Autoradiogram of SSR bands from A (Populus × euramericana (Dode) Guinier), EA4 (Populus × euramericana (Dode) Guinier), and their tetraploid, diploid hybrids, showing that 2n pollen from EA4 was FDR genetic constitution. (a) Primer: 14: GCPM_2453-1, line order from left to right: Marker (from up to down: 400 bp, 300 bp, 200 bp), EA4 (from up to down: A band, B band), A (from up to down: C band, D band, E band), 75# (4×), 421 (2×), 422 (2×), 423 (2×). (b) Primer: 41: GCPM_3345-1, line order from left to right: Marker (from up to down: 300bp, 200bp), EA4 (from up to down: A band, B band), A (from up to down: A band, C band), 75# (4×), 421 (2×), 422 (2×), 423 (2×); (c) Primer: 47: GCPM_3559-1, line order from left to right: Marker (from up to down: 300 bp, 200 bp), EA4 (from up to down: A band, B band), A (from up to down: B band), 75# (4×), 421 (2×), 422 (2×), 423 (2×). (d) Primer: 68: GCPM_432-1, line order from left to right: Marker (from up to down: 300 bp, 200 bp), EA4 (from up to down: A band, B band), A (from up to down: A band), 75# (4×), 421 (2×), 422(2×), 423(2×). (e) Primer: 105: ORPM_29, line order from left to right: EA4 (from up to down: A band, B band), A (from up to down: C band, D band, E band), 75# (4×), 421 (2×), 422 (2×), 423 (2×), Marker (from up to down: 300 bp, 200 bp).