Road Trips for Redbuds (Part 1): A Regional Assessment of the Genetic Diversity and Spatial Distribution of Cercis canadensis in the United States
Ony, Meher A., M. Nowicki, W. E. Klingeman, S. Boggess, J. M. Zobel, R. N. Trigiano, and D. Hadziabdic Guerry.  2019.  HortScience, 54(9):S371-S372.

Abstract:
Cercis canadensisL. (Eastern Redbud) is a small, understory tree native to the eastern United States (U.S) and naturallydistributed in 24 states of the eastern U.S. and Mexico. It is one of the earliest flowering trees in the spring, has lush-green heart-shaped leaves throughout the summer, and a wide range of fall foliage colors. Eastern Redbud has become a very popular landscape tree with over $27 million in sales of native trees and cultivars annually. Since this native species shows a wide range of morphological variation, we hypothesized a high genetic diversity among the wild collections of C. canadensis distributed across smaller geographical ranges. To determine the fine-scale population structure and genetic diversity throughout Eastern Tennessee and Northern Georgia, we utilized 15 previously developed microsatellite loci for genotyping 174 individuals from 18 wild collection sites. Our results indicated presence of population structure, high genetic diversity (HE = 0.61), and moderate genetic differentiation (FST = 0.14) among C. canadensis collection sites. The majority of variation was individually based (41.16%, P < 0.001), when compared to variation between the samples within collection sites (33.52%, P < 0.001) as revealed by analysis of molecular variance. Only 20.46% of the variation (P < 0.001) was attributed to the differences among 2 groups. Two major genetic clusters among C. canadensis individuals within the smaller geographical distribution were revealed by Structure. Our data suggests that high levels of genetic diversity and spatial-temporal structure of non-cultivated C. canadensis collections could have important implications for habitat management efforts, and future breeding programs to improve desirable horticultural traits.