Mark P. Widrlechner
Horticulturist, USDA - Agricultural Research Service
North Central Regional Plant Introduction Station
Iowa State University, Ames, Iowa 50011
Mark P. Widrlechner
Horticulturist, USDA - Agricultural Research Service
North Central Regional Plant Introduction Station
Iowa State University, Ames, Iowa 50011
The following text was originally published in METRIA Proceedings 7:41-47 (1990)
The official title of the NC-7 Project, "New Crops - The Introduction, Multiplication, Evaluation, Preservation, Cataloguing, Enhancement, and Utilization of Plant Germplasm," describes the range of activities conducted at the Plant Introduction Station. Throughout the years, the species of plants maintained by the Station have occasionally changed, but research at the Station has always emphasized the preservation and evaluation of germplasm collections of field and vegetable crops. These germplasm collections form part of the United States National Plant Germplasm System and serve as important sources of genetic diversity for researchers worldwide (White et al., 1989).
There is, however, a unique program at the Station, which addresses some of the regional needs of landscape horticulture. This program, the NC-7 Regional Ornamental Plant Trials, began in 1954 through the efforts of a small group of dedicated horticulturists under the leadership of Professor S.A. McCrory of South Dakota State College (now University) (Dodge, 1962).
The north central United States is a region of climatic extremes and many parts of the region have alkaline soils that developed under grasslands. Because of these conditions, the diversity found in commercially available woody plants adapted to the area is less than that found in most other parts of our nation. The NC-7 Regional Ornamental Plant Trials were started with the ultimate goal of expanding the range of useful plants in the nursery trade. But, rather than serving as a structured introduction program, such as the University of British Columbia Plant Introduction Scheme or Chicagoland Grows, the emphasis in this program has been placed on detailed, long-term evaluations at a broad range of sites rather than on promotion of new plants (Pastore, 1988). Trial site cooperators in the NC-7 Trials cooperate to varying degrees with their local nursery industry to introduce promising materials.
Each year the Horticulturist assembles a collection of about 8 to 15 new items for testing. During the winter, a descriptive list of these plants is sent to each cooperator, and the cooperator selects plants to be tested at that site. During the spring, the plants are shipped or hand-delivered to the sites. The cooperators then establish plantings, observe and evaluate the plants through the seasons, and prepare performance reports one, five, and ten years after planting. These reports are sent to the Plant Introduction Station where they are recorded.
Because of the broad range of environments found among the trial sites, it is unusual for any particular trial plant to perform well at a majority of the sites, making system-wide releases difficult. However, when plants perform especially well at sites, the Horticulturist assists trial site cooperators in introducing the new plants with any official releases initiated through the cooperators' institutions rather than through the Plant Introduction Station.
NC-7 Woody Ornamental Trial Site Cooperators, Site Locations, and e-mail Addresses
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The National Plant Germplasm System funds both domestic and foreign plant exploration to obtain needed germplasm (Perdue and Christenson, 1989). In recent years, only a few of these exploration trips have been specifically for ornamentals, but useful materials may also be collected as an added benefit of explorations for other crops. For example, many plants with potential ornamental value were collected in 1988 by Dr. Maxine Thompson of Oregon State University during her trip to Pakistan to sample its diverse fruit germplasm and an especially attractive white-barked birch was collected in Stavropol, Russia as part of a 1982 forage exploration by Drs. Mel Rumbaugh and Kay Asay. More recently, the USDA and the North American China Plant Exploration Consortium have conducted explorations for ornamentals in China. Some of these collections are now being propagated for testing in our trials.
Trial site cooperators also have been involved in domestic exploration to acquire new plants. Recent collections have emphasized plant populations growing at sites with stresses similar to those encountered in the region. One of the most productive domestic explorations was conducted in 1984 by Drs. James Klett and James Feucht of Colorado State University in the Rocky Mountains.
As one of the world's active gene banks, each year the North Central Regional Plant Introduction Station provides about 20,000 samples of germplasm to researchers around the world (Roath et al., 1990). As a courtesy, many researchers who have received seeds reciprocate by sending the Station lists of seeds collected by personnel at their institutions. Acquiring seeds through seed exchange lists can be problematic. Beyond an occasional problem with quarantine restrictions, the most troublesome problems occur either because of the lack of controlled pollination in cultivated collections (producing unknown hybrids) or because of incorrect identifications (Donnelly, 1989). However, if one is mindful of these potential problems, seed exchange can be a more efficient and inexpensive way to obtain useful material from remote parts of the world than can plant explorations.
Direct donation is another way of obtaining plants for the NC-7 Trials. Occasionally, donations have come from institutions with large numbers of extra plants after exploration. Since 1984, plants from northern Japan and the Soviet Union have been donated by the Chicago Botanic Garden , and plants from South Korea, by the Holden Arboretum and by the National Arboretum .
More deliberate donations result when an originator of a new selection propagates it for advanced testing in the NC-7 Trials. Selected plants or cuttings produced by commercial nurseries and by research projects at many universities, by the USDA Natural Resources Conservation Service , and by Agriculture Canada have been donated for testing during the last decade.
The criteria used to select these plants are subjective and somewhat arbitrary. Factors considered include how a new plant may be an improvement over currently available ones, either because of aesthetics or adaptation, experience with new cultivated plants at a particular site or limited number of sites, and hypothetical performance of new wild plants based on the climate and soil of their native habitats (Ware, 1994).
Other factors that can influence the decision to distribute an accession include ease of propagation and culture, the number and size of the propagules available in a particular year, and the specific interests of trial site cooperators. Many new accessions have unknown propagation requirements, and the Horticulturist is regularly challenged to produce these plants in sufficient number and size. Ideally, trial plants are chosen that can meet future trends in the landscape and nursery industry. Because the plants are evaluated for a ten-year period, it is advantageous to keep up with emerging problems and changing needs.
Some current trends in the landscape and nursery industries influencing the introduction of new plants have been identified in a recent review by Widrlechner (1990). These trends include increased interest in low maintenance and xeriscape plantings, plantings better adapted to urban stresses, more regional diversity through the use of locally adapted plants, edible landscaping, and the use of tissue culture for commercial propagation.
Until 1984, all recordkeeping relied on paper files. The development of the Germplasm Resources Information Network (GRIN) (Perry et al., 1988) led to the development of a new reporting system with data stored in a computerized database. Forms in use before 1984 were modified to allow computer generation and to simplify data entry. These forms are still completed by the cooperators and sent to the Plant Introduction Station, where they are entered onto a computerized database.
Since that time, performance results have been summarized and published in two forms. Popular summaries have been presented to the nursery industry through articles in American Nurseryman. These focus on the best performing plants at a particular trial site. Two have been published, one for the Iowa State University (Iles and Widrlechner, 1992) and the other for Michigan State University (Schutzki and Widrlechner, 1996). A similar paper is being prepared on superior plants at the University of Illinois' site in Urbana. A technical summary examining the performance of landscape plants introduced from the former nation of Yugoslavia, at sites throughout the North Central Region (Widrlechner et al., 1992), analyzed relationships between climatic factors and plant adaptation. This analysis produced a set of criteria for future exploration in Eastern Europe, a topic discussed in greater detail by Widrlechner (1994a, 1994b).
Beyond the valuable data collected by trial site cooperators, good trial results have occasionally led to the naming and introduction of new cultivars. Cultivars introduced as a direct result of the NC-7 Trials include 'Cheyenne' privet (Ligustrum vulgare L.), 'Meadowlark' forsythia (Forsythia europaea Degen & Bald. x ovata Nakai),and 'Smokey' dianthus (Dianthus plumarius L.) (Widrlechner, 1985). Cooperators are now considering the naming and release of populations of Betula nigra and Securinega suffruticosa evaluated in the trials.
Through the NC-7 Trials, extensive performance data on the aesthetic and adaptation characteristics of 541 accessions have been assembled. From 1959 to 1980, factsheets summarizing the performance of many plants were prepared. Specific data from all trial plants are available from the Plant Introduction Station on request.
Although only a few cultivars have been introduced as a direct result of the NC-7 Trials, trial plants can serve as a source of locally adapted propagation material. The NC-7 Trials also provide horticulturists and nursery workers throughout the region with an early examination of new releases from other institutions.
Dodge, A.F. 1962. North Central regional plantings of woody ornamentals and shelter plant introductions. Proc. Intl. Plant Prop. Soc. 12: 179-199.
Donnelly, G.T. 1989. The climate is right. Museum News 68(5): 45-48.
Iles, J.K., and M.P. Widrlechner. 1992. Recommended landscape plants from the heartland. Amer. Nurs. 175(11): 20-27.
Pastore, C.L. 1988. Woody Plant Introduction Programs. M.S. Thesis, University of Delaware.
Perdue, R.E., Jr. and G.M. Christenson. 1989. Plant exploration. Plant Breed. Rev. 7: 67-94.
Perry, M., A.K. Stoner, and J.D. Mowder. 1988. Plant germplasm information management system: Germplasm Resources Information Network. HortScience 23: 57-60.
Roath, W.W., R.L. Clark, M.P. Widrlechner, and R.L. Wilson. 1990. Germplasm resources at the North Central Plant Introduction Station. pp. 84-90. In: Advances in New Crops. J. Janick and J.E. Simon, eds. Timber Press, Portland.
Schutzki, R.E., and M.P. Widrlechner. 1996. New plants on trial. Amer. Nurs. 183(9): 38-46.
Ware, G.H. 1994. Ecological bases for selecting urban trees. J. Arboric. 20(2): 98-103.
White, G.A., H.L. Shands, and G.R. Lovell. 1989. History and operation of the National Plant Germplasm System. Plant Breed. Rev. 7: 1-56.
Widrlechner, M.P. 1985. NC-7 ornamental trials. North Central Nurserymen 7(10): 12-13.
Widrlechner, M.P. 1990. Trends influencing the introduction of new landscape plants. pp. 460-467. In: Advances in New Crops. J. Janick and J.E. Simon, eds. Timber Press, Portland.
Widrlechner, M.P. 1994a. Is Eastern Europe a useful source of new landscape plants for the Midwest? Comb. Proc. Intl. Plant Prop. Soc. 42: 451-455.
Widrlechner, M.P. 1994b. Environmental analogs in the search for stress-tolerant landscape plants. J. Arboric. 20(2): 114-119.
Widrlechner, M.P., E.R. Hasselkus, D.E. Herman, J.K. Iles, J.C. Pair, E.T. Paparozzi, R.E. Schutzki, and D.K. Wildung. 1992. Performance of landscape plants from Yugoslavia in the North Central United States. J. Environ. Hort. 10: 192-198.
Wilson, R.L., R.L. Clark, and M.P. Widrlechner. 1985. A brief history of the North Central Regional Plant Introduction Station and a list of genera maintained. Proc. Iowa Acad. Sci. 92: 63-66.