2008 Annual Report
1a.Objectives (from AD-416)
Development of strategies to control diseases and insect pests of ornamental plants in commercial production systems in the southeastern Gulf Coast states. Development of production practices and plant varieties to improve and standardize vegetable and ornamental plant quality and selection in the southeastern Gulf Coast states.
1b.Approach (from AD-416)
Evaluate use-patterns of disinfectants, model disease progress of Rhizoctonia blight in azalea container production to improve cultural practices and fungicide timing, and monitor infection periods and latency of Camellia twig blight to identify seasonally relevant periods to target control practices. Develop cultural and biological control tactics against insect pests of azaleas and determine phenological traits of arthropod pests in production nurseries to better determine control tactics in the Gulf States region. Identifying host plant resistance of azaleas to the azalea lace bug will be a method of cultural control studied. Biological controls using natural enemies of the azalea lace bug will be analyzed. The biology of the strawberry rootworm, a new pest of azaleas will be determined. Phenological studies will include tree borers, scale insects, and other recurring pests of ornamental production nurseries. Determine factors that regulate growth characteristics and tolerance to environmental stress of vegetable and ornamental crops. Evaluate and screen germplasm for tolerance/resistance to factors affecting plant performance (i.e. heat, cold, and pest), identify/enhance desirable traits, and develop improved varieties for the Gulf States Region. Coordination of pest etiology and control practices and development of new cultivars will serve multiple industry segments by providing multiple management tools that facilitate production practices.
The cause of azalea web blight was shown to have seasonal growth habits including the presence of fungus on healthy stems. Chemicals are being evaluated to obtain pathogen-free cuttings. Based on field data, temperature is a key factor affecting web blight development. For camellia twig blight, a second manuscript was submitted that shows that disease symptoms slow during the growing season. This information will be used when studying infection patterns. A new research entomologist was hired and is continuing the research on an azalea lace bug and strawberry root worm. Lace bug feeding preferences for some cultivars of evergreen azaleas has been submitted for publication. Lace bug resistance is a polygeneic trait according to inheritance and new resistant cultivars are being explored. Progress also includes sampling the developmental stages of the strawberry root worm and continuing work on rearing them on artificial diet to develop laboratory populations for further study. Phylogenetic analysis of the strawberry root worm species complex is also underway. Progress includes data collection from a partial diallel crapemytle study involving 39 families and a total of 3,600 progeny. Inheritance of disease resistance, growth and flowering traits are being analyzed. A second crapemyrtle study is evaluating leaf spot and mildew resistance. Data collection was completed for a five-state crapemyrtle evaluation of 28 commercial cultivars to determine performance across a range of climatic conditions. Crosses were prepared between various dark leaf forms of crapemyrtle to generate families for evaluation. Crosses were also made between leaf spot resistant hibiscus and susceptible cultivars with desirable traits. The first regeneration protocol for ornamental ginger was published. This protocol was later improved and used to establish an micropropagation system for eleven other ornamental ginger species and cultivars. Using the same regeneration system and chemical mutagens, we created artificial tetraploid plants from the dwarf ginger so that they can be hybridized with other tetraploid cutlivars with desired traits. Genetic diversity studies on crapemyrtle are complete and manuscripts are in preparation. The genetic linkage map for hydrangea was expanded with additional molecular markers. DNA-based tools for both crops have been published including examples of plant mislabeling in the industry, plant patent protection, hybrid verification, and DNA fingerprints for unambiguous cultivar identification. Molecular markers were developed for fringe tree, one of the new crops that were added to the research plan. Progress includes studies on alternative substrates produced from pine trees for container nursery and greenhouse production of ornamental plants. Experiments included the effects of nitrogen form on annual crops grown in WholeTree substrates, the effects of irrigation volume on Boston ferns grown in WholeTree substrates and the effects of fertilizer rate on annual crops grown in pine tree residuals. Other studies have been initiated to investigate the suitability of WholeTree substrates for vegetative propagation.
Guidelines for the container production of numerous ornamental crops in WholeTree substrates have been established. As a result, a large greenhouse operation in the southeast has implemented the use of substrates composed of 30% WholeTree for the production of numerous annual and perennial crops. Successful results from continued research on irrigation and nutrient inputs for WholeTree substrates should lead to increased commercial demand for WholeTree substrates. This research contributes to NP 305 (Crop Production), with an emphasis on Component 1 (Integrated Sustainable Crop Production Systems) of the action plan, problem statement 1C.4 (Develop Improved Crop Production Systems for High Quality Greenhouse, High Tunnel, and Nursery Crops).
5.Significant Activities that Support Special Target Populations
|Number of Active CRADAs||1|
|Number of Non-Peer Reviewed Presentations and Proceedings||19|
|Number of Newspaper Articles and Other Presentations for Non-Science Audiences||1|
Rinehart, T.A., Wang, X., Trigiano, R.N. 2008. Plant Pathology Concepts and Laboratory Excercises, Second Edition Chapter 26: Molecular Tools for Studying Plant Pathogens. Book Chapter pg 269-278 CRC Press, Boca Raton, FL 2nd ed.
Rinehart, T.A., Reed, S.M. 2008. Breeding Horticultural Plants. In: Beyl, C.A., Trigiano, R.N. editors. Plant Propagation Concepts and Laboratory Exercises. Boca Raton, LA: CRC Press LLC., Taylor and Francis Group. p. 391-400.
Reed, S.M., Jones, K., Rinehart, T.A. 2008. Production and characterization of intergeneric hybrids between Dichroa febrifuga and Hydrangea macrophylla. Journal of the American Society for Horticultural Science. 133:84-91.
Sakhanokho, H.F. 2008. In Vitro Multiple Shoot Induction and Plant Regeneraton from Shoot Apex of Hibiscus actosella Welw. ex. Hiern. Journal of Crop Improvement. 21:201-208.
Sakhanokho, H.F., Kelley, R., Rajasekaran, K. 2008. First Report of Plant Regeneration via Somatic Embryogenesis from Shoot Apex-derived Callus of Hedychium muluense. Journal of Crop Improvement. 21:191-200.
Pounders Jr, C.T., Rinehart, T.A., Edwards Jr, N.C., Knight, P. 2007. An Analysis of Combining Ability for Height, Leaf Out, Bloom Date and Flower Color for Crapemyrtle. HortScience 42(6):4 pgs.
Fain, G.B., Gilliam, C.H., Sibley, J.L., Boyer, C.R. 2008. Establishment of Greenhouse-Grown Tagetes patula and Petunia xhybrida in 'Whole Tree' Substrates. Acta Horticulturae 782:387-393.
Fain, G.B., Gilliam, C.H., Sibley, J.L., Boyer, C.R. 2008. Production of Annual Vinca (Catharanthus roseus) in WholeTree Substrates. HortTechnology 18:13-17.
Fain, G.B., Gilliam, C.H., Witcher, A.L., Sibley, J.L., Boyer, C.R. 2008. WholeTree Substrate and Fertilizer Rate in Production of Greenhouse Grown Petunia (Petunia*hybrida Vilm) and marigold (Tagetes patula L.). HortScience June1 2008 p. 700-705.
Li, Y.H., Windham, M.T., Trigiano, R.N., Fare, D.C., Spiers, J.M., Copes, W.E. 2007. Evaluation for Resistance to Powdery Mildew in Cornus Species and Hybrids Using a Leafy Disk Assay. Journal of Environmental Horticulture 23:131-133.
Devries, R.E., Trigiano, R.N., Windham, M.T., Windham, A.S., Sorochan, J.C., Rinehart, T.A., Vargas, J.M. 2008. Genetic Analysis of Fungicide Resistant Sclerotinia homoeocarpa Isolates from Tennessee and Northern Mississippi. Plant Disease Vol.92, no.1, pp.83-90.
Wadl, P., Wang, X., Scheffler, B.E., Rinehart, T.A., Trigiano, R. 2007. Microsatellites from Kousa dogwood (Cornus Kousa). Molecular Ecology Notes, online (doi:10.1111/j.1471-8286.2007.02062.x)
Wang, X., Trigiano, R.N., Windham, M.T., Scheffler, B.E., Rinehart, T.A., Spiers, J.M. 2007. Development and Characterization of Simple Sequence Repeats for Flowering Dogwood (Cornus florida L.). Tree Genetics & Genomics Vol 4, no.3 pp.461-468.