Previous Projects

Here at the OPGC our research projects span a wide array of topics.

  • Genome size and ploidy in the germplasm collection

    An extensive survey was done of the genome size in the germplasm available for CoreopsisPhlox and Rudbeckia, to examine the pattern of cytotype variation within each species and determine the natural occurrence of polyploids in these plants.

  • Evaluation of powdery mildew disease in Phlox

One of the major challenges to Phlox performance in the landscape is the common occurrence of the cosmetic disease of powdery mildew. Very little is known about this disease, so a collaborative project with the Department of Plant Pathology was conducted to examine various aspects of the disease such as analysis of the pathogen, development of an in vitro screening protocol. The ultimate goal of the project was to understand the disease sufficiently to develop effective screening protocols that may permit identification of resistance in the germplasm collection.  

  • Flower color and pigment composition in Phlox

An analysis of the color and anthocyanidin composition of Phlox flowers was undertaken to understand the relationship between the color perceived and the underlying pigment composition. This project was part of Andres Bhorques Restrepo thesis. Flowers were scanned and the color pattern analyzed with Tomato Analyzer software. Anthocyanidin pigments were then extracted and correlated with particular colors.

  • Lepidopteran pollinators for Phlox

Phlox species are not pollinated by bees. Seed production in our accessions of Phlox require the availability of butterflies to achieve pollination under controlled conditions. Since butterflies cannot be readily purchase for use, we investigated protocols to rear and deploy cabbage white butterflies and American painted ladies to achieve pollination. We were successful in rearing the butterflies, although it was a challenging activity, but we encountered difficulties in the production and harvesting of Phlox seed. Until such seed-production details can be optimized, we are holding off further butterfly rearing. At present, seed production in Phlox is done by open pollination.

  • In vitro protocols for germplasm preservation

The OPGC attempted to back-up in vitro the entire clonal collection (primarily of Pelargonium and Begonia). Various approaches were explored to introduce the accessions in culture and then establish methods for slow growth to reduce the frequency of subculture needed to keep the material alive. Additionally, the Phlox collection was also introduced in vitro while various issues associated with seed production and seed quality were examined. The research involved alterations of nutrient media, addition of osmoticum, modification of light quality, and reduction in temperature.

  • Seed quality analysis in Phlox

An important goal of our germplasm development in Phlox was to conserve the germplasm as seed. However, seeds of the perennial species of Phlox have proven much more challenging to produce (pollination requires butterflies and only one or two seeds are produced per fruit), harvest (fruit shattering is a common process through ballistic dispersal of seeds) and germinate (seeds require cold stratification prior to germination). While we produced seed in some accessions, the resulting seed quality was generally low, with extensive growth of fungi and irregular germination.

  • Seed production in Begonia species associated with the development of common cultivated forms

The Begonia collection at the OPGC consists primarily of clonal plants. However, various accessions have produced seed, and a concerted effort has been made to generate seed of as many accessions as possible. To understand more about the seed biology of Begonia, and its potential for long-term storage, a series of studies were undertaken to characterize the seed in terms of germination requirements and accelerated aging. This project was part of Steven Haba's thesis.

  • Field characterization of Rudbeckia and Coreopsis germplasm

The germplasm collection of both Coreopsis and Rudbeckia was grown in the field and observations on its various characteristics were recorded. Additionally, a survey of genome size in the various accessions was undertaken to describe the ploidy characteristic of the different species and cultivars.