Mark P. Widrlechner, Horticulturist
US Department of Agriculture - Agricultural Research Service
Email: isumw@iastate.edu
June 2006
Since our last meeting in July 2005, the NCRPIS has acquired 21 new accessions of woody landscape plants and 18 new accessions of herbaceous ornamentals. The two largest groups of new acquisitions resulted from collections made in the Republic of Georgia and an NPGS exchange project with Palestinian Territories. Jeff Carstens and I have also been acquiring wild collections of Cornus alternifolia from throughout its native range.
In 2005, we produced 41 control-pollinated or isolated seed lots of woody-landscape plants, grew out another 56 accessions from seed, and vegetatively re-propagated 63 accessions. The 2005 field season resulted in the successful cage regeneration of 38 accessions of herbaceous ornamentals. In March, we stored the ornamental seeds harvested in 2005 and will soon begin proofing passport data so PI numbers can be assigned to many of the newly available accessions. At the end of 2005, 43% of 1980 ornamental accessions were available for distribution and 32% were backed-up at the National Center for Genetic Resources Preservation (NCGRP) in Fort Collins. Past research with Leigh Towill at NCGRP to develop a cryogenic-storage protocol for dormant vegetative buds of Salix is being tested by Gayle Volk to determine whether it can be adopted as a routine back-up method.
Starting last fall, we attempted to germinate 71 accessions of woody plants, focusing on Aronia, Euonymus, Ligustrum, Physocarpus, and Rhus (most of which can be regenerated in large field cages), with 42 accessions successfully germinated. The 2006 field season has generally been pleasant, but with below-normal precipitation, which may lead to a droughty summer. On the plus side, transplanting and other field work progressed quite quickly this spring.
This spring, we are in the final year of a three-year cage field for about 50 accessions of woody landscape plants (primarily Physocarpus, Spiraea, Diervilla, and Ligustrum), supplemented by accessions of tall, perennial Malvaceae (Alcea, Althaea, and Lavatera) (most of which successfully overwintered from 2005). And we are in the second year of a three-year field for herbaceous perennials, emphasizing Potentilla, Tanacetum, and Lamiaceae. Spaces in field cages were filled this spring through the addition of annuals, primarily Matricaria and Calendula.
Two new nursery fields have been established on our farm during the last year, as we are shifting a significant proportion of the growing-on process from containers to the field. This should help us produce better root systems and reduce our reliance on limited “cave” space for overwintering. Many of the seedlings that were transplanted to the field last fall and this spring will be moved to cages for control-pollinated seed increase, after our existing three-year cage fields are “finished.” We acquired a new mulching wagon similar to the one we saw at Beltsville last year. It’s a great labor-saving device.
Jeff Carstens has completed the process of updating our field books for 2006. Inventories of plants in containers were updated last year, and inventories of field plantings will be updated during the summer, along with the capture of additional images.
Last year, demand for seed samples of woody and herbaceous ornamental germplasm from NCRPIS decreased. In 2005, 14 plants, 123 cuttings, 83 budwood sticks, and 207 seed packets were distributed to meet outside requests for woody and herbaceous ornamental germplasm. This diverse group encompassed 54 genera; those most in demand were Salix (103 cuttings), Fraxinus (80 budwood sticks and 1 seed packet), Cornus (15 packets and 2 plants), Alcea (14 packets), and Malva (14 packets). So far this year, we have filled ornamental germplasm requests for 447 cuttings, 1 root sample, 20 plants, and 102 seed packets.
For 2006, five tree and shrub accessions were chosen for evaluation in the NC-7 Trials, resulting in the distribution of 286 plants for testing (plus 25 replacement plants) at 22 sites and an additional 79 plants to 10 botanic gardens and arboreta. The number of trial sites is the highest since 2002. This year’s shipping process was simplified and less expensive, because four of the five accessions were shipped dormant and bare-root. Typically, about 90% of the trial plants have been grown in containers and shipped shortly after they had begun to leaf out in a cool greenhouse. In addition, last April, Jeff Carstens took a productive trip to deliver these plants and meet with our cooperators and nursery professionals in Missouri, Kansas, Colorado, and Nebraska.
Research on the development of models to predict the likelihood of naturalization of non-native woody plants continues in collaboration with Peter Bristol and Kristen Kordecki at the Chicago Botanic Garden. Data sets are being completed for the Chicago region that are being used to help validate models based on life-history and geographic characteristics that were developed from data collected in Iowa. The ultimate goal of this project is to produce powerful and accurate risk-assessment methods that function on a regional basis. Preliminary results indicate that geographic-risk factors play very similar roles in both Iowa and the Chicago region.
I continue to help oversee the management of the Ornamental Plant Germplasm Center (OPGC), at the Ohio State University (OSU) and work closely with David Tay, Susan Stieve, Jennifer Ehrenberger, and OSU faculty and administrators to facilitate OPGC’s full integration within the NPGS. I helped organize an external planning team last March that has drafted a report with recommendations on future directions for the OPGC. This report is undergoing final review and should be released shortly. The Herbaceous Ornamental CGC, now under Neil Anderson’s leadership, will be holding a two-day session in Illinois in August to assist OPGC staff with implementation and better mobilize professional resources within the research community.
During the past year, we loaded images of many of our ornamental accessions onto the GRIN database, along with summaries of NC7 Trial performance. Pete Cyr, our IT specialist, recently designed easy-to-use software to mass-load image files, and Jeff Carstens is now proficient in using the system. Jeff is also learning about pollination-control techniques for wind-pollinated tree genera, such as Alnus, Betula, and Fraxinus, which hopefully will allow us to increase our throughput for their seed regeneration.
One last project that I’d like to report on is the development of a coordinated plan for the ex situ conservation of North American Fraxinus in the face of Emerald Ash Borer. Earlier this month, Kevin Conrad, Ned Garvey, Candy Gardner, and Dave Ellis from NPGS met with Bob Karrfelt from the US Forest Service and Ken Richards from the Canadian Genetic Resources Program to discuss this topic. Bob is now drafting a collecting strategy that will be distributed to the group for refinement later this summer. In support of these plans, I’ve been assembling a bibliography of published research on the genetic diversity and reproductive biology of North American ash.