Road trips for redbuds: An assessment of the genetic diversity and spatial distribution of Cercis canadensis in the US
Ony, Meher, M. Nowicki, W. E. Klingeman, S. Boggess, S. E. Everhart, M. Ginzel, J. Zobel, R. N. Trigiano, and D. Hadziabdic Guerry.  2019.  Phytopathology, 109(10S):S2.172.

Abstract:
Cercis canadensis L. (Eastern Redbud) is a small, understory tree native to 24 states in the eastern United States (US) and Mexico. It is among the earliest deciduous trees that flower in the spring, has lush-green heart-shaped leaves and a wide range of fall foliage colors. Eastern Redbud has become a very popular landscape tree, contributing to more than $27M annually in sales of native trees and cultivars. Because of the wide range of morphological variation, we hypothesized that high genetic diversity among the wild collections of C. canadensis would be evident across its native geographical distribution. We utilized 12 previously developed microsatellite loci in genotyping 691 wild individuals from 74 collection sites across 23 states to determine the population structure and genetic diversity across the Eastern US. Our results indicated a presence of population structure, high genetic diversity (HE=0.67), and high genetic differentiation (FST=0.19) among the collection sites. Two major genetic clusters were inferred by STRUCTURE in our collection. The majority of variation was retained within individuals (70.2%, P < 0.0001) revealed by AMOVA. Only 16.2% (P < 0.0001) of variation was retained among the samples within collection sites, and 13.5% of the variation (P < 0.0001) among the two major population clusters identified. The data suggested that high levels of genetic diversity and spatial structure of our C. canadensis collection could have important implications for habitat management efforts, and future breeding programs to improve desirable horticultural traits.