COASTAL WETLANDS RESTORATION

OBJECTIVES: 1) Evaluate Spartina alterniflora somaclones, develop seed encapsulation techniques, and genetically characterize Spartina accessions. 2) Characterize Spartina accessions for seed production, desease resistance, and growth characteristics for use in a recurrent selection program. 3) Identify soil-environmental conditions that limit Spartina growth and identify seed dormancy properties. 4) Implement a large-scale coastal vegetation establishment demonstration project.

APPROACH: This study will concurrently conduct cooperative projects at three locations. Biotechnology research on marsh plants will be conducted at the LAES Rice Research Station in Crowley, LA; marsh plant biology, management, and plant breeding research will be conducted at the LAES Agronomy Department in Baton Rouge, LA; and outfield testing and plant evaluations will be conducted at the USDA-NRCS Plant Materials Center in Golden Meadow, LA and in selected coastal locations in Louisiana.

NON-TECHNICAL SUMMARY: This project will genetically improve plants and develop seed-based propogation technology needed to economically restore extensive areas of eroding or restored coastal wetlands.

PROGRESS: 2002/01 TO 2002/12
Activities included collecting 50 Spartina alterniflora accessions from highly impacted dying marsh sites in Louisiana. Accessions were propagated and expanded to approximately 3,700 containers. Four replicated trials, three in the impacted marsh and one at the USDA/NRCS Golden Meadow Plant Materials Center in Galliano, LA, were established for evaluation. One evaluation was completed at all sites in the fall of 2002. Approximately 800 pounds of clean S. alterniflora seed were harvested in the fall of 2001 and used to aerially seed approximately 30 acres of marsh in the spring of 2002. Data were collected on seed distribution, germination, survival, and stand establishment. For the S. alterniflora breeding program, eight parents were chosen based on superior vegetative growth, plant type, seed yield, and diversity of origin. Harvested seed from crosses were germinated and the 1150 resulting plants will be evaluated in a natural marsh environment. Studies on the seed biology of S. alterniflora indicated that the stratification time at 5C required for 50 percent germination varied among accessions, ranging from 2-3.5 months. The maximal effect of 5C stratification upon germination depended upon the harvest year, ranging from a 4- to 7-month chilling requirement. Stratification at 10C for 2 months prior to 5C chilling did not enhance the subsequent extent of germination and delayed loss of dormancy by 1-2 months compared with seeds continuously stratified at 5C. S. alterniflora cv. Vermilion is cultivated and distributed by licensed plant growers. SCAR (Sequence Characterized Amplified Region) markers provide an inexpensive and rapid method for reliably identifying the Vermilion cultivar. Unique AFLP bands associated with Vermillion have been identified and will be amplified for sequencing on a Li-COR Saga IR2 sequencer. Thirty clones and seedlings of the Vermilion accession of S. alterniflora have been planted in a replicated trial in two locations to determine if Vermilion seedlings are comparable with vegetative clones in performance. The clones are also being DNA fingerprinted to compare the amount of genetic variation between the clones and seedlings. A population of 100 hybrids involving two S. alterniflora lines has been generated for construction of a genetic map and mapping of QTL for seed set and other desirable characteristics. A new disease, named black leaf spot, of S. alterniflora was described. Symptoms consist of dark brown to black oval spots on leaves of all ages. Spots may coalesce and desiccate to give a blighted appearance. Isolations from field material yielded predominantly one fungus that was used to complete Koch's postulates by several inoculation protocols. The causal agent was tentatively identified as Fusarium moniliforme, though the identity has yet to be confirmed. The same pathogen also causes vascular discoloration in stems and a root rot. While this disease appears to be of minor importance in natural stands, susceptibility to this pathogen must be monitored as new varieties of S. alterniflora are developed to guard against inadvertently releasing susceptible varieties.

IMPACT: 2002/01 TO 2002/12
Coastal erosion causes severe environmental damage in numerous coastal wetland areas but is particularly severe in Louisiana where approximately 30 square miles of land are lost to erosion each year.

PUBLICATIONS: 2002/01 TO 2002/12
1. Cohn, M.A. and Gatz, F.D. 2002. A viability test for Spartina alterniflora. Abstracts 7th International Seed Biology Workshop. Salamanca, Spain. p. 152
2. Ryan, A.B., B. Venuto, S. Harrison, P. Subudhi, and M. Materne. 2002. Characterization of Louisiana Native Spartina alterniflora Populations. Proceeding, Southern Branch Amer. Soc. Agron. p:12.
3. Schneider, R. W. and Jones, J. P. 2001. Determining the role of plant pathogens in the coastal marsh dieback: Lessons from agriculture and forestry. Pages 17-18 in: Coastal Marsh Dieback in the Northern Gulf of Mexico: Extent, Causes, Consequences, and Remedies. R. E. Stewart, Jr., C. E. Profftt, and T. M. Charron, eds. USGS Information and Technology Report USGS/BRD/ITR - 2001-0003. 31 pp.
4. Robertson, C. L., Schneider, R. W., and Harrison, S. A. 2002. Black leaf spot caused in Spartina alterniflora by Fusarium moniliforme. Phytopathology 92: S69. (Abstr.).
5. Utomo, H.S., I. Wenefrida, T.P. Croughan, and M. D. Materne. 2001. Louisiana Smooth Cordgrass: Genetic Evaluation Based on DNA Fingerprinting. TurfGrass Trends 10 (11): 8-12.

PROJECT CONTACT:

Name: Croughan, T. P.
Phone: 337-788-7531
Fax: 337-788-7553
Email: tcroughan@agctr.lsu.edu