Table 1.

Analyses of molecular variance (AMOVA) for three poplar species based on datasets for two markers

Grouping of regions	Source of variation	d.f.	SS	VC	Percent variation	Fixation index
rbcL haplotypes
All samples	Among groups	2	734.907	1.925	83.32	FCT = 0.8332
	Among populations within species	43	65.524	0.101	4.38	FST = 0.877
	Within populations	532	151.200	0.284	12.30	FSC = 0.2327
P. nigra	Among populations	10	20.304	0.137	34	FST = 0.34
	Within populations	135	35.799	0.265	66
P. × jrtyschensis	Among populations	13	40.935	0.183	28.87	FST = 0.289
	Within populations	201	90.535	0.45	71.73
P. laurifolia	Among populations	20	4.285	0.009	6.29	FST = 0.063
	Within populations	196	24.867	0.127	93.71
SSR markers
All samples	Among species (average)	2	1535.34	2.013	28.32	FCT = 0.2832
	Among populations within species	42	678.942	0.470	6.62	FST = 0.3494
	Within populations	1087	5026.09	4.624	65.06	FSC = 0.0923
P. nigra	Among populations	10	130.972	0.376	9.22	FST = 0.0922
	Within populations	271	1003.85	3.704	90.78
P. × jrtyschensis	Among populations	13	215.384	0.369	6.15	FST = 0.0615
	Within populations	418	2349.91	5.622	93.85
P. laurifolia	Among populations	19	332.586	0.639	13.2	FST = 0.132
	Within populations	398	1672.32	4.202	86.8
Nuclear genes
All samples	Among species (average)	2	313.331	1.5804	53.31	FCT = −0.03546
	Among populations within species	29	28.155	−0.04908	−1.66	FST = 0.51659
	Within populations	272	389.783	1.43303	48.34	FSC = 0.53314
P. nigra	Among populations	9	82.674	−0.0513	−0.53	FST = −0.00534
	Within populations	82	791.608	9.6537	100.53
P. × jrtyschensis	Among populations	13	16.811	−0.892	−10.09	FST = −0.1009
	Within populations	120	1167.883	9.732	110.09
P. laurifolia	Among populations	7	28.565	−1.52901	−8.78	FST = −0.08785
	Within populations	70	1325.383	18.934	108.78

d.f. degrees of freedom, SS sum of squares, VC variance components; F_ST, variance among populations; F_SC, variance within populations within groups; F_CT, variance among groups relative to total variance