"The region's climate is one
of extremes, and many parts have alkaline soils that developed under
grasslands. So there's less diversity here in commercially available woody
plants adapted to the area than is found in most other parts of our
nation," says Widrlechner. "Because of the broad range of
environments found among the trial sites, it is unusual for any particular
trial plant to perform well at most of them, so system-wide releases are
difficult," he says. "But when plants perform especially well, we
encourage trial-site cooperators to introduce the new plants to the nursery
industry and ultimately to the general public."
Official releases are made through the cooperators' institutions, rather
than through the ARS Plant Introduction Station.
Since many of the cooperating sites have participated in NC-7 since the
1950s, they have developed extensive collections of interesting plants.
"These plants are available for public observation and teaching,"
says Widrlechner. "They're often featured in field days for the benefit of
local nursery and landscape workers."
Where Trial Plants Come From
New plants for the NC-7 trials are acquired in many ways. Three of the most
common are through USDA-supported exploration, seed exchange, and donation.
Germplasm collections are part of the U.S. National Plant Germplasm System and
serve as important sources of genetic diversity for researchers worldwide.
As one of the world's active gene banks, the North Central Regional Plant
Introduction Station provides about 20,000 samples of germplasm free to
researchers around the world each year. As a courtesy, many researchers who
have received seeds reciprocate by sending the Ames station lists of seeds
collected by their personnel.
"Occasionally, direct donations come from institutions with large
numbers of extra plants after exploration. More often, they're propagated by
originators of new selections who are seeking advanced testing in the NC-7
trials. During the last decade, selected plants or cuttings donated for testing
have come from commercial nurseries and university research projects, the
USDA's Natural Resources Conservation Service (NRCS), and Agriculture
Canada," says Widrlechner. "The NC-7 trials also provide
horticulturists and nursery workers throughout the region with an early
examination of new releases from other institutions."
Since 1954, over 550 accessions have been distributed for testing to
participating cooperators at the 36 trial sites. About half were
treesboth evergreen and deciduous; 40 percent were shrubs; and the rest
were vines, groundcovers, and herbaceous perennials.
Each year, Widrlechner and Ovrom assemble a collection of about 8 to 15 new
items for testing. During winter, they send each cooperator a descriptive list
of these plants. The cooperator selects plants to be tested at that site.
"Come spring, we ship or hand deliver the plants to the sites. The
cooperators then plant, observe, and evaluate the selections through the
seasons and prepare performance reports at 1, 5, and 10 years after planting.
These are sent to the Plant Introduction Station for recording," says
Widrlechner has identified some current trends in the landscape and nursery
industries likely to influence introduction of new plants. "Ideally, we
choose trial plants that can meet changing needs," he says.
Guide to the Web Site
According to Ovrom, the NC-7 trials' web site includes information about how
a new plant may be an improvement over currently available ones. This might be
because of aesthetics or adaptation, based on experience with new plants at one
or more sites, or derived from hypothetical performance of wild plants based on
the climate and soil of their native habitats.
"Users can click on a hot link to a summary and find plants suitable to
their location or find trial site locations and cooperators' names and e-mail
addresses. Cooperators are hot-linked to places where they worklike an
arboretum, a botanical garden, a state experiment station, or a plant materials
center operated by NRCS," says Ovrom.
Visit the NC-7 web site at
Hank Becker, Agricultural
Research Service Information Staff.
This research is part of Plant, Microbial, and Insect Genetic Resources,
Genomics, and Genetic Improvement, an ARS National Program (#301) described on
the World Wide Web at http://www.nps.ars.usda.gov/programs/cppvs.htm.
Mark P. Widrlechner and
A. Paul Ovrom are at the USDA-ARS
Regional Plant Introduction Station, Iowa State University, Agronomy Hall,
Room G-212, Ames, IA 50011-1170; phone (515) 294-3511/3454, fax (515) 294-1903.