Genetic diversity and differentiation of pedunculate (Quercus robur) and sessile (Q. petraea) oaks

Girmantė Jurkšienė,Olja A Kovalevič-Razumova,Virgilijus Baliuckas,Oleg Yu Baranov,Dmitry I Kagan

doi:10.1007/s11676-019-01043-3

Abstract

This study was conducted to determine the parent–offspring genetic structure of the pedunculate oak (Quercus robur L.), sessile oak (Q. petraea [Matt.] Liebl.) and their hybrids. Forty half-sib Quercus families and their maternal trees originating from one tree stand in southern Lithuania were analyzed using SSR and RAPD markers. Based on a preliminary study of leaf morphological traits, the individuals separated into six groups. The studied half-sib oak families were also compared for allelic diversity, including group variations; genotypic structure; genetic diversity; and the degree of genetic subdivision and differentiation. The level of genetic variation and subdivision was lower in the hybrid families than in the families of the parental species. Genotypic analysis of the half-sibling offspring showed the asymmetric nature of interspecific hybridization processes of pedunculate and sessile oaks in mixed stands.

Highlights

One approach to solving the considerable challenge of conserving biodiversity, in and the genetic resources of forest tree species in particular is through the study to the genetic structure and polymorphism in oak populations and their peculiarities, which are governed largely by origin.In the current study, we analyzed the progeny of sessile oak [Quercus petraea (Matt) Liebl.], pedunculate oak (Q. robur L.), and their hybrids in the Trakas forest (Lithuania)
We studied the features of the genetic structure of the hybrid offspring of Q. robur × Q. petraea of different origins
These variants reflect local geographic variability and can be used to estimate the gene flow between populations; on the other, they increase the degree of intraspecific subdivision, which reduces the diagnostic value of a marker for interspecific differences between Q. robur and Q. petraea

Summary

Introduction

One approach to solving the considerable challenge of conserving biodiversity, in and the genetic resources of forest tree species in particular is through the study to the genetic structure and polymorphism in oak populations and their peculiarities, which are governed largely by origin. We analyzed the progeny of sessile oak [Quercus petraea (Matt) Liebl.], pedunculate oak (Q. robur L.), and their hybrids in the Trakas forest (Lithuania). Because the two oak species grow under different climatic conditions, the populations formed under these conditions are characterized by high intraspecific genetic variation and differ in terms of phenology, growth rate, shape, and other characteristics (Kleinschmit 1993). The large number of intermediate forms and hybrids makes the differentiation between the two focal oak species more difficult. The authors believe that sessile and pedunculate oaks are ecotypes of the same biological species; Aas (1996) reasoned that, taxonomically and ecologically, they are two distinct species. Muir and Schlötterer (2005) regarded these oaks as distinct species with a

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Conclusion