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Investigations of morphological and molecular variation in wild and cultivated violets (Viola; Violaceae)

Robarts, Daniel William Howard
http://rave.ohiolink.edu/etdc/view?acc_num=osu1385555287

Abstract Details

2013, Doctor of Philosophy, Ohio State University, Evolution, Ecology and Organismal Biology.
The genus Viola is a large and diverse group of flowering plants. The objectives of this study were to develop and explore new morphological and molecular tools with horticultural and systematic applications. Chapter 1 employed digital image analysis software, Tomato Analyzer, for flower morphology analysis of a 127 accession collection of sect. Melanium violets ("pansy group"). Seventy-seven traits associated with shape, size, and color were scored separately as categorical or continuous variables. The qualitative analysis was favored, capturing more of the variation and receiving higher bootstrap support in cluster analysis dendrograms. Cluster and ordination analyses indicated that the presence of blotch was the primary grouping factor, and secondarily, measures of color and shape (e.g., petal width). Uniformity across accessions of some hybrid morphotypes (e.g., "white with blotch") led to tight clustering across analyses. There were no significant correlations between clustering patterns and accessions' originating country or parent company, as had been previously reported. Chapter 2 builds on the morphological analysis described in Chapter 1 by utilizing sequence-related amplified polymorphism (SRAP) markers to further characterize the collection of Melanium violets. Here, SRAP fragments indicated no significant differences between the horticultural classes of violets, though more were generated from species types than hybrid types of the same ploidy. Bayesian analysis suggested distinctive structure clusters within the collection, but was obscured by high levels of admixture. Some color forms (white, white with blotch, yellow with blotch, and orange) tended to cluster strongly together. Correlation analysis of morphological and molecular datasets, as well as analysis of a combined dataset, underscored the conclusion that some genetic lines could be generalized by blotch presence and flower color. The relationship between these data may help in optimizing germplasm collection management and development of SRAPs by breeders for marker-assisted selection. Chapter 3 describes the genetic diversity within Viola pedata, a North American perennial violet with a bicolorous floral syndrome similar to that seen in taxa of the pansy group. Four hundred fifty-eight individuals collected from 42 unique populations and one cultivar were sampled in eastern North America, and compared using microsatellite markers. Results confirm that this species is a high order polyploid (>4x), and underlying structure indicates previous refugial populations in the Driftless Area of the upper Midwest during previous glacial maxima. A genetic discontinuity east and west of the Appalachian Mountain range was depicted by neighbor-joining, principal coordinates, and Bayesian approaches, a pattern seen in many other plant taxa. Chapter 4 reviews the uses of SRAP markers in the current literature. Since their inception in 2001, over 300 published articles have described the use of markers, with incidence of use increasing every year. Analysis of comparative studies shows SRAP markers generating similar levels of amplicons and polymorphism as AFLP, but with drastically fewer, more simple steps. In presenting relevant case studies, SRAP markers are shown as valuable, but underexplored tools to address hypotheses in topics beyond those in the applied sciences for which they were developed. These research areas include systematics, biogeography, ecology, and conservation.
Andrea Wolfe (Advisor)
Pablo Jourdan (Committee Member)
Laura Kubatko (Committee Member)
Harvey Ballard (Committee Member)
284 p.
Conservation; Horticulture; Plant Sciences
Viola; pansy; pedata; morphometrics; SRAP; microsatellite; phylogeography

Recommended Citations

Citations

  • Robarts, D. W. H. (2013). Investigations of morphological and molecular variation in wild and cultivated violets (Viola; Violaceae) [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1385555287

    APA Style (7th edition)

  • Robarts, Daniel. Investigations of morphological and molecular variation in wild and cultivated violets (Viola; Violaceae). 2013. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1385555287.

    MLA Style (8th edition)

  • Robarts, Daniel. "Investigations of morphological and molecular variation in wild and cultivated violets (Viola; Violaceae)." Doctoral dissertation, Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1385555287

    Chicago Manual of Style (17th edition)

osu1385555287
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This open access ETD is published by The Ohio State University and OhioLINK.