Announcement of ARS Research Grants
Dr. Harold Sweetman, Chairman ARS Research Committee
Devon, Pennsylvania
Research Grants Awarded in 2007
The Research Committee recommended that the Research Foundation of the American Rhododendron Society provide funding for the following three proposals:
#07-1. Improving Fertilizer and Water Use Efficiency of Container-Grown Rhododendron, Carolyn F. Scagel, USDAARS-Horticulture Crops Laboratory, Corvallis, OR - $5,000.
Summary of Proposal:
The objective of this multi-year study is to characterize the seasonal dynamics of nitrogen uptake and internal cycling in evergreen and deciduous rhododendron cultivars. The effects of liquid and controlled release fertilizer on plant growth and nitrogen uptake will be compared and the influence of nitrogen on water use and photosynthetic performance will be assessed.
It is hypothesized that excess nitrogen during nursery production decreases the efficiency of water use and the quality of container grown rhododendrons. This has important environmental as well as economic implications. Avoiding excess fertilizer run-off and increasing fertilizer efficiency is a hopeful expected outcome this research.
#07-2. Rhododendron Decline of the Southern Appalachian Mountains: Holistic Study of Biotic and Abiotic Factors Compared Between Healthy and Declining Stands, William D. Starrett, Mississippi State University, Mississippi State, MI - $5,000.
Summary of Proposal:
Dieback or decline of
Rhododendron maximum
has been reported in an increasing number of areas in the southern Appalachians and the Great Smokey Mountains National Park. Because of the uncertainty of causal factors, a holistic approach will be taken in an effort to identify abiotic or biotic factors that might cause wild
Rhododendron maximums
to decline at more than 10 sites. Specifically, the holistic approach proposed will compare site factors responsible for increased plant stress, occurrence and importance of fungal pathogens, and changes or loss of mycorrhizal associates compared between healthy and declining stands of rhododendrons. In addition to helping manage rhododendron decline, the data collected may also help aid in the increased understanding of forest decline and the factors involved.
#07-3. Breeding Polyploid Rhododendrons and Azaleas, Thomas Ranney, Department of Horticultural Science, North Carolina State University, Fletcher, NC - $5,000.
Summary of Proposal:
Polyploids are organisms that have more than two complete sets of chromosomes. Polyploidy will be induced chemically in rhododendrons resulting in triploid and tetraploid sets of chromosomes. The objective is to determine ploidy level and genome size of a diverse range of species, hybrids and cultivars of rhododendrons using a combination of flow cytometry and light microscopy.
The goal is to develop improved methods of inducing polyploidy. Pollen germination and viability will be tested in 'Nova Zembla' (2x) vs. 'Super Nova' (4x); 'The Honourable Jean Marie de Montague' (2x) vs. 'Briggs Red Star' (4x); 'Vulcan' (2x) vs. 'Vulcan Tetraploid' (4x) and six other cultivars will also be assessed.
Initial studies revealed that polyploidy has been found to be more prevalent in
Rhododendron
than previously thought. One of the significant expected outcomes of this research is the development of an extensive and informative database on ploidy level and genome size of diverse species, clones and cultivars of
Rhododendron
.