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Mark P. Widrlechner

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Mark P. Widrlechner

In 1991, the USDA–ARS North Central Regional Plant Introduction Station made available for distribution 129 accessions of germplasm representing 31 genera of herbaceous ornamentals. This number increased to 329 accessions of 42 genera by 1995. During 1991–95, more than 500 seed packets were distributed to fulfill requests for these plants received from a diverse array of public and private researchers. An analysis of this demand together with expert advice from Crop Germplasm Committees and technical considerations, such as ease of culture and seed production, can help set priorities to plan germplasm regeneration to meet future demand. A recent analysis of demand at U.S. National Plant Germplasm System active sites indicated that demand ranging between 0.23 and 0.97 distributions per available accession per year was typical. Of the 42 ornamental genera analyzed in this study, 9 were demanded more frequently than was typical, 10 were demanded less frequently, with the remainder in the typical range. In order of increasing frequency, the nine genera with the highest distribution rates were Verbena, Gypsophila, Echinacea, Lapeirousia, Delphinium, Cerastium, Baptisia, Lilium, and Tanacetum. Six of these genera are represented only by a single available accession. Notably, Echinacea and Tanacetum are of research interest both as ornamentals and as medicinal/industrial crops. This poster gives a brief overview of the economic value of these genera, display the results of the demand analysis, discuss the results relative to recommendations from Crop Germplasm Committees and requestors, and consider how demand can shape management plans for the acquisition and regeneration of ornamental germplasm.

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Mark P. Widrlechner

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Luping Qu and Mark P. Widrlechner

Prunella vulgaris (Lamiaceae), commonly known as selfheal, is a perennial herb with a long history of use in traditional medicine. Recent studies have found that P. vulgaris possesses anti-inflammatory, antiviral, and antibacterial properties, and it is likely that this will lead to increased commercial demand for this species. To date, research publications on P. vulgaris cultivation and genetics are scarce. Using accessions originally collected from different geographical regions, we investigated the breeding system of this species by observing variation in floral morphology, time of pollen release, and selfed-seed set in bagged flowers and isolated plants. Two types of floral morphology, one with exerted styles, extending past open corollas when viewed from above, and the other with shorter, inserted styles, were found among 30 accessions. Two accessions originally collected from Asia uniformly displayed exerted styles, and 27 accessions had inserted styles. One accession from Oregon displayed variation in this trait among individual plants. Microscopic observation of seven accessions, including ones with both exerted and inserted styles, revealed that they all release pollen to some degree before the flowers open. Using bagged flowers, we found that selfed-seed set varied widely among eight accessions, ranging from 6% to 94%. However, bagging may underestimate seed set for some accessions. The two accessions with the lowest rates when using bagged flowers increased in seed set by 350% and 158%, respectively, when we evaluated single, unbagged plants in isolation cages. The accession with 6% selfed-seed set when bagged also had exerted styles. These findings suggest that mating systems in P. vulgaris may be in the process of evolutionary change and that understanding breeding-system variation should be useful in developing efficient seed-regeneration protocols and breeding and selection strategies for this species.

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Roger G. Fuentes-Granados and Mark P. Widrlechner

This study was conducted to determine the inheritance of anthocyanin production and of malate dehydrogenase banding patterns in Agastache rugosa. Results of the study support the hypothesis that anthocyanin production is controlled by a single dominant gene, designated as A, for anthocyanin production. The Mdh-3 banding patterns are controlled by two alleles, each of which associated with a two-banded phenotype. A monomeric quaternary structure of MDH, which is rather atypical among plant species, can be inferred from the results. No linkage was found between the loci governing anthocyanin production and Mdh-3 banding patterns. This is the first report of heritable variability in A. rugosa.

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Mark P. Widrlechner and Sharon K. Dragula

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Mark P. Widrlechner and Sharon K. Dragula

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Michael S. Dosmann, Jeffery K. Iles and Mark P. Widrlechner

Germinability of two, half-sib seed sources of Cercidiphyllum japonicum Sieb. & Zucc. and one seed source of Cercidiphyllum magnificum (Nakai) Nakai was determined after not stratifying or stratifying seeds at 3.5 ± 0.5 °C (38.3 ± 0.9 °F) for 8 days followed by germination for 21 days at 25 °C (77 °F) in darkness or under a 15-hour photoperiod. Stratification was not required for germination, but increased germination percentage, peak value, and germination value for both species. Stratification increased germination of C. japonicum from 42% to 75%, and germination of C. magnificum from 12% to 24%. Light enhanced germination of nonstratified seeds of one source of C. japonicum and of C. magnificum from 34% to 52% and from 8% to 15%, respectively. Stratification improved germinability of both species and obviated any preexisting light requirements the seeds may have had.

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Mark P. Widrlechner, Christopher Daly, Markus Keller and Kim Kaplan

The accurate prediction of winter injury caused by low-temperature events is a key component of the effective cultivation of woody and herbaceous perennial plants. A common method employed to visualize geographic patterns in the severity of low-temperature events is to map a climatological variable that closely correlates with plant survival. The U.S. Department of Agriculture Plant Hardiness Zone Map (PHZM) is constructed for that purpose. We present a short history of PHZM development, culminating in the recent production of a new, high-resolution version of the PHZM, and discuss how such maps relate to winterhardiness per se and to other climatic factors that affect hardiness. The new PHZM is based on extreme minimum-temperature data logged annually from 1976 to 2005 at 7983 weather stations in the United States, Puerto Rico, and adjacent regions in Canada and Mexico. The PHZM is accessible via an interactive website, which facilitates a wide range of horticultural applications. For example, we highlight how the PHZM can be used as a tool for site evaluation for vineyards in the Pacific northwestern United States and as a data layer in conjunction with moisture-balance data to predict the survival of Yugoslavian woody plants in South Dakota. In addition, the new map includes a zip code finder, and we describe how it may be used by governmental agencies for risk management and development of recommended plant lists, by horticultural firms to schedule plant shipments, and by other commercial interests that market products seasonally.

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Roger G. Fuentes-Granados, Mark P. Widrlechner and Lester A. Wilson

The inheritance of five allozymes was studied in anise hyssop (Agastache foeniculum) by analyzing the progeny of controlled crosses. The loci studied [Cat-1, Got-2, Pgm-2, Tpi-1, and Tpi-2] were scored by using starch gel electrophoresis. Segregation analyses of families polymorphic at each of these loci support the following hypotheses: Cat-1 is controlled by a single gene with codominant alleles; Got-2 is controlled by a single gene with codominant alleles coding for dimeric protein products; Pgm-2 is controlled by a single gene with codominant alleles coding for monomeric proteins; and Tpi-1 and Tpi-2 are each controlled by a single gene with codominant alleles coding dimeric protein products. Distorted segregation ratios were observed in some families segregating for Got-2 and Pgm-2. No linkages were detected among any of the cosegregating loci.