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Department of Horticulture and Crop Science


Masters Exit Seminar

Apr 27, 2015, 10:00am - 11:00am
Andres Bohorquez-Restrepo, Masters Exit Seminar
Joe Scheerens - Co-Advisor
Pablo Jourdan - Co-Advisor
Michelle Jones - SAC committee member
TITLE: Biochemical and Colorimetric Study of Flower Color in Phlox species
Flower color is arguably the most important phenotypic feature of ornamental plants. Variation in flower color can be caused by different factors such as the composition and concentration of pigments, vacuolar pH and the presence of cofactors. Yet quantifying color variation can be challenging. Digital imaging coupled with analytic software is a powerful tool that can transform qualitative measurements of phenotypic characters like color and shape into quantitative data. I have been studying flower color and pigments in Phlox, a genus native to North America that includes an array of colorful flowers often described as purple, lilac, pink, red, orange and blue. The principal pigments of Phlox flowers are anthocyanins, but little is known about pigment variation in this genus. Tomato Analyzer software was used to examine the variation in color from digital images of flowers of 89 Phlox accessions from the Ornamental Plant Germplasm Center. Hierarchical cluster analysis was used to classify the flower color in the sampled population into ten different clusters based on colorimetric data. These clusters provide an objective color category system that can be used to describe the variation in flower colors within Phlox. Anthocyanidins were extracted from the flowers and the relationship between pigments and colorimetric parameters was analyzed. All six main anthocyanidins (delphinidin, cyanidin, petunidin, malvidin, pelargonidin and peonidin) were found in the population. Delphinidin and cyanidin were the major anthocyanidins; petunidin and malvidin often co-appeared; malvidin and petunidin were often found in an inverse relationship with delphinidin. Pelargonidin and peonidin were absent in the majority of samples, but the presence of pelargonidin resulted in color that identified a different cluster. While general trends in anthocyanidin pattern and color were observed, different pigment composition could result in the same color, and nearly identical pigment composition could yield different colors. Thus, flower color in Phlox is only partly influenced by anthocyanidins and other factors must play an important role. This work presents the most extensive color survey in Phlox to date. Biochemical data provides a tool to identify potentially interesting parents in crosses aimed at modifying flower color. The findings provide information relevant for the study of anthocyanin biology in Phlox and for breeding improved cultivars of this important ornamental genus.
Monday April 27 10:00 AM - 11:00 AM 
Kottman 202F (Columbus) video-linked to  Williams 123 (Wooster)