Table 3.

The correlation between genetic length of 19 linkage groups on the maternal and paternal P. tremula genetic maps and physical length of P. trichocarpa chromosomes

	P. tremula maternal map	P. tremula paternal map	P. trichocarpa a	P. deltoides b	P. simonii
P. tremula maternal map	1.000000
P. tremula paternal map	0.912140	1.000000
P. trichocarpa	0.911496	0.980897	1.000000
P. deltoides	0.853154	0.926683	0.914898	1.000000
P. simonii	0.899007	0.928977	0.921623	0.939383	1.000000

^aChromosome size refers to the reference genome of P. trichocarpa [6]

^bGenetic length of linkage groups of P. deltoides and P. simonii refers to the corresponding high resolution genetic maps [11]