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United States Department of Agriculture

Agricultural Research Service

Research Project: ENHANCED MODELS AND CONSERVATION PRACTICES FOR WATERSHED RESOURCE MANAGEMENT AND ASSESSMENT

Location: Grassland, Soil and Water Research Laboratory

Title: Adaptations between ecotypes and along environmental gradients in Panicum virgatum

Authors
item Lowry, David -
item BEHRMAN, KATHRINE
item Grabowski, Paul -
item Morris, Geoffrey -
item KINIRY, JAMES
item Juenger, Thomas -

Submitted to: The American Naturalist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 3, 2014
Publication Date: April 17, 2014
Citation: Lowry, D.B., Behrman, K.D., Grabowski, P., Morris, G.P., Kiniry, J.R., Juenger, T.E. 2014. Adaptations between ecotypes and along environmental gradients in Panicum virgatum. The American Naturalist. 183:682-692.

Interpretive Summary: Patterns and mechanisms of adaptation to different habitats across the natural landscape is important for understanding the differentiation of populations and the evolution of new species. Recent studies of natural selection have focused on ecotype pairs that occur in differing environments. In contrast, field studies of switchgrass, have involved patterns of climatic adaptations across eastern North America and local ecotype adaptations between adjacent habitats. We reviewed field experiments of both levels of variation in switchgrass. We then analyzed several recent field trials to explore the adaptation of several switchgrass cultivars to climate. Finally, we examined the population structure of switchgrass and discussed the emerging view of switchgrass as a species complex containing multiple locally adapted populations and ecotypes. With the recent genome sequencing efforts of switchgrass, it is poised to become a model system for understanding the adaptation of grassland species across eastern North America. The identification of genes involved in climatic adaptations will help to understand the mechanisms of adaptation to the natural landscape and provide useful information for the breeding of high yielding cultivars of switchgrass for different regions.

Technical Abstract: Determining the patterns and mechanisms of adaptation to different habitats across the natural landscape is of fundamental importance to understanding the differentiation of populations and the evolution of new species. Most recent studies of habitat-mediated natural selection in the wild have focused on distinct ecotype pairs that occur in strongly differing environments. In contrast, field studies of switchgrass, Panicum virgatum, have examined both the clinal patterns of climatic adaptations across eastern North America and local ecotype adaptations between adjacent habitats. Here we review the classic field experiments of both levels of variation in P. virgatum. We then conduct a meta-analysis of multiple recent agronomic field trials to explore the adaptation of several switchgrass cultivars to climate. Finally, we examine the population structure of P. virgatum and discuss the emerging view of switchgrass as a species complex containing multiple locally adapted populations and ecotypes. With the recent genome sequencing efforts of switchgrass, it is poised to become a model system for understanding the adaptation of grassland species across eastern North America. The identification of genetic loci involved in climatic adaptations will help to understand the mechanisms of adaptation to the natural landscape and provide useful information for the breeding of high yielding cultivars of switchgrass for different ecoregions.

Last Modified: 9/10/2014
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