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United States Department of Agriculture

Agricultural Research Service

Research Project: IMPROVED PLANT GENETIC RESOURCES FOR PASTURES AND RANGELANDS IN THE TEMPERATE SEMIARID REGIONS OF THE WESTERN U.S. Title: Morphological and genetic variation among sphaeralcea species

Authors
item Sriladda, Chalita -
item Kratsch, Heidi -
item Larson, Steven
item Kjelgren, Roger -

Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 19, 2012
Publication Date: N/A

Interpretive Summary: Perennial globemallow species in the genus Sphaeralcea have desirable drought tolerance and aesthetics with potential for low-water use landscapes. However, scientific classification of globemallow plants is difficult and ambiguous, which leads to decreased consumer's confidence in the native plant industry. The goal of this study was to test and clarify morphological and genetic differentiation among four putative species. Morphological characteristics of scientific reference specimens were used to generate an independent classification model, and assigned putative species names to herbarium specimens, from Utah State University, and new field specimens collected throughout Utah. Genotic classifications were tested using Bayesian cluster analyses of DNA genotypes. The putative S. grossulariifolia was not significantly different morphologically and genetically from S. coccinea, similar to between S. munroana and S. parvifolia. The composite group of S. coccinea and S. grossulariifolia was distinguished morphologically and genetically from the S. munroana and S. parvifolia composite group, with significant correlation between genotypic and morphological characters overall samples. There was no correlation between geographical and genetic distances when all putative species pooled together. However, the correlation was significant when tested within each composite group, suggesting that these two groups may represent two species. The putative S. munroana appeared to be an ecotype of S. parvifolia.

Technical Abstract: The herbaceous perennial species in the genus Sphaeralcea have desirable drought tolerance and aesthetics with potential for low-water use landscapes. However, taxonomy of these species is ambiguous, which leads to decreased consumer's confidence in the native plant industry. The goal of this study was to test and clarify morphological and genetic differentiation among four putative species. Morphological characteristics of the type specimens were used as species references in Canonical variate analysis to generate a classification model, and assigned putative species names to USU herbarium specimens and field specimens. Genotypic classifications were tested using Bayesian cluster analyses of AFLP genotypes. The putative S. grossularifolia was not significantly different morphologically and genetically from S. coccinea, similar to between S. munroana and S. parvifolia. The composite group of S. coccinea and S. grossularifolia was distinguished morphologically and genetically from the S. munroana and S. parvifolia composite group, with significant correlation between genotypic and morphological characters overall samples. There was no correlation between geographical and genetic distances when all putative species pooled together in the Mantel's correlation tests. However, the correlation was significant when tested within each composite group, suggesting they are con-specific due to isolation-by-distance within each group. Morphological distance exhibited a correlation with geographical distance within the S. parvifolia and S. munroana composite group, suggesting morphological isolation by distance. The putative S. munroana appeared to be an ecotype of S. parvifolia.

Last Modified: 12/18/2014