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

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.

De novo transcriptome assembly, development of EST-SSR markers and population genetic analyses for the desert biomass willow, Salix psammophila

“…The mean number of 10.63 alleles per locus and mean H E 0.689 were determined using 27 developed EST-SSR markers in S. psammophila , which was consistent with SSR-derived genetic diversity in S. viminalis (mean 6.95 alleles per locus and mean H E 0.65 within 84 individuals from seven sampled sites in the Czech Republic; mean 13.46 alleles per locus and mean H E 0.62 within 505 individuals from five populations in Europe)2829 and S. caprea (mean 10 alleles per locus and mean H E 0.58 within 183 individuals from 21 semi-natural woodlands)30. Although the studied genets of S. psammophila were sampled within a 220 kilometres radius, it is a dioecious and cross-pollination species, and its pollen can disperse over long distances due to windy weather in the pollination period and few obstacles to airborne pollen flow in desert regions, which may explain its high levels of genetic diversity.…”

“…The levels of genetic differentiation among naturalised S. purpurea populations are higher than that among native S. eriocephala populations26. High levels of genetic diversity have been revealed in natural populations of S. daphnoides at the westernmost foothills of the Carpathian Mountains27 and S. viminalis in the Czech Republic and Europe2829. Moreover, high levels of gene flow and genetic diversity of S. caprea have been detected in semi-natural woodlands across Ireland30.…”

Genetic structure of dioecious and trioecious Salix myrsinifolia populations at the border of geographic range

“…In contrast, the widespread S. viminalis showed higher genetic variability across Europe (mean He = 0.62), but also significant differentiation between studied regions. Also, populations from Western Russia, which are closer to the centre of the whole Eurasian range, were slightly more variable than those from more westwards parts of Europe (Berlin et al 2014). High genetic variability was also shown in an Irish study of other widespread and common species-Salix caprea (mean He = 0.58), but rarer and spatially restricted subalpine species in Britain, like Salix lanata, Salix lapponum and S. herbacea also possessed high genetic variation (He = 0.706, 0.703 and 0.527, respectively) (Stamati et al 2007).…”

Assessing genetic diversity and population structure of <i>Salix viminalis</i> across Ergun and West Liao basin

“…An average number of 16.45 observed alleles (N a ) and 5.38 effective alleles (N e ) per locus within 330 individuals was higher than studies in Salix like S. caprea (N a = 10.00, N e = 3.90) (Perdereau et al 2014), and S. viminalis in Czech Republic (N a = 13.46, N e = 3.73) (Trybush et al 2012). Relatively high value of observed heterozygosity (H o ) (0.64) and H e (0.74) are comparable to the diversity of Populus nigra (H o = 0.70, H e = 0.73) (Rathmacher et al 2010) and S. viminalis (H o = 0.55, H e = 0.56) (Berlin et al 2014). The high genetic diversity of S. viminalis is probably associated with its biological characters including woody habit, dioecism, wind or insect pollination, and wind seed dispersal (Hamrick et al 1992;Karp et al 2011;Teixeira et al 2014).…”