Abstract Detail

Classical Genetics

Galliart, Matt [1], Johnson, Loretta C. [1], St. Amand, Paul [2], Poland, Jesse [2], Bello, Nora [2], Knapp, Mary [2], Baer, Sara G. [3], Maricle, Brian R. [4].

ExperImental natural selection of big bluestem grass ecotypes across the Great Plains Climate Gradient.

Andropogon gerardii is the dominant grass of the Great Plains, representing ~70% of biomass. It has wide geographic distribution across the Great Plains precipitation gradient from western Kansas (dry) to Illinois (wet). Ecotypes (xeric, mesic, wet) were reciprocally planted as ecological communities in Colby, Hays, and Manhattan, KS, and Carbondale, IL. It is crucial to understand bluestem responses to climate for conservation, restoration, and agricultural cattle production. We tested for evidence of local adaptation over 5 years using single ecotype plots (community plots seeded with other prairie plants) and plots with all three ecotypes mixed together (community plots containing all three ecotypes and other prairie plants). Planting of ecotypes as a community and over multiple years is rarely done, but offers the most realistic test of local adaptation. We utlized Genotyping-By-Sequencing to identify SNP markers in both plants of known ecotypes and unknown plants from mixed ecotype plots. Principal Component Analyses and population structure show strong genetic differentiation between xeric and wet ecotypes. Outlier analysis in Bayescan identified 64 markers under divergent selection, including GA1 (a gene known to control internode length and height in plants), in which we observe strong ecotype differences between xeric and wet ecotypes. Single ecotype community plots suggest local adaptation to drought with the plants from central KS having higher cover in Hays, KS and plants from Illinois having greater cover in its home site of Carbondale, IL. To analyze the genetic composition of the mixed ecotype community plots, we used the GBS genotype information from plants of known ecotype, then will use this to train a random forest model that allows us to assign unknown individuals from the mixed plots to one of three ecotypes. These multi-year, community plantings show evidence of local adaptation of dry and wet grass ecotypes in reciprocal gardens across the Great Plains. Ultimately these results will provide recommendations to land managers on which climate-adapted source populations of big bluestem is best suited for conservation and restoration planting in future warmer and drier climates.

1 - Kansas State University, Division of Biology, 315 Ackert Hall, Manhattan, KS, 66506, United States
2 - Kansas State University
3 - Southern Illinois University
4 - Fort Hays State University, Department Of Biological Sciences, 600 Park St., Hays, KS, 67601-4099, USA

Keywords:
none specified

Presentation Type: Oral Paper
Session: 4, Classical Genetics & Molecular Ecology
Location: Fort Worth Ballroom 8/Omni Hotel
Date: Monday, June 26th, 2017
Time: 8:15 AM
Number: 4001
Abstract ID:368
Candidate for Awards:None