Genetic diversity in Astragalus tennesseensis and the federal endangered Dalea foliosa (Fabaceae)1

Abstract

(Ho = 0.103 and HE = 0.121) were more than twice that found in D. foliosa (Ho = 0.037 and HE = 0.043). For both species, levels of heterozygosity were highest in Tennessee and lowest in Illinois, where levels half that found in Tennessee. Differentiation among populations within geographical regions (GSTc = 0.161 and 0.145 for A. tenneseensis and D. foliosa, respectively) was lower than when not clustered by regions (GsT = 0.217 and 0.441). In A. tennesseensis, the majority of species-level genetic diversity was contained within populations (Hs = 0.141 as compared to total diversity HT = 0.179), but in D. foliosa, the opposite was true (Hs = 0.060 as compared to HT =- 0.186). Given the high degree of differentiation among geographical regions, particularly in formerly glaciated Illinois, conservation strategies for these species should include consideration of their geographical affinities.