Genetic diversity, population structure and phenotypic variation in European Salix viminalis L. (Salicaceae)

S Berlin,J Fogelqvist,M Weih,S J Hanley,N Gyllenstrand,U Lagercrantz,N-E Nordh,A-C Rönnberg-Wästljung,S J Powers,I Åhman,A Karp,H R Hallingbäck,S O Trybush,I Shield

doi:10.1007/s11295-014-0782-5

S Berlin, J Fogelqvist + Show 12 more

Open Access

https://doi.org/10.1007/s11295-014-0782-5

Copy DOI

Abstract

To investigate the potential of association genetics for willow breeding, Salix viminalis germplasm was assembled from UK and Swedish collections (comprising accessions from several European countries) and new samples collected from nature. A subset of the germplasm was planted at two sites (UK and Sweden), genotyped using 38 SSR markers and assessed for phenological and biomass traits. Population structure, genetic differentiation (F ST ) and quantitative trait differentiation (Q ST ) were investigated. The extent and patterns of trait adaptation were assessed by comparing F ST and Q ST parameters. Of the 505 genotyped diploid accessions, 27 % were not unique. Genetic diversity was high: 471 alleles was amplified; the mean number of alleles per locus was 13.46, mean observed heterozygosity was 0.55 and mean expected heterozygosity was 0.62. Bayesian clustering identified four subpopulations which generally corresponded to Western Russia, Western Europe, Eastern Europe and Sweden. All pairwise F ST values were highly significant (p < 0.001) with the greatest genetic differentiation detected between the Western Russian and the Western European subpopulations (F ST = 0.12), and the smallest between the Swedish and Eastern European populations (F ST = 0.04). The Swedish population also had the highest number of identical accessions, supporting the view that S. viminalis was introduced into this country and has been heavily influenced by humans. Q ST values were high for growth cessation and leaf senescence, and to some extent stem diameter, but low for bud burst time and shoot number. Overall negative clines between longitudinal coordinates and leaf senescence, bud burst and stem diameter were also found.

Highlights

Plant breeding still relies, in the main, on the exploitation of existing natural variation
We report on the genetic diversity and population structure of a population of S. viminalis collected from different
This study provides clear evidence of structure in the European S. viminalis accessions from collections in the UK and Sweden and samples from natural populations

Summary

Introduction

In the main, on the exploitation of existing natural variation. Advances in marker technologies and quantitative statistical genetics have led to many powerful approaches for identifying gene-trait associations, even in species with complex genetic systems (Harfouche et al 2012). Amongst these is association mapping, or linkage disequilibrium (LD) mapping, as it is known (Khan and Korban 2012). Association mapping is performed using a genome wide set of markers, with the number required depending on the extent of linkage disequilibrium. Its successful application requires a clear understanding of the genetic structure of natural populations to avoid the downstream detection of spurious associations

Methods

Results

Discussion

Conclusion