Autoradiogram of SSR bands from A (Populus × euramericana (Dode) Guinier), P (P. × popularis), and their triploid/diploid hybrids, showing that 2n pollen from P was SDR genetic constitution. (a) Primer: 13: GCPM_2434-2, line order from left to right: Marker (from up to down: 300 bp, 200 bp), P (from up to down: A band, B band), A (from up to down: C band, A band, D band), 65# (3×), 73# (3×), 321 (2×), 322 (2×), 323 (2×). (b) Primer: 68: GCPM_432-1, line order from left to right: Marker (from up to down: 300 bp, 200 bp, 100 bp), P (from up to down: A band, B band), A (from up to down: C band), 65# (3×), 73# (3×), 321 (2×), 322 (2×), 323 (2×). (c) Primer: 105: ORPM_29, line order from left to right: Marker (from up to down: 400bp, 300 bp, 200 bp), P (from up to down: A band, B band), A (from up to down: C band, B band, D band), 65# (3×), 73# (3×), 321 (2×), 322 (2×), 323 (2×).