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United States Department of Agriculture

Agricultural Research Service


Location: Subtropical Horticulture Research

2011 Annual Report

1a. Objectives (from AD-416)
1. Conserving tropical/subtropical ornamental crop genetic resourses and associated information important for the evaluation and utilization of that material. 2. Development and application of new or improved horticultural evaluation procedures and genetic marker-based approaches for genetic diversity assessment of the preceding genetic resourses. 3. Genetic improvement efforts directed to developing new, superior tropical/ subtropical ornamental germplasm. 4. Transfer of technology in the form of tropical/subtropical ormamental crop genetic resourses, associated information, and new, superior tropical/subtropical ornamental germplasm to researchers and breeders worldwide. 5. Evaluate containerized subtropical/tropical ornamental germplasm for its growth responses to different container media components. Where feasible, estimate for this germplasm the heritabilities and other patterns of genetic variation for adaptation/tolerance to the different container media components.

1b. Approach (from AD-416)
Collect new accessions of subtropical/tropical ornamental plants that have commerical potential in the U.S. Evaluate newly collected accessions and existing material, primarily flowering trees and shrubs already on site, using phenotypic characters and molecular makers. Organize the information such that it can be used as descriptors for inclusion in the GRIN system. Utilize the molecular and phenotypical analysis to breed improved germplasm in support of the ornamental industry. Communicate and coordinate subtropical/tropical ornamental horticultural research with local and regional industry, universites, and foreign germplasm effort in Florida, Puerto Rico, and Hawaii.

3. Progress Report
Two dozen additional ornamental germplasm accessions of cycads and palms have been received through germplasm exchange with the Montgomery Botanical Center. Twelve new accessions of Tabebuia species from Cuba were received as seed from a cooperating plant collector. Tabebuia is one of the priority tropical tree genera identified by the Woody Landscape Plant Crop Germplasm Committee for collections development, and the Cuban species are extremely rare and not otherwise represented in American horticulture. The first round of genotyping Zamia populations from the Bahamas with 17 microsatellite loci has been completed. The National Science Foundation funded our Caribbean Zamia project (a collaboration between ARS, Florida International University, Montgomery Botanical Center, and New York Botanical Garden). Zamia sample collections were completed for the Bahamas and Florida. Nine additional microsatellite loci haven been optimized for use in this project, and we have successfully isolated eight single copy nuclear genes that show Single Nucleotide Polymorphism across the populations. WRKY gene sequences have now been obtained for all other genera of palm tribe Cocoseae (tribes Elaeidinae and Bactridinae) and are being analyzed. A new ornamental subshrub germplasm cultivar Turnera diffusa 'Luisa' was released. Five Hippeastrum hybrid clones have been selected for possible patent and release, and will be submitted to the Office of Technology Transfer patent committee for consideration. We are increasing micropropagted stocks of two diploid Hippeastrum clones to increase attempt chromosome doubling with oruzalin early in 2012. We combined our phylogenetic data on Brazilian Alstroemeria species with that of a research group in Munich, Germany.

4. Accomplishments
1. Germplasm release of Turnera diffusa ‘Luisa’. The research area investigated is germplasm enhancement/release of improved genetic resources and varieties of subtropical ornamentals. After five years of evaluation, an accession from a 2005 plant exploration in Puerto Rico was released as a new ornamental. Turnera diffusa ‘Luisa’ is a new, dwarf ornamental subshrub for horticulture that can be produced as an annual bedding plant in temperate regions and as ground cover and edging plant in frost-free areas. Twenty-four requests for material have been fulfilled, including one from the second largest greenhouse producer in the USA. We anticipate that it will be a valuable new crop for the bedding plant and landscape nursery industry which is highly dependent on novel germplasm for economic security.

Review Publications
Namoff, S., Veloz, A., Jimenez, F., Rodriguez-Pena, R.A., Peguero, B., Lewis, C., Moynihan, J., Abdo, M., Maunder, M., Meerow, A.W., Von Wettberg, E., Francisco-Ortega, J. 2010. Sweet drinks are made of this: Conservation genetics of an endemic palm species from the Dominican Republic. Journal of Heredity. 102:1-10.

Meerow, A.W., Ayala Silva, T., Irish, B.M. 2010. Turnera diffusa 'Luisa', a drought tolerant small shrub for warm climates. HortScience. 45(12):1895-1896.

Pathikonda, S., Meerow, A.W., He, J., Mopper, S. 2010. Salinity tolerance and genetic variability in freshwater and brackish Iris hexagona colonies. American Journal of Botany. 97(9):1438-1443.

George, G., Reed, S.T., Tansel, B., Gordon, G.G. 2011. Growth profile of Chamaedorea cataractarum (Cascade Palm)seedlings with different colored plastic mulch. Journal of Agricultural Science. 3(3):39-49.

Bay-Smidt, M.B., Jager, A.K., Krydsfeldt, K., Meerow, A.W., Stafford, G.I., Van Staden, Ronsted, N. 2010. Phylogenetic selection of target species in Amaryllidaceae tribe Haemantheae for acetylcholinesterase inhibition and affinity to the serotonin reuptake transport protein. South African Journal of Botany. DOI: 10.1016/j.sajb.2010.07.016.

Last Modified: 08/22/2017
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