Chloroplast Haplotypes of Northern Red Oak (Quercus rubra L.) Stands in Germany Suggest Their Origin from Northeastern Canada

Jeremias Götz,Konstantin V Krutovsky,Om P Rajora,Ludger Leinemann,Markus Müller,Oliver Gailing

doi:10.3390/f11091025

Abstract

Northern red oak (Quercus rubra L.) is one of the most important foreign tree species in Germany and considered as a major candidate for prospective sustainable forestry in the face of climate change. Therefore, Q. rubra was subject of many previous studies on its growth traits and attempts to infer the origin of various populations of this species using nuclear and chloroplast DNA markers. However, the exact geographic origin of German red oak stands has still not been identified. Its native range widely extends over North America, and the species can tolerate a broad range of environmental conditions. We genotyped individual trees in 85 populations distributed in Germany and North America using five chloroplast microsatellite and three novel chloroplast CAPS markers, resulting in the identification of 29 haplotypes. The new marker set enabled the identification of several new red oak haplotypes with restricted geographic origin. Some very rare haplotypes helped us narrow down the origin of Q. rubra stands in Germany, especially some stands from North Rhine-Westphalia, to the northern part of the species’ natural distribution area including the Peninsula of Nova Scotia, where the most similar haplotype composition was observed, compared to distinct German stands.

Highlights

Northern red oak (Quercus rubra L., section Lobatae) is a forest tree species native to North America, where it occurs from the east coast of Nova Scotia, Canada, and Virginia in the East to Minnesota and Oklahoma in the West
The sample set included 40 German stands and three North American populations studied in Pettenkofer et al [21,23], and 16 natural populations from North America—six studied in Lind & Gailing [24], two studied in Lind-Riehl et al [25], and eight studied in Liesebach & Schneck [3], which all have been genotyped at five chloroplast simple sequence repeat (cpSSR) markers previously [21]
We found evidence for an introduction of the species from various North American populations from the northeastern part of the natural distribution range displayed by the presence of many haplotypes from the northern Great Lakes Region and the northeastern part of the natural range in German stands

Summary

Introduction

Northern red oak (Quercus rubra L., section Lobatae) is a forest tree species native to North America, where it occurs from the east coast of Nova Scotia, Canada, and Virginia in the East to Minnesota and Oklahoma in the West. The species was introduced to Europe in the late 17th century [2] and has become the most important foreign deciduous tree species in Germany considering the large forest area [3,4]. Q. rubra has a short rotation period in forestry compared to the native white oaks Q. robur L. and Q. petraea (Matt.) Liebl. Has a higher productivity than European oak species. Its firewood or fiber properties are similar to that of white oak wood [5]

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