The ARS Research Committee is interested in the following issues of both
practical and theoretical value to rhododendron growers:
(click to open/close issues list) |
Physiological and genetic factors affecting tolerance of rhododendrons to heat,
cold, drought, insects, and diseases. Why are some rhododendrons more susceptible than others?
How do we use this information to breed more tolerant rhododendrons?
What can be done to counteract the intolerance of current rhododendrons to
various adverse factors, such as powdery mildew and petal blight? Are there chemical or biological
control agents that are effective against these pathogens?
Plant exploration in the U.S., the dissemination of new plant germplasm found,
and the maintenance of such new germplasm.
Polyploidy and aneuploidy in hybrid rhododendrons; chromosome numbers (different
from 2N=26) in Rhododendron species.
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More generally, the Society has identified a broad range of subjects as
appropriate for ARS-funded research. These include: |
► Botanical Research: (click to open/close list) |
Studies on the biosystematics of native
American Rhododendron species, including the collection of superior clones and
populations for distribution to the members through the ARS Seed Exchange.
Support for the introduction of foreign species.
Translation of key botanical research
publications on rhododendrons published in German, Japanese, etc.
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► Breeding Research: (click to open/close list) |
Methods for screening and breeding for cold hardiness.
Breeding for heat tolerance.
Breeding for resistance to root weevils.
Breeding for improved fragrance.
Develop charts for interspecific compatibilities.
Techniques for improving the success of wide crosses and overcoming incompatibility systems.
Improved methods for crossing deciduous with evergreen azaleas.
Computer systems to handle all aspects of record-keeping for breeding programs, with wide
applicability to a large number of amateur breeders.
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► Cultural Research: (click to open/close list) |
Examination of pruning effects across various cultivars.
Develop a schedule and appropriate techniques to establish container-grown plants in soil.
Study the effects of dead heading (removal of spent blossoms and developing seed
pods) on succeeding year's flowering.
Studies on growing rhododendrons and azaleas under competitive trees, such as
pines, maples, dogwoods, tulip poplars, Douglas fir and Madrona.
Pruning and other cultural methods for the rejuvenation of plants that are
too large or rangy.
Low-cost growing media and weed control methods for container plants.
Cultural methods to set flower buds on very young plants.
Methods to protect plants from damage by extreme environmental conditions,
such as hot, dry weather, extreme cold, etc.
Development of a sleeve to enclose stems to avert bark splitting.
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► Cytological & Genetical Research: (click to open/close list) |
Studies on the inheritance of flower color and
relationships between flower color and environmental adaptation.
Determination of chromosome numbers in species
and cultivars, especially for deciduous azalea cultivars.
Studies on the inheritance of fragrance,
indumentum, and truss size.
Production of haploids and/or polyploids.
Tests of tubulin antagonists and antimitotic
chemicals for their ability to induce polyploidization.
Development of methods for in vitro
selection of tissue cultures for resistance to diseases, pests, and extreme
environmental conditions.
Evaluation of species and hybrids for flower
color pigments, especially in sections of the genus not studied to date.
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► Fertilization Practices: (click to open/close list) |
Develop safe, but effective fertilization
schedules for both container-grown and field-grown plants.
Study the role of calcium on plant vigor.
Study the role of phosphorus in bud set and
the effects of high phosphorus on chlorosis, and relationship to the pH of the soil.
Research on the influence of nitrogen on bud set.
Study the effects of fall fertilization.
Study the effects of alfalfa leaf meal and other fertilizer supplements on growth.
Study the role of soluble salts in soil or
artificial media in relation to the predisposition of plants to diseases and pests.
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► Pest Control Research: (click to open/close list) |
Develop reliable tests to screen seedlings for
resistance to diseases such as root rot and to other pests.
Control of Phytophthora dieback.
Biological control of root weevils and borers,
including the use of predaceous nematodes and insects.
Use of terpenes and related compounds to repel root weevils.
Methods for the long-term control of petal blight.
Control of galls on azaleas.
Studies on the cause, nature, and control of slow decline.
Identify cultivars sensitive to Cygon.
Control of Botryosphaeria dieback.
Control of powdery mildew, especially in deciduous azaleas.
Studies on the synergistic effects of anti-transpirants on pesticides.
Research on the effect of red spider mite and
other debilitating pests or conditions on susceptibility to other diseases and pests.
Protection from feeding by rabbits, mice, moles, deer, etc.
Control of Armillaria mellea.
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► Physiological Research: (click to open/close list) |
Chemical induction of hardiness and the
practical applications of hardiness induction.
Cultural manipulations to improve fall hardening.
Prevention of fall flowering.
Physiological factors affecting bud set.
Determination of factors affecting fall
hardening, mid-winter hardiness, and dehardening.
Determination of the physiological differences
between easy-to-root and hard-to-root cultivars.
Correlation of leaf analysis with soil tests.
Interaction of fertility levels and light intensity on plant performance.
Techniques to break dormancy, especially in deciduous azaleas.
Physiological factors controlling root growth
and practical applications in promoting extensive root growth.
Physiological factors affecting disease and
pest resistance and possible application in the area of systemic immunization.
Studies on the effect of chlorinated and/or "hard" water on growth and plant health.
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► Propagation Research: (click to open/close list) |
Research on dwarfing rootstocks.
General development of improved propagation techniques.
Research on seed dormancy in wild species, and techniques to overcome seed dormancy.
Development of optimal methods for seed handling and storage.
Home propagation of hard-to-root cultivars.
Studies on cutting propagation (including the effects of sugars,
willow extract, growth regulators, soaking, and cutting collection date).
Effects of the temperature of the rooting medium on rooting success.
Bulletins, slide presentations, and video tapes demonstrating propagation methods.
Innovative methods for the control of bacterial and fungal contamination in
Rhododendron tissue cultures.
Research on basal callusing and other undesired variants generated by tissue
culture propagation.
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► Review Papers and Popular Publications: (click to open/close list) |
Develop outlines of pest control methods and
fertilizer applications for the average gardener.
Develop small, easy-to-read, "what to do"
booklets on plant problems.
Prepare illustrated manuscripts on all aspects
of the garden culture of rhododendrons and azaleas for particular sets of
environmental conditions.
Develop plans for simple, but effective,
structures for indoor growing of plants and seedlings.
Reprint out-of-print bulletins of interest to
society membership.
Develop slide presentations and/or video tapes
of general interest to society membership.
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► Other Areas of Research: (click to open/close list) |
The Research Committee will consider original
research proposals in areas other than those listed above, provided that the
findings are directly applicable and of value to the membership of the
Society. However, the problems listed are those that were considered
some time ago to be of highest priority and interest to the membership.
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For additional information contact the Chairman of the ARS Research Committee:
E-mail: jmedeiros@holdenfg.org
Phone: 440-602-3819 |