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Title: The Genetic Basis of Upland/Lowland Ecotype Divergence in Switchgrass (Panicum virgatum)

The evolution of locally adapted ecotypes is a common phenomenon that generates diversity within plant species. However, we know surprisingly little about the genetic mechanisms underlying the locally adapted traits involved in ecotype formation. The genetic architecture underlying locally adapted traits dictates how an organism will respond to environmental selection pressures, and has major implications for evolutionary ecology, conservation, and crop breeding. To understand the genetic architecture underlying the divergence of switchgrass (Panicum virgatum) ecotypes, we constructed a genetic mapping population through a four-way outbred cross between two northern upland and two southern lowland accessions. Trait segregation in this mapping population was largely consistent with multiple independent loci controlling the suite of traits that characterizes ecotype divergence. We assembled a joint linkage map using ddRADseq, and mapped quantitative trait loci (QTL) for traits that are divergent between ecotypes, including flowering time, plant size, physiological processes, and disease resistance. Overall, we found that most QTL had small to intermediate effects. While we identified colocalizing QTL for multiple traits, we did not find any large-effect QTL that clearly controlled multiple traits through pleiotropy or tight physical linkage. These results indicate that ecologically important traits in switchgrass have a complex genetic basis, andmore » that similar loci may underlie divergence across the geographic range of the ecotypes.« less
 [1] ;  [2] ;  [1]
  1. Univ. of Texas, Arlington, TX (United States)
  2. Michigan State Univ., East Lansing, MI (United States)
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Grant/Contract Number:
Accepted Manuscript
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Additional Journal Information:
Journal Volume: 6; Journal Issue: 11; Journal ID: ISSN 2160-1836
Genetics Society of America
Research Org:
Univ. of Texas, Arlington, TX (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23). Biological Systems Science Division
Country of Publication:
United States
54 ENVIRONMENTAL SCIENCES; 59 BASIC BIOLOGICAL SCIENCES; Genetic Architecture; Flowering Time; Local Adaptation; QTL; Trait Syndromes
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