Population structure within the hard maple complex

Abstract

Sugar maple (Acer saccharum Marsh.) is the most economically important member of the Hard Maple species complex, a group of related species that occupy a range between Canada and Mexico, which are adapted to distinct ecological niches. Sugar maple has been identified as vulnerable to rapid climate change, and sustainable solutions are needed to support its role in the production of maple sugar, as well as timber and nursery production in the northeastern United States. Genetic relationships among sugar maple and its allies are largely unknown. In the current study, genetic relationships of 278 individuals from six hard maple species were assessed using 17 multi-allelic microsatellite (SSR) loci. Genetic variance was partitioned into separate components for variation within and among populations and within and among species. Most of the divergence among populations (FPT = 0.263) reflected interspecific divergence (FST = 0.169), but provenances within species also differed at nontrivial scales (FPS = 0.113). Estimation and testing of paired interprovenance divergence showed that all population pairs were statistically divergent. Principal coordinates analysis indicated that the pattern of radiation observed among these taxa is broadly compatible with geography.