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Journal American Rhododendron Society

Current Editor:
Dr. Glen Jamieson ars.editor@gmail.com

Volume 38, Number 3
Summer 1984

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Report of the Research Committee 1984 Research Grants
August E. Kehr, Ph.D.

        A total of 26 research proposals from the United States, Canada, and Ireland were received in 1984. These were reviewed and evaluated by the Research Committee at the annual meeting of the Society at Atlanta. In turn, the recommendations of the Research Committee were considered by the Trustees of the American Rhododendron Society's Research Foundation. As a result, the following research grants were funded:
PROJECT LEADER, ADDRESS: Dr. John A. Wott, Center for Urban Horticulture, GF-15, University of Washington, Seattle, WA
OBJECTIVE: To make recent rhododendron and azalea research more accessible and more useful to ARS members and the general gardening public by developing a computerized review of the literature, to be oriented toward practical aspects of growth and culture.
JUSTIFICATION: Much useful information on the growth, culture, and care of rhododendrons and azaleas appears in scientific journals that is not widely available and that is difficult for laymen to understand. Much practical information also appears in growers' journals and other publications with limited circulation and indexing. This project will 1) review this diverse literature, from 1970 to the present, 2) abstract from it the facts and cultural guidelines useful to ARS members and other rhododendron and azalea enthusiasts, and 3) organize this information by categories into a ready reference, keyed to an annotated bibliography. The project will be developed via a data base and data management process in the computer system of the Center for Urban Horticulture. Thus the project will give ARS members easy access to helpful research and experience that are now scattered and little known. Initial access will be by computer printout, but the data could also be the basis for a publication that the ARS could produce for its members.
A.  Select student interested in rhododendrons and azaleas and capable of developing a computer program.
B.  Determine publications to be reviewed and categories for organizing data.
C.  Begin developing data base of facts.
D.  Generate data bank.
ARS LIAISON FOR THIS GRANT: June Sinclair, Seattle Chapter.

PROJECT LEADER, ADDRESS: Dr. Michael A. Dirr, Ms. Mildred Pinnell, Department of Horticulture, University of Georgia, Athens, GA
OBJECTIVE: To assemble into a slide/script or tape presentation the pertinent research being conducted under the auspices of the American Rhododendron Society. To create an awareness that research is beneficial to the Society and explain the nature of short and long term projects.
JUSTIFICATION: At present there is no slide program that can be used by local chapters to explain the nature and scope of rhododendron and azalea research. Presentation would be interesting, enlightening and would hopefully elicit additional research ideas and support from members.
WORK PLAN FOR COMING YEAR: Determine current ARS projects; secure slides and summary of work from researchers; undertake graphics and slide making; present product to ARS research committee for review and possible changes.
ARS LIAISON FOR THIS GRANT: Joseph Coleman, Azalea Chapter.

PROJECT LEADER, ADDRESS: Dr. Robert L. Ticknor, North Willamette Experiment Station, Oregon State University, Aurora, OR
A. To determine tolerance of seedlings of Rhododendron species and crosses to root rot.
B. To select seedlings which have superior growth habit and a wider color range than presently available in cold hardy cultivars.
JUSTIFICATION: Root rot caused by Phytophthora cinnamomi limits growth of rhododendrons in areas with high summer temperatures. Tolerance to this disease could increase the number of "Good Doers." This is an expansion of an agreement with Boyce Thompson Institute, Ithaca, NY, and the cooperation of Cornell Plantations to develop cold hardy rhododendrons in a wider range of color and growth habits.
WORK PLAN FOR COMING YEAR: Crosses based on the results from two years of Phytophthora screening will be done. Inoculate seedlings resulting from crosses done at the Cornell Plantations and at the North Willamette Experiment Station. Select and propagate plants to be sent to Ithaca for cold hardiness testing.
ARS LIAISON FOR THIS GRANT: Dr. Frank Mossman, Portland Chapter

PROJECT LEADER: Dr. Larry Englander, Department of Plant Pathology-Entomology, University of Rhode Island, Kingston, RI
OBJECTIVE(s): Determine: 1) the biology of the pathogen(s) involved: 2) the interacting role of environmental conditions (temperature, moisture) which seem to play a significant part in development of this disease; and 3) the methods by which this problem may be alleviated or avoided, as through changes in cultural practices or the use of pesticides.
JUSTIFICATION: A severe cutting rot problem developed last year, and recurred even more seriously this year for many commercial propagators and rhododendron enthusiasts in the Northeast. This problem shows clear-cut varietal specificity and, if it continues to spread, threatens to limit propagation and dissemination of some of the better cultivars (i.e., Dexters). The pathogen is not one which has been studied on rhododendrons, and conventional control measures, such as fungicide applications, have not worked. It is believed that a complex combination of physical, chemical, and biological conditions may be responsible. These conditions and agents must be studied and control measures determined to avert a widespread epidemic.
WORK PLAN FOR COMING YEAR: Test fungi (already isolated and in culture) on stems of susceptible cultivar ('Scintillation') under various combinations of temperature, moisture and illumination levels, rooting hormone and mix composition, to consistently reproduce disease symptoms. Then, determine disease suppression methods (i.e., selection or prior treatment of cutting stock material, alteration of certain cultural practices during rooting, and/or fungicide selection and application schedule).
ARS LIAISON FOR THIS GRANT: John Alexander, Massachusetts Chapter.

TITLE: Study of the interaction of mycorrhizal fungi with Rhododendron shoots derived from tissue culture and with conventional cuttings under sterile conditions in vitro and under standard conditions in nursery practice.
PROJECT LEADER: Dr. K. Heslin, Dr. G. Douglas, Mr. J. Kelly, The Agricultural Institute, Kinsealy Research Centre, Dublin, Ireland
OBJECTIVES: To establish conditions of substrate and nutrition favouring the association of mycorrhizal soil fungi with shoots derived from tissue culture. To develop procedures to isolate and culture rhododendron - associated mycorrhizal fungi and reassociate fungi with plants under controlled conditions in vitro and under conditions of conventional nursery practice.
JUSTIFICATION: Little is known about the mycorrhizal status of rhododendron grown under standard nursery conditions. There is no information available on the interaction of rhododendrons produced from tissue culture with these beneficial soil fungi. It is important to establish optimal conditions which facilitate the association of mycorrhizal fungi with tissue culture-derived plants since propagation by tissue culture is becoming more commercially popular.
Approach - We can readily produce rhododendrons from tissue culture and achieve rooting in culture tubes and directly in nursery soils. We propose to study the mycorrhizal status of plants derived from tissue culture which are rooted in (a) a sterile substrate (b) conventional peat substrate (c) in substrate supplemented with soil taken from beneath stock plants of rhododendron.
        We shall attempt to isolate and culture mycorrhizal fungi from rhododendron roots and establish reassociation of these indigenous fungal isolates (together with one readily available isolate from UK) with sterile plantlets under controlled conditions in tissue culture.
        Compare rooting frequency of Rhododendron in (a)  substrates containing compatible mycorrhizal fungi, (b)  sterile substrates
        In the longer term we shall compare the growth performance of plants bearing mycorrhizal roots with those that do not and with those that are poorly mycorrhizal.
BENEFITS: This work should identify optimal cultural and soil conditions for facilitating the association of mycorrhizal fungi with plantlets derived from tissue culture. Reassociation of rhododendron roots with mycorrhizal fungi in tissue culture will provide a useful tool for studying interactions under controlled conditions. Successful culture of mycorrhizal fungi should facilitate the isolation of strains which improve growth of rhododendrons, their establishment on impoverished sites and possibly rooting of cuttings.
1.  Obtain shoots from tissue cultures and pre-treat shoots for rooting as previously described. Cultivars include 'Nova Zembla,' 'Pink Pearl,' 'Hugo Koster.' Insert shoots in (a) sterile soil (b) conventional peat substrate (c) sterile substrate supplemented with varying proportions of soil taken from beneath stock plants of Rhododendron. Determine percent roots with mycorrhizal fungi present after 6 weeks, 3 months and one year in each substrate. Grow on plants and assess growth in nursery after two years.
2.  Isolate mycorrhizal fungi from rhododendron roots in Ireland and obtain fungal isolate from UK derived from Calluna roots. Establish conditions favouring reassociation of mycorrhizal fungi with sterile plantlets of rhododendron in vitro. Assess mycorrhizal status of these plants.
3.  Take conventional hardwood cuttings of important cultivars and assess effects of (a) sterile substrate (b) conventional peat substrate (c) sterile substrate supplemented with varying proportions of soil taken from beneath stock plants of rhododendron. Determine % rooting and root quality.
ARS LIAISON FOR THIS GRANT: August E. Kehr, Research Chairman.

The total amount of money granted for these five research projects was $9500, all of which came from the earnings of the endowment fund which the American Rhododendron Society has set up in this Research Foundation. The endowment fund continues to grow each year with gifts of individuals and chapters. The endowment fund remains intact into perpetuity, and only the earnings are expended for funding research. An important source of additions to the endowment fund is from check off money on dues renewal forms. Each year generous members of the Society send in just under $2000 with their annual dues as a part of the check off system.
        In 1984 additional funds came from the sales of plants at the annual meeting at Atlanta as described below:
At the annual meeting of the Society at Atlanta plants of the new evergreen azalea 'Great Expectations' were sold for the benefit of the Society's Research Foundation. A total of 259 plants were sold and a check for $1295 was sent to the Foundation to add to the endowment fund for sponsoring future research. These plants were grown and donated by George and Mary Beasley, and their son Jeff and daughter-in-law, Lisa, Transplant Nursery, Livonia, Georgia, for that purpose. The generosity of the Beasleys is deeply appreciated.
        'Great Expectations' is a very hardy, low growing evergreen azalea with a double flower of mandarin red color. This evergreen azalea was developed by August Kehr from the cross 'Anytime Tetra' x R. nakaharai 'Mariko'. 'Anytime Tetra' is a tetraploid form of 'Anytime' which resulted from colchicine treatment of the diploid form by researchers at the U.S. Department of Agriculture research station at Beltsville, MD. 'Mariko' is an almost prostrate form of R. nakaharai selected by Peter Cox, Perth, Scotland, a member of the new Scottish Chapter.
        CHAPTER RESEARCH CHAIRMEN Every chapter in the Society (with one exception) now has a Chapter Research Chairman. This chairman keeps a file of all the information and materials from the Research Committee, including application forms for research grants. If any member wishes to initiate a research proposal from a university, college, or research station, he may do so by obtaining an application form from the Chapter Research Chairman. In 1983 approval was obtained from the ARS Board of Directors to accept applications for research grants from individual members of the Society, as well as from recognized research institutions. Individuals should send their applications to the Research Committee after it is approved by the Chapter President and Chapter Research Chairman.
        Individual members may wish to obtain grants for such research as local or foreign seed collection for sending seed to the Seed Exchange, developing a slide program for the Slide Library, developing an information booklet for Society members, or perhaps even writing a new book. Such proposals will be evaluated by the Research Committee largely on the basis of the value of the research to the Society membership.

Volume 38, Number 3
Summer 1984

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