Table 1. General information for 12 Salix viminalis populations across two basins in China.
Population River Basin Latitude, Longitude Altitude (m a.s.l.) Samples
MDG1 Mordaga upstream Ergun 51°16´N, 120°44´E 673 30
MDG2 Mordaga downstream Ergun 51°25´N, 120°00´E 572 30
GH Genhe Ergun 50°46´N, 121°30´E 706 30
TL Tuli Ergun 50°29´N, 121°41´E 734 28
KDE Kuduer Ergun 50°02´N, 121°40´E 848 27
ZD1 Zhadun Ergun 49°20´N, 120°40´E 649 30
ZD2 Zhadun Ergun 49°20´N, 120°41´E 650 30
ZD3 Zhadun Ergun 49°19´N, 120°40´E 650 30
YM Yimin tributary Ergun 48°42´N, 119°47´E 662 18
HH Huihe Ergun 48°04´N, 119°38´E 772 17
DHQ Dahaiqing West Liao 44°14´N, 118°20´E 1162 30
HL Heili West Liao 41°21´N, 118°27´E 1049 30
1

Fig. 1. Geographic locations of 12 Salix viminalis populations across two basins in China. [Note: Abbreviations of populations are explained in Table 1].

Table 2. Genetic diversity of 12 populations in Salix viminalis based on 20 SSR markers.
Population Na Ne Ho He FIS Np
MDG1 8.600 4.701 0.671 0.737 0.073 3
MDG2 9.150 4.743 0.637 0.719 0.098 8
GH 9.600 5.176 0.657 0.734 0.083 6
TL 10.50 5.524 0.650 0.754 0.120 14
KDE 9.100 5.549 0.728 0.757 0.020 7
ZD1 9.200 4.275 0.667 0.705 0.037 8
ZD2 8.950 4.596 0.650 0.726 0.079 0
ZD3 9.400 4.709 0.655 0.748 0.104 4
YM 8.200 4.220 0.658 0.712 0.043 2
HH 7.050 4.143 0.653 0.718 0.072 1
DHQ 6.150 2.825 0.542 0.587 0.064 1
HL 3.850 2.187 0.490 0.473 –0.059 2
   Mean 8.313 4.387 0.638 0.698 0.062 4.670
Abbreviations of populations are explained in Table 1. Na = Number of observed alleles; Ne = Number of effective alleles; Ho = Observed heterozygosity; He = Expected heterozygosity; FIS = Inbreeding coefficient among individuals within subpopulation; Np = Number of private alleles.
2

Fig. 2. Estimated population structure of 330 individuals in Salix viminalis with K = 2 and 3. [Note: Abbreviations of populations are explained in Table 1].

Fig. 3. UPGMA tree of 12 populations based on Shriver distance using 10 000 bootstrap replicates. [Note: Abbreviations of populations are explained in Table 1].

Fig. 4. Isolation By Distance (IBD) analysis between FST/(1–FST) and log (geographic distance) among 12 Salix viminalis populations (A) and among 10 populations in Ergun basin (B).

Table 3. Analysis of Molecular Variance (AMOVA) of 12 Salix viminalis populations.
Source of variation Degrees of freedom Sum of
squares 		Mean Squares Estimated variance Explained variance (%)
Total populations
   Between populations 11 382.05 34.73 0.795 6.63
   Within populations 648 4506.32 13.93 6.97 93.37
Two clusters (two basins)
   Between clusters 1 201.40 201.40 0.93 11.49
   Between populations within clusters 10 180.65 18.07 0.19 2.38
   Within populations 648 4506.33 13.93 6.97 86.13
Two subclusters of Ergun basin
   Between subclusters 1 59.07 59.07 0.176 2.33
   Between populations within subclusters 8 92.88 11.61 0.066 0.88
   Within populations 530 3880.71 14.67 7.34 96.80

Fig. 5. Genetic barrier of 12 Salix viminalis populations based on Barrier version 2.2. [Note: Abbreviations of populations are explained in Table 1].