TABLE 1.

Change in P. nigra N46 DNA methylation levels among regenerated plants of five generations compared with those of donor plants.

MSAP band type	G0	G1	G2	G3	G4	G5
I	442 ± 19	488 ± 11	613 ± 15	616 ± 7	646 ± 6	631 ± 13
II	194 ± 16	151 ± 4	98 ± 8	86 ± 8	66 ± 8	85 ± 7
III	213 ± 3	204 ± 2	153 ± 4	166 ± 10	155 ± 9	167 ± 10
IV	90 ± 3	95 ± 8	76 ± 6	71 ± 7	72 ± 3	56 ± 8
Total	939	938	940	939	939	939
T (%)a	52.96 ± 2.05a	48.03 ± 1.26b	34.75 ± 1.60c	34.43 ± 0.71c	31.20 ± 0.65c	32.84 ± 1.37c
F (%)b	32.27 ± 0.28a	31.91 ± 0.81a	24.35 ± 1.07b	25.24 ± 0.54b	24.14 ± 1.23b	23.75 ± 1.89b
H (%)c	20.70 ± 1.81a	16.12 ± 0.46b	10.40 ± 0.87c	9.19 ± 0.85c	7.06 ± 0.87c	9.09 ± 0.73c

^aTotal methylation level (%) = [(II + III + IV)/(I + II + III + IV)] × 100%. ^bFully methylation level (%) = [(III + IV)/(I + II + III + IV)] × 100%. ^cHemi-methylation level (%) = [(II)/(I + II + III + IV)] × 100%. Type I indicated absence of methylation due to the presence of bands in both EcoRI/HpaII and EcoRI/MspI digest; type II bands appeared only in EcoRI/HpaII digestion but not in the EcoRI/MspI digest; type III generated bands obtained in EcoRI/MspI digest but not in the EcoRI/HpaII digest; and type IV represents the absence of band in both enzyme combinations. The different letters after data means significant deferences at P < 0.05.