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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: Population Structure of Astragalus Filipes Collections from Western North America

Authors
item Bushman, Shaun
item Bhattarai, Kishor -
item Johnson, Douglas

Submitted to: Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 31, 2010
Publication Date: June 1, 2010
Citation: Bushman, B.S., Bhattarai, K., Johnson, D.A. 2010. Population Structure of Astragalus Filipes Collections from Western North America. Botany. 88:565-574.

Interpretive Summary: The vast majority of species used for revegetation in western rangelands are grasses, with few forbs and nearly no legumes currently available. Because of its upright growth habit, potential for agronomic seed production, lack of livestock toxicity, and ability to biologically fix nitrogen in low rainfall regions, Astragalus filipes has promise for use in rangeland revegetation efforts. Genetic diversity and structure assessments for a plant species provide a valuable tool in the decision paradigm concerning which collections should be used to constitute a conservation unit or regional seed souce. In this study, we characterized within-collection genetic diversity, identified cryptic structures or meta-populations, and tested isolation by distance for 67 A. filipes site collections. A large meta-population spanned collections in Oregon, California, northern Nevada, and Idaho, and corresponded to collections with the greatest within-population genetic diversity. Two cryptic structures were detected; one from central Nevada and the other from British Columbia. Although there was significant correlation between genetic and geographic distance matrices and between morphological and geographic distance matrices, there was no correlation between genetic and morphological distance matrices. Genetic diversity followed a general isolation by distance model, while morphological diversity correlated with elevation and precipitation.

Technical Abstract: The vast majority of species used for revegetation in western rangelands are grasses, with few forbs and nearly no legumes currently available. Because of its upright growth habit, potential for agronomic seed production, lack of livestock toxicity, and ability to biologically fix nitrogen in low rainfall regions, Astragalus filipes has promise for use in rangeland revegetation efforts. Genetic diversity and structure assessments for a plant species provide a valuable tool in the decision paradigm concerning which collections should be used to constitute a conservation unit or regional seed source. In this study, we characterized within-collection genetic diversity, identified cryptic structures or meta-populations, and tested isolation by distance for 67 A. filipes site collections. A large meta-population spanned collections in Oregon, California, northern Nevada, and Idaho, and corresponded to collections with the greatest within-population genetic diversity. Two cryptic structures were detected; one from central Nevada and the other from British Columbia. Although there was significant correlation between genetic and geographic distance matrices and between morphological and geographic distance matrices, there was no correlation between genetic and morphological distance matrices. Genetic diversity followed a general isolation by distance model, while morphological diversity correlated with elevation and precipitation.

Last Modified: 12/22/2014
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